Journal of Animal Ecology

The manner in which animals respond to risk is crucial in understanding species coexistence. Here the authors show that avoidance of more dominant predators by cheetahs in northern Botswana is reactive rather than predictive – a strategy that could be key in enabling competing species to coexist in an ecosystem where risks are widespread and recurrent.

This study shows, for the first time, that the effects hosts and parasites exert on each other (e.g. hosts providing resources to parasites and parasites exploiting the resources of hosts) are driven by temporally-persistent species. However, effects of some species vary greatly with time while those of others are temporally-stable.

This study provides the first evidence of Allee effects in ants. The results demonstrate the differential effect of queens and workers on survival and productivity. A potential positive feedback between worker and queen abundance may have contributed to the evolution of large colony sizes.

Using Dynamic Energy Budget theory, the authors consider universal constraints on the storage and use of assimilated nutrients and derive an equation for the body-size scaling of metabolic rate without relying on optimisation arguments. The mechanism offers an explanation for differences between the intra- and inter-specific scaling of biological rates with mass.

Here the authors document clinal variation in body size, but only modest variation in thermal tolerances and metabolic rates along the elevation gradient. These results show that quantifying energy balances and allocation offers a viable approach for predicting how populations will respond to climate change.

This paper provides rare empirical tests of competing models of patch-departure decisions in natural and field-experimental foraging conditions. It shows that foragers' patch-departure decisions may depend on the characteristics of the environment, and that in some environments simpler models can provide a good description of this behaviour. Photo by Harry Marshall/ZSL Tsaobis Baboon Project.

Using a unique interconnected experimental system, the authors investigate the effect of sex ratio on dispersal in a butterfly. Controlling individual and population characteristics with this approach allows specific determination of the effect of varying sex ratio on the dispersal response, which is a breakthrough in knowledge of the dispersal process that would have been extremely difficult to achieve in nature.

This is the first comprehensive review of how to analyse community dynamics in space and time using specific species abundance models. The authors argue for a parametric approach in studies of community structure and organization, and assume an underlying lognormal form of the species abundance distribution.

This paper reports the results of a biodiversity-ecosystem functioning experiment that for the first time manipulates diversity simultaneously within and across trophic levels. The key finding is that ecosystem functioning increases with food web complexity, suggesting that the consequences of biodiversity loss could be more severe than inferred from previous experiments.

This paper compares and contrasts resource utilization and resource selection functions, showing that RUFs can actually out perform traditional RSFs in certain cases. This is the first paper to formally attempt to reconcile these two approaches for understanding animal resource selection.

In this contribution to the Special Feature on ‘Metabolism as a Currency and Constraint in Ecology’, the authors show that many organisms display a power-law dependence of metabolic rate with population density that is likely caused by density-dependent foraging rates. These results open a new window into the relative performance of organisms with implications for scaling up energetic fluxes and understanding rare or invasive species.

This paper presents a meta-analysis of 148 food supplementation experiments carried out with small mammals. The analyses support the view that animal population density is determined by both bottom-up and top-down forces. They also suggest the possibility that food supplementation experiments might unintentionally create ecological traps

This is one of the few studies testing Bergmann's rule in a tropical taxon, demonstrating two patterns of size variation in a canid species: populations south of the Equator follow Bergmann's rule while Northern populations reflect the opposite. The study implicates historical factors, local adaptation and genetic drift in influencing this deviation from Bergmann's rule.

This study uses structural equation modeling to realistically model habitat fragmentation as a hierarchical process using habitat data collected at an almost yearly frequency and a long-term dataset of biological data from an area-sensitive species. This increases our understanding of the effects of habitat fragmentation on reproductive success.

This study shows that space use and habitat selection by animals changes drastically as a function of habitat availability, even when animals use simple and consistent movement rules to explore and exploit space. The utility of a variety of existing and new methods to explicitly estimate the influence of habitat availability is demonstrated, with potential for improved inference and prediction.

This study shows that regardless of the low concentrations at which nitrogen and amino acids are present in floral nectar, their presence affects bats' food selection by interfering with the bats' ability to detect differences in sugar concentrations, and by offering particular flavours that can be perceived and selected by nectarivorous bats.

This paper, a model of phytoplankton growth and competition for nutrients, provides the first competition-based explanation for why body sizes of ectotherms are smaller in warmer environments and appear to be shrinking with climate change. This work is an important contribution towards predicting possible future impacts of climate change on ecological systems.

Here the authors document digestive flexibility in a high latitude fish that capitalizes on annual pulsed subsidies. This is one of the first examples of phenotype flexibility in wild fish, and one of the first studies to consider physiological adaptation to resource pulses.

Understanding the relationship between landscape-scale phenological events and migratory patterns of wide-ranging species is an important aspect of quantifying and predicting the effects of global climate change. The results from these analyses can be used to explain recently published declines in polar bear body condition, reproduction, and population numbers.

This paper focuses on the effects of habitat fragmentation on bird functional diversity – a question that has remained relatively poorly understood, despite its importance to ecological functioning in fragmented habitats. The findings, which extend the classical theory of island biogeography, support the need for these effects to be explicitly considered in reserve design.

The results of this study suggest a new potential mechanism – that increasing predator size diversity enhances the strength of top-down control on prey through diet niche partitioning. This mechanism extends the current knowledge on top-down control in aquatic ecosystems, and may have important management implications.

Migration among patches in a metapopulation may be limited by migrants or by patch quality. In an intensively studied Daphnia metapopulation, the authors reveal that patch quality is a strongly limiting factor. Actual migration rates are 3–5 times higher than previously thought, making the entire metapopulation much more dynamic than previous studies assumed.

This study provides the first evidence that ‘coin-flipping’ reproductive tactics occur in wild boars. The findings change the traditional view of mammalian reproductive tactics because the decoupling between phenotypic attributes and litter size and the high phenotypic variation among litter mates both suggest that developmental constraints of mammals could be less than generally assumed.

This is a clear demonstration of root herbivores affecting foliar herbivore community composition and natural enemy abundance in the field via two distinct plant-mediated nutritional mechanisms. Aphid populations, in particular, are initially driven by bottom-up effects (i.e. plant-mediated effects of root herbivory), but consequent increases in natural enemies trigger top-down regulation.

The important problems of analysing used-available data and presence-only data are equivalent, and this paper leverages this equivalence to propose advances in analysis methodology. But perhaps we should be thinking more about how best to apply a given method - applying a method in different ways can give very different results.

This study provides the first comprehensive quantification of age-specific (co)variances in reproductive success achieved through different routes in a wild population. The authors demonstrate substantial variation in the contributions of such (co)variances to the total variance in lifetime reproductive success, and that extra-pair reproduction can alter the (co)variance structure of age-specific life-histories.

This study involves multiple methods to assign natal origins to foraging leatherback turtles off the coast of eastern Canada. There are very few papers to date that use telemetry, tags and genetics in combination to do this for any species. This work highlights the importance of long-term monitoring and tagging programs in nesting and high-use foraging areas, and may help to identify where international recovery efforts may be most effective.

This paper provides insights on interspecific competition between pre- and post-dispersal consumers, an interaction that has received little attention in the dynamic consumer-resource pulse literature. The results suggest a novel hypothesis for an important multi-trophic interaction in this system that is ideal for further large-scale, integrative, multi-disciplinary ecosystem studies.

The authors quantify spatiotemporal segregation between various reproductive classes of brown bears using resource selection modelling. They find that sexually selected infanticide best explains the observed segregation, and that infanticide risk avoidance can be a very complex and fine scaled spatiotemporal mechanism. The results indicate that females with dependent young probably use human shields to lower the risk for infanticide.

While many studies of polar bird and mammalian species focus on the bottom-up effects of environmental change, impacts of predation are often overlooked. Although adult demographic rates are correlated with environmental variability, predation on pups appears to drive the current decline of an Antarctic fur seal colony.

This study of lance-tailed manakins provides the first information on the detailed effects of cooperative experience on later breeding success for any cooperatively displaying species. It also may represent the strongest test to date of the “skills hypothesis” for cooperative behaviour-proposing that individuals cooperate to gain skills that improve later breeding success - which has not been subjected to extensive rigorous testing.

The results of this study show that non-consumptive interactions can completely reverse the sign of cascading species interactions as predicted by traditional theory predicated on consumptive predator-prey interactions. This work adds a completely novel aspect to the highly topical issue of how predators influence plants and ultimately ecosystem functioning in terrestrial ecosystems.

Lemmings have long been known to indirectly affect productivity of Arctic-nesting birds, but here the authors present the first evidence for effects of lemming abundance on population size of a migratory bird species. The results illustrate the wider negative impacts of collapsing lemming cycles in several northern regions ascribed to winter climate changes.

Despite the increased recognition of scale in ecology, different scales of movement are often studied separately. Here, the authors develop theoretical predictions and a novel approach to study the role of environment to explain spatiotemporal scales of movement. They test these predictions against the movements of moose in Norway.

Using state-of-the-art tracking techniques to observe the movements of individuals from a partially migratory songbird population year-round in combination with measures of hormonal and energetic state, we provide the most detailed picture of partial migration in a free-living population.

This is one of the first large-scale experiments examining effects of forest diversity on mammalian browsing under realistic natural conditions. Strong tree species richness and species composition effects found in this study indicate that plant associational effects need to be incorporated into optimal foraging theory predicting patterns of mammalian browsing.