Dietary Overview of Hemidactylus turcicus with Possible Implications of Food Partitioning

A stomach content analysis was conducted on Hemidactylus turcicus, the Mediterranean gecko, from 19 April 1990 to 15 October 1990, on the campus of Stephen F. Austin State University, Nacogdoches, Texas. Geckos (N = 167) were placed into four size groups based on snout-vent-length (5 29 mm, 30-39 mm, 40-49 mm, and z 50 mm) and three microhabitat groups based on perch height (those occupying perch sites \u3c 1.52 m, 2 1.52 m to 5 3.05 m, and \u3e 3.05 m). Stomach contents were analyzed and sex, size, and microhabitat groups were compared using Schoener\u27s percent overlap index. Volumetrically, the most important prey items taken were Orthoptera, Lepidoptera, and Isopoda. Geckos of different size groups showed some differences in diet. The greatest difference occurred between the smallest and largest size groups. A significant positive correlation was found between gecko size and prey size (r = 0.24, P = 0.0008). Differences in the diets of geckos inhabiting different microhabitats were very evident. Geckos occupying high perch sites ate more flying prey while geckos at lower perch sites ate more ground-dwelling prey

Activity Level-Predation Risk Tradeoff in a Tadpole Guild: Implications for Community Organization Along the Hydroperiod Gradient

Increasing activity levels permit greater food intake for use towards growth and reproduction, consequently increasing predation risk via increased detection. Larval anurans are models to examine activity level-predation risk tradeoffs, as they occupy a variety of lentic habitats that impose constraints on the distribution and abundance of species. Ephemeral ponds have a low abundance and diversity of predators and as a result tadpole species tend to have high foraging rates for rapid development. Permanent ponds generally possess a greater diversity and abundance of predators and tadpoles inhabiting these locations tend to have low activity rates or chemical defenses to minimize predation risk. The objective of this research was to examine how interspecific variation in activity level and response to predation risk, corresponds to the distributions of tadpole species along the hydroperiod gradient. Furthermore, we examined the intraspecific variation in activity level among the species. We conducted a series of laboratory experiments in which we quantified baseline activity patterns and the change in activity after the addition of a predator or exposure to alarm cues, for 12 species of larval anurans native to East Texas. Species that maintained a high activity level generally occupied ephemeral ponds and species that maintained low activity levels generally occupied permanent ponds. Only one species (Gastrophryne carolinensis) decreased their activity level in the presence of predator cues or conspecific alarm cues. These results highlight this tradeoff can have consequences on the life histories of multiple species, providing insight into how it affects the organization of ecological communities

Ecological correlates of anuran breeding activity and community structure

Multiple ecological factors can simultaneously affect species activity and community structure. The goal of my dissertation was to examine the effects of abiotic factors, biotic factors, and succession on anuran communities. I took a three pronged approach dividing the study into three major chapters. First I focused on abiotic factors that affect anuran breeding activity. I found that weather, rainfall and temperature affect the breeding activity of each species differently, and species in my study area can be placed into 5 different groups based on their association with weather and season: 1) breed within a predictable season (summer) independent of local weather patterns 2) breed opportunistically within a predictable season (summer) dependent on local rainfall 3) breed opportunistically within a predictable season (winter) dependent on local temperature 4) breed opportunistically dependent on local flood level rainfall events and 5) breed opportunistically year round dependent on local temperature in the winter and local rainfall in the summer. In the second part of the study, I created a simulation model of an anuran community using published life history parameters of the anuran species in my study system. Results of the model suggest colonizing ability is important for species with low fecundity and high susceptibility to predation. These early succession species tend to be constrained from later stages of succession by predators. Species that are resistant to predators are generally poor colonizers and tend to arrive late in succession, but once they colonize a pond they tend to persist and recruit successfully. Finally, I explored biotic mechanisms that might be important in structuring anuran communities. I found that with the exception of Rana sphenocephala, anuran species occupying sites with shorter hydroperiods had higher activity rates and were more susceptible to predation. Rana sphenocephala appeared to be better at escaping predation than the other species despite a relatively high activity rate. Examination of published phylogenies indicates R. sphenocephala is derived from a species group that uses permanent water suggesting that R. sphenocephala has retained many anti-predator defenses inherited from its ancestors, even though the species now exploits sites with low predator densities

Effects of urbanization on the occurrence of Batrachochytrium dendrobatidis: do urban environments provide refuge from the amphibian chytrid fungus?

Batrachochytrium dendrobatidis (Bd) is a widespread pathogenic fungus that is known to cause the disease, chytridiomycosis, which can be lethal to many amphibians. We compared occurrence rates on spring peepers (Pseudacris crucifer) in urban and forested breeding sites in eastern Texas, USA. All study sites were at approximately the same latitude and altitude, and samples were collected at the same time of year to isolate differences in Bd infection rates between habitat types. We found significant differences (p\u3c0.001) in the occurrence of Bd between habitats; with dramatically lower rates of occurrence at urban sites (19.5 %), compared to forested sites (62.9 %). The exact reason for the observed differences in the occurrence of Bd is not known, however, we suspect that warmer temperatures or lower population densities and lower species richness at urban sites all could play a role in our results. Our findings suggest that urban environments may provide a refuge for some amphibians from the pathogen

Differential jumping performance in newly metamorphosed Blanchard\u27s cricket frogs, Acris blanchardi (Anura: Hylidae), from fish- and invertebrate-dominated ponds

Organisms that adopt phenotypically plastic anti-predator strategies during larval stages may incur fitness costs later in development. These costs are typically difficult to define in many species. The difficulty of identifying ecological trade-offs may result from experimental comparisons that do not adequately mirror naturally occurring predator-prey relatioships. To examine this, we captured 61 newly metamorphosed Acris blanchardi from ponds dominated either by fish or invertebrate predators. These predators are known to induce alternate phenotypic anti-predator responses at the larval stage. We use jumping performance as a measure of post-metamorphic fitness, and compared the morphological traits and jumping ability of frogs from ponds with and without fish. Frogs from fishless ponds can jump significantly farther than frogs from fish-dominated ponds. Morphological measurements indicated that overall frog size determined differences in jumping ability, with hind-leg length primarily explaining jumping performance. Differences in hind-leg length positively correlated with overall body size, which differed between the two types of ponds and did not result from allometric growth between them. Differences in frog sizes presumably are related to differences in developmental anti-predator morphologies in larvae

Batrachochytrium dendrobatidis Detected in Amphibians from National Forests in Eastern Texas, USA

The amphibian disease chytridiomycosis, caused by the pathogenic fungus Batrachochytrium dendrobatidis (Bd, Longcore et al. 1999), is well known as a major threat to amphibians resulting in mass die-offs and population declines throughout the world (Berger et al. 1998; Blaustein and Keisecker 2002; Daszak et al. 2003; McCallum 2005; Rachowicz et al. 2006). Batrachochytrium dendrobatidis has been detected on amphibians from sites across North America (Ouellet et al. 2005; Woodhams et al. 2008) and appears to be most prevalent in the western and the northeastern United States (Longcore et al. 2007; Schlaepfer et al. 2007). Whereas infected anurans also have been found throughout the southeastern US (Green and Dodd 2007), there have been no reports of Bd from amphibians in eastern Texas, a broad area encompassing 10,000,000 ha. We sampled amphibians for the presence of Bd in four National Forests in eastern Texas (approximately 31°N latitude)

Food for early succession birds: relationships among arthropods, shrub vegetation, and soil

During spring and early summer, shrub- and herbaceous-level vegetation provides nesting and foraging habitat for many shrub-habitat birds. We examined relationships among arthropod biomass and abundance, foliage leaf surface area and weight, vegetation ground cover, soil characteristics, relative humidity, and temperature to evaluate what factors may influence arthropod food resources for birds. Relative humidity was inversely associated with arthropod biomass; as humidity increased biomass decreased (r = -0.44, P = 0.004). We failed to detect any relationships between deciduous foliage (surface area and weight) and arthropod biomass or abundance. However, both arthropod abundance (r = 0.30, P = 0.06) and biomass (r = 0.39, P = 0.01) were positively associated with the percentage of herbaceous ground cover. Arthropod abundance also appeared to be positively associated with the percentage of clay in the soil and negatively associated with the percentage of sand. Herbaceous layer vegetation (forbs and grasses) is known to be positively associated with fire frequency suggesting a possible foraging benefit for birds during spring in habitats that are frequently burned. Management of early and late succession pine forest habitat to produce and maintain a healthy herbaceous layer will likely support more arthropods and provide quality foraging habitat for birds

Caracterización de las organizaciones del deporte, recreación y actividad física en materia del fortalecimiento, promoción y posicionamiento como aporte teórico para la planeación y formulación de política pública del municipio de la Virginia, 2012

El municipio de la Virginia, Risaralda se encuentra en el proceso de formulación de una política pública de deporte, recreación y actividad física, que sirva como lineamiento a las administraciones presentes y futuras en la formulación de planes de desarrollo que obedezcan a las necesidades actuales de la comunidad en general. Para tal fin se hace necesario un diagnostico descriptivo de las situación y tendencias actuales en las organizaciones que prestan servicios deportivos, recreativos y de actividad física en el municipio. Para la utilización de este estudio se utilizó una metodología descriptiva creada y avalada por docentes del Programa Ciencias del Deporte y la Recreación, de la Universidad Tecnológica de Pereira, del grupo de Investigación GIGEDE que permitió conocer los aspectos mencionados anteriormente. Los datos recogidos fueron digitalizados mediante el diseño de una hoja de cálculo de Excel, en la cual se tabuló la información recolectada mediante encuestas y se calcularon los resultados basados en lógicas programadas en la hoja de cálculo. En este trabajo se abordó la totalidad de las organizaciones, ya que el universo era muy pequeño, se tomaron 38 organizaciones, (18 juntas de acción comunal, 4 gimnasios, 8 clubes deportivos y 4 centros de actividad física). Con la presente investigación se logró construir una base teórica para la implementación futura de planes de desarrollo destinados al fortalecimiento del sector en el municipio.The municipality of Virginia, Risaralda is in the process of formulating public policy for sport, recreation and physical activity, to serve as a guideline to present and future administrations in formulating development plans which respond to the current needs of the wider community. To this end it is necessary a descriptive diagnosis of the current status and trends in service organizations for sports, recreation and physical activity in the municipality. To use this study used a descriptive methodology created and supported by teachers under the Sports Science and Recreation, Technological University of Pereira, GIGEDE Research group yielded information on the above issues. The collected data were digitized by designing an Excel spreadsheet, which was tabulated the information gathered through surveys and the results were calculated based on programmed logic in the spreadsheet. In this paper sample is not taken, as the universe was very small, it took 38 organizations, 18 community action boards, 4 gyms, sports clubs and 4 8 fitness centers. With the present investigation was able to build a theoretical basis for the future implementation of development plans aimed at strengthening the sector in the municipality

Population Trends of Red-Cockaded Woodpeckers in Texas

We tracked population trends of Red-cockaded Woodpeckers (Picoides borealis) in eastern Texas from 1983 through 2004. After declining precipitously during the 1980s, woodpecker population trends on federal lands (National Forests and Grasslands in Texas, but excluding the Big Thicket National Preserve) increased between 1990 and 2000, and have been stable to slightly decreasing over the past four years. Litigation against the U.S. Forest Service in the mid 1980s reversed a severe population decline, whereas litigation during the past 8 years hampered recovery efforts for the Red-cockaded Woodpecker. Red-cockaded Woodpecker populations on private and State of Texas lands have steadily declined over he past 15 years, most likely the result of demographic isolation. Limited availability of old pines suitable for cavity excavation, inadequate fire regimes to control hardwood midstory, and demographic dysfunction resulting from woodpecker group isolation remain as significant obstacles to recovery in most populations

The Red-cockaded Woodpecker: Interactions With Fire, Snags, Fungi, Rat Snakes, and Pileated Woodpeckers

Red-cockaded woodpecker (Picoides borealis) adaptation to fire-maintained southern pine ecosystems has involved several important interactions: (I) the reduction of hardwood frequency in the pine ecosystem because of frequent tires, (2) the softening of pine heartwood by red heart fungus (Phellinus pini) that hastens cavity excavation by the species, (3) the woodpecker\u27s use of the pine\u27s resin system to create abarrier against rat snakes (Elaphe sp.), and (4) the woodpecker as a keystone cavity excavator for secondary-cavity users. Historically, frequent, low-intensity ground tires in southern pine uplands reduced the availability of dead trees (snags) that are typically used by other woodpecker species for cavity excavation. Behavioral adaptation has permitted red-cockaded woodpeckers to use living pines for their cavity trees and thus exploit the frequently burned pine uplands. Further, it is proposed that recent observations of pileated woodpecker (Dryocopus pileatus) destruction of red-cockaded woodpecker cavities may be related to the exclusion of fire, which has increased the number of snags and pileated woodpeckers. Red-cockaded woodpeckers mostly depend on recl heart fungus to soften the heartwood of their cavity trees, allowing cavity excavation to proceed more quickly. Red-cockaded woodpeckers use the cavity tree\u27s resin system to create a barrier that serves as a deterrent against rat snake predation by excavating small wounds, termed resin wells, above and below cavity entrances. It is suggested that red-cockaded woodpeckers are a keystone species in fire-maintained southern pine ecosystems because, historically, they were the only species that regularly could excavate cavities in living pines within these ecosystems. Many of the more than 30 vertebrate and invertebrate species known to use red-cockaded woodpecker cavities are highly dependent on this woodpecker in fire-maintained upland pine forests