Category: Ecological Research
Title: Breeding bird responses to juniper woodland expansion
Author: Rosenstock, S.S. , Riper, C.V.
Subject: Pinyon-Juniper, Grasses, Succession, Birds
Abstract: In recent times, pinyon (Pinus spp.)-juniper (Juniperus spp.) woodlands have expanded into large portions of the Southwest historically occupied by grassland vegetation. From 1997?1998, we studied responses of breeding birds to one-seed juniper (J. monosperma) woodland expansion at 2 grassland study areas in northern Arizona. We sampled breeding birds in 3 successional stages along a grassland-woodland gradient: un-invaded grassland, grassland undergoing early stages of juniper establishment, and developing woodland. Species composition varied greatly among successional stages and was most different between endpoints of the gradient. Ground-nesting grassland species predominated in uninvaded grassland but declined dramatically as tree density increased. Tree- and cavity-nesting species increased with tree density and were most abundant in developing woodland. Restoration of juniper-invaded grasslands will benefit grasslandobligate birds and other wildlife.
Source: Journal of Range Management
Publisher: Society for Range Management, http://www.rangelands.org/