A habitat network for terrestrial wildlife in the Interior Columbia Basin

Habitat managers need information about landscape conditions in relation to the composite requirements of species that deserve attention in conservation planning. Consequently, we characterized and mapped a broad-scale network of habitats for five suites of terrestrial vertebrates in the 58 million-ha Interior Columbia Basin (Basin). These five suites, referred to as Families, are composed of 44 species whose habitats have declined strongly from historical (circa 1850-1890) to current periods in the Basin, and thus are of conservation focus. Two of the five Families consist of species that depend on old forests. Species in another Family depend on early-seral forests. Species in the remaining Families depend on sagebrush-steppe or open canopy sagebrush and grasslands. For each Family, we characterized current habitat conditions at the scale of the watershed (mean size of 22 500 ha). Each watershed was classified as one of three conditions. Watersheds in Condition 1 contained habitats whose quality or abundance have changed little since the historical period. By contrast, watersheds in Condition 2 or 3 contained habitats that have changed from historical conditions, but in different ways. Watersheds in Condition 2 had habitats of high abundance but moderate resiliency and quality, whereas watersheds in Condition 3 contained habitats of low abundance or low resiliency and quality. The majority of watersheds (59-80%) were in Condition 3 for all five Families, whereas the lowest percentage (5-25%) of watersheds was in Condition 2 for four of five Families. Connectivity among watersheds for all Families appeared low in many parts of the Basin due to spatial gaps associated with areas of habitat extirpation. Our condition maps constitute a broad-scale network of habitats that could be useful for developing multi-species research hypotheses and management strategies for the Basin.Wisdom et al "A habitat network for terrestrial wildlife in the Interior Columbia Basin." Northwest Science. 2002; 76(1): 1-1

Effects of Fire on Landscape Heterogeneity in Yellowstone National Park, Wyoming

A map of burn severity resulting from the 1988 fires that occurred in Yellowstone National Park (YNP) was derived from Landsat Thematic Mapper (TM) imagery and used to assess the isolation of burned areas, the heterogeneity that resulted from fires burning under moderate and severe burning conditions, and the relationship between heterogeneity and fire size. About 80% of the park is covered with coniferous forests dominated by lodgepole pine (Pinus contorta var. latifolia). The majority of severely burned areas were within close proximity (50 to 200 m) to unburned or lightly burned areas, suggesting that few burned sites are very far from potential sources of propagules for plant re-establishment. Fires that occurred under moderate burning conditions early during the 1988 fire season resulted in a lower proportion of crown fire than fires that occurred under severe burning conditions later in the season. Increased dominance and contagion of burn severity classes and decrease in the edge:area ratio for later fires indicated a slightly more aggregated burn pattern compared to early fires. The proportion of burned area in different burn severity classes varied as a function of daily fire size. When daily area burned was relatively low, the proportion of burned area in each burn severity class varied widely. When daily burned area exceeded 1250 ha, the burned area contained about 50% crown fire, 30% severe surface burn, and 20% light surface burn. Understanding the effect of fire on landscape heterogeneity is important because the kinds, amounts, and spatial distribution of burned and unburned areas may influence the reestablishment of plant species on burned sites