Ghosts of habitat past: the relative contribution of landscape change on current habitat associations of shrubsteppe birds

Publication Type:

Journal Article

Authors:

Knick, Steven T.; Rotenberry, John T.

Source:

Ecology, Ecological Society of America, Volume 81, Issue 1, p.220-227 (2000)

Call Number:

A00KNI01IDUS

Keywords:

Amphispiza belli, Brewer's Sparrow, Eremophila alpestris, horned lark, Oreoscoptes montanus, Sage sparrow, Sage Thrasher, Spizella breweri, Sturnella neglecta, western meadowlark

Abstract:

Models of habitat associations for species often are developed with an implicit assumption that habitats are static, even though recent disturbance may have altered the landscape. We tested our hypothesis that trajectory and magnitude of habitat change influenced observed distribution and abundance of passerine birds breeding in shrubsteppe habitats of southwestern Idaho. Birds in this region live in dynamic landscapes undergoing predominantly large-scale, radical, and unidirectional habitat change because wildfires are converting shrublands into expanses of exotic annual grasslands. We used data from field surveys and satellite image analyses in a series of redundancy analyses to partition variances and to determine the relative contribution of habitat change and current landscapes. Although current habitats explained a greater proportion of total variation, changes in habitat and measures of habitat richness and texture also contributed to variation in abundance of Horned Larks (Eremophila alpestris), Brewer's Sparrows (Spizella breweri), and Sage Sparrows (Amphispiza belli). Abundance of birds was insensitive to scale for nonspatial habitat variables. In contrast, spatial measures of habitat richness and texture in the landscape were significant only at large spatial scales. Abundance of Horned Larks, Western meadowlarks (Sturnella neglecta), and Brewer's Sparrows, but not Sage Thrashers (Oreoscoptes montanus) or Sage sparrows, was positively correlated with changes toward stable habitats. Because dominant habitat changes were toward less stable conditions, regional declines of those birds in shrubsteppe habitats reflect current landscapes as well as the history, magnitude, and trajectory of habitat change.

Notes:

Reference Code: A00KIN01IDUS

Full Citation: Knick, S. T. and J. T. Rotenberry. 2000. Ghosts of habitat past: the relative contribution of landscape change on current habitat associations of shrubsteppe birds. Ecology 81(1): 220-227.

Location: ANIMAL EF: BIRDS