Evaluating connectivity models for conservation: insights from African lion dispersal patterns

Context Evaluating connectivity and identifying corridors for protection is a central challenge in applied ecology and conservation. Rigorous validation and comparison of how approaches perform in capturing biological processes is needed to guide research and conservation action. Objectives We aim to compare the ability of connectivity surfaces optimised using home range and dispersal data to accurately capture lion movement during dispersal, using cost-distance and circuit theory approaches. Methods We delineate periods of dispersal in African lions (Panthera leo) to obtain movement trajectories of dispersing individuals across the Kavango Zambezi Transfrontier Conservation Area, southern Africa. We use these trajectories to assess comparative measures of connectivity values at dispersal points across surfaces and the ability of models to discriminate between observed and randomised paths. Results Encouragingly, results show that on average, all connectivity approaches and resistance surfaces used perform well in predicting movements of an independent set of dispersing lions. Cost-distance approaches were generally more sensitive to resistance input than circuit theory, but differences in performance measures between resistance inputs were small across both approaches. Conclusions Findings suggest that home range data can be used to generate resistance surfaces for connectivity maps in this system, with independent dispersal data providing a promising approach to thresholding what is considered as “connected” when delineating corridors. Most dispersers traversed through landscapes that had minimal human settlement and are likely highly connected by dispersal. Research into limiting factors and dispersal abilities will be critical to understanding how populations will respond to increasing habitat fragmentation and human expansion

Behavioural adjustments of a large carnivore to access secondary prey in a human-dominated landscape

1. Conflict between people and large carnivores is an urgent conservation issue world-wide. Understanding the underlying ecological drivers of livestock depredation by large carnivores is greatly needed. 2. We studied the spatial, foraging and behavioural ecology of African lions Panthera leo in the Botswana Makgadikgadi ecosystem. This ecosystem comprises a protected area, characterized by high seasonal fluctuation in wild prey abundance, and adjacent lands, which are used for livestock grazing and characterized by stable livestock abundance, but also a risk of anthropogenic mortality. 3. Makgadikgadi lions preferentially preyed upon migratory wild herbivores when they were present; however, data from GPS (Global Positioning System) radiocollared lions revealed that the majority of the study lions did not follow the migratory herds but remained resident at one or other border of the park and switched to livestock (abundant and readily available), and to a lesser extent resident wild herbivores (relatively scarce), in periods of migratory wild herbivore scarcity. 4. Resident lions’ use of space differed between periods of wild prey abundance and scarcity. These changes were likely to increase the frequency of encounter with their primary prey in periods of primary prey abundance and with livestock in periods of primary prey scarcity. 5. The risk of conflict with humans was a major driver of lion ecology in the human-dominated landscape surrounding the protected area. Resident lions generally avoided the close vicinity of cattle- posts.When they used such areas, they avoided temporal overlap with periods that humans were most active and travelled at high speed reducing the time spent in these areas. 6. Synthesis and applications. This study suggests that lions balance the benefits of accessing livestock with the costs associated with livestock raiding. Hence, reduction in livestock availability through effective livestock husbandry in periods of wild prey scarcity should lead to reduced conflict.http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1365-2664ab201

Evidence of predation on aquatic vertebrates by serval in the Okavango Delta, Botswana

The serval (Leptailurus serval, Schreber 1776) occurs widely in sub‐Saharan Africa, though is absent from Congo Basin equatorial forest and from highly arid regions of North and South West of the continent. Preferred habitats include grassland and savannah woodland mosaics, frequently associated with rivers, wetlands and flood‐plains. The serval is a specialist rodentivore with rodents, particularly Murids, usually making up between 80% and 90% of their diet across much the species range. They also feed on shrews (Crocidura and Myosorex spp), small birds, amphibians, insects and small reptiles. There are occasional records of servals hunting young of small antelope, ground (Xerus spp) and tree squirrels (Paraxerus spp), larger ground and wading birds (e.g. flamingo, Phoeniconaias spp), hares (Lepus spp), springhares (Pedetes capensis), cane rats (Thryonomys spp), aquatic vertebrates and invertebrates and small carnivores. Grass culms, leaves and fruit are sometimes consumed. Here we present evidence of predation on larger aquatic vertebrates by serval in the Okavango Delta, Botswana.Robertson Foundationhttps://wileyonlinelibrary.com/journal/aje2021-12-31hj2021Mammal Research InstituteZoology and Entomolog

Food resource competition between African wild dogs and larger carnivores in an ecosystem with artificial water provision

Predators of similar size often compete over prey. In semi-arid ecosystems where water is a limiting resource, prey availability can be affected by water distribution, which further increases resource competition and exacerbate conflict among predators. This can have implications for carnivore dietary competition. Hence, we evaluated the dynamics of food resource competition between African wild dogs and four competing predators (cheetahs, leopards, lions and spotted hyaenas) in different seasons and across areas with different waterhole densities in Hwange National Park, Zimbabwe. We used the frequency of occurrence of prey items found in predators’ scats to analyse diet composition, overlap and prey preference. For most predators, kudu was most frequently consumed and preferred. Low and medium water-dependent prey (medium and small-sized) were mostly consumed by wild dogs, leopards and cheetahs. Wild dog diet overlap was high with all predators, particularly with hyaenas and lions. There were no seasonal differences in the predators diet. The diet overlap of wild dogs with lions was highest in the low waterhole density area, and wild dog diet composition did not differ significantly from the diet of lions and hyaenas. In the low waterhole density area, wild dogs and hyaenas broadened their niche breadth, and predators diet had a higher proportion of low water-dependent prey. A low density of waterholes increased food resource competition. However, high density of waterholes, where there is more prey availability, can increase the aggregation and density of predators, and hence, increase the risks involved in interspecific competition on wild dogs. To reduce food resource competition on wild dogs, we propose to conserve larger-bodied prey that are less dependent on water (e.g. kudu, reedbuck, eland, gemsbok). As the use of water pumping is common practice, we propose maintaining water management heterogeneity where prey which is less dependent on water can also thrive

Is there an elephant in the room? A Response to Batavia et al

Non peer reviewe

The Significance of African Lions for the Financial Viability of Trophy Hunting and the Maintenance of Wild Land

Recent studies indicate that trophy hunting is impacting negatively on some lion populations, notably in Tanzania. In 2004 there was a proposal to list lions on CITES Appendix I and in 2011 animal-welfare groups petitioned the United States government to list lions as endangered under their Endangered Species Act. Such listings would likely curtail the trophy hunting of lions by limiting the import of lion trophies. Concurrent efforts are underway to encourage the European Union to ban lion trophy imports. We assessed the significance of lions to the financial viability of trophy hunting across five countries to help determine the financial impact and advisability of the proposed trade restrictions. Lion hunts attract the highest mean prices (US$24,000–US$71,000) of all trophy species. Lions generate 5–17% of gross trophy hunting income on national levels, the proportional significance highest in Mozambique, Tanzania, and Zambia. If lion hunting was effectively precluded, trophy hunting could potentially become financially unviable across at least 59,538 km2 that could result in a concomitant loss of habitat. However, the loss of lion hunting could have other potentially broader negative impacts including reduction of competitiveness of wildlife-based land uses relative to ecologically unfavourable alternatives. Restrictions on lion hunting may also reduce tolerance for the species among communities where local people benefit from trophy hunting, and may reduce funds available for anti-poaching. If lion off-takes were reduced to recommended maximums (0.5/1000 km2), the loss of viability and reduction in profitability would be much lower than if lion hunting was stopped altogether (7,005 km2). We recommend that interventions focus on reducing off-takes to sustainable levels, implementing age-based regulations and improving governance of trophy hunting. Such measures could ensure sustainability, while retaining incentives for the conservation of lions and their habitat from hunting

Savanna fire management can generate enough carbon revenue to help restore Africa's rangelands and fill protected area funding gaps

Many savanna-dependent species in Africa including large herbivores and apex predators are at increasing risk of extinction. Achieving effective management of protected areas (PAs) in Africa where lions live will cost an estimated US$>1–2 billion/year in new funding. We explore the potential for fire-management-based carbon financing programs to fill this funding gap and benefit degrading savanna ecosystems. We demonstrate how introducing early dry season fire management programs could produce potential carbon revenues (PCRs) from either a single carbon financing method (avoided emissions) or from multiple sequestration methods ranging from US$ 59.6–655.9 million/year (at US$5/ton) or US$ 155.0 million/year to US$1.7 billion/year (at US$ 13/ton). We highlight variable but significant PCRs for savanna PAs from US$ 1.5–44.4 million/year per PA. We suggest investing in fire management programs to jump-start the United Nations Decade of Ecological Restoration to help restore degraded African savannas and conserve imperiled keystone herbivores and apex predators.https://www.cell.com/one-earth/homeam2022Zoology and Entomolog

Reclassification of the Specialized Metabolite Producer Pseudomonas mesoacidophila ATCC 31433 as a Member of the Burkholderia cepacia Complex.

Pseudomonas mesoacidophila ATCC 31433 is a Gram-negative bacterium, first isolated from Japanese soil samples, that produces the monobactam isosulfazecin and the β-lactam-potentiating bulgecins. To characterize the biosynthetic potential of P. mesoacidophila ATCC 31433, its complete genome was determined using single-molecule real-time DNA sequence analysis. The 7.8-Mb genome comprised four replicons, three chromosomal (each encoding rRNA) and one plasmid. Phylogenetic analysis demonstrated that P. mesoacidophila ATCC 31433 was misclassified at the time of its deposition and is a member of the Burkholderia cepacia complex, most closely related to Burkholderia ubonensis The sequenced genome shows considerable additional biosynthetic potential; known gene clusters for malleilactone, ornibactin, isosulfazecin, alkylhydroxyquinoline, and pyrrolnitrin biosynthesis and several uncharacterized biosynthetic gene clusters for polyketides, nonribosomal peptides, and other metabolites were identified. Furthermore, P. mesoacidophila ATCC 31433 harbors many genes associated with environmental resilience and antibiotic resistance and was resistant to a range of antibiotics and metal ions. In summary, this bioactive strain should be designated B. cepacia complex strain ATCC 31433, pending further detailed taxonomic characterization.IMPORTANCE This work reports the complete genome sequence of Pseudomonas mesoacidophila ATCC 31433, a known producer of bioactive compounds. Large numbers of both known and novel biosynthetic gene clusters were identified, indicating that P. mesoacidophila ATCC 31433 is an untapped resource for discovery of novel bioactive compounds. Phylogenetic analysis demonstrated that P. mesoacidophila ATCC 31433 is in fact a member of the Burkholderia cepacia complex, most closely related to the species Burkholderia ubonensis Further investigation of the classification and biosynthetic potential of P. mesoacidophila ATCC 31433 is warranted

TCR‐induced alteration of primary MHC peptide anchor residue

The HLA‐A*02:01‐restricted decapeptide EAAGIGILTV, derived from melanoma antigen recognized by T‐cells‐1 (MART‐1) protein, represents one of the best‐studied tumor associated T‐cell epitopes, but clinical results targeting this peptide have been disappointing. This limitation may reflect the dominance of the nonapeptide, AAGIGILTV, at the melanoma cell surface. The decapeptide and nonapeptide are presented in distinct conformations by HLA‐A*02:01 and TCRs from clinically relevant T‐cell clones recognize the nonapeptide poorly. Here, we studied the MEL5 TCR that potently recognizes the nonapeptide. The structure of the MEL5‐HLA‐A*02:01‐AAGIGILTV complex revealed an induced fit mechanism of antigen recognition involving altered peptide–MHC anchoring. This “flexing” at the TCR–peptide–MHC interface to accommodate the peptide antigen explains previously observed incongruences in this well‐studied system and has important implications for future therapeutic approaches. Finally, this study expands upon the mechanisms by which molecular plasticity can influence antigen recognition by T cells