Shrubby Cover Research Articles

Breeding habitat of a declining shorebird in a changing environment

Sub-arctic environments are undergoing rapid changes. For instance, woody shrubs are encroaching into previously open habitats, and booming goose (Chen caerulescens and Branta canadensis) populations are creating vast areas of bare mud. Across the region, these changes are likely to diminish the amount and quality of breeding habitat for imperiled arctic- and sub-arctic-breeding shorebirds, including the Hudsonian Godwit (Limosa haemastica). We studied godwit nest site selection at two study areas—Churchill, Manitoba, Canada, and Beluga River, Alaska, USA—to identify differences in habitat preferences between the two populations and determine the degree to which each avoided woody vegetation and non-vegetated areas. We used multivariate analyses to evaluate differences in microhabitat between nest sites and random sites within and between each study area. Godwits at both areas selected nest sites characterized by higher amounts of graminoid and shrubby cover with fewer non-vegetated areas than random locations. Habitat attributes preferred by godwits are expected to become less available as the climate changes and as geese continue to degrade arctic and sub-arctic ecosystems.

Composition and structure of bird communities in vegetational gradients of Bodoquena Mountains, western Brazil.

The informations of bird species distribution in different habitats and the structure of their communities are crucial for bird conservation. We tested the differences in composition, richness and abundance of birds in different phytophysiognomies at Bodoquena Mountains, western Brazil, and we demonstrated the variations in richness and abundance of birds between different trophic groups. Sampling was conducted between July 2011 and June 2012 in 200 point counts arranged in the study area. A total of 3350 contacts were obtained belonging to 156 bird species. Woodland savannas, seasonal forests and arboreal savannas had higher bird abundance and richness, while riparian forests, clean pastures and dirty pastures had smaller values of these parameters. The bird community was organized according to local vegetational gradient, with communities of forests, open areas and savannas, although many species occurred in more than one vegetation type. The insectivorous, omnivorous, frugivorous and gramnivorous birds composed most of the community. These data showed how important environmental heterogeneity is to bird communities. Furthermore, the presence of extensive patches of natural habitats, the small distance between these patches and the permeability of pastures, with high arboreal and shrubby cover, are indicated as important factors to maintain the bird diversity.

Characteristics of the organic matter of mediterranean high-mountain soils

The organic matter from the A horizons of five soils developed under a shrubby cover and under pine groves in a Mediterranean high-mountain area has been studied. The characteristics of humic acids (HA) are compared with those reported by other researchers in a variety of environmental conditions. The organic matter from pine groves has a higher C/N ratio, a greater content in fresh or littletransformed organic matter, and a lower humic extract than that of shrublands. In general, the humic acids show a low humification index, with greater relative proportion of aliphatic chains and less condensed aromatic-type structure as the pH and base saturation diminish. The climatic extremes which typify these ecosystems, very cold winters and very dry summers, together with the acidity and low base saturation of the soils, seem to be the determining causes of the low-humification index. Felbeck's hypothesis of alteration of plant components appears to be the principal process controlling the humic-acid evolution of the organic matter in these soils.

Factors Affecting Winter Pheasant Density in British Woodlands

Winter pheasant densities were obtained by drive counts in 189 sample areas of woodland from 17 sites. Measurements of woodland size, shape and structure, the extent of rearing, supplementary feeding and the habitat of the surrounding lands were recorded for each drive. Forward stepwise multiple regression and principal component analysis of 153 woods from 13 sites were used to identify factors related to winter pheasant density. On a within-site basis small woodlands with a high proportion of shrubby cover (100-200 cm in height), and the provision of supplementary feed were all associated with high pheasant densities. Pheasant density declined through the winter. On a between-site basis, high pheasant densities were associated with the release of hand-reared birds