Browsing by Author "Mwamende, K. A."

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Activity patterns and fine-scale resource partitioning in the gregarious Kihansi spray toad Nectophrynoides asperginis in captivity
(Wiley & Sons, 2014-08-01) Rija, A. A.; Goboro, E. M.; Mwamende, K. A.; Saidi, A.; Kohi, E. M.; Shombe, H. N.
Understanding the behavior of species threatened with extinction is important for conservation planning and for solving problems facing species in captivity and the wild. We examined diurnal activity budgets and habitat use of the extinct in the wild Kihansi spray toad to provide insights into ongoing conservation initiatives for this species. Observations on eight target behaviors were made each morning and evening for 14 days, in two subpopulations at Kihansi and University of Dar es Salaam captive breeding centers. There were significantly more bouts of resting than calling, amplexing, hunting, walking, climbing, or feeding. There was no difference in mean time spent in each activity between the two subpopulations. The use of habitat was variable between age classes, subpopulations and sampling time. Young toads spent significantly more time resting at the top of vegetation and on walls while adults rested
The aftermath of environmental disturbance on the critically endangered Coffea kihansiensis in the Southern Udzungwa Mountains, Tanzania
(Sagepub.com, 2011-01-01) Rija, A. A.; Shombe, H. N.; Mwamende, K. A.
The endemic Coffea kihansiensis was monitored in the Kihansi gorge over a three year period following diversion of the Kihansi River underground for hydropower production and its associated catastrophic effect on the gorge biota. We assessed the growth status of the coffee population by measuring, along an altitudinal gradient, the height and diameter of 450 randomly selected coffee stems in 18 sampling plots covering ca 1800 m2. We also collected microclimatic data to compare with that collected prior to river diversion. Coffee infestation by parasites was examined by recording the number of stems with signs of infestation. There was no significant change in size of Coffea kihansiensis during the study period. However, the size for immature plants differed between the two sites; LWF and UCF. Parasite infestation differed between reproductive age classes and was greater at lower elevation (800 – 850 m a.s.l …
Emerging issues and challenges in conservation of biodiversity in the rangelands of Tanzania
(Pensoft Publishers, 2013-11-18) Rija, A. A.; Kideghesho, J. R.; Rija, A. A.; Kideghesho, J. R.; Mwamende, K. A.; Selemani, I.
Tanzania rangelands are a stronghold for biodiversity harbouring a variety of animal and plant species of economic, ecological and socio-cultural importance. Efforts to protect these resources against destruction and loss have involved, among other things, setting aside some tracks of land as protected areas in the form of national parks, nature reserves, game reserves, game controlled and wildlife management areas. However, these areas and adjacent lands have long been subjected to a number of emerging issues and challenges, which complicate their management, thus putting the resources at risk of over exploitation and extinction. These issues and challenges include, among other things, government policies, failure of conservation (as a form of land use) to compete effectively with alternative land uses, habitat degradation and blockage of wildlife corridors, overexploitation and illegal resource extraction, wildfires, human population growth, poverty, HIV/AIDS pandemic and human-wildlife conflicts. In this paper, we review the emerging issues and challenges in biodiversity conservation by drawing experience from different parts of Tanzania. The paper is based on the premise that, understanding of the issues and challenges underpinning the rangelands is a crucial step towards setting up of plausible objectives, strategies and plans that will improve and lead to effective management of these areas. We conclude by recommending some proactive measures that may enhance the sustainability of the rangeland resources for the benefit of the current and future generations.
Floss release, seed fall and germination of Ceiba pentandra in an urban environment
(Scientific Research Publishing, 2013-09-25) Rija, A. A.; Saidi, A.; Mwita, J.; Mwamende, K. A.
The tropical forest kapok tree occurs widely in urban environments, dispersing thousands of floss during the fruiting season. However, its seedlings are rarely seen around human settlements, raising questions on what factors might be limiting its recruitment. We examined the pattern of floss release, seed fall post-dispersal and influences of watering frequency on germination of Ceiba pentandra seeds. Evening, overall, was associated with a significantly higher rate and quantity of floss release (p= 0.0001) than were mid-day and morning, correlating well with the speed of wind across the day (rh= 0.666, p= 0.001). Mean dispersal quantity differed significantly between the individual sampled trees, in which the highest dispersal was recorded from trees located in relatively open areas and the lowest was recorded in closed stand trees. Seed fall was higher within 100 m distances than seed fall farther away from dispersing trees, depending on the microsites and weather conditions. Germination started on day 5 onwards and only 15.67% of sown seeds germinated. Watering frequency strongly influenced seed germination while local human activities determined fate of dispersed seeds. We conclude that recruitment of C. pentandra species in the study area may have been limited by environmental and human factors operating at various local and spatial scales.
Notes on Feeding Habits of Spider Nephila sp in an Acacia woodland stand, Kenya
(biological research, 2012-10-06) Rija, A. A.; Mwamende, K. A.; Shombe, H. N.
AIM: To investigate the feeding habits of the spider Nephila sp and document its behavioural and ecological aspects in its natural environment. METHODS: The study was carried out in Naivasha, Kenya within the Elsamere Field Study Centre (EFSC) compound located on the southern waterfront of Lake Naivasha. We used field surveys of insects and food selectivity model to record the dietary spectrum of the spider as well as examined spider selectivity behaviour for various prey. Also, field feeding experiments were used to test whether Nephila, in its natural environment, catches trapped prey according to taxon and weight and whether prey distance from the spider determines capture in the web. RESULTS: The spider's dietary items constituted five Orders of insects, with the predator showing highest selectivity for Hymenoptera, Diptera and Coleoptera. Prey captured by the webs were significantly fewer than those available to the spider. On the average however, 1.4 insects per web spider per day were available as food for the spiders in the area, perhaps accounting for the localized and densely observed spiders. Also, distance had greatest influence on prey capture by the spider while prey weight and taxon were less important factors. These factors may have played important regulatory function in optimizing spider’s foraging success in the web. CONCLUSION: This study provides insights into understanding the behavioral and ecological aspects of the spider in the natural environment. More research done under indoor controlled environment could reveal more insights into the behavioural repertoire of this species.
Urban sprawl and species movement may decimate natural plant diversity in an Afro-tropical city
(Springer Netherlands, 2014-04-01) Rija, A. A.; Said, A.; Shombe, H. N.; Mwamende, K. A.; Madoffe, S. S.
Although urban sprawl is increasingly becoming a worldwide problem, the effects associated with urbanization on local biodiversity particularly in the developing countries, is still poorly understood. We investigated plant species richness along urban–rural gradients in an Afro-tropical metropolitan Morogoro city in Tanzania, and examined patterns of species movement by humans within and outside the city and its potential impact on habitat homogenization of urban ecosystems. Biodiversity information was assessed in 120 sample plots (25 × 25 m) distributed in core urban, sub-urban and peri-urban (rural) zones, while patterns of plant resource use and species movement were surveyed from 120 households in the study area. We found the highest tree species richness in the urban core (82.6 ± 1.4 species) whereas tree density decreased from peri-urban (465.60 ± 152.03 tree/ha) to urban core (244.00 ± …