黄土丘陵区不同管理方式下草地优势种群的生态位

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张伟, 何俊皓, 郝文芳. 黄土丘陵区不同管理方式下草地优势种群的生态位. 草业科学, 2016,33(7):1391-1402
Zhang Wei, He Jun-hao, Hao Wen-fang. Niche characteristics of dominant plant populations in grassland of loess hilly region of China with different management styles. Pratacultural Science,2016,33(7): 1391-1402 复制到剪切板

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《草业科学》编辑部

黄土丘陵区不同管理方式下草地优势种群的生态位

张伟, 何俊皓, 郝文芳

西北农林科技大学生命科学学院,陕西杨凌 712100

通讯作者:郝文芳(1968-),女,陕西西乡人,副教授,硕导,博士,主要从事植被生态学与资源植物学研究。E-mail:haowenfang@nwsuaf.edu.cn

第一作者:张伟(1990-),男,重庆巫山人,在读硕士生,主要从事植被生态学研究。E-mail:zwgwyd@163.com

收稿日期: 2016-02-24

基金: 国家林业部公益性行业科研专项——陕北退耕还林区农林景观配置技术研究(201304312)

摘要

以吴起县杨青川流域草地为研究对象,对封育(Enclosure)、放牧(Grazing)、施肥(Fertilization)、刈割(Clipping)、灭鼠(Deratization)5种管理方式的草地群落进行调查,并运用Levins生态位宽度和Pianka生态位重叠指数对5种管理方式下主要植物种群生态位特征进行分析。结果表明,达乌里胡枝子( Lespedeza davurica)、铁杆蒿( Artemisia sacrorum)、赖草( Leymus secalinus)、猪毛蒿( Artemisia scoparia)和硬质早熟禾( Poa sphondylodes)的种群总生态位宽度较大,封育>放牧>施肥>刈割>灭鼠管理模式下,生态位宽度最大的分别是达乌里胡枝子、赖草、紫花地丁( Viola philippica)、达乌里胡枝子和猪毛蒿,生态位宽度值大于4的物种数分别为6、6、3、4和3种。不同管理方式下各种对间的重叠指数平均值由大到小依次封育>放牧>施肥>刈割>灭鼠。施肥管理中,种群间生态位宽度与生态位重叠之间存在线性关系,其它管理方式中种群生态位宽度与生态位重叠之间不存在线性关系。生态位分析表明,封育和放牧管理下种群间对资源的需求趋于相同,彼此间通过竞争共存,有利于群落演替,草地生态系统逐渐得到恢复,施肥、刈割、灭鼠管理使群落物种竞争排序发生变化,破坏了草地生态系统原有的竞争机制,导致群落向简单群落演替。从牧草发展角度出发,封育、施肥和刈割有利于优质牧草生长。

关键词: 草地; 黄土丘陵区; 管理方式; 生态位宽度; 生态位重叠

中图分类号:S812.29 文献标志码:A 文章编号:1001-0629(2016)7-1391-12 doi: 10.11829/j.issn.1001-0629.2015-0647

Niche characteristics of dominant plant populations in grassland of loess hilly region of China with different management styles

Zhang Wei, He Jun-hao, Hao Wen-fang

College of Life Science, Northwest Agriculture and Forest University, Yangling 712100, China

Corresponding author: Hao Wen-fang E-mail:haowenfang@nwsuaf.edu.cn

Abstract

In order to understand the response of niche characteristics of different plant communities to different management methods, five different managed grasslands including enclosure(E), lightly grazing(G), fertilization(F), clipping(C) and deratization(D) were investigated at YangQingChuang valley in Loess Hilly Region, China. Niche breadth and overlap indices were used to measure the niche characteristic of dominant plant populations, based on the field survey data got by “quadrat method”. The results showed that: The niche breadths of Lespedeza davurica, Artemisia sacrorum, Leymus secalinus, Artemisia scoparia and Poa sphondylodes which appeared in five treatments of the grasslands were larger than other species. The rank ordering between niche breadth in every population and total population were different in different management methods. Species which had the biggest niche breadth value in E, G, F, C and D were Lespedeza davurica, Leymus secalinus, Viola philippica, Lespedeza davurica, Artemisia scoparia respectively. And the number of species which had the niche breadth value greater than four in E, G, F, C and D were seven, six, three, three and three respectively. The order of niche overlap was as follows: E>G>F>C>D. In addition, the results demonstrated that there had no linear relationship between the niche overlap and niche breadth of tested species in the grasslands at four management styles except F. Niche analysis indicated that the E and G management styles resulted in the demand for resources tended to be the same between different populations. And different populations can coexist between each other by competition to facilitate the community succession. On the other hand, F, C and D management styles resulted in few individual plant species with strong competitiveness which destroyed the competition mechanism of grassland ecosystem and had negative effects of vegetation restoration. From the perspective of forages development, E, F and C management styles, are advantageous to superior forage grass progress.

Keyword: grassland; loess hilly region; management style; niche breadth; niche overlap

Show Figures

生态位是指种群在时间、空间的位置以及种群在群落中的地位和功能作用^[1]。生态位作为物种的生态学和进化生物学特征的反映, 同时又与种间的相互适应及相互作用密切相关, 已成为评价种间和种内关系及种群在群落中所处地位的重要手段^[2], 在环境保护、资源利用、生物多样性及其形成机制、群落演替等方面有着广泛的应用前景^[3]。

陕北黄土丘陵区是我国水土流失最为严重的地区之一, 生态环境极其脆弱。退耕还林(草)工程实施以来, 该区生态环境得到极大改善, 逐渐形成了一定规模的植被。其中, 草地是受人类活动影响最大的陆地生态系统之一, 在全球碳循环、涵养水源、水土保持和气候调节中起着重要作用^[4]。近些年, 众多学者分别探讨了不同管理方式对退化草地恢复重建的影响。封育可以显著影响草地群落特征, 提高退化草地的生产力^[5]。放牧通过改变植被结构和土壤理化性质增加生境的异质性, 从而造成草地群落植物组分、结构和多样性格局发生变化^{[6, 7]}。施肥使高寒草甸植物群落物种数量减少, 群落结构趋于简单, 物种多样性降低^{[5, 8]}。刈割在抑制和消除草原灌木、提高草地的利用价值等方面作用明显^{[5, 9]}。此外, 部分学者探讨了封育、放牧、施肥等管理方式对草地主要植物物种生态位特征的影响, 表明放牧管理下适口性好的植物优势度降低, 家畜不喜食或不食的和耐牧的植物生态位宽度增加, 生态位宽度较大的物种与其它种群间有较大的生态位重叠^[10]; 施肥使禾草类生长旺盛, 杂草类的优势地位逐渐失去, 生态位宽度和生态位重叠不具备线性关系^[11]; 封育管理下植物群落生态位宽度差异明显, 生态位重叠和种群生态位宽度之间存在一定的线性关系^[12]。可见, 学者普遍认为人为管理可使优势物种的生态位宽度和生态位重叠出现波动, 然而, 在生态位宽度和生态位重叠是否具有线性关系的问题上结论不同。前人对陕北黄土丘陵区草地的研究, 主要集中在群落结构, 土壤理化性质, 封育、火烧管理、播种方式对植被恢复的影响等方面^{[13, 14]}。对草地优势种群生态位特征的研究仅局限于不同封育年限且主要集中在宁夏云雾山自然保护区^{[15, 16]}。本研究通过对吴起县5种管理方式的草地优势种群生态位宽度和生态位重叠的分析, 揭示陕北黄土丘陵区不同管理方式下各种群生态位变化情况, 进一步分析生态位宽度和生态位重叠之间的相互关系, 以期探讨不同管理方式下主要植物种群的分布现状、种间关系和对环境资源的利用状况, 解释不同管理方式下种群的演替机制, 为黄土高原草地生物多样性的保护和草地生态系统的恢复及可持续利用提供科学依据。

1 研究区概况与研究方法

1.1 研究区自然概况

吴起县位于陕西省延安市的西北部(107° 38'37″-108° 32'49″ E, 36° 33'33″-37° 24'27″ N), 属于黄土高原丘陵沟壑区, 土壤以黄绵土为主, 水土流失严重。海拔1 200~1 800 m, 年均气温7.8 ℃, 无霜期96~146 d, 年均降水量478.3 mm, 年均蒸发量400~450 mm, 属典型干旱半干旱地区。植被地带属森林草原带, 现为次生植被, 常见物种有铁杆蒿(Artemisia sacrorum)、茭蒿(A. giraldii)、达乌里胡枝子(Lespedeza davurica)、白羊草(Bothriochloa flaccidum)、长芒草(Stipa bungeana)、阿尔泰狗娃花(Heteropappus altaicus)等。

1.2 样地设置与群落调查

1.2.1 样地设置在延安市吴起县杨青川流域选取封育7年的草地作为研究区(面积约10 hm²), 在研究区内布设5个试验区, 2011年5月起, 分别进行封育(enclosure)、放牧(grazing)、施肥(fertilization)、刈割(clipping)、灭鼠(deratization)管理, 其中封育为对照, 每个处理重复3次。各试验区间隔100 m以上, 样地面积为100 m× 100 m。

样地布设。1)封育:2011-2014年继续围栏封育; 2)放牧:于2011-2014年的5月-9月, 每隔1个月进行1次放牧, 放牧强度为0.5只羊· (hm²· d)^-1, 属轻度放牧^[17]; 3)施肥:自2011-2014年起, 每年5月施复合肥(其中总氮20.6%、有效磷9.8%、钾10.4%), 施肥量为600 kg· (hm²· a)^-1; 4)刈割:2011-2014年每年9月刈割一次; 5)灭鼠:2011-2014年, 每年4月、7月、10月采用见洞投毒的方法投放毒饵进行灭鼠。样地概况见表1, 管理方式改变前, 对各样地进行植被调查, 结果显示, 各样地主要优势物种相同, 物种种类差异不显著(P> 0.05)。

表1 样地概况 Table 1 Survey of the plots

1.2.2 群落调查于2011年和2014年 8月进行群落调查, 每种管理方式的样地随机布设25个1 m× 1 m的草本样方。调查植物种类、高度、盖度、多度及频度。记录地理位置、海拔、坡向以及坡度。

1.3 数据处理

1.3.1 重要值计算物种重要值(IV)^[18]:

IV=(相对盖度+相对多度+相对高度+相对频度)/4。

1.3.2 生态位宽度测定 Levins生态位宽度^[19]:

B_i=- $\begin{matrix} \overset{n}{\sum_{j = 1}} \end{matrix}$ (P_ijlnP_ij).

式中:B_i为i种的Levins生态位宽度指数, P_ij表示种i对第j个资源的利用占它对全部资源利用的频度, P_ij=n_ij/N_ij, N_ij=∑ n_ij, n_ij为物种i在第j资源位上的重要值, 本研究用样方代表资源位, 下同, n为样方数(n=25)。

生态位总宽度B^[19]:

B= $\begin{matrix} \sqrt[]{\overset{r}{\sum_{i = 1}} {B_{i}}^{2}} \end{matrix}$ .

式中:B_i是物种在第i个群落类型(样地)的生态位宽度, r为群落类型的数目。

1.3.3 生态位重叠值测定 Pianka生态位重叠^[20]:

O_ik= $\begin{matrix} \frac{\overset{n}{\sum_{j = 1}} P_{ij} P_{ij}}{\sqrt[]{\overset{n}{\sum_{j = 1}} P_{ij}^{2} \overset{n}{\sum_{j = 1}} P_{kj}^{2}}} \end{matrix}$ .

式中:O_ik为种i和种k生态位重叠指数, P_kj为种k在第j个资源位上的重要值占该物种在整个资源序列的总重要值的比例, n、P_ij同上。

种群间生态位重叠指数的平均值=样地内优势物种间生态位重叠值总数/总种对数^[21]。

1.4 数据分析

运用Excle 2010计算不同管理方式下草地优势物种的重要值、生态位宽度、生态位总宽度和生态位重叠值, 采用SPSS 20.0软件对不同管理方式的草地优势种群间生态位重叠指数的平均值进行单因素方差分析, 并用Duncan法对测定数据进行多重比较。

2 结果与分析

2.1 不同管理模式草地优势种群生态位宽度变化

陕北黄土高原退耕区草地主要优势物种的生态位总宽度从大到小的顺序依次为达乌里胡枝子> 铁杆蒿> 赖草(Leymus secalinus)> 猪毛蒿(Artemisia scoparia)> 硬质早熟禾(Poa sphondylodes)> 大针茅(S. grandis)> 长芒草> 阿尔泰狗娃花, 且其生态位总宽度值均大于6.9(表2)。

表2 不同管理模式的草地优势种群生态位宽度比较 Table 2 Niche breadth comparison of dominant species in different management styles of grassland

编号 Code	植物种名 Plant species	管理方式Management style					总生态位宽度 Total niche breadth
编号 Code	植物种名 Plant species	封育 Enclosure	放牧 Grazing	施肥 Fertilization	刈割 Clipping	灭鼠 Deratization	总生态位宽度 Total niche breadth
1	达乌里胡枝子Lespedeza dahurica	4.59	1.94	4.27	5.17	1.42	8.94
2	铁杆蒿Artemisia sacrorum	2.10	3.28	4.05	3.87	4.23	8.58
3	赖草Leymus secalinus	4.11	5.30	1.02	4.86	1.06	8.41
4	猪毛蒿Artemisia scoparia	2.81	3.20	2.15	1.08	5.16	7.79
5	硬质早熟禾Poa sphondylodes	4.23	1.03	0.00	2.83	3.63	7.76
6	大针茅Stipa grandis	4.59	1.24	2.93	1.08	4.92	7.52
7	长芒草Stipa bungeana	4.24	4.32	3.06	1.08	1.81	7.10
8	阿尔泰狗娃花Heteropappus altaicus	1.99	1.80	4.63	2.55	2.08	6.90
9	紫花地丁Viola philippica	4.31	4.39	1.64	2.06	1.06	6.78
10	紫花苜蓿Medicago sativa	0.00	4.80	0.00	4.16	0.00	6.35
11	蛇莓Duchesnea indica	2.79	4.13	1.07	3.17	0.00	6.01
12	鹅观草Roegneria kamoji	0.00	2.08	0.00	0.00	3.75	5.90
13	茭蒿Artemisia giraldii	0.00	2.78	0.00	2.68	0.00	5.40
14	翻白委陵菜 Potentilla discolor	2.40	4.03	2.08	1.03	1.15	5.36
15	旱芦苇 Phragmites commun	0.00	0.00	0.00	3.12	0.00	5.13
16	白羊草Bothriochloa flaccidum	0.87	0.00	2.88	4.09	0.00	5.12
17	香青兰Dracocephalum moldlavica	3.05	1.17	1.01	0.00	1.05	4.80
18	抱茎苦荬菜Ixeris sonchifolia	2.03	1.44	1.09	2.70	2.59	4.74
19	刺儿菜Cephalanoplos segetum	1.02	3.62	0.00	2.10	1.05	4.56
20	披针叶黄华Thermopsis lanceolata	0.00	1.55	0.00	0.00	0.00	4.18
21	冰草Agropyron cristatum	0.00	0.00	0.00	1.09	0.00	4.15
22	老鹳草Geranium wilfordii	1.06	0.00	0.00	0.00	0.00	4.14
23	角蒿Incarvillea sinensis	1.53	1.03	0.00	0.00	0.00	3.96
24	山野豌豆Vicia amoena	0.00	0.00	0.00	1.18	0.00	3.95
25	二裂苇菱菜Potentilla bifurca	2.89	1.07	0.00	0.00	0.00	3.09
26	小花鬼针草Bidens pilosa	2.78	1.02	0.00	0.00	0.00	2.97
27	米口袋Gueldenstaedtia multiflora	1.40	1.09	1.70	0.00	0.00	2.67
28	狗尾草Setaria virids	0.00	1.00	0.00	1.25	0.00	2.61
29	裂叶堇菜Viola dissecta	1.07	1.89	1.01	0.00	0.00	2.39
30	甘草Glycyrrhiza uralensis	0.00	0.00	1.02	0.00	1.98	2.23
31	草木樨状黄芪 Astragalus melilotoides	0.00	0.00	1.06	1.03	0.00	1.79
32	假苇拂子茅Calamagrostis pseudophragmites	1.06	1.42	0.00	0.00	0.00	1.77
33	棉团铁线莲Clematis hexapetala	0.00	1.60	0.00	0.00	0.00	1.60
34	中华隐子草Cleistogenes chinensis	0.00	1.08	0.00	0.00	0.00	1.55
35	车前草Plantago asiatica	1.06	1.02	0.00	0.00	0.00	1.47
36	糙隐子草Cleistogenes squarrosa	0.00	0.00	0.00	0.00	0.00	1.01

表2 不同管理模式的草地优势种群生态位宽度比较 Table 2 Niche breadth comparison of dominant species in different management styles of grassland

封育的群落中, 大针茅、达乌里胡枝子、紫花地丁(Viola philippica)、长芒草、硬质早熟禾及赖草的生态位宽度值较大, 依次为4.59、4.59、4.31、4.24、4.23和4.11。放牧的草地中生态位宽度值较大的种群为赖草、紫花苜蓿(Medicago sativa)、紫花地丁、长芒草、蛇莓(Duchesnea indica)和翻白委陵菜(Potentilla discolor), 其生态位宽度值分别为5.30、4.80、4.39、4.32、4.13和4.03, 该群落生态位宽度较大的草种较封育群落变化较大, 赖草在封育群落中并不占优势, 排在第6位, 紫花苜蓿在封育群落中未出现, 紫花地丁、长芒草、蛇莓和翻白委陵菜生态宽度拓宽了; 施肥管理的群落中阿尔泰狗娃花、达乌里胡枝子和铁杆蒿的生态位宽度值较大, 依次为4.63、4.27和4.05, 其中达乌里胡枝子的生态位宽度仍然处于优势地位, 而阿尔泰狗娃花、铁杆蒿的生态位宽度值有所上升, 分别从第15、13位上升到第1、3位, 大针茅由封育管理的首位下降到第5位, 紫花地丁、长芒草、硬质早熟禾及赖草的生态位宽度下降。

刈割管理方式的草地中, 生态位宽度较大的依次为达乌里胡枝子、赖草、紫花苜蓿和白羊草, 其值分别为5.17、4.86、4.16和4.09, 与放牧管理相比赖草和紫花苜蓿分别从第1位、第2位下降到第2位、第3位, 而与封育管理相比, 赖草和紫花苜蓿的生态位宽度有所上升。与其它管理方式相比, 达乌里胡枝子生态位宽度出现最大值, 白羊草的生态位宽度有所上升, 成为优势物种。灭鼠管理的草地中生态位宽度较大的为猪毛蒿、大针茅和铁杆蒿, 其生态位宽度值分别为5.16、4.92和4.23, 其它物种生态位宽度较小。与放牧、封育、施肥、刈割4种管理方式的草地相比, 猪毛蒿在灭鼠管理草地中的生态位宽度值上升幅度较大, 分别从第8位、第9位、第7位、第18位上升到首位。

总生态位最大的达乌里胡枝子在刈割管理的草地中生态位宽度最大, 为5.17, 而在封育和施肥的草地中其生态位宽度均大于4, 在放牧、灭鼠管理下其生态位宽度值相对较小。管理方式改变前的生态位宽度最大的长芒草仅在放牧和封育的草地中生态位宽度较大, 而在其它群落中生态位宽度值较小。放牧和封育这两种管理模式下, 生态位宽度值大于4的物种数较多, 分别有6和7种, 而在施肥、刈割、灭鼠管理模式下均有3种。

2.2 不同管理模式草地优势种群各种对的Pianka生态位重叠指数

不同管理方式下各种对间的重叠指数平均值由大到小依次为封育> 放牧> 施肥> 刈割> 灭鼠, 即各种对利用资源种类与利用资源方式的相似程度分别为0.73、0.71、0.69、0.63和0.59(图1)。

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图1 不同管理模式下群落优势物种间生态位重叠指数的平均值
注:不同小写表示不同管理模式的草地优势种群间生态位重叠指数平均值间差异显著(P< 0.05)。Fig.1 Average value of niche overlap index of dominant species in communities at different management styles
Note:Different lower case letters show significant difference among different average value of niche overlap index of dominant species in communities at different management styles at 0.05 level.

封育管理的草地10种优势物种间生态位重叠值大于0.9的有7对, 小于0.50的有4对, 介于0.50~0.59、0.60~0.69、0.70~0.79和0.80~0.89的种对数分别有8、5、11和10对(表3)。重叠值较大的物种对为铁杆蒿和长芒草、紫花地丁和二裂委陵菜(Potentilla bifurca)、猪毛蒿和紫花地丁, 其重叠值依次为0.96、0.95和0.95, 最小的为猪毛蒿和大针茅, 其重叠值为0.40。封育管理的群落中, 各物种与其它9个物种重叠值的平均值最大的为赖草(0.82)。

表3 封育管理的草地优势种生态位重叠指数 Table 3 Niche overlap index of dominant species in the enclosured grassland

放牧管理的草地中各种对生态位重叠值≥ 0.90的有7对, 介于0.50~0.59、0.60~0.69、0.70~0.79和0.80~0.89的种对数分别有5、6、14和7对, 小于0.50的有6对(表4)。重叠值较大的种对依次为翻白委陵菜和刺儿菜(Cephalanoplos segetum)、赖草和紫花地丁、赖草和长芒草以及紫花地丁和紫花苜蓿, 其值依次为0.94、0.94、0.92和0.92。该群落中10个优势物种中各物种与其它9个物种重叠值的平均值最大的为赖草(0.83), 最小的为鹅观草(0.57)。

表4 放牧管理下草地优势种生态位重叠指数 Table 4 Niche overlap index of dominant species in the lightly grazed grassland

施肥管理的草地中优势种对生态位重叠值小于0.50的有8对, 介于0.50~0.59、0.60~0.69、0.70~0.79和0.80~0.89的种对数分别有4、9、11和8对, 大于0.9的有5对(表5)。重叠值较大的种对从大到小依次为达乌里胡枝子和阿尔泰狗娃花、大针茅和米口袋、达乌里胡枝子和铁杆蒿以及铁杆蒿和长芒草, 其值分别为0.93、0.92、0.91和0.91, 重叠值最小的为猪毛蒿和米口袋, 其值为0.30, 各物种与其它9个物种重叠值的平均值最大的为达乌里胡枝子(0.79), 最小的为米口袋(0.58)。

表5 施肥管理下草地优势种生态位重叠指数 Table 5 Niche overlap index of dominant species in the fertilized grassland

刈割管理的草地中优势种对生态位重叠值大于0.90的有3对, 从大到小依次为赖草和旱芦苇、铁杆蒿和旱芦苇以及阿尔泰狗娃花和蛇莓, 其值分别为0.93、0.93和0.91(表6)。重叠值介于0.50~0.59、0.60~0.69、0.70~0.79和0.80~0.89的种对数分别有5、5、9和11对, 小于0.50的有12对, 重叠值最小的为硬质早熟禾和阿尔泰狗娃花, 其值为0.18。各物种与其它9个物种重叠值的平均值最大的为旱芦苇(0.78), 最小的为白羊草(0.38)。

表6 刈割管理下草地优势种生态位重叠指数 Table 6 Niche overlap index of dominant species in the grassland of clipping

灭鼠管理的群落中各种对重叠值大于0.90的只有铁杆蒿和大针茅, 其值为0.91, 重叠值小于0.5有16对, 其中最小的为长芒草和阿尔泰狗娃花, 其值为0.16, 重叠值介于0.50~0.59、0.60~0.69、0.70~0.79和0.80~0.89的种对数分别为7、5、8和8对(表7)。各物种与其它9个物种重叠值的平均值最大的为铁杆蒿(0.71), 最小的为阿尔泰狗娃花(0.42)。

表7 灭鼠管理下草地优势种生态位重叠指数 Table 7 Niche overlap index of dominant species in the grassland of deratization

结合表2可以看出, 不同管理方式的草地中, 生态位宽度最大的种群未必与其它物种有最大的生态位重叠, 如封育的草地, 生态位宽度最大的为大针茅, 而生态位重叠指数最大的种对为铁杆蒿和长芒草间的0.96, 各物种与其它9个物种重叠值的平均值最大的为赖草; 放牧的群落中生态位宽度最大的为赖草, 各物种与其它9个物种重叠值的平均值最大的为赖草, 而生态位重叠值最大的为翻白委陵菜和刺儿菜间的0.94, 其次为赖草和紫花地丁间的0.94; 刈割管理方式下生态位宽度值最大的为达乌里胡枝子, 而生态位重叠值最大的为赖草和旱芦苇间的0.93, 各物种与其它9个物种重叠值的平均值最大的为旱芦苇; 灭鼠管理的草地中, 生态位宽度值最大的为猪毛蒿, 生态位重叠值最大的种对却为铁杆蒿和大针茅, 10个优势物种中各物种与其它9个物种重叠值的平均值最大的为铁杆蒿。

3 讨论

3.1 不同管理方式草地群落生态位宽度分析

生态位宽度是度量植物种群对环境资源利用状况的尺度^[12], 与物种间的相互适应及相互影响密切相关, 种群生态位宽度越大, 则它对环境的适应能力越强。在陕北黄土丘陵区, 不同管理方式下的植被恢复引起草地的物种组成和群落结构发生变化^[14], 同时又促进草地生态系统中物种对资源环境的利用和生态位功能的发挥, 改变草地中主要植物种群的竞争能力及资源占有强度^[15]。

封育是退化草地生态系统恢复和重建的重要手段之一, 草地群落在封育条件下迅速恢复的原因是植物种群拓殖与对群落剩余资源利用能力的增加^{[5, 15]}。本研究显示, 封育管理的草地群落中, 生态位宽度值大于4的植物有6种, 表明种群对资源的占有拓宽, 其中大针茅、达乌里胡枝子、紫花地丁和长芒草的生态位宽度值较大。大针茅是多年生禾草, 需水性及蒸发量较少, 对干旱环境具有良好的适应能力^[22], 是该区域的泛化种, 具有较强的种间竞争能力。封育可促进草地群落盖度增加进而改善土壤水分及土壤养分^[12], 导致高度较小、湿生、耐阴物种紫花地丁生态位宽度拓宽。铁杆蒿由于其成丛分布, 降低了数量优势而导致生态位宽度变窄^[23]。本研究中, 封育群落年限为10年, 处于演替的过渡期, 达乌里胡枝子和大针茅生态位宽度拓宽, 此时群落垂直结构从高到低依次为大针茅、铁杆蒿和达乌里胡枝子, 这与黄土高原典型草原的自然恢复演替推断的第3个阶段相似^[5], 说明退化草地正在发生内因生态演替而适应当地环境。此时群落优势种为达乌里胡枝子、铁杆蒿, 而群落通过自然恢复演替到该阶段需15~20年^[24], 这揭示封育管理可促进该区植被恢复^[16]。达乌里胡枝子+铁杆蒿、大针茅+长芒草是黄土丘陵群落演替的先后两个阶段^[15], 该群落中大针茅和长芒草为伴生种且生态位宽度上升幅度较大, 优势种生态位宽度下降, 表明群落正在向大针茅和长芒草演替。封育管理下物种生态位宽度上升、普遍较大, 铁杆蒿等少数物种生态位宽度下降且幅度较小, 表明该时期的过渡特征造成各物种竞相利用有限资源, 相互释放或压缩生态位, 处于演替中的不稳定时期^[15]。

放牧是陆地生态系统最重要的管理方式之一, 也是合理利用草地与培育改良草地必然涉及的重要问题^[25], 它对植物群落的作用具有两面性, 植物群落随着放牧强度的变化而受到不同程度的影响^[26]。本研究表明, 放牧管理方式下, 生态位宽度大于4的物种数达到最大(表2), 因为本研究中放牧群落属于轻度放牧^[17], 符合适度管理理论^[27]:即适度管理条件下, 物种多样性较大, 群落结构相对稳定。放牧管理下生态位宽度较大的草种较其它群落差异明显, 说明放牧对群落结构及异质性影响较大^[10]。牲畜的采食抑制了优势种赖草的生长, 耐牧草种(长芒草、铁杆蒿等)、耐践踏草种(翻白委陵菜、紫花地丁等)和牲畜不喜食的杂草(刺儿菜)生态位宽度增加, 即降低了优势种的竞争优势^[5], 这样为竞争力较弱物种的生存拓宽了空间, 提高了资源利用率, 增加了群落结构的复杂性^[28]。其次, 家畜在草地的活动协助某些植物传播种子, 促使这些植物水平分布更广, 越有利于种子迅速找到适宜的生存环境^[29], 从而使其生态位拓宽, 如本研究中的长芒草。放牧管理下猪毛蒿和刺儿菜处于优势地位, 紫花苜蓿、长芒草和紫花地丁为伴生种, 与优势种相比, 伴生种的生态位宽度更大, 由此推断, 随着放牧的进行, 群落可能向以赖草、紫花苜蓿和长芒草为优势种群的方向发展, 这表明生境有了明显的变化, 因为赖草、紫花苜蓿和长芒草更适合生长在相对干旱的环境^[15]。由于自身生物学特性, 不同植物对放牧管理的适应能力不同从而导致种群生态位和群落结构发生变化, 放牧演替系列上植物种群生态位的分化过程是草地正向演替的过程, 这与郑伟等^[10]的研究结果一致。

施肥管理下, 土壤中的养分资源增加, 群落盖度明显高于其它管理方式(表1), 一些喜肥物种^[30](阿尔泰狗娃花和达乌里胡枝子)具备更高的生长率, 促进地上生物量和盖度的增加, 导致生态位宽度的增加。达乌里胡枝子因具备固氮能力而生长迅速^[31], 生态位宽度随之拓宽。优势种的快速生长使群落郁闭度增大, 光源获取能力和光竞争能力增强, 导致群落下层不耐阴物种或个体较小物种减少或死亡^[32]。同时, 资源的增加改变了群落内物种的相对竞争能力, 使优势种(阿尔泰狗娃花)地下、地上竞争能力增强^[33]。铁杆蒿生命力极强, 根蘖性强, 能迅速分蘖出枝条, 且具有化感作用^[34], 抑制其它物种的生长, 使其它物种生态位宽度降低。对高寒沙化草地进行的两年施肥研究表明, 群落发生逆向演替, 多样性降低^[11]。也有研究证实了长期施肥使地下养分竞争的强度减弱, 光竞争增强, 使群落结构简单^[35]。本研究显示, 施肥的群落中达乌里胡枝子和阿尔泰狗娃花成为优势物种且生态位宽度最大, 其它物种生态位宽度相对较小, 表明群落将通过演替扩大优势物种的优势地位从而导致群落结构单一。

由于刈割阻止了养分的回归^[36], 使刈割管理的群落中具有固氮能力且抗旱能力较强的达乌里胡枝子和紫花苜蓿成为优势物种。赖草种子于8月上旬成熟, 发生在刈割之前, 所以赖草生态位宽度较大, 与其它管理方式相比, 种子成熟较晚的物种如阿尔泰狗娃花生态位宽度值下降, 根茎型禾草白羊草在草地返青季能快速生长, 成为群落优势种。此外, 刈割导致群落盖度下降, 蒸发增大^[37], 所以耐旱植物生态位宽度整体高于喜阴植物。刈割干扰了群落的自然演替进程, 致使优先占有资源的达乌里胡枝子和紫花苜蓿生态位宽度增加, 其它物种生态位宽度下降, 优势种扩大种群使群落结构单一、多样性降低, 抗逆性较差, 易导致草地退化。灭鼠管理的群落, 由于人为去除食物链上端的动物, 优势物种缺乏天敌的抑制而继续扩大优势地位, 外加铁杆蒿的化感作用^[34], 使猪毛蒿、大针茅和铁杆蒿的生态位宽度值明显高于其它物种。猪毛蒿为该群落的优势物种, 学者认为猪毛蒿群落出现在演替的初始阶段^[23], 此外, 优势种的过优势化易导致群落多样性降低不利于植被恢复^[38], 致使灭鼠的群落中物种数目减少, 其它物种生态位宽度整体偏低。

前人研究表明, 达乌里胡枝子、茭蒿、铁杆蒿、白羊草和草木樨状黄芪(Astragalus melilotoides)等为该区甲等牧草, 旱芦苇、大针茅和长芒草为乙等牧草, 它们为该区的优质牧草^[23]。本研究显示, 封育、放牧、施肥、刈割和灭鼠管理下优质牧草总数分别为5、5、6、8和4种, 刈割群落中优质牧草种类明显多于其它管理方式。放牧管理下仅乙等牧草长芒草生态位宽度较大, 为该群落中的伴生种, 灭鼠管理的群落中生态位宽度较大的牧草仅乙等牧草大针茅, 且为劣势种, 这两种管理方式下其它甲、乙等牧草生态位宽度较低且不为优势种。封育管理的群落中甲等牧草达乌里胡枝子和乙等牧草大针茅为优势种, 且生态位宽度值并列第1, 此外, 乙等长芒草生态位宽度较高。施肥管理下甲等牧草达乌里胡枝子为优势种且生态位宽度增加, 甲等牧草铁杆蒿和乙等牧草长芒草生态位宽度较宽; 刈割的群落中达乌里胡枝子和紫花苜蓿为优势种且生态位宽度较大, 其中, 紫花苜蓿为陕北黄土丘陵区常见优质牧草, 甲等牧草铁杆蒿和白羊草生态位宽度较大。综上, 封育、施肥和刈割管理下, 多种优质牧草生态位宽度较大且多为优势种, 而放牧和施肥的群落仅1种优质牧草为优势种或者生态位宽度较大, 这表明封育、施肥和刈割管理有利于该区优质牧草发展, 其中刈割管理最为明显。

3.2 不同管理方式草地群落生态位重叠分析

生态位宽度较大的物种之间的生态位重叠机会较大^{[39, 40]}, 本研究也得到相似结果。施肥的草地中阿尔泰狗娃花和达乌里胡枝子生态位重叠值最大, 两者的生态位宽度也分居第1位和第2位(表2、表5)。然而在其它管理方式下, 生态位宽度值大的物种并没有出现生态位重叠较大的现象, 表明较高的生态位宽度和较高的生态位重叠之间没有相关性, 以往的研究也得出相似的结论^{[16, 41, 42]}, 这一现象从另外一个角度说明占有较多资源的物种间不存在激烈竞争, 各物种已通过竞争短暂共存, 同时也表明施肥群落中优势种之间竞争激烈, 群落极不稳定。生态位宽度和生态位重叠间是否具线性关系的结论不同, 可能由于研究对象所处的演替阶段决定的, 学者以演替过渡阶段群落为研究对象进行分析发现, 生态位宽度和生态位重叠间不具备线性关系^[11], 而以同一演替阶段或稳定群落的为研究对象则表明生态位宽度和生态位重叠具备一定的线性关系^[12]。不同管理方式下各优势种对生态位重叠差异明显, 由于管理方式不同造成群落组成的不确定性, 以及植物对环境资源存在着激烈的竞争和高的空间异质性^[43]。封育、放牧管理下生态位重叠较高, 这是由于轻度管理去除了优势物种的优势地位, 伴生种得以发展。同时, 围栏封育和轻度放牧可以提高土壤中各类群微生物的生物量, 从而调节和改善土壤营养状况, 促进植物生长^[44]。草地恢复演替过程中各物种长期相互适应, 物种间对环境资源的要求趋于相同, 彼此间通过竞争向下一稳定群落过渡。刈割和灭鼠管理下, 群落结构和区域环境变化, 物种的繁殖策略及自身对环境的适应存在差异, 适应该变化的物种充分利用资源, 少数物种竞争排序上升, 从而导致生态位重叠大于0.90的种对变少。刈割和灭鼠影响草地生态系统的能量流动和物质循环^[37], 优势种生态位宽度和生态位重叠变小, 使个别物种处于优势地位, 降低草地物种多样性, 对草地健康会产生严重干扰。施肥、刈割和灭鼠管理下生态位重叠值小于0.50的种对数较多而生态位宽度大于0.90的种对数较少, 而封育和放牧管理下优势种对生态位重叠值集中于0.70~0.90, 这说明施肥、刈割和灭鼠管理下少数物种间存在激烈竞争, 而封育和放牧管理下多数物种间存在竞争, 群落仍在向稳定群落演替。

4 结论

不同管理方式下主要优势物种生态位宽度不同, 群落处于不同的演替阶段。研究表明, 封育、放牧管理下群落内部竞争激烈, 加速群落向高级阶段演替, 施肥、刈割和灭鼠管理促使群落向结构单一、优势种过优势化的群落演替, 施肥还导致群落发生逆行演替, 不利于植被恢复。施肥管理的群落中种群生态位重叠和生态位宽度之间存在线性关系, 其它管理方式下种群生态位重叠和生态位宽度间不存在线性关系, 是否具备线性关系取决于群落所处的演替阶段。封育、施肥和刈割管理下, 优质牧草数量居多、生态位宽度较大且多为优势种, 这表明封育、施肥和刈割管理有利于该区优质牧草发展, 其中刈割管理最为明显。

The authors have declared that no competing interests exist.

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[31]	靳淑静, 韩蕊莲, 梁宗锁. 黄土丘陵区不同立地达乌里胡枝子群落水分特征及生物量研究. 西北植物学报, 2009, 29(3): 542-547. Jin S J, Han R L, Liang Z S. Water physiological ecology characteristics and community biomass of Lespedeza davurica under different Habitats in Gully Areas of Loess Plateau. Acta Botanica Boreali-Occidentalia Sinica, 2009, 29(3): 542-547. (in Chinese) [本文引用:1]
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[33]	井光花, 程积民, 苏纪帅, 魏琳, 史晓晓, 金晶炜. 黄土区长期封育草地优势物种生态位宽度与生态位重叠对不同干扰的响应特征. 草业学报, 2015, 24(9): 43-52. Jing G H, Cheng J M, Su J S, Wei L, Shi X X, Jin J W. Response of dominant population niche breadths and niche overlaps to various disturbance factors in typical steppe fenced grassland of China’s Loess Plateau region. Acta Pratacultural Science, 2015, 24(9): 43-52. (in Chinese) [本文引用:1]
[34]	王辉, 谢永生, 程积民, 摄晓燕. 基于生态位理论的典型草原铁杆蒿种群化感作用. 应用生态学报, 2012, 23(3): 673-678. Wang H, Xie Y S, Cheng J M, She X Y. Allelopathic effects of Artemisia sacrorum population in typical steppe based on niche theory. Chinese Journal of Applied Ecology, 2012, 23(3): 673-678. (in Chinese) [本文引用:2]
[35]	杨中领, 苏芳龙, 苗原, 钟明星, 肖蕊. 施肥和放牧对青藏高原高寒草甸物种丰富度的影响. 植物生态学报, 2014, 38(10): 1074-1081. Yang Z L, Su F L, Miao Y, Zhong M X, Xiao R. Effects of fertilization and grazing on species richness in an alpine meadow of Qinghai-Xizang Plateau. Chinese Journal of Plant Ecology, 2014, 38(10): 1074-1081. (in Chinese) [本文引用:1]
[36]	章家恩, 刘文高, 陈景青, 施耀才, 蔡燕飞. 不同刈割强度对牧草地上部和地下部生长性状的影响. 应用生态学报, 2005, 16(9): 1740-1744. Zhang J E, Liu W G, Chen J Q, Shi Y C, Cai Y F. Effects of different cutting intensities on above-and underground growth of Stylosanthes guianensis. Chinese Journal of Applied Ecology, 2005, 16(9): 1740-1744. (in Chinese) [本文引用:1]
[37]	曾希柏, 刘更另. 刈割对植被组成及土壤有关性质的影响. 应用生态学报, 2000, 11(1): 57-60. Zeng X B, Liu G L. Effect of cutting on vegetation composition and soil properties. Chinese Journal of Applied Ecology, 2000, 11(1): 57-60. (in Chinese) [本文引用:2]
[38]	许中旗, 李文华, 许晴, 闵庆文, 王英舜, 何旭生. 禁牧对锡林郭勒典型草原物种多样性的影响. 生态学杂志, 2008, 27(8): 1307-1312. Xu Z Q, Li W H, Xu Q, Min Q W, Wang Y S, He X S. Effects of grazing prohibition on species biodiversity of typical steppe in Xilinguole. Chinese Journal of Ecology, 2008, 27(8): 1307-1312. (in Chinese) [本文引用:1]
[39]	Walker B. Conserving biological diversity through ecosystem resilience. Conservation Biology, 1995, 9(4): 747-752. [本文引用:1]
[40]	张林静, 岳明, 张远东, 顾峰雪, 潘晓玲, 赵桂仿. 新疆阜康绿洲荒漠过渡带主要植物种的生态位分析. 生态学报, 2002, 22(6): 969-972. Zhang L J, Yue M, Zhang Y D, Gu F X, Pan X L, Zhao G F. Analysis on the niche of the main plant species of Oasis-deseart E-cotone in Fukang of Xinjiang. Acta Ecologica Sinica, 2002, 22(6): 969-972. (in Chinese) [本文引用:1]
[41]	李瑞, 张克斌, 张生英, 杨晓晖, 乔峰. 宁夏盐池人工封育草原植物生态位研究. 中国水土保持科学, 2006, 4(1): 49-54. Li R, Zhang K B, Zhang S Y, Yang X H, Qiao F. Vegetable niche of enclosed grassland in Yanchi County of Ningxia. Science of Soil and Water Conservation, 2006, 4(1): 49-54. (in Chinese) [本文引用:1]
[42]	陈艳瑞, 尹林克. 人工防风固沙林演替中群落组成和优势种群生态位变化特征. 植物生态学报, 2008, 32(5): 1126-1133. Chen Y R, Yin L K. Community composition and niche change characteristics of dominant species in the wind-breaking and sand -fixing forest, Xinjiang, China. Journal of Plant Ecology, 2008, 32(5): 1126-1133. (in Chinese) [本文引用:1]
[43]	Limb R F. The effects of disturbance in grassland plant communities. Ann Arbor: Oklahoma State University, 2008: 121. [本文引用:1]
[44]	斯贵才, 袁艳丽, 王建, 王光鹏, 雷天柱, 张更新. 围封对当雄县高寒草原土壤微生物和酶活性的影响. 草业科学, 2015, 32(1): 1-10. Si G C, Yuan Y L, Wang J, Wang G P, Lei T Z, Zhang G X. Effects of fencing on microbial communities and soil enzyme activities in Damxung alpine grassland . Pratacultural Science, 2015, 32(1): 1-10. (in Chinese) [本文引用:1]

2011

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... 生态位是指种群在时间、空间的位置以及种群在群落中的地位和功能作用^[1] ...

2011

0.0

谢春平, 方彦, 方炎明. 乌冈栎群落乔木层种群生态位分析. 中国水土保持科学, 2011, 9(1): 108-114, 120.

Xie C

, Fang

, Fang Y

Analysis on the tree stratum niche characteristics of Quercus phillyraeoides communities.

Science of Soil and Water Conservation, 2011, 9(1): 108-114, 120. (in Chinese)

Based on the using importance value as one index of resource state,tree stratus niche characteristics of Quercus phillyraeoides communities distributed in Fujian Jiangshi,Zhejing Kaihua,Guangdong Renhua,Hunan Yuanling,and Guizhou Libo were calculated and analyzed with Levins,Hurtlbert,Pianka and Schoener formulas.The results showed that: 1) As the edificator in the communities,the niche breadth value of Quercus phillyraeoides was larger than other species,with Levins(Bi) and Hurlberts’(Ba) values being 0.678,0.690,0.693,0.682,0.694 and 0.879,0.950,0.967,0.908,0.972 respectively.2) For more than 70% species pair,values of niche overlap were less than 0.6,which indicated that species in the communities were partial to special resource and there were niche differentiation among them;what’s more,niche overlap between the species did not mean the competition,which should happen when the communities went short of resources.3) the distribution proportion of Schoener value( C ih >0.4) was 44.76%,24.09%,33.33%,39.08% and 43.69% respectively in Jiangshi,Kaihua,Renhua,Yuanling,and Libo,which means they were highly similar in the requirement of resource,and we can judge the niche differentiation by the niche similarity.4) Quercus phillyraeoides communities belonged to the stable climax,so the niche of each species in the communities was chosen by the nature for a long term;Quercus phillyraeoides would keep the dominant state unless the human disturb occurrs.

1.Investigation Department of Nanjing Forest Police College,210046;2.College of Forest Resources and Environment,Nanjing Forestry University,210037:Nanjing,China

通过野外群落调查,以物种重要值为生态位计算的资源状态指标,应用Levins公式、Hurtlbert公式、Pianka公式和Schoener公式,对福建将石、浙江开化、广东仁化、湖南沅陵和贵州荔波的乌冈栎群落乔木树种的生态位宽度、生态位重叠和生态位相似性比例进行了计算与分析。结果表明:1)乌冈栎作为群落的建群种,其生态位宽度要大于其他物种,Levins和Hurtlbert生态位宽度值在各群落中分别为0.678、0.690、0.693、0.682、0.694和0.879、0.950、0.967、0.908、0.972。2)从Pianka生态位重叠值来看, N p 0.4的高相似性分布段中,将石、开化、仁化、沅陵和荔波所占比例分别为44.76%、24.09%、33.33%、39.08%和43.69%,相似性比例越高的种对,对资源的需求就具有越高的趋同性,由此可判断群落生态位分化的程度。4)乌冈栎林属于稳定的地形顶级群落,各物种所占据的生态位是自然界长期选择的结果,群落处于动态的稳定状态;在没有外部干扰的情况下,乌冈栎将长期保持优势种的地位。

... 生态位作为物种的生态学和进化生物学特征的反映,同时又与种间的相互适应及相互作用密切相关,已成为评价种间和种内关系及种群在群落中所处地位的重要手段^[2],在环境保护、资源利用、生物多样性及其形成机制、群落演替等方面有着广泛的应用前景^[3] ...

2003

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2002

0.0

... 其中,草地是受人类活动影响最大的陆地生态系统之一,在全球碳循环、涵养水源、水土保持和气候调节中起着重要作用^[4] ...

2013

0.0

陈芙蓉, 程积民, 刘伟, 朱仁斌, 杨晓梅, 赵新宇, 苏纪帅. 不同干扰对黄土区典型草原物种多样性和生物量的影响. 生态学报, 2013, 33(9): 2856-2866.

Chen F

, Cheng J

, Liu

, Zhu R

, Yang X

, Zhao X

, Su J

Effects of different disturbances on diversity and biomass of communities in the typical steppe of loess region.

Acta Ecologica Sinica, 2013, 33(9): 2856-2866. (in Chinese)

Typical steppe is a type of grassland which forms in inland temperate semi-arid climatic conditions, where xerophytic perennial bush grasses, especially Stipa spp., dominate. Grassland ecosystems are one of the largest terrestrial ecosystems affected by human activities. It is important to study the impact of different types of disturbance on the biodiversity and biomass of grasslands ecosystems during restoration and reconstruction work. Exclosures, grazing, fertilization and burning are four major types of anthropogenic disturbance occurring in grassland ecosystems, and have very important impacts on them. To provide a scientific basis for the protection of grassland biodiversity and the sustainable use of grasslands, the influences of different disturbances on the characteristics of above-ground vegetation were studied in a typical steppe in the loess region of China based on the field investigation and monitoring. We established plots representing four different types of treatments: exclosure (E), exclosure plus fertilization (EF), exclosure plus burning (EB) and grazing (G). All plots had the same soil type, topography and hydrological conditions. During the entire experiment, we determined total coverage, vegetation height, individual density, aboveground biomass and diversity of the plant community in each plot. Our results show the dominant vegetation community type of G plots is Agropyron cristatum + Potentilla acaulis + Artemisia sacrorum , a community which is the result of long-term grazing. The dominant vegetation community type of the E plots is Stipa grandis + Poa sphondylodes + Medicago ruthenica , a result of fencing. The dominant vegetation community type of the EF plots is Carex duriuscula + Stipa bungeana + Stipa grandis . The dominant vegetation community type of the EB plots is Artemisia sacrorum + Stipa bungeana + Stipa grandis. The different disturbance regimes strongly influenced community diversity and biomass. To be more specific, total coverage, above-ground biomass and the dominance indices were all at the highest level in the EF treatments in four types of treatments. This may attributed to grass species which play a dominant role in this community. Also, with low evenness and diversity indices, this result was consistent with niche theory which states differences among species in their environmental tolerances, niche requirements, and competitive abilities determine coexistence. Total coverage, height and aboveground biomass were all lowest for the G treatment, while community richness and diversity indices were higher for G than other three treatments. This result supports the intermediate disturbance hypothesis which states that biodiversity will be greatest in communities subjected to moderate levels of disturbance. Only the individual density and evenness index was higher with the E treatment than with the other treatments. Thus we can document the trend for biomass as EF > EB > E > G. These demonstrate long-term exclosure is a severe type of disturbance in grassland ecosystems. Also, the community richness indices ( R and Ma ) showed a certain tendency within these four treatments: G > EF > EB > E and community evenness indices ( J sw and E a ) could be sequenced in the order of E > G > EB > EF. Meanwhile, the order of diversity indices ( H' and D ) was as follows: G > E > EB > EF, while the dominance index was opposite the order of diversity index. Finally, there was negative correlation between community productivity and Shannon-Wiener and Simpson indices, which can be explained by interactions between root and shoot competition.

对黄土区典型草原进行封育+施肥(EF)、封育+火烧(EB)、封育(E)和放牧(G)处理,实地调查分析群落盖度、高度、密度、地上现存量和物种多样性,以研究不同干扰对黄土区典型草原群落物种多样性和生物量的影响.结果表明:在4种干扰类型中,施肥+封育草地群落盖度和地上生物量最高,且优势度指数最高,这与禾本科草占优势地位有关,群落均匀度指数和多样性指数最低,符合"生态位理论";放牧地群落高度、盖度、密度和地上现存量最低,群落丰富度指数和多样性指数最高,支持"中度干扰理论";封育地密度和均匀度指数最高;具体表现为:4种干扰类型地上生物量的变化趋势为封育+施肥＞封育+火烧＞封育＞放牧;说明长时间的封育对草地是一种严重干扰.群落丰富度指数( R 和 Ma )的排列顺序为放牧＞封育+施肥＞封育+火烧＞封育,群落物种多样性指数( H '和 D )的排列顺序为放牧＞封育＞封育+火烧＞封育+施肥,优势度指数与多样性指数相反,群落均匀度指数( J sw 和 Ea )的排列顺序为封育＞放牧＞封育+火烧＞封育+施肥.不同干扰样地群落生产力与Shannon-Wiener和Simpson多样性指数间呈负相关关系,这个结论可以用地上/地下竞争的相互作用来解释.

... 封育可以显著影响草地群落特征,提高退化草地的生产力^[5] ...

... 施肥使高寒草甸植物群落物种数量减少,群落结构趋于简单,物种多样性降低^[5,8] ...

... 刈割在抑制和消除草原灌木、提高草地的利用价值等方面作用明显^[5,9] ...

... 封育是退化草地生态系统恢复和重建的重要手段之一,草地群落在封育条件下迅速恢复的原因是植物种群拓殖与对群落剩余资源利用能力的增加^[5,15] ...

... 本研究中,封育群落年限为10年,处于演替的过渡期,达乌里胡枝子和大针茅生态位宽度拓宽,此时群落垂直结构从高到低依次为大针茅、铁杆蒿和达乌里胡枝子,这与黄土高原典型草原的自然恢复演替推断的第3个阶段相似^[5],说明退化草地正在发生内因生态演替而适应当地环境 ...

... 牲畜的采食抑制了优势种赖草的生长,耐牧草种(长芒草、铁杆蒿等)、耐践踏草种(翻白委陵菜、紫花地丁等)和牲畜不喜食的杂草(刺儿菜)生态位宽度增加,即降低了优势种的竞争优势^[5],这样为竞争力较弱物种的生存拓宽了空间,提高了资源利用率,增加了群落结构的复杂性^[28] ...

2014

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... 放牧通过改变植被结构和土壤理化性质增加生境的异质性,从而造成草地群落植物组分、结构和多样性格局发生变化^[6,7] ...

2003

0.0

... 放牧通过改变植被结构和土壤理化性质增加生境的异质性,从而造成草地群落植物组分、结构和多样性格局发生变化^[6,7] ...

2011

0.0

... 施肥使高寒草甸植物群落物种数量减少,群落结构趋于简单,物种多样性降低^[5,8] ...

2014

0.0

高本强, 袁自强, 王斌先, 高慧, 张荣. 施肥和刈割对亚高山草甸物种多样性与生产力及其关系的影响. 植物生态学报, 2014, 38(5): 417-424.

Gao B

, Yuan Z

, Wang B

, Gao

, Zhang

Effects of fertilization and clipping on species diversity, productivity and their relationship in subalpine meadow.

Chinese Journal of Plant Ecology, 2014, 38(5): 417-424. (in Chinese)

Aims The objective of this study was to determine whether fertilization and clipping would affect species diversity, productivity, and the relationship between species diversity and productivity in a subalpine meadow of China. Methods The experiment was set up as a randomized block design consisting of three levels of fertilization and three intensities of clipping with eight replications, using quadrat size of 0.5 × 0.5 m 2 . The aboveground biomass and species diversity were measured within each quadrat. The relationship between species diversity and productivity were tested by plotting aboveground biomass against species diversity based on linear and non-linear regressions by treatments. Important findings Fertilization and clipping had significant effects on aboveground biomass; community biomass increased with the level of fertilization but decreased with the clipping intensity. Both fertilization and clipping had no apparent effects on species diversity. The relationships between aboveground biomass and species diversity occurred as monotonic, quadratic, or non-correlated depending on fertilization and clipping treatments, meaning that the relationship between species diversity and productivity is not always isotropic and changes with conditions of fertility and level of biomass removal in the community. Thus, productivity is unlikely related to species diversity under conditions of varying fertilization regimes and clipping treatments.

Institute of Arid and Agro-ecology, School of Life Sciences, State Key Laboratory of Grassland and Agro-Ecosystems, Lanzhou University, Lanzhou 730000, China

施肥和刈割分别对植物群落物种多样性和生产力有重要的影响。采用不同施肥水平和刈割频度, 研究了施肥和刈割对亚高山草甸植物群落物种多样性与生产力及其关系的影响。结果显示, 5年的施肥和刈割处理对群落地上生物量均有显著影响, 但对物种多样性影响不显著; 物种多样性与生产力之间的关系因施肥和刈割次数的不同而不同, 有负相关、二次函数关系和不相关等几种类型, 多数为不相关。此结果表明施肥和刈割并不总是一致性地影响群落物种多样性与生产力。因此, 不同施肥和刈割处理下的亚高山草甸植物群落生产力与物种多样性之间并没有确定的关系。

... 刈割在抑制和消除草原灌木、提高草地的利用价值等方面作用明显^[5,9] ...

2013

0.0

郑伟, 董全民, 李世雄, 刘玉. 放牧对环青海湖高寒草原主要植物种群生态位的影响. 草业科学, 2013, 30(12): 2040-2046.

Zheng

, Dong Q

, Li S

, Liu

Effect of grazing on niche of major plant populations in alpine steppe in Qinghai Lake Region.

Pratacultural Science, 2013, 30(12): 2040-2046. (in Chinese)

Alpine steppe is the major vegetation community around Qinghai Lake Region. It is regarded as an important ecological barrier of the Qinghai-Tibetan Plateau and a rich site forage base for yak and sheep production. However, the alpine steppe vegetation degraded by overstocking. Therefore, it’s important to study the effects of grazing on community of alpine steppe around Qinghai Lake Region. In this study, the vegetation under different grazing intensity were investigated, based on grazing trial for 3 years in alpine steppe around Qinghai Lake Region. Levins niche breadth and Pianka niche overlap index were used to calculate niche characteristics of major plant populations under different grazing gradients to explain the mechanism of grazing succession of community. Our results showed that dominant species of community had changed after grazing 3 years. The dominance of plants with good palatability ( Stipa purpurea, Poa sp., Medicago ruthenica , etc.) decreased and the dominance of plants with grazing resistance or bad palatability ( Kobresia humilis, Thermopsis lanceolata , etc.) increased with the increase of grazing intensity. S.purpurea had the widest niche breadth, and after then was Thermopsis lanceolata, with the values being 0.994 and 0.959, respectively. Potentilla multifida and Astragalus polycladus had wider niche breadth because of its stronger environmental adaptation ability. The niche breadths of Elymus nutans and K.cristata under different grazing gradients were narrow, indicating that grazing restricted the growth of high grasses. Species with wider niche breadth had higher niche overlap with other species. The narrower niche overlap could be seen as the result of interspecific differentiation on resource utilization. The major plant populations had niche differentiation result from grazing. With increasing grazing intensity, community with S.purpurea and Poa sp. being the dominant populations may be in degradation direction on community with K.humilis, K.pygmaea and T.lanceolata being the dominant populations, indicating that habitat of community had obviously degraded. Therefore, it’s important to control grazing intensity of rangeland.

1.Graduate College of Qinghai University, Xining 810003, China; 2.Qinghai Academy of Animal and Veterinary Sciences, Xining 810016, China

以环青海湖高寒草原为研究对象,对不同放牧强度下草地植被进行调查,并运用Levins生态位宽度和Pianka生态位重叠指数对不同放牧率梯度下主要植物种群生态位特征进行计算,以期从生态位角度解释植物群落的放牧演替机制。结果表明,经过3年的放牧,群落优势种发生了改变,随着放牧强度的增加,适口性好的植物优势度降低,家畜不喜食或不食的和耐牧的植物优势度增加。紫花针茅生态位宽度最大,披针叶黄华次之,分别为0.994和0.959,多裂委陵菜( Potentilla multifida)和多枝黄芪(Astragalus polycladus)环境适应能力较强,生态位宽度较大。在放牧率梯度上垂穗披碱草(Elymus nutans)和溚草(Koeleria cristata)的生态位宽度较小,说明放牧抑制了高大禾草的层片发育。生态位宽度较大的物种与其他种群间有较大的生态位重叠,生态位重叠度较小是种间对资源需求分化的结果。放牧使主要植物种群生态位发生了分化,随着放牧强度的增加,群落可能从以紫花针茅和早熟禾等为优势种群向以矮嵩草、高山嵩草(K.pygmaea )和披针叶黄华为优势种群的方向发展,表明生境有了明显的退化。因此,控制草地的放牧强度是维持种群健康发展的关键。

... 此外,部分学者探讨了封育、放牧、施肥等管理方式对草地主要植物物种生态位特征的影响,表明放牧管理下适口性好的植物优势度降低,家畜不喜食或不食的和耐牧的植物生态位宽度增加,生态位宽度较大的物种与其它种群间有较大的生态位重叠^[10] ...

... 放牧管理下生态位宽度较大的草种较其它群落差异明显,说明放牧对群落结构及异质性影响较大^[10] ...

... 由于自身生物学特性,不同植物对放牧管理的适应能力不同从而导致种群生态位和群落结构发生变化,放牧演替系列上植物种群生态位的分化过程是草地正向演替的过程,这与郑伟等^[10]的研究结果一致 ...

2011

0.0

陈子萱, 田福平, 郑阳. 施肥对玛曲高寒沙化草地主要植物种生态位的影响. 草地学报, 2011, 19(5): 884-888.

Chen Z

, Tian F

, Zheng

Effects of fertilization on niche of main plant species in Maqu alpine desertification meadow.

Acta Agrestia Sinica, 2011, 19(5): 884-888. (in Chinese)

This study investigated the primary plant species in Maqu alpine desertification meadows using the quadrat sampling method.Specifically,the importance value,niche breadth and niche overlap of the species were reported.Results showed that Stipa aliena Keng was a dominant species of Maqu alpine desertification meadow after fertilization for two years with an average importance value was 0.31.The major weed was Thalictrum alpinum L.with the largest niche breadth(0.993) and also showed the greatest competitive ability and ecological adaptability.The biggest niche overlap value was 0.995 occurred between Scirpus pumilus Vahl and Euphorbia esula L..The niche overlap value between Stipa aliena Keng and Thalictrum alpinum L.was 0.993 ranked as second highest.Fertilization enhanced gramineous grasses growth,causing forb weeds to gradually lose dominance in Maqu alpine desertified meadow.

1. Institute of Biotechnology, Gansu Academy of Agricultural Sciences, Lanzhou, Gansu Province 730070, China; 2. Lanzhou Institute of Animal and Veterinary Pharmaceutics Sciences CAAS, The lanzhou Scientific Observation and Experiment Field Station of Ministry of Agriculture for Ecological System in Loess Plateau Areas, Lanzhou, Gansu Province 730050, China; 3. Pratacultural College of Gansu Agricultural University, Lanzhou, Gansu Province 730070, China

采用样方法对施肥处理的玛曲高寒沙化草地进行了生态位特征的调查,计算了主要植物的重要值、生态位宽度和生态位重叠值。结果表明:对玛曲高寒沙化草地施肥第2年后,草地优势种为异针茅( Stipa aliena Keng),其重要值平均为0.31。高山唐松草( Thalictrum alpinum L.)生态位宽度为0.993,具有最大的竞争力,生态适应性较强,是草地的主要杂草。最大的生态位重叠发生在矮藨草( Scirpus pumilus Vahl)和乳浆大戟( Euphorbia esula L.)之间,生态位重叠值为0.995;其次是异针茅与高山唐松草之间,生态位重叠值为0.993。施肥使禾草类生长旺盛,杂草类的优势地位逐渐失去。

... 施肥使禾草类生长旺盛,杂草类的优势地位逐渐失去,生态位宽度和生态位重叠不具备线性关系^[11] ...

... 对高寒沙化草地进行的两年施肥研究表明,群落发生逆向演替,多样性降低^[11] ...

... 生态位宽度和生态位重叠间是否具线性关系的结论不同,可能由于研究对象所处的演替阶段决定的,学者以演替过渡阶段群落为研究对象进行分析发现,生态位宽度和生态位重叠间不具备线性关系^[11],而以同一演替阶段或稳定群落的为研究对象则表明生态位宽度和生态位重叠具备一定的线性关系^[12] ...

2014

0.0

李中林, 秦卫华, 周守标, 张纪兵, 汪贞, 王运静. 围栏封育下华北半干旱草原植物生态位研究. 草地学报, 2014, 22(6): 1186-1193.

Li Z

, Qin W

, Zhou S

, Zhang J

, Wang

, Wang Y

Study on plant niche under fencing measures in the semiarid grassland of North China.

Acta Agrestia Sinica, 2014, 22(6): 1186-1193. (in Chinese)

In order to find the plant niche pattern of grassland in the semi-arid grassland of North China, a 100 m×100 m enclosure fixed sampling plot in the Hongsongwa Natural Reserve of Chengde was set up, and the fencing measure area and continuous grazing area were studied with the quadrat method.The niche breadths, niche overlaps and niche proportional similarities of plants were calculated in both areas using the theory of niche. The results showed that the niche breadth of Carex lanceolata Boott was the largest in both tested areas.The niche overlaps among the species with broad niche breadths were much greater, such as Carex lanceolata , Artemisia tanacetifolia , Sanguisorba officinalis , Ranunculus japonicas , Polygonum viviparum . The niche proportional similarity among these species with broad niche breadths was much greater,whereas the niche proportional similarity among the species with small niche breadths was lower.These results showed that there were linear relationships between niche breadths and niche overlaps, as well as niche breadths and niche proportional similarities.

1. College of Life Sciences, Anhui Normal University, Wuhu, Anhui Province 241000, China; 2. Nanjing Institute of Environmental Sciences, Ministry of Environmental Protection, Nanjing, Jiangsu Province 210042, China; 3. Hongsongwa Natural Reserve, Chengde, Hebei Province 068450, China

为查明围栏封育条件下华北半干旱草原植物生态位格局及变化,于河北坝上地区红松洼国家级自然保护区设置100 m×100 m围栏监测固定大样地,采用样方法对封育区和放牧区植被生长状况进行调查,运用生态位理论对围栏内外主要植物的生态位宽度、生态位重叠值和生态位相似比例进行测算.结果表明:披针叶苔草( Carex lanceolata )在围栏内外的生态位宽度均为最大.披针叶苔草、裂叶蒿( Artemisia tanacetifolia )、地榆( Sanguisorba officinalis )、毛茛( Ranunculus japonicus )、珠芽蓼( Polygonum viviparum )等生态位宽度较大物种之间具有较高程度的生态位重叠.这些物种的生态位相似比例也较高;而生态位宽度较小的物种其生态位相似比例较小.表明生态位宽度与生态位重叠值、生态位宽度与生态位相似比例之间存在一定的线性关系.

... 封育管理下植物群落生态位宽度差异明显,生态位重叠和种群生态位宽度之间存在一定的线性关系^[12] ...

... 1 不同管理方式草地群落生态位宽度分析生态位宽度是度量植物种群对环境资源利用状况的尺度^[12],与物种间的相互适应及相互影响密切相关,种群生态位宽度越大,则它对环境的适应能力越强 ...

... 封育可促进草地群落盖度增加进而改善土壤水分及土壤养分^[12],导致高度较小、湿生、耐阴物种紫花地丁生态位宽度拓宽 ...

2014

0.0

侯宪宽, 董全民, 施建军, 李世雄, 郑伟, 宋磊. 相同建植年限2种类型人工草地群落结构及物种多样性研究. 草地学报, 2014, 22(5): 961-965.

Hou X

, Dong Q

, Shi J

, Li S

, Zheng

, Song

Structural feature and biodiversity of plant community in the cultivated grassland s of two seeding methods with the same planting fixed number of year.

Acta Agrestia Sinica, 2014, 22(5): 961-965. (in Chinese)

To study the different stabilities of cultivated grassland communities between single seeding and mixed seeding methods in 2009, the structural features and biodiversities of plant communities in the cultivated grasslands in Dawu area were investigated. The results showed that the above-ground biomasses of cultivated grasslands had not significant difference between single seeding and mixed seeding methods in 2009. The proportions of Gramineae had not significant difference between single seeding and mixed seeding for the component of functional group and important value of grassland vegetation. The proportions of both Leguminosae and Cyperaceae in the cultivated grassland of single seeding were lower than that in the cultivated grassland of mixed seeding, whereas others were significant higher. The indexes of species richness and Simpson were significant difference between two seeding methods ( P

1. Qinghai university, Xining, Qinghai Province 810016, China; 2. Qinghai Academy of Animal and Veterinary Science, Xining, Qinghai Province 810016, China

为研究相同建植年限单播、混播2种播种方式下，人工草地群落的稳定性，分别对大武地区2009年单播、混播人工草地群落结构和物种多样性进行分析。结果表明：2009年单、混播人工草地，群落地上生物量未出现显著差异；单播与混播相比，草地植被功能群组成与物种重要值中，禾本科所占比例未出现差异，豆科与莎草科所占比例较低，但杂类草所占比例高于混播草地；物种丰富度指数、Simpson 指数均存在显著差异（ P

... 前人对陕北黄土丘陵区草地的研究,主要集中在群落结构,土壤理化性质,封育、火烧管理、播种方式对植被恢复的影响等方面^[13,14] ...

2008

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邵新庆, 石永红, 韩建国, 王赟文, 王堃. 典型草原自然演替过程中土壤理化性质动态变化. 草地学报, 2008, 16(6): 566-571.

Shao X

, Shi Y

, Han J

, Wang Y

, Wang

Dynamics of soil physicochemical properties during the natural restoration and succession of typical steppe in Inner Mongolia Autonomous Region.

Acta Agrestia Sinica, 2008, 16(6): 566-571. (in Chinese)

A field experiment was conducted in a degraded area of typical steppe ecotype in Balinyou Banner,Inner Mongolia Autonomous Region,China to reveal the dynamics of soil physicochemical properties,using a space series method in stead of time course method,during natural restoration and succession after having been removed human activities by fencing.The results show that enclosure greatly affected the soil water content with an increasing trend,especially in surface soil layer 0~5 cm.During the self-organization restoration of typical steppe community,organic matter,total N,available N,and available K increased significantly( P P -3 and 1.25 g·cm -3 after 6 year and 10 year restoration,respectively,and was significantly lower in comparison with the early restoration stage( P <0.05).

1. Department of Grassland Science, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China; 2. Institute of Animal Science, Shanxi Academy of Agricultural Science, Taiyuan, Shanxi Province 030032, China

以内蒙古巴林右旗退化典型草原为研究对象,采用空间序列代替时间序列的方法,探讨围封条件下,退化典型草原自然恢复过程中土壤物理性质及养分的动态变化。结果表明:围封对典型草原土壤含水量产生深刻影响,土壤水分含量呈增加趋势,增加最明显的是土壤表层0~5 cm;典型草原群落自然恢复过程中,土壤有机质、全氮、速效氮、速效钾增加极显著( P P P <0.05)。

... 前人对陕北黄土丘陵区草地的研究,主要集中在群落结构,土壤理化性质,封育、火烧管理、播种方式对植被恢复的影响等方面^[13,14] ...

... 在陕北黄土丘陵区,不同管理方式下的植被恢复引起草地的物种组成和群落结构发生变化^[14],同时又促进草地生态系统中物种对资源环境的利用和生态位功能的发挥,改变草地中主要植物种群的竞争能力及资源占有强度^[15] ...

2014

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史晓晓, 程积民, 于飞, 朱仁斌, 赵新宇. 云雾山天然草地30年恢复演替过程中优势草种生态位动态. 草地学报, 2014, 22(4): 677-684.

Shi X

, Cheng J

, Yu

, Zhu R

, Zhao X

Niche dynamics of dominant species during the 30 years restoration process of natural grassland in Yunwu Mountain.

Acta Agrestia Sinica, 2014, 22(4): 677-684. (in Chinese)

In order to explore the niche dynamics of dominant species during 30 years restoration process of natural grassland in Yunwu Mountain, the ecological niches of the main species in different enclosure years were calculated using Levin's and Pianka's indices, based on the field survey data got by "quadrat method". Results showed that the species composition and community types differed among the grasslands of different enclosure years. The niche breadths of Heteropappus altaicus , Stipa grandis , Potentilla bifurca and Thymus mongolicus , which appeared in the grasslands of five treatments, were larger than that of other species. Stipa bungeana that used to be a dominant species of Yunwu Mountain with large niche breadth was not found in the quadrats of 30-year enclosure grassland. The species with largest niche breadth in grasslands of enclosure 5-year, 9-year, 14-year, 18-year and 30-year were Stipa bungeana , Artemisia gansuensis , Artemisia scoparia , Stipa grandis and Stipa grandis , respectively. The niche breadth of dominant species fluctuated with the increase of enclosure years. The niche breadth of Stipa grandis showed "up-down-up" trend along with the increasing of enclosure years. The niche breadth of Stipa bungeana initially declined then increased after 18-year enclosure.Theniche breadth of Stipa przewalskyi , which appeared only in 30-year enclosure plots, ranked only second to Stipa grandis . There was no a linear relationship between the niche overlap and niche breadth of tested species in the grasslands at different enclosure years. The average value of niche overlap indices was the largest in 9-year enclosure grassland. The grassland ecosystem was gradually restored with long time enclosure. Meanwhile, interspecific competition was also increased.

1. College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi Province 712100, China; 2. Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling, Shaanxi Province 712100, China; 3. College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi Province 712100, China; 4. College of Forestry, Northwest A&F University, Yangling, Shaanxi Province 712100, China

为探究云雾山天然草地30年恢复演替过程中优势草种的生态位动态，通过典型样方调查，运用Levins和Pianka公式分别对封育5年、9年、14年、18年和30年天然草地的主要物种生态位进行了分析。结果表明：不同封育年限草地的物种组成与群落类型具有明显差异，阿尔泰狗哇花（ Heteropappus altaicus ）、大针茅（ Stipa grandis ）、二裂委陵菜（ Potentilla bifurca ）和百里香（ Thymus mongolicus ）4个种群生态位总宽度较大，且在5个不同封育年限草地均有出现。云雾山原建群种长芒草（ Stipa bungeana ）生态位宽度也较大，但在封育30年样方中未发现其分布。不同封育年限各物种生态位宽度排序和其总宽度排序并不相同，封育5年、9年和14年的草地中生态位宽度最大的分别是长芒草、甘肃蒿（ Artemisia gansuensis ）和猪毛蒿（ A.scoparia ），封育18年和30年草地大针茅最大。随着封育年限增加，优势物种的生态位宽度出现波动，大针茅的生态位宽度随封育年限增加呈现“升-降-升”的动态变化，封育5~18年，长芒草生态位宽度变化表现为先降后升，甘青针茅（ S.przewalskyi ）只在封育30年样地出现，但其生态位宽度仅次于大针茅。种群间生态位重叠与不同封育年限草地种群生态位宽度无线性关系，封育9年草地种群间的生态位重叠指数均值最大，封育14年和30年草地的生态位重叠指数均值呈递增趋势。随着封育年限的增加，草地生态系统逐渐得到恢复，种间竞争也随之增加。

... 对草地优势种群生态位特征的研究仅局限于不同封育年限且主要集中在宁夏云雾山自然保护区^[15,16] ...

... 达乌里胡枝子+铁杆蒿、大针茅+长芒草是黄土丘陵群落演替的先后两个阶段^[15],该群落中大针茅和长芒草为伴生种且生态位宽度上升幅度较大,优势种生态位宽度下降,表明群落正在向大针茅和长芒草演替 ...

... 封育管理下物种生态位宽度上升、普遍较大,铁杆蒿等少数物种生态位宽度下降且幅度较小,表明该时期的过渡特征造成各物种竞相利用有限资源,相互释放或压缩生态位,处于演替中的不稳定时期^[15] ...

... 放牧管理下猪毛蒿和刺儿菜处于优势地位,紫花苜蓿、长芒草和紫花地丁为伴生种,与优势种相比,伴生种的生态位宽度更大,由此推断,随着放牧的进行,群落可能向以赖草、紫花苜蓿和长芒草为优势种群的方向发展,这表明生境有了明显的变化,因为赖草、紫花苜蓿和长芒草更适合生长在相对干旱的环境^[15] ...

2013

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张晶晶, 许冬梅. 宁夏荒漠草原不同封育年限优势种群的生态位特征. 草地学报, 2013, 21(1): 73-78.

Zhang J

, Xu D

Niche characteristics of dominant plant populations in desert steppe of Ningxia with different enclosure times.

Acta Agrestia Sinica, 2013, 21(1): 73-78. (in Chinese)

The vegetation of unenclosed and enclosed desert steppes were investigated after three, four, five, six, and seven years using the method of spatial sequence replacing time series. Niche breadth and overlap indices were used to measure the niche characteristic of dominant plant populations. Results showed that the niche breadth of plant population changed after enclosure. In the 0-year fenced grassland, the niche breadth of Salsola pestifer was the highest one. The niche breadth of Stipa breviliora and Lespedeza potaninii were the largest in 7-year fenced grassland. The niche breadth of Pennisetum centrasiaticum was larger than that of other species in different fencing years. The niche breadth of dominant species narrowed with increasing fencing years, whereas that of other species broadened. The population overlapping index of 0-year fenced grassland was the lowest one and that of 5-year fenced grassland was the highest. Species having high niche breadth didn’t have large niche overlap with other species. There was no relationship between niche breadth and niche overlap of dominant species.

1. Yinchuan Agricultural and Technical Extension and Service Center, Yinchuan, Ningxia 750004, China; 2. College of Agronomy, Ningxia University, Yinchuan, Ningxia 750021, China; 3. Breeding Base of State Key Laboratory for Preventing Land Degradation and Ecological Restoration, Ningxia University, Yinchuan, Ningxia 750021, China

以宁夏荒漠草原为研究对象,采用空间梯度代替时间梯度的方法,对不同封育年限及未封育草地的植被进行调查,并运用生态位宽度和生态位重叠指数对不同恢复演替阶段优势种群的生态位特征进行计测。结果表明:草地封育后,植物种群的生态位宽度发生变化,未封育草地以一年生植物刺蓬( Salsola pestifer )的生态位宽度最大,短花针茅( Stipa breviliora )和牛枝子( Lespedeza potaninii )种群的生态位宽度均以封育7年的草地最高,分别为3.153和4.058,中亚白草( Pennisetum centrasiaticum )种群的生态位宽度在各封育年限草地及未封育草地中均较高,是该区域的泛化种。封育草地恢复演替过程中种群之间生态位重叠总体较高,大多物种间生态位重叠指数在0.4~0.8之间;其中,未封育草地的种群重叠指数较低,封育5年的草地种群重叠指数最高。不同封育年限草地中生态位宽度最大的物种不一定和其他的物种有最大的重叠值,植物群落较高的生态位重叠和种群生态位宽度之间不存在线性关系。

... 对草地优势种群生态位特征的研究仅局限于不同封育年限且主要集中在宁夏云雾山自然保护区^[15,16] ...

... 此时群落优势种为达乌里胡枝子、铁杆蒿,而群落通过自然恢复演替到该阶段需15~20年^[24],这揭示封育管理可促进该区植被恢复^[16] ...

... 然而在其它管理方式下,生态位宽度值大的物种并没有出现生态位重叠较大的现象,表明较高的生态位宽度和较高的生态位重叠之间没有相关性,以往的研究也得出相似的结论^[16,41,42],这一现象从另外一个角度说明占有较多资源的物种间不存在激烈竞争,各物种已通过竞争短暂共存,同时也表明施肥群落中优势种之间竞争激烈,群落极不稳定 ...

2012

0.0

方楷, 宋乃平, 魏乐, 安慧. 不同放牧制度对荒漠草原地上生物量及种间关系的影响. 草业学报, 2012, 21(5): 12-22.

Fang

, Song N

, Wei

, An

The effect of different grazing systems on aboveground biomass and interspecific relationships in desert steppe.

Acta Pratacultural Science, 2012, 21(5): 12-22. (in Chinese)

采用围栏放牧控制试验，研究了不同放牧强度和放牧方式对封育９年荒漠草原地上生物量及种间关系的影响。结果显示，１）放牧强度对生长季不同时期牧草地上生物量的影响不同，中度自由放牧小区的牧草地上生物量在整个生长季都高于封育小区；２）环境条件对牧草地上生物量的影响较大，在光热水等资源充足时，自由放牧区３种牧压梯度下的牧草地上生物量均高于封育禁牧小区，当遭遇高温干旱胁迫时，自由放牧区的牧草地上生物量的增长量均比封育禁牧小区低，中度轮牧草场表现出较好的抗胁迫能力；３）放牧能够减小荒漠草原年内牧草地上生物量的时间变异，而其空间变异对不同放牧制度的响应较为复杂，在不同强度、不同方式以及植被生长季的不同时期都有所不同；４）轻度自由放牧不会改变植物的种间关系和群落之间的关系，而重度自由放牧不仅加剧了群落间的资源竞争，还会引起研究区３种群落发生不同程度的逆向演替，中等强度的４区轮牧方式为研究区最优的放牧模式，它一方面减缓了群落界面上的资源竞争，另一方面促进了本氏针茅群落的顺行演替。以上结果表明，合理地调控人类放牧制度能够促进草地生态系统功能，从而起到恢复和保护草原的作用。

... d)^-1,属轻度放牧^[17] ...

... 本研究表明,放牧管理方式下,生态位宽度大于4的物种数达到最大(表2),因为本研究中放牧群落属于轻度放牧^[17],符合适度管理理论^[27]:即适度管理条件下,物种多样性较大,群落结构相对稳定 ...

1994

0.0

马克平, 刘玉明. 生物群落多样性的测度方法. 生物多样性, 1994(4): 231-239.

Ma K

, Liu Y

Measurement method of biological community diversity. Biological Diversity, 1994(4): 231-239. (in Chinese)

... 1 重要值计算物种重要值(IV)^[18]: ...

1968

0.0

... 2 生态位宽度测定 Levins生态位宽度^[19]: ...

... 生态位总宽度B^[19]: ...

1973

0.0

... 3 生态位重叠值测定 Pianka生态位重叠^[20]: ...

2012

0.0

汤景明, 艾训儒, 易咏梅, 李玲, 徐红梅, 宋亚丽. 鄂西南木林子常绿落叶阔叶混交林恢复过程中优势树种生态位动态. 生态学报, 2012, 32(20): 6334-6342.

Tang J

, Ai X

, Yi Y

, Li

, Xu H

, Song Y

Niche dynamics during restoration process for the dominant tree species in montane mixed evergreen and deciduous broadleaved forests at Mulinzi of southwest Hubei.

Acta Ecologica Sinica, 2012, 32(20): 6334-6342. (in Chinese)

The niche dynamics during natural restoration process of dominant tree species in montane mixed evergreen and deciduous broadleaved forests at Mulinzi of Southwest Hubei were analyzed by means of Shannow-wiener niche breadth index and Pianka niche overlap index. The results showed that the total breadth of niche of Carpinus fargesii, Cornus kousa var. Chinensis and Cycloblanopsis glauca were higher and theses tree species were found in all five restoration stages. Weigela japonica var. sinica, Carpinus fargesii, Cornus kousa var. Chinensis, Betula luminifera and Ilex wilsonii were the species with the largest niche breadth for the restoration stage of 14, 35, 60, 85 and 110 years respectively. There was a general trend that the niche breadth of dominant deciduous tree species decreased with increasing degree of community restoration, while that of dominant evergreen tree species was on the contrary. When the community restored to its climax stage, the niche of evergreen species in tree layer was close to that of deciduous trees, and that of evergreen species in shrub layer occupied a larger niche; this was a spatial pattern for better sharing of natural resources. With increasing restoration degree of community, the niche overlap between dominant deciduous tree species and other tree species had a trend of fluctuant decrease; while that of dominant evergreen tree species had a trend of fluctuant increase; and the niche overlap among all tree species in communities had a tendency of slightly waved decrease. The results showed that higher niche overlap among the early-succession species with same or similar life form meant a similar or competing requirement on resources. The increase of niche overlap among the late-succession species and other tree species represented a horizontally spatial overlap but vertically spatial differentiation; this is a full use mechanism of different tree species regarding limited resources in their environment.

运用Shannow-wiener生态位宽度指数和Pianka生态位重叠指数,分析了鄂西南木林子常绿落叶阔叶混交林恢复过程中优势树种生态位动态。结果表明:大穗鹅耳枥( Carpinus fargesii )、四照花( Cornus kousa var. Chinensis )、青冈( Cycloblanopsis glauca )生态位总宽度较大,且在5个不同恢复时期均有分布。恢复期14a、35a、60a、85a和110a生态位宽度最大的树种分别为白马桑( Weigela japonica var. sinica )、大穗鹅耳枥、四照花、光皮桦( Betula luminifera )和尾叶冬青( Ilex wilsonii )。随着群落的恢复,优势落叶树种生态位宽度表现出下降趋势,优势常绿树种则呈上升趋势。当恢复到顶极群落阶段,乔木层常绿和落叶树种生态位接近,灌木层常绿灌木占据较大生态位。随着群落的恢复,优势落叶树种与其它树种的生态位重叠值呈波动性下降趋势,优势常绿树种表现为波动性上升趋势,群落全部树种间生态位重叠程度呈小幅度波动性下降趋势。相同或相似生活型的演替早期种间的高生态位重叠,意味着种间对资源利用的相似性和竞争关系,演替后期种与其它树种间的生态位重叠的增加,意味着不同生活型树种在水平空间重叠而在垂直空间分化,这是不同树种对有限环境资源充分利用的一种机制。

... 种群间生态位重叠指数的平均值=样地内优势物种间生态位重叠值总数/总种对数^[21] ...

2010

0.0

吴建波, 包晓影, 李洁, 赵念席, 高玉葆. 不同围封年限对典型草原群落及大针茅种群特征的影响. 草地学报, 2010, 18(4): 490-495.

Wu J

, Bao X

, Li

, Zhao N

, Gao Y

Influence of fencing duration on community and population of Stipa grand is in a typical steppe.

Acta Agrestia Sinica, 2010, 18(4): 490-495. (in Chinese)

Stipa grandis steppe is the common stable,representative form of typical steppes in the Inner Mongolia plateau.It is not only an important pasture for Inner Mongolia,but also an important green protective windbreak for Beijing-Tianjin area,and has considerable ecological and economic importance.Recently,the area of degraded S.grandis steppe has rapidly expanded due to increased human disturbance and animal overgrazing.The restoration of degraded grassland is of prime importance in restoration ecology.Most studies have focused on the variation of the vegetation and soil characteristics after restoration with little research attention on the restoration of constructive species.In fact,it was considered that restoring vegetation of constructive species could be sustained by its own growth,which was the key influence on the success of the restoration.In the present study,we used the S.grandis populations in the continuous grazing pasture as a control,and selected fencing S.grandis populations at different times as research objects that had been fenced for 4 years,9 years and 29 years,respectively.We investigated the fencing times affecting the variations of the S.grandis population and communities in the restoration process using a quadrat survey method.Results showed that fencing had an impact on the communities and the populations of S.grandis during grazing.The diversity and the number of species of community increased with fencing time compared to that in the grazing plot.After being fenced for 9 years,the structure and component of the fenced community was similar to that of the original community.The number of perennial forbs and shrubs and semi-shrubs increased in the site fenced for 29 years.The population and morphological characters of S.grandis increased with fencing time and then decreased after being fenced for 9 years.Features of S.grandis in plot fenced for 29 years were significantly lower than those in plots fenced for 9 years.The reproductive allocation of S.grandis also increased with fencing time then decreased after fenced for 9 years.The specific leaf area decreased with fencing time,but the mass-based leaf nitrogen concentration decreased with fencing time and then increased after being fenced for 9 years.Results suggested that long term fencing had a negative impact on the growth and development of plant species and community when the pasture was in recovery after being fenced for 9 years.

College of life science, Nankai University, Tianjin 300071, China

为研究围封时间对退化草地恢复过程中的建群种种群特征以及群落特征的影响,于2008年7月以自由放牧的草地群落和大针茅( Stipa grandis P.Smirn)种群为对照,选取围封不同年限(围封4年、围封9年和围封29年)的草地群落进行样方调查,分析围封不同年限后植物群落和大针茅种群特征的变化,以期为退化草地建群种的恢复提供理论基础。结果表明:不同围封年限对植物群落和大针茅种群特征存在显著影响;随着围封年限的延长群落多样性和物种数目逐渐增加,围封到9年后,群落优势种和结构组成与原生境的相似,在围封29的样地中多年生杂类草和小灌木或半灌木种类增加;建群种大针茅种群特征和个体形态性状如生殖枝高度、营养枝长度和营养枝叶鞘长度等随着围封年限的延长呈增加趋势,围封9年后呈降低趋势,大针茅繁殖分配的变化趋势与形态特征变化趋势相似;大针茅比叶面积随着围封年限的延长呈逐渐降低的趋势,而叶片氮含量呈先降低后增加的趋势。这表明长期完全围封会对大针茅种群的更新存在负面影响。

... 大针茅是多年生禾草,需水性及蒸发量较少,对干旱环境具有良好的适应能力^[22],是该区域的泛化种,具有较强的种间竞争能力 ...

2006

0.0

唐龙, 梁宗锁, 杜峰, 郝文芳. 陕北黄土高原丘陵区撂荒演替及其过程中主要乡土牧草的确定与评价. 生态学报, 2006, 26(4): 1165-1175.

Tang

, Liang Z

, Du

, Hao W

Vegetation succession of arable old land after being aband oned in Loess Plateau hilly region & ascertaining dominant native herbages in the process, analyzing their chemical nutrient composition.

Acta Ecologica Sinica, 2006, 26(4): 1165-1175. (in Chinese)

A 2-year experiment was carried out in the Loess Plateau to better understand vegetation succession of arable old land after being abandoned in Loess hilly region. Based on 2 kinds of ways, one was quantitative classification using system clustering, the other was abandoned year. Again with the overall understood of 25 sample plots research, the result showed that: from 1 to 6 years, annual weeds community →annual weeds + tuft grass community →annual weeds + perennial herbage community or rhizome grass →from 7 to 16 years, perennial herbage community →perennial grass+ undershrub community →from 17 to 42 years, rhizome tuft grass + undershrub community or undershrub + perennial grass community →undershrub community or perennial grass + tuft grass community. The representative communities were: Artemisia scoparia Waldstet. et kit community or A.scoparia Waldstet. et kit + Stipa bungeana Trin. community → A.scoparia Waldstet. et kit + Artemisia sacrorum Leded. community (or Agropyron cristatum(L.)Gaertn community) →Artemisia sacrorum Leded. community → A.scarorum Ledeb. + Lespedeza var.dahurica (Laxm.)Schindl community → Bothriochloa ischaemum (L.)Keng + Artemisia sacrorum Leded. community Or Lespedeza var.dahurica (Laxm.)Schindl+ Artemisia sacrorum Leded. community or Artemisia sacrorum Leded .+ Poa sphondylodes Trin.et Bge community. In order to restore the degraded environment in the arid zone, it was important to know how to collocate kinds of pastures with wild grasses. There is a new way: first, based on the result of the investigation into succession, all kinds of wild grasses were arranged in order of their important values, 1～35th herbage was warranted that being able to yield more quantity production than from 36 to the last grass according with the model of important value, this character was the most important not only for the ecological benefit but also for the economic effectiveness; second, according as the result of palatability experiment, 23 kinds of pastures were selected from the 1～35th grasses to be analyzed their chemical nutrient composition, then, they were graded excellent, fine, good and inferior by the score that gained appraisal by chemical nutrient composition in accordance with the pasture’s quality standard; third, these kinds of pasture community’s ecological benefit was analyzed, then, they were graded excellent, fine, good and inferior too; ultimately, over efficacy of 23 kinds of herbage community was ascertained. To summarize: 23 kinds of pastures were classified into 3 groups according to their site quality of locality in the community in the succession process. One was constructive or dominant species in the period of succession process, but in the other times there were not these herbages, such as Sophora vicifolia Hance, Phragmitas communis Trin; Two was subdominant or companion species in the whole period of succession process, such as Gueldenstaedtia multiflora Bunge, Potentilla bifurca L .; Three was those grasses that transform their site quality of locality in the community in the succession process from constructive or dominant species into subdominant or companion species, or reverse, for example Lespedeza var. dahurica (Laxm.)Schindl, Bothriochloa ischaemum(L.)Keng. Besides, chemical nutrient compositions of these pastures have shown much variation, so, we should be attach importance to this phenomenon. When these conclusions being have applied, it appears important to repair vegetation based on the community structure in the succession process of different abandoned lands, the different pastures that should have overwhelming chemical nutrient composition will be selected from the grasses in the corresponding nature communities.

用系统聚类、撂荒年限两种方法对陕北黄土高原丘陵区撂荒演替序列进行分析，结果基本一致：1～6a,1年生杂草类群落→1年生杂草类＋丛生禾草群落→1年生杂草类＋根茎禾草群落或多年生草本群落→7～16a,多年生草本群落→多年生草本＋小灌木群落→17～42a：根茎丛生型禾草＋小灌木群落或小灌木＋多年生草本群落→小灌木群落或多年生草本＋丛生禾草群落，代表性群落依次为猪毛蒿( Artemisia scoparia Waldstet. et kit)群落或猪毛蒿＋长芒草( Stipa bungeana Trin .)群落→猪毛蒿＋铁杆蒿( Artemisia sacrorum Leded.)群落或冰草( Agropyron cristatum (L.)Gaertn)群落→铁杆蒿群落→铁杆蒿＋达乌里胡枝子( Lespedeza var. dahurica (Laxm.)Schindl)群落→白羊草( Bothriochloa ischaemum (L.)Keng)＋达乌里胡枝子群落或达乌里胡枝子＋铁杆蒿群落或铁杆蒿＋硬质早熟禾( Poa sphondylodes Trin.et Bge)群落。在此基础之上，提出将各物种在演替过程中重要值之和按大小排序，对前35位草种经适口性试验初步筛选后进行以粗蛋白、粗纤维等为指标的化学成分及以有效植被盖度为指标的生态效益的分析、评价，并依据两种评价结果对陕北黄土高原主要乡土牧草进行了综合评定，得出黄土高原23种乡土牧草具备较高的改良潜质，分为4类，主要归属于豆科(Leguminosae)、禾本科(Gramineae)、菊科(Compositae)等，并进一步探讨了黄土高原人工草场改良过程中不同荒地上草种的合理搭配。

... 铁杆蒿由于其成丛分布,降低了数量优势而导致生态位宽度变窄^[23] ...

... 猪毛蒿为该群落的优势物种,学者认为猪毛蒿群落出现在演替的初始阶段^[23],此外,优势种的过优势化易导致群落多样性降低不利于植被恢复^[38],致使灭鼠的群落中物种数目减少,其它物种生态位宽度整体偏低 ...

... 前人研究表明,达乌里胡枝子、茭蒿、铁杆蒿、白羊草和草木樨状黄芪(Astragalus melilotoides)等为该区甲等牧草,旱芦苇、大针茅和长芒草为乙等牧草,它们为该区的优质牧草^[23] ...

2005

0.0

杜峰, 山仑, 陈小燕, 梁宗锁. 陕北黄土丘陵区撂荒演替研究——撂荒演替序列. 草地学报, 2005, 13(4): 328-333.

, Shan

, Chen X

, Liang Z

Studies on the vegetation succession of aband oned farmland in the Loess Hilly Region of Northern Shaanxi——Succession series after being aband oned.

Acta Agrestia Sinica, 2005, 13(4): 328-333. (in Chinese)

Using system clustering to divide the secondary successive of the abandoned farmland in the loess hilly regions of northern Shaanxi province,the similarity of lengths of years and standing conditions of the abandoned farmlands were discerned.Combining the above discernment with the quantitative ordination of DCA,the abandoned farmland successive phases and series were affirmed.The successive phases are as follows: annual weeds Artemisia scoparia+other annual weeds association→annual weeds A.scoparia assocaiation→annual weeds A.scoparia Waldstet kit+perennial herbage or undershrub assocaiation→rhizoma grass Agropyron cristatum (L.)association→perennial herbage or tuft grass+annual weeds association→perennial herbage association→undershrub Lespedeza davurica association→perennial herbage + undershrub or thick tuft grass association→short rhizome and thick tuft grass association.

Institute of Soil and Water Conservation, Chinese Academy of Science;State Key Laboratoryof Soil Erosion and Dryland Farming on the Loess Plateau;Northwest Sci-techUniversity of Agriculture and Forestry, Yangling, Shaanxi Province, 712100, China

用系统聚类法划分陕北黄土丘陵区撂荒地的次生演替阶段,可以定量的认识不同年限、立地条件下撂荒地群落的相似性,结合DCA数量排序确定撂荒地的演替阶段或序列。其撂荒演替的各阶段分别为:一年生杂类草猪毛蒿( Artemisia scoparia )+其它杂类草群丛→一年生杂类草猪毛蒿群丛→一年生杂类草猪毛蒿+多年生草种或小灌木的共优群丛→根茎禾草冰草( Agropyron cristatum )群丛→多年生草本或丛生禾草+一年生杂类草群丛→多年生草本群丛→小灌木达乌里胡枝子( Lespedeza davurica )群丛→多年生草本+小灌木或密丛型禾草群丛→短根茎密丛型禾草白羊草( Bothriochloa ischaemum )群丛。

... 此时群落优势种为达乌里胡枝子、铁杆蒿,而群落通过自然恢复演替到该阶段需15~20年^[24],这揭示封育管理可促进该区植被恢复^[16] ...

2015

0.0

卢翔, 南志标. 放牧对草地植物群落多样性和草地病害的影响. 草业科学, 2015, 32(9): 1423-1431.

, Nan Z

Perspectives in effects of grazing on diversity of grassland plant community and forage diseases.

Pratacultural Science, 2015, 32(9): 1423-1431. (in Chinese)

Grazing is one of the important ways to rational utilize, foster and improve grassland. Both grazing and grassland plant community diversity influence the incidence and severity of forage diseases. Grazing will affect forage diseases with different grazing intensities, methods and livestock. The diversity of grassland plant community including species richness and host plant density also affect forage diseases by affecting the usage of environmental resources, as well as the spread of pathogenic fungi. Meanwhile, the grazing intensities, livestock behavior, the types of rangeland, the history of grazing and grazing distribution patterns also increase or decrease the diversity of grassland plant communities. The present paper reviewed the effects of grazing on both grass plant community diversity and forage diseases and put forward the suggestions including combination of the research about the effects of grazing on diversity of grassland plant community and forage diseases in future; more deep study on genetic diversity and improvement of grazing management to reduce or control forage diseases. Thus, the goals of unifying grazing, disease management and sustainable use of grassland resources will be achieved.

Key Laboratory of Grassland Argo-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730020, China

放牧是合理利用、培育改良草地的重要方式之一。通过不同放牧强度、放牧方式以及家畜采食等提高或降低草地植物病害的发病率和病情指数。草地植被群落多样性包括物种丰富度和寄主植物密度，通过影响寄主植物对周围环境资源的利用以及病原真菌的传播来提高或降低病害的发病率和严重度。同时，不同放牧强度、家畜采食习性、草地生产类型、放牧史以及放牧分布型也分别提高或降低草地植物群落多样性。本文综述放牧对草地植物群落多样性和草地病害的影响，指出在以后的研究工作中把放牧对草地植物群落多样性的影响与草地植物病害的影响结合起来，并在遗传多样性方面加以研究，最终切实可行地通过提升放牧管理达到减轻或防止草地病害发生的目的，实现统一放牧、病害管理以及草地资源可持续利用的目标。

... 放牧是陆地生态系统最重要的管理方式之一,也是合理利用草地与培育改良草地必然涉及的重要问题^[25],它对植物群落的作用具有两面性,植物群落随着放牧强度的变化而受到不同程度的影响^[26] ...

2014

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李文怀, 郑淑霞, 白永飞. 放牧强度和地形对内蒙古典型草原物种多度分布的影响. 植物生态学报, 2014, 38(2): 178-187.

Li W

, Zheng S

, Bai Y

Effects of grazing intensity and topography on species abundance distribution in a typical steppe of Inner Mongolia.

Chinese Journal of Plant Ecology, 2014, 38(2): 178-187. (in Chinese)

Aims Our objective is to determine: 1) how species richness and abundance vary with grazing intensity and topography (i.e., flat vs. slope) in typical steppe of Inner Mongolia grassland, and 2) how common and rare species respond to grazing intensity and what role they play in species diversity maintenance. Methods The study was carried out at the Sino-German grazing experiment site, which was established in June 2004, and located in the typical steppe region of Inner Mongolia grassland dominated by Leymus chinensis and Stipa grandis . The experimental treatments included seven levels of stocking rates (i.e., 0, 1.5, 3.0, 4.5, 6.0, 7.5, 9.0 sheep·hm –2 ) and two topographical systems (i.e., flat and slope). Three hundred quadrats (1 m × 1 m each) were investigated on each plot in August 2009, and the total number of species and the number of individuals for each species were measured within each quadrat. The log-normal model, log-series model, and power fraction model were used to fit the observational data. Important findings Our results showed that the species richness and abundance increased at low stocking rates (1.5, 3.0 sheep·hm –2 ), but decreased at high stocking rates (7.5, 9.0 sheep·hm –2 ) on the flat, which partially supported the grazing optimization hypothesis. The power fraction model well fitted for entire species abundance at most of stocking rates, while the log-normal model only fitted well for entire species abundance just at the high stocking rates. The species richness and abundance decreased greatly with stocking rates on slopes. Abundance distribution of entire species at each of the stocking rates followed the log-normal function and power fraction function. The groups of common species and the entire species had similar responses in abundance to grazing at each of the stocking rates on both the flat and the slope, which were well fitted by both the power fraction model and log-normal model; whereas the groups of rare species and the entire species had similar richness responses to grazing at each of the stocking rates under both topographical features, which were well fitted by the power fraction model. It is suggested that the effect of grazing on species abundance in plant community depends on common species; whilst grazing effect on species richness depends on rare species. Our findings indicate that the niche partitioning mechanism plays an important role in species abundance maintenance in grassland ecosystems. To restore and maintain a high level of biodiversity and primary productivity in the Inner Mongolia grassland, it is necessary to reduce the excessively high stocking rate at present to a moderate level in future.

1 State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; 2 College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China; 3 State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Water and Soil Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling, Shaanxi 712100, China

为了更好地理解放牧对草原生态系统物种多度分布格局的影响, 以及常见种和稀有种对维持群落多样性的作用, 以内蒙古典型草原为研究对象, 基于长期放牧控制实验平台(包括7个载畜率水平(0、1.5、3.0、4.5、6.0、7.5、9.0 sheep·hm –2 )和两种地形系统(平地和坡地)), 研究了群落内全部物种、常见种和稀有种的丰富度和多度对放牧强度的响应规律, 并选取对数正态模型、对数级数模型和幂分割模型, 对物种多度数据进行拟合。结果表明: 1)平地系统中, 物种丰富度和多度在低放牧强度下(1.5、3.0 sheep·hm –2 )增加, 而在中、高度放牧强度下(4.5–9.0 sheep·hm –2 )降低, 全部物种的多度分布在大多数放牧强度下符合幂分割模型, 在高放牧强度下也符合对数正态模型; 坡地系统中, 物种丰富度和多度随着放牧强度增加而显著降低, 全部物种的多度分布在各个放牧强度下, 均符合幂分割模型和对数正态模型。2)随着放牧强度增加, 常见种的多度响应趋势与全部物种的响应趋势一致, 其多度分布均符合幂分割模型和对数正态模型; 稀有种的丰富度响应趋势与全部物种的响应趋势一致, 其多度分布符合幂分割模型, 同时也部分符合对数正态和对数级数模型。总之, 适宜的载畜率有利于生物多样性和初级生产力的提高, 平地系统中物种多度的响应在一定程度上支持放牧优化假说; 而坡地系统中不同物种多度的响应差异说明: 确定最佳载畜率时, 还需要考虑地形因素的影响。此外, 模型的拟合结果表明: 生态位分化机制对内蒙古典型草原物种多度分布起着主要作用, 常见种和稀有种通过不同的响应方式共同维持着草原生态系统的物种多样性。

2011

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1997

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王仁忠. 放牧影响下羊草草地主要植物种群生态位宽度与生态位重叠的研究. 植物生态学报, 1997, 21(4): 304-311.

Wang R

The niche breadths and niche overlaps of main plant populations in Leymus chinensis grassland for grazing.

Acta Phytoecologica Sinica, 1997, 21(4): 304-311. (in Chinese)

The niche breadths and niche overlaps of 12 main plant populations grown on the gradients of soil water, soil salt and soil organic content in Leymus chinensis grassland for grazing were measured using the formulas described by Shannon-Wiener and Pianka. The results show the niche breadths of Leymus chinensis, which were greater than other species, were 0.910, 0.869 and 0. 930 on the gradients of soil water, soil salt and soil organic respectively. The niche breadths of Lathyrus quinquenervius, Heleochalis intevsita and Phragmites communities were much narrower. Chloris virgata, which is one of the pioneer plant of grazing succession, had much greater niche breadths (average on the three gradients 0.707) than the other two species (Suaeda corniculata, Puccinellia tenuiflora ). The niche overlaps between the species with broad niche breadth and other species were much greater. The niche overlaps among the species distributed in the same/adjacent grazing stages or the species which have the same/similar environment requirements were great. Under grazing condition, the process of community succession was the one of species’ niche separate.

本文采用Shannon—Wiener和Pianka公式，在土壤水分、土壤含盐量和土壤有机质含量三维生态因子梯度上测定了松嫩草原碱化羊草草地放牧演替系列12种主要植物种群的生态位宽度和生态位重叠。结果表明，植物种群长期适应由放牧引起的群落和土壤环境因子梯度变化是种群生态位分化的主要原因。优势种羊草种群生态位宽度最大，三维上生态位宽度分别为0.910、0.869和0.930。五脉山黧豆和湿生植物生态位宽度均很窄。增加种表现出较强的适应环境能力，生态位宽度都较大。在放牧演替的先锋植物中，只有虎尾草生态位宽度较大(三维上平均0.707)，角碱蓬和星星草种群生态位宽度均很窄。生态位宽度较大的物种与其它种群间生态位重叠较大。分布于相同或相邻放牧阶段及具有相同或相似环境要求的物种间生态位重叠较大。放牧条件下，羊草群落的演替过程也就是种群生态位分化的过程。

2014

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连仲民, 徐文轩, 杨维康, David

Blank

, 黄怡. 放牧对草地土壤种子库的影响. 草业科学, 2014, 31(12): 2301-2307.

Lian Z

, Xu W

, Yang W

, Blank

, Huang

Effects of livestock grazing on soil seed bank: A review.

Pratacultural Science, 2014, 31(12): 2301-2307. (in Chinese)

Grazing is an important way for grassland utilization. Livestock has direct and indirect impacts on soil seed bank through feeding, excretion and trampling during the grazing process which change the relationship between soil seed bank and plant community. In the present paper, we summarized the effects of grazing on size, species composition, spatial distribution pattern of soil seed bank and its relationship with plant community to provide a theoretical basis for sustainable utilization and management of grassland, and promote the further researches of grazing impacts on grassland.

1.Key Laboratory of Biogeography and Bioresources in Arid Land, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China; 2.University of Chinese Academy of Sciences, Beijing 100049, China; 3.Department of Foundational Sciences, Xinjiang Petrolic College, Urumqi 830000, China

放牧是草地利用的主要方式。在放牧过程中, 牲畜通过采食、排泄和践踏等方式直接或间接地影响草地土壤种子库, 土壤种子库和植物群落间的关系也因此会发生变化。本文主要从放牧对土壤种子库规模、物种组成、空间分布格局及土壤种子库和植物群落间的互作关系4个方面做了归纳总结, 旨在为草地生态系统的可持续利用和管理提供理论依据。

... 其次,家畜在草地的活动协助某些植物传播种子,促使这些植物水平分布更广,越有利于种子迅速找到适宜的生存环境^[29],从而使其生态位拓宽,如本研究中的长芒草 ...

2008

0.0

... 施肥管理下,土壤中的养分资源增加,群落盖度明显高于其它管理方式(表1),一些喜肥物种^[30](阿尔泰狗娃花和达乌里胡枝子)具备更高的生长率,促进地上生物量和盖度的增加,导致生态位宽度的增加 ...

2009

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... 达乌里胡枝子因具备固氮能力而生长迅速^[31],生态位宽度随之拓宽 ...

2010

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... 优势种的快速生长使群落郁闭度增大,光源获取能力和光竞争能力增强,导致群落下层不耐阴物种或个体较小物种减少或死亡^[32] ...

2015

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井光花, 程积民, 苏纪帅, 魏琳, 史晓晓, 金晶炜. 黄土区长期封育草地优势物种生态位宽度与生态位重叠对不同干扰的响应特征. 草业学报, 2015, 24(9): 43-52.

Jing G

, Cheng J

, Su J

, Wei

, Shi X

, Jin J

Response of dominant population niche breadths and niche overlaps to various disturbance factors in typical steppe fenced grassland of China’s Loess Plateau region.

Acta Pratacultural Science, 2015, 24(9): 43-52. (in Chinese)

The Levins niche breadth and Pianka niche overlap indices were used to assess the response of plant population niches to grazing, burning and fertilization in permanently fenced grassland of the Loess Plateau region. Species with highest niche width in fenced (control group), grazed, burned and fertilized grasslands were Carex rigesaens , Ixeridium chinense , Artemisia sacrorum , and Stipa bungeana , respectively. The niche breadth of S. bungeana in different disturbance situations (ranked highest to lowest) was: fertilization (1.362)>burning (1.244)>fencing (1.088)>grazing (1.026). The richness index for the same four treatments ranked: grazing>fertilization>burning>fencing. The average values of niche overlap of all the species and dominant species ranked: fertilization>fencing>burning>grazing. The pairs of species with the highest niche overlap in fertilized, fenced, burned, and grazed grasslands were, respectively, S. bungeana and C. rigesaens , Stipa grandis and C. rigesaens , S. grandis and C. rigesaens , and I. chinense and Poa sphondylodes , respectively. These findings indicate that human disturbance can increase the species richness and improve plant population niche width to facilitate maximum resource use in permanently fenced grassland.

1.Institute of Soil and Water Conservation, Chinese Academy of Sciences & Ministry of Water Resources, Yangling 712100, China; 2.Graduate University of Chinese Academy of Sciences, Beijing 100049, China; 3.Northwest Agricultural & Forestry University, Yangling 712100, China

运用Levins生态位宽度指数和Pianka生态位重叠指数及物种丰富度,初步分析了长期封育草地优势种群生态位对放牧、火烧和施肥的响应特征。结果表明:在封育(对照组)、放牧、火烧和施肥干扰下,生态位宽度最大的物种依次是白颖苔草、中华小苦荬、白莲蒿和本氏针茅;建群种本氏针茅在不同干扰下生态位宽度表现为施肥(1.362)>火烧(1.244)>封育(1.088)>放牧(1.026),物种丰富度指数则依次为放牧>施肥>火烧>封育。所有物种和优势种的生态位重叠指数平均值均表现为施肥>封育>火烧>放牧,且在各干扰下,生态位重叠指数最大的种对依次为本氏针茅和白颖苔草、大针茅和白颖苔草、大针茅和白颖苔草以及中华小苦荬和硬质早熟禾。综上所述,对长期封育的草地进行适度的干扰可提高物种丰富度,改善种群的生态位配置和最大限度地利用环境资源。

... 同时,资源的增加改变了群落内物种的相对竞争能力,使优势种(阿尔泰狗娃花)地下、地上竞争能力增强^[33] ...

2012

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王辉, 谢永生, 程积民, 摄晓燕. 基于生态位理论的典型草原铁杆蒿种群化感作用. 应用生态学报, 2012, 23(3): 673-678.

Wang

, Xie Y

, Cheng J

, She X

Allelopathic effects of Artemisia sacrorum population in typical steppe based on niche theory.

Chinese Journal of Applied Ecology, 2012, 23(3): 673-678. (in Chinese)

By using modified Levins niche width index and Pianka niche overlap index, this paper analyzed the ecological competition between constructive and dominant species in a typical steppe. The stem- and leaf extracts from the constructive species (Artemisia sacrorum) were utilized to study their allelopathic potential on the seed germination and plant growth of the dominant species (Stipa bungeana, Thymus mongolicus, S. grandis, and Leymus secalinus), and the ecological position of A. sacrorum in the steppe succession. In the steppe, S. bungeana had the widest niche width (099), followed by T. mongolicus (0.94), A. sacrorum (0.82), S. grandis (0.76), and L. secalinus (073). The niche overlap value between A. sacrorum and S. bungeana, S. bungeana and T. mongolicus, T. mongolicus and S. grandis, and A. sacrorum and T. mongolicus was 0.90, 0.95, 0.94, and 0.86, respectively. The allelopathic effects of A. sacrorum extracts varied with their concentration. For the seed germination, root growth, and shoot growth of the dominant species, A. sacrorum extracts showed a trend of promoting at low concentrations and inhibiting at high concentrations. The extracts of A. sacrorum had a stronger promotion effect on the root growth of S. bungeana than on that of T. mongolicus, but a stronger inhibition effect on the shoot growth of T. mongolicus than on that of S. bungeana. Methanol extracts had stronger allelopathic effects than aqueous extracts. The high niche overlap between A. sacrorum and S. bungeana, and T. mongolicus and S. grandis indicated that the steppe community would continue succession to S. bungeana, while A. sacrorum population was only an important transitional stage during the succession. The allelopathic effect of A. sacrorum played a driving role in the succession process.

1College of Resources and Environment, Northwest A & F University, Yangling 712100, Shaanxi, China; 2Institute of Soil and Water Conservation, Chinese Academy of Sciences & Ministry of Water Resources, Yangling 712100, Shaanxi, China; 3Institute of Soil and Water Conservation, Northwest A & F University, Yangling 712100, Shaanxi China

运用改进的Levins 生态位宽度指数和Pianka 生态位重叠指数，研究了典型草原草地建群种与优势种之间的生态竞争关系；并利用建群种（铁杆蒿）茎叶浸提液对不同优势种的化感种子进行发芽试验，分析铁杆蒿的化感潜力及其在封育草地中的生态地位.结果表明：封育草地中，本氏针茅的生态位最宽（0.99），其次为百里香(0.94)、铁杆蒿(0.82)和大针茅(076)，赖草最窄（0.73）；铁杆蒿与本氏针茅、本氏针茅与百里香、百里香与大针茅、铁杆蒿与百里香之间的生态位重叠值分别为0.90、0.95、0.94和0.86.不同浓度的铁杆蒿浸提液对植物的化感作用强度不同，表现为“低促高抑”.铁杆蒿浸提液对本氏针茅幼苗根系生长的化感促进作用要强于百里香，而对百里香幼苗芽生长的抑制作用要强于本氏针茅.甲醇浸提液的化感作用要强于水浸提液.铁杆蒿、本氏针茅、百里香和大针茅之间高的生态位重叠，说明该草地群落将继续向本氏针茅群落演替，铁杆蒿群落仅是一个重要的过渡演替阶段.铁杆蒿的化感作用在其中担负着驱动力的角色.

... 铁杆蒿生命力极强,根蘖性强,能迅速分蘖出枝条,且具有化感作用^[34],抑制其它物种的生长,使其它物种生态位宽度降低 ...

... 灭鼠管理的群落,由于人为去除食物链上端的动物,优势物种缺乏天敌的抑制而继续扩大优势地位,外加铁杆蒿的化感作用^[34],使猪毛蒿、大针茅和铁杆蒿的生态位宽度值明显高于其它物种 ...

2014

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杨中领, 苏芳龙, 苗原, 钟明星, 肖蕊. 施肥和放牧对青藏高原高寒草甸物种丰富度的影响. 植物生态学报, 2014, 38(10): 1074-1081.

Yang Z

, Su F

, Miao

, Zhong M

, Xiao

Effects of fertilization and grazing on species richness in an alpine meadow of Qinghai-Xizang Plateau.

Chinese Journal of Plant Ecology, 2014, 38(10): 1074-1081. (in Chinese)

Aims Plant species diversity often declines when nutrients are added in grassland. However, the mechanisms for explaining biodiversity loss due to nutrient enrichment have remained controversial. Our objective was to explore the potential mechanisms of diversity decline. Methods In this paper, based on a four-year experiment of nutrient addition and grazing in an alpine plant community, we investigate the potential mechanisms of diversity loss by comparing the above- and below-ground competitions using coefficient of variation and nitrogen use efficiency under fertilization scenario both in grazed and non-grazed plots. Important findings Fertilization increased the size inequality of individuals by 15%, increased species height by different degrees, and reduced the number of species pairs that differed significantly in nitrogen content by 65% in the non-grazed plots. The results indicate that the large-sized individuals out-competed the small-sized individuals due to competition for light, which led to a decline in species richness by 29.6% in the non-grazed plots following fertilization. In contrast, fertilization did not change the size inequality of individuals and species height in the grazed plots, and increased the number of species pairs that differed significantly in nitrogen content by 11.4%, implying that an increased competition for soil nitrogen among species reduced the species richness by 17.3%. Our study also suggests that grazing delayed the effect of fertilization on species richness as inferred by the lower rate of species loss in the grazed plots.

1 School of Life Science, Henan University, Kaifeng, Henan 475000, China; 2 College of Resources and Environmental Science, Nanjing Agricultural University, Nanjing 210000, China

在草地生态系统中, 施肥通常会导致生物多样性下降, 但是关于引起生物多样性下降的机制还存在着很大的争议。该研究基于一个4年的施肥实验, 试图通过个体大小的不整齐性和单位植物氮含量, 定性地揭示青藏高原东部高寒草甸施肥后多样性下降的原因。研究显示: 在封育地, 施肥致使个体大小不整齐性增加了15%, 并不同程度地增加了物种的高度。同时, 施肥使物种间单位植物氮含量存在显著差异的数目降低了65%。施肥后光竞争加剧, 导致大个体植物排斥小个体植物, 进而引起了物种丰富度下降29.6%。与封育地不同, 放牧地施肥并没有改变个体大小不整齐性和物种的高度, 而是使物种间单位植物氮含量存在显著差异的数目增加了11.4%。施肥并没有改变放牧地的光竞争强度, 而是增加了物种间对土壤营养元素氮的竞争强度, 进而引起了物种丰富度下降17.3%。该研究还发现, 放牧施肥地的物种丰富度下降速度和等级显著低于封育施肥地的物种丰富度下降速度和等级, 这表明放牧减缓了施肥对物种丰富度的影响力。

... 也有研究证实了长期施肥使地下养分竞争的强度减弱,光竞争增强,使群落结构简单^[35] ...

2005

0.0

章家恩, 刘文高, 陈景青, 施耀才, 蔡燕飞. 不同刈割强度对牧草地上部和地下部生长性状的影响. 应用生态学报, 2005, 16(9): 1740-1744.

Zhang J

, Liu W

, Chen J

, Shi Y

, Cai Y

Effects of different cutting intensities on above-and underground growth of Stylosanthes guianensis.

Chinese Journal of Applied Ecology, 2005, 16(9): 1740-1744. (in Chinese)

Based on the 2002 field experimental results in the Wusi Farm of Fengxian County in Shanghai and related studies,and by the methods of ecological economy and environmental economy,this article examined and estimated the nitrogen input and output,and the economic values of nitrogen transformation in rice field ecosystems.The results indicated that the plot without N fertilization showed a deficit of nitrogen budget,while those with urea application showed a surplus.The economic value of the plot without urea amendment was evaluated to be positive,while that of the plots with urea application was calculated to be negative.The negative value of the plots with urea amendment resulted from the nitrogen losses through ammonia volatilization,nitrogen leaching and runoff,which had serious harmful impacts on environment and human society.Therefore,only when some measures were taken to encourage and facilitate farmers to improve the efficiency of urea application and to mitigate the environment problems from N losses in the process of food production,the advantages of nitrogen transformation in rice fields could be promoted,and the sustainability of agriculture would become reality.

1. Institute of Geographical Science and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; 2. Graduate School of Chinese Academy of Sciences, Beijing 100039, China

根据2002年上海奉贤县五四农场田间实验数据,结合相关研究结果对稻田氮素输入和输出进行研究,并运用生态经济学和环境经济学方法计算稻田生态系统氮素转化的经济价值.结果表明,当季不施氮肥的处理小区氮素收支出现赤字;而施加氮肥的处理小区氮素收支都出现盈余.不施氮处理小区单位面积稻田提供的氮素转化综合价值为正;而施加氮肥的小区其氮素转化的综合价值都为负.施氮处理小区氮素转化的负价值主要是由于过量氮肥导致田间氮素以氨挥发、渗漏和径流方式损失造成.

... 由于刈割阻止了养分的回归^[36],使刈割管理的群落中具有固氮能力且抗旱能力较强的达乌里胡枝子和紫花苜蓿成为优势物种 ...

2000

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... 此外,刈割导致群落盖度下降,蒸发增大^[37],所以耐旱植物生态位宽度整体高于喜阴植物 ...

... 刈割和灭鼠影响草地生态系统的能量流动和物质循环^[37],优势种生态位宽度和生态位重叠变小,使个别物种处于优势地位,降低草地物种多样性,对草地健康会产生严重干扰 ...

2008

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许中旗, 李文华, 许晴, 闵庆文, 王英舜, 何旭生. 禁牧对锡林郭勒典型草原物种多样性的影响. 生态学杂志, 2008, 27(8): 1307-1312.

Xu Z

, Li W

, Xu

, Min Q

, Wang Y

, He X

Effects of grazing prohibition on species biodiversity of typical steppe in Xilinguole.

Chinese Journal of Ecology, 2008, 27(8): 1307-1312. (in Chinese)

In order to understand the effects of grazingprohibition on the spec ies diversity of typical steppe, the species composition of typical steppe in Xi linguole of Inner Mongolia was investigated under the conditions of free grazing and of grazingprohibition since 1987, 1997, and 2003. The results showed that grazingprohibition did not change the composition of dominant species markedly, but affected the relative importance of the species, with the dominance of dominant species increased. At the same time, grazingprohibition enhanced the species diversity of the typical steppe in a definite period of time, but, as the period of grazingprohibition extended, the species diversity and the richness of the typical steppe decreased. Moreover, under the same conditions of grazing or grazingprohibition, the steppe with better water condition had higher species diversity. It was concluded that an appropriate duration of grazingprohibition and favorable water condition was in favor of the maintenance of the species diversity of typical steppe, and the decline in species diversity of typical steppe in the region could be ascribed to the overgrazing and droughty environment condition.

1 Agricultural University of Hebei, Baoding 071000, Hebei, China;  2 Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; 3 Institute of Animal Husbandry and Meteorology of Xilinguole, Xilinhot 026000, Inner Mongolia, China

为了研究禁牧对典型草原物种多样性的影响，对自由放牧和不同时间（1987、1997 和2003年）禁牧的典型草原的物种组成进行了调查。结果表明：禁牧并未使典型草原的主要物种组成发生明显的改变，但使物种的相对重要性发生了明显变化，优势种的优势更加明显；同时，禁牧在一定的时间内可以提高典型草原的物种多样性，但随着禁牧时间的延长，典型草原的物种多样性和丰富度都表现出一种先上升后下降的趋势；在相同的禁牧或放牧条件下，水分条件较好的典型草原具有更高的物种多样性。可见，合理的禁牧时间与优越的水分条件有利于典型草原维持较高的物种多样性。典型草原物种多样性下降可能是人为干扰与干旱环境条件共同作用的结果。

1995

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... 2 不同管理方式草地群落生态位重叠分析生态位宽度较大的物种之间的生态位重叠机会较大^[39,40],本研究也得到相似结果 ...

2002

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张林静, 岳明, 张远东, 顾峰雪, 潘晓玲, 赵桂仿. 新疆阜康绿洲荒漠过渡带主要植物种的生态位分析. 生态学报, 2002, 22(6): 969-972.

Zhang L

, Yue

, Zhang Y

, Gu F

, Pan X

, Zhao G

Analysis on the niche of the main plant species of Oasis-deseart E-cotone in Fukang of Xinjiang.

Acta Ecologica Sinica, 2002, 22(6): 969-972. (in Chinese)

The niche differentiation of 7 main species in oasis-desert ecotone in Fukang of Xinjiang was analyzed quantitatively with respect to community gradients and single ecological factor gradients, i.e. soil moisture, soil salinity and soil acidity, by Levins formula and the method by Wang gang. The results were as follows: (1) according to community gradients, the order of niche breadth was Reaumuria soongorica(0.7010), Haloxylon ammodendron(0.6434), Ceratocarpus arenarius(0.4774), Bassia dasyphylla(0.3745), ...

采用 Levins公式和王刚生态位重叠计测方法 ,对新疆阜康绿洲荒漠过渡带中的 7个植物种 ,分别从群落梯度和 3个单一生态因子 (土壤水分维 ,土壤盐分维 ,土壤酸碱度维 )上对其生态位分化进行了定量分析。结果如下 :1在群落梯度上 ,生态位大小依次为红砂 ( 0 .70 1 0 ) ,梭梭 ( 0 .6 4 34 ) ,角果藜 ( 0 .4 774 ) ,雾冰藜 ( 0 .374 5 ) ,盐爪爪 ( 0 .35 4 1 ) ,叉毛蓬( 0 .335 4 )和碱蓬 ( 0 .2 76 9) ;2红砂在土壤水分、土壤盐分、土壤酸碱度维上的生态位分别为 0 .5 2 74 ,0 .6 0 39和 0 .36 2 0 ,梭梭在这 3维上分别为 0 .332 0 ,0 .30 83和 0 .5 1 0 3,从生态位宽度看 ,红砂和梭梭处于优势种地位 ,其余为非优势种 ;3每个物种在群落梯度上的生态位宽度基本大于在上述 3个资源轴上的平均生态位 ;4红砂与梭梭在土壤盐分维上的生态位重叠最大 ( 0 .4 2 0 3) ,表明了这两个优势种在利用土壤盐分方面有相似的特性。

... 2 不同管理方式草地群落生态位重叠分析生态位宽度较大的物种之间的生态位重叠机会较大^[39,40],本研究也得到相似结果 ...

2006

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李瑞, 张克斌, 张生英, 杨晓晖, 乔峰. 宁夏盐池人工封育草原植物生态位研究. 中国水土保持科学, 2006, 4(1): 49-54.

, Zhang K

, Zhang S

, Yang X

, Qiao

Vegetable niche of enclosed grassland in Yanchi County of Ningxia.

Science of Soil and Water Conservation, 2006, 4(1): 49-54. (in Chinese)

In order to find the vegetable niche pattern in arid and semi-arid grassland region,the niche breadth and niche overlapping in Yanchi county of Nixia in 2002 and 2003 are measured by means of Levins niche breadth and Pianka niche overlapping indexes of enclosed grassland.The results showed that,the biological and ecological characteristics of Artemisia capillaris Thunb determined its predominant station in this(region),and its niche breadth in 2002 and 2003 were bigger than other species(0.758 and 0.868) continuing to keep rising trend.The results of niche overlapping in 2002 and 2003 also showed that the species with big niche breadth didn't always have big niche overlapping,and the niche breadth and niche overlapping did not have a positive direct linear relation.The higher Pianka niche overlapping in 2002 and 2003 both appeared in the species with low niche breadth,which showed from another point of view that environment and resources have high spatial heterogeneity during the vegetation restoration process.

1.College of Soil and Water Conservation,Beijing Forestry University,100083, Beijing;2.Yanchi Mechanical Forestry Centre in Ningxia,751500,Yanchi,Ningxia;3.Institute of Forest Sciences,Chinese Academy of Forestry,100091,Beijing: China

为了解干旱半干旱区草原植物生态位格局,运用Levins生态宽度指数及Pianka生态位重叠指数,对宁夏盐池人工封育草原2002年及2003年植物生态位宽度及生态位重叠进行计量。结果表明:茵陈蒿的生物、生态学特性决定了它在该区的优势地位,2002年、2003年其生态位宽度远远高于其他物种(0.758和0.868),并且继续保持上升趋势;2002年及2003的生态位重叠结果均表明,生态位宽度大的物种不一定和其他物种有大的重叠值,较高的生态位宽度和较高的生态位重叠之间并不存在直接的线性关系;2002年、2003年较高的Pianka生态位重叠值都出现在生态位宽度较小的物种之间。这一现象从另外一个角度说明植被恢复过程中环境资源存在着高度的空间异质性。

2008

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陈艳瑞, 尹林克. 人工防风固沙林演替中群落组成和优势种群生态位变化特征. 植物生态学报, 2008, 32(5): 1126-1133.

Chen Y

, Yin L

Community composition and niche change characteristics of dominant species in the wind-breaking and sand -fixing forest, Xinjiang, China.

Journal of Plant Ecology, 2008, 32(5): 1126-1133. (in Chinese)

Aims Our purpose is to examine changes in community composition and niche characteristics of dominant species in an artificial plant community in the wind-breaking and sand-fixing forest in the lower reaches of the Tarim River, Xinjiang, China. Findings will provide a case for sustainable management of artificial plant communities in desert inland river basins. Methods Using representative plots, we sampled 24 locations for species diversity, community structure and interspecific relationships from August 2004 to June 2007. Dominant species were identified based on species’ Importance Index in the communities. Niche breadth and overlap were calculated and analyzed using Simpson’s and Pianka’s methods. Important findings Community composition between planted and existing communities changed in the seven years. Species diversity increased over four years and then decreased, and community structure became more complex. After four years, the invasion of native species changed the artificial community into an artificial-natural plant community, with changes in dominant species. Niche breadths of dominant species were Phragmites communis > Karelinia caspica > Calligonum caput - medusae > Elaeagnus angustifolia > P. euphratica > Tamarix ramosissima > Haloxylon ammodendron > H. glomeratus . The niche overlap value between C. caput - medusae and P. euphratica was the largest among dominant species. At the present stage of community succession, there is no relationship between niche breadth and niche overlap of dominant species, which shows that there is competition among plants and high spatial heterogeneity of environmental resources.

1Key Laboratory of Oasis Ecology and Desert Environment, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China;2Turpan Eremophytes Botanic Garden, Chinese Academy of Sciences, Turpan, 838008, China;3Graduate University of Chinese Academy of Sciences, Beijing 100049, China

以塔里木河下游绿洲外围大型防风固沙林为研究对象, 采用基于Simpson多样性指数的生态位宽度公式和Pianka生态位重叠测度公式, 在群落梯度上按重要值大小筛选出优势种群进行生态位分析, 探讨这些群落在4~7年的发育过程中生态位变化特点。结果表明: 1)经过4年的发育, 植物种组成简单的人工防风固沙林由于乡土植物种的侵入, 演变成为人工-天然植物群落, 不同地段群落中的优势种群发生了较大的变化, 优势种群共7个。芦苇( Phragmites communis )、花花柴( Karelinia caspica )和盐生草( Halogeton glomer atus)这3个乡土植物种侵入后逐渐成为优势种群, 而原人工群落主要建群种宁夏枸杞( Lycium barbarum )种群逐渐消退; 7年后, 优势种群共6个。由于水分条件的变化, 多枝柽柳( Tamarix ramosissima )成为优势种群, 而芦苇降为亚优势种群, 盐生草种群发生消退; 2)人工-天然植物群落中优势种群以耐旱耐盐碱植物占主要优势向占绝对优势的方向发展, 其生态位宽度变化幅度为0.56~0.86, 生态位宽度排序为芦苇>花花柴>头状沙拐枣( Calligonum caput-medusae )>沙枣( Elaeagnus angustifolia )>胡杨( Populus euphratica )>多枝柽柳>梭梭( Haloxylon ammodendron )>盐生草; 3)生态位重叠最大值发生在头状沙拐枣和胡杨种群之间; 4)在乡土植物种向人工群落侵入的过程中, 生态位宽度较大(或较小)的种群, 它们所构成的种对间生态位重叠既有较大的, 也有较小的, 可见生态位宽度与生态位重叠程度无相关性; 表明在现阶段群落演变中, 植物对环境资源存在着激烈的竞争和高的空间异质性。

2008

0.0

... 不同管理方式下各优势种对生态位重叠差异明显,由于管理方式不同造成群落组成的不确定性,以及植物对环境资源存在着激烈的竞争和高的空间异质性^[43] ...

2015

0.0

斯贵才, 袁艳丽, 王建, 王光鹏, 雷天柱, 张更新. 围封对当雄县高寒草原土壤微生物和酶活性的影响. 草业科学, 2015, 32(1): 1-10.

Si G

, Yuan Y

, Wang

, Wang G

, Lei T

, Zhang G

Effects of fencing on microbial communities and soil enzyme activities in Damxung alpine grassland .

Pratacultural Science, 2015, 32(1): 1-10. (in Chinese)

The deterioration of soil ecosystem and soil degradation related to overgrazing were serious and cannot be restored in short period. In order to determine the impacts of fencing on the soil enzyme activities and soil microbial communities in Damxung steppe, the activities of β-glucosidase, invertase, phenol oxidase, peroxidase, L-asparaginase, protease, urease and alkaline phosphatase were investigated, as well as the biomass of bacteria, fungi, actinomycete, gram-positive bacteria and gram-negative bacteria. Water soluble organic carbon (WSOC) and water soluble organic nitrogen (WSON) in soils with all fencing treatments were significantly higher ( P ＜0.05) than that in grazing soils. There were significant variations of soil moisture and pH between grazing and fencing 6 years. Invertase and L-asparaginase activities significantly increased with the fencing year extended. The biomass of bacteria, actinomycete and gram-positive bacteria in soil with 6 years fencing were significantly higher ( P ＜0.05) than that in soil. All of these results suggested that fencing changed not only soil physicochemical properties, but also soil enzyme activities and microbial communities. The further pearson correlation analysis showed that WSOC, WSON and moisture had significantly positive correlation with soil enzyme activities and soil microbial communities which suggested that all of tested factors could be good indicators for grassland degradation and restoration. All of these results showed that fencing helped improving soil organic matter to promote growth of microorganism and recovery of alpine grassland ecosystem.

1.Gansu Provincial Key Laboratory of Petroleum; Key Laboratory of Petroleum Resources Research, Institute of Geology and Geophysics, Chinese Academy of Sciences, Lanzhou 730000, China; 2.Laboratory of Alpine Ecology and Biodiversity, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China; 3.Graduate University of Chinese Academy of Sciences, Beijing 100049, China

过度放牧会严重破坏土壤生态系统,造成土壤退化,土壤一旦退化,即使很长年限也难以恢复。本研究通过围栏禁牧(1、4、6年)对青藏高原当雄县高寒草原退化草地进行修复,分析围封时间对高寒草原土壤理化性质、土壤微生物和酶活性的影响,以期阐明围封对高寒退化草地修复的影响。结果表明,与放牧土壤相比,围封1、4和6年的草地土壤水溶性有机碳和水溶性有机氮含量显著提高( P ＜0.05),围封6年的土壤含水量显著增加,pH值显著降低;围封显著改变了土壤蔗糖酶和L-天冬酰胺酶活性,土壤蔗糖酶和L-天冬酰胺酶活性均随着围封年限的延长有增加的趋势;围封6年土壤细菌、放线菌和革兰氏阳性细菌含量相比放牧显著升高。因此,围封不仅会引起土壤物理化学性质的变化,而且土壤酶活性与土壤微生物群落结构都会发生相应改变。Pearson相关性分析表明,水溶性有机碳、水溶性有机氮、土壤水均与土壤酶活性和微生物类群生物量显著或极显著( P ＜0.01)相关,因此这些指标可以指示退化草地修复状况。围栏禁牧有利于提高土壤易降解有机质含量,从而促进微生物生长,加速营养物质循环,促进高寒草原生态系统的恢复。

... 同时,围栏封育和轻度放牧可以提高土壤中各类群微生物的生物量,从而调节和改善土壤营养状况,促进植物生长^[44] ...