Species abundance, species richness, and ground cover were measured over 10 years on nine paired grazed and exclosure plots in short-tussock grassland in the early stages of invasion by Hieracium species. With and without grazing, H. pilosella and H. caespitosum increased markedly and H. lepidulum increased locally. In contrast, 50% of all other common species and species groups, and total, nat...

We examined patterns of shrub species diversity relative to landscape-scale variability in environmental factors within two watersheds on the coastal flank of the Santa Ynez Mountains, California. Shrub species richness and dominance was sampled at a hierarchy of spatial units using a highpowered telescope from remote vantage points. Explanatory variables included field estimates of total canop...

Farmers are key players in actions to halt biodiversity loss from farmland. However, if farmers are to sustain biodiversity, they must first be adequately informed about biodiversity and understand its drivers. Measuring biodiversity at the farm scale is difficult because of the structural complexity of many farms, and because different aspects of diversity can be considered desirable, e.g. spe...

Most efforts aimed at elucidating the factors responsible for the variation in species richness among different parasite communities have focused on host characteristics such as body mass or diet. Independently of host features, however, the way in which parasites use resources within the host may also affect the species richness of the community. The distribution of parasite individuals or bio...

In the present study the freshwater algae of Siahdarvishan River were sampled on a montly basis from December 2007 through November 2008. Three sampling stations (Gaght roudkhan , Shahkezr dame and Talab laleh ) were chosen in the river. Some physical and chemical parameters (water temperature , total hardness , nitrate , nitrite, phosphate and pH) of water samples were measured. A to...

Predatory arthropods can exert strong top-down control on ecosystem functions. However, despite extensive theory and experimental manipulations of predator diversity, our knowledge about relationships between plant and predator diversity--and thus information on the relevance of experimental findings--for species-rich, natural ecosystems is limited. We studied activity abundance and species ric...

For several epiphyte species, dispersal limitation and metapopulation dynamics have been suggested. We studied the relative importance of local environmental conditions and spatial aggregation of species richness of facultative and obligate epiphytic bryophytes and lichens within two old-growth forests in eastern Sweden. The effect of the local environment was analyzed using generalized linear ...