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Copyright of Journal of Applied Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Determining how climate affects biotic interactions can improve understanding of drivers of context‐dependence and inform predictions of how interactions may influence plants under future climates. In arid environments, the community‐level impacts of seed predators may depend strongly on aridity; yet, long‐term studies documenting impacts of granivores on plant communities over variable climate conditions remain scarce. We evaluated how rodent exclusion interacted with climate to influence grassland and shrubland forb communities and the community‐scale distribution of seed mass over 15 years in the climatically variable northern Chihuahuan Desert. In this dynamic system, two seasonally distinct plant community phases occur annually, one in spring and the other during the summer monsoon. Rodent exclusion significantly altered the community composition of monsoon season plant communities in both grassland and shrubland, but did not affect spring plant composition. Rodents suppressed the abundance of larger‐seeded forb species and promoted smaller‐seeded species. As a consequence, rodent exclusion increased community seed mass (CWM) in monsoon forb communities, most strongly in grassland. The magnitude of impacts of rodents on seed mass varied substantially from year‐to‐year, tracking variation in climate. Specifically, rodent exclusion increased community mean seed mass the most in dry years (grassland) or in years following dry years (shrubland). Rodent exclusion had relatively weak effects on plant species diversity and richness. Our results indicate that climate interacts with the presence of rodents to structure not only the composition but also the traits of desert plant communities. [ABSTRACT FROM AUTHOR]

Seed dispersal by vertebrate animals is critical for the establishment of fleshy‐fruited plant species. In regions with impoverished faunas, such as the Patagonian temperate forest, the arboreal marsupial Dromiciops gliroides plays a key role as a seed disperser. Here, we assessed the ecological role of D. gliroides as a seed disperser and their possible effects on the plant structure of the Patagonian temperate forest. We found that the passage through the digestive tract of D. gliroides increased germination rate in four of the five groups of plants evaluated. Additionally, we found that D. gliroides disperses all the epiphytes, almost a quarter of the vines and parasites, and could disperse about half of the trees and shrubs present in the Patagonian temperate forest. Taken together, our results demonstrate the keystone dispersing role played by D. gliroides within the Patagonian temperate forest and highlight the importance of its conservation for the preservation of this highly endemic flora. [ABSTRACT FROM AUTHOR]

Dispersal is a key process in shaping species spatial distributions. Species interactions and variation in dispersal probabilities may jointly influence species spatial dynamics.However, many studies examine dispersal as a neutral process, independent of community context or intraspecific variation in dispersal behaviour.Here, we use controlled, replicated communities of two Tribolium species (T. castaneum and T. confusum) to examine how intraspecific variation in dispersal behaviour and community context influence dispersal dynamics in simple experimental landscapes composed of homogeneous habitat patches.We found considerable individual‐level variation in dispersal probability that was unrelated to body size variation. Further, the context of dispersal mattered, as T. castaneum dispersal was reduced in two‐species communities, while T. confusum dispersal was unaffected by community composition. Incorporating individual‐level variation into a two‐species stochastic spatial Ricker model, we provide evidence that individual‐level variability in dispersal behaviour results in more variable spatial spread than assuming individuals have the same dispersal probability. Further, interspecific competition resulted in more variable spatial spread.The variability in spatial spread observed in our tightly controlled and replicated experimental system and in our stochastic model simulations points to potential fundamental limitations in forecasting species shifting ranges without considering potential interspecific interactions and demographic variability in dispersal behaviour. [ABSTRACT FROM AUTHOR]

In generalized mutualisms, species vary in the quality of services they provide to their partners directly via traits that affect partner fitness and indirectly via traits that influence interactions among mutualist species that play similar functional roles. Myrmecochory, or seed dispersal by ants, is a generalized mutualism with ant species varying in the quality of dispersal services they provide to their plant partners. Variation in ant species identity can directly impact seed dispersal patterns and plant community composition; however, we know less about how interactions among seed‐dispersing ant species indirectly influence plant partners.The invasive ant Myrmica rubra, is a high‐quality seed‐disperser in its native range that interacts with myrmecochores (ant‐dispersed plants) and the high‐quality seed disperser Aphaenogaster sp. in its invaded range. We use this system to examine how interactions between two functionally similar mutualist ant species influence the recruitment and community composition of ant‐dispersed plants.We performed a field mesocosm experiment and a laboratory behavioural experiment to compare discovery and dominance behaviours between ant species, and seed dispersal and seedling recruitment of four myrmecochore species among intraspecific interaction treatments of each ant species and an interspecific interaction treatment.We found that M. rubra was better at discovering and dispersing seeds, but Aphaenogaster sp. was dominantly aggressive over M. rubra. Interspecific interactions dampened seed dispersal relative to dispersal by the better disperser. Despite this dampening, we found no effect of interspecific interactions on seedling recruitment. However, community composition of seedlings in the interspecific interaction treatment was more similar to composition in the aggressively dominant ant (Aphaenogaster sp.) treatment than in the better discoverer ant M. rubra treatment.We show that interspecific interactions between mutualist species in the same functional guild affect the outcome of mutualistic interactions with partner species. Despite the native ant dispersing fewer seeds, its dominance over the subordinate (invasive) ant has the potential to allow for some level of biotic resistance against the effects of M. rubra on plant communities when these species coexist. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Animal Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Induced plant responses to herbivory are common, and we have learned a lot about the mechanisms of induced resistance and their effects on herbivore performance. We know less about their effects on herbivore behaviour and especially on spatial patterns of damage.Theoretical models predict that induced responses can cause patterns of damage to become aggregated, random or even. A recent model predicted that informed herbivore movement coupled with communication between plants would make damage more even within individual plants. We tested these predictions in the field using a specialist beetle Trirhabda pilosa that feeds on sagebrush Artemisia tridentata. Both the beetle and the plant are well‐documented to respond to damage‐induced volatile cues.Beetle larvae were more likely to move from damaged leaves and leaves that had been exposed to volatiles from nearby damaged leaves compared to undamaged control leaves. Previous laboratory results indicated that beetles were more likely to choose undamaged leaves compared to damaged leaves or those exposed to volatile cues of damage.A comparison of damage patterns early in the season and after completion of beetle feeding revealed that variance in damage among branches decreased as the season progressed; that is, damage became more evenly distributed among the branches within a plant. Larvae damaged many leaves on a plant but removed relatively little tissue from each leaf.Herbivore movement and the spatial patterns of damage that it creates can be important in determining effects on plant fitness and other population processes. Dispersion of damage deserves more consideration in plant–herbivore studies. [ABSTRACT FROM AUTHOR]