Effects of recreational activity on the avian community of green spaces within Sunset Valley, Texas




Tibbets, Mary N.

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The spread of urban and suburban habitats into what were once rural and undeveloped lands has left urban green spaces as refuges for wildlife populations in otherwise inhospitable environments. As human populations grow, so does the use of these green spaces for recreational activities. This study examined the effects of human recreational activities within green spaces on bird populations in Sunset Valley, Texas, an urban/suburban habitat southwest of Austin, Texas. Thirty fixed-radius point count stations were placed on walking trails throughout the city. Each point was visited five times during each of four seasons. I recorded birds seen or heard at each point count station, their distance from the center of the point, the number of recreationists passing through the point count site, and decibel levels at the point for a five minute duration. Vegetation information was taken at each point before and after leaf drop using a vegetation profile board and a densiometer. I used a principal component analysis (PCA) to describe habitat characteristics at each site and a canonical correspondence analysis (CCA) to assess relationships between bird species, habitat, season, area of the study site, and recreational activities. 1 also conducted univariate tests to determine the relationship between urban bird guilds and different habitat and anthropogenic variables. The full model of the CCA explained 44.7% of the observed variation within bird abundances with the pure effects of habitat explaining 26.1 percent of the variation (p = 0.002) and season explaining 2.4 percent (p = 0.002) of the variation. Pure effects of area (0.9%; p = 0.18) and anthropogenic disturbances (4.9%; p = 0.11) were not significant. Univariate parameters significant in the stepwise procedure were mean canopy cover (17%; p = 0.002), mean vertical vegetation cover (6%; p = 0.002), area (5%; p = 0.002), high decibel level (5%; p = 0.002), and percent Ashe juniper cover (2%; p = 0.05). My results indicate that vegetational characteristics are the main factor influencing bird populations in urban/suburban habitats, followed by the mean maximum decibel level at each point. My results also suggest that bird species that are already stressed under urban/suburban environments may be excluded from areas where decibel levels are too high.



bird populations, birds, recreation areas, ornithology


Tibbets, M. N. (2009). Effects of recreational activity on the avian community of green spaces within Sunset Valley, Texas (Unpublished thesis). Texas State University-San Marcos, San Marcos, Texas.


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