基于InVEST-图论模型的西双版纳州亚洲象生境网络评价

在大力推进生物多样性保护工作的背景下,亚洲象的活动范围与人类生产生活空间不断重叠,人象冲突矛盾日益严重,对物种栖息地生境网络进行优化能从源头缓解这一矛盾。在亚洲象国家公园建设之际,研究以西双版纳州为例,提出了一种基于InVEST-图论复合模型识别并优化生境网络的方法:即以土地利用数据为基础,结合亚洲象生活习性与栖息地偏好,通过海拔、坡度、距水源距离3个约束因子矫正生境质量数据,运用Graphab软件识别潜在生境网络,结合最小累积阻力模型理念与景观图论的分析方法,从"源地-廊道"角度定量化分析西双版纳州国家级亚洲象保护区的保护空缺,探讨保护区的空间布局优化策略与生境分级保护策略,以期为亚洲象国家公园的建设与西双版纳州国土空间规划提供新视角。结果表明,西双版纳州共识别出生态源地335个,总面积4595.60km²,总体上高质量生境分布较为均衡,连通性较好的生境网络集中分布在北部与东部区域,中部B4勐仑片区存在较为显著的生态孤岛现象,西南部高质量生境斑块小而破碎,联系紧密但缺少作为核心栖息地的大面积生境。保护空缺方面,国家级保护区范围内的生态源地仅占总源地面积的31.68%,大型保护空缺集中分布于B3勐养片区东北部;优化后的生境网络能形成以B3勐养片区为核心,以国家自然保护区为主的"B5-A-B3-B4-B1-B2"生物迁徙廊道。     

The effects of habitat fragmentation via forestry plantation establishment on spatial genotypic structure in the small marsupial carnivore, Antechinus agilis

Dispersal is an important influence on species' distributions, patch colonization and population persistence in fragmented habitat. We studied the impacts of habitat fragmentation resulting from establishment of an exotic pine plantation on dispersal of the marsupial carnivore, Antechinus agilis. We applied spatial analyses of individual multilocus microsatellite genotypes and mitochondrial haplotypes to study patterns of gene flow in fragmented habitat and natural habitat 'control' areas, and how this is affected by the spatial dispersion of habitat patches, the presence of corridors and a 'mainland' source of migrants. Spatial analysis of molecular variance and partial Mantel tests confirmed the absence of cryptic barriers to gene flow in continuous habitat, which if present would confound the comparison of genetic structures in fragmented vs. unfragmented habitats. Spatial genotypic structure suggested that although dispersal was male-biased in both habitat types, fragmentation restricted dispersal of males more than that of females and the degree of restriction of male dispersal was dependent on the geographical isolation of the patch. The scale of positive genotypic structure in fragmented habitat was restricted to the two closest patches for females and the three closest patches for males. Our results provide evidence for significantly increased gene flow through habitat corridors relative to that across the matrix and for significantly lower gene flow between 'mainland' unfragmented habitat and habitat patches relative to that within either habitat type, suggesting a behavioural barrier to crossing habitat interfaces.     

Understanding the effect of landscape fragmentation and vegetation productivity on elephant habitat utilization in Amboseli ecosystem,Kenya

Understanding factors affecting the distribution of the African elephant is important for its conservation in increasingly human‐dominated savannah landscapes. However, understanding how landscape fragmentation and vegetation productivity affect elephant habitat utilization remains poorly understood. In this study, we tested whether landscape fragmentation and vegetation productivity explain elephant habitat utilization in the Amboseli ecosystem in Kenya. We used GPS (Global Positioning System) telemetry data from five elephants to quantify elephant habitat utilization. Habitat utilization was determined by calculating the time elephants spent within a unit area. We then used generalized additive models (GAMs) to model the relationship between time density and landscape fragmentation, as well as vegetation productivity. Results show that landscape fragmentation and vegetation productivity significantly (P < 0.05) explain elephant habitat utilization. A significant (P < 0.05) unimodal relationship between vegetation productivity and habitat utilization was observed. Results suggest that elephants spend much of their time in less fragmented landscapes of intermediate productivity.     

生境破碎化过程对流域生境质量的影响

近几十年来,随着工业化、城市化的加速推进,人类活动对自然生境的干扰越来越频繁,导致生境破碎化与生境质量下降。在流域尺度上科学模拟生境破碎化过程及其对生境质量的影响,对于提升生物多样性和生态系统功能具有重要意义。以鄱阳湖流域为研究区域,基于InVEST模型分析区域生境质量的演变特征;从生境面积、生境边缘和生境隔离三个特征维度模拟生境破碎化过程;采用广义加性模型和地理探测器探究不同生境破碎化过程对生境质量变化的影响与交互作用。研究结果表明:(1)鄱阳湖流域生境质量呈下降趋势,从2000年的0.7862下降到2010年的0.7807,再下降到2020年的0.7715,但总体生境质量较好。生境质量较优的区域主要分布在流域南部、东北部以及西部地区,生境质量较差的区域主要分布在各个子流域的交界处。(2)2000-2010年,鄱阳湖流域生境面积占比下降、生境边缘增加和生境隔离增加三个生境破碎化过程分别占总研究区网格数的34.70%、30.15%和4.50%;2010-2020年分别占总研究区网格数的34.80%、30.69%和4.40%;2000-2020年分别占总研究区网格数的40.82%、37.50%和5.46%。生境面积减少的网格主要集中在鄱阳湖流域的中北部地区;生境边缘增加的网格分布和生境面积减少的网格分布相似;相比之下,生境隔离增加的网格较少,主要分布在各城市的中心城区范围。(3)生境破碎化过程对生境质量具有显著影响,两者呈非线性负相关关系;三个生境破碎化过程两两之间交互作用对生境质量的影响呈现双因子增强趋势。研究结果可为鄱阳湖流域生态格局优化与生境质量提升提供科学参考。     

Using presence‐only modelling to predict Asian elephant habitat use in a tropical forest landscape: implications for conservation

Aim Asian elephants, Elephas maximus, are threatened throughout their range by a combination of logging, large scale forest conversion and conflict with humans. We investigate which environmental factors, both biotic and abiotic, constrain the current distribution of elephants. A spatially explicit habitat model is constructed to find core areas for conservation and to assess current threats. Location Ulu Masen Ecosystem in the province of Nanggroe Aceh Darussalam on the island of Sumatra, Indonesia. Methods A stratified survey was conducted at 12 sites (300 transects) to establish the presence of elephants. Presence records formed the basis to model potential habitat use. Ecological niche factor analysis (ENFA) is used to describe their niche and to identify key factors shaping elephant distribution. An initial niche model was constructed to describe elephant niche structure, and a second model focused on identifying core areas only. To assess the threat of habitat encroachment, overlap between the elephants’ optimal niche and the occurrence of forest encroachment is computed. Results Elephants were recorded throughout the study area from sea level to 1600 m a.s.l. The results show that the elephant niche and consequently habitat use markedly deviates from the available environment. Elephant presence was positively related to forest cover and vegetation productivity, and elephants were largely confined to valleys. A spatially explicit model showed that elephants mainly utilize forest edges. Forest encroachment occurs throughout the elephants range and was found within 80% of the elephants’ ecological niche. Main conclusions In contrast to general opinion, elephant distribution proved to be weakly constrained by altitude, possibly because of movement routes running through mountainous areas. Elephants were often found to occupy habitat patches in and near human‐dominated areas. This pattern is believed to reflect the displacement of elephants from their former habitat.     

岷山地区大熊猫生境评价与保护对策研究

综合运用大熊猫生物学与行为生态学研究成果、遥感数据分析与地理信息系统技术 ,在系统研究岷山地区大熊猫生境分布、生境质量与空间格局的基础上 ,明确岷山地区保护大熊猫的关键区域 ,分析岷山地区大熊猫保护与自然保护区建设的对策 ,以期为岷山地区大熊猫保护及其与岷山地区资源开发与发展的协调提供依据。遥感数据分析结果表明 ,岷山地区以森林为主 ,各类森林面积 1 91 790 3.4 4 hm2 ,占 5 5 .4 2 % ,将与大熊猫生境密切相关的森林植被分为常绿阔叶林、落叶阔叶林、针阔混交林、亚高山针叶林等 ,其中亚高山针叶林面积 5 380 4 9.6 4 hm2 ,占全部森林的占 2 8.0 5 % ,落叶阔叶林面积 4 6 1 35 5 .6 7hm2 ,占2 4 .0 6 % ,针阔混交林面积 4 0 30 36 .2 6 hm2 ,占 2 1 .0 1 %。结果表明岷山地区有大熊猫潜在生境 1 32 3789.1 5 hm2 ,由于森林资源利用、交通、农业活动影响、居民薪柴砍伐 ,以及生境破碎化与生境隔离等导致的生境丧失 5 5 341 3.4 5 hm2 ,目前尚存的大熊猫适宜生境 770 375 .7hm2 ,由于交通等隔离而成为至少 5个相互分隔的生境单元 ,大熊猫种群交流受到严重阻碍。为了有效地保护岷山大熊猫 ,首先应充分注意到各种人类活动 ,尤其交通的建设对大熊猫生境的影响 ;其次要扩大自然保护区范围 ,     

Dispersal capacity and diet breadth modify the response of wild bees to habitat loss

Habitat loss poses a major threat to biodiversity, and species-specific extinction risks are inextricably linked to life-history characteristics. This relationship is still poorly documented for many functionally important taxa, and at larger continental scales. With data from five replicated field studies from three countries, we examined how species richness of wild bees varies with habitat patch size. We hypothesized that the form of this relationship is affected by body size, degree of host plant specialization and sociality. Across all species, we found a positive species–area slope (z = 0.19), and species traits modified this relationship. Large-bodied generalists had a lower z value than small generalists. Contrary to predictions, small specialists had similar or slightly lower z value compared with large specialists, and small generalists also tended to be more strongly affected by habitat loss as compared with small specialists. Social bees were negatively affected by habitat loss (z = 0.11) irrespective of body size. We conclude that habitat loss leads to clear shifts in the species composition of wild bee communities.     

Vulnerability of ecosystems to climate change moderated by habitat intactness

The combined effects of climate change and habitat loss represent a major threat to species and ecosystems around the world. Here, we analyse the vulnerability of ecosystems to climate change based on current levels of habitat intactness and vulnerability to biome shifts, using multiple measures of habitat intactness at two spatial scales. We show that the global extent of refugia depends highly on the definition of habitat intactness and spatial scale of the analysis of intactness. Globally, 28% of terrestrial vegetated area can be considered refugia if all natural vegetated land cover is considered. This, however, drops to 17% if only areas that are at least 50% wilderness at a scale of 48 × 48 km are considered and to 10% if only areas that are at least 50% wilderness at a scale of 4.8 × 4.8 km are considered. Our results suggest that, in regions where relatively large, intact wilderness areas remain (e.g. Africa, Australia, boreal regions, South America), conservation of the remaining large‐scale refugia is the priority. In human‐dominated landscapes, (e.g. most of Europe, much of North America and Southeast Asia), focusing on finer scale refugia is a priority because large‐scale wilderness refugia simply no longer exist. Action to conserve such refugia is particularly urgent since only 1 to 2% of global terrestrial vegetated area is classified as refugia and at least 50% covered by the global protected area network.     

Short‐term differences in animal assemblages in patches formed by loss and growth of habitat

Ecological theory predicts that habitat growth and loss will have different effects on community structure, even if they produce patches of the same size. Despite this, studies on the effects of patchiness are often performed without prior knowledge of the processes responsible for the patchiness. We manipulated artificial seagrass habitat in temperate Australia to test whether fish and crustacean assemblages differed between habitats that formed via habitat loss and habitat growth. Habitat loss treatments (originally 16 m²) and habitat growth treatments (originally 0 m²) were manipulated over 1 week until each reached a final patch size of 4 m². At this size, each was compared through time (0–14 days after manipulation) with control patches (4 m² throughout the experiment). Assemblages differed significantly among treatments at 0 and 1 day after manipulation, with differences between growth and loss treatments contributing to most of the dissimilarity. Immediately after the final manipulation, total abundance in habitat loss treatments was 46% and 62% higher than controls and habitat growth treatments, respectively, which suggests that animals crowded into patches after habitat loss. In contrast to terrestrial systems, crowding effects were brief (≤1 day), signifying high connectivity in marine systems. Growth treatments were no different to controls, despite the lower probability of animals encountering patches during the growth phase. Our study shows that habitat growth and loss can cause short‐term differences in animal abundance and assemblage structure, even if they produce patches of the same size.     

南滚河流域土地利用变化对亚洲象生境的影响

土地利用变化对亚洲象生境影响显著,明晰其影响机制是有效保护亚洲象的前提。为探明土地利用变化对亚洲象生境影响的时空过程及机制,以亚洲象残存的中-缅跨境流域-南滚河流域为例,在1988和2018年两期Landsat土地利用/土地覆被遥感分类图的基础上,采用LandTrendr算法检测30年间流域土地利用变化引起的天然林扰动,结合生态位因子分析（ENFA）模型评定的亚洲象生境适宜性分布,探究以天然林扰动为主的土地利用变化对亚洲象生境的影响。结果表明：（1）1988-2018年间,南滚河流域土地利用变化主要为天然林转化为其他地类,且天然林扰动强度在中、缅境内差异明显;（2）以橡胶种植扩张导致毁林为主的土地利用变化造成南滚河流域亚洲象生境萎缩,生境斑块间连通性降低,破碎化程度较高;（3）该流域亚洲象生境丧失过程表现为由边缘向内部逐渐被蚕食,适宜生境最终被分割为上、下游两个相互孤立的子区域。因此,抑制以橡胶林为主的热作种植扩张,恢复上、下游生境连通性,建立流域尺度的跨境保护区,是实现南滚河流域亚洲象种群保护和缓解人象冲突的重要途径。     

Evaluating performance of aerial survey data in elephant habitat modelling

Aerial survey data are widely used to model distribution of wildlife. However, their performance in habitat modelling remains largely untested. We used aerial survey and satellite‐linked Global Positioning System (GPS) collar data for elephants, to test (i) whether there is an optimal spatial resolution of predictor variables at which habitat models based on aerial survey data that are uncorrected for locational error can accurately predict elephant habitat and (ii) whether habitat models based on these data sets can accurately predict the presence of elephants in closed woodland habitats. We applied maximum entropy modelling (Maxent) to these data sets and used the Normalised Difference Vegetation Index (NDVI) as well as distance from water points as the habitat predictors to answer these questions. Our results demonstrate better ability of aerial survey data to predict elephant presence at the coarser spatial resolution of 1000 m of both predictor variables. Habitat models derived from aerial survey data underpredicted elephant presence in more closed woodland habitats than those derived from GPS collar data. This result implies that elephants located under dense tree canopies are likely missed during an aerial survey. Our study is one of the first to empirically test and report results on the poor performance of aerial survey data in habitat modelling especially in dense woodlands.     

黑龙江省完达山地区马鹿生境破碎化及其影响因子

应用景观生态学原理和地理信息系统技术,分析黑龙江省完达山地区马鹿生境相关因子重要性、对景观连接度进行模糊相对赋值,建立了景观连接度评价模型及景观斑块指数,研究了黑龙江省完达山地区关于马鹿生境的景观连接度水平、生境的适宜性以及景观的空间结构。结果表明:(1)在155.6km2的面积中,适宜地区的总面积仅为14.81km2,占研究地区的9.52%;次适宜地区的总面积为9.57km2,占研究地区的6.15%;一般适宜地区的总面积为130.05km2,占研究地区的83.58%;不适宜地区的总面积为1.17km2,占研究地区的0.75%;(2)研究地区马鹿各类适宜地区呈多个斑块且相互隔离,在空间分布上处于破碎状态,而且不适宜地区斑块(人为活动景观)的面积比例虽小,在生态系统中形态上的破碎化程度较小,但对马鹿的生境的生态功能的丧失起到重要作用。     

Temporal transferability of wildlife habitat models: implications for habitat monitoring

Aim Temporal transferability is an important issue when habitat models are used beyond the time frame corresponding to model development, but has not received enough attention, particularly in the context of habitat monitoring. While the combination of remote sensing technology and habitat modelling provides a useful tool for habitat monitoring, the effect of incorporating remotely sensed data on model transferability is unclear. Therefore, our objectives were to assess how different satellite‐derived variables affect temporal transferability of habitat models and their usefulness for habitat monitoring. Location Wolong Nature Reserve, Sichuan Province, China. Methods We modelled giant panda habitat with the maximum entropy algorithm using panda presence data collected in two time periods and four different sets of predictor variables representing land surface phenology. Each predictor variable set contained either a time series of smoothed wide dynamic range vegetation index (WDRVI) or 11 phenology metrics, both derived from single‐year or multi‐year (i.e. 3‐year) remotely sensed imagery acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS). We evaluated the ability of models obtained with these four variable sets to predict giant panda habitat within and across time periods by using threshold‐independent and threshold‐dependent evaluation methods and five indices of temporal transferability. Results Our results showed that models developed with the four variable sets were all useful for characterizing and monitoring giant panda habitat. However, the models developed using multi‐year data exhibited significantly higher temporal transferability than those developed using single‐year data. In addition, models developed with phenology metrics, especially when using multi‐year data, exhibited significantly higher temporal transferability than those developed with the time series. Main conclusions The integration of land surface phenology, captured by high temporal resolution remotely sensed imagery, with habitat modelling constitutes a suitable tool for characterizing wildlife habitat and monitoring its temporal dynamics. Using multi‐year phenology metrics reduces model complexity, multicollinearity among predictor variables and variability caused by inter‐annual climatic fluctuations, thereby increasing the temporal transferability of models. This study provides useful guidance for habitat monitoring through the integration of remote sensing technology and habitat modelling, which may be useful for the conservation of the giant panda and many other species.     

野双峰驼各分布区的生存环境差异及评价

世界上野双峰驼(Camelus bactrianus ferus)目前仅分布于中国新疆境内及中蒙边境,即：中国新疆的塔克拉玛干沙漠、阿尔金山北麓、戛顺戈壁、中蒙边境及蒙古国西部的外阿尔泰戈壁。总数共计730～880头。目前已为极度濒危物种。本文对野驼在不同分布区由于生境及人类活动影响所造成的差异加以对比研究并进行评价,为野骆驼保护提供依据。     

The importance of fine‐scale predictors of wild boar habitat use in an isolated population

1. Predicting the likelihood of wildlife presence at potential wildlife–livestock interfaces is challenging. These interfaces are usually relatively small geographical areas where landscapes show large variation over small distances. Models of wildlife distribution based on coarse data over wide geographical ranges may not be representative of these interfaces. High‐resolution data can help identify fine‐scale predictors of wildlife habitat use at a local scale and provide more accurate predictions of species habitat use. These data may be used to inform knowledge of interface risks, such as disease transmission between wildlife and livestock, or human–wildlife conflict.
2. This study uses fine‐scale habitat use data from wild boar (Sus scrofa) based on activity signs and direct field observations in and around the Forest of Dean in Gloucestershire, England. Spatial logistic regression models fitted using a variant of penalized quasi‐likelihood were used to identify habitat‐based and anthropogenic predictors of wild boar signs.
3. Our models showed that within the Forest of Dean, wild boar signs were more likely to be seen in spring, in forest‐type habitats, closer to the center of the forest and near litter bins. In the area surrounding the Forest of Dean, wild boar signs were more likely to be seen in forest‐type habitats and near recreational parks and less likely to be seen near livestock.
4. This approach shows that wild boar habitat use can be predicted using fine‐scale data over comparatively small areas and in human‐dominated landscapes, while taking account of the spatial correlation from other nearby fine‐scale data‐points. The methods we use could be applied to map habitat use of other wildlife species in similar landscapes, or of movement‐restricted, isolated, or fragmented wildlife populations.