1
|
Creel S, Reyes de Merkle J, Goodheart B, Mweetwa T, Mwape H, Simpamba T, Becker MS. An integrated population model reveals source-sink dynamics for competitively subordinate African wild dogs linked to anthropogenic prey depletion. J Anim Ecol 2024; 93:417-427. [PMID: 38311822 DOI: 10.1111/1365-2656.14052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Accepted: 01/04/2024] [Indexed: 02/06/2024]
Abstract
Many African large carnivore populations are declining due to decline of the herbivore populations on which they depend. The densities of apex carnivores like the lion and spotted hyena correlate strongly with prey density, but competitively subordinate carnivores like the African wild dog benefit from competitive release when the density of apex carnivores is low, so the expected effect of a simultaneous decrease in resources and dominant competitors is not obvious. Wild dogs in Zambia's South Luangwa Valley Ecosystem occupy four ecologically similar areas with well-described differences in the densities of prey and dominant competitors due to spatial variation in illegal offtake. We used long-term monitoring data to fit a Bayesian integrated population model (IPM) of the demography and dynamics of wild dogs in these four regions. The IPM used Leslie projection to link a Cormack-Jolly-Seber model of area-specific survival (allowing for individual heterogeneity in detection), a zero-inflated Poisson model of area-specific fecundity and a state-space model of population size that used estimates from a closed mark-capture model as the counts from which (latent) population size was estimated. The IPM showed that both survival and reproduction were lowest in the region with the lowest density of preferred prey (puku, Kobus vardonii and impala, Aepyceros melampus), despite little use of this area by lions. Survival and reproduction were highest in the region with the highest prey density and intermediate in the two regions with intermediate prey density. The population growth rate (λ ) was positive for the population as a whole, strongly positive in the region with the highest prey density and strongly negative in the region with the lowest prey density. It has long been thought that the benefits of competitive release protect African wild dogs from the costs of low prey density. Our results show that the costs of prey depletion overwhelm the benefits of competitive release and cause local population decline where anthropogenic prey depletion is strong. Because competition is important in many guilds and humans are affecting resources of many types, it is likely that similarly fundamental shifts in population limitation are arising in many systems.
Collapse
Affiliation(s)
- Scott Creel
- Department of Ecology, Montana State University, Bozeman, Montana, USA
- Zambian Carnivore Programme, Mfuwe, Eastern Province, Zambia
| | - Johnathan Reyes de Merkle
- Department of Ecology, Montana State University, Bozeman, Montana, USA
- Zambian Carnivore Programme, Mfuwe, Eastern Province, Zambia
| | - Ben Goodheart
- Department of Ecology, Montana State University, Bozeman, Montana, USA
- Zambian Carnivore Programme, Mfuwe, Eastern Province, Zambia
| | | | - Henry Mwape
- Zambian Carnivore Programme, Mfuwe, Eastern Province, Zambia
| | - Twakundine Simpamba
- Department of National Parks and Wildlife, South Luangwa Area Management Unit, Mfuwe, Eastern Province, Zambia
| | - Matthew S Becker
- Department of Ecology, Montana State University, Bozeman, Montana, USA
- Zambian Carnivore Programme, Mfuwe, Eastern Province, Zambia
| |
Collapse
|
2
|
Bhagwat T, Hess A, Horning N, Khaing T, Thein ZM, Aung KM, Aung KH, Phyo P, Tun YL, Oo AH, Neil A, Thu WM, Songer M, LaJeunesse Connette K, Bernd A, Huang Q, Connette G, Leimgruber P. Losing a jewel-Rapid declines in Myanmar's intact forests from 2002-2014. PLoS One 2017; 12:e0176364. [PMID: 28520726 PMCID: PMC5435175 DOI: 10.1371/journal.pone.0176364] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Accepted: 04/10/2017] [Indexed: 12/02/2022] Open
Abstract
New and rapid political and economic changes in Myanmar are increasing the pressures on the country’s forests. Yet, little is known about the past and current condition of these forests and how fast they are declining. We mapped forest cover in Myanmar through a consortium of international organizations and environmental non-governmental groups, using freely-available public domain data and open source software tools. We used Landsat satellite imagery to assess the condition and spatial distribution of Myanmar’s intact and degraded forests with special focus on changes in intact forest between 2002 and 2014. We found that forests cover 42,365,729 ha or 63% of Myanmar, making it one of the most forested countries in the region. However, severe logging, expanding plantations, and degradation pose increasing threats. Only 38% of the country’s forests can be considered intact with canopy cover >80%. Between 2002 and 2014, intact forests declined at a rate of 0.94% annually, totaling more than 2 million ha forest loss. Losses can be extremely high locally and we identified 9 townships as forest conversion hotspots. We also delineated 13 large (>100,000 ha) and contiguous intact forest landscapes, which are dispersed across Myanmar. The Northern Forest Complex supports four of these landscapes, totaling over 6.1 million ha of intact forest, followed by the Southern Forest Complex with three landscapes, comprising 1.5 million ha. These remaining contiguous forest landscape should have high priority for protection. Our project demonstrates how open source data and software can be used to develop and share critical information on forests when such data are not readily available elsewhere. We provide all data, code, and outputs freely via the internet at (for scripts: https://bitbucket.org/rsbiodiv/; for the data: http://geonode.themimu.info/layers/geonode%3Amyan_lvl2_smoothed_dec2015_resamp)
Collapse
Affiliation(s)
- Tejas Bhagwat
- Smithsonian Conservation Biology Institute, Conservation Ecology Center, Front Royal, Virginia, United States of America
| | - Andrea Hess
- Department of Geosciences, University of Bayreuth, Bayreuth, Germany
| | - Ned Horning
- American Museum of Natural History, New York, New York, United States of America
| | - Thiri Khaing
- EcoDev/ALARM, Kamayut Township, Yangon, Myanmar
- GMAP, Hlaing Township, Yangon, Myanmar
| | - Zaw Min Thein
- EcoDev/ALARM, Kamayut Township, Yangon, Myanmar
- GMAP, Hlaing Township, Yangon, Myanmar
| | | | - Kyaw Htet Aung
- EcoDev/ALARM, Kamayut Township, Yangon, Myanmar
- GMAP, Hlaing Township, Yangon, Myanmar
| | - Paing Phyo
- EcoDev/ALARM, Kamayut Township, Yangon, Myanmar
- GMAP, Hlaing Township, Yangon, Myanmar
| | - Ye Lin Tun
- EcoDev/ALARM, Kamayut Township, Yangon, Myanmar
- GMAP, Hlaing Township, Yangon, Myanmar
| | - Aung Htat Oo
- EcoDev/ALARM, Kamayut Township, Yangon, Myanmar
- GMAP, Hlaing Township, Yangon, Myanmar
| | | | - Win Myo Thu
- EcoDev/ALARM, Kamayut Township, Yangon, Myanmar
| | - Melissa Songer
- Smithsonian Conservation Biology Institute, Conservation Ecology Center, Front Royal, Virginia, United States of America
| | - Katherine LaJeunesse Connette
- Smithsonian Conservation Biology Institute, Conservation Ecology Center, Front Royal, Virginia, United States of America
| | - Asja Bernd
- EcoDev/ALARM, Kamayut Township, Yangon, Myanmar
| | - Qiongyu Huang
- Smithsonian Conservation Biology Institute, Conservation Ecology Center, Front Royal, Virginia, United States of America
| | - Grant Connette
- Smithsonian Conservation Biology Institute, Conservation Ecology Center, Front Royal, Virginia, United States of America
| | - Peter Leimgruber
- Smithsonian Conservation Biology Institute, Conservation Ecology Center, Front Royal, Virginia, United States of America
- * E-mail:
| |
Collapse
|