Positive Effects on Game Species of Top Predators by Controlling Smaller Predator Populations: An Example with Lynx, Mongooses, and Rabbits

Top predators have often been persecuted because of their supposed negative effects on species of economic concern on which they feed. In some cases, however, they may actually benefit their prey through intraguild predation on other smaller predators that share the prey. In each of two representative situations, in one of which lynx were present and in the other absent, we (1) estimated gross numbers of rabbits taken by lynx and Egyptian mongooses (smaller predators that are themselves preyed upon by lynx); (2) simulated size-structured rabbit populations of different densities, taking into account the reproductive value of the individuals taken by predators; and (3) estimated actual rabbit densities. Numbers of rabbits taken by predators during a year werefound to be between 4.8 and 9.5 times greater when lynx were notpresent. After ayear, rabbit population growth for an initial rabbit density of 15/ha was between 12% and 22% lower when lynx were not present For lower initial rabbit densities, the positive effect of lynx presence on rabbits was greater. Actual rabbit densities in the areas used by lynx were 2-4 times higher than in areas not used by lynx, even though these areas were similar or identical in habitat composition. These results support the suggestion that removal of top predators may sometimes have a negative effect on prey populations of human economic concern.

[1]  H. G. Lloyd.  The red fox. , 1980 .

[2]  Stuart L. Pimm,et al.  Food web design and the effect of species deletion , 1980 .

[3]  David R. Anderson,et al.  Wildlife Monographs: Estimation of Density from Line Transect Sampling of Biological Populations , 1981 .

[4]  J. Karr.  Avian Extinction on Barro Colorado Island, Panama: A Reassessment , 1982, The American Naturalist.

[5]  David S. Wilcove,et al.  Nest Predation in Forest Tracts and the Decline of Migratory Songbirds , 1985 .

[6]  Philosophy of Wolf Policies I: General Principles and Preliminary Exploration of Selected Norms , 1987 .

[7]  Douglas T. Bolger,et al.  Reconstructed Dynamics of Rapid Extinctions of Chaparral‐Requiring Birds in Urban Habitat Islands , 1988 .

[8]  P. Holgate,et al.  Matrix Population Models. , 1990 .

[9]  J. M. Wallage-Drees.  A field study on seasonal changes in the circadian activity , 1989 .

[10]  B. Mclellan.  Dynamics of a grizzly bear population during a period of industrial resource extraction. I. Density and age–sex composition , 1989 .

[11]  J. Veiga,et al.  Food habits and the survival and growth of nestlings in two sympatric kites (Milvus milvus and Milvus migrans) , 1990 .

[12]  M. Delibes,et al.  Factores de transformación para el cálculo de la biomasa consumida por Gineta (Genetta genetta) y Meloncillo (Herpestes ichneumon) (Carnivora, Mammalia) , 1990 .

[13]  Jorge E. Rabinovich,et al.  A population-dynamics simulation model of the main vectors of Chagas' Disease transmission, Thodnius prolixus and Triatoma infestans , 1990 .

[14]  M. Delibes,et al.  Energy expenditure and prey requirements of free-ranging Iberian lynx in southwestern Spain , 1991 .

[15]  F. Palomares,et al.  The status and distribution of the Iberian lynx Felis pardina (Temminck) in Coto Doñana Area, SW Spain , 1991 .

[16]  THE IMPACT OF HEN HARRIERS ON RED GROUSE BREEDING SUCCESS , 1991 .

[17]  C. Fernandez.  Variation clinale du régime alimentaire et de la reproduction chez l'Aigle royal (Aquila chrysaëtos L.) sur le versant sud des Pyrénées , 1991, Revue d'Écologie (La Terre et La Vie).

[18]  M. Delibes,et al.  Current range and status of the Iberian lynx Felis pardina Temminck, 1824 in Spain , 1992 .

[19]  Lynn A. Maguire,et al.  Integrating Biological and Sociological Concerns in Endangered Species Management: Augmentation of Grizzly Bear Populations , 1992 .

[20]  F. Palomares.  Opportunistic feeding of the Egyptian mongoose, Herpestes ichneumon (L.) in Southwestern Spain , 1993, Revue d'Écologie (La Terre et La Vie).

[21]  M. Delibes,et al.  Environmental factors influencing the seasonal daily activity of the European rabbit (Oryctolagus cuniculus) in a Mediterranean area , 1993 .

[22]  Raptors and game: the assessment of a net predation rate , 1993 .

[23]  F. Palomares,et al.  Social organization in the Egyptian mongoose: group size, spatial behaviour and inter-individual contacts in adults , 1993, Animal Behaviour.

[24]  James H. Brown,et al.  Are Declines in North American Insectivorous Songbirds Due to Causes on the Breeding Range , 1993 .

[25]  F. Palomares,et al.  Spatial Relationships Between Iberian Lynx and Other Carnivores in an Area of South-Western Spain , 1996 .