An empirical test of source–sink dynamics induced by hunting
Article first published online: 28 JUL 2005
Journal of Applied Ecology
Volume 42, Issue 5, pages 910–920, October 2005
How to Cite
NOVARO, A. J., FUNES, M. C. and WALKER, R. S. (2005), An empirical test of source–sink dynamics induced by hunting. Journal of Applied Ecology, 42: 910–920. doi: 10.1111/j.1365-2664.2005.01067.x
- Issue published online: 28 JUL 2005
- Article first published online: 28 JUL 2005
- Received 16 November 2004; final copy received 20 April 2005 Editor: Rob Freckleton
- attractive sink;
- landscape change;
- Pseudalopex culpaeus
- 1Under the source–sink model, persistence of populations in habitat sinks, where deaths outnumber births, depends on dispersal from high-quality habitat sources, where births outnumber deaths. The persistence of the regional population depends on the proportion of sink relative to source habitat.
- 2Hunting that occurs in some parts of the landscape and not in others can create patches where deaths outnumber births. We tested whether hunting of culpeo foxes Pseudalopex culpaeus, which is patchily distributed in relatively homogeneous habitat in Argentine Patagonia, induces source–sink dynamics.
- 3On Patagonian sheep ranches, culpeos are hunted for fur and to protect sheep, and on cattle ranches hunting is usually banned. We monitored culpeo densities using scent stations and estimated survival, fecundity and dispersal by radio-tracking 44 culpeos and analysing carcasses collected from hunters on two cattle and four sheep ranches between 1989 and 1997.
- 4Survival of juvenile culpeos was lower on hunted than unhunted ranches, mainly as a result of hunting mortality. Reproduction could not compensate for high mortality on hunted ranches. Interruption of hunting led to an increase in juvenile survival, indicating that hunting and natural mortality were not compensatory. We concluded that sheep ranches were sinks because of the high mortality and that sink populations may be maintained by dispersal from cattle ranches.
- 5We used a simulation model to assess implications of changes in the proportion of source and sink areas on population dynamics. The percentage of land on cattle ranches in the study area was 37%. Current hunting pressure on culpeos would not be sustainable if that percentage fell below 30%.
- 6Synthesis and applications. Source–sink dynamics may occur in landscapes where hunting is intense and spatially heterogeneous. Wildlife management traditionally monitors demographic rates to evaluate the sustainability of hunting, but our results suggest that the size and spatial arrangement of areas with and without hunting should be considered as well. In regions where enforcement and monitoring are limited, securing large and regularly distributed source areas for hunted species may be more effective than trying to regulate harvest size.