1,284 research outputs found

    Does degradation from selective logging and illegal activities differently impact forest resources? A case study in Ghana

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    Degradation, a reduction of the ecosystem’s capacity to supply goods and services, is widespread in tropical forests and mainly caused by human disturbance. To maintain the full range of forest ecosystem services and support the development of effective conservation policies, we must understand the overall impact of degradation on different forest resources. This research investigates the response to disturbance of forest structure using several indicators: soil carbon content, arboreal richness and biodiversity, functional composition (guild and wood density), and productivity. We drew upon large field and remote sensing datasets from different forest types in Ghana, characterized by varied protection status, to investigate impacts of selective logging, and of illegal land use and resources extraction, which are the main disturbance causes in West Africa. Results indicate that functional composition and the overall number of species are less affected by degradation, while forest structure, soil carbon content and species abundance are seriously impacted, with resources distribution reflecting the protection level of the areas. Remote sensing analysis showed an increase in productivity in the last three decades, with higher resiliency to change in drier forest types, and stronger productivity correlation with solar radiation in the short dry season. The study region is affected by growing anthropogenic pressure on natural resources and by an increased climate variability: possible interactions of disturbance with climate are also discussed, together with the urgency to reduce degradation in order to preserve the full range of ecosystem functions

    History, origins and importance of temporary ponds

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    In Europe, temporary ponds are a naturally common and widespread habitat occurring, often in abundance, in all biogeographical regions from the boreal snow-melt pools of northern Scandinavia to the seasonally inundated coastal dune pools of southern Spain. Ecological studies in Europe and elsewhere also emphasise that temporary ponds are a biologically important habitat type, renowned both for their specialised assemblages and the considerable numbers of rare and endemic species they support. They are, however, a habitat currently under considerable threat. Most temporary ponds are inherently shallow and the majority are destroyed even by limited soil drainage for agriculture or urban development. The paper gives an overview of definitions of temporary ponds and examines their formation and abundance. The authors also summarise a visit to the Bialowieza Forest in Poland to investigate the occurrence of temporary ponds

    Integrated fisheries, RHS and ecological data model for the River Lee

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    Arrays of Light: Betsy Schramm CD Release Concert, April 15, 2015

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    This is the concert program of the Arrays of Light: Betsy Schramm CD Release Concert on Wednesday, April 15, 2015 at 8:00 p.m., at the Tsai Performance Center, 685 Commonwealth Avenue. Works performed were the following by Betsy Schramm: Arrays of Light, Restless Airs, Light Excelleth Darkness, I. Prisms and IV. Dance from Suite for Flugelhorn, Luminous Duo, and Transformations. Digitization for Boston University Concert Programs was supported by the Boston University Humanities Library Endowed Fund

    Vertical stratification of selected Hymenoptera in a remnant forest of the Po Plain (Italy, Lombardy) (Hymenoptera: Ampulicidae, Crabronidae, Sphecidae)

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    Communities of the canopy of temperate forests are still relatively unexplored. Furthermore, very little is known on how vertical stratification for some insect groups is related to biological strategies. In this study, we investigated the community composition of both canopy and understory of the families Ampulicidae, Crabronidae and Sphecidae (Hymenoptera) of the Natural Reserve of "Bosco della Fontana", a remnant lowland forest in northeastern Italy. Observed patterns in vertical stratification have been related to species foraging habits. Our study reveals that the bulk of the community of Spheciformes of the understory consists of species predating dipterans and spiders, while species associated with the canopy are mainly predators of sap-sucking honeydew producers and epiphyte grazers, like aphids, thrips, and barkflies. Comparing the communities of canopy and understory may lead to a better understanding of species ecology and provides useful information to forest managers

    Status of coral reef fish communities within the Mombasa Marine Protected Area, Kenya, more than a decade after establishment

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    The abundance, trophic composition and diversity of fish were investigated in the Mombasa Marine Protected Area (MPA) on the Kenya coast over a period of four years (2004-2007) sixteen years after its establishment to determine its effectiveness. Fish monitoring data collected using belt transects revealed significant differences in fish abundance, distribution and composition between the MPA’s no-take area and a partially-protected area with controlled exploitation. Although seasonal variation was apparent in the trophic composition, annual differences over the four year study period were not significant. Results indicated that differences in fish composition within the MPA were due to a greater abundance of haemulids (nocturnal carnivores) and acanthurids (herbivores) in the no-take area than in the partially-protected area. Fish diversity also varied between the no-take area and the partially-protected area with a higher Shannon-Wiener diversity index associated with the no-take area. Dominance was higher in the partially-protected area than in the no-take area and was also higher during the southeast (SE) monsoon season. These results support the claim of greater effectiveness of the fully protected no-take area, compared to the partially-protected area in sustaining the rich fish community found in previous studies

    Effetti della siccità sull'abbondanza e distribuzione dei macroinvertebrati

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    The role of disturbance on structuring animal communities is a central subject in the ecological research. In particular in the intermittent systems river, the drought event seems to determine the macroinvertebrate community structure. In such context, we analysed the macrobenthos of a Sardinia intermittent stream (Rio Pula, Cagliari). The study was carried out on 16 sites in 3 years (from 2000 to 2002) with seasonal samplings (spring and autumn) of the macroinvertebrate community. The results have shown a temporal stability of community and a spatial change of community structure along the river basin determined by drought frequency. Finally, patterns of spatial change in the guild composition seem to be partly in contrast with the River Continuum concept

    Winter Conditions Influence Biological Responses of Migrating Hummingbirds

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    Conserving biological diversity given ongoing environmental changes requires the knowledge of how organisms respond biologically to these changes; however, we rarely have this information. This data deficiency can be addressed with coordinated monitoring programs that provide field data across temporal and spatial scales and with process-based models, which provide a method for predicting how species, in particular migrating species that face different conditions across their range, will respond to climate change. We evaluate whether environmental conditions in the wintering grounds of broad-tailed hummingbirds influence physiological and behavioral attributes of their migration. To quantify winter ground conditions, we used operative temperature as a proxy for physiological constraint, and precipitation and the normalized difference vegetation index (NDVI) as surrogates of resource availability. We measured four biological response variables: molt stage, timing of arrival at stopover sites, body mass, and fat. Consistent with our predictions, we found that birds migrating north were in earlier stages of molt and arrived at stopover sites later when NDVI was low. These results indicate that wintering conditions impact the timing and condition of birds as they migrate north. In addition, our results suggest that biologically informed environmental surrogates provide a valuable tool for predicting how climate variability across years influences the animal populations
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