Suchergebnisse

Context
Managed wild lions (Panthera leo) are lions found in smaller (<1000 km2), fenced protected areas that hold a substantial portion of South Africa's wild lion population. Because the natural population control mechanisms are compromised within these properties, managers must actively control population growth rates. Fecundity control is used by wildlife managers, but long-term, empirical data on the impact and consequences of such interventions in lions are lacking.


Aims
The aim of the present study was to assess the effectiveness of two methods of contraception (deslorelin implant and unilateral hysterectomy) in reducing cub recruitment of managed wild lions.

Methods
Survey data spanning 14 years from 94 managed wild lions on 19 protected areas were used to evaluate the effectiveness of deslorelin implant treatments and unilateral hysterectomies on population growth rates through mimicking open system cub recruitment.

Key results
Deslorelin implants were effective at increasing the age of first reproduction and lengthening inter-birth intervals. There was also an unexpected decrease in litter size. Behavioural side-effects were recorded in 40% of individuals: 19% pride fragmentation; 13% lack of receptiveness towards males; 8% other. The more successive deslorelin implants a lioness had, the more likely it was that weight gain was reported. Unilateral hysterectomy resulted in a decrease in litter size post-surgery, but this was not statistically significant. No behavioural or physiological side-effects were noted after unilateral hysterectomy.

Conclusions
Deslorelin treatment was more effective in reducing the reproductive output of managed wild lionesses than unilateral hysterectomy surgery. While more side-effects were associated with deslorelin implants than unilateral hysterectomies, a single deslorelin treatment is currently a good option for fecundity reduction. More research is required on unilateral hysterectomy surgery.

Implications
Neither deslorelin implants nor unilateral hysterectomies offer a 'silver bullet' solution for reducing rapid population growth in managed wild lions. Reproductive control should be integrated with other best-practice approaches.

Despite being heavily exploited, pangolins (Pholidota: Manidae) have been subject to limited research, resulting in a lack of reliable population estimates and standardised survey methods for the eight extant species. Camera trapping represents a unique opportunity for broad-scale collaborative species monitoring due to its largely nondiscriminatory nature, which creates considerable volumes of data on a relatively wide range of species. This has the potential to shed light on the ecology of rare, cryptic and understudied taxa, with implications for conservation decision-making. We undertook a global analysis of available pangolin data from camera trapping studies across their range in Africa and Asia. Our aims were (1) to assess the utility of existing camera trapping efforts as a method for monitoring pangolin populations, and (2) to gain insights into the distribution and ecology of pangolins. We analysed data collated from 103 camera trap surveys undertaken across 22 countries that fell within the range of seven of the eight pangolin species, which yielded more than half a million trap nights and 888 pangolin encounters. We ran occupancy analyses on three species (Sunda pangolin Manis javanica, white-bellied pangolin Phataginus tricuspis and giant pangolin Smutsia gigantea). Detection probabilities varied with forest cover and levels of human influence for P. tricuspis, but were low (<0.05) for all species. Occupancy was associated with distance from rivers for M. javanica and S. gigantea, elevation for P. tricuspis and S. gigantea, forest cover for P. tricuspis and protected area status for M. javanica and P. tricuspis. We conclude that camera traps are suitable for the detection of pangolins and large-scale assessment of their distributions. However, the trapping effort required to monitor populations at any given study site using existing methods appears prohibitively high. This may change in the future should anticipated technological and methodological advances in camera trapping facilitate greater sampling efforts and/or higher probabilities of detection. In particular, targeted camera placement for pangolins is likely to make pangolin monitoring more feasible with moderate sampling efforts. (c) 2019 The Authors. Published by Elsevier B.V. ; Fondation Segr~e; Biodiversity Monitoring Centre (Centre de Surveillance de la Biodiversit ~e) at the Faculty of Sciences of the University of Kisangani; Centre for International Forestry Research (CIFOR); Department of Science and Technology, Government of India (DST)Department of Science & Technology (India) [SR/S0/AS-100/2007]; Ministry of Education MalaysiaMinistry of Education, Malaysia [NRGS 2013/1088/02]; U.S. National Science FoundationNational Science Foundation (NSF) [BCS 1266389]; AXA Research Fellowship; Gordon and Betty Moore FoundationGordon and Betty Moore Foundation ; Thank you to the many individuals and institutions who generously made their data available for this study, and to the Zoological Society of London and donors to the IUCN SSC Pangolin Specialist Group for supporting the time of HK and CB during their research internships. The authors are grateful to Fondation Segr~e for supporting this research. AL would like to thank the Biodiversity Monitoring Centre (Centre de Surveillance de la Biodiversit ~e) at the Faculty of Sciences of the University of Kisangani and the Centre for International Forestry Research (CIFOR) for financial, academic and logistical support. AM would like to thank Agence Nationale des Parcs Nationaux and Centre National de la Recherche Scientifique et Technologique for kindly granting permission to conduct research in Gabon. CKO and TB would like to thank the Nouabal~e-Ndoki Foundation and Ministry of Forest Economy, Republic of Congo for kindly providing research permissions. GVG would like to gratefully thank the Department of Science and Technology, Government of India for their funding (DST. No. SR/S0/AS-100/2007), Mr. K. M. Selvan and Mr. S. Lyngdoh for their support in field data collection, and the Department of Environment & Forest, Government of Arunachal Pradesh for permissions. JAMwas supported by Ministry of Education Malaysia (NRGS 2013/1088/02). LAI acknowledges support from the U.S. National Science Foundation (BCS 1266389). ORW was supported by an AXA Research Fellowship. SE would like to thank R. Mueller and R. Roder for their input into data processing. Some data in this publication was provided by the Tropical Ecology Assessment and Monitoring (TEAM) Network, a collaboration between Conservation International, the Smithsonian Institution, and the Wildlife Conservation Society, and partially funded by these institutions, the Gordon and Betty Moore Foundation, and other donors.