Number Of Open-habitat Species Research Articles

Diversità ornitica nei cedui di cerro utilizzati e in conversione: un confronto nell’Appennino settentrionale

Abstract: In the last decades, socio-economical changes occurred in Italy have deeply affected woodland, particularly coppices. Although most of them, above all in public land, are being converted to high forests, in the last years coppices have been experiencing an increase in their use. The claimed need to reconcile silviculture and biodiversity conservation calls for a better understanding of the effects of coppice management practices on the different components of biodiversity. Using birds as environmental indicators, we studied differences in species composition and diversity of bird communities in coppices and “transitory stands” (ex-coppices recently converted in high stands) in the Alpe della Luna forest (Arezzo), in Tuscan Apennines. Relative frequency of each species and the mean abundance and richness at point level were compared among forest typologies. To test the effects of different management types on bird communities, descriptive models (GLM) have been applied using stand age and the amount of non-forest habitats as predictors. Our results show that 34.4% of the species (57.1% considering only forest species) are affected by the forest management type: 9 species (7 considering only forest species) were more common in transitory stands, while only two (of which one considered forest species) in coppices. Overall, richness is higher in transitory stands, where species of mature forests have been found; on the contrary, coppices did not host any open habitat species, as stated in other studies. Richness in forest species is positively related to stand age for both coppice and transitory stands; the amount of open habitats is positively correlated with number of open-habitat species, but it did not negatively affect richness in forest species that apparently did not suffer for any boundary effect.

Restoration of Seminatural Grasslands: What is the Impact on Ants?

The number of species-rich seminatural grasslands in Northern Europe has decreased significantly due to the abandonment of traditional land use practices. To preserve these habitats, an increasing number of abandoned and overgrown grasslands have been restored by cutting down trees and shrubs and reintroducing grazing. These practices are considered a useful tool to recover the species richness of vascular plants, but their impact on other taxa is hardly known. Here we studied ants as one important group of grassland insects. We investigated (1) the effects of restoration of nongrazed and afforested seminatural grasslands, compared to continuously managed reference sites; and (2) the modulating impacts of habitat characteristics and time elapsed since restoration. We found a total of 27 ant species, 11 of these were characteristic of open habitats and seven characteristic of forests. Neither species richness per site nor the number of open-habitat species, nor the number of forest species differed between restored and reference sites. Yet, within the restored sites, the total species richness and the number of open-habitat species was positively related to the time since restoration and the percentage of bare rock. High frequencies of most open-habitat species were associated with low vegetation, older restored sites, and reference sites. Most forest species showed their highest frequencies in tree- and shrub-dominated habitat. We conclude that restoration efforts have been successful in terms of retrieving species richness. A regular and moderate grazing regime subsequent to the restoration is suggested in order to support a high abundance of open-habitat species.

Patterns in ground beetle (Coleoptera: Carabidae) assemblages along an urbanisation gradient in Denmark

The responses of ground beetles to an urbanisation gradient (forest-suburban area-urban park) were studied in and near Sorø, South Zealand, Denmark, during April–October 2004. The average number of species per trap did not differ significantly among the three urbanisation stages. The average number of forest species was significantly higher in the forest area (6.2 species/trap) than in either the suburban (4.12 spp/trap) or the urban (3.7 spp/trap) areas. Both the number of open-habitat species (1.8 spp/trap), and the generalist species (2.3 spp/trap) were highest in the urban area. The number of predaceous species was highest in the forest area (8.1 spp/trap), while the number of omnivorous species was highest in the urban area (0.9 spp/trap). Multivariate statistical procedures (NMDS, Sorensen similarity index) also confirmed that species composition changed remarkably along the forest-suburban-urban gradient. The highest number of species (S = 37) was found at the urban area, deviating from trends at other northern hemisphere sites (Canada, Finland) where the overall species richness was highest at the forest habitats. Urban green areas, including forest patches contribute to the quality of urban life and thus should be conserved. Apart from their recreational value, which is widely appreciated and enjoyed by human inhabitants, such green urban spaces provide seemingly adequate habitat for numerous species of ground beetles found in less developed forest areas some distance from the city core.

Changes in carabid beetle assemblages as Norway spruce plantations age

Several managed native forest stands have been reforested with conifer trees in Europe during recent centuries. These habitat alterations have influenced ground-dwelling invertebrates. We studied carabid beetle assemblages from a native beech forest (70-y-old), and a recently established (5-y-old), a young (15-y-old), a middle-aged (30-y-old) and a mature (50-y-old) Norway spruce plantation by pitfall trapping to explore the effect of reforestation on carabid beetles. The total number of carabid species, and the forest species were highest in the beech forest. The number of open-habitat species was highest in the youngest, relatively open monoculture. Ordination also confirmed changes in carabid composition with change in the studied habitats. Newly proposed forest affinity indices, based on species specificity, fidelity, and on a combination of specificity and fidelity were significantly higher in beech forest than in spruce plantations. We found these affinity indices especially useful in revealing the ecological character of the studied carabid assemblages. Regression analyses showed that leaf litter cover, herbs, shrubs, canopy closure and prey abundance were related to the structure of carabid-beetle assemblages.

The effects of extreme forest fragmentation on the bird community of Singapore Island

Singapore Island suffered one of the highest known deforestation rates in the tropics from the mid-to-late 19th century when over 95% of its native lowland forest was cleared. We compared the current bird community structure and composition among three habitat types, i.e., old (>50 years, 7–935 ha) and young (⩽50 years, 29–49 ha) naturally regenerating secondary forests and abandoned wooded plantations (27–102 ha) dominated by exotic species. Forest patch area had the strongest influence on the current species richness. The overall bird richness was not greater in most mature forest patches, but 20 species were only found in the old secondary forests and five of these were found in <50% of these patches. The rapid decrease in the number of forest species in plantations was offset by an increase in the number of open habitat species. Comparisons with current bird communities in nearby mainland forest sites (Peninsular Malaysia) suggest that the forest avifauna of Singapore is depauperate. The preservation of larger mature and maturing forests is therefore required for conserving the extant forest avifauna in Singapore. Connecting isolated patches can also be envisioned to facilitate movements of forest birds that have low densities and restricted distribution.