Cross-scale and social-ecological changes constitute main threats to private land conservation in South Africa.

Conserving biodiversity in the long term will depend in part on the capacity of Protected Areas (PAs) to cope with cross-scale, social-ecological disturbances and changes, which are becoming more frequent in a highly connected world. Direct threats to biodiversity within PAs and their interactions with broader-scale threats are both likely to vary with PA spatial and management characteristics (e.g., location, dependence on ecotourism revenues, governmental support). Private Land Conservation Areas (PLCAs) are interesting case study systems for assessing cross-scale threats to PAs and their determinants. Despite the growing number of PLCAs around the world, there is considerable uncertainty regarding the long-term capacity of these privately owned areas to conserve biodiversity. Their potential impermanence is commonly raised as a key concern. To better understand the threats to which different types of PLCAs are likely to be vulnerable, we asked 112 PLCA landholders in South Africa what they perceived as the top threats to their PLCAs. Landowners identified direct threats to the biodiversity within their PLCAs (e.g., poaching, extreme weather, inappropriate fire regimes, alien species) as well as describing broader socio-economic threats (e.g., regional crime, national legislation and politics, global economic recessions), which were noted to interact across scales. We found support for the hypothesis that patterns in the perceived multi-scale threats to a PLCA correspond with its management and spatial characteristics, including its remoteness, dependence on ecotourism or hunting revenues, and richness of megafaunal species. Understanding the threats to which different PLCAs may be vulnerable is useful for developing more nuanced, targeted strategies to build PLCA resilience to these threats (for example, by strengthening the capacity of self-funded PLCAs to cope with the threat of economic downturns through more innovative financial instruments or diversified revenue streams). Our findings highlight the importance of considering interactions between broad-scale socio-economic changes and direct threats to biodiversity, which can influence the resilience of PAs in ways that are not anticipated by more traditional, discipline-specific consideration of direct threats to the biodiversity within their boundaries.

Traps and transformations influencing the financial viability of tourism on private-land conservation areas.

The ability of private conservation organizations to remain financially viable is a key factor influencing their effectiveness. One-third of financially motivated private-land conservation areas (PLCAs) surveyed in South Africa are unprofitable, raising questions about landowners' abilities to effectively adapt their business models to the socioeconomic environment. In any complex system, options for later adaptation can be constrained by starting conditions (path dependence). We tested 3 hypothesized drivers of path dependence in PLCA ecotourism and hunting business models: (H1) the initial size of a PLCA limits the number of mammalian game and thereby predators that can be sustained; (H2) initial investments in infrastructure limit the ability to introduce predators; and (H3) rainfall limits game and predator abundance. We further assessed how managing for financial stability (optimized game stocking) or ecological sustainability (allowing game to fluctuate with environmental conditions) influenced the ability to overcome path dependence. A mechanistic PLCA model based on simple ecological and financial rules was run for different initial conditions and management strategies, simulating landowner options for adapting their business model annually. Despite attempts by simulated landowners to increase profits, adopted business models after 13 years were differentiated by initial land and infrastructural assets, supporting H1 and H2. A conservation organization's initial assets can cause it to become locked into a financially vulnerable business model. In our 50-year simulation, path dependence was overcome by fewer of the landowners who facilitated natural ecological variability than those who maintained constant hunting rates and predator numbers, but the latter experienced unsustainably high game densities in low rainfall years. Management for natural variability supported long-term ecological sustainability but not shorter term socioeconomic sustainability for PLCAs. Our findings highlight trade-offs between ecological and economic sustainability and suggest a role for governmental support of the private conservation industry.

Positives and pathologies of natural resource management on private land-conservation areas.

In managed natural resource systems, such as fisheries and rangelands, there is a recognized trade-off between managing for short-term benefits and managing for longer term resilience. Management actions that stabilize ecological attributes or processes can improve productivity in the supply of ecosystem goods and services in the short term but erode system resilience at longer time scales. For example, fire suppression in rangelands can increase grass biomass initially but ultimately result in an undesirable, shrub-dominated system. Analyses of this phenomenon have focused largely on how management actions influence slow-changing biophysical system attributes (such as vegetation composition). Data on the frequency of management actions that reduce natural ecological variation on 66 private land-conservation areas (PLCAs) in South Africa were used to investigate how management actions are influenced by manager decision-making approaches, a largely ignored part of the problem. The pathology of natural resource management was evident on some PLCAs: increased focus on revenue-generation in decision making resulted in an increased frequency of actions to stabilize short-term variation in large mammal populations, which led to increased revenues from ecotourism or hunting. On many PLCAs, these management actions corresponded with a reduced focus on ecological monitoring and an increase in overstocking of game (i.e., ungulate species) and stocking of extralimitals (i.e., game species outside their historical range). Positives in natural resource management also existed. Some managers monitored slower changing ecological attributes, which resulted in less-intensive management, fewer extralimital species, and lower stocking rates. Our unique, empirical investigation of monitoring-management relationships illustrates that management decisions informed by revenue monitoring versus ecological monitoring can have opposing consequences for natural resource productivity and sustainability. Promoting management actions that maintain resilience in natural resource systems therefore requires cognizance of why managers act the way they do and how these actions can gradually shift managers toward unsustainable strategies.

The bii4africa dataset of faunal and floral population intactness estimates across Africa's major land uses.

Sub-Saharan Africa is under-represented in global biodiversity datasets, particularly regarding the impact of land use on species' population abundances. Drawing on recent advances in expert elicitation to ensure data consistency, 200 experts were convened using a modified-Delphi process to estimate 'intactness scores': the remaining proportion of an 'intact' reference population of a species group in a particular land use, on a scale from 0 (no remaining individuals) to 1 (same abundance as the reference) and, in rare cases, to 2 (populations that thrive in human-modified landscapes). The resulting bii4africa dataset contains intactness scores representing terrestrial vertebrates (tetrapods: ±5,400 amphibians, reptiles, birds, mammals) and vascular plants (±45,000 forbs, graminoids, trees, shrubs) in sub-Saharan Africa across the region's major land uses (urban, cropland, rangeland, plantation, protected, etc.) and intensities (e.g., large-scale vs smallholder cropland). This dataset was co-produced as part of the Biodiversity Intactness Index for Africa Project. Additional uses include assessing ecosystem condition; rectifying geographic/taxonomic biases in global biodiversity indicators and maps; and informing the Red List of Ecosystems.

An objective approach to determining the weight ranges of prey preferred by and accessible to the five large African carnivores.

Broad-scale models describing predator prey preferences serve as useful departure points for understanding predator-prey interactions at finer scales. Previous analyses used a subjective approach to identify prey weight preferences of the five large African carnivores, hence their accuracy is questionable. This study uses a segmented model of prey weight versus prey preference to objectively quantify the prey weight preferences of the five large African carnivores. Based on simulations of known predator prey preference, for prey species sample sizes above 32 the segmented model approach detects up to four known changes in prey weight preference (represented by model break-points) with high rates of detection (75% to 100% of simulations, depending on number of break-points) and accuracy (within 1.3±4.0 to 2.7±4.4 of known break-point). When applied to the five large African carnivores, using carnivore diet information from across Africa, the model detected weight ranges of prey that are preferred, killed relative to their abundance, and avoided by each carnivore. Prey in the weight ranges preferred and killed relative to their abundance are together termed "accessible prey". Accessible prey weight ranges were found to be 14-135 kg for cheetah Acinonyx jubatus, 1-45 kg for leopard Panthera pardus, 32-632 kg for lion Panthera leo, 15-1600 kg for spotted hyaena Crocuta crocuta and 10-289 kg for wild dog Lycaon pictus. An assessment of carnivore diets throughout Africa found these accessible prey weight ranges include 88±2% (cheetah), 82±3% (leopard), 81±2% (lion), 97±2% (spotted hyaena) and 96±2% (wild dog) of kills. These descriptions of prey weight preferences therefore contribute to our understanding of the diet spectrum of the five large African carnivores. Where datasets meet the minimum sample size requirements, the segmented model approach provides a means of determining, and comparing, the prey weight range preferences of any carnivore species.