中国生物多样性就地保护成效与展望

生物多样性就地保护是指通过开展自然保护地体系的建立与管理, 结合自然保护地以外其他有效的基于区域的保护措施(other effective area-based conservation measures, OECMs), 从而实现物种种群及其栖息地的保护与恢复以及保障和提升生态系统服务的目标。就地保护是实现2020年全球生物多样性保护目标最为重要的措施之一。本文从自然保护地数量与面积、代表性、有效性, 以及其他生物多样性就地保护措施等方面, 整理和综述了国内外近年来的相关报道。总体来看, 我国基本建立了具有中国特色的生物多样性就地保护与管理体系, 实施了各项生物多样性保护恢复措施, 取得了一系列重大进展。自然保护地的面积和数量均呈现上升趋势, 已覆盖陆域国土面积的18%, 对一些重要生态系统及重点保护物种的保护取得了一定成效。正在建设的10处国家公园体制试点提升了部分重点物种的保护连通性。自然保护区总体管理状况相对较好, 保护了90%以上的哺乳动物和97%的兰科植物。此外, 其他有效的基于区域的保护措施亦为生物多样性就地保护贡献了民间力量。在此基础上, 本文对照《中国生物多样性保护战略与行动计划(2011-2030年)》中对“加强生物多样性就地保护”的各项要求, 分析总结了当前我国生物多样性就地保护仍然存在的问题与不足, 具体表现在以下几个方面: 自然保护地整体保护能力仍有待提升; 生物多样性保护优先区域仍然存在保护空缺; 自然保护区管理质量有待提升; 缺乏公共协商机制; 自然保护地以外的其他就地保护工作仍在探索阶段等。在此基础上, 对将来我国生物多样性就地保护提出了进一步建议与展望: (1)制定更为具体和量化的生物多样性就地保护目标; (2)加大力度减少物种受威胁程度, 特别是受关注较少的物种; (3)以保障和提升生态系统服务为目标, 提升生态系统保护修复的系统性与整体性; (4)加强自然保护地以外的生物多样性就地保护; (5)完善长期监测体系, 为生物多样性就地保护成效评估提供数据支撑。本文可为“2020年后全球生物多样性框架”特别是就地保护目标的制定与实施提供参考。     

湖泊沉积植物古DNA的现代过程

对植被历史变化过程的研究是理解现代植被组成、分布及其对全球变化响应的基础。近年来, 随着分子古生态学的发展, 分析沉积介质中的陆生植物古DNA信号, 以研究植被及植物多样性演变的历史过程正在成为研究热点, 湖泊沉积植物古DNA已成为古植被和古生态学研究的成熟代用指标。然而与第四纪孢粉分析相比较, 湖泊沉积植物古DNA的现代过程依然不明确, 成为其进一步发展和应用的限制因素。基于此, 该文综述了湖泊沉积植物古DNA技术研究进展, 尝试阐明湖泊沉积植物古DNA的现代过程, 包括植物DNA的来源、沉积和保存过程及其影响因素, 以及植物DNA与现代植被的关系等。已有研究表明, 湖泊沉积植物古DNA主要来自湖泊周边或流域范围, 其丰度和组成除受到源植物生物量的影响外, 同样受到沉积物的搬运和沉积过程中DNA降解作用、土壤以及沉积物中颗粒的吸附过程和稀释作用等因素的影响。湖泊沉积物中植物DNA的保存则主要受到微生物活动、湖水的化学性质(电导率和pH值)、湖泊深度、沉积物组成等一系列生物与非生物因素的共同影响。湖泊沉积植物古DNA可以揭示其沉积时代的植物群落类型以及气候环境信息, 但目前并不能够用来定量重建古植被变化过程。鉴于湖泊沉积植物古DNA现代过程的复杂性, 对研究结果的解释要格外小心。与孢粉分析相比, 湖泊沉积植物古DNA研究仍处于起步阶段, 但随着分子生物技术的进步、实验设计的优化、物种条形码的扩充及参考数据库的完善等, 以DNA宏条形码和宏基因组学为主要技术手段的植物古DNA技术, 必将推动我国植物古生态研究的进一步发展。     

GPS collars have an apparent positive effect on the survival of a large carnivore

Are instrumented animals representative of the population, given the potential bias caused by selective sampling and the influence of capture, handling and wearing bio-loggers? The answer is elusive owing to the challenges of obtaining comparable data from individuals with and without bio-loggers. Using non-invasive genetic data of a large carnivore, the wolverine (Gulo gulo) in Scandinavia, and an open-population spatial capture–recapture model, we found a 16 (credible interval: 4–30) percentage points lower mortality probability for GPS-collared individuals compared with individuals without GPS collars. While the risk of dying from legal culling was comparable for collared and non-collared wolverines, the former experienced lower probability of mortality due to causes other than legal culling. The aforementioned effect was pronounced despite a potentially lower age—and therefore likely higher natural mortality—of collared individuals. Reports of positive effects of bio-loggers on the survival of individuals are uncommon and we argue that GPS collars could shield animals from poaching. Our results highlight the challenges of drawing population-level inferences for populations subjected to poaching when using data from instrumented individuals.     

Distribution patterns of biodiversity and the design of a representative reserve network in Portugal

Representativeness is a desirable property of conservation networks. In this paper an attempt is made to assess the efficiency of current conservation networks in Portugal in representing vertebrates (reptiles and amphibians) and plants (gymnosperms, pteridophytes and bryophytes). It was found that whilst the protected areas do not sample all species in the database they provide a better result than choosing areas at random. For the goal of maximizing representation of taxa per unit area hotspots and complementarity performed better. A pattern of over-representation of vertebrates in relation to lower plants was discovered among selected conservation areas in Portugal suggesting that charismatic organisms with large home ranges may not always be the most appropriate surrogates for biodiversity when representativeness is sought. When trying to fill the gaps in current protected areas with additional areas only complementarity performed better than choosing areas at random. Both rarity and richness hotspots gave worse results. Opportunistic administrative criteria such as supplementing the PAS with other conservation areas (CORINE Biotopes) without taking into account their contribution to a representation goal was nearly half as good as choosing areas at random. The results recall for the need of explicit goals and accountable methods in area selection for conservation and reinforce the role of complementarity for finding additional areas to protected areas when limited resources are available for ‘in situ’ conservation.     

The MAD legacy: How meaningful is mean age-at-death in skeletal samples

This study examines the representativeness of palaeodemographic reconstructions from human skeletal remains. Mean age-at-death (MAD) is the primary statistic used in interpretations of changing patterns of health and well being from palaeodemographic analyses. A series of sampling experiments were conducted on three documented 19th century samples representing the total cemetery population from which skeletal samples could be drawn. Comparisons of the age-at-death distributions of simulated skeletal samples to the parent population were made to assess the relative magnitude of deviation associated with different types of bias (age, sex, temporal). From the examples presented, variability in age-at-death distribution is high in samples of less than 100, suggesting that for samples of less than 100analyzable individuals, it is probable that the mortality profiles constructed are not an accurate reflection of the cemetery. It is proposed that whateverprocess mean age-at-death reflects for past populations (fertility or mortality), is irrelevant if the sample on which the statistic is calculated is not representative of the population. Given that most cemetery samples will be subject, differentially, to biases at a variety of levels, comparative studies based on palaeodemographic data cannot be considered reliablewithout careful control for those biases. It is suggested that representativeness is the primary theoretical obstacle for researches to overcome, and that it is necessary to shift our focus to rigorously exploring those factors that bias our samples. Without some direct quantification of the representativeness of a sample, palaeodemographic estimators such as mean age-at-death are meaningless and any subsequent interpretations regarding the past, dubious at best.     

The efficiency of indicator groups for the conservation of amphibians in the Brazilian Atlantic Forest

The adequate selection of indicator groups of biodiversity is an important aspect of the systematic conservation planning. However, these assessments differ in the spatial scales, in the methods used and in the groups considered to accomplish this task, which generally produces contradictory results. The quantification of the spatial congruence between species richness and complementarity among different taxonomic groups is a fundamental step to identify potential indicator groups. Using a constructive approach, the main purposes of this study were to evaluate the performance and efficiency of eight potential indicator groups representing amphibian diversity in the Brazilian Atlantic Forest. Data on the geographic range of amphibian species that occur in the Brazilian Atlantic Forest were overlapped to the full geographic extent of the biome, which was divided into a regular equal‐area grid. Optimization routines based on the concept of complementarily were applied to verify the performance of each indicator group selected in relation to the representativeness of the amphibians in the Brazilian Atlantic Forest as a whole, which were solved by the algorithm “simulated annealing,” through the use of the software MARXAN. Some indicator groups were substantially more effective than others in regard to the representation of the taxonomic groups assessed, which was confirmed by the high significance of the data (F = 312.76; P < 0.01). Leiuperidae was considered as the best indicator group among the families analyzed, as it showed a good performance, representing 71% of amphibian species in the Brazilian Atlantic Forest (i.e., 290 species), which may be associated with the diffuse geographic distribution of their species. In this sense, this study promotes understanding of how the diversity standards of amphibians can be informative for systematic conservation planning on a regional scale.     

生态系统保护现状及保护等级评估——以江西省为例

基于生态系统的保护是防止生物多样性丧失的重要手段,已成为保护生物学研究的热点。对生态系统保护等级进行划分,确定局域、区域和全球尺度上生态系统保护的优先性,可为制定生态系统保护方案提供重要依据。目前,生态系统保护等级划分的常用指标包括面积流失率、幅度和代表性。以江西省生态系统为例,基于20世纪80年代的江西省植被图、生态系统图、2010年土地利用图和自然保护区图,在GIS环境下进行图层叠加运算和重分类,再进行定量评估和归一化,将江西省生态系统划分为极重要、重要和一般3个级别。结果表明:过去的30年间江西省自然生态系统面积共减少了82613.83km2,减少率超过了60%。全省的37个自然生态系统类型中有19个类型建有国家级自然保护区,但得到保护的面积比例较低。森林生态系统中极重要、重要和一般生态系统类型分别占省国土面积的16.7374%、5.5310%和3.8242%,受国家级自然保护区保护的比例分别为0.51%、3.73%和5.76%;灌丛生态系统中极重要、重要和一般生态系统类型分别占0.0975%、0.9335%和0.0100%,保护比例分别为1.72%、0.17%和0.70%;草地生态系统中极重要、重要和一般生态系统类型分别占0.2647%、0.0005%和0.1064%,保护比例分别为0.21%、0.00%和3.49%;湿地生态系统中极重要、重要和一般生态系统类型分别占0.3532%、0.0345%和1.5650%,保护比例分别为1.87%、0.00%和18.01%。从各级生态系统空间分布来看,极重要生态系统分布范围最广,主要分布在江西省的东南部和西北部;重要生态系统主要分布在西北部和东北部;一般生态系统分布范围最小,主要分布在北部。中部地区的自然生态系统多数由于经济发展而退变为农田、城市等人工生态系统。结合江西省生态系统现状,将极重要的生态系统作为重点保护范围,因而占江西省国土面积17.46%的生态系统应该得到优先保护。这一结果为有效地开展生态系统管理,制定有针对性的生态系统的保护规划具有重要参考价值。     

温带森林乔木生物量估算:Logistic模型优于Allometric模型

作为研究森林生态系统结构与功能的基础要素,准确估算植被生物量关乎温室气体减排政策制定,以及区域气候稳定性评估,具有显著的科学意义和社会需求。Allometric模型提供了量化生物量与个体体型关系的简洁数学形式,但其幂函数结构描述了生物量持续加速且无限增长,与随植株增大而不断加剧的种内种间竞争和资源限制相悖。然而,当前严重缺失大体型植株的不合理样本结构部分掩盖了模型缺陷,是造成该模型获得重复验证的重要潜在原因。相较而言,通过引入限制因子,Logistic模型同时具备描述高速增长和后期渐趋收敛的模型特征,却鲜被用于植被生物量估算。因此,本研究搜集了典型植被类型--温带森林乔木生物量相关的197篇已发表文献（1945-2016年）,基于198种针阔叶乔木物种总计26402个叶、茎和地上部分生物量数据,采用Logistic模型分析了生物量随胸径增长的变化规律。结果表明,较之Allometric模型（R^2* 0.76、RMSE 0.44 g、AIC 7189.9）,Logistic模型呈现更好的拟合优度（R^2* 0.81、RMSE 0.39 g、AIC 5809.1）。此外,Logistic模型计算了平衡生物量与平衡生长率,以反映与生境资源相适应的植株生物量及其累积速率,通过识别生物量渐趋稳定的胸径阈值,发现超过该拐点的大体型样本占比不足0.71%,呈现显著的生态学意义。综上,Logistic模型估算温带森林乔木生物量具备统计效力和理论优势。研究显著改进了植被生物量估算模型,有助于揭示植物碳蓄积策略,了解森林能流规律和碳库动态,为制定气候变化应对政策提供依据。     

Heterogeneity‐constrained random resampling of phytosociological databases

Aim: Phytosociological databases often contain unbalanced samples of real vegetation, which should be carefully resampled before any analyses. We propose a new resampling method based on species composition, called heterogeneity‐constrained random (HCR) resampling. Method: Many subsets of the source vegetation database are selected randomly. These subsets are sorted by decreasing mean dissimilarity between pairs of the vegetation plots, and then sorted again by increasing variance of these dissimilarities. Ranks from both sortings are summed for each subset, and the subset with the lowest summed rank is considered as the most representative. The performance of this method was tested using simulated point patterns that represented different levels of aggregation of vegetation plots within a database. The distributions of points in the subsets resulting from different resampling methods, both with and without database stratification, were compared using Ripley's K function. The mean of random selections from an unbiased sample was used as a reference in these comparisons. The efficiency of the method was also demonstrated with real phytosociological data. Results: Both stratified and HCR resampling yielded selection patterns more similar to the reference than resampling without these tools. Outcomes from the resampling that combined these two methods were the most similar to the reference. The efficiency of the HCR resampling method varied with different levels of aggregation in the database. Conclusions: This new method is efficient for resampling phytosociological databases. As it only uses information on species occurrences/abundances, it does not require the definition of strata, thereby avoiding the effect of subjective decisions on the selection outcome. Nevertheless, this method can also be applied to stratified databases.