Influence of Human Recreational Activities and Vegetative Characteristics on Waterbird Abundance




Polak, Bobby Joe

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Recreational human activities along waterways may influence the occurrence and abundance of waterbirds. I investigated the possible impacts of recreational activity and vegetative characteristics on the relative abundance of waterbirds along a heavily used river, the San Marcos River, in central Texas. The abundance of waterbirds and human disturbance was estimated by conducting point counts for 20 minutes at 30 randomly determined locations along the San Marcos River. Measurement of riparian characteristics at representative transects along the San Marcos River system were conducted to examine correlations between certain vegetative and aquatic parameters and bird occurrence and abundance using multi-variate statistics. A Principle Component Analysis test was run to analyze the difference between the three a priori reaches of the river, divided by the amount of disturbance present, as well as variance partitioning, a test utilizing the Canonical Correspondence Analysis test. With only 2 percent of the explained variation in the occurrence and abundance of waterbirds coming from human disturbance, out of 25 percent explained in total, its apparent that the birds may have habituated out of necessity and that the river vegetative composition is the major deciding factor in determining bird occurrence and abundance.



waterbirds, human disturbance, recreational activities, riparian characteristics, multivariate analysis


Polak, B. J. (2008). Influence of human recreational activities and vegetative characteristics on waterbird abundance</i> (Unpublished thesis). Texas State University-San Marcos, San Marcos, Texas.


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