Behavioral adaptation has permitted red-cockaded woodpeckers to use living pines for their cavity trees and thus exploit the frequently burned pine uplands. Historically, frequent, low-intensity ground fires in southern pine uplands reduced the availability of dead trees (snags) that are typically used by other woodpecker species for cavity excavation. Red-cockaded woodpecker (Picoides borealis) adaptation to fire-maintained southern pine ecosystems has involved several important interactions: (1) the reduction of hardwood frequency in the pine ecosystem because of frequent fires, (2) the softening of pine heartwood by red heart fungus (Phellinus pini) that hastens cavity excavation by the species, (3) the woodpecker's use of the pine's resin system to create a barrier against rat snakes (Elaphe sp.), and (4) the woodpecker as a keystone cavity excavator for secondary-cavity users. University of Texas at Austin, University of Texas - Pan American, Texas Parks and Wildlife Department Civil, Architectural, and Environmental Engineering Over 40 percent of the remaining primary freshwater species are of conservation concern and in some need of protection. georgei (San Marcos gambusia) are apparently extinct, and four, Hybognathus amarus (Rio Grande silvery minnow), Notropis simus pecosensis (Pecos bluntnose shiner), Oncorhynchus clarki virginalis (Rio Grande cutthroat trout) and Gambusia senilis (blotched gambusia) appear to be extirpated from the state. simus simus (Rio Grande bluntnose shiner), Gambusia amistadensis (Amistad gambusia) and G.
Of the native fishes originally found in Texas, five taxa, Cyprinella lutrensis blairi (Maravillas red shiner), Notropis orca (phantom shiner), N. We report on the distribution and status of these fishes and provide a key to their identification. Forty-nine families and 268 species of fishes are known to inhabit the freshwaters of Texas.
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