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This study examined the acid-base and ionoregulatory responses by the skin and kidney of adult bullfrogs (Rana catesbiana) during recovery from non-respiratory acidoses. Acidosis was induced by intravascular infusions of HCl (3,000 uequiv/kg), or NH4Cl (4,000 uequiv/kg), or by 45 min enforced submergence. Infused acids were immediately buffered by the extracellular fluids (ECF) and moved rapidly into the intracellular compartment. Clearance of the acid load was slow (> 24 h post-infusion) and only in NH4Cl loaded frogs was the full amount cleared within 5 days. Excess acid was excreted primarily by increased renal NH4+ effluxes. The skin contributed very little to the net acid excretion; instead large "base" losses ("acid" uptake) occurred. Acid infusions also resulted in large ion losses and elevated water uptake across the skin, with electrolytes and water moving down chemical gradients. Frogs infused with HCl died within 96 h; NH4Cl loaded frogs all survived.Forced submergence resulted in a severe lactacidosis which was corrected in 12 h by a combination of renal/cutaneous acid excretion (9:1 ratio) and metabolic utilization of lactate and H+ (~ 95% of excess acid load). Acid excretion occurred primarily as NH4+ efflux by the kidney and skin. A 1:1 exchange of Na+ influx/NH4+, efflux across the skin was found (r = 0.94; P < 0.01) when Jin Na+ was elevated over basal levels (30-40 uequiv/kg·h). Lactate and net acid effluxes by the skin and kidney diminished by 24 h post-disturbance and accounted for 4 to 6% of the total estimated load to the animal. All frogs survived the diving protocol. Restoration of acid-base state in acidotic bullfrogs by ECF and non-ECF mechanisms, as well as the renal and cutaneous responses to the acidosis, is discussed and compared to that of other vertebrates. It is concluded that anurans, and the bullfrog in particular, are poor regulators of acid-base state but instead are very tolerant to marked disturbances of acid-base balance. / Thesis / Master of Science (MS)

Globally, amphibian species have been in decline and a wide range of factors have been purported to be driving the decline. The Gulf Coastal Plain of Florida has a high degree of endemism and rarity and the biodiversity in the region includes a diverse suite of amphibian species. Degradation of habitat has been considered by many to be a major part of amphibian declines, however amphibian declines are complex and in many cases multiple factors are occurring in concert. My dissertation research examined aspects of habitat ecology and occupancy for two rare amphibians, Florida Bog Frog (Rana okaloosae) (Chapter 1, 2, and 3) and Reticulated Flatwoods Salamander (Ambystoma bishopi) (Chapter 5), that are both restricted to the Northern Gulf Coastal Plain. Further, for R. okaloosae I examined the influence of a sympatric congener, Bronze Frog (R. clamitans clamitans), on microhabitat selection (Chapter 1) and growth of tadpoles (Chapter 4). My overall goal was to be able to elucidate factors that limit the geographic range of R. okaloosae and A. bishopi and to identify habitat characteristics that managers could maintain or create to conserve or increase populations of these species. My first chapter examined the microhabitat relationships between R. okaloosae and R. c. clamitans. Rana okaloosae is endemic to northwestern Florida and is sympatric with R. c. clamitans, a more common and widely distributed congener. Further, the two species appeared to be syntopic, have overlapping breeding seasons, and are known to hybridize. The objectives of this chapter were to assess the microhabitat selection of both species and to assess differences in microhabitat use of males of both species during the breeding season. My modeling of habitat selection and comparison of variables used by each species suggests that males of these species select different resources when calling. Therefore, these sympatric ranids select for different resources at a fine scale, however there does appear to be some overlap among some selected habitat characteristics. In Chapter 2, I assessed the habitat use of R. okaloosae at multiple spatial scales. I surveyed for R. okaloosae and evaluated habitat characteristics at used sites and sites where I had no detections to develop among- and within-stream habitat models for R. okaloosae. Rana okaloosae used habitats with high amounts of emergent vegetation at both the among-stream scale and the within-stream scale. Emergent vegetation appears frequently in models of anuran habitat selection, particularly those that occur in fire-dominated landscapes. Further understanding the habitat requirements of R. okaloosae will allow land managers to use appropriate management activities (e.g., prescribed fire) that will increase emergent vegetation and potentially restore habitat that may help increase populations of R. okaloosae. In Chapter 3, I conducted aural surveys for R. okaloosae at two different spatial scales: range-wide and stream-level scales to understand how occupancy and colonization of R. okaloosae may be influenced by scale. My results suggest that at both spatial scales occupancy of R. okaloosae was best described by the presence of mixed forest wetlands at survey sites. At the range-wide scale, colonization and detection were constant across years, however, at the stream-level scale, colonization was predicted by the number of years since last fire and detection was best predicted by the additive combination of relative humidity and temperature. Occupancy of R. okaloosae was patchy at the range-wide and at the stream-level scales and colonization was low at both scales, while derived estimates of local extinction were moderately high. While R. okaloosae still occur in 3 watersheds where they were initially observed in the 1980's, one of the three watersheds appears to be very isolated and detections there are becoming very infrequent. In Chapter 4, I experimentally evaluated the effects of R. c. clamitans tadpoles on R. okaloosae tadpoles. My results suggest that there was limited influence of R. c. clamitans on R. okaloosae. Conversely, it appeared that Rana c. clamitans was more susceptible to intraspecific competition than interspecific competition. The lack of a strong competitive effect of Rana c. clamitans on Rana okaloosae suggests that competitive interactions among tadpoles may have a limited effect at the densities I examined. In Chapter 5, our objectives were to evaluate a suite of within-pool factors (i.e., vegetation structure, water level, and an index to presence of fish) that could influence occupancy of breeding wetlands by larval flatwoods salamanders on Eglin Air Force Base in Florida, USA. Site occupancy over a 4 year period was best described by a model that incorporated high herbaceous vegetation cover and open canopy cover. Detection probability was assessed, but it varied among years and was not included in the model. Our study suggests that managing the breeding habitat of flatwoods salamander for open canopies and dense herbaceous vegetation may contribute to this species' recovery. In conclusion, Chapters 1-3 of my dissertation contribute to a growing understanding about the habitat ecology of R. okaloosae. I have evaluated habitat use of R. okaloosae at multiple spatial scales. At the finest spatial scale R. okaloosae selected for sites that had an abundance of cover probably decreasing their risk of predation (Chapter 1). Similarly, in Chapter 2 at two spatial scales, among and within-streams, R. okaloosae selected for emergent vegetation. Finally, at the broadest spatial scale, range-wide, R. okaloosae were found to be associated with mixed forest wetlands (Chapter 3). I did not find strong support for competition between R. okaloosae and R. c. clamitans tadpoles, although there was some evidence of asymmetric competition (Chapter 4). Further, adult males of each species did not select the same habitat characteristics for calling sites, so there appeared to be some resource partitioning (Chapter 1). Finally, the presence of A. bishopi larvae was found to be associated with herbaceous vegetation and moderate amounts of canopy cover (Chapter 5). Results from Chapter 2 and 5 suggest that both R. okaloosae and A. bishopi are associated with habitat conditions that are likely a result of fire penetrating wetland areas. / Ph. D.

<p>During the last decades many amphibian species and populations have experienced declines and extinctions in different parts of the world. Anthropogenic activities are believed to account for these declines, and one of the hypothesized causes has been the increased level of ultraviolet-B (UV-B) radiation due to depletion of the stratospheric ozone layer. </p><p>Although negative effects of UV-B radiation on development of many amphibian species have been demonstrated, a number of potentially critical issues around assessment of amphibian UV-B radiation tolerance have remained unexplored. For instance, next to nothing is known about geographic variation in UV-B tolerance and about possible carry-over effects of early UV-B exposure to later life-stages. Likewise, synergistic effects with other stressors, as well as sublethal effects on growth have received little attention. </p><p>The results from field and laboratory experiments show that <i>R. temporaria</i> and <i>R. arvalis</i> are relatively tolerant to even high levels of UV-B in terms of embryonic survival. However, it was found that even normal levels of UV-B can reduce early embryonic growth. In addition, the effects of early exposure to UV-B became manifested mostly or only after a considerable time-lag (i.e. at metamorphosis). Furthermore, it was found that the sublethal effects of UV-B may become manifested only in combination with other stressors, such as low pH, and this synergism may differ among different populations. No evidence for genetic differentiation in UV-B tolerance was found.</p><p>These findings suggest that even a relatively tolerant species, such as <i>R. temporaria</i>, may be sensitive to increased levels of UV-B radiation, but that this sensitivity may be highly population, environment and trait dependent. The observed carry-over effects over life-stages emphasise the importance of the early life environment on later life fitness.</p>

During the last decades many amphibian species and populations have experienced declines and extinctions in different parts of the world. Anthropogenic activities are believed to account for these declines, and one of the hypothesized causes has been the increased level of ultraviolet-B (UV-B) radiation due to depletion of the stratospheric ozone layer. Although negative effects of UV-B radiation on development of many amphibian species have been demonstrated, a number of potentially critical issues around assessment of amphibian UV-B radiation tolerance have remained unexplored. For instance, next to nothing is known about geographic variation in UV-B tolerance and about possible carry-over effects of early UV-B exposure to later life-stages. Likewise, synergistic effects with other stressors, as well as sublethal effects on growth have received little attention. The results from field and laboratory experiments show that R. temporaria and R. arvalis are relatively tolerant to even high levels of UV-B in terms of embryonic survival. However, it was found that even normal levels of UV-B can reduce early embryonic growth. In addition, the effects of early exposure to UV-B became manifested mostly or only after a considerable time-lag (i.e. at metamorphosis). Furthermore, it was found that the sublethal effects of UV-B may become manifested only in combination with other stressors, such as low pH, and this synergism may differ among different populations. No evidence for genetic differentiation in UV-B tolerance was found. These findings suggest that even a relatively tolerant species, such as R. temporaria, may be sensitive to increased levels of UV-B radiation, but that this sensitivity may be highly population, environment and trait dependent. The observed carry-over effects over life-stages emphasise the importance of the early life environment on later life fitness.

La dispersion des animaux est un processus clé pour le maintien des populations et métapopulations. En particulier, les amphibiens se déplacent beaucoup durant leur cycle de vie fait de migrations saisonnières. Ceci les rend sensibles à la structure du paysage. En effet, les modifications anthropiques comme l’aménagement d’infrastructures linéaires peuvent constituer des barrières écologiques pour les animaux et limiter le flux de gènes dans le paysage. Si les effets des routes et des lignes chemins de fer sur les déplacements des animaux ont été largement étudiés, les effets des infrastructures liées aux activités de sport d’hiver comme les pistes de ski et les remontées mécaniques sont moins bien connus. Ainsi, la perméabilité des milieux de montagne anthropisés est peu connue. Cette thèse vise à quantifier la perméabilité écologique (ou connectivité fonctionnelle), des domaines skiables pour un amphibien de montagne largement répandu : la Grenouille rousse (Rana temporaria Linnaeus 1758). Pour ce faire, nous combinons un suivi individuel de déplacements et une étude de génétique du paysage pour mieux comprendre les facteurs influençant les déplacements de grenouilles et les flux de gènes dans le paysage. Le suivi individuel est réalisé au moyen de balises GPS et d’analyses de sélection de pas (step selection analysis). L’étude de génétique du paysage est réalisée en prélevant des échantillons d’ADN dans trois domaines skiables de Savoie ainsi que dans une zone témoin située dans le Parc national de la Vanoise. Nous avons testé l’influence de plusieurs variables paysagères liées à la topographie (pente, altitude…), les habitats (réseau de zones humides, couverture du sol…) ou les activités humaines (présence de routes, de pistes de ski) sur le flux de gènes. En utilisant une nouvelle méthode d’optimisation de surface de résistance, nous montrons l’importance du réseau de zones humides pour les amphibiens de montagne. D’une part, elles servent d’habitat préférentiel et d’autre part, un réseau dense de zones humides permet d’assurer une bonne connectivité des paysages pour la Grenouille rousse. Nous mettons également en évidence que l’hétérogénéité des tailles efficaces de populations dans un paysage peut fausser les distances génétiques mesurées entre populations et nous recommandons l’utilisation de techniques pour s’affranchir de tels problèmes. Nos travaux sont importants dans une perspective de gestion durable des domaines skiables, l’aménagement de pistes de ski ou autres infrastructures de loisir pouvant être accompagnée de destructions de zones humides. / Animal disperal is a key process for maintaining populations and metapopulations. In particular, amphibians move a lot during their life cycle made of seasonal migrations. This makes them sensitive to the structure of the landscape. Indeed, anthropogenic changes such as linear infrastructure can act as ecological barriers for animals and limit gene flow within the landscape. While the effects of roads and railways on animal movements have been widely studied, the effects of infrastructure related to winter sports activities such as ski slopes and lifts are less well known. Thus, the permeability of anthropized mountain environments is little known. This thesis aims to quantify the ecological permeability (or functional connectivity) of ski areas for a widely distributed mountain amphibian: the European common frog (Rana temporaria Linnaeus 1758). To do this, we combine individual movement tracking and landscape genetics studies to better understand the factors influencing frog movements and gene flow within the landscape. Individual tracking is carried out by means of GPS tags and step selection analysis. The landscape genetics study is carried out by gathering DNA samples from three ski areas in Savoie and a control area located in the Vanoise National Park. We tested the influence of several landscape variables related to topography (slope, altitude...), habitats (wetland network, land cover...) or human activities (presence of roads, ski slopes) on gene flow. By using a new method of resistance surface optimization, we show the importance of the wetland network for mountain amphibians. On the one hand, they serve as preferential habitat and, on the other hand, a dense network of wetlands ensures good landscape connectivity for the Common frog. We also highlight that the heterogeneity in effective population sizes in a landscape can distort the genetic distances measured between populations and we recommend the use of techniques to overcome such problems. Our work is important for the sustainable management of ski areas, the development of ski slopes or other recreational infrastructure that can be accompanied by the destruction of wetlands.

<p>Period rane laktacije odlikuje se nagatvnim energetskim bilansom i stanjem metaboličkog stresa. Ovakvo stanje nastaje kao posledica smanjenog unosa hrane, porođaja i započinjanja laktacije. Usled negativnog energetskog bilansa organizam povećano tro&scaron;i sopstvene reserve I ulazi u fazu katabolizma. Cilj ove disertacije je da se ispita metabolička, hematolo&scaron;ka, celularna i proizvodna adaptacija krava u funkciji delovanja anaboličkih i kataboličkih indikatora stresa. Katabolički indikatori stresa su: neesterifikovane masne kiseline (čija koncentracija raste kao posledica povećane lipidne mobilizacije) i kortizol (čija vrednost raste usled stresa tokom porođaja). Anabolički indikatori su: insulin (anabolički hormone u organizmu sisara) i IGF-I (indikator anaboličkog delovanja STH). Krave su klasifikovane na osnovu pojedinačnog i kombinovanog delovanja anaboličkih i kataboličkih indikatora stresa. Upotreba četiri odabrana indikatora metaboličkog stresa (insulin, IGF-I, NEFA i kortizol) u prvoj nedelji posle teljenja može pomoći u analizi metaboličkog stresa i produktivnosti krava, &scaron;to se zaključuje na osnovu delovanja indikatora<br />Created by Simpo PDF Creator Pro (unregistered version) http://www.simpopdf.com<br />c<br />stresa na metabolički profil, krvnu sliku, imunolo&scaron;ke i celularne parametre, telesnu kondiciju, proizvodnju mleka i reproduktivnu efikasnost krava. Vrednosti anaboličkih i kataboličkih indikatora se mogu koristiti samostalno ili u kombinaciji, a najbolju mogućnost procene daje upotreba NEFA bilo da se radi o pojedinačnoj ili kombinovanoj upotrebi indikatora.Određivanjem koncentracije navedena četiri indikatora metaboličkog stresa u prvoj nedelji posle teljenja možemo predvideti karakter metabolizma, dubinu metaboličkog stresa i proizvodnju krava u laktaciji koja sledi.</p> / <p>Early lactation period is characterized by negative energy balance and metabolic stress condition. This situation arises as a consequence of reduced food intake, birth and initiation of lactation. Due to negative energy balance increased body using own reserves and is entering to a phase of catabolism. The goal of this dissertation is to examine the metabolic, hematologic, and cellular adaptation of cows in production function and anabolic activity of catabolic stress indicators. Catabolic stress indicators are nonesterified fatty acids - NEFA (whose concentration increases as a result of increased lipid mobilization) and cortisol (the value of which increases due to stress during labor). Anabolic indicators were: insulin (anabolic hormones in mammals) and IGF-I (an indicator of anabolic activity STH). Cows were classified on the basis of individual and combined effects of anabolic and catabolic stress indicators. Using the four selected indicators of metabolic stress (insulin, IGF-I, NEFA and cortisol) in the first week after calving can help in the analysis of metabolic stress and productivity of cows, which<br />Created by Simpo PDF Creator Pro (unregistered version) http://www.simpopdf.com<br />f<br />concludes on the basis of indicators of stress effects on metabolic profile, blood count, and cellular immune parameters, body condition, milk production and reproductive efficiency of cows. Anabolic and catabolic values of indicators may be used singly or in combination, and provides the best opportunity to assess the use of NEFA either a single or combined use of indicators. It is possible to use concentrations of the four indicators of metabolic stress in the first week after calving predict the nature of metabolism, metabolic stress and depth of production in cows in the next lactation.</p>

<p>For ectotherms living in seasonal environments, time available for development and growth is often constrained by the length of the growth season. Declining season length towards higher latitudes often select for latitudinal clines in development and growth rates, exhibiting increasing growth and developmental rates towards the north. However, the physiological and ecological factors enabling these clines are poorly understood.</p><p>Our study system included eight populations of <i>Rana temporaria</i> along a 1500 km latitudinal gradient. We found increased growth rates in populations at higher latitudes to be the result of higher growth efficiency, partly due to increased relative gut length. Populations with higher growth rates also exhibited lower standard metabolic rates, implying that fast-growing individuals are able to achieve high growth rates by spending less energy on maintenance metabolism under low activity conditions.</p><p>Predator densities, and antipredatory defenses in prey, are assumed to decrease towards higher latitudes. While all study populations responded to predator presence by decreasing activity and foraging, high latitude populations maintained higher activity levels in the presence of the predator. In trials with a free-ranging predator, high latitude tadpoles experienced higher mortality than those from the low latitudes. The higher activity level in the northern populations increases mortality under predation risk, but is probably needed to maintain high growth and development rates.</p><p>When competing over resources, tadpoles from the low latitude population were inferior competitors, as indicated by their longer development time when raised together with high latitude tadpoles. We found no effect of latitude on size-corrected burst speed. The general effect of predator presence on burst speed depended on food availability, with well fed tadpoles being faster in the absence, and food restricted being faster in the presence of a predator.</p>

The Caspian region and specifically the Apsheron peninsula of Azerbaijan is known to be polluted with a variety of environmental contaminants, making risk assessment difficult. The wetlands of Sumgayit contain particularly complex mixtures of contaminants. Flow cytometry and the micronucleus assay were used to assess chromosomal damage in aquatic turtles and frogs inhabiting contaminated wetlands in Azerbaijan. By evaluating biomarkers that are indicative of somatic effects, elevated chromosomal damage was documented at several sites in Azerbaijan relative to reference sites. Sediment samples were analyzed for polycyclic aromatic hydrocarbons (PAHs), organochlorines (OCs), and mercury to evaluate contaminant associations with genetic damage. Sediment samples revealed heterogeneous patterns of PAH and mercury concentrations throughout Sumgayit. Significant positive correlations were documented between both PAH and mercury sediment concentrations and chromosomal damage. Population genetic methods were employed to study the effects of long-term chronic contaminant exposure in marsh frogs from Sumgayit. The Sumgayit region has reduced levels of genetic diversity, likely due to environmental degradation. One of the most contaminated sites in Sumgayit, WTP, appears to be a source of new mutations as a result of an increased mutation rate. Finally, the Sumgayit region seems to act as an ecological sink, with levels of gene flow into the region exceeding gene flow out of the region. This study provides not only exposure and biomarker data, but also an integrated method for assessing the cumulative population impacts of contaminant exposure by studying both population genetic and evolutionary effects. The results presented here will be used in conjunction with those of ongoing research involving both wildlife and humans to develop comprehensive ecological and human risk assessments.