Grantee Research Project Results

2000 Progress Report: Multi-scale Effects of Forest Fragmentation and Landscape Context on Population Health of Birds

EPA Grant Number: R827673
Title: Multi-scale Effects of Forest Fragmentation and Landscape Context on Population Health of Birds
Investigators: Martin, Thomas E. , Redmond, Roland L.
Institution: University of Montana
EPA Project Officer: Packard, Benjamin H
Project Period: October 1, 1999 through September 30, 2002 (Extended to September 30, 2003)
Project Period Covered by this Report: October 1, 1999 through September 30, 2000
Project Amount: $659,331
RFA: Regional Scale Analysis and Assessment (1999) RFA Text |  Recipients Lists
Research Category: Aquatic Ecosystems , Ecological Indicators/Assessment/Restoration

Objective:

Data from intensive studies of avian demography at replicated sites and multiple spatial scales within and among geographic regions will be used to assess the effects of spatial scale and landscape context on major factors (nest predation and Brown-headed Cowbird parasitism) that influence health of bird populations. We also will examine whether the effects of spatial scale and landscape context differ geographically, from east to west, across North America.

Results from this work will provide new and more general insight into the influence of spatial scale on fragmentation and landscape context in relation to nest predation and cowbird parasitism in birds. Moreover, results of this work can then be applied to land cover data across North America and across time to examine and predict the potential demographic consequences of future land use changes on bird populations.

Progress Summary:

Our work thus far has focused on two fronts: modeling avian population growth, and developing the geographical information system (GIS) databases needed to evaluate fragmentation and landscape context for BBIRD (Breeding Biology Research and monitoring Database) sites. The BBIRD database contains intensive demographic data for entire communities of bird species at sites across North America.

To date, we have developed a new stage-structured, matrix population model of the general avian life cycle for projecting population growth in passerine birds. Currently we are compiling life history data for approximately 100 species of North American passerines and simulating their populations using the model. The collection of species includes most of the North American species for which there is adequate life history information to simulate and determine source/sink dynamics in their populations. The collection also includes a majority of the species for which population and life history information is available in the BBIRD database. The BBIRD database will allow examination of geographic variation in model parameters and the consequences for avian demography as a function of geographic and landscape context. Preliminary results of simulations indicate that reproductive success is a leading factor limiting population growth. Projected population growth rates are most strongly affected by adult (age-2+) survival and nest success. Previous studies indicate nest success varies due to local (e.g., ground vs. cavity nest location), landscape (e.g., forest fragmentation), and geographic (e.g., climate) factors. This suggests that environmental, spatial, and geographic effects strongly influence which portions of a species' range experience population growth or decline. We can explore such population and demographic variation in a geographic context precisely through the BBIRD database because it provides a unique collection of reproductive information at local, landscape, and regional scales.

GIS work has focused on characterizing the landscape within a 100-km radius around each BBIRD site (see Figure 1), and has included the following tasks, all of which are ongoing and will continue in the upcoming year:

• Converting BBIRD locations to spatial format.
• Developing automated methods for downloading digital elevation models (DEMs) from the U.S. Geological Survey's web site and assembling them for 100-km radii surrounding individual BBIRD sites.
• Exploring methods for calculating fragmentation metrics. From the developers of FRAGSTATS software, we have learned that the spatial extent and complexity of our BBIRD landscapes may be too great for current software capabilities. If this proves to be the case, we will write our own programs to calculate metrics. These metrics will be calculated for landscapes defined as: (1) 100-km circles surrounding each forested BBIRD site (see Figure 1), and (2) 50-km circles surrounding individual plots within BBIRD sites.
• Assembling and evaluating land cover data. Although we originally planned to assemble and cross-walk data prepared for state Gap Analysis projects, we have since determined that the National Land Cover Data (NLCD) set provides a better option for our purposes. NLCD data are consistently mapped and currently available for the conterminous forty-eight states at fine scale (30-m resolution), whereas Gap Analysis data vary by project, and are not yet available for all states. Twenty-one land cover classes are mapped in NLCD. One drawback is that canopy class and size class data are not available, but these are not available in most GAP products either. For more information on NLCD, see:
  http://edcwww.cr.usgs.gov/programs/lccp/nationallandcover.html .

Future Activities:

Our next steps modeling avian population growth will be directed towards subsets of species within the BBIRD database. First, site-specific information on survival and reproductive success must be quantified from the BBIRD data. As we establish methods for quantifying these parameters from a subset of the data, we will expand to the entire database to estimate parameters at all available sites. Model simulations using these spatially-explicit parameters will yield information on dynamics of passerine populations across a variety of spatial scales and geographic areas in North America. Ultimately, this provides insight into populations at risk of extinction and areas where ecological effects (e.g., predation), abiotic factors (e.g., climate), or anthropogenic effects (e.g., toxics) are limiting species of concern.

Figure 1. The Bitterroot site and surrounding landscape, spanning the border between Idaho and Montana. Circle indicates 100 km radius around the center of the site, which includes 16 plots. Avian demographic data have been collected for these plots and are stored in the BBIRD database, which contains data for >30 forested sites in the conterminous USA.

In the upcoming year, we also will continue assembling GIS databases, first by finishing land cover and digital elevation, then turning to hydrography and roads. We also hope to work with FRAGSTATS developers to test beta versions of software updates, but if necessary, we will write our own programs to calculate fragmentation metrics using ArcInfo and Imagine software. Once metrics have been calculated, they will be integrated with the overall BBIRD database so that relationships between forest fragmentation and bird populations can be explored.

Journal Articles:

No journal articles submitted with this report: View all 8 publications for this project

Supplemental Keywords:

ecosystem, terrestrial, habitat, biology, avian ecology, modeling, surveys, remote sensing, geographic information systems., RFA, Scientific Discipline, Ecosystem Protection/Environmental Exposure & Risk, Forestry, Ecology, Biology, Regional/Scaling, Environmental Monitoring, habitat protection, forest fragmentation, remote sensing imagery, demographic consequences, population sensitivity, parasitism, land use, birds, agriculture, landscape context

Relevant Websites:

http://pica.wru.umt.edu/BBIRD/

Progress and Final Reports:

Original Abstract

2001 Progress Report

2002 Progress Report

Final Report