Browsing by Author "Lobora, Alex"

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African wild dog population status in the Selous-Nyerere landscape, southern Tanzania: Insights from camera trap surveys
(Elsevier, 2025-05-03) Parsais, Singira; Searle, Charlotte; Strampelli, Paolo; Moyo, Francis; Giliba, Richard; Haule, Leonard; Olesyapa, Kandey; Salum, Nasri; Hape, Germanus; Elisa, Manase; Lobora, Alex; Cotterill, Alayne; Doody, Kathryn; Dickman, Amy
Despite being one of the world’s most endangered carnivore, there is a deficiency of recent information on the status of African wild dog (Lycaon pictus) in some of the few landscapes where viable populations are thought to still occur. One example is the Selous-Nyerere landscape in southern Tanzania, a critical stronghold for the species that has not been studied since the 1990s. We use data from seven camera trap surveys deployed over 4674 km2 in Selous Game Reserve (GR) and Nyerere National Park (NP) from 2020 to 2022 to provide an update on wild dog status in the landscape. We identified a total of 222 wild dogs, of which 38 % were male, 38 % were female, and 24 % were of unknown sex. We applied spatially explicit capture-recapture (SECR) modelling to the data from 2565 km2 of Selous GR to estimate an over-dispersion adjusted population density of 2.14 ± 0.45 adult and yearling wild dogs per 100 km2 (95 % confidence interval: 1.42 – 3.21). This study demonstrates the ways in which camera trap data can be used to improve our understanding of wild dog populations in data-limited settings, but also highlights some limitations of this data type for the species. Our findings suggest that the Selous-Niassa ecosystem is one of the most important remaining populations of wild dogs in Africa. Although this study did not directly investigate mortality, we recommend long-term monitoring and a number of conservation actions to tackle the species’ apparent threats in the landscape, and help secure this stronghold into the future.
Efficacy of land use designation in protecting habitat in the miombo woodlands: Insights from Tanzania
(Cold Spring Harbor Laboratory, 2017-03-17) Lobora, Alex; Nahonyo, Cuthbert; Munishi, Linus; Caro, Tim; Foley, Charles; Beale, Colin
Loss of natural landscapes surrounding major conservation areas compromise their future and threaten long-term conservation. We evaluate the effectiveness of fully and lesser protected areas within Katavi-Rukwa and Ruaha-Rungwa ecosystems in south-western Tanzania to protecting natural landscapes within their boundaries over the past four decades. Using a time series of Landsat satellite imageries of September 1972, July 1990 and September 2015, we assess the extent to which natural habitat has been lost within and around these areas mainly through anthropogenic activities. We also test the viability of the remaining natural habitat to provide connectivity between the two ecosystems. Our analysis reveals that while fully protected areas remained intact over the past four decades, lesser protected areas lost a combined total area of about 5,984 km2 during that period which is about 17.5% of habitat available in 1972. We also find that about 3,380 km2 of natural habitat is still available for connectivity between the two ecosystems through Piti East and Rungwa South Open Areas. We recommend relevant authorities to establish conservation friendly village land use plans in all villages surrounding and between the two ecosystems to ensure long-term conservation of these ecosystems.
Incipient signs of genetic differentiation among African elephant populations in fragmenting miombo ecosystems in south-western Tanzania
(John Wiley & Sons, Inc., 2018-07-12) Lobora, Alex; Nahonyo, Cuthbert; Munishi, Linus; Caro, Tim; Foley, Charles; Prunier, Jérôme; Beale, Colin; Eggert, Lori
Habitat fragmentation can play a major role in the reduction of genetic diversity among wildlife populations. The Ruaha-Rungwa and Katavi-Rukwa ecosystems in south-western Tanzania comprise one of the world's largest remaining African savannah elephant metapopulations but are increasingly threatened by loss of connectivity and poaching for ivory. To investigate the genetic structure of populations, we compared the genotypes for nine microsatellite loci in the western, central and eastern populations. We found evidence of genetic differentiation among the three populations, but the levels were low and mostly concerned the younger cohort, suggesting recent divergence probably resulting from habitat loss between the two ecosystems. We identified weak isolation by distance, suggesting higher gene flow among individuals located less than 50 km apart. In a long-lived species with overlapping generations, it takes a long time to develop genetic substructure even when there are substantial obstacles to migration. Thus, in these recently fragmented populations, inbreeding (and the loss of heterozygosity) may be less of an immediate concern than the loss of adults due to illegal hunting.
Modelling habitat conversion in miombo woodlands: insights from Tanzania
(Taylor & Francis Group, 2017-05-29) Lobora, Alex; Nahonyo, Cuthbert; Munishi, Linus; Caro, Tim; Foley, Charles; Beale, Colin
Understanding the drivers of natural habitat conversion is a major challenge, yet predicting where future losses may occur is crucial to preventing them. Here, we used Bayesian analysis to model spatio-temporal patterns of land-use/cover change in two protected areas designations and unclassified land in Tanzania using time-series satellite images. We further investigated the costs and benefits of preserving fragmenting habitat joining the two ecosystems over the next two decades. We reveal that habitat conversion is driven by human population, existing land-use systems and the road network. We also reveal the probability of habitat conversion to be higher in the least protected area category. Preservation of habitat linking the two ecosystems saving 1640 ha of land from conversion could store between 21,320 and 49,200 t of carbon in the next 20 years, with the potential for generating between US$ 85,280 and 131,200 assuming a REDD+ project is implemented.
Tracking animal movements using biomarkers in tail hairs: a novel approach for animal geolocating from sulfur isoscapes.
(Movement Ecology, 2020-09-18) Kabalika, Zabibu; Morrison, Thomas; McGill, Rona A; Munishi, Linus; Ekwem, Divine; Mahene, Wilson; Lobora, Alex; Newton, Jason; Morales, Juan; Haydon, Daniel; Hopcraft, Grant
Background Current animal tracking studies are most often based on the application of external geolocators such as GPS and radio transmitters. While these technologies provide detailed movement data, they are costly to acquire and maintain, which often restricts sample sizes. Furthermore, deploying external geolocators requires physically capturing and recapturing of animals, which poses an additional welfare concern. Natural biomarkers provide an alternative, non-invasive approach for addressing a range of geolocation questions and can, because of relatively low cost, be collected from many individuals thereby broadening the scope for population-wide inference. Methods We developed a low-cost, minimally invasive method for distinguishing between local versus non-local movements of cattle using sulfur isotope ratios (δ34S) in cattle tail hair collected in the Greater Serengeti Ecosystem, Tanzania. Results We used a Generalized Additive Model to generate a predicted δ34S isoscape across the study area. This isoscape was constructed using spatial smoothers and underpinned by the positive relationship between δ34S values and lithology. We then established a strong relationship between δ34S from recent sections of cattle tail hair and the δ34S from grasses sampled in the immediate vicinity of an individual’s location, suggesting δ34S in the hair reflects the δ34S in the environment. By combining uncertainty in estimation of the isoscape, with predictions of tail hair δ34S given an animal’s position in the isoscape we estimated the anisotropic distribution of travel distances across the Serengeti ecosystem sufficient to detect movement using sulfur stable isotopes. Conclusions While the focus of our study was on cattle, this approach can be modified to understand movements in other mobile organisms where the sulfur isoscape is sufficiently heterogeneous relative to the spatial scale of animal movements and where tracking with traditional methods is difficult.