Global Climate Change and Range Shifts of Prairie Nesting Birds: Will the Habitat Be There?

Duration: August 1999 - September 2003

Grasslands are widely recognized as among the most imperiled ecosystems worldwide. In the United States, grasslands occur most extensively in the Central Grasslands region of the mid continent. Four of the five most widely used General Circulation Models (GCMs) indicate that future climate in the mid portion of the continent is likely to include higher average temperatures, increasing winter precipitation, declining summer precipitation, a decrease in soil moisture, and an increase in the frequency and severity of droughts. Uncertainties in the scale, extent, and distribution of climate change, in concert with our limited understanding of the life histories of most organisms, make anticipating the responses of biotic systems to global change exceedingly difficult. Only a few quantitative models have been developed for wildlife responses to climate change, and none of these deals explicitly with the fauna of the northern Great Plains. However, because birds are relatively well-studied, examination of the potential effects on birds and their habitat should provide insights into possible effects of climate change on other, less well-studied, organisms.

Grassland birds represent a valuable component of regional and global biological diversity. Over recent decades, they have shown steeper, more consistent, and more widespread population declines than any other group of North American species. Breeding Bird Survey data from 1966-1993 show that almost 70% of 29 grassland bird species surveyed had negative population trends during that period.
Like other creatures, grassland birds have evolved in particular types of habitats, under certain combinations of climatic conditions. In the past, marked changes in temperature or precipitation have led to major shifts in the distribution of several grassland bird species within one to a few years. These shifts took place in the absence of any other apparent changes in conditions within the species' typical habitats. These findings indicate that grassland birds are very sensitive to climatic features.

Scientific Objectives

While we can predict that climatic changes could dramatically alter the suitability of currently-occupied areas for grassland birds, we do not know enough to make useful predictions about particular responses to these changes. This study will attempt to redress this lack of understanding for approximately 15 species of grassland birds.


Application of Results:
This study addresses the question of whether individual species of grassland birds will be able to adapt to anticipated changes in global climate, and will identify those species most sensitive to change. This information will be useful for implementing new, or modifying existing, monitoring programs. It will also identify areas where the future climate might be suitable for particular species, thus facilitating appropriate management for those areas. Our major objectives are:

• To determine the habitat requirements of grassland birds at fine (meters) and coarse (hectares) scales, and predict where those habitats might occur under anticipated changes in global climate.
  
  
• To determine how distributions of grassland birds are influenced by climatic features (precipitation and temperature), and predict where suitable climate will occur under anticipated global climatic changes.
  

After meeting these two objectives, we will attempt to identify areas that will have both suitable climate and appropriate habitat under anticipated global climatic changes.

Approach

The general habitat needs of most grassland birds are fairly well known. However, the fine-scale, micro-habitat and micro-climatic features that influence bird use are not well understood. Through field studies, we will identify critical micro-site characteristics that contribute to habitat suitability for the species we are studying.GCMs will be used to predict where suitable climate will occur under climatic change. This information will be overlain on maps of habitat in the U.S. and Canada. Areas with both suitable habitat and suitable climate will be identified as areas of potential future occupancy for each species.

Scientific reports, academic theses, and popular articles are anticipated, as well as presentations at scientific meeting and other workshops are also anticipated. Where appropriate, products will be served on the Internet.

Products from this research will include:

• a literature review
• summaries of climatic information
  
• maps of the current ranges of the bird species of interest, and maps of predicted ranges under global climate change scenarios
  
• mathematical predictive equations
  
• suggestions for species management
  
• proposals for further inventory and monitoring activities
  Global Climate Change and Range Shifts of Prairie Nesting Birds: Will the Habitat Be There?
  
  

	More Information Primary Contact: Douglas H. Johnson, USGS Northern Prairie Wildlife Research Center E-mail Doug Johnson