How the effects of biotic factors are moderated by abiotic factors, and their consequences for species interactions, is generally understudied in ecology. A key abiotic feature of forests is regular canopy disturbances that create temporary patches, or ‘‘gaps,’’ of above-average light availability. Co-occurring in lowland primary forest of Korup National Park (Cameroon), Microberlinia bisulcata...

Many semiarid rangelands in the Great Basin, U.S.A., are shifting dominance to woody species as a consequence of land degradation including intense livestock grazing and fire suppression. Whereas past rehabilitation efforts in Big sagebrush (Artemisia tridentata) steppes removed the shrub and added introduced forage grasses to successfully shift communities from shrublands to grasslands, curren...

Understanding the complex mechanisms controlling treeline advance or retreat in the arctic and subarctic has important implications for projecting ecosystem response to changes in climate. Changes in landcover due to a treeline biome shift would alter climate feedbacks (carbon storage and energy exchange), ecosystem services such as wildlife and berry habitat, and landscape flammability. Wildfi...

The life histories of many species depend first on dispersal to local sites and then on establishment. After dispersal, density-independent and density-dependent mortalities modify propagule supply, determining the number of individuals that establish. Because multiple factors influence recruitment, the dichotomy of propagule versus establishment limitation is best viewed as a continuum along w...

1 Multiple factors are known to influence tree seedling establishment, yet the degree to which these factors depend on each other and on spatial context is largely unknown. We examined the influence of herbaceous competition and water and nitrogen limitations on tree seedling establishment as functions of distance from trees (within-site spatial context) and site history (between-site spatial c...

Forest community structure may be influenced by seedling density dependence, however, the effect is loosely coupled with population dynamics and diversity in the short term. In the long term the strength of conspecific density dependence may fluctuate over time because of seedling abundance, yet few long-term studies exist. Based on 11 years of seedling census data and tree census data from a 2...

PROBLEM: Eelgrass (Zostera marina) seeds are being used in a variety of both smalland large-scale restoration activities and have been successfully used to initiate recovery of eelgrass in the Virginia seaside coastal lagoons, which lost eelgrass in the 1930s ‘wasting disease’ pandemic (Orth et al. 2006a). However, a major bottleneck with the use of seeds has been the relatively low rate of see...

Studies simultaneously evaluating the importance of safe-site and seed limitation for plant establishment are rare, particularly in human-modified landscapes. We used spatially explicit neighborhood models together with data from 10 0.5-ha mapped census plots in a fragmented landscape spanning 1000 km2 to (1) evaluate the relative importance of seed production, dispersal, and safe-site limitati...

wormwood sagebrush (artemisia sieberi besser) is one of the most widely distributed shrub species in iran and turkistan steppes, its establishment on dry lands has generally been proven difficult because of low seedling vigor, inability to compete with herbaceous species, poor seed quality, and altered edaphic conditions. in order to evaluation of planting methods and seedling establishment, se...

Several factors decrease plant survival throughout their lifecycles. Among them, seed dispersal limitation may play a major role by resulting in highly aggregated (contagious) seed and seedling distributions entailing increased mortality. The arrival of seeds, furthermore, may not match suitable environments for seed survival and, consequently, for seedling establishment. In this study, we inve...