Oikos
Nutrient enrichment, ecosystem size, and richness each may directly affect the stability of both populations and communities. Alternatively, nutrient enrichment and ecosystem size each may directly affect richness, which in turn may affect stability. No previous studies, however, have tested empirically how these three factors interact and co‐determine stability. We manipulated nutrient input and...
Pollinators and their predators share innate and learned preferences for high quality flowers. Consequently, pollinators are more likely to encounter predators when visiting the most rewarding flowers. I present a model of how different pollinator species can maximize lifetime resource gains depending on the density and distribution of predators, as well as their vulnerability to capture by predators...
Nest predation has been used to explain aspects of avian ecology ranging from nest site selection to population declines. Many arguments rely on specific assumptions regarding how predators find nests, yet these predatory mechanisms remain largely untested. Here we combine artificial nest experiments with behavioural observations of individual red squirrels Tamiasciurus hudsonicus to differentiate...
The distribution of interaction strengths among community members has important consequences for assembly processes and community responses to perturbations. Species deletion from communities can trigger cascading extinction events, with strong evidence from empirical and theoretical work. I examined model competitive communities, sequentially assembled using species drawn from a global pool with...
We studied six populations of the hummingbird‐pollinated Nicotiana glauca to determine if the marked differences in the degree of floral‐pollinator mismatch between populations promote divergences in the pattern of pollinator‐mediated phenotypic selection on single traits and on the evolution of complexes of many interacting floral traits.
We found evidence that flower phenotype is being shaped by...
Metabolic theory proposes that individual growth is governed through the mass‐ and temperature‐dependence of metabolism, and ecological stoichiometry posits that growth is maximized at consumer‐specific optima of resource elemental composition. A given consumer's optimum, the threshold elemental ratio (TER), is proportional to the ratio of its maximum elemental gross growth efficiencies (GGEs). GGE...
Protection mutualisms often involve multiple species of protector that vary in quality as mutualists. Because protectors may compete for access to mutualists, concordance between competitive ability and degree of benefit will determine the overall strength of multi‐species mutualisms. We compared the abilities of two similarly sized congener ants as competitors for, and mutualists of pine‐feeding...
Patterns of clonal growth and their controls on the level of individuals have been studied thoroughly, but little is known about the actual clonal mobility of plant individuals in vegetation and about its role in generating vegetation patterns and influencing species coexistence. Current evidence shows that communities are composed of spatially nonmobile ‘matrix‐forming species’ and mobile ‘inter‐matrix’...
Life‐history traits of invasive exotic plants are typically considered to be exceptional vis‐à‐vis native species. In particular, hyper‐fecundity and long range dispersal are regarded as invasive traits, but direct comparisons with native species are needed to identify the life‐history stages behind invasiveness. Until recently, this task was particularly problematic in forests as tree fecundity and...
It has been sustained that the sticky traps present in some carnivorous plants could have evolved from ancestor species bearing leaves covered with secreting glands formerly associated with a defensive function. In this study, we evaluated the interaction of the carnivorous plant Pinguicula moranensis with its insect herbivores to assess the defensive role of the glandular trichomes. Firstly, we estimated...
We evaluated whether ecosystem engineers can accomplish two conservation goals simultaneously: (1) indirectly maintain populations of an endangered animal through habitat modification and (2) increase riparian plant diversity. We tested for effects of a prominent ecosystem engineer, the beaver Castor canadensis, on populations of St. Francis' satyr butterfly Neonympha mitchellii francisci and plant...
The number of pollinators of a plant species is considered a measure of its ecological generalization and may have important evolutionary and ecological implications. Many pollination studies report inter‐annual fluctuations in the composition of pollinators to particular species. However, the factors causing such variation are still poorly understood. Here we investigate how flowering duration and...
Leaf‐mining insects produce conspicuous and distinct leaf mines on various types of plant leaves. The diversity of leaf‐mine morphology has typically been explained by several factors, such as selective feeding on plant tissues, improvement of microclimate, faecal disposal, reduction in the efficiency of parasitoid search behaviour and leafminer phylogeny. Although these factors are certainly associated...
Recent advances in nutritional ecology, particularly arising from Ecological Stoichiometry and the Geometric Framework for nutrition, have resulted in greater theoretical coherence and increasingly incisive empirical methodologies that in combination allow for the consideration of nutrient‐related processes at many levels of biological complexity. However, these advances have not been consistently...
Several mechanisms for biological invasions have been proposed, yet to date there is no common framework that can broadly explain patterns of invasion success among ecosystems with different resource availabilities. Ecological stoichiometry (ES) is the study of the balance of energy and elements in ecological interactions. This framework uses a multi‐nutrient approach to mass‐balance models, linking...
Many recent field experiments have examined plant responses to global change factors such as climate warming, elevated atmospheric CO2, increased nitrogen addition or altered precipitation simulated at the plot level, yet the mechanisms underlying these responses can be difficult to isolate. One concern has been that the infrastructure used in these experiments can restrict the access of influential...
Homeostasis of element composition is one of the central concepts of ecological stoichiometry. In this context, homeostasis is the resistance to change of consumer body composition in response to the chemical composition of consumer's food. To simplify theoretical analysis, it has generally been assumed that autotrophs exhibit flexibility in their composition, while heterotrophs are confined to a...