Historical deforestation patterns and the conservation value of church forests in the northern Ethiopian highlands

Mountain forest plants have a limited capacity for migration because altitudinal gradients usually set strict limits to plant species’ ranges and often present physical barriers against dispersal. Innate ‘islands’ of biodiversity, mountain forests are therefore particularly vulnerable to the effects of climatic change and habitat fragmentation, both key drivers of global species loss. Conservation of these ecosystems must for that reason rely on protecting not only large fragments but also small habitat patches and relictual vegetation along a wide altitudinal range.
When large fragments in such ecosystems are no longer available, small fragments become an environmental priority. Striking examples of small mountain forest fragments are the church forests of the northern Ethiopian highlands. In a landscape dominated by degraded semiarid savanna, sacred groves represent the majority of all remaining patches of Afromontane forest. Previous studies in the region only covered few fragments and could not adequately estimate the conservation value of these forests. For that reason, we digitized 394 church forests in an area of half a million hectares by systematically scanning high spatial resolution satellite images (pixel resolution 0.8 m) in eight blocks in the northern highlands and calculated area, density, shape, isolation and configuration metrics. Forest cover is only 0.2%, much lower than usually estimated in the literature (4%). Fragment shape and spatial configuration in the north and northeast of the surveyed area (irregular forests on northwestern slopes with churches near the forest edge) are consistent with forest conservation after fragmentation, while forests in the south and west (regular round forests surrounding a central church) indicate conservation prior to widespread deforestation. Fragments are small throughout the region (2.5 +- 0.2 ha) and need expansion, but known vegetation differences between church forests related to the two different historical fragmentation processes call for different strategies for forest conservation and restoration.
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Modelling of recharge areas and travel time for phreatic groundwater piezometers in Flanders in view of nitrate pollution

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Evaluation of nitrate residue norm by estimation of process factors for groundwater, Flanders, Belgium

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Conservation of the Ethiopian church forests : Threats, opportunities and implications for their management

In the central and northern highlands of Ethiopia, native forest and forest biodiversity is almost confined to sacred groves associated with churches. Local communities rely on these 'church forests' for essential ecosystem services including shade and fresh water but little is known about their region-wide distribution and conservation value. We (1) performed the first large-scale spatially-explicit assessment of church forests, combining remote-sensing and field data, to assess the number of forests, their size, shape, isolation and woody plant species composition, (2) determined their plant communities and related these to environmental variables and potential natural vegetation, (3) identified the main challenges to biodiversity conservation in view of plant population dynamics and anthropogenic disturbances, and (4) present guidelines for management and policy. The 394 forests identified in satellite images were on average ~ 2 ha in size and generally separated by ~ 2 km from the nearest neighboring forest. Shape complexity, not size, decreased from the northern to the central highlands. Overall, 148 indigenous tree, shrub and liana species were recorded across the 78 surveyed forests. Patch α-diversity increased with mean annual precipitation, but typically only 25 woody species occurred per patch. The combined results showed that >. 50% of tree species present in tropical northeast Africa were still present in the 78 studied church forests, even though individual forests were small and relatively species-poor. Tree species composition of church forests varied with elevation and precipitation, and resembled the potential natural vegetation. With a wide distribution over the landscape, these church forests have high conservation value. However, long-term conservation of biodiversity of individual patches and evolutionary potential of species may be threatened by isolation, small sizes of tree species populations and disturbance, especially when considering climate change. Forest management interventions are essential and should be supported by environmental education and other forms of public engagement.</p

Epiphytic orchid diversity found on trees and shrubs in coffee cultivated Afromontane rainforest, SW Ethiopia

The moist evergreen Afromontane forest of SW Ethiopia has become extremely fragmented and most remnants are intensively managed for cultivation of coffee (Coffea arabica). We investigated the distributions of epiphytic orchids in shade trees and their understory in forests with contrasting management intensity to determine biodiversity losses associated with coffee cultivation and to determine the capacity of coffee shrubs to act as refugia for orchid species. We studied epiphytic orchids in managed forests and natural forests and recorded orchid diversity and abundance in different tree zones of 339 trees and in the understory. Coffee management was associated with a downward shift of orchid species as orchid species were occurring in significantly lower tree zones in managed forest. The number of shrubs in the understory of managed forest was not higher than in natural forests, yet orchid abundance was higher in the understory of managed forests. Local extinctions of epiphytic orchids and species losses in the outer tree zones (a contraction of habitat) in managed forests are most likely driven by losses of large, complex-structured climax trees, and changes in microclimate, respectively. Coffee shrubs and their shade trees in managed forests are shown here to be a suitable habitat for only a limited set of orchid species. As farmers continue to convert natural forest into managed forest for coffee cultivation, further losses of habitat quality and collateral declines in regional epiphytic orchid diversity can be expected. Therefore, the conservation of epiphytic orchid diversity, as well as other components of diversity of the coffee forests, must primarily rely on avoiding coffee management intensification in the remaining natural forest. Convincing farmers to keep forest-climax trees in their coffee forest and to tolerate orchids on their coffee shrubs may also contribute to a more favorable conservation status of orchids in Ethiopian coffee agroecosystems

Management intensification in Ethiopian coffee forests is associated with crown habitat contraction and loss of specialized epiphytic orchid species

© 2015 Gesellschaft für Ökologie. The moist evergreen Afromontane forest of SW Ethiopia has become extremely fragmented and most remnants are intensively managed for cultivation of coffee (Coffea arabica). We investigated the distributions of epiphytic orchids in shade trees and their understory in forests with contrasting management intensity to determine biodiversity losses associated with coffee cultivation and to determine the capacity of coffee shrubs to act as refugia for orchid species. We studied epiphytic orchids in managed forests and natural forests and recorded orchid diversity and abundance in different tree zones of 339 trees and in the understory. Coffee management was associated with a downward shift of orchid species as orchid species were occurring in significantly lower tree zones in managed forest. The number of shrubs in the understory of managed forest was not higher than in natural forests, yet orchid abundance was higher in the understory of managed forests. Local extinctions of epiphytic orchids and species losses in the outer tree zones (a contraction of habitat) in managed forests are most likely driven by losses of large, complex-structured climax trees, and changes in microclimate, respectively. Coffee shrubs and their shade trees in managed forests are shown here to be a suitable habitat for only a limited set of orchid species. As farmers continue to convert natural forest into managed forest for coffee cultivation, further losses of habitat quality and collateral declines in regional epiphytic orchid diversity can be expected. Therefore, the conservation of epiphytic orchid diversity, as well as other components of diversity of the coffee forests, must primarily rely on avoiding coffee management intensification in the remaining natural forest. Convincing farmers to keep forest-climax trees in their coffee forest and to tolerate orchids on their coffee shrubs may also contribute to a more favorable conservation status of orchids in Ethiopian coffee agroecosystems.publisher: Elsevier articletitle: Management intensification in Ethiopian coffee forests is associated with crown habitat contraction and loss of specialized epiphytic orchid species journaltitle: Basic and Applied Ecology articlelink: http://dx.doi.org/10.1016/j.baae.2015.06.006 content_type: article copyright: Copyright © 2015 Gesellschaft für Ökologie. Published by Elsevier GmbH All rights reserved.status: publishe

Influencing factors on the nitrate residue levels in Flemish agricultural soils: a statistical analysis of 8 years of nitrate measurements

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