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Spatial and matrix influences on the biogeography of insect taxa in forest fragments in central Uganda Perpetra Akite Abstract How best to manage forest patches, mitigate the consequences of forest fragmentation, and enable landscape permeability are key questions facing conservation scientists and managers. As tropical forests become increasingly fragmented, there is a reduction in interior forest habitats, increase in edge habitats, and reduction in connectivity. Consequently, it has become increasingly apparent that understanding how species are affected by fragmentation requires information on their responses to all components of the landscape, i.e. forest patches, remaining continuous forest, and the intervening matrix. However, very little is known of how faunal communities and in particular insect assemblages utilize resources within the patch-matrix landscape. The subsequent impact of forest fragmentation on species turnover across spatial and temporal scales also remains largely unclear. The main objective of this study was to assess patterns of diversity of three insect taxa and their relation to habitat heterogeneity, disturbance gradient and how anthropogenic impacts may be altering these patterns. A combination of butterflies, moths and grasshoppers were studied as model indicators to describe patterns of diversity and distribution across the temporal, vertical and spatial scales in three forest reserves; Mabira (largely stable and recovering from past encroachment, albeit with minor illegal logging, but disturbed at the edges), Zika and Mpanga (relatively undisturbed and unchanged internally, but with substantially altered matrix), all in central Uganda. All together, 25156 individuals (327 species) of butterflies, 1131 individuals (41 species) of silkmoths, 1564 individuals (44 species) of hawkmoths and 2173 individuals (49 species) of grasshoppers were recorded across the forests and their surrounding matrix habitats. Overall, there was a marked decline in richness and abundance of species over time, even within relatively stable forests. The temporal decline was most drastic for forest-dependent species, while generalist species mostly showed the reverse trend. This change was more evident in the smallest Zika forest. There was a marked variation in species distribution within the vertical strata; more specialists were found in the canopy, despite a higher number of individuals in the understorey. This study also recorded a general decline in richness and abundance of species along a land-use gradient from mature forest to home gardens, with forest specialist species showing severe declines, and several species only restricted to the mature forests. The patterns were consistent across the different ecologically-distinct insect taxanomic groups. These findings together with similar patterns reported for other taxa in similar habitat settings indicate a worrying reduction in the capacity of protected forests to main biodiversity. Since protected forests are ecologically linked to their surrounding habitats, failure to stem broad-scale loss and degradation of these habitats will consequently increase the likelihood of serious biodiversity declines and subsequent extinction. Supervisors: Assoc. Prof. R.J. Telford Assoc. Prof. A.M. Akol Prof. Emeritus. C.H.F. Rowell