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Many migratory herbivores seem to follow the flush of plant growth during migration in order to acquire the most nutrient‐rich plants. This has also been hypothesized for arctic‐breeding geese, but so far no test of this so‐called green wave hypothesis has been performed at the individual level. During four years, a total of 30 greater white‐fronted geese Anser albifrons albifrons was tracked using...
Although the behaviour of animals facing the conflicting demands of increasing foraging success and decreasing predation risk has been studied in many taxa, the response of pollinators to variations in both factors has only been studied in isolation. We compared visit rates of two pollinator species, hoverflies and honeybees, to 40 Chrysanthemum segetum patches in which we manipulated predation risk...
Foraging distance is a key determinant of colony survival and pollination potential in bumblebees Bombus spp. However this aspect of bumblebee ecology is poorly understood because of the difficulty in locating colonies of these central place foragers. Here, we used a combination of molecular microsatellite analyses, remote sensing and spatial analyses using kernel density estimates to estimate nest...
In experimental metacommunities with marine benthic microalgae, we tested whether heat stress changes effects of connectivity and habitat heterogeneity on metacommunity structure and functioning, by manipulating a simulated heat wave, dispersal frequency and a light intensity gradient. We found that all measures of mean local and regional diversity and community biomass significantly declined after...
Ecological communities can vary greatly in species composition. Often this variation is discontinuous, in that abrupt changes in composition occur over small distances in space or short periods of time. A wide range of hypotheses from different subfields of ecology have been proposed to explain these patterns. I suggest a framework to quantitatively evaluate these hypotheses with observational data...
Foundation species can provide habitat that modify abiotic and biotic processes that contribute to ecosystem function. While many studies have focused on the processes and consequences of a focal foundation species, understanding the ecological equivalence of co‐occurring foundation species is important to identify key species responsible for ecosystem function. Here, we investigated the relative...
Understanding the interaction between community structure and landscape structure represents a pressing theoretical challenge of great applied importance considering the increasing structural modification of ecosystems through habitat loss and fragmentation. Dispersal ability and energetic demands coupled to body size determine the landscape structure experienced by an organism, which could essentially...
Almost all eukaryotic organisms undergo sexual recombination at some stage of their life history. However, strictly asexual organisms should have higher per capita rate of reproduction compared with those that have sex, so the latter must convey some advantage which overrides the reproductive benefit of asexuality. For example, sexual reproduction and recombination may play an important role in allowing...
An individual's choice of habitat should optimize amongst conflicting demands in a way that maximizes its fitness. Habitat selection by one species will often be influenced by presence and abundance of competitors that interact directly and indirectly with each other (such as through shared predators). The optimal habitat choice will thus depend on competition for resources by other species that can...
Although spatial heterogeneity of prey and landscapes are known to contribute to variation around predator‐prey functional response models, few studies have quantified these effects. We illustrate a new approach using data from winter movement paths of GPS‐collared wolves in the Rocky Mountains of Canada and time‐to‐event models with competing risks for measuring the effect of prey and landscape characteristics...
What causes range limits is a central question in evolutionary ecology. Transplant studies indicate that areas just across range boundaries are often stressful. The recent Defense constraint (DC) hypothesis for plants states that the evolution of tolerance to stressful environments across a range boundary is constrained by allocation to chemical defense because of antagonistic crosstalk between abiotic...
Mast seeding is considered a reproductive trait resulting from several potential evolutionary forces. Although the mechanisms driving reproduction have been thoroughly investigated and discussed, their relative importance and possible coexistence remain an open question. Seed rain abundance and viability of balsam fir Abies balsamea, white spruce Picea glauca, and white birch Betula papyrifera were...
Network analysis provides a unified framework for investigating different types of species interactions at the community level. Network analysis is typically based on null models that test for specific patterns in network topology. Here we use a novel predictive approach to investigate the topology of a mistletoe–host network. It has been hypothesised that Australian mistletoes mimic the phenotype...
The two major disturbance types of boreal black spruce forest in north–central Quebec, Canada – natural disturbance by wildfire and anthropogenic disturbance by harvest – may affect processes of recovery differently and leave distinct post‐disturbance soil and vegetation spatial patterns. We tested whether 1) spatial patterns of physico‐chemical soil organic layer properties, black spruce diameter...
Because variation in age of first reproduction can have major effects on individual fitness and population dynamics, it is important to understand what maintains that variability. Although early primiparity is assumed to be costly, it is sometimes associated with high lifetime reproductive success. We used a long‐term study on bighorn sheep Ovis canadensis to determine what variables affect age at...
To determine how black‐tailed deer Odocoileus hemionus columbianus respond to phytochemical cues while browsing in heterogeneous phytochemical environments, we offered captive and free‐range deer cloned rooted cuttings and seedlings of western redcedar Thuja plicata selected for varying monoterpene content. Black‐tailed deer were thus allowed to browse among a controlled array of phytochemical cues...
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