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. Scots pine (Pinus sylvestris L.) forests of northern Sweden are often considered to be N limited. This limitation may have been exacerbated by the elimination of wildfire as a natural disturbance factor in these boreal forests. Phenolic inhibition of N mineralization and nitrification (due to litter and exudates of ericaceous shrubs) has been proposed as a mechanism for N limitation of these forests,...
. The influence of fluctuating light intensities on phytoplankton composition and diversity was investigated for 49 days under semi-continuous culture conditions with sufficient nutrient supply, using phytoplankton assemblages from Lake Biwa, Japan. Light conditions were either periodically changed from high intensity (100 µmol photons m–2 s–1) to low intensity (20 µmol photons m–2 s–1) at intervals...
Nitrogen (N) limitation of primary production is common in temperate salt marshes, even though conservative N recycling can fulfill a large proportion of plant N demand. In nutrient poor young marshes, N limitation may be more severe and new N sources, such as N fixation, more important for plant growth. We measured N fixation and the response of salt marsh primary producers (Spartina alterniflora...
If herbivory is unevenly distributed among different types of plants, or if individual plants differ in their response to herbivory, herbivores may affect seedling growth and survival, and consequently plant population structure. In this study we examined variation in resistance to insect herbivory and in growth responses to feeding among 20 silver birch (Betula pendula Roth) genotypes representing...
In the New Jersey Pinelands, severely disturbed areas often do not undergo a rapid succession to forest; rather, a patchy cover of lichens, mosses and grasses persists for decades. We hypothesized that these plant covers affect soil microbial processes in different ways, and that these effects may alter the successional dynamics of the patches. We predicted that the moss and grass covers stimulate...
Models of community regulation commonly incorporate gradients of disturbance inversely related to the role of biotic interactions in regulating intermediate trophic levels. Higher trophic-level organisms are predicted to be more strongly limited by intermediate levels of disturbance than are the organisms they consume. We used a manipulation of the frequency of hydrological disturbance in an intervention...
The dark taiga of Siberia is a boreal vegetation dominated by Picea obovata, Abies sibirica, and Pinus sibirica during the late succession. This paper investigates the population and age structure of 18 stands representing different stages after fire, wind throw, and insect damage. To our knowledge, this is the first time that the forest dynamics of the Siberian dark taiga is described quantitatively...
von Bertalanffy curves were used to describe the nonlinear relationship between assemblages inhabiting holdfasts of the kelp Ecklonia radiata and the volume of the holdfast. This was done using nonlinear canonical analyses of principal coordinates (NCAP). The volume of the holdfast is a proxy for the age of the plant and, thus, the canonical axis is a proxy for succession in the marine invertebrate...
It is widely believed that wild and domestic herbivores have modified the structure and composition of arid and semi-arid plant communities of western North America, but these beliefs have rarely been tested in long-term, well-replicated studies. We examined the effects of removing large herbivores from semi-arid shrublands for 40–50 years using 17 fenced exclosures in western Colorado, USA. Shrub...
Interspecific differences in sapling growth responses to soil resources could influence species distributions across soil resource gradients. I calibrated models of radial growth as a function of light intensity and landscape-level variation in soil water and foliar N for saplings of four canopy tree species, which differ in adult distributions across soil resource gradients. Model formulations, characterizing...
When perennial herbs face the risk of being outcompeted in the course of succession, they are hypothesized to either increase their biomass allocation to flowers and seeds or to invest more in vegetative growth. We tested these hypotheses in a 3-year garden experiment with four perennials (Hypochaeris radicata, Cirsium dissectum, Succisa pratensis and Centaurea jacea) by growing them in the midst...
Changes in ecosystem functions following disturbances are of central concern in ecology and a challenge for ecologists is to understand the factors that affect the resilience of community structures and ecosystem functions. In many forest ecosystems, one such important natural disturbance is fire. The aim of this study was to understand the variation of resilience in six functional groups of invertebrates...
The early responses of the field layer to changes in biotic and abiotic conditions are key determinants of the future composition and structure of forests where sustained heavy browsing pressure has depauperated the shrub understory. We investigated the relationships between white-tailed deer density and field layer plant community dynamics in boreal forests managed for wildlife and timber production...
We examined body length differences between the beetle fauna of Eucalyptus plantation forests and remnant Eucalyptus forest in the same region using aerial and arboreal sampling. Mean body length of plantation-using species was greater than for remnant forest species, and the same pattern was apparent in the mean of all individuals collected regardless of species. This pattern was true for both Malaise-trap-collected...
We studied the disturbance associated with prairie vole burrows and its effects on grassland plant diversity at the patch (1 m2) and metacommunity (>5 ha) scales. We expected vole burrows to increase patch-scale plant species diversity by locally reducing competition for resources or creating niche opportunities that increase the presence of fugitive species. At the metacommunity scale, we expected...
The hypothesis that herbivory is higher in areas without fishing and will increase the rate at which hard coral communities return to pre-disturbance conditions was tested in and out of the marine protected areas (MPA) of Kenya after the 1998 El Niño Southern Oscillation (ENSO). Herbivory was estimated by assay and biomass methods, and both methods indicated higher herbivory in fishery closures. Despite...
Arbuscular mycorrhizal fungi (AMF) are mutualistic with most species of plants and are known to influence plant community diversity and composition. To better understand natural plant communities and the ecological processes they control it is important to understand what determines the distribution and diversity of AMF. We tested three putative niche axes: plant species composition, disturbance history,...
A growing body of evidence shows that aboveground and belowground communities and processes are intrinsically linked, and that feedbacks between these subsystems have important implications for community structure and ecosystem functioning. Almost all studies on this topic have been carried out from an empirical perspective and in specific ecological settings or contexts. Belowground interactions...
Despite numerous studies on the response of Mediterranean ecosystems to fire, few have measured the respective resilience of vegetation and fauna compartments. For 28 years, we conducted an annual monitoring of avifauna composition and vegetation structure (cover profile) following a severe wildfire in a holm oak (Quercus ilex) stand in southern France. Our aim was to estimate the time necessary for...
Despite research demonstrating that water and nutrient availability exert strong effects on multiple ecosystem processes in tropical forests, little is known about the effect of these factors on the demography and population dynamics of tropical trees. Over the course of 5 years, we monitored two common Amazonian secondary forest species—Lacistema pubescens and Myrcia sylvatica—in dry-season irrigation,...
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