Polymorphic microsatellites for the study of fragmented populations of Pitcairnia geyskesii L. B. Smith (Bromeliaceae), a specific saxicolous species of inselbergs in French Guiana

Pitcairnia geyskesii is a saxicolous bromeliad endemic to the granitic inselbergs of French Guiana and Surinam. Seven polymorphic microsatellite markers were characterized to investigate the polymorphism among individuals sampled on five inselbergs in French Guiana. The total number of alleles per locus varied from four to 14. Mean observed heterozygosities at each microsatellite locus ranged from 0.114 to 0.629. This set of microsatellites offers an efficient tool for more detailed investigations on the genetic structure of fragmented populations living on such a singular and insular habitat within tropical rainforest.     

Spandrels and a pervasive problem of evidence

Evolutionary biology, indeed any science that attempts to reconstruct prehistory, faces practical limitations on available data. These limitations create the problem of contrast failure: specific observations may fail to discriminate between rival evolutionary hypotheses. Assessing the risk of contrast failure provides a way to evaluate testing protocols in evolutionary science. Here I will argue that part of the methodological critique in the Spandrels paper involves diagnosing contrast failure problems. I then distinguish the problem of contrast failure from the more familiar philosophical problem of underdetermination, and demonstrate how contrast failure arises in scientific practice with an investigation into Lewontin and White’s (Evolution 14:116–129, 1960) estimation of an adaptive landscape.

Prospects for tropical forest biodiversity in a human-modified world

The future of tropical forest biodiversity depends more than ever on the effective management of human-modified landscapes, presenting a daunting challenge to conservation practitioners and land use managers. We provide a critical synthesis of the scientific insights that guide our understanding of patterns and processes underpinning forest biodiversity in the human-modified tropics, and present a conceptual framework that integrates a broad range of social and ecological factors that define and contextualize the possible future of tropical forest species. A growing body of research demonstrates that spatial and temporal patterns of biodiversity are the dynamic product of interacting historical and contemporary human and ecological processes. These processes vary radically in their relative importance within and among regions, and have effects that may take years to become fully manifest. Interpreting biodiversity research findings is frequently made difficult by constrained study designs, low congruence in species responses to disturbance, shifting baselines and an over-dependence on comparative inferences from a small number of well studied localities. Spatial and temporal heterogeneity in the potential prospects for biodiversity conservation can be explained by regional differences in biotic vulnerability and anthropogenic legacies, an ever-tighter coupling of human-ecological systems and the influence of global environmental change. These differences provide both challenges and opportunities for biodiversity conservation. Building upon our synthesis we outline a simple adaptive-landscape planning framework that can help guide a new research agenda to enhance biodiversity conservation prospects in the human-modified tropics.     

The role of hydrochory in structuring riparian and wetland vegetation

Hydrochory, or the passive dispersal of organisms by water, is an important means of propagule transport, especially for plants. During recent years, knowledge about hydrochory and its ecological consequences has increased considerably and a substantial body of literature has been produced. Here, we review this literature and define the state of the art of the discipline. A substantial proportion of species growing in or near water have propagules (fruits, seeds or vegetative units) able to disperse by water, either floating, submerged in flowing water, or with the help of floating vessels. Hydrochory can enable plants to colonize sites out of reach with other dispersal vectors, but the timing of dispersal and mechanisms of establishment are important for successful establishment. At the population level, hydrochory may increase the effective size and longevity of populations, and control their spatial configuration. Hydrochory is also an important source of species colonizing recruitment‐limited riparian and wetland communities, contributing to maintenance of community species richness. Dispersal by water may even influence community composition in different landscape elements, resulting in landscape‐level patterns. Genetically, hydrochory may reduce spatial aggregation of genetically related individuals, lead to high gene flow among populations, and increase genetic diversity in populations receiving many propagules. Humans have impacted hydrochory in many ways. For example, dams affect hydrochory by reducing peak flows and hence dispersal capacity, altering the timing of dispersal, and by presenting physical barriers to dispersal, with consequences for riverine plant communities. Hydrochory has been inferred to be an important vector for the spread of many invasive species, but there is also the potential for enhancing ecosystem restoration by improving or restoring water dispersal pathways. Climate change may alter the role of hydrochory by modifying the hydrology of water‐bodies as well as conditions for propagule release and plant colonization.     

Dry season habitat use by critically endangered white-shouldered ibis in northern Cambodia

We present the first scientific study of white-shouldered ibis Pseudibis davisoni habitat preferences in dry dipterocarp forest. Foraging sites included seasonal pools, forest understorey grasslands and fallow rice fields, with terrestrial sites used more following rainfall. Habitat and anthropogenic effects in logistic models of foraging site selection were examined by multimodel inference and model averaging. White-shouldered ibis preferred pools with greater cover of short vegetation (<25 cm) and less of the boundary enclosed, and forest sites with greater cover of bare substrate and lower people encounter rate. At forest sites, livestock density was positively related to bare substrate extent and thus may improve suitability for foraging ibis. At pools, livestock removed tall vegetation between the early and late dry season indicating their importance in opening up foraging habitats after wet season growth. However, by the late dry season, pools with greater livestock density had less short vegetation, the habitat favoured by ibis. Conservation strategies for white-shouldered ibis must consider a range of habitats, not just seasonal wetlands, and should incorporate extensive grazing and associated burning practises of local communities. Further understanding of the effects of these practices on vegetation, prey abundance and prey availability are therefore needed for effective conservation of this species. This will also develop our understanding of potentially beneficial anthropogenic influences in tropical environments.     

1896年和1986年黑龙江省几种森林景观的特征变化

通过用地理信息系统软件对 1896和 1986年的黑龙江省的森林分布图中提取的 5种森林景观进行处理和计算得到 :在 90年中 ,云杉 (Picea)、冷杉 (Abies)林、樟子松 (Pinussylvestrisvar.mongolicaLitvin)林和阔叶红松 (PinuskoraieusisSieb .etZucc .)林斑块总面积分别减少 87%、40 %和 84%。北纬 5 1°以北地区阔叶林斑块面积增加 5 0 0 % ,北界向西北扩展约 2 90km。云杉、冷杉林和针阔混交林斑块在 1986年的斑块的分维数小于 1896年的斑块的分维数 ,而樟子松林、阔叶红松林和阔叶林的 1986年斑块分维数都分别大于 1896年的分维数。云杉、冷杉林、樟子松林、阔叶红松林和阔叶林景观破碎化增加。云杉、冷杉林 ,樟子松林和阔叶红松林转化为针阔混交林的比率大于各自保留的比率。     

1940—2002年长江中下游平原乡村景观区域中土地利用覆被及其土壤有机碳储量变化

过去60a来,长江中下游平原的乡村地区发展迅速,引起土地利用覆被及其土壤有机碳储量明显地变化。通过选取区域代表性样方、基于1942年航片和2002年IKONOS影像研究小尺度土地利用覆被变化、土壤取样和收集1965年前土壤有机碳历史数据,用尺度推绎和蒙特卡洛不确定性分析方法,评价了19402002年长江中下游平原人口密集的乡村景观区域中土地利用覆被的面积及其030cm土壤(或底泥)有机碳储量的变化。结果表明:近60a来,在86×103km2的区域中有47%的面积发生土地利用覆被转化,其中耕地转化为非耕地的面积为21%(18×103km2)。土地利用覆被类型转化及其有机碳密度的变化导致该区域土壤有机碳储量的净增加。该区域稻田和闲置水域面积分别减少了21.5%(18.5×103km2)和6.7%(5.7×103km2),导致其土壤(或底泥)有机碳储量分别减少41.8TgC和12.9TgC;而水产养殖、非渗漏表面为主的建筑用地、种植木本作物和种植1年生作物的水浇地面积分别增加了14.2%(12.2×103km2)、7.7%(6.7×103km2)、3.5%(3.0×103km2)和2.0%(1.7×103km2),使其土壤(或底泥)有机碳储量分别增加32.2TgC、22.2TgC、12.2TgC和6.5TgC。近60a来,整个区域030cm土壤有机碳的储量增加了18.2TgC,其净增加的可能性为75%,形成了弱碳汇。这主要是由于区域稻田土壤有机碳密度增加了17%,使区域土壤有机碳储量增加了22.2TgC(其净增加的可能性为92%);而且,稻田转化为种植木本作物和种植1年生作物的水浇地也使区域土壤有机碳储量分别增加了1.3TgC(净增加的可能性为86%)和0.3TgC(净增加的可能性为70%);此外,闲置水域转化为水产养殖也使区域土壤有机碳储量增加1.3TgC(净增加的可能性为77%)。但是,稻田转化为水产养殖和非渗漏表面为主的建筑用地导致区域土壤有机碳储量损失6.3TgC和0.6TgC。因稻田土壤有机碳密度增加及稻田转化类型的土壤有机碳储量变化的影响,使整个区域形成弱碳汇,但如果稻田继续减少的话,很可能变成碳源。通过选取区域代表性样方、研究小尺度土地利用覆被变化、土壤取样和收集土壤历史数据,采用尺度推绎方法,研究揭示了19402002年长江中下游平原人口密集的乡村景观区域中土地利用覆被的面积及其土壤有机碳储量的变化。     

Dracula’s ménagerie: A multispecies occupancy analysis of lynx,wildcat, and wolf in the Romanian Carpathians

1. The recovery of terrestrial carnivores in Europe is a conservation success story. Initiatives focused on restoring top predators require information on how resident species may interact with the re‐introduced species as their interactions have the potential to alter food webs, yet such data are scarce for Europe.
2. In this study, we assessed patterns of occupancy and interactions between three carnivore species in the Romanian Carpathians. Romania houses one of the few intact carnivore guilds in Europe, making it an ideal system to assess intraguild interactions and serve as a guide for reintroductions elsewhere.
3. We used camera trap data from two seasons in Transylvanian forests to assess occupancy and co‐occurrence of carnivores using multispecies occupancy models.
4. Mean occupancy in the study area was highest for lynx (Ψ_winter = 0.76 95% CI: 0.42–0.92; Ψ_autumn = 0.71 CI: 0.38–0.84) and wolf (Ψ_winter = 0.60 CI: 0.34–0.78; Ψ_autumn = 0.81 CI: 0.25–0.95) and lowest for wildcat (Ψ_winter = 0.40 CI: 0.19–0.63; Ψ_autumn = 0.52 CI: 0.17–0.78)
5. We found that marginal occupancy predictors for carnivores varied between seasons. We also found differences in predictors of co‐occurrence between seasons for both lynx‐wolf and wildcat‐wolf co‐occurrence. For both seasons, we found that conditional occupancy probabilities of all three species were higher when another species was present.
6. Our results indicate that while there are seasonal differences in predictors of occupancy and co‐occurrence of the three species, co‐occurrence in our study area is high.
7. Terrestrial carnivore recovery efforts are ongoing worldwide. Insights into interspecific relations between carnivore species are critical when considering the depauperate communities they are introduced in. Our work showcases that apex carnivore coexistence is possible, but dependent on protection afforded to forest habitats and their prey base.

     

芦芽山自然保护区旅游开发与植被环境关系——植被景观的类型及其排序

正确识别旅游活动作用下植被景观的类型及其分布格局,是景区管理者实施生态管理的现实课题。以芦芽山自然保护区为例,利用双向指示种分析（Two．Way Indicator Species Analysis,TWINSPAN）和除趋势对应分析（Detrended Correspondence Analysis,DCA）对此问题进行了研究。结果表明：（1）TWINSPAN将所有样地划分为5个不同等级的植被景观类型区,其结果比较客观地反映出旅游开发与植被景观间的生态关系,指示因子也充分地反映了植被区的人为环境和景观特征。与利用旅游影响系数进行的分类相比,TWINSPAN的结果更为科学合理,明显优于单纯依据一个因子划分的结果。（2）DCA第1轴从左到右旅游影响系数和敏感水平越来越小,信息指数越来越大。DCA第3轴从下而上旅游剔除程度逐渐减小。DCA结果能够识别植被景观类型在空间上分布的规律性,但是这种规律性需要根据生态学知识去加以分析和总结,直观性不强。（3）TWINSPAN结果与DCA结果基本一致。具有良好的可比性。