September 15, 2017

The spotted ground thrush (Zoothera guttata; SGT) is a globally endangered forest specialist whose distribution is poorly understood in the critically endangered Indian Ocean Coastal Belt Forest (IOCBF) biome on the east coast of southern Africa. More than 70% of the IOCBF has been lost to development, resulting in fragmented forest remnants within a mosaic of different land uses. We conducted camera-trap surveys with 5796 trap-days in 82 forest patches of various sizes across a gradient of land-use types in the IOCBF during the winter seasons of 2014–2016 to establish occupancy (Ψ) of SGT. We used occupancy modelling and incorporated forest microhabitat characteristics and surrounding land-use classifications to compare sites and determine SGT distribution across the habitat mosaic. The top model estimated an average Ψ = 0.39 ± 0.09, and detection probability (P) = 0.11 ± 0.03. At the landscape scale, larger, less isolated patches had a higher Ψ of SGT while P decreased with proximity to cultivated land. At the microhabitat scale, a high percentage of bare ground influenced Ψ positively but P negatively, as did short grass cover. However, short herbaceous cover and high stem density of large (11–15 m) trees influenced P positively. These results detail the influence of landscape-scale factors including forest fragmentation and conversion to agriculture in conjunction with forest microhabitat-scale characteristics, on patch selection and distribution of a cryptic, ground-dwelling species that is both threatened and under-studied. Given its endangered status and dependence on larger and more mature forest patches, SGT may be an effective flagship species for the conservation of threatened IOCBF patches.

African catfish, Clarias gariepinus, is an important species in aquaculture and fisheries in Kenya. Mitochondrial D-loop control region was used to determine genetic variation and population structure in samples of C. gariepinus from 10 sites including five natural populations (Lakes Victoria (LVG), Kanyaboli (LKG), Turkana (LTA), Baringo (LBA) and Jipe (LJP), and five farms (Sangoro Aquaculture Center (SAN), Sagana Aquaculture Centre (SAG), University of Eldoret Fish Farm (UoE), Kibos Fish Farm (KIB), and Wakhungu Fish Farm (WKU)) in Kenya. Similarly, samples from eight localities (four natural populations: LVG/LKG, LTA, LBA, and four farmed: SAN, SAG, KIB, UoE) were genotyped using six microsatellite DNA loci. For the D-loop region, samples from natural sites exhibited higher numbers of haplotypes and haplotype diversities compared to farmed samples, and 88.2% of haplotypes were private. All except LJP and LTA shared haplotypes, and the highest number of shared haplotypes at (8) was detected in KIB. The 68 haplotypes we found in 268 individuals grouped into five phylogenetic clades: LVG/LKG, LTA, LBA, LJP and SAG. Haplotypes of farmed C. gariepinus mostly have haplotypes typical of LVG/LKG, and some shared haplotypes of the LBA population. Microsatellite analysis showed farmed samples have higher numbers of alleles than wild samples, but higher observed and expected heterozygosity levels were found in samples of natural populations. Fifteen pair-wise comparisons had significantly different FST values. All samples were in Hardy-Weinberg equilibrium. Samples from the eight localities grouped into four genetic clusters (LVG/LKG, LTA, LBA and SAG), indicating genetically distinct populations, which should be considered for aquaculture and conservation.