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- Patterns and Drivers of Rodent Abundance across a South African Multi-Use LandscapePublication . C. Afonso, Beatriz; Swanepoel, Lourens H.; Rosa, Beatriz; Marques, Tiago A.; Rosalino, L. M.; Santos-Reis, Margarida; Curveira-Santos, GonçaloSouth Africa’s decentralized approach to conservation entails that wildlife outside formally protected areas inhabit complex multi-use landscapes, where private wildlife business (ecotourism and/or hunting) co-exist in a human-dominated landscape matrix. Under decentralized conservation, wildlife is perceived to benefit from increased amount of available habitat, however it is crucial to understand how distinct management priorities and associated landscape modifications impact noncharismatic taxa, such as small mammals. We conducted extensive ink-tracking-tunnel surveys to estimate heterogeneity in rodent distribution and investigate the effect of different environmental factors on abundance patterns of two size-based rodent groups (small- and medium-sized species), across three adjacent management contexts in NE KwaZulu-Natal, South Africa: a private ecotourism game reserve, mixed farms and traditional communal areas (consisting of small clusters of houses interspersed with grazing areas and seminatural vegetation). Our hypotheses were formulated regarding the (1) area typology, (2) vegetation structure, (3) ungulate pressure and (4) human disturbance. Using a boosted-regression-tree approach, we found considerable differences between rodent groups’ abundance and distribution, and the underlying environmental factors. The mean relative abundance of medium-sized species did not differ across the three management contexts, but small species mean relative abundance was higher in the game reserves, confirming an influence of the area typology on their abundance. Variation in rodent relative abundance was negatively correlated with human disturbance and ungulate presence. Rodent abundance seems to be influenced by environmental gradients that are directly linked to varying management priorities across land uses, meaning that these communities might not benefit uniformly by the increased amount of habitat promoted by the commercial wildlife industry.
- Mesocarnivore community structuring in the presence of Africa's apex predatorPublication . Curveira-Santos, Gonçalo; Sutherland, Chris; Tenan, Simone; Fernández-Chacón, Albert; Mann, Gareth K. H.; Pitman, Ross T.; Swanepoel, Lourens H.Apex predator reintroductions have proliferated across southern Africa, yet their ecological effects and proposed umbrella benefits of associated management lack empirical evaluations. Despite a rich theory on top-down ecosystem regulation via mesopredator suppression, a knowledge gap exists relating to the influence of lions (Panthera leo) over Africa's diverse mesocarnivore (less than 20 kg) communities. We investigate how geographical variation in mesocarnivore community richness and occupancy across South African reserves is associated with the presence of lions. An interesting duality emerged: lion reserves held more mesocarnivore-rich communities, yet mesocarnivore occupancy rates and evenness-weighted diversity were lower in the presence of lions. Human population density in the reserve surroundings had a similarly ubiquitous negative effect on mesocarnivore occupancy. The positive association between species richness and lion presence corroborated the umbrella species concept but translated into small differences in community size. Distributional contractions of mesocarnivore species within lion reserves, and potentially corresponding numerical reductions, suggest within-community mesopredator suppression by lions, probably as a result of lethal encounters and responses to a landscape of fear. Our findings offer empirical support for the theoretical understanding of processes underpinning carnivore community assembly and are of conservation relevance under current large-predator orientated management and conservation paradigms.
- Responses of carnivore assemblages to decentralized conservation approaches in a South African landscapePublication . Curveira-Santos, Gonçalo; Sutherland, Chris; Santos-Reis, Margarida; Swanepoel, Lourens H.1. Conservation efforts in South Africa play out across multi-use landscapes where formal protected areas coexist with private wildlife business (ecotourism and/or hunting) in a human-dominated matrix. Despite the persistence of highly diverse carnivore guilds, management idiosyncrasies are often orientated towards charismatic large predators and assemblage-level patterns remain largely unexplored. 2. We conducted an extensive camera-trap survey in a natural quasi-experimental setting in KwaZulu-Natal, South Africa. We sampled across a protection gradient characterized by a provincial protected area (highest and formal protection status), a private ecotourism reserve, game ranches and traditional communal areas (lowest protected status). We evaluated assemblage-level and species-specific responses of free-ranging carnivores to the varying management contexts and associated environmental gradients. 3. Despite similar assemblage composition between management contexts, sitescale carnivore richness and occupancy rates were greater in the formal protected area than adjacent private reserve and game ranches. Carnivore occupancy was more similar between these private wildlife areas, although putative problem species were more common in the private reserve, and contrasted with depauperate assemblages in least protected communal lands. Variation in carnivore occupancy probabilities was largely driven by land use contexts, that is, the level and nature of protection, relative to underlying fine-scale landscape attributes (e.g. distance to conservation fences) or apex predator populations. 4. Synthesis and applications. Our findings provide convincing empirical support for the added value of multi-tenure conservation estates augmenting and connecting South Africa's protected areas. However, our emphasis on free-ranging carnivores exemplifies the importance of maintaining areas under long-term formal protection and the risks with viewing lucrative wildlife business as a conservation panacea. We suggest that unmanaged carnivore species be the formal components of carnivore reintroduction and recovery programmes to better gauge the complementary conservation role of South Africa's private land.
- Global patterns of carnivore spatial ecology research in agroecosystemsPublication . Curveira-Santos, Gonçalo; Santos, Maria João; Santos-Reis, Margarida; Rosalino, L. M.The growing needs for agricultural expansion and intensification will likely continue to reduce and fragment the terrestrial habitats fundamental to mammalian carnivores. Recent research identified benefits of agroecosystems to carnivores recognizing their multifunctionality, mostly for common species. However, the variability of carnivore ecology investigated in agroecosystems, biases in agriculture types and species targeted, and methodological approaches may affect the available knowledge to reconcile conservation and agricultural production. To fill this gap, we conducted a systematic literature review to identify which aspects of and how is carnivore spatial ecology being investigated within agroecosystems. Of the 110 reviewed studies, most focused on agricultural crops (55%) and grasslands (47%) and half referred to monocultures. We found that 61% of the studies were conducted in Europe and North America. Eighty-four carnivore species were studied, 73% classified as Least Concern, with 67% of the studies targeting a single species and 30% focused on only seven common species. Almost all studies included some form of habitat use analysis and species’ home-range and its attributes (e.g. size, resource selection), the most common spatial ecology aspects studied. Most studies suggested that agriculture functions as food provisioning (69%) but few used direct food availability measures. Our results highlight that studies tend to be descriptive and geographically biased towards northern hemisphere and to non-forested agricultural types. We suggest that future carnivore spatial ecology research in agroecosystem should be hypotheses-driven, with greater focus on the mechanisms and processes through which agroecosystems might affect carnivore spatial ecology in particular for areas with high priority for carnivore conservation.
- Unravelling responses of carnivore assemblages to conservation and management models in South AfricaPublication . Curveira-Santos, Gonçalo; Santos-Reis, Margarida; Swanepoel, Lourens; Sutherland, ChrisAttempts to curtail ongoing biodiversity declines hinge on a deep understanding of wildlife responses to conservation efforts. South Africa’s diverse carnivore assemblages and local conservation setting exemplify the schism between community paradigms in contemporary ecology and species-centric management. A decentralized approach to conservation gave rise to complex and intensively managed multi-use landscapes, where formal protected areas coexist with the private commercial wildlife industry (ecotourism and hunting). Management idiosyncrasies are orientated towards economically valuable and charismatic species, including some large predators, while responses of most carnivore taxa remain overlooked. In this thesis, I explored the nature of assemblage-wide responses of South African carnivores to alternative conservation and management models, as possibly facilitated by varying intraguild dynamics. Using a combination of management-induced quasi-experiments and multi-species inference, I provide empirical support for: i) top-down suppression of mesocarnivore species acting in tandem with proposed conservation benefits of reintroduced apex predator populations; ii) the conservation value of areas under long-term formal protection for free-ranging carnivores, and the risks with viewing wildlife businesses as a conservation panacea; and iii) the need to consider intricate and context-dependent species interaction networks when evaluating the outcome of management options. Finally, I revisited carnivoran intraguild killing as a pervasive ecological mechanism underlying the structure of species-rich South African assemblages. Evidence for accentuated interspecific heterogeneity and varying intraguild dynamics weighed heavily in favor for the need to formally consider unmanaged species and guild processes in the development of carnivore conservation efforts and predator management plans. Collectively, my research suggests that broader biodiversity benefits of multi-tenure South African conservation landscapes are underpinned by unknown recovery trajectories of free-ranging species and unheeded ecological effects of management interventions via intraguild interactions. By further unravelling the complexity of South African carnivore assemblages my findings add to calls for a more holistic view of wildlife conservation management.