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Filters: Tags: Proceedings of the Royal Society B: Biological Sciences (X) > Types: Journal Citation (X)

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Archived soil samples (1937-1999) and historic air quality data from the Los Angeles Basin were used for reconstructing the record of change between atmospheric NO(x) loads, soil delta(15)N values and the diversity of arbuscular mycorrhizae (AM), which are ubiquitous plant-fungus mutualists that control plant community productivity. A tripling of atmospheric NO(x) loads between 1937 and the 1970s was paralleled by soil nitrogen enrichment (delta(15)N = 3.18). From 1975 onwards, atmospheric NO(x) declined, but soils became nitrogen saturated (delta(15) N = -4 and NO(3)-nitrogen = 171mgkg(-1)). The shifts in the AM community followed 28 years of atmospheric nitrogen enrichment and coincided with the onset of soil...
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Behavioural ecologists have interpreted avian leks as products of sexual selection, in which males display socially to increase their opportunities to mate. However, without invoking reproductive queuing or kin selection, this paradigm does not necessarily explain why many males that fail to mate participate in leks. An alternative solution, that males also aggregate to reduce predation, has previously lacked compelling support. We show that mixed-species leks, comprising two congeneric grouse, form when single males or small groups of one species, the greater prairie chicken Tympanuchus cupido, join leks of another, the sharp-tailed grouse T. phasianellus. We documented the process by observing lek dynamics and...
Investigating food-limitation in generalist predators is difficult, because they can switch to alternative prey, when one of their staple prey becomes scarce. Apart from data on the dynamics of the predator population, a robust study requires: (i) a documentation of the predator's entire prey base; and (ii) an experimental or natural situation, where profitable dietary shifts are impossible, because several preferred prey species decline simultaneously. Here, we provide a detailed description of how food-supply has limited a generalist avian top predator, the northern goshawk Accipiter gentilis. In our study area, populations of several principal goshawk prey species crashed simultaneously during 1975-2000, whereas...
Although the impacts of exotic plant invasions on community structure and ecosystem processes are well appreciated, the pathways or mechanisms that underlie these impacts are poorly understood. Better exploration of these processes is essential to understanding why exotic plants impact only certain systems, and why only some invaders have large impacts. Here, we review over 150 studies to evaluate the mechanisms underlying the impacts of exotic plant invasions on plant and animal community structure, nutrient cycling, hydrology and fire regimes. We find that, while numerous studies have examined the impacts of invasions on plant diversity and composition, less than 5% test whether these effects arise through competition,...
    map background search result map search result map Active formation of mixed-species grouse leks: a role for predation in lek evolution? Active formation of mixed-species grouse leks: a role for predation in lek evolution?