Anthropogenic activities affect forest structure and arthropod abundance in a Kenyan biodiversity hotspot

Land-use change remains the main threat to tropical forests and their dependent fauna and flora, and degradation of existing forest remnants will further accelerate species loss. Forest degradation may result directly from human forest use or through spatial effects of land-use change. Understanding the drivers of forest degradation and its effects on biodiversity is pivotal for formulating impactful forest management and monitoring protocols, but such knowledge is lacking for many biodiversity hotspots, such as the Taita Hills in southeast Kenya. Here we first quantify effects of social factors (human activity and presence) at plot and landscape level, forest management (gazetted vs. non-gazetted) and spatial factors (fragment size and distance to forest edge) on the vegetation structure of indigenous Taita forest fragments. Next, we quantify effects of degraded vegetation structure on arthropod abundance and diversity. We show that human presence and activity at both the plot and landscape level explain variation in vegetation structure. We particularly provide evidence that despite a national ban on cutting of indigenous trees, poaching of pole-sized trees for subsistence use may be simplifying vegetation structure, with the strongest effects in edge-dominated, small forest fragments. Furthermore, we found support for a positive effect of vegetation structure on arthropod abundance, although the effect of daily maximum temperature and yearly variation was more pronounced. Maintenance of multi-layered forest vegetation in addition to reforestation maybe a key to conservation of the endangered and endemic fauna of the Taita Hills

Anthropogenic activities affect forest structure and arthropod abundance in a Kenyan biodiversity hotspot

Land-use change remains the main threat to tropical forests and their dependent fauna and flora, and degradation of existing forest remnants will further accelerate species loss. Forest degradation may result directly from human forest use or through spatial effects of land-use change. Understanding the drivers of forest degradation and its effects on biodiversity is pivotal for formulating impactful forest management and monitoring protocols, but such knowledge is lacking for many biodiversity hotspots, such as the Taita Hills in southeast Kenya. Here we first quantify effects of social factors (human activity and presence) at plot and landscape level, forest management (gazetted vs. non-gazetted) and spatial factors (fragment size and distance to forest edge) on the vegetation structure of indigenous Taita forest fragments. Next, we quantify effects of degraded vegetation structure on arthropod abundance and diversity. We show that human presence and activity at both the plot and landscape level explain variation in vegetation structure. We particularly provide evidence that despite a national ban on cutting of indigenous trees, poaching of pole-sized trees for subsistence use may be simplifying vegetation structure, with the strongest effects in edge-dominated, small forest fragments. Furthermore, we found support for a positive effect of vegetation structure on arthropod abundance, although the effect of daily maximum temperature and yearly variation was more pronounced. Maintenance of multi-layered forest vegetation in addition to reforestation maybe a key to conservation of the endangered and endemic fauna of the Taita Hills

The status of flora and fauna in the Nzoia River drainage basin in western Kenya

The species richness of flora and fauna in the Nzoia River drainage basin is documented through a study of museum specimens,  catalogues and databases. The catchment area and basin covers 2.2% (12900/580367 km2) of Kenya’s total land area with an altitudinal range of 1140 to 4300 m and varied ecosystem and land uses. We recorded approximately 9.3% (3239/34677) of Kenya’s current known species of vascular plants, invertebrates (insects and spiders), fish, amphibians, reptiles, birds and mammals. Bird species made up the highest proportion 58.3% (650/1114) of the national total followed by amphibians 37.3% (41/110), reptiles 45.0% (86/191), mammals 31.3% (122/390), vascular plants 17.9% (1251/7000), fish 6.7% (58/872) (32.2% (58/180) for freshwater fish only) and invertebrates (insects and spiders) 4.1% (1031/25000). Ninety-five species recorded in this area are endemic to Kenya and 42 globally threatened. The species recorded contribute to several ecosystem services including pest control, pollination, bio-indicators, medicine and cosmetics, building materials, ecotourism, research and education. Data available differed substantially across counties and taxon groups with gaps apparent in five counties (Bungoma, Busia, Elgeyo Marakwet, Siaya and Usain Gishu) and four taxa plants, invertebrates, fungi and bacteria where a dearth of information exists. To fill these gaps we recommend prioritisng future survey effort on taxa and counties with fewer than 10% of the total numbers of records