Browsing by Author "Harmsen, Bart J."
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- Assessing global patterns in mammalian carnivore occupancy and richness by integrating local camera trap surveysRich, Lindsey N.; Davis, Courtney L.; Farris, Zachary J.; Miller, David A. W.; Tucker, Jody M.; Hamel, Sandra; Farhadinia, Mohammad S.; Steenweg, Robin; Di Bitetti, Mario S.; Thapa, Kanchan; Kane, Mamadou D.; Sunarto, Sunarto; Robinson, Nathaniel P.; Paviolo, Agustin; Cruz, Paula; Martins, Quinton; Gholikhani, Navid; Taktehrani, Atieh; Whittington, Jesse; Widodo, Febri A.; Yoccoz, Nigel G.; Wultsch, Claudia; Harmsen, Bart J.; Kelly, Marcella J. (2017-08)Aim: Biodiversity loss is a major driver of ecosystem change, yet the ecological data required to detect and mitigate losses are often lacking. Recently, camera trap surveys have been suggested as a method for sampling local wildlife communities, because these observations can be collated into a global monitoring network. To demonstrate the potential of camera traps for global monitoring, we assembled data from multiple local camera trap surveys to evaluate the interchange between fine- and broad-scale processes impacting mammalian carnivore communities. Location: Argentina, Belize, Botswana, Canada, Indonesia, Iran, Madagascar, Nepal, Norway, Senegal, South Africa, and the U.S.A. Methods: We gathered camera trap data, totalling >100,000 trap nights, from across five continents. To analyse local and species-specific responses to anthropogenic and environmental variables, we fitted multispecies occurrence models to each study area. To analyse global-level responses, we then fitted a multispecies, multi-area occurrence model. Results: We recorded 4,805 detections of 96 mammalian carnivore species photographed across 1,714 camera stations located in 12 countries. At the global level, our models revealed that carnivore richness and occupancy within study areas was positively associated with prey availability. Occupancy within study areas also tended to increase with greater protection and greater distances to roads. The strength of these relationships, however, differed among countries. Main conclusions: We developed a research framework for leveraging global camera trap data to evaluate patterns of mammalian carnivore occurrence and richness across multiple spatial scales. Our research highlights the importance of intact prey populations and protected areas in conserving carnivore communities. Our research also highlights the potential of camera traps for monitoring wildlife communities and provides a case study for how this can be achieved on a global scale. We encourage greater integration and standardization among camera trap studies worldwide, which would help inform effective conservation planning for wildlife populations both locally and globally.
- Ecological correlates of the spatial co-occurrence of sympatric mammalian carnivores worldwideDavis, Courtney L.; Rich, Lindsey N.; Farris, Zachary J.; Kelly, Marcella J.; Di Bitetti, Mario S.; Di Blanco, Yamil; Albanesi, Sebastian; Farhadinia, Mohammad S.; Gholikhani, Navid; Hamel, Sandra; Harmsen, Bart J.; Wultsch, Claudia; Kane, Mamadou D.; Martins, Quinton; Murphy, Asia J.; Steenweg, Robin; Sunarto, Sunarto; Taktehrani, Atieh; Thapa, Kanchan; Tucker, Jody M.; Whittington, Jesse; Widodo, Febri A.; Yoccoz, Nigel G.; Miller, David A. W. (2018-09)The composition of local mammalian carnivore communities has far-reaching effects on terrestrial ecosystems worldwide. To better understand how carnivore communities are structured, we analysed camera trap data for 108087 trap days across 12 countries spanning five continents. We estimate local probabilities of co-occurrence among 768 species pairs from the order Carnivora and evaluate how shared ecological traits correlate with probabilities of co-occurrence. Within individual study areas, species pairs co-occurred more frequently than expected at random. Co-occurrence probabilities were greatest for species pairs that shared ecological traits including similar body size, temporal activity pattern and diet. However, co-occurrence decreased as compared to other species pairs when the pair included a large-bodied carnivore. Our results suggest that a combination of shared traits and top-down regulation by large carnivores shape local carnivore communities globally.
- Long term monitoring of jaguars in the Cockscomb Basin Wildlife Sanctuary, Belize; Implications for camera trap studies of carnivoresHarmsen, Bart J.; Foster, Rebecca J.; Sanchez, Emma E.; Gutierrez-Gonzalez, Carmina E.; Silver, Scott C.; Ostro, Linde E. T.; Kelly, Marcella J.; Kay, Elma; Quigley, Howard B. (PLOS, 2017-06-28)In this study, we estimate life history parameters and abundance for a protected jaguar population using camera-trap data from a 14-year monitoring program (2002–2015) in Belize, Central America. We investigated the dynamics of this jaguar population using 3,075 detection events of 105 individual adult jaguars. Using robust design open population models, we estimated apparent survival and temporary emigration and investigated individual heterogeneity in detection rates across years. Survival probability was high and constant among the years for both sexes (φ = 0.78), and the maximum (conservative) age recorded was 14 years. Temporary emigration rate for the population was random, but constant through time at 0.20 per year. Detection probability varied between sexes, and among years and individuals. Heterogeneity in detection took the form of a dichotomy for males: those with consistently high detection rates, and those with low, sporadic detection rates, suggesting a relatively stable population of ‘residents’ consistently present and a fluctuating layer of ‘transients’. Female detection was always low and sporadic. On average, twice as many males than females were detected per survey, and individual detection rates were significantly higher for males. We attribute sex-based differences in detection to biases resulting from social variation in trail-walking behaviour. The number of individual females detected increased when the survey period was extended from 3 months to a full year. Due to the low detection rates of females and the variable ‘transient’ male subpopulation, annual abundance estimates based on 3-month surveys had low precision. To estimate survival and monitor population changes in elusive, wide-ranging, low-density species, we recommend repeated surveys over multiple years; and suggest that continuous monitoring over multiple years yields even further insight into population dynamics of elusive predator populations.
- Long‐term monitoring of ocelot densities in BelizeSatter, Christopher B.; Augustine, Ben C.; Harmsen, Bart J.; Foster, Rebecca J.; Sanchez, Emma E.; Wultsch, Claudia; Davis, Miranda L.; Kelly, Marcella J. (The Wildlife Society, 2019-01)Ocelots (Leopardus pardalis) are listed as least concern on the International Union for Conservation of Nature (IUCN) Red list of Threatened Species, yet we lack knowledge on basic demographic parameters across much of the ocelot's geographic range, including population density. We used camera‐trapping methodology and spatially explicit capture‐recapture (SECR) models with sex‐specific detection function parameters to estimate ocelot densities across 7 field sites over 1 to 12 years (from data collected during 2002–2015) in Belize, Central America. Ocelot densities in the broadleaf rainforest sites ranged between 7.2 and 22.7 ocelots/100 km2, whereas density in the pine (Pinus spp.) forest site was 0.9 ocelots/100 km2. Applying an inverse‐variance weighted average over all years for each broadleaf site increased precision and resulted in average density ranging from 8.5 to 13.0 ocelots/100 km2. Males often had larger movement parameter estimates and higher detection probabilities at their activity centers than females. In most years, the sex ratio was not significantly different from 50:50, but the pooled sex ratio estimated using an inverse weighted average over all years indicated a female bias in 1 site, and a male bias in another. We did not detect any population trends as density estimates remained relatively constant over time; however, the power to detect such trends was generally low. Our SECR density estimates were lower but more precise than previous estimates and indicated population stability for ocelots in Belize.
- Sex-specific population dynamics of ocelots in Belize using open population spatial capture-recaptureSatter, Christopher B.; Augustine, Ben C.; Harmsen, Bart J.; Foster, Rebecca J.; Kelly, Marcella J. (Ecological Society of America, 2019-07)We used open population, spatial capture-recapture (SCR) models to estimate sex-specific density, survival, per capita recruitment, and population growth rate of ocelots (Leopardus pardalis) at five sites in Belize with up to 12 yr of data per site. Open population SCR models enabled us to separate survival and recruitment from migration using an ecologically realistic, spatially explicit movement model. Yearly survival probability across 4 broadleaf forest sites was estimated at 0.73-0.84 for males and 0.81-0.87 for females, with no clear indication of sex differences. Yearly per capita recruitment was estimated across four broadleaf forest sites at 0.06-0.08 recruits/N for males and 0.09-0.12 recruits/N for females, again with no clear indication of sex differences. At a pine forest site with a population comprised largely of males, survival and recruitment estimates were similar to the broadleaf sites. Population densities in the broadleaf forest sites ranged from 6.5 to 14.7 ocelots/100 km(2), and 0.9-2.5 ocelots/100 km(2) in the pine forest site, with strong evidence of a female-biased sex ratio in the broadleaf sites and a male-biased sex ratio in the pine forest site. We also found strong evidence that female within-year space use at the broadleaf sites was smaller than that of males, and that within-year space use at the pine forest site was larger than that at broadleaf sites. Between-year home-range relocation at broadleaf sites was of a similar spatial scale as within-year space use, consistent with philopatry. We found evidence of a small population decline (posterior probability > 0.9) at two of four broadleaf sites; however, given the level of uncertainty about decline magnitudes, we suggest continued monitoring of these sites to increase site-years and gain further precision on population growth rate estimates. Estimating demographic parameters at large spatial and temporal scales is important for establishing reliable baseline estimates for future comparison and for understanding changes in population dynamics. Long-term data sets like those we collected are of particular importance for long-lived species living at low densities and large spatial scales, where not many individuals are exposed to capture in any one year.