Peter J. Mundy

Factors influencing long-term and seasonal waterbird abundance and composition at two adjacent lakes in Zimbabwe

The spatial and temporal structures of waterbird communities are dynamic and complex with many driving factors. We used long-term waterbird census data at two lakes in Zimbabwe to explore the ecological and anthropogenic drivers of waterbird community composition and abundance. Ecological drivers predicted to influence waterbird communities include rainfall quantity and distribution, waterbird movement, breeding and moulting; anthropogenic drivers include activities such as fishing and agriculture. Results suggest that seasonal variations in resource availability influenced the waterbird community composition and abundance, as did movements at local, regional, and intercontinental scales. Bird numbers in the two perennial lakes experienced large changes in structure during two droughts. We also used the study as a baseline for considering the risk of spread of avian influenza virus (AIV) spread in waterbird communities in Zimbabwean lakes, which is likely to be higher in dry seasons and during drought years when waterbird abundance is high. Our study emphasises the importance of long-term ecological data in understanding crucial aspects of biodiversity conservation as well as pathogen dynamics in wild waterbird communities, with important management implications.

Patterns of mistletoe infection in four Acacia species in a semi-arid southern African savanna

In a range of systems, studies on mistletoe distribution on the host plant have documented a number of factors that affect their occurrence and spread (Aukema & Martinez del Rio 2002a, Bowie & Ward 2004, Overton 1996, Reid et al . 1995). These patterns can be determined by host specificity, environmental conditions, host plant characteristics (Martinez del Rio et al . 1995) and the movement patterns of dispersal agents (Aukema & Martinez del Rio 2002a, 2002b). In mistletoe plants, host choice can be considerably influenced by the advantages of interacting with relatively abundant hosts (Norton & Carpenter 1998, Norton & De Lange 1999). Besides the relative abundance of host species, characteristics such as branch size, age and height can have a strong effect on mistletoe attachment resulting in size-related mistletoe infection patterns (Overton 1994). Generally positive relationships between mistletoe infection and host size have been demonstrated worldwide (Donohue 1995, Martinez del Rio et al . 1996, Norton et al . 1997, Reid & Stafford Smith 2000) and they have been interpreted in terms of the preferences by dispersing birds to perch and feed in taller trees (Aukema & Martinez del Rio 2002a) and trees accumulating infections as they age (Overton 1994). Aukema & Martinez del Rio (2002a) reported more frequent perching in taller-than-average trees by the phainopepla ( Phainopepla nitens ), which is the principal disperser of the desert mistletoe Phoradendron californicum . Thus, visits by mistletoe-seed-dispersing birds, and therefore mistletoe seeds received, tend to increase with tree height (Aukema & Martinez del Rio 2002a). Using a simple metapopulation model, Overton (1994) predicted the frequency of parasitized trees to increase with host age. Therefore, assuming that size is a good proxy for age, large trees are likely to be more infected than smaller trees. Reid & Stafford Smith (2000), using experimentally disinfected trees, found that larger trees were disproportionately re-infected with mistletoes. This size–intensity relationship may be used to describe mistletoe infection patterns. However, several previous studies have shown size–intensity relationships to be weak (Aukema & Martinez del Rio 2002a, Donohue 1995, Overton 1994, Reid & Stafford Smith 2000). This indicates that other factors may be important in determining mistletoe infection intensity, including that already parasitized hosts of a specific height are more likely to receive seeds than non-parasitized hosts of the same height or dispersers are likely to be attracted to trees for reasons other than size (Aukema & Martinez del Rio 2002a).

Flight behavioural responses to sport hunting by two African herbivores

Sport hunting may have severe behavioural consequences, and possibly conservation implications for wildlife populations. We used flight initiation distances by two herbivores, impala (Aepyceros melampus) and greater kudu (Tragelaphus strepsiceros) to assess the impacts of sport hunting on their flight behaviour. We compared Gwaai, a designated hunting area adjacent to Hwange National Park, a protected area in Zimbabwe.We aimed to estimate flight initiation distances (FIDs) for impala and kudu as this can be a good measure of hunting effect on behaviour. Our results suggest that impala and kudu are more flight prone in hunting areas than in non-hunting areas. We propose habituation to explain the shorter FIDs in the protected area,and the risk of being shot by hunters the higher FIDs in the hunting area.We concede that more field observations are needed to estimate the distance at which animals will always trigger an immediate flight response from approaching predators (Dmin) and the distance above which prey will not move away from an approaching predator as it is not perceived to be dangerous (Dmax) in our study area. However,we suggest that Dmin is a useful index for wildlife managers to assess predation risk.

Using Africa's protected area network to estimate the global population of a threatened and declining species: a case study of the Critically Endangered White‐headed Vulture Trigonoceps occipitalis

Abstract The White‐headed Vulture Trigonoceps occipitalis (WhV) is uncommon and largely restricted to protected areas across its range in sub‐Saharan Africa. We used the World Database on Protected Areas to identify protected areas (PAs) likely to contain White‐headed Vultures. Vulture occurrence on road transects in Southern, East, and West Africa was adjusted to nests per km2 using data from areas with known numbers of nests and corresponding road transect data. Nest density was used to calculate the number of WhV nests within identified PAs and from there extrapolated to estimate the global population. Across a fragmented range, 400 PAs are estimated to contain 1893 WhV nests. Eastern Africa is estimated to contain 721 nests, Central Africa 548 nests, Southern Africa 468 nests, and West Africa 156 nests. Including immature and nonbreeding birds, and accounting for data deficient PAs, the estimated global population is 5475 ‐ 5493 birds. The identified distribution highlights are alarming: over 78% (n = 313) of identified PAs contain fewer than five nests. A further 17% (n = 68) of PAs contain 5 ‐ 20 nests and 4% (n = 14) of identified PAs are estimated to contain >20 nests. Just 1% (n = 5) of PAs are estimated to contain >40 nests; none is located in West Africa. Whilst ranging behavior of WhVs is currently unknown, 35% of PAs large enough to hold >20 nests are isolated by more than 100 km from other PAs. Spatially discrete and unpredictable mortality events such as poisoning pose major threats to small localized vulture populations and will accelerate ongoing local extinctions. Apart from reducing the threat of poisoning events, conservation actions promoting linkages between protected areas should be pursued. Identifying potential areas for assisted re‐establishment via translocation offers the potential to expand the range of this species and alleviate risk.

Morphometrics of White-browed Sparrow-Weavers Plocepasser mahali in south-western Zimbabwe

This paper describes size and body condition of individuals in a population of the cooperatively breeding White-browed Sparrow-Weaver Plocepasser mahali in south-western Zimbabwe in relation to the birds’ social status within their colony. We undertook measurements and observations of colour-ringed individuals during two successive breeding seasons. Each colony was organised into a dominance hierarchy, with a single dominant breeding pair and male and female subordinates. Our results showed that males were generally larger than females in body mass, wing and bill length. Within each sex size was not significantly related to dominance status. Body condition did not vary by sex, age or status.

Impala, Aepyceros melampus: does browse quality influence their use of sites originally utilised as short-duration kraals in a southern African savanna?

In eastern and southern Africa, some ranch owners are now keeping cattle overnight in temporary corrals (hereafter referred to as kraals) within rangelands for short durations to improve grass production. However, this has profound effects on the woody plant community. For instance, cattle break woody plant stems and strip them of foliage, initiating resprouting. The resprouts produced have high foliar nitrogen (N) and reduced condensed tannin (CT) concentrations, making them attractive to herbivores. The aim of this study was to determine the key nutrient-quality parameters of resprouts that make previously kraaled sites attractive to impala soon after cattle removal at Debshan Ranch in central Zimbabwe. We determined resprout length, foliar N, phosphorus (P), potassium, CT, fibre and rumen fermentation of three browse species, viz. Grewia monticola Sond., Terminalia sericea Burch. ex DC. and Dichrostachys cinerea (L.) Wight and Arn., and related them to impala use of previously kraaled sites. We used impala dung density to determine the use patterns of previously kraaled sites 2, 4, 12 and 24 weeks after cattle removal and compared them with the surrounding vegetation. Impala use of previously kraaled sites was highest 4 weeks after cattle removal and lowest in the surrounding vegetation. Resprout length increments were 6-fold over a 10-week growth period in all three woody species. Foliar N and P were generally higher, whereas CT was lower, in previously kraaled sites than the surrounding vegetation in all three of the plant browse species. Impala use of previously kraaled sites showed a strong negative relationship with foliar CT. We conclude that kraaling initiates strong resprout responses by woody plants soon after cattle removal, to produce resprouts of high nutrient quality, which attract herbivores such as impala.

Fluctuations in bush and rock hyrax (Hyracoidea: Procaviidae) abundances over a 13-year period in the Matopos, Zimbabwe

Bush (Heterohyrax brucei) and rock (Procavia capensis) hyraxes (Hyracoidea: Procaviidae) are abundant small mammals and important prey for vertebrate carnivores in the Rhodes Matopos National Park (RMNP), southwestern Zimbabwe. We monitored hyraxes at 20 observation stations in the 424 km2 RMNP over a 13-year period (1993–2005). We identified hyraxes to species, and counted and aged them. From yearly counts and age distributions, we computed an index of relative abundance (AI - individuals/km2) and estimate of productivity (proportion of the sample comprising juveniles) for each species. Time series analysis showed that annual fluctuations in AI were marked, but not cyclic, with ranges of 0.4–113.8% (median = 30.0%) for Heterohyrax brucei and 3.7–64.7% (median = 11.0%) for Procavia capensis. Cross-correlation function revealed interspecific synchrony in annual fluctuation in numbers of individuals of the two species. A positive relationship existed between AI of H. brucei and rainfall of the previous austral summer, suggesting that annual precipitation contributes to fluctuations in abundance of this species; synchronous fluctuation of the two species suggests a common response to other regulating factors. Additional abiotic and biotic processes that potentially affected populations of both species are chronicled.

The African elephant - : something to cherish and to use

The African savannah (bush) elephant Loxodonta africana is a wonderful animal, yet at the same time it is a problem both to the environment and to rural people. Aspects of its biology are listed, and its valuable products are noted. These latter are its ecotourism potential, its trophy (some spectacular tusks are tabulated), the ivory itself, skin, curios, and meat. The ‘elephant problem’ became apparent in Africa in the early 1960s: the bulls in particular can severely damage trees, and this effect is seen from an elephant density of 0.5 per sq. km. Throughout Africa, with the exception of southern Africa, poaching has been rampant and has culled the populations. Management aspects, such as legal culling, are considered. Ecotourism dollars should be re‐invested in the resource, and sustainable use of the animal should be the governing idea.

Integrating Local Ecological Knowledge for Waterbird Conservation: Insights From Kavango-Zambezi Transfrontier Conservation Area, Zimbabwe

Weaving local and scientific knowledge systems is important to enhance understanding, practice, and ethics toward natural resources sustainable utilization. We focused on wetlands and waterbirds and used local knowledge and perceptions by key informants in and around a protected area in Zimbabwe to investigate (a) trends in rainfall and water quality, (b) waterbird trends and associated uses, and (c) drivers, mechanisms, and impacts behind waterbird trends, to understand waterbird ecological dynamics. We confronted these perceptions to available data locally and globally. Furthermore, we explored local ideas to improve waterbird survival. Associations between informant variables and trends in water quality were tested using the χ2 test while multiple correspondence analyses were used to explore drivers, mechanisms, and impacts of bird trends. Wildfowl were cited the most (48.7% of all citations), probably linked to their use as food, and they were negatively driven by human predation but would increase when left to follow natural processes. Changes in natural processes and wetlands drove large piscivores into decline, but their populations would increase when predation was controlled. Generalist species responded positively when climate and resources were not limiting. We then discus the feasibility of the suggested waterbird conservation remedies: education, increasing surface water, law enforcement, sustainable use guidelines, and modified drinking troughs for large herbivores. Local knowledge and available local trends data were inconsistent with International Union for the Conservation of Nature trend status. The local sources of knowledge were not correlated but broadly consistent. We also discuss the scale discrepancies and how the sources of information can be complementary.