Effect of elephant browsing on selected species of Acacia along the great Ruaha River in Ruaha National Park, Tanzania

Elephant damage was assessed in 1,007 Acacia trees and responses between Acacia tortilis and A. kirkii in Ruaha National park were compared in 30 transects randomly placed in 38.8 km2 on the northern bank of Great Ruaha River (GRR) basing on six browsing categories and four debarking classes. There was no significant difference in browsing (F1, 10 = 0.6, p>0.05) and debarking (F1, 6 = 0.16, p > 0.05) between A. kirkii and A. tortilis. Trees were classified into three height and twelve diameter classes. About 3613 trees <1 m in height represented response in addition to coppices. The difference between the two species was observed only in regeneration potential (F1,58 = 41.4, p < 0.05). In addition, low regeneration potential, severely browsed trees and restricted distribution made A. kirkii more vulnerable to elephant feeding compared to A. tortilis. The high A. tortilis regeneration potential suggests that the study area could become an Acacia bushland or woodland if fire is controlled. Further studies need to investigate, the suppressed regeneration of Acacia trees at Msembe, variations in vegetation utilization along the GRR and effects of fire and small browsers on Acacia species including monitoring of vegetation and animal trends.Key words: Elephants, Acacia, Tree damage, Regeneration, Ruaha Rive

Buffalo, Bush Meat, and the Zoonotic Threat of Brucellosis in Botswana

Brucellosis is a zoonotic disease of global importance infecting humans, domestic animals, and wildlife. Little is known about the epidemiology and persistence of brucellosis in wildlife in Southern Africa, particularly in Botswana.Archived wildlife samples from Botswana (1995-2000) were screened with the Rose Bengal Test (RBT) and fluorescence polarization assay (FPA) and included the African buffalo (247), bushbuck (1), eland (5), elephant (25), gemsbok (1), giraffe (9), hartebeest (12), impala (171), kudu (27), red lechwe (10), reedbuck (1), rhino (2), springbok (5), steenbok (2), warthog (24), waterbuck (1), wildebeest (33), honey badger (1), lion (43), and zebra (21). Human case data were extracted from government annual health reports (1974-2006).Only buffalo (6%, 95% CI 3.04%-8.96%) and giraffe (11%, 95% CI 0-38.43%) were confirmed seropositive on both tests. Seropositive buffalo were widely distributed across the buffalo range where cattle density was low. Human infections were reported in low numbers with most infections (46%) occurring in children (<14 years old) and no cases were reported among people working in the agricultural sector.Low seroprevalence of brucellosis in Botswana buffalo in a previous study in 1974 and again in this survey suggests an endemic status of the disease in this species. Buffalo, a preferred source of bush meat, is utilized both legally and illegally in Botswana. Household meat processing practices can provide widespread pathogen exposure risk to family members and the community, identifying an important source of zoonotic pathogen transmission potential. Although brucellosis may be controlled in livestock populations, public health officials need to be alert to the possibility of human infections arising from the use of bush meat. This study illustrates the need for a unified approach in infectious disease research that includes consideration of both domestic and wildlife sources of infection in determining public health risks from zoonotic disease invasions

Abundance and diversity of wild mammals along a hydrologic gradient in the Usangu Wetlands, Tanzania

This study was conducted in the Eastern Usangu wetland in Mbeya and Iringa regions to examine the composition, abundance and diversity of mammals along a hydrological gradient. Data were collected in two seasonsusing distance sampling method along transects and a handheld GPS to locate positions. Statistical tests (t-test, Kruskal-Wallis and Pearson’s correlation) were employed to determine the association between distance and abundance of animals observed along the gradient. Diversity of mammals along the gradient was determined  by a variety of indices using PRIMER 5.0 software. The study revealed that the abundance of animals sighted decreased with distances from the edge of wetland though not statistically significant along the gradient. Flight distances of observed  mammals were high indicating higher degree of disturbances related to anthropogenic activities. Indicators of such disturbances in the wetland areaincluded abandoned farms, demolished houses and livestock dung. There was a statistically significant difference in the number of observed  mammals in the two seasons, where species richness and abundance were higher in the late dry season. These results indicate that the wetland is an important refuge area for mammals as both abundance and diversity  decreased with increasing distance from the edge of the wetland and increases during the dry season. This study recommends a continuous monitoring of birds and mammals populations such as Topi to help in determining the changes in abundance and diversity over time in Usangu wetlands as a result of conservation interventions against anthropogenic disturbances