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Native Plant Colonization of Eucalyptus Plantations in Farmscapes in Relation to Local, Landscape and Historical constraints: Implications for Ecological Restoration

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dc.contributor.advisor Nemomissa, Sileshi (Professor)
dc.contributor.author Telila, Habte
dc.date.accessioned 2018-07-18T08:56:42Z
dc.date.available 2018-07-18T08:56:42Z
dc.date.issued 2016-12
dc.identifier.uri http://etd.aau.edu.et/handle/123456789/9242
dc.description.abstract Agricultural expansion has caused much habitat loss across the world. Still there can be substantial levels of biodiversity in such landscapes and we need to understand more about the distribution of biodiversity in such landscapes. In some agricultural landscape there is a reforestation or afforestation trend, often with exotic trees and with the aim of generating wood products. To what extent plantations of exotic trees can harbor native biodiversity is an important question. Generally, the capacity of plantations to contain native species depend both on local, landscape and historical factors. The current study was conducted in a farmscape in central Ethiopia characterized by scattered small Eucalyptus plantations located at different distances from a remnant forest (Chilimo forest). The objectives of this study were to understand to what extent local, landscape and historical factors constrain or foster native woody and herb species regeneration in these Eucalyptus plantations. Additionally the roles of retained, isolated trees of Podocarpus falcatus and Juniperus procera as propagule sources were investigated. All native woody and herb species in 60 small (0.5-1.75ha) Eucalyptus plantations embedded in an open farmscape ranging in distance from 0.1 to 12 km from the remnant continuous forest were collected and identified. Presence/absence data on herbs was also collected in four 100 m x 50 m plots in the Chilimo forest to be used for characterization of the forest herb flora. The ages of the studied Eucalyptus plantations were estimated by using Aerial photosfrom1988-2014. The location of remnant trees of P. falcatus and J. procera were recorded within a circular plot of 500 m radius around each Eucalyptus plantations. A total of 1571 individuals of native woody plants belonging to 55 species were recorded in the plantations. The number of woody species in a plantation increased significantly with the height of the grass sward indicating sensitivity to grazing. Moreover, the number of woody species in the Eucalyptus plantations decreased significantly with distance to the forest showing that they were dispersal limited. The likelihood of presence of P. falcatus in Eucalyptus plantations increased with connectivity to retained mature trees in the surrounding area, but not so for J. procera. For the herbs a total number of 92 species were recorded in the plantations, of which 47 were denoted forest species and 45 nonforest species based on the comparison with the forest plot data. The number of forest herb species in the Eucalyptus plantations decreased with distance from the forest why this not was the case for the non-forest herb taxa. However, both the number of forest and non-forest herb species increased with the height of grass swards illustrating sensitivity to grazing also for this species groups. To conclude, sowing or planting native plants will be necessary in most plantations across the country if biodiversity of the plantations should increase and more resemble forest biodiversity, since only few remnant natural forests that could act as seed sources occur across the Ethiopian highlands. Another main obstacle might be the prohibition of selling timber of native trees, which indirectly discourage farmers from letting native trees regenerate. Thus the increasing cover of Eucalyptus seen across the country will not automatically foster a recovery of native woody plant biodiversity, even if it is managed to optimize local environmental conditions. Keywords: Chilimo forest, colonization, dispersal, farmscapes, native flora, restoration, smallscale Eucalypts plantations en_US
dc.language.iso en en_US
dc.publisher Addis Ababa Universty en_US
dc.subject Chilimo forest en_US
dc.subject Colonization en_US
dc.subject Dispersal en_US
dc.subject Farmscapes en_US
dc.subject Native flora en_US
dc.subject Restoration en_US
dc.subject smallscale Eucalypts plantations en_US
dc.title Native Plant Colonization of Eucalyptus Plantations in Farmscapes in Relation to Local, Landscape and Historical constraints: Implications for Ecological Restoration en_US
dc.type Thesis en_US


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