Protection status as determinant of carbon stock drivers in Cerrado sensu stricto

天然植被在全球碳循环和碳储存中扮演着重要角色。巴西大草原塞拉多保护区(Cerrado)因自身固有特性被认为是一个碳汇。本研究的目的是评估具有不同保护状况的三个地区,控制区(法定保护区)、保护区(PA)和非保护区(Non-PA)地上生物量与生物多样性关系的变化。这三个被研究的地区都位于巴西米纳斯吉拉斯州(Minas Gerais)北部。根据森林清查资料,该研究对地上碳储量进行了估算,并测量了每个地区生物多样性指标的三个维度：功能性状优势度、分类学多样性和功能多样性。对物种的以下功能性状进行了评价：木材密度、最大直径和种子大小。通过建立广义线性模型,评估了碳储量、群落加权平均值、物种丰富度和多样性以及功能多样性指数在不同地区间的差异。 研究结果表明,未受保护的地区碳储量、物种丰富度、物种多样性、功能丰富度和功能分散度均较低,而保护区和非保护区群落加权平均值最大直径和种子大小均低于法定保护区。广义线性模型结果表明,碳储量与物种和功能丰富度指数在同一地区内和不同地区间存在相关性,因此,物种丰富度可以作为功能丰富度和碳储量的替代指标。物种丰富度和群落加权平均值最大直径对碳储量有正向影响,功能分散度对碳储量有负向影响。功能丰富度、物种多样性和群落加权平均值种子大小出现在最佳模型中,但对碳储量没有显著的直接影响。因此,我们的结论是,在缺乏保护的巴西塞拉多地区会降低物种丰富度和碳储量。     

江西武夷山河岸带阔叶林群落的物种组成和多样性分析

以江西武夷山国家级自然保护区河岸带阔叶林群落为研究对象,对其物种组成进行调查,并采用物种丰富度指数、多样性指数和均匀度指数分析物种多样性。结果表明,保护区河岸带物种极丰富,三条水系10个样方中共调查到维管束植物93科174属304种,群落建群种和灌木层优势种均以常绿阔叶树种为主,物种组成具有典型的亚热带植被特色,以壳斗科、樟科、山茶科物种最多。保护区不同海拔河岸带物种丰富度指数、多样性指数的变化规律基本一致。     

珍稀濒危植物金花茶的群落学特征

据1600m2样方调查,金花茶集中分布的群落中,胸径大于1cm的立木植物有119种,隶属40科80属。其中以热带分布的属占绝对优势,占总属数的92.5%,充分说明群落的热带性质。不同海拔高度的4个群落均为次生林类型,外貌常绿,结构相对较简单,乔木层可分2~3层,村边林群落高度可达16~20m,乔木分3层,保护区内群落高度10m左右,乔木分2层。群落优势种较明显,粗糠柴、降真香等在各群落均为优势种。群落单位面积内的种数和个体数目均较大,少见大径级立木,可见群落处于强烈的进展演替阶段。群落的物种多样性指数和生态优势度均较高,但群落具较低的均匀度,说明群落仍处于演替的中早期,且优势种较明显。     

海南鹦歌岭轮叶三棱栎(Trigonobalanus verticillata) 群落特征与保护对策

应用样方调查法,研究了中国分布新记录种--轮叶三棱栎（Trigonobalanus verticillata）种群结构及其所处森林群落特点。结果表明：轮叶三棱栎仅分布于海南鹦歌岭海拔1100-1400m近山脊处的热带山地雨林及热带山地常绿阔叶林群落中,与陆均松（Dacrydium pectinatum）、海南阿丁枫（Altingia obovata）等树种伴生。在2个面积为1500m^2的调查样方中共记录了90种乔灌木树种,均匀度和Shannon-Wiener指数分别为0.81、0.86和3.20、3.27,轮叶三棱栎的重要值在群落中排在第9-10位;种群结构分析结果显示该种群数量小且无Ⅰ龄级和Ⅲ龄级,属不稳定种群;轮叶三棱栎生态位宽度为1.69,在群落中仅排第19位,与陆均松和鸡毛松（Dacrycarpus imbricatus）的生态位重叠值分别为0.59和0.68,但与群落优势种的生态位重叠值多小于0.3。鹦歌岭在海拔1000m以上具有较大面积的台地和人为破坏较少可能是该种群得以幸存的重要因素,加强就地保护,开展该种植物的生物学特性研究,并建立国家级保护区,将海南中部山区各保护区有机地联合在一起为保护良策。     

竹叶眼子菜种群遗传多样性与群落物种多样性关系的研究

以洪湖中的沉水植物群落及其优势种竹叶眼子菜(Potamogeton wrightii Morong)为研究对象,利用AFLP分子标记结合野外调查的方法,分析保护区(干扰较小)与非保护区(干扰较大,敞水区)中沉水植物群落的物种多样性与竹叶眼子菜遗传多样性之间的相关性。结果显示:洪湖沉水植物群落物种丰富度(S)和物种多样性辛普森指数(D)在保护区和非保护区均未发现显著性差异;竹叶眼子菜的重要值(IV)在保护区(5.2%~23.2%)较非保护区(8.5%~73.3%)稳定。竹叶眼子菜的遗传多样性在两个区未发现显著差异,其遗传多样性与群落物种多样性这两个指标在保护区、非保护区及全湖水平均不相关,说明沉水植物群落的物种多样性和竹叶眼子菜的遗传多样性对不同环境干扰的响应有所差异。     

羊草草原种群分布格局的最适取样面积

只有提供足够的环境空间才能保证展现出特定群落类型的种类组成和结构特征的真实面貌,然而,反映群落种类组成的种-面积曲线所给出的最小面积远不能反映种群结构和群落结构的特征。本文将以统计学的方法对研究种群个体分布格局的最适取样面积作深入探讨。 应用Greig-Smith格局分析的原理,计算在一个由小到大的样方面积系列中测得种多度值均方的变化,得到了随样方面积逐级增大的多度值均方的变化曲线,变化曲线表明:8个植物种群的变化曲线韵峰值基本上都出现在区组16到32范围内,表示这些种群个体斑块的聚块群的平均面积在288—576平方米,所以,对多数种群来说,500平方米(12米×40米)的样方可以作为研究种群个体分布格局的最适取样面积。     

广东北部山区若干森林群落

应用植被样方调查法,对地处粤北山区的连州田心、乐昌八宝山、曲江罗坑、仁化范子山、始兴刘张家山、平远龙文-黄田等自然保护区的森林植被优势种进行比较分析,并用极点排序法对上述6地的森林群落进行二维排序。结果表明:各地共有优势种仅有红楠和枫香2种,且优势度差异明显。各地群落的相似性系数以田心与龙文-黄田之间的65.49%为最大;八宝山与其它各地的群落相似性程度均小于50%。群落相似性系数与极点排序结果均提示森林群落的相似性程度受土壤基质、海拔高度的影响要大于经纬度和地理距离的影响。各地森林群落间接地反映了它们的生境条件,对保护区森林群落的比较研究,可为今后广东自然保护区的网络建设提供参考。     

新疆卡山自然保护区典型水源地植物群落特征及其与土壤因子的关系

该研究通过样方调查法对卡拉麦里山有蹄类野生动物自然保护区(卡山自然保护区)水源地植物种类及数量进行统计,利用TWINSPAN和DCA进行植物群落数量分类和排序,并对保护区典型水源地土壤理化性质与植物群落物种多样性指数的相关关系进行CCA分析。结果表明:(1)卡山自然保护区32个典型水源地调查共记录到15科41属53种植物。(2)群落分类共分为7个群落,分别为:铃铛刺群落、沙拐枣-麻黄群落、白刺+柽柳-蛇麻黄+羽毛三芒草群落、芨芨草+白茎绢蒿群落、盐爪爪群落、白刺群落、柽柳+盐爪爪-芨芨草群落。(3)有机质、总氮对植物群落的分布影响较大。研究认为,典型水源地作为重要的功能区域,对其进行保护是维持卡山保护区生态平衡的一个重要环节。     

海南鹦歌岭轮叶三棱栎（Trigonobalanus verticillata）群落特征与保护对策

应用样方调查法,研究了中国分布新记录种——轮叶三棱栎(Trigonobalanus verticillata)种群结构及其所处森林群落特点。结果表明：轮叶三棱栎仅分布于海南鹦歌岭海拔1100~1400 m近山脊处的热带山地雨林及热带山地常绿阔叶林群落中,与陆均松(Dacrydium pectinatum)、海南阿丁枫（Altingia obovata）等树种伴生。在2个面积为1500 m2的调查样方中共记录了90种乔灌木树种,均匀度和Shannon-Wiener指数分别为0.81、0.86和3.20、3.27,轮叶三棱栎的重要值在群落中排在第9~10位;种群结构分析结果显示该种群数量小且无Ⅰ龄级和III龄级,属不稳定种群;轮叶三棱栎生态位宽度为1.69,在群落中仅排第19位,与陆均松和鸡毛松（Dacrycarpus imbricatus）的生态位重叠值分别为0.59和0.68,但与群落优势种的生态位重叠值多小于0.3。鹦歌岭在海拔1000 m以上具有较大面积的台地和人为破坏较少可能是该种群得以幸存的重要因素,加强就地保护,开展该种植物的生物学特性研究,并建立国家级保护区,将海南中部山区各保护区有机地联合在一起为保护良策。     

托木尔峰国家级自然保护区树附生地衣分布与环境关系的研究

为了查明新疆托木尔峰国家级自然保护区树附生地衣群落的空间分布规律,在保护区的不同海拔随机设计样点,进行树附生地衣的生态调查,以地衣盖度为指标应用典范对应分析揭示树附生地衣群落物种分布与环境因子之间的关系。结果表明,15个样点中共得出31种树附生地衣,地衣群落结构主要受海拔、湿度、郁闭度和光照强度的强烈影响,并随这些因素的变化表现出一定的空间差异,说明保护区附生地衣的群落变化和空间分布与这些环境因子高度相关。此外,某些地衣可能受全球暖化和气候干旱化的潜在威胁,增加森林盖度和生境湿度是保护地衣资源的有效措施。     

Application of ecological-niche factor analysis in habitat assessment of giant pandas

Ecological-niche factor analysis (ENFA) is a multivariate approach to study geographic distribution of species on a large scale with only “presence” data. It has been widely applied in many fields including wildlife management, habitat assessment and habitat prediction. In this paper, this approach was applied in habitat suitability assessment for giant pandas in Pingwu County, Sichuan Province, China. With “presence” data of giant pandas and remote sensing data, habitat suitability of pandas in this county was evaluated based on ENFA model, and spatial distribution pattern of nature reserves and conservation gaps were then evaluated. The results show that giant pandas in this county prefer high-elevation zones (> 2128 m) dominated by coniferous forest, and mixed coniferous and deciduous broadleaf forest, and avoid deciduous broadleaf forest and shrubs. Pandas avoid staying at habitats with human disturbances. Farmland is a major factor threatening panda habitat. Panda habitat is mainly distributed in north and west of Pingwu with a total area of 234033 hm², 106345hm² for suitable habitat and 127688 hm² for marginally suitable habitat). 3 nature reserves were located in Pingwu, covering over 49.2% of total suitable habitat and 45.6% of total marginally suitable habitat. Although 47.2% of panda habitat was in reserves under protection, connectivity between reserves was weak and a conservation gap existed in the north part of Pingwu. Thus, a new nature reserve in Baima and Mupi should be established to link the isolated habitats.     

Marine reserve design theory for species with ontogenetic migration

Models for marine reserve design have been developed primarily with ‘reef fish’ life histories in mind: sedentary adults in patches connected by larval dispersal. However, many fished species undertake ontogenetic migrations, such as from nursery grounds to adult spawning habitats, and current theory does not fully address the range of reserve options posed by that situation. I modelled a generic species with ontogenetic migration to investigate the possible benefits of reserves under three alternative scenarios. First, the fishery targets adult habitat, and reserves can sustain yields under high exploitation, unless habitat patches are well connected. Second, the fishery targets the nursery, and reserves are highly effective, regardless of connectivity patterns. Third, the fishery targets both habitats, and reserves only succeed if paired on adjacent, well-connected nursery and adult patches. In all cases, reserves can buffer populations against overexploitation but would not enhance fishery yield beyond that achievable by management without reserves. These results summarize the general situations in which management using reserves could be useful for ontogenetically migrating species, and the type of connectivity data needed to inform reserve design.     

A Test of the Higher-Taxon Approach in the Identification of Candidate Sites for Marine Reserves

Alternatives to species-level identification have been advocated as one solution to the problem of selecting marine reserves with limited information on the distribution of marine biodiversity.This study evaluated the effects on selection of candidate sites for marine reserves from using the higher-taxon approach as a surrogate for species-level identification of intertidal molluscs and rocky reef fishes. These effects were evaluated by determining the percentage of species included in candidate reserves identified from genus-, family- and order-level data by a complementarity-based reserve selection algorithm, and by testing for correlations between the irreplaceability values of locations. Candidate reserves identified from genus- and family-level data of intertidal molluscs included a similar percentage of all species as the reserves identified from species-level data. Candidate reserves selected from genus- and family-level data of rocky reef fishes included, respectively, 3–7% and 14–23% fewer species than reserves selected from species-level data. When the reserve identification process was constrained by a practical planning limit (a maximum of 20% locations able to be reserved) the reserves selected from genus- and family-level data of intertidal molluscs, and genus-level data of rocky reef fishes, included a similar percentage of species as the reserves identified from species-level data. Irreplaceability values of locations for species, genera and families of intertidal molluscs were highly correlated, and irreplaceability values of locations for species and genera of rocky reef fishes were highly correlated. This study suggests that genus- and family-level data for intertidal molluscs, and genus-level data for rocky reef fishes, are suitable surrogates for species in the identification of candidate sites for marine reserves.     

Nature reserve group planning for conservation of giant pandas in North Minshan, China

Formation of nature reserve groups (NRGs) is an important approach for optimising spatial patterns in nature reserves and for improving the efficiency of nature reserve networks. In this study, based on habitat evaluation and connectivity analysis, the approach and method for optimising spatial patterns and functional zoning of reserves were analysed using the case study of giant panda (Ailuropoda melanoleuca) reserves in North Minshan. Results indicated that five panda nature reserves had been established, which formed a reserve group and covered 48.4% of panda habitat and three of five population components. Although the nature reserves were connected to each other, core zones were divided into seven isolated areas. These divisions can reduce the efficiency of protecting giant pandas in reserve systems. To optimise spatial patterns in nature reserves, one new reserve is proposed and it is recommended that core zones be expanded and merged into two areas, in accordance with the spatial distribution of the panda population. Three linkage areas are also proposed—for facilitating panda exchange and movement among different populations. The study is expected to provide a scientific basis for planning the development of nature reserves in this mountain range, to promote the establishment of nature reserve groups in other areas, and to optimise entire nature reserve systems in China.     

Human density as an influence on species/area relationships: double jeopardy for small African reserves?

Small reserves are especially likely to lose species. Is that because the reserves are small, or because small reserves are located in especially adverse landscapes? It seems that the question has rarely, if ever, been asked. Data on reserve size and location in Africa, and calculations of local (within 50 km) mean human densities from available census records per province per country were the database here used to answer the question. IUCN grade I and II reserves in Africa are located across the range of human densities per country, including in regions of higher than average density. Furthermore reserve size correlates with local human density, such that small reserves are indeed significantly more likely than are large reserves to be located in regions of high human density (n = 169; P < 0.0001). However, while local human density correlates significantly with human-caused mortality of carnivores (the only taxon for which we had data), it does not correlate with detected extinctions in reserves in east Africa (the only region with available data). Rather, area of reserve is the main predictor. Nevertheless, abundant other evidence of the adverse effects of high human density on persistence of species and wilderness indicates that we need to take as a warning the findings reported here that small reserves occur in regions of high human density, and that human density correlates with human-caused mortality. They indicate that small reserves might face the double jeopardy of both their small size, and also their situation in especially hostile surroundings. In effect, small reserves are more isolated in more adverse habitat than current analyses in conservation biology, landscape ecology, or metapopulation analysis usually indicate.     

Effects of marine reserve characteristics on the protection of fish populations: a meta-analysis

Meta-analyses of published data for 19 marine reserves reveal that marine protected areas enhance species richness consistently, but their effect on fish abundance is more variable. Overall, there was a slight (11%) but significant increase in fish species number inside marine reserves, with all reserves sharing a common effect. There was a substantial but non-significant increase in overall fish abundance inside marine reserves compared to adjacent, non-reserve areas. When only species that are the target of fisheries were considered, fish abundance was significantly higher (by 28%) within reserve boundaries. Marine reserves vary significantly in the extent and direction of their response. This variability in relative abundance was not attributable to differences in survey methodology among studies, nor correlated with reserve characteristics such as reserve area, years since protection, latitude nor species diversity. The effectiveness of marine reserves in enhancing fish abundance may be largely related to the intensity of exploitation outside reserve boundaries and to the composition of the fish community within boundaries. It is recommended that studies of marine reserve effectiveness should routinely report fishing intensity, effectiveness of enforcement and habitat characteristics.     

Connectivity, Probabilities and Persistence: Comparing Reserve Selection Strategies

Reserve selection methods are often based on information on species’ occurrence. This can be presence–absence data, or probabilities of occurrence estimated with species distribution models. However, the effect of the choice of distribution model on the outcome of a reserve selection method has been ignored. Here we test a range of species distribution models with three different reserve selection methods. The distribution models had different combinations of variables related to habitat quality and connectivity (which incorporates the effect of spatial habitat configuration on species occurrence). The reserve selection methods included (i) a minimum set approach without spatial considerations; (ii) a clustering reserve selection method; and (iii) a dynamic approach where probabilities of occurrence are re-evaluated according to the spatial pattern of selected sites. The sets of selected reserves were assessed by re-computing species probability of occurrence in reserves using the best probability model and assuming loss of non-selected habitat. The results show that particular choices of distribution model and selection method may lead to reserves that overestimate the achieved target; in other words, species may seem to be represented but the reserve network may actually not be able to support them in the long-term. Instead, the use of models that incorporated connectivity as a variable resulted in the selection of aggregated reserves with higher potential for species long-term persistence. As reserve design aims at the long-term protection of species, it is important to be aware of the uncertainties related to model and method choice and their implications.     

No-take areas for sustainability of harvested species and a conservation invariant for marine reserves

Various kinds of no-take areas (refuges, reserves) are gaining attention as conservation tools. The efficacy of reserves can be considered from the perspectives of providing baseline data sets, protecting the stock, maximizing yield to the fishery, or some combination of these. Regardless of the measure of effectiveness of a reserve, practical application requires the development of techniques for settling operational and policy questions such as how large a reserve should be. A simple model, involving population growth and harvest, is used to explore how the fraction of habitat assigned to a reserve affects the sustainability of a take and to frame the trade-off between control of harvest outside of the reserve and the size of the reserve. This exploration also leads to the discovery of a robust conservation invariant for reserves.     

Reserve selection and persistence: complementing the existing Atlantic Forest reserve system

This study is an exercise to check the efficiency of the existing reserve system, and to show how systematic conservation planning—using information available and the complementarity concept—can improve the basis for decisions and minimize costs. We verified the performance, in number of cells and primate species representation, of the existing Atlantic Forest (Brazil) reserve network with a quarter-degree resolution grid, with 1,884 cells. We used occurrence data of 20 endemic primate species, and the maps of 237 existing reserves. Reserve networks were selected to represent primate species first considering no pre-existing reserves in Atlantic Forest, and then, considering the existing reserve system, taking into account the minimum area for viable population of the larger species (Northern muriqui Brachyteles hypoxanthus). Reserve selection was carried out using the complementarity concept implemented by a simulated annealing algorithm. Primate species representation (at least one occurrence in the network) could be achieved with 8% of the existing reserve system (nine cells in relation to the 120 in the existing reserve system). We found that today’s reserve system represents 89% of endemic primate species, excluding the species Coimbra Filho’s titi monkey (Callicebus coimbrai) and Marcgraf’s capuchin (Cebus flavius). The networks selected without considering existing reserves contained nine cells. The networks selected considering existing reserves (120 cells), had two new cells necessary to represent all the primates. This does not mean that a viable alternative is to start from zero (i.e., nonexistent reserves). Identifying critical supplementary areas using biodiversity information to fill the gaps and then starting “conservation in practice” in these areas should be priorities.     

Would climate change drive species out of reserves? An assessment of existing reserve‐selection methods

Concern for climate change has not yet been integrated in protocols for reserve selection. However if climate changes as projected, there is a possibility that current reserve‐selection methods might provide solutions that are inadequate to ensure species' long‐term persistence within reserves. We assessed, for the first time, the ability of existing reserve‐selection methods to secure species in a climate‐change context. Six methods using a different combination of criteria (representation, suitability and reserve clustering) are compared. The assessment is carried out using European distributions of 1200 plant species and considering two extreme scenarios of response to climate change: no dispersal and universal dispersal. With our data, 6–11% of species modelled would be potentially lost from selected reserves in a 50‐year period. Measured uncertainties varied in 6% being 1–3% attributed to dispersal assumptions and 2–5% to the choice of reserve‐selection method. Suitability approaches to reserve selection performed best, while reserve clustering performed poorly. We also found that 5% of species modelled would lose their entire climatic envelope in the studied area; 2% of the species modelled would have nonoverlapping distributions; 93% of the species modelled would maintain varying levels of overlapping distributions. We conclude there are opportunities to minimize species' extinctions within reserves but new approaches are needed to account for impacts of climate change on species; especially for those projected to have temporally nonoverlapping distributions.