Jennifer Vaughan recently completed her Master’s work at San Diego State University in the Department of Geography. Her thesis was titled “Local Geographies of the Coastal Cactus Wren and the Coastal California Gnatcatcher in Marine Corps Base Camp Pendleton California.” She also obtained her undergraduate degree at San Diego State University in the Department of Geography. Her interests lie in geospatial technologies and conservation issues.
The lives of birds are inherently geographic. Birds inhabit a variety of ecosystems across the globe. This characteristic of birds makes them ideal study subjects for geographers. Geographers are able to find connections between various geographies and birds (e.g., climate change) (Steinberg 2010). Ornithologists conduct most of the research on birds. However, geographers can contribute to avian research through a geographic perspective. Geographical research focusing on avian species considers the relationship between the species and their environment and not just the single organism in the environment.
Birds are often used as environmental indicators of ecosystem health because of their highly visible lives and their sensitivity to environmental changes. Birds are considered one of the most threatened vertebrate groups in depleted environments, with more than 1,000 species at risk for extinction (Martina Herrman, Costina, and Aron Costina 2010).
One growing threat to birds is climate change. More is known about birds’ response to climate change to date than any other species due to species and specific location research (Wormworth and Mallon 2006). There is evidence regarding the impacts of climate change on migration, breeding, and population dynamics of many avian populations across the globe (Crick 2004; Bolger, Patten, and Bostock 2005).
Ecosystems that are particularly vulnerable to climate change are in arid and semi-arid regions because of their high variability in annual precipitation. High variability in annual precipitation can lead to extensive drought periods that can change the natural cycle of the fire regime. The coastal sage scrub region in southern California is a semi-arid Mediterranean vegetation community. The impact of climate change on the avian community of coastal sage scrub is hard to predict, but warmer conditions and changes in annual precipitation may influence the reproduction and the availability of food for many sage scrub avian species (Bolger, Patten, and Bostock 2005; North American Bird Conservation Initiative 2009). Two coastal sage scrub avian species that are particularly vulnerable are the coastal cactus wren (Campylorhynchus brunneicapillus couesi) and the coastal California gnatcatcher (Polioptila californica californica).
It is projected that current climate change trends witnessed in southern California may shift coastal cactus wren populations out of their current range (Wiens 2010). It is suggested that shifts among species like the coastal cactus wren may produce unanticipated results, such as increased predation (Wiens 2010). It is also projected by the Audubon Society that if greenhouse gases continue to be emitted at high rates, the home range of the coastal California gnatcatcher is likely to be reduced by over 50 percent (Monahan and Langham 2009).
So how can geographers contribute to avian conservation? One approach is to examine birds in a three-tired approach, of what I like to call a local geography (Vaughan 2010). This three-tired approach examines the landscape that the species resides in and the landscape characteristics that the bird needs for survival at the landscape level.
The first approach is to examine the landscape characteristics; this will give us an insight to the landscape patterns (like fragmentation) that sustain avian species (Vaughan 2010). The landscape and its subsequent patterns play a major role in the spatial distribution of avian species. These patterns may shape how the individual species interact with eachother and their environment.
The next approach is to examine the specific habitat requirements of the species by using geospatial technologies, including habitat suitability analysis and species distribution modeling (Vaughan 2010). Habitat suitability analysis is used to produce probability maps for finding the landscape properties and potential spatial distribution of species (Store and Kangas 2001). Species distribution modeling is used often to predict and/or protect areas in a region that fulfill the ecological needs of a species niche (Anderson and Martínez-Meyer 2004).
The final approach gathers the information provided from the first two approaches and defines core habitat areas for the specie(s) in focus. Delineating core habitat areas will assist in better conservation management decisions, by helping managers understand where the species occurs and the landscape features that sustain them.
I used this local geography approach to study the populations of the coastal cactus wren and the coastal California gnatcatchers populations’ within a military installation in southern California. The research provided an insight into both species spatial distribution and habitat features on the military installation. The purpose was to assist the military in their conservation management practices by highlighting core habitat areas for both species. A major impact highlighted from my research was the role fire had on the environment in largely decreasing suitable habitat for both species. If core habitat areas are known for focal species, like the coastal cactus wren and coastal California gnatcatcher, conservation management practices can focus on those specific areas that may be critical for that species’ survival in that specific region.
The use of geography in avian research provides a uniquely spatial perspective by examining a broader perspective of the species and their habitat. In addition to traditional biological methods of avian research, geographic methods enable the researcher to explore different research objectives and questions that may provide a fuller understanding of the species and the best approaches to conserve their habitat. Geography enables a spatial perspective that is often missed in avian research, and that may prove beneficial not just in avian conservation, but in natural resource conservation in general.
Anderson, R. P., and E. Martínez-Meyer. 2004. Modeling Species’ Geographic Distributions for Preliminary Conservation Assessments: An Implementation with the Spiny Pocket Mice (Heteromys) of Ecuador. Biological Conservation 116 (2): 167-179.
Bolger, D. T., M.A. Patten, and D.C. Bostock. 2005. Avian Reproductive Fail in Response to an Extreme Climatic Event. Oecologia 142 (3): 398-406.
Crick, H. Q. P. 2004. The Impact of Climate Change on Birds. Ibis 146 (1): 48-56.
Hermann Martina, T., M.I. Costina, and A. M. Aron Costina. 2010. Roost Sites and Communal Behavior of Andean Condors in Chile. The Geographical Review 100 (2): 246 -262.
Monahan, W.B. and G. Langham. 2009. Curbing Emissions will Reduce Future California Bird Loss. Conservation Policy Brief. Audubon California.
North American Bird Conservation Initiative. 2009. The State of the Birds, United States of America. Washington, D.C.: United States Department of Interior. [http://www.stateofthebirds.org/] (accessed on March 1, 2010).
Steinberg, M. 2010. Avifaunal Research and Geographical Perspectives. The Geographical Review 100(2): iii-iv.
Store, R., and J. Kangas. 2001. Integrating Spatial Multi-Criteria Evaluation and Expert Knowledge for GIS-Based Habitat Suitability Modelling. Landscape and Urban Planning 55 (2):79-93.
Vaughan, J. 2010. The Local Geographies of the Coastal Cactus Wren and the Coastal California Gnatcatcher on Marine Corps Base Camp Pendleton California. San Diego State University, San Diego, CA.
Wiens, J. A. 2010. Climate Change, Birds, and Bases in California. Steppingstones. (Newsletter of the Department of Defense Partners in Flight Program). February, 2-3. [http://www.dodpif.org/downloads/DoDPIF-news_2010-1.pdf]. (accessed February 17, 2010).