Principal Investigator: Robert W. Klaver
Jennifer A. Vogel
Student Investigator: Joseph Lambert (M.S.)
Collaborators: Iowa Department of Natural Resources, U.S. Fish and Wildlife Service
Duration: January 2015 to August 2017
Funding Source(s): Iowa Department of Natural Resources, U.S. Fish and Wildlife Service
Goals and Objectives:
This project builds on a study that began in 2006 that was designed to compare bird response to four recently established habitat types within the Spring Run Wetland Complex in northwestern Iowa. The four habitat types were: (1) introduced grass (smooth brome) with scattered legumes, (2) a five-grass mix of native tall-grass species, planted before 2004, (3) a five-grass mix of native tall-grass species, planted in 2005-2007, and (4) a diverse mixture of grasses and forbs, planted with over 40 species, planted in 2005-2011.
The goal of this study was to compare grassland bird response in established fields that are more indicative of the long-term conditions in an area. Therefore, the same four habitat types were used in the study. An additional habitat type consisting of a mix of short-grass species and forbs, planted with over 100 species, was also incorporated into this phase of the project. Understanding invertebrate populations within the area will be helpful in explaining bird abundance.
Bird surveys, vegetation surveys, and invertebrate surveys have been completed. Grassland bird use among the planting types has been evaluated. Environmental variables responsible for shifts in grassland bird communities among the planting types over time have also been analyzed. Drafts presenting final results are under review.
A final thesis will be constructed and defended in June. Manuscripts will be submitted to the Journal of Wildlife Management and Ecological Restoration.
Conclusions and Recommendations:
Grassland bird communities differed among planting types and over time. Both vegetation composition and structure significantly influenced grassland bird community structure. A diversity of grassland planting types of differing ages are needed to provide the necessary habitat characteristics to conserve grassland bird populations.