Document Details
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Title |
Badger Habitat Use and Movements in Forested Ecosystems | ||||||||||||
Author |
Larsen, Karl W. | ||||||||||||
Date |
2009 | ||||||||||||
Abstract |
The BC subspecies of badger (ssp. jeffersoni)is one of BC?s most endangered mammals, with estimates placing the total provincial population at fewer than 340 [1]. Consequently, badgers are on the ?red list? within the province, and are considered ?endangered? at the federal level. The animals generally are restricted to the south-central portion of the province, where research projects have been conducted on sub-populations found in and around the Thompson-Nicola and East Kootenay valleys. Badgers often are stereotyped as a grassland species, yet recent research [2, 3] has revealed that they are much more of a habitat generalist than previously believed. These research projects also have isolated two main factors contributing to the continued decline of badgers in BC: (1) a historical and current deterioration of habitat, and (2) road mortality caused by major transportation corridors running through valley bottoms where badgers exist. Badgers in BC have extremely large home ranges [2, 3] as compared to conspecifics further south, suggesting that habitat is suboptimal and/or access to mates is constrained by low densities of animals. The large home ranges cause animals to make long forays, bringing them onto roads and railway lines. However, data collected on the home range of these animals also reveals their use of a wide range of habitats other than the valley-bottom grasslands. For example, badgers have been shown to use higher-elevation forests, including recent cutblocks where food (e.g., ground squirrels) is available. These studies have indicated that plans to maintain badgers in this province must encompass a wider range of habitat types and management activities than previously thought. In 2003, members of our research team (notably Packham) started to become increasingly aware of the presence of badgers in the Cariboo region of BC. The Cariboo is a broad, flat plateau, composed of a matrix of grasslands (used heavily for livestock grazing), wetlands, aspen, and pine/Douglas-fir forests. From a conservation standpoint, the Cariboo badgers are inherently of interest because they represent the northernmost periphery of the animals in the province. Peripheral populations often represent 'strongholds' for species undergoing declines, and may be important reservoirs of genetic diversity [4]. In many cases, broad landscape approaches may be efficient in protecting peripheral populations such as the Cariboo badgers [5,6], but variations in life-history and a different demography often make detailed information on these peripheral populations critical [6], especially for maintaining genetic variability [7]. Further attention to the Cariboo badgers also appears warranted because they appear increasingly affected by human activity, following the fate of their more-southern conspecifics. Preliminary research (Packham) using DNA sampling at burrows has demonstrated home ranges may be even larger than seen further south (up to 1200 km2), and the growing awareness of the animals has revealed that road mortality is also taking its toll. Forest harvesting, the recent mountain pine beetle epidemic, and a projected increase in vehicular traffic in the region all indicate the animals in the Cariboo could face extirpation, not unlike that seen within the southern parts of the province. Fortunately, the fact that pressure on the population from human activities may be relatively recent suggests there may still be time to prevent the drastic decline of the animals as seen in other regions. However, this will not be an easy task: other preliminary research (Packham unpubl.) using sightings, burrow records, and scat analysis indicates the Cariboo badgers are not only using grassland habitats, but also travel and den in forested areas,and feed on species linked to forests (e.g. red-backed voles, hares, squirrels) and even riparian zones (muskrats, waterfowl). Effective management plans therefore will need to be broad, but ... | ||||||||||||
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