Climate Change Habitat Model Forecasts for Eight Owl Species in the Southwestern US

Abstract

The high-resolution forecasting of vegetation type shifts may prove essential in anticipating and mitigating the impacts of future climate change on bird populations. Here, we used the US Forest Service Ecological Response Unit (ERU) classification to develop and assess vegetation-based breeding habitat profiles for eight owl species occurring in the foothills and mountains of the Southwestern US. Shifts in mapped habitat were forecast using an ecosystem vulnerability model based on the pre-1990 climate envelopes of ERUs and the Intergovernmental Panel on Climate Change’s (IPCC) A1B moderate-emission scenario for the future climate. For five of the eight owl species, the regional breeding habitat extent was projected to decline by at least 60% by 2090. Three species, the boreal owl (Aegolius funereus; at the trailing edge of its distribution), flammulated owl (Psiloscops flammeolus), and northern pygmy-owl (Glaucidium gnoma), were projected to experience the steepest habitat loss rates of 85%, 85%, and 76%, respectively. Projected vegetation shifts overlaid with well-documented flammulated owl breeding populations showed the complete or near complete loss of habitat by 2090 in areas of montane forest currently supporting dense aggregations of owl territories. Generalist or lower-elevation owl species were predicted to be less impacted, while, for the whiskered screech-owl (Megascops trichopsis), the contraction of the current habitat was nearly offset by a projected northward expansion. In general, the results of this study suggest high exposure to climate change impacts for the upper-elevation forest owls of semi-arid Southwestern North America. Long-distance migration and low natal philopatry may prove important to some montane owl populations in adapting to the regional loss of habitat.

Owls’ Responses to Environmental Challenges

“…This Special Issue focuses on the adaptability of owls to various kinds of environmental changes, including habitat alterations and climate change [ 4 , 5 , 6 , 7 , 8 , 9 , 10 ]. Both direct and indirect effects of climate change on the habitat and food availability of owl populations are considered.…”

“…Both direct and indirect effects of climate change on the habitat and food availability of owl populations are considered. Various populations of the Tawny Owl Strix aluco [ 4 , 7 , 8 ] as well as some other species of owls from Europe [ 5 , 6 , 9 ] and North America [ 10 ] serve as examples.…”

“…The conservation and preservation of areas with potential for the distribution and refugia of Boreal and Eurasian Pygmy Owls are therefore important in the face of climate change. Thus, the forecasting of vegetation-type shifts may prove essential in anticipating and mitigating the impacts of future climate change on bird populations [ 10 ]. For instance, high exposure to climate change is suggested to impact the upper-elevation forest owls of semi-arid Southwestern North America, and long-distance migration and low natal philopatry may prove important to some montane owl populations in adapting to the regional loss of habitat.…”