A study on the effects of prescribed burning on rodent community ecology was conducted in Serengeti National Park, Tanzania. The study aimed at generating ecological knowledge about the changes in rodent communities when areas of the park are intentionally burned to regulate grasslands or reduce undergrowth that can lead to uncontrolled forest fires. A completely randomized design (CRD) factorial layout with two treatments (burned and unburned) and two replications was applied. A total of 148 animals comprising six species of rodent and one insectivore were captured over 2,940 trap nights. Among the trapped individuals, 41.9% were adults, 16.1% juveniles and 41.9% sub-adults. Males and females were at parity between treatments. Species abundance was estimated using the minimum number alive (MNA) method for different rodent species and was found to vary with treatment where Mastomys natalensis declined in burned plots whilst Arvicanthis niloticus increased. However, species diversity did not differ across treatments (F1, 10 = 0.15, p = 0.70). Differences in the reproductive condition of female M. natalensis (z = 4.408, df = 15, p < 0.001) and A. niloticus (z = 2.381, df = 15, p = 0.017) were observed between treatments showing that higher numbers of reproductively active females were observed in burned plots in March, whilst in unburned plots more were observed from November to February. Conservation strategies involving periodic habitat burning should, therefore, consider small mammal reproductive periods to ensure that species potentially at risk are not adversely affected and able to rapidly recover from the effects of burning in temporarily lowering food resources and longer term impacts of increased predation caused by reduced cover.
The fate of intraperitoneally inoculated infective third-stage larvae (L,) of the nematode Brugia malayi Lichtenstein and the status of the peritoneal macrophage function were investigated in the susceptible rodent hosts Mastomys natalensis Roberts and Meriones unguiculatus Milne-Edwards (jird). Jirds and M. natalensis were inoculated intraperitoneally with 125 and 250 L, and the worm burden and peritoneal macrophage function in the two species were compared at different days post-in-oculation (DPI). None of the infected M. natalensis had adult worms in the peritoneal cavity; very few degenerating L, surrounded by peritoneal cells were recovered 7 and 15 DPI. In contrast, all the infected jirds showed the parasite in different stages of development and the worm burden at different days PI was more in 250 L, dose group than in 125 L3 dose group. The phagocytic function of peritoneal macrophages of normal M. natalensis was twice higher than that of jirds. This function was found significantly suppressed in both host species at 15 DPI; at 35 DPI, the activity was still at this low level in the jird, while that in M. natalensis reverted to uninfected age- and sex-matched control levels. These findings demonstrate that the peritoneal environment of M. natalensis is not conducive to the development of B. malayi and this is probably related to high macrophage activity in the peritoneum of this host compared to that found in the jird.