·荒漠草地植物多样性对草食动物采食的响应机制

草食动物采食对草地植物多样性和生态系统功能的影响机制是放牧生态学研究的核心问题。该研究以内蒙古锡林郭勒盟苏尼特右旗荒漠草原的长期放牧控制实验为平台, 从既有草地植物多样性和动物偏食性两个层面系统地研究了荒漠草地植物多样性对草食动物采食的响应机制。结果显示: 1)荒漠草地植物对草食动物采食呈现4种响应模式: 放牧“隐没种”、放牧“敏感种”、放牧“无感种”、“绝对优势种”; 2)在群落尺度上, 物种多样性指数随放牧强度增加而减少, 与不放牧小区相比, 重度放牧(HG)与适度放牧(MG)小区植物多样性均下降, 且这一规律同样适用于功能群多样性, 灌木半灌木这一功能群内物种多样性对放牧干扰较敏感; 3)在草地既有植物的基础上, 以不放牧小区为参考系, 草食动物对植物功能群偏食性的排序为: 一二年生草本(AB) >多年生杂类草(PF) >灌木半灌木(SS) >多年生禾草(PG), 且偏食性物种主要分布于AB和PF中; 4)植物多样性与动物偏食性基本呈显著负相关关系(p < 0.05)。     

克隆植物种群生态学研究透视

克隆植物种群日益受到关注和重视 ,克隆植物种群生态学的研究正在广泛深入地开展。探讨了克隆植物种群研究的最新进展 ,介绍了有关理论、方法和取得的成果 ,并对克隆植物种群在现代生态学中的地位与作用进行了评述     

植物养分捕获的菌根塑性——外生菌根的塑性

植物根资源捕获塑性是地下生态学研究的重点之一, 在过去二三十年间有长足的进步。菌根塑性是根资源捕获塑性的重要方面, 但由于研究手段的限制, 目前仅有概念上的探讨。缺乏菌根塑性的根塑性研究至少是不全面的。菌根生物学的迅速发展, 尤其是分子生物学手段的介入, 使对菌根塑性进行深入研究成为可能。该文对外生菌根塑性进行讨论, 在简要介绍了外生菌根的生物学基本知识后, 着重讨论了外生菌根形态塑性和生理塑性的定义与内涵。通过文献综述, 分析讨论了外生菌根塑性的研究现状: 很少有研究聚焦在菌根塑性本身, 现有的材料多为其他研究的隐示或研究结果的引申, 并多在形态塑性方面。外生菌根的生理塑性未见有直接的实验数据。该文还对外生菌根研究中发展的、可用于菌根塑性研究的方法进行了综述。由于外生菌根塑性的复杂性, 对菌根塑性的研究会较植物根本身塑性的研究复杂得多, 问题也会相对复杂, 比如植物和外生菌根菌之间的营养需求关系、植物外生菌根塑性的生态意义、实验方法的缺陷等等。对今后外生菌根塑性研究的方向进行了探讨。     

How functional is functional? Ecological groupings in terrestrial animal ecology: towards an animal functional type approach

Understanding mechanisms to predict changes in plant and animal communities is a key challenge in ecology. The need to transfer knowledge gained from single species to a more generalized approach has led to the development of categorization systems where species’ similarities in life strategies and traits are classified into ecological groups (EGs) like functional groups/types or guilds. While approaches in plant ecology undergo a steady improvement and refinement of methodologies, progression in animal ecology is lagging behind. With this review, we aim to initiate a further development of functional classification systems in animal ecology, comparable to recent developments in plant ecology. We here (i) give an overview of terms and definitions of EGs in animal ecology, (ii) discuss existing classification systems, methods and application areas of EGs (focusing on terrestrial vertebrates), and (iii) provide a “roadmap towards an animal functional type approach” for improving the application of EGs and classifications in animal ecology. We found that an animal functional type approach requires: (i) the identification of core traits describing species’ dependency on their habitat and life history traits, (ii) an optimization of trait selection by clustering traits into hierarchies, (iii) the assessment of “soft traits” as substitute for hardly measurable traits, e.g. body size for dispersal ability, and (iv) testing of delineated groups for validation including experiments.     

Animal movements in fire‐prone landscapes

Movement is a trait of fundamental importance in ecosystems subject to frequent disturbances, such as fire‐prone ecosystems. Despite this, the role of movement in facilitating responses to fire has received little attention. Herein, we consider how animal movement interacts with fire history to shape species distributions. We consider how fire affects movement between habitat patches of differing fire histories that occur across a range of spatial and temporal scales, from daily foraging bouts to infrequent dispersal events, and annual migrations. We review animal movements in response to the immediate and abrupt impacts of fire, and the longer‐term successional changes that fires set in train. We discuss how the novel threats of altered fire regimes, landscape fragmentation, and invasive species result in suboptimal movements that drive populations downwards. We then outline the types of data needed to study animal movements in relation to fire and novel threats, to hasten the integration of movement ecology and fire ecology. We conclude by outlining a research agenda for the integration of movement ecology and fire ecology by identifying key research questions that emerge from our synthesis of animal movements in fire‐prone ecosystems.     

动物传播者对植物更新的促进与限制

在动物 植物的关系网络中,传播者对植物更新具有促进与限制两方面作用.本文从种群尺度总结了传播者取食、空间利用等行为对植物更新的影响;从群落尺度分析了多种传播者传播有效性对植物更新的促进与限制.传播者对食物的处理方式决定了种子的命运,且具有明显的种间差异;植物在传播者食谱中的地位亦决定其更新的成败,成为动物偏好的食物可助其摆脱森林破碎化等不利事件的影响.动物的空间行为可导致种子命运发生改变.传播者移动距离能否逃逸同种成树对种子的距离限制,影响种子的更新命运;动物偏好的适宜生境与适于植物萌发生境的空间一致性程度影响传播者传播的成效.有效传播者的非冗余性促使种子传播网络更稳定,利于植物更新;无效传播直接限制植物更新,但为其他植物定殖提供了可用空间.今后应将传播者行为融入植物种群更新研究,而从生态系统服务角度揭示传播者在植被恢复的作用应是未来恢复生态学研究的重点.     

Seasonal patterns in the foraging ecology of the harvester ant Pogonomyrmex naegelii (Formicidae, Myrmicinae) in a Neotropical savanna: daily rhythms, shifts in granivory and carnivory, and home range

The temporal dynamics of foraging, diet, and use of space is essential to understand the ecology of harvester ants. Here, we present an account of the foraging ecology of Pogonomyrmex naegelii in Brazilian cerrado savanna. Nests occur on bare ground and contain 166?C580 workers (N?=?3 colonies). Colony activity is unimodal year-round and peaks around the middle of the day. Foragers leave the nest independently and individually search for food in all directions. Ants ventured up to 15?m from nests, with most foraging occurring within 2?m of nests. Colonies tended to have larger home ranges in the dry/cold (April?CSeptember) than in the wet/warm season (October?CMarch). P. naegelii has a generalist and season-dependent diet comprised of many seed species and arthropod prey, and pieces of plant and animal matter. Foragers collected seeds from 34 plant species, predominantly grasses (genera Gymnopogon, Axonopus, Aristida). Over 6,700 seeds can be stored in nest granaries. Ants and termites were the main animal prey retrieved by P. naegelii. The proportion of seeds and arthropods foraged by P. naegelii changes year-round: in the dry/cold season, the diet is predominantly granivorous, whereas in the wet/warm season, seeds and arthropods are retrieved in more balanced proportions. Although food availability was not assessed, year-round diet of P. naegelii matches the pattern of seasonal abundance of grass seeds and arthropod prey in cerrado. Data on harvester ants come mostly from arid habitats; this study is a first assessment of the ecology of a Neotropical Pogonomyrmex from a moderately moist savanna environment.     

Complementarity effects through dietary mixing enhance the performance of a generalist insect herbivore

The ontogenetic niche concept predicts that resource use depends on an organism’s developmental stage. This concept has been investigated primarily in animals that show differing resource use strategies as juveniles and as adults, such as amphibians. We studied resource use and performance in the grasshopper Chorthippus parallelus (Orthoptera, Acrididae) provided with food plant mixtures of either one, three or eight plant species throughout their development. C. parallelus survival and fecundity was highest in the food plant mixture with eight plant species and lowest in the treatments where only one single plant species was offered as food. C. parallelus’ consumption throughout its ontogeny depended on sex, and feeding on different plant species was dependent on a grasshopper’s developmental stage. To depict grasshopper foraging in food plant mixtures compared to foraging on single plant species, we introduce the term “relative forage total” (RFT) based on an approach used in biodiversity research by Loreau and Hector (Nature 413:548–274, 2001). RFT of grasshoppers in food plant mixtures was always higher than what would have been expected from foraging in monocultures. The increase in food consumption was due to an overall increase in feeding on plant species in mixtures compared to consumption of the same species offered as a single diet. Thus we argue that grasshopper foraging exhibits complementarity effects. Our results reinforce the necessity to consider development-related changes in insect herbivore feeding. Thorough information on the feeding ontogeny of insect herbivores could not only elucidate their nutritional ecology but also help to shed light on their functional role in plant communities. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Foraging speed and precision of arbuscular mycorrhizal fungi under field conditions: An experimental approach

To better understand the ecology of arbuscular mycorrhizal (AM) symbiosis, we need to measure functional traits of individual fungal virtual taxa under field conditions. The efficiency of AM fungi in locating nutrient‐rich patches in soil space is one of their central traits in this symbiotic relationship. We used plots of a long‐term field experiment in grassland with manipulated functional group composition of host plant community to establish ingrowth patches with substrate free of roots and fungi and with varying nutrient availability. Comparison of the original AM fungal community before patch creation with that present 9 weeks after patch establishment enabled us to estimate relative hyphal foraging speed for 41 fungal taxa, and a comparison of the fungal community in neighbouring patches differing in nutrient availability provided estimates of hyphal foraging precision for 22 taxa. Members of two dominant fungal families, Glomeraceae and Claroideoglomeraceae, differed in their foraging speed and precision. Glomeraceae taxa responded more slowly, but with a higher focus on enriched patches. We further demonstrated the usefulness of the obtained fungal functional traits by testing the differences between grass and dicotyledonous plant hosts using a data set obtained in another experiment at the same plots. Grass species hosted AM fungal communities with higher foraging speed, but lower foraging precision than the dicotyledonous species. Our study results support the use of field experiments for measuring comparative characteristics of AM fungi, which are highly elusive (or misrepresented) under controlled conditions.     

Foraging for animal prey by outdoor groups of Geoffroy’s marmosets (Callithrix geoffroyi)

I studied animal prey foraging by three outdoor groups of Geoffroy’s marmosets, Callithrix geoffroyi, over the course of two summers (June–August 1994; August–September, 1995. Marmosets are highly motivated to forage for animal prey, as demonstrated by the amount of time spent foraging for insects and small vertebrates even in the presence of provisioned, high-quality food. Like their wild congeners, the marmosets engaged in prolonged visual searches of selected areas while slowly locomoting. They seldom used their hands to manipulate substrates. The marmosets were startled proportionately more often while foraging for animal prey than would be predicted by their overall time budgets, and they regularly, if briefly, interrupted their search/locomote pattern with sweeping scans of the surroundings that may contribute to a vigilance function. While carrying infants, they almost never foraged. These results are consistent with the notion that marmosets may be particularly vulnerable to predation while searching for animal prey. Most of the data on marmoset and tamarin feeding ecology have focused on fruits and gums. My data underscore the need to understand better the role of animal prey in the behavioral ecology of callitrichids.     

Frugivores and cheap fruits make fruiting fruitful

Animal seed dispersal provides an important ecosystem service by strongly benefiting plant communities. There are several theoretical studies on the ecology of plant–animal seed–disperser interactions, but few studies have explored the evolution of this mutualism. Moreover, these studies ignore plant life history and frugivore foraging behaviour. Thus, it remains an open question what the conditions for the diversification of fruit traits are, in spite of the multitude of empirical studies on fruit trait diversity. Here, we study the evolution of fruit traits using a spatially explicit individual‐based model, which considers the costs associated with adaptations inducing dispersal by frugivory, as well as frugivore foraging behaviour and abundance. Our model predicts that these costs are the main determinants of the evolution of fruit traits and that when the costs are not very high, the evolution of larger fruit traits (e.g. fleshy/colourful fruits) is controlled by the choosiness and response thresholds of the frugivores as well as their numerical abundance.     

Using stable isotope biogeochemistry to study marine mammal ecology

Stable isotope analysis (SIA) has emerged as a common tool in ecology and has proven especially useful in the study of animal diet, habitat use, movement, and physiology. SIA has been vigorously applied to the study of marine mammals, because most species live in habitats or undergo large migrations/movements that make them difficult to observe. Our review supplies a complete list of published SIA contributions to marine mammal science and highlights informative case examples in four general research areas: (1) physiology and fractionation, (2) foraging ecology and habitat use, (3) ecotoxicology, and (4) historic ecology and paleoecology. We also provide a condensed background of isotopic nomenclature, highlight several physiological considerations important for accurate interpretation of isotopic data, and identify research areas ripe for future growth. Because it is impossible to conduct controlled laboratory experiments on most marine mammal species, future studies in marine mammal ecology must draw on isotopic data collected from other organisms and be cognizant of key assumptions often made in the application of SIA to the study of animal ecology. The review is designed to be accessible to all audiences, from students unfamiliar with SIA to those who have utilized it in published studies.     

A sense of scale: Foraging cetaceans' use of scale‐dependent multimodal sensory systems

Research on cetacean foraging ecology is central to our understanding of their spatial and behavioral ecology. Yet, functional mechanisms by which cetaceans detect prey across different scales remain unclear. Here, I postulate that cetaceans utilize a scale‐dependent, multimodal sensory system to assess and increase prey encounters. I review the literature on cetacean sensory systems related to foraging ecology, and hypothesize the effective scales of each sensory modality to inform foraging opportunities. Next, I build two “scale‐of‐senses” schematics for the general groups of dolphins and baleen whales. These schematics illustrate the hypothetical interchange of sensory modalities used to locate and discriminate prey at spatial scales ranging from 0 m to 1,000 km: (1) vision, (2) audition (sound production and sound reception), (3) chemoreception, (4) magnetoreception, and somatosensory perception of (5) prey, or (6) oceanographic stimuli. The schematics illustrate how a cetacean may integrate sensory modalities to form an adaptive foraging landscape as a function of distance to prey. The scale‐of‐senses schematic is flexible, allowing for case‐specific application and enhancement with improved cetacean sensory data. The framework serves to improve our understanding of functional cetacean foraging ecology, and to develop new hypotheses, methods, and results regarding how cetaceans forage at multiple scales.     

植物化学防卫与植食性哺乳动物的适应对策

植物化学防卫与植食性哺乳动物的适应是动物—植物系统协同进化研究的重要内容。植物次生化合物可降低动物的食物摄入量及消化率、蛋白质可利用率。某些次生化合物还影响植食性哺乳动物的正常繁殖活动。单宁是动物的重要觅食阻遏剂之一。动物在学习食物选择的过程中,通过认知过程和感知过程处理食物信息,选择食物项目。幼体在胚胎期和哺乳期能从母体获得食物信息,或向有觅食经验的同胞伙伴学习处理食物的经验。动物亦可通过形成络和物,改变体内环境,通过微生物降解、氧化还原、基础代谢率等降低生理对策,以降低植物次生化和物的影响。     

Top-down effects of foraging decisions on local,landscape and regional biodiversity of resources (DivGUD)

Foraging by consumers acts as a biotic filtering mechanism for biodiversity at the trophic level of resources. Variation in foraging behaviour has cascading effects on abundance, diversity, and functional trait composition of the community of resource species. Here we propose diversity at giving-up density (DivGUD), i.e. when foragers quit exploiting a patch, as a novel concept and simple measure quantifying cascading effects at multiple spatial scales. In experimental landscapes with an assemblage of plant seeds, patch residency of wild rodents decreased local α-DivGUD (via elevated mortality of species with large seeds) and regional γ-DivGUD, while dissimilarity among patches in a landscape (ß-DivGUD) increased. By linking theories of adaptive foraging behaviour with community ecology, DivGUD allows to investigate cascading indirect predation effects, e.g. the ecology-of-fear framework, feedbacks between functional trait composition of resource species and consumer communities, and effects of inter-individual differences among foragers on the biodiversity of resource communities.     

植物对植食性哺乳动物的化学防卫

综述植物次生合物防卫植食性哺乳动物食的研究进展,植物组织的次生化合物主要为酚类、萜类及含N类化合物,植物对动物觅食的化学防卫对策以次生化合物的各类而有差异,次生化合物通过对动物的食物摄入、消化、代谢,以及敏殖活动的效应,以抵御动物的觅食。将植物化学防卫与动物适应对策相结合,探讨动物－植物协同进化模式,是该研究领域的主要发展趋势。     

Disturbances by desert rodents are more strongly associated with spatial changes in soil texture than woody encroachment

Background and Aims

Soil texture is an important determinant of ecosystem structure and productivity in drylands, and may influence animal foraging and, indirectly, plant community composition.

Methods

We measured the density and composition of surface disturbances (foraging pits) of small, soil-foraging desert vertebrates in shrubland and grasslands, both with coarse- and fine-textured soils. We predicted that the density and functional significance of disturbances would be related more to differences in texture than shrub encroachment.

Results

Soil texture had a stronger influence on animal foraging sites than shrub encroachment. There were more disturbances, greater richness and abundance of trapped seed, and greater richness of germinating plants on coarse- than fine-textured soils. Pits in coarse soils trapped 50 % more litter than those in finer soils. Apart from slightly more soil removal and greater litter capture in shrubland pits, there were no effects of encroachment.

Conclusions

Although the process of woody encroachment has been shown to have marked effects on some ecosystem properties, it is likely to have a more subordinate effect on surface disturbances and therefore their effects on desert plant communities than soil texture. Our results highlight the importance of animal activity in shaping desert plant communities, and potentially, in maintaining or reinforcing shrub dominant processes.     

Clonal performance of Scirpus yagara in multiple levels of substrate heterogeneity and submergence

荆三棱在多等级基质异质性与水淹处理下的克隆表现 环境异质性可以影响克隆水生植物的表现。鲜有研究者关注两个层次的环境异质性并将其融入 对克隆植物生态学的研究中。本研究的目的是: (1)检验不同基质异质性与水淹处理是否对植物表现产生相 似效应，(2)探索克隆植物的觅食行为。本研究将荆三棱(Scirpus yagara)置于不同基质异质性与水淹处理之中。基质处理包括1个均质性基质处理(湖泥与沙等体积混合)与3个异质性基质处理(湖泥斑块与沙斑块交错构建的两斑块、四斑块与八斑块基质)。水淹处理包括：0、10和30 cm。本实验测量了克隆分株数、克隆代数、叶数、球茎数、克隆分株高度、茎长、根状茎长、克隆半径、间隔子长、间隔子厚度、总生物量、球茎生物量与单个球茎生物量等性状数据。研究结果表明，水位上升导致克隆分株数、克隆代数、叶数和球茎数显著减少，同时基质异质性造成间隔子长度与间隔子厚度的显著变化。水位与基质异质性两因子对克隆分株数、叶数和间隔子长度产生了显著的交互效应。在两斑块基质与四斑块基质中，荆三棱对湖泥斑块表现出显著的觅食行为，更多的构件被放置于湖泥斑块中。尤其在两斑块基质中，所有的构件被放置于湖泥斑块中。在八斑块基质中，荆三棱表现出双向觅食，这导致构件在不同斑块中的均匀放置。研究结果表明，荆三棱的觅食行为与斑块大小具有相关性。     

The prominence of and biases in biodiversity and ecosystem functioning research

The sub-discipline of biodiversity and ecosystem functioning (BEF) has emerged as a central topic in contemporary ecological research. However, to date no study has evaluated the prominence and publication biases in BEF research. Herein we report the results of a careful quantitative assessment of BEF research published in five core general ecology journals from 1990 to 2007 to determine the position of BEF research within ecology, identify patterns of research effort within BEF research, and discuss their probable proximal and historical causes. The relative importance of BEF publications increased exponentially during the period analyzed and was significantly greater than the average growth of ecological literature, affirming the prominence of BEF as a current paradigm in ecology. However, BEF research exhibited a strong bias toward experimental studies on terrestrial plant communities, with significantly lower effort devoted to the functional aspects of biodiversity in aquatic systems, multiple trophic level systems, and animal or microbial communities. Such trends may be explained by a combination of methodological adequacy and historic epistemological differences in ecological thinking. We suggest that BEF researchers should direct more effort toward the study of aquatic systems and animal communities, emphasize long-term and trophically complex experiments, such as those with multi-trophic microbial communities, employ larger-scale field observational studies and increase the use of integrative and theoretical studies. Many technical and analytical methodologies that are already employed in ecological research, such as stable isotopes, paleobiology, remote sensing, and model selection criteria, can facilitate these aims. Overcoming the above-mentioned shortcomings of current BEF research will greatly improve our ability to predict how biodiversity loss will affect ecosystem processes and services in natural ecosystems.     

Colour learning when foraging for nectar and pollen: bees learn two colours at once

Bees are model organisms for the study of learning and memory, yet nearly all such research to date has used a single reward, nectar. Many bees collect both nectar (carbohydrates) and pollen (protein) on a single foraging bout, sometimes from different plant species. We tested whether individual bumblebees could learn colour associations with nectar and pollen rewards simultaneously in a foraging scenario where one floral type offered only nectar and the other only pollen. We found that bees readily learned multiple reward–colour associations, and when presented with novel floral targets generalized to colours similar to those trained for each reward type. These results expand the ecological significance of work on bee learning and raise new questions regarding the cognitive ecology of pollination.