Browsing by Author "Giliba, Richard"

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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.
Assessing protected area effectiveness in western Tanzania: Insights from repeated line transect surveys
(wiley, 2023-08-07) Kiffner, Christian; Giliba, Richard; Fust, Pascal; Loos, Jacqueline; Waltert, Matthias
In many parts of East Africa, wildlife populations have declined over the past decades. Given these trends, site-based studies are needed to assess how protected areas with differing management strategies enable the effective conservation of wildlife populations. In Tanzania, game reserves are managed for tourist hunting, while national parks are managed for non-consumptive wildlife-based tourism. To assess the relative performance of these management strategies, we here focus on two areas: Rukwa Game Reserve (RGR) and Katavi National Park (KNP). Based on systematically designed line distance surveys in 2004 and 2021, we compared densities and group sizes of large mammal populations (African elephant, giraffe, buffalo, zebra, topi, and hartebeest) over time. Contrary to published ecosystem-wide declines observed in numerous species which considered earlier baselines, we did not detect significant population declines between 2004 and 2021. While these new results showing apparent stable populations do not invalidate earlier studies on wildlife declines, they could indicate a stabilisation phase after declines. This highlights the importance of considering appropriate temporal baselines and historical contexts when assessing conservation effectiveness.
Assessing the Ethnobotanical Uses, Harvesting Practices, and Conservation Awareness of Warburgia ugandensis in Northern Tanzania
(Scientific Research Publishing, 2024-12-09) Mollel, Letan; Munishi, Linus; Giliba, Richard
Warburgia ugandensis is unsustainably harvested commercially, threatening its survival and potentially leading to local extinction in its native range areas in Northern Tanzania. Our study aimed to assess the extent of harvesting of W. ugandensis in Northern Tanzania, ethno-botanical uses, community perceptions of species utilization, and conservation measures across its native range in Northern Tanzania. From each of the 128 randomly selected grids, we laid down a sampling plot measuring 100 m × 100 m (1 ha) for the identification, and collection of data on the extent of harvesting of W. ugandensis. Additionally, we interviewed 221 respondents using open-ended questionnaires to gather data on ethno-botanical uses, perceptions of product utilization, and conservation measures. We analyzed the data using descriptive statistics and Kruskal-Wallis tests. Our findings reveal significant variation in the extent of harvesting, with Mt. Ketumbeine experiencing the most severe harvesting while Mt. Kilimanjaro holds the highest number of intact trees. Community knowledge of the medicinal uses of W. ugandensis was highest in Mt. Kilimanjaro, particularly for treating gastrointestinal disorders, coughs, and malaria. Perceptions of species utilization were very high in Mt. Gelai and Mt. Monduli, while Mt. Kilimanjaro, Ketumbeine, and Longido showed more variability. Awareness of W. ugandensis conservation measures was high in Mt. Kilimanjaro, compared to the rest of the species’ native range areas. Therefore, our study findings underscore the urgent need for targeted conservation initiatives, particularly in regions like Mt. Ketumbeine and Mt. Longido, where W. ugandensis faces the severe extent of harvesting.
Dataset: Using dung densities to assess the ecological effectiveness of a protected area network
(Zenodo, 2024-03-05) Giliba, Richard; Kiffner, Christian; Fust, Pascal; Loos, Jacqueline
Given recent global endeavors to increase protected area coverage, it is crucial to comprehensively evaluate the efficacy of various area-based conservation strategies in effectively reducing biodiversity loss. Here, we investigated responses of wildlife populations to different protection levels and environmental variables at the landscape scale in the Katavi-Rukwa Ecosystem, western Tanzania. To this end, we conducted line distance sampling surveys and counted dung of six target mammal species (elephant, giraffe, buffalo, zebra, topi, hartebeest) along foot transects within areas differing in protection levels (from strict to less-strictly protected: national park, game reserve, forest reserve, game-controlled area, and unprotected areas). Based on these dung counts, we modelled the spatial distribution of these six mammal species using a species-specific density surface modelling framework. We, found consistent effects of protection level and land-use variables on the spatial distribution of the target mammal species: dung densities were highest in the national park and game reserves, intermediate in less-strictly protected areas and lowest in un-protected areas. Beyond species-specific environmental predictors for dung densities, our results highlight consistent negative associations between dung densities of the target species and distance to cropland and avoidance of areas in proximity to houses. Our findings underpin differences in ecological effectiveness of protected areas within one ecosystem. Protection level and land use play crucial roles in moderating the spatial distribution of all considered mammal species. Our findings suggest that a landscape approach needs to guide effective conservation across the entire protection gradient of the Katavi-Rukwa Ecosystem.
Farmers’ insights and practices on sustainable soil nutrient and pest management in semi-arid Eastern Africa
(MDPI, 2025-03-12) Ojuu, David; Mkindi, Angela; Meya, Akida; Giliba, Richard; Vanek, Steven; Belmain, Steven
The need to increase agricultural production for food, fiber, and feed for a growing population is a global call. Sub-Saharan Africa currently experiences declining soil fertility and increasing pest pressures affecting agricultural production. Soil fertility and pest management practices tend to vary greatly among smallholder farmers due to farm-based limitations, attitudes, and perceptions. Using focus group discussions and individual farmer interviews, we evaluated the socio-economic factors influencing the production and utilization of nutrient resources by smallholder farmers. We also assessed factors for pest prevalence and management by smallholder farmers. We observed that the major organic nutrient fertilizer resources used by farmers are farmyard manure and crop residue recycling. The production and utilization of organic nutrient fertilizer resources vary according to agroecological zone, influenced by livestock ownership, grazing management, and farmer organization; Farmer Research Network farmers show optimal use of nutrient resources compared to non-Farmer Research Network farmers. Pest problems varied across agroecologies and were influenced by field management gradients. We noted that FRN farmers used ecologically relevant pest management approaches more frequently than non-FRN farmers. Our findings on nutrient resources and pest management highlight context-specific issues to leverage to promote agroecological approaches for agricultural productivity and resilient semi-arid landscapes.
Forests, Farms, and Fallows: The Dynamics of Tree Cover Transition in the Southern Part of the Uluguru Mountains, Tanzania
(MDPI, 2021-05-28) Mpanda, Mathew; Kashindye, Almas; Aynekulu, Ermias; Jonas, Elvis; Rosenstock, Todd; Giliba, Richard
Forests and woodlands remain under threat in tropical Africa due to excessive exploitation and inadequate management interventions, and the isolated success stories of tree retention and tree cover transition on African agricultural land are less well documented. In this study, we characterize the status of tree cover in a landscape that contains forest patches, fallows, and farms in the southern part of Uluguru Mountains. We aimed to unveil the practices of traditional tree fallow system which is socially acceptable in local settings and how it provides a buffering effects to minimize forest disturbances and thus represents an important step towards tree cover transition. We assessed land cover dynamics for the period of 1995 to 2020 and compared tree stocking for forest patches, fallows, and farms. We found that tree biomass carbon stocks were 56 ± 5 t/ha in forest patches, 33 ± 7 t/ha in fallows, and 9 ± 2 t/ha on farms. In terms of land cover, farms shrank at intensifying rates over time for the entire assessment period of 1995–2020. Forest cover decreased from 1995–2014, with the reduction rate slowing from 2007–2014 and the trend reversing from 2014–2020, such that forest cover showed a net increase across the entire study period. Fallow consistently and progressively increased from 1995–2020. We conclude that traditional tree fallows in the study site remain a significant element of land management practice among communities, and there appears to be a trend towards intensified tree-based farming. The gains in fallowed land represent an embracing of a traditional land management system that supports rotational and alternate uses of cropping space as well as providing a buffering effect to limit over-exploitation of forests. In order to maximize tree cover and carbon stocks in the farm landscape, this well-known traditional tree fallow system can be further optimized through the incorporation of additional innovations.
Land Use and Environmental Gradients Influence on Riparian Woody Plant Diversity and Structure in Lake Manyara Watershed Ecosystem, Tanzania
(Scientific Research Publishing, 2023-09-12) Kashindye1, Almas; Giliba, Richard; Mpanda, Mathew; Rwiza, Mwemezi; Selemani, Juma
Riparian vegetations are important in supporting ecological connectivity between aquatic and terrestrial ecosystems. The structure and species composition of riparian woody plants have been subjected to multiple forces with varying degree of influences. This study examined the influence of land use and environmental gradient to the structure and composition of the riparian woody plants in northern Tanzania. A total of 270 plots were surveyed for woody plant species in the riparian ecosystems and later analysed to determine the influence of land use categories (homegarden, crop field, woodlot, open canopy forest, and closed canopy forest) and environmental variables (temperature, precipitation, elevation and slope) to the species richness, abundance, and stand parameters. Basal area was higher in woodlots, homegardens and crop fields than in the open and closed canopy forests; and as expected the reverse was true for the number of stocking density. Correlation among stand parameters with environmental variables varied significantly. Species richness and species abundance were negatively correlated to precipitation, temperature and elevation, while stocking density and basal area were positively correlated to precipitation. The study recommends continual retentions of trees on farm, further promoting of agroforestry interventions and sustainable utilization of woody plants in open and close canopy forests.
Modelling elephant corridors over two decades reveals opportunities for conserving connectivity across a large protected area network
(PLOS ONE, 2023-10-13) Giliba, Richard; Kiffner, Christian; Fust, Pascal; Loos, Jacqueline
Protected area (PA) connectivity is pivotal for the persistence of wide-ranging wildlife species, but is challenged by habitat loss and fragmentation. We analyzed habitat suitability and connectivity for the African elephant (Loxodonta africana) across PAs in south-western Tanzania in 2000, 2010, and 2019. We quantified land-use changes through remote sensing data; estimated habitat suitability through aerial survey data, remotely sensed variables and ensemble species distribution models; modelled least-cost corridors; identified the relative importance of each corridor for the connectivity of the PA network and potential bottlenecks over time through circuit theory; and validated corridors through local ecological knowledge and ground wildlife surveys. From 2000 to 2019, cropland increased from 7% to 13% in the region, with an average expansion of 634 km2 per year. Distance from cropland influenced elephant distribution models the most. Despite cropland expansion, the locations of the modelled elephant corridors (n = 10) remained similar throughout the survey period. Based on local ecological knowledge, nine of the modelled corridors were active, whereas one modelled corridor had been inactive since the 1970s. Based on circuit theory, we prioritize three corridors for PA connectivity. Key indicators of corridor quality varied over time, whereas elephant movement through some corridors appears to have become costlier over time. Our results suggest that, over the past two decades, functional connectivity across the surveyed landscape has largely persisted. Beyond providing crucial information for spatial prioritization of conservation actions, our approach highlights the importance of modeling functional connectivity over time and verifying corridor models with ground-truthed data
Modelling the impact of climate change on Tanzanian forests
(Wiley Online Library, 2020-08-31) John, Elikana; Bunting, Pete; Hardy, Andy; Roberts, Osian; Giliba, Richard; Silayo, Dos Santos
Aim: Climate change is pressing extra strain on the already degraded forest eco system in Tanzania. However, it is mostly unknown how climate change will affect the distribution of forests in the future. We aimed to model the impacts of climate change on natural forests to help inform national-level conservation and mitigation strategies. Location: Tanzania. Methods: We conducted maximum entropy (MaxEnt) modelling to simulate forest habitat suitability using the Tanzanian national forest inventory survey (1,307 oc currences) and environmental data. Changes in forest habitats were simulated under two Representative Concentration Pathways (RCPs) emission scenarios RCP 4.5 and RCP 8.5 for 2055 and 2085. Results: The results indicate that climate change will threaten forest communities, especially fragmented strips of montane forests. Even under optimistic emission scenario, the extent of montane forest is projected to almost halve by 2085, inter secting many biodiversity hotspots across the Eastern Arc Mountains. Similarly, cli mate change is predicted to threaten microhabitat forests (i.e. thickets), with losses exceeding 70% by 2085 (RCP8.5). Other forest habitats are predicted to decrease (lowland forest and woodland) representing essential ecological networks, whereas suitable habitats for carbon-rich mangroves are predicted to expand by more than 40% at both scenarios. Conclusions: Climate change will impact forests by accelerating habitat loss, and fragmentation and the remaining land suitable for forests will also be subject to pres sures associated with rising demand for food and biofuels. These changes are likely to increase the probability of adverse impacts to the country's indigenous flora and fauna. Our findings, therefore, call for a shift in conservation efforts, focusing on (i) the enhanced management of existing protected areas that can absorb the impacts of future climate change, and (ii) expanding conservation efforts into newly suitable regions through effective land use planning and land reclamation, helping to preserve and enhance forest connectivity between fragmented patches.
Multiple anthropogenic pressures challenge the effectiveness of protected areas in western Tanzania
(John Wiley & Sons, Inc., 2022-03-29) Giliba, Richard; Fust, Pascal; Kiffner, Christian; Loos, Jacqueline
Despite being key conservation instruments, the ecological effectiveness of protected areas (PAs) is contested. To assess the ecological effectiveness of PAs in the Katavi-Rukwa Ecosystem (KRE) in western Tanzania, we investigated temporal changes in land-use and population densities of six large mammal target species (elephant, buffalo, giraffe, zebra, topi, and hartebeest) across areas with different conservation category, ranging from unprotected to strictly protected. During six survey periods between 1991 and 2018, we analyzed data from remote sensing and aerial wildlife surveys to derive (i) spatiotemporal patterns of cropland cover in relation to protection category; (ii) population densities of the six-target species; and (iii) distribution of these species across protection category, land-use and environmental variables. During the surveyed period, cropland increased from 3.4 % to 9.6 % on unprotected land and from ≤0.05 % to <1 % on protected land. Wildlife densities of most, but not all target species declined across the entire landscape, yet the onset of the observed wildlife declines occurred several years before the onset of cropland expansion. Logistic regression models indicated that target species preferred the national park over less strictly PAs and areas distant to cropland. As our data do not support a direct link between land-use change and wildlife densities, additional factors may explain the apparent ecosystem-wide decline in wildlife. To bolster wildlife conservation in the KRE, we recommended proactive strategies to reduce direct threats to wildlife and cropland expansion toward wildlife dispersal areas and migratory corridors.
Population Patterns and Environmental Determinants of Warburgia ugandensis (Sprague) in Northern Tanzania
(John Wiley & Sons Ltd, 2025-09-15) Mollel, Letan; Munishi, Linus; Giliba, Richard
Warburgia ugandensis is a valuable medicinal tree native to East Africa, yet its populations are declining due to unsustainable harvesting and habitat degradation. Despite its ecological and socio‐economic importance, there is limited information on its current population status and the environmental factors shaping its distribution across different landscapes in northern Tanzania. This study assessed the population density and distribution patterns of W. ugandensis across selected mountainous regions (Mt. Kilimanjaro, Mt. Ketumbeine, Mt. Monduli, Mt. Gelai, and Mt. Longido) in northern Tanzania, and determined how these are affected by land use, elevation gradients, and environmental factors. Data collection involved stratified random sampling across elevation ranges (1000–2500 m a.s.l), encompassing diverse land‐use types (national parks, forest reserves, croplands, grazing lands, and settlements). Population density significantly varied among land‐use types, with forest reserves showing the highest densities (6.485 ± 1.628 stems/ha), significantly higher than grazing lands (1.833 ± 1.369 stems/ha). Elevation positively correlated with density, where the highest elevations (2001–2500 m a.s.l) supported the greatest density (6.937 ± 1.837 stems/ha). GLM analysis highlighted that elevation, temperature, soil organic carbon, soil pH, and nitrogen significantly influenced W. ugandensis densities. Spatial mapping revealed population hotspots around Mt. Kitumbeine and Mt. Kilimanjaro, highlighting these as priority areas for conservation. Management strategies should prioritise high‐elevation forest reserves, considering the critical environmental and soil parameters influencing W. ugandensis distribution.
Transforming Maasai Landscapes: Land Cover Changes and Their Implications for Pastoralism and Conservation
(Research Square, 2025-02-03) Giliba, Richard
Land cover change, particularly in landscapes inhabited by pastoralist communities like the Maasai, is a growing concern due to its environmental and socio-economic implications. The Maasai regions in Tanzania have experienced signi cant land cover shifts in recent years, which can affect biodiversity, ecosystem services, and traditional livelihoods. Despite the importance of these landscapes, there is limited understanding of how speci c land cover types, such as rangelands, croplands, and tree cover, have changed over time, and what the drivers behind these changes are. To address this gap, this study examines the extent and nature of land cover changes in Maasai landscapes between 2017 and 2023. The study speci cally focuses on the conversion of rangelands to other land uses, such as tree cover, croplands, and built areas, as well as the shifts from trees to cropland and built areas. By analyzing these trends, the study aims to provide insights into the factors driving land cover change and their implications for land management in the region. The ndings reveal substantial transitions, including the conversion of 451,514 hectares of rangeland to tree cover, 152,064 hectares to cropland, and 10,181 hectares to built areas. These results highlight the urgent need for strategies that support sustainable land use while considering the ecological and socio-economic importance of Maasai landscapes.
Tree Species Density and Basal Area in Image Forest Reserve, Tanzania
(EAST AFRICAN NATURE & SCIENCE ORGANIZATION, 2022-04-22) Kayombo, Canisius; Ndangalasi, Henry; Giliba, Richard; Kikoti, Imani
Abstract The tree species density and basal area form structural and functional variables of healthy forest ecosystems. Tree density and basal area are among useful parameters for management of natural forest resources. A study was carried out in Image Forest Reserve (IFR) in 2019 to determine tree species density and basal area. A total of 170 plots measuring 20 m x 40 m were set along the land cover types at an interval of 250 m from each other. Trees with a diameter at breast height (DBH - cm) ≥ 5 cm were measured for their DBH at a height of 1.3 m from ground level and used to calculate the basal area (BA) (m2). The tree individuals were used to calculate the density (D). The largest basal area was recorded from forest cover (13 279 m2 ha-1), followed by woodland (4394.09 m2 ha-1), and wooded grassland was the least). The minimum BA was recorded from woodland, while the largest was from forest (6.881 m2 ha-1). In all land cover types the DBH class (cm) >40 cm had the largest BA. Woodland had the highest density of all other land cover types, followed by forest and wooded grassland was the least. The maximum density was recorded from woodland followed by forest and wooded grassland Ospina, R., & Marmolejo-Ramos, F. (2019). Performance of some estimators of relative variability. Frontiers in Applied Mathematics and Statistics, 5, 43. Ruffo, C. K. (1991). A report on the identification of species for Image Forest Inventory, Iringa Region. Tanzania Forestry Institute. Tenzin, J., Tenzin, K., & Hasenauer, H. (2017). Individual tree basal area increment models for United Republic of Tanzania (2013). Kilolo District Council Socio-economic Profile. The Statistics for Development. The Ministry of Finance, National Bureau of Statistics of Tanzania Report. pp. 2-10. Zilliox, C., & Gosselin, F. (2014). Tree species diversity and abundance as indicators of understory diversity in French mountain forests: Variations of the relationship in geographical and ecological space. Forest Ecology and Management, 321, 105-116. PDF icon Download Article
Unlocking nature’s pharmacy: Euphorbia hirta (L.) as a potent defense against Escherichia coli and Klebsiella pneumoniae infections in Tanzania
(Elsevier, 2024) Mbwale, Issaya; Giliba, Richard; Kisula, Lydia; Kemboi, Douglas
Background Urinary tract infections (UTIs) are among the most common bacterial infections, primarily caused by Escherichia coli and Klebsiella pneumoniae, both of which have mostly developed resistance to various antibiotics. The Maasai and Meru communities in Tanzania have traditionally used Euphorbia hirta to combat resistant pathogens, particularly those causing UTIs. Purpose This study aimed to evaluate the antimicrobial compounds of aqueous extracts and the antibacterial compounds in methanolic extracts of E. hirta. We specifically focused on the antibacterial activity of aqueous and methanolic extracts against E. coli and K. pneumoniae strains, which are significant contributors to UTIs. Study design In March 2024, we randomly collected E. hirta plant parts from the Kikwe and Kisongo wards in the Arusha region of Tanzania. The samples were washed with distilled water and shade-dried for three weeks to prevent the degradation of bioactive compounds. After drying, the samples were powdered using a laboratory grinder and stored in sterile nylon bags. Methods We conducted qualitative and quantitative analyses to assess the presence of various phytochemicals, including alkaloids, saponins, coumarins, terpenoids, quinones, flavonoids, and glycosides, in the aqueous and methanolic extracts of E. hirta. To identify specific phytochemical compounds in these extracts, we used gas chromatography-mass spectrometry (GC–MS) and disc diffusion assays to test their antibacterial activity against E. coli and K. pneumoniae. Results The GC–MS analysis identified sixteen potential bioactive compounds with antibiotic properties, including dodecanal, trans-Farnesol, phytol, 13-tetradecynoic acid, methyl ester, cis-5,8,11,14,17-Eicosapentaenoic acid, 2(4H)-Benzofuranone, 5,6,7,7a-tetrahydro-4,4,7a-trimethyl-, (R)-, paromomycin, decanoic acid, methyl ester, azelaic acid, undecanoic acid, 10-methyl-, methyl ester, palmitoleic acid, 9,12,15-Octadecatrienoic acid (Z,Z,Z), 7-Hydroxy-3-(1,1-dimethylprop-2-enyl) coumarins, linoleyl methyl ketone, and 8,11,14-Eicosatrienoic acid, methyl ester (Z,Z,Z). When tested at a concentration of 1 g/mL, all extracts demonstrated significant antibacterial activity. The methanolic extract exhibited the highest performance, with a minimum inhibition zone of 12.0 ± 2.35 mm, followed by the aqueous cold extract at 9.25 ± 1.75 mm, and the aqueous boiled extract at 8.0 ± 1.35 mm. Conclusion The traditional methods employed by the Maasai and Meru communities for preparing herbal medicine from E. hirta, such as boiling and soaking in cold water, seemed to be effective in treating UTIs. Organic solvent extraction using methanol generally showed superior antibacterial activity compared to aqueous extraction. However, soaking in cold water produced extracts with higher inhibitory activity against E. coli, while boiling was more effective against K. pneumoniae. This study validates the local practices of E. hirta preparation, suggesting that water-based extracts could be both effective and safe for treating certain bacterial strains responsible for UTIs in the Arusha region