Sengwa Wildlife Research Area Research Articles

Modelling Poaching Risk Zones in Sengwa Wildlife Research Area: A Progressive Step towards Poaching Management

Modelling Poaching Risk Zones in Sengwa Wildlife Research Area: A Progressive Step towards Poaching Management

Dynamics and determinants of human–hyaena conflicts in the surroundings of a protected area

AbstractHuman–wildlife conflicts (HWC) predominate in areas proximal to wildlife rich protected zones. Whereas herbivore driven HWC is easy to detect, the stealth, nocturnal and predacious nature of carnivores leads to human injury and fatality, livestock depredation and loss of livelihoods in communities proximal to Sengwa Wildlife Research Area (SWRA) in northwest Zimbabwe. This study aimed to: (1) determine the nature of human–hyaena conflicts (HHCs), (2) explore the drivers of HHCs and (3) investigate the spatial and temporal movement patterns of hyaenas in HHC hotspots in areas proximal to SWRA. The results indicated that prevalent HHC types include livestock depredation, property damage, harassment, nuisance and disruption of human movements around SWRA. Locals indicated removal of park fences, human settlement on wildlife migration corridors, increases in hyaena populations, easy stray livestock targets, increased poaching and removal of natural wildlife death carcasses by illegal hunters as key drivers of HHC. Hyaenas have a predetermined non‐seasonal movement pattern following traditional wildlife migration corridors through SWRA into proximal communities. Human–hyaena conflict abatement strategies should be underpinned by indigenous local knowledge of hyaena movement and hunting patterns. Integrating citizen science data and remote sensing techniques aids to track and understand movement and hunting patterns of hyaenas inside and outside of protected areas.

Spatial distribution of invasive large fever berry trees (Croton megalobotrys) in Sengwa Wildlife Research Area: Gokwe, Zimbabwe

BackgroundThe invasion of rangelands by invasive plant species is a major threat to biodiversity in most parts of Zimbabwe posing not only an ecological challenge but a growing management and eradication challenge as well. However, there is sparse information relating to the spatial distribution of these species and the conditions promoting their growth and development particularly in Sothern Africa. The study assessed the spatial distribution of the invasive large fever berry tree and associated soil type in Sengwa Wildlife Research Area. A mixed methods research design triangulating qualitative and quantitative methods was utilized. All known sites occupied by large fever berry trees were obtained from the Sengwa Wildlife Research Institute’s records on invasive plant species. Ground truthing was done for all sites and global positioning system coordinates of occupied areas were collected. Mapping of invaded areas by the large fever berry tree was done using Quantum GIS software. Coordinates were imported to show points with the large fever berry tree. Altitude of invaded areas and soil samples were also collected for soil analysis and a soil texture triangle was used to come up with the soil type associated with the growth and spread of the large fever berry trees.ResultsThe results show that the large fever berry tree occupied areas along major rivers and streams on loam soils. An area of 16.5km2 which is 4.4% of the Sengwa Wildlife Research Area is invaded by the large fever berry tree. Results further indicated that sandy- loam soils were associated with the growth and development of the large fever berry tree in Sengwa Wildlife Research Area. Veld fires were also identified as a factor influencing the spread of the large fever berry tree species in the Sengwa Wildlife Research Area.ConclusionIn conclusion, a holistic framework was developed to curb the invasion of the large fever berry tree in Sengwa Wildlife Research Area. It is recommended that further studies be conducted outside the protected area to establish soil characteristics and invasion rates in order to fully understand drivers of its invasion.

Livestock Losses and Predation Crisis in Communal Areas around Sengwa Wildlife Research Area (SWRA), Zimbabwe

Livestock Losses and Predation Crisis in Communal Areas around Sengwa Wildlife Research Area (SWRA), Zimbabwe

Effects of Prescribed Burning on Abundance of Common Herbivores in Matekenya Vlei, Sengwa Wildlife Research Area (SWRA), Zimbabwe

Effects of Prescribed Burning on Abundance of Common Herbivores in Matekenya Vlei, Sengwa Wildlife Research Area (SWRA), Zimbabwe

Spatial Distribution of Invasive Large Fever Berry Trees (Croton Megalobotrys) in Sengwa Wildlife Research Area: Gokwe, Zimbabwe

Spatial Distribution of Invasive Large Fever Berry Trees (Croton Megalobotrys) in Sengwa Wildlife Research Area: Gokwe, Zimbabwe

Topo-edaphic, Vegetation Cover and Type Influence on Spatial Distribution of Gullies in Sengwa Wildlife Research Area (SWRA), North West Zimbabwe

Gully erosion is a common phenomenon in arid and semi-arid areas and is mostly influenced by soil type, topography, vegetation type and cover. The objective of the study was to determine the effect of topo-edaphic, vegetation type and cover on gully occurrence, hence map their spatial distribution in SWRA. A conventional method was used where field visit to known gully sites was done. At each site, GPS points were marked at three points, that is, at the head site, the middle and lower end of the gully. Soil samples, gully width, depth, length, vegetation type and cover were recorded for each point where GPS coordinates were collected. GPS points were overlaid on SWRA processed vegetation, soil and topographic map for analysis on the spatial distribution of gullies. Fifty-six gullies were recorded with highly affected areas on the southwestern side of the park. Associated soils types were clay and loam of the Madumabisa mudstone, colluvial and alluvial located at altitudes below 1000 meters. Gully occurrences were sighted more in mopane dominated woodlands with few recorded in areas dominated by acacia woodlands and on the edges of miombo woodlands, which occupy the high grounds of SWRA. Gully length varied from 20m in less developed gullies to 2520m for mature gullies with volumes ranging between 52m3 and 4649.4m3. Hence, topography, soil type, vegetation cover and type influence gully location and occurrence. Future research should aim to monitor changes in gully development using remote sensing as it provides a great potential for monitoring gully changes across the landscape.

Assessment of Big Cats Abundance and Distribution in Sengwa Wildlife Research Area (SWRA): An Analysis of Multiple Methods

Large carnivores are considered key species and their presence signify health of the ecosystem. Mostly used methods to establish big cats abundance and spatial distribution in SWRA consist of spoor survey, individual observations, analysis of patrol data and interviews with safari operators. In this study, four methods were used to establish current abundance and distribution of big cats in Sengwa and to find advantages and disadvantage for each method used. To do this, spoor survey along twelve transects were done between 13th to 20th April 2020. Oral interviews with local professional hunters and park managers was done between 1st and 10th April 2020, whilst analysis of patrol reports from January 2018 to December 2019 were also done. Descriptive statistics was used for analysis of interview data. For other three methods, data were summarised in excel and quantitatively analysed. Mapping of spatial distribution of big cats from secondary data and spoor surveys were done in QGIS software. Five lion spoors and twenty-one leopard spoors were recorded during spoor survey. Two individual leopards and zero lions were also recorded. Lion spoors were mostly recorded along river valleys while leopard spoors were recorded in different habitats and terrain. Future related studies should focus on use of other survey design and combination of methods such as radio calls and camera traps as well as use of GPS enabled collars for monitoring and estimating abundance.

An Analysis of the Factors Contributing to Elephant Population Fluctuations in SWRA using Ranger-based Knowledge and Perceptions

This study aimed at examining local ranger-based knowledge and perceptions on explaining contributing factors to variations on elephant fluctuations seasonally and over a long period in Sengwa Wildlife Research Area following a massive decline of elephants by nearly 76% after the 2014 National Aerial Survey done in Sebungwe Region, Zimbabwe. Data were collected between 1st and 20th August 2020 using a purposive sampling approach administered to questionnaire to resident SWRA rangers (n = 25). Our results show that rangers considered a combination of factors that may have affected elephant fluctuations in SWRA including poaching, migration, settlement and impact of climate change. However, our results suggest that rangers had inadequate knowledge about elephant migration destinations. Moreover, mixed perceptions about the impact of trophy hunting, poaching and climate change-induced factors were recorded from the participants. The results contribute to a growing understanding of poaching, climate change, trophy hunting and human settlement on elephant behaviour. The study recommends improvement in elephant monitoring through investments in elephant collars and radio tracking to better understand elephant daily and seasonal dispersal movements.

An Analysis of the Influence of Annual Rainfall Fluctuations on Wildfire Occurrence in Protected Areas in the Northwest of Zimbabwe

The occurrence and threat from wildfires are a conservation concern in semi-arid savanna-protected areas. The risk of wildlife occurrence is uncertain under climate change scenarios. However, general predictions are that different changes are likely to occur in weather conditions in different landscapes. We sought to analyze the influence of annual precipitation on wildfire occurrence in a protected area landscape in northwest Zimbabwe. Data on annual rainfall received and wildfire occurrence for Chizarira National Park (CNP), Chirisa Safari Area (CSA), and Sengwa Wildlife Research Area (SWRA) was analyzed using regression analysis. The relationship between the annual precipitation amount received per site and the number of wildfires recorded per site showed a positive correlation only for CSA. No significant differences were observed for CNP and SWRA at a significant level of p< 0.05. The highest number of wildfires were recorded between July and November. We advance that annual rainfall is one factor among many drivers of wildfires and that this is not uniform but varies across the landscape. Effective annual precipitation contributes to high vegetation biomass production and accumulation of such biomass increases the risk of wildfires. In some instances, rainfall patterns could not explain the occurrence of wildfires. We, therefore, contend that other drivers such as human activities and natural factors are important drivers of wildfires across the three sites. The conservation implication of our finding is that robust fire management plans need to take an ecosystem approach that includes communities adjacent to protected areas.

Decline and Die-Back of Woody Plants in a Physiognomic and Floristically Complex Sebungwe Region and the Factors Modifying Mosaic Patch Landscapes at Sengwa Wildlife Area, Zimbabwe

An investigation of the status of woodlands at Sengwa Wildlife Research Area (SWRA) revealed factors influencing decline and die-back of woody plants at a time of low elephant densities. The vegetation condition of the study area in the elephant range area of the semi-arid area of northwest Zimbabwe was randomly assessed in 50 × 20 m permanently marked degraded and undegraded plots in a study area approximately 80 km2. Diversity of woody plants increased towards downstream. Percentage elephant damage was slight on undegraded plots and termite damage was three times greater on undegraded plots than degraded plots. Density of woody plants was high following a period of coppice regeneration. The results suggest regeneration of woody plants following a long period of elephant culls between 1960 and 1992 that altered forest structures. It is conceivable that other environmental agents may play the role of elephant damage in the presence of elephant densities < 1 individuals/ km2. Significant differences (p<0.05) in elephant densities (no/km2) were recorded in SWRA between 1958 and 1996, 1958 and 1993 suggesting that increasing elephant densities were negatively impacting on woody cover (%). Woody cover increased from 60% in 1993 to 70% in 1996 inside SWRA. SWRA vegetation may be on regeneration path if no adverse impacts are recorded from other environmental agents including termite activity, fungal attack (Fusarium oxysporum), Lantana camara L. invasions and drought. Epidemic die-back is not yet a common feature in the protected area. The results refute the postulation that elephant alone prevent woodland regeneration and recruitment into larger size classes by feeding on small trees. The findings suggest need to consider end to end cycle of each disturbance factor in order to accurately predict scale of vegetation change in savanna ecosystems.

Evaluation of the effectiveness of an early peripheral burning strategy in controlling wild fires in north‐western Zimbabwe

AbstractA review of the occurrence of wild fires in Sengwa Wildlife Research Area (SWRA), Zimbabwe, is presented for the period 1965–1993. The effectiveness and desirability of early burning of peripheral areas introduced in 1979 are evaluated. More than 75% of wild fires occurred between July and October, 48.6% of which originated from communal lands. Early burning of peripheral areas led to significant reductions in extent of areas burnt, from annual mean areas of 115 km2 (1965–1978) to 11 km2 (1979–1993) because of effective control of fires, which originated from communal lands. Some areas did not burn at all after 1979, and the overall probability of burning dropped from 0.484 to 0.187. Whilst it may be desirable to keep fires out of SWRA in the short term, fuel build‐ups increase the fire hazard resulting in negative consequences on biodiversity in the long term. Consideration should be given to combine peripheral burning with low‐intensity prescribed burning of selected blocks to keep a semblance of natural fire regimes to ensure the maintenance of biodiversity while simultaneously reducing the fire‐hazard. An integrated fire management plan should be put in place for SWRA.

Free-ranging domestic dogs ( Canis familiaris) as predators and prey in rural Zimbabwe: threats of competition and disease to large wild carnivores

Domestic dogs ( Canis familiaris) arrived in Zimbabwe ca. 1000 years ago. Numbers of free-ranging dogs have reached unprecedented levels in communal lands (agro-pastoralist rural areas), and interact with large wild carnivores along boundaries with wildlife reserves as predators and prey. This study examined a population of 236 dogs in a 33-km 2 section of Gokwe Communal Land (GCL) bordering the Sengwa Wildlife Research Area (SWRA) in north-western Zimbabwe in 1995–1996. Dogs were found up to 6 km within the SWRA, and were the most common carnivore on the GCL–SWRA boundary. Observations of 16 radio-collared dogs showed that they were inefficient predators. Only 20 kills were recorded amongst the remaining dog population, of which three were wild ungulates. Dogs were unsuccessful predators due to their small group size (mean 1.7) and body mass (mean 14.7 kg), and the abundance of alternative food. It is therefore unlikely that they compete with large carnivores for wild prey. However, leopards ( Panthera pardus), lions ( P. leo) and spotted hyaenas ( Crocuta crocuta) preyed on dogs in GCL, removing ⩾6% of the dog population in 1993. Such predation provides ideal circumstances for disease transmission. Canid disease was prevalent in the study area; including rabies and probably distemper. The risk of infection is greatest during the dry season (May–October), when peaks in rates of disease, carnivore incursions into GCL, and predation on dogs coincided. The role of jackals ( Canis adustus and Canis mesomelas) and spotted hyaena predation of dogs is discussed in relation to disease epidemics within wildlife reserves. With a dog population growth rate of 6.5% per annum, and the prevalence of canid diseases, the conservation threat posed by dogs is escalating on communal land–wildlife reserve boundaries in Zimbabwe. Measures to control dog numbers and improve vaccination coverage of dogs are discussed.

Changes in miombo woodland cover in and around Sengwa Wildlife Research Area, Zimbabwe, in relation to elephants and fire

AbstractOne of the consequences of impacts of elephants and fire on woodlands is a change in woody cover, which often results in major challenges for wildlife managers. Changes in miombo woodland cover in and around Sengwa Wildlife Research Area (SWRA) between 1958 and 1996 were quantified by analyzing aerial photographs. Woody cover in SWRA decreazed from 95.2% in 1958 to 68.2% in 1996, with a lowest mean of 62.9% in 1983. The annual absolute rate of woody cover change in SWRA increazed from −1.1% per annum between 1958 and 1964 to a recovery of 1.6% per annum between 1993 and 1996, while the annual relative rate increazed from −1.1% per annum between 1958 and 1964 to 3.3% per annum between 1993 and 1996. There was a strong negative correlation between elephant densities and woody cover in SWRA, suggesting that loss of woody cover was mainly due to elephants. Woodland recovery after 1983 was due to reductions in elephant populations through legal and illegal off‐take and reductions in fire frequency. Surrounding areas experienced less woody cover losses than SWRA, mainly due to tree removal by locals whose densities increazed after the eradication of tsetse fly in the 1970s.

Diet of free-ranging domestic dogs (Canis familiaris) in rural Zimbabwe: implications for wild scavengers on the periphery of wildlife reserves

Numbers of free-ranging dogs (Canis familiaris) have reached unprecedented levels in Zimbabwean communal lands (agropastoralist rural areas). This study examined the potential competitive interactions between dogs and wild scavengers on the boundary of Gokwe Communal Land (GCL) and the Sengwa Wildlife Research Area (SWRA) in 1995–96. Dietary studies showed that dogs were primarily scavengers of human waste and animal carcasses. Twelve experimental carcasses indicated that dogs were the most successful species in the vertebrate scavenger guild, consuming 60% of available biomass and finding 66.7% of carcasses. Dogs monopolized the supply of domestic animal carrion within GCL, but also consumed wild carrion up to 1 km within the SWRA, and were seen 3 km inside the reserve. Their principal competitors for carcasses were vultures, and to a lesser degree lions (Panthera leo), leopards (P. pardus) and spotted hyaenas (Crocuta crocuta). Dogs outcompete vultures on wildlife reserve boundaries owing to their high densities, nocturnal and diurnal activity, physical dominance and greater tolerance of human disturbance. With a population growth rate of 6.5% per annum the influence of dogs will intensify on the peripheries of reserves, exacerbating their existing threat to wild scavengers. This scenario is probably occurring in many other African countries.

Low survival rate and high predation in the African hingeback tortoiseKinixys spekii

AbstractLive and deadKinixys spekiiwere collected in the Sengwa Wildlife Research Area, Zimbabwe over a 12‐year period. Live tortoises were sexable at a midline plastron length of 100 mm; females were considered sexually mature at 140 mm (reached by age 9 years) and males at 120 mm (at age 7 years). Adult females were significantly larger than males, on average by 14 mm in length and by 1.43 times in mass. Mark–recapture analysis in a 2 km2area showed a population density of sexable tortoises of 0.16 ha−1. The survival rate was estimated by recaptures, by the frequency distribution of age at death, and by the mean age of live tortoises, and averaged 0.74 year−1. Seventy‐seven to 89% of dead tortoises showed evidence of predation, depending on the criteria used. Damage occurred in characteristic forms, loss of the front or rear of the plastron, or holes in the carapace and plastron, which were attributed to predation by mammals and ground hornbills, respectively.K. spekiihad similar body size and sexual size dimorphism to Mediterranean tortoises (Testudo), but population density was much lower and the mortality rate was twice as high, probably due to the abundant African predators. High mortality was offset by a rate of juvenile growth twice that ofTestudo.

The economic costs of wildlife predation on livestock in Gokwe communal land, Zimbabwe

In areas bordering wildlife reserves in Zimbabwe, agro‐pastoralists suffer livestock depredation by wild carnivores. However, the economic value of these losses, and therefore the levels of compensation required has never been calculated. Between January 1993 and June 1996 in a 33‐km2 area of Gokwe communal land bordering the Sengwa Wildlife Research Area, 241 livestock were killed by wild carnivores. Baboons (Papio ursinus Kerr), lions (Panthera leo Linnaeus) and leopards (P. pardus Linnaeus) were the most serious predators, contributing 52%, 34% and 12% of kills, respectively. Baboons only killed young goats (Capra hircus Linnaeus) and sheep (Ovis aries Linnaeus) by day, while lions and leopards jumped into fortified kraals at night and killed cattle (Bos indicus Linnaeus), donkeys (Equus asinus Linnaeus) and smallstock. In 1995, predators killed 5% of livestock holdings, double that recorded by other African studies. The annual total value of losses depended upon the degree of lion predation on the most valuable species, cattle and donkeys. The average annual loss per livestock‐owning household was US$13, or 12% of each household's net annual income. Losses could be reduced by improving kraal defences against lion and leopard predation in the dry season, when attacks were most common.

Small mammals of a woodland‐savannah ecosystem in Zimbabwe. II. Community structure

Community characteristics of small mammals in five woodland‐savannah habitats (riverine grassland, miombo, mopane, talus, thicket) were studied at Sengwa Wildlife Research Area in Zimbabwe between July 1992 and July 1993. The study was initiated following a drought year and extended over a year of average rainfall. Fourteen species of small mammals were recorded during mark‐and‐recapture trapping, with the number of species known to occur in a single community ranging from three to nine. Species complements and biomass (g/ha) were lowest during the first portion of the study and peaked during the 1993 cool dry season. Species diversity (H') was lowest in the hot dry season and highest in the cool dry season. Temporal variation in biomass and species diversity was least in talus and greatest in riverine grassland. Communities in talus and thicket were most similar and those in riverine grassland and thicket least similar. In general, these results suggest that woodland‐savannah communities are highly variable and appear to be resource‐limited.

Small mammals of a woodland‐savannah ecosystem in Zimbabwe. I. Density and habitat occupancy patterns

Population and habitat occupancy patterns of small mammals in five woodland‐savannah habitats (riverine grassland, miombo, mopane, talus, thicket) were studied at Sengwa Wildlife Research Area in Zimbabwe between July 1992 and July 1993. The study was initiated following a drought year and extended over a year of average rainfall. Fourteen species of small mammals were recorded during mark‐and‐recapture live‐trapping. Populations of most species were low during the 1992 cool dry and hot dry seasons, began increasing during the hot wet season, and attained peak densities during the 1993 cool dry season. The greatest amplitudes of density fluctuations were exhibited by the bush squirrel (Paraxerus cepapi) and the multimammate mouse (Mastomys natalensis). The numbers of habitats occupied by a single species ranged from one to four, although the majority of captures for each species tended to occur in a single habitat. The habitats occupied by an individual species during the season of lowest density was always the same as the one in which it reached its highest density. Temporal variation in density was greatest in riverine grassland and least in talus. Overall low densities during this study may have resulted from a combination of drought and impacts of large mammals on small mammal habitats.

High-Altitude Pursuit of Insects by Echolocating Bats

Bat detectors on helium-filled kite balloons revealed echolocating bats active at altitudes ≤ 600 m above the ground over Brachystegia woodland in the Sengwa Wildlife Research Area, Zimbabwe. Feeding buzzes indicated that bats were actively foraging to 600 m. At least seven species of bats were detected, including six molossids and one emballonurid.