基于GIS的稻田蜘蛛混合种群发生分析

在地理信息系统的支持下 ,对中国稻区 117个样点蜘蛛物种数与个体数进行空间插值 ,获得稻田蜘蛛混合种群数量专题地图和个体数量发生专题地图 .根据所得专题地图 ,分析了不同水稻种植区蜘蛛种群发生以及不同稻区的生态特征 .研究结果如下 :在北纬 35 .5°以南的水稻种植区域 ,蜘蛛种群与个体发生量较高 ,种群一般在 13种以上 ,个体数一般在每 10 0丛禾 10 0头以上 ;在北纬 35 .5°以北的水稻种植区域种群一般在 11种以下 ,个体数一般在每 10 0丛禾 47头以下 ;在北纬 35 .5°以南的水稻种植区域的年降雨量、年无霜期和 7月平均温度要高于在北纬 35 .5°以北的水稻种植区域 .在北纬 35 .5°以南的水稻种植区域的年日照时数要低于在北纬 35 .5°以北的水稻种植区域 .     

Mechanistic niche modelling: combining physiological and spatial data to predict species' ranges

Species distribution models (SDMs) use spatial environmental data to make inferences on species' range limits and habitat suitability. Conceptually, these models aim to determine and map components of a species' ecological niche through space and time, and they have become important tools in pure and applied ecology and evolutionary biology. Most approaches are correlative in that they statistically link spatial data to species distribution records. An alternative strategy is to explicitly incorporate the mechanistic links between the functional traits of organisms and their environments into SDMs. Here, we review how the principles of biophysical ecology can be used to link spatial data to the physiological responses and constraints of organisms. This provides a mechanistic view of the fundamental niche which can then be mapped to the landscape to infer range constraints. We show how physiologically based SDMs can be developed for different organisms in different environmental contexts. Mechanistic SDMs have different strengths and weaknesses to correlative approaches, and there are many exciting and unexplored prospects for integrating the two approaches. As physiological knowledge becomes better integrated into SDMs, we will make more robust predictions of range shifts in novel or non-equilibrium contexts such as invasions, translocations, climate change and evolutionary shifts.     

Niche-tracking migrants and niche-switching residents: evolution of climatic niches in New World warblers (Parulidae)

Differences in life-history traits between tropical and temperate lineages are often attributed to differences in their climatic niche dynamics. For example, the more frequent appearance of migratory behaviour in temperate-breeding species than in species originally breeding in the tropics is believed to have resulted partly from tropical climatic stability and niche conservatism constraining tropical species from shifting their ranges. However, little is known about the patterns and processes underlying climatic niche evolution in migrant and resident animals. We evaluated the evolution of overlap in climatic niches between seasons and its relationship to migratory behaviour in the Parulidae, a family of New World passerine birds. We used ordination methods to measure seasonal niche overlap and niche breadth of 54 resident and 49 migrant species and used phylogenetic comparative methods to assess patterns of climatic niche evolution. We found that despite travelling thousands of kilometres, migrants tracked climatic conditions across the year to a greater extent than tropical residents. Migrant species had wider niches than resident species, although residents as a group occupied a wider climatic space and niches of migrants and residents overlapped extensively. Neither breeding latitude nor migratory distance explained variation among species in climatic niche overlap between seasons. Our findings support the notion that tropical species have narrower niches than temperate-breeders, but does not necessarily constrain their ability to shift or expand their geographical ranges and become migratory. Overall, the tropics may have been historically less likely to experience the suite of components that generate strong selection pressures for the evolution of migratory behaviour.     

应用GIS技术进行野生动物生境研究概况及展望

1　 GIS的特性及对野生动物生境研究产生的影响近年来 ,生物多样性的研究和保护已在多层次、多水平上展开 [2 7] ,其中对野生动物生境的保护和研究是非常重要的一方面。生境 ( habitat)一词首先由美国的 Grinnel于 1 91 7年提出 ,指的是生物的居住场所 ,即生物个体、种群或群落能在其中完成生命过程的空间 [11]。自然界的生物都有它特定的生活环境 ,都有各自要求的适宜的环境条件。由于生物种类繁多 ,生物和环境、生物和生物之间的关系错综复杂 ,因此 ,野生动物生境的保护涉及到许多与时间动态及空间格局相关的问题。传统动物生态学和动物…     

The biogeography of prediction error: why does the introduced range of the fire ant over‐predict its native range?

Aim The use of species distribution models (SDMs) to predict biological invasions is a rapidly developing area of ecology. However, most studies investigating SDMs typically ignore prediction errors and instead focus on regions where native distributions correctly predict invaded ranges. We investigated the ecological significance of prediction errors using reciprocal comparisons between the predicted invaded and native range of the red imported fire ant (Solenopsis invicta) (hereafter called the fire ant). We questioned whether fire ants occupy similar environments in their native and introduced range, how the environments that fire ants occupy in their introduced range changed through time relative to their native range, and where fire ant propagules are likely to have originated. Location We developed models for South America and the conterminous United States (US) of America. Methods We developed models using the Genetic Algorithm for Rule‐set Prediction (GARP) and 12 environmental layers. Occurrence data from the native range in South America were used to predict the introduced range in the US and vice versa. Further, time‐series data recording the invasion of fire ants in the US were used to predict the native range. Results Native range occurrences under‐predicted the invasive potential of fire ants, whereas occurrence data from the US over‐predicted the southern boundary of the native range. Secondly, introduced fire ants initially established in environments similar to those in their native range, but subsequently invaded harsher environments. Time‐series data suggest that fire ant propagules originated near the southern limit of their native range. Conclusions Our findings suggest that fire ants from a peripheral native population established in an environment similar to their native environment, and then ultimately expanded into environments in which they are not found in their native range. We argue that reciprocal comparisons between predicted native and invaded ranges will facilitate a better understanding of the biogeography of invasive and native species and of the role of SDMs in predicting future distributions.     

Range size and environmental calcium requirements of British freshwater gastropods

Calcium is an essential requirement for the successful growth and development of gastropod molluscs. Data for British freshwater gastropods were used to examine the relationship between environmental calcium requirements and British and European range sizes. At both spatial scales calciphile species, which require a high level of environmental calcium, had significantly smaller range sizes than species able to exploit a wide range of environmental calcium levels. However, at least in Britain, range size may also be influenced by the availability of suitable habitat. British and European range sizes were significantly correlated. This study provides evidence for niche‐based explanations of range size variation, and suggests that both niche breadth and niche availability are important in determining range size.     

HOW IS THE RATE OF CLIMATIC‐NICHE EVOLUTION RELATED TO CLIMATIC‐NICHE BREADTH?

The rate of climatic‐niche evolution is important to many research areas in ecology, evolution, and conservation biology, including responses of species to global climate change, spread of invasive species, speciation, biogeography, and patterns of species richness. Previous studies have implied that clades with higher rates of climatic‐niche evolution among species should have species with narrower niche breadths, but there is also evidence suggesting the opposite pattern. However, the relationships between rate and breadth have not been explicitly analyzed. Here, we examine the relationships between the rate of climatic‐niche evolution and climatic‐niche breadth using phylogenetic and climatic data for 250 species in the salamander family Plethodontidae, a group showing considerable variation in both rates of climatic‐niche evolution and climatic‐niche breadths. Contrary to some expectations, we find no general relationship between climatic‐niche breadth and the rate of climatic‐niche evolution. Climatic‐niche breadths for some ecologically important climatic variables considered separately (temperature seasonality and annual precipitation) do show significant relationships with the rate of climatic‐niche evolution, but rates are faster in clades in which species have broader (not narrower) niche breadths. In summary, our results show that narrower niche breadths are not necessarily associated with faster rates of niche evolution.     

Demographic constraints in evolution: Towards unifying the evolutionary theories of senescence and niche conservatism

Summary I suggest that there may be a fundamental conceptual unity between two seemingly disparate phenomena: (1) senescence (the progressive deterioration in physiological function and, thus, individual fitness with age) and (2) niche conservatism (the observation that species often seem rather fixed over evolutionary time in their basic niche properties). I argue that both phenomena arise from demographic asymmetries. The evolutionary theory of ageing rests on the observation that the force of selection declines with age, reflecting the basic demographic facts that in persistent populations there are always fewer individuals in old than in young age classes and these individuals tend to have lower reproductive value. A similar demographic asymmetry arises when populations inhabit environments with source habitats (i.e. where conditions are within the species' niche) and sink habitats (where conditions lie outside the niche): there tend to be more individuals in sources than in sinks and individuals in sources have relatively higher reproductive values. These demographic asymmetries should often imply that the force of selection is greater in sources than in sinks, leading automatically towards niche conservatism. I suggest that niche evolution is most likely in circumstances where these demographic asymmetries in space weaken or reverse.