نتایج جستجو برای: tree species richness and abundance of herbaceous
تعداد نتایج: 24089229 فیلتر نتایج به سال:
Host trait combinations drive abundance and canopy distribution of atmospheric bromeliad assemblages
Epiphytes are strongly dependent on the conditions created by their host's traits and a certain degree of specificity is expected between them, even if these species are largely abundant in a series of tree hosts of a given environment, as in the case of atmospheric bromeliads. Despite their considerable abundance in these environments, we hypothesize that stochasticity alone cannot explain the...
the aim of this study is to investigate the tree species' diversity in a region with no management planning and introduce the calculated indices as the norm for sustainability assessment. dbh of all tree individuals, and their stories were recorded in the inventory grid (75 m × 100 m) sample plots. subsequently, richness, evenness (simpson, smith & wilson) and heterogeneity (simpson, shann...
The depletion of forest in developing countries due to extended pastures, agricultural land, fuel wood and etc. is a serious concern. Therefore planting trees for reforestation and extended forest area is a essential assignment. Forest plantation with a basic criterion affects to understory plant diversity. This effects may make some species absent or appear. The objective of this study is to a...
Explaining bird species composition and richness in eucalypt-dominated remnants in subhumid Tasmania
Aim To determine the factors influencing the distribution of birds in remnants in a fragmented agricultural landscape. Location Forty-seven eucalypt remnants and six sites in continuous forest in the subhumid Midlands region of Tasmania, Australia. Methods Sites were censused over a two-year period, and environmental data were collected for remnants. The avifauna of the sites was classified and...
As tropical rainforests are cleared, forest remnants are increasingly isolated within agricultural landscapes. Understanding how forest loss impacts on species diversity can, therefore, contribute to identifying the minimum amount of habitat required for biodiversity maintenance in human-modified landscapes. Here, we evaluate how the amount of forest cover, at the landscape scale, affects patte...
While exotic plant species often come to dominate disturbed communities, long-term patterns of invasion are poorly known. Here we present data from 40 yr of continuous vegetation sampling, documenting the temporal distribution of exotic plant species in old field succession. The relative cover of exotic species decreased with time since abandonment, with significant declines occurring 20 yr pos...
hyrcanian forests in northern slope of alborz support high bird richness and abundance same as central of europe. in this study, efficiency of different methods including fixed-width transect, variable-width transect, fixed-radius point count and variable circular plot samplings were compared in order to present the most reliable methods for surveying and monitoring of diurnal forest birds in f...
To investigate the effect of surrounding tree density and topography site host on abundance, species richness, diversity epiphytic orchids, 32 trees Schima wallichii were chosen randomly orchids counted identified. Within a circle radius 20m from each tree, with diameter at breast height (DBH) greater than 20 cm had their name DBH recorded. In addition, angle direction slope which stood measure...
We analyzed one of the longest-term ecological data sets to evaluate how forest overstory structure is related to herbaceous understory plant strategies in a ponderosa pine forest. Eighty-two permanent 1-m2 chart quadrats that were established as early as 1912 were remeasured in 2007. We reconstructed historical forest structure using dendrochronological techniques. Ponderosa pine basal area in...
In fragmented edge-dominated landscapes, nest predation and brood parasitism may reduce avian reproductive success and, ultimately, populations of some passerine species. In the fragmented agroecosystem of northwest Mississippi, placement of drop-pipe structures has been used as a restoration technique for abating gully erosion along stream banks. These actions have formed small herbaceous and ...
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