Journal Article

Reserve design for territorial species: the effects of patch size and spacing on the viability of the Northern Spotted Owl

McKelvey, Kevin S., Lamberson, Roland H., Noon, Barry R., Voss, Curtis

1994

Overview

Designing a reserve system for a threatened territorial species such as the Northern Spotted Owl requires the balancing of biological necessity against economic reality. The Spotted Owl conservation plan and the Pacific Northwest timber industry are in conflict because both demand large areas of mature and old-growth coniferous forest. The primary focus of this paper is the efficient design of a reserve system for territorial species with obligate juvenile dispersal. We examine the relationship between the degree of aggregation of suitable owl habitat, the level of occupancy of that habitat by pairs of Spotted Owls, and the likelihood of owl persistence given different amounts and spatial arrangements of suitable habitat across the landscape. We develop a population model for Spotted Owls that includes an abstracted forest landscape where suitable owl habitat is arrayed in clusters embedded in a matrix not suitable for owl habitation. We conclude from our study of this model that, for any given fraction of the landscape set aside in reserves, the level of occupancy (efficiency of use) of that area will increase as the aggregation of suitable habitat increases. After the reserves reach a size that includes territories for 20 to 25 owl pairs, however, there are diminishing returns from further increases. Preserving connectivity and increasing the geographical extent of the reserve begin to outweigh increased size in importance in insuring the long-term viability of the species.

• Publisher: Blackwell Science Inc,Blackwell Scientific Publications,Blackwell
• Subject: aggression / AGGRESSIVE BEHAVIOUR / Animal, plant and microbial ecology / Applied ecology / Biological and medical sciences / BOSQUE DE CONIFERAS / COMPORTAMIENTO AGRESIVO / COMPORTEMENT AGRESSIF / CONCEPTION / CONIFEROUS FORESTS / CONSERVACION DE LA NATURALEZA / CONSERVATION AREAS / Conservation biology / CONSERVATION DE LA NATURE / Conservation, protection and management of environment and wildlife / Demography / DESIGN / DISENO / ESPECE PROTEGEE / ESPECIES PROTEGIDAS / EVOLUCION DE LA POBLACION / EVOLUTION DE LA POPULATION / Forest conservation / Forest habitats / FORET RESINEUSE / Fundamental and applied biological sciences. Psychology / Habitat conservation / habitat conservation areas / MODELE / MODELOS / NATURE CONSERVATION / NATURE RESERVES / Owls / PACIFIC NORTHWEST STATES OF USA / Pacific States / Parks, reserves, wildlife conservation. Endangered species: population survey and restocking / POPULATION DYNAMICS / PROTECTED SPECIES / RESERVAS NATURALES / RESERVE NATURELLE / SPATIAL DISTRIBUTION / Species / STRIGIFORMES / STRIX OCCIDENTALIS / Strix occidentalis caurina / TERRITORIALITY / Viability / WILDLIFE CONSERVATION / Wildlife habitats