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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
131

Near infrared reflectance in Anura

Blount, Christopher January 2018 (has links)
Increased near infrared (NIR) reflection, closely resembling the red edge found in leaves, has been known in frogs for many years. Whereas previously thought of as an isolated rarity, we have shown that it is likely far more prevalent than previously believed, occurring in multiple distinct family groups and world regions. To date, there are now 26 anuran species known to demonstrate increased NIR reflectance, from 12 different genera, 4 families, and 3 ecozones. The visible/NIR reflection spectra of each individual measured was found to be characteristic of its species; whether it was wild or captive bred; and its sex. A machine learning based classification system was demonstrated as a viable method of identifying these properties from a frog's reflection spectra alone. How this reflection spectra developed from a pre-metamorphosis froglet through to adult frog was tracked, with the gradual changes to the reflection spectra of both NIR reflective and other frogs identified as being most likely dominated by the reduction in epidermal melanophores, and the increasing number of dermal iridophores. A modified consumer camera was shown to be a viable method for rapid identification of increased NIR reflection in anurans, and was used to identify that salamanders also show variation in NIR reflection between ground dwelling and leaf sitting species. The overnight colour change in Hylomantis lemur was observed, and found to occur pre-emptively of the frog's future location; with the frogs regularly transitioning from pale green ‘daytime' colouration, to the dark brown ‘night time' colouration, while still on the green leaf surface before becoming active, and undertaking the reverse transition while still active, but shortly before returning to the leaf. It seems likely that this change is for protection from silhouetting whilst active. Optical coherence tomography images were taken of several species of frog, and found to be a viable method for non-invasive investigation of anuran skin structure, with structural differences observed between the two colourations of H. lemur. It was found that the most likely cause of the increased NIR reflection in frogs is a reduction in melanin, either by absence or substitution with pterorhodin. Although the true benefit to the frog is difficult to determine, it seems likely that cryptic thermoregulation plays a key role: the maintenance of body temperature for the purpose of camouflage from animals capable of far-infrared vision. This thesis demonstrates the legitimacy of several techniques and approaches for non-invasive study of anurans, but the ultimate scope of the project is fundamentally limited by the range of frogs available. Further insight is likely to arise from increasing this scope, applying these techniques to more frogs, from more species, in more regions, and the author wishes all future researchers the greatest success in this endeavour.
132

Avaliação da qualidade de efluentes na criação de rã-touro (Lithobates catesbeianus)

Borges, Fernanda de Freitas [UNESP] 12 July 2010 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:22:22Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-07-12Bitstream added on 2014-06-13T20:09:25Z : No. of bitstreams: 1 borges_ff_me_jabo.pdf: 2088766 bytes, checksum: 5403ba70f285528d3490e9444e9af9fd (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Universidade Estadual Paulista (UNESP) / O estudo foi realizado no Setor de Ranicultura do Centro de Aquicultura da Universidade Estadual Paulista, Câmpus Jaboticabal/SP em dois períodos distintos, compreendendo uma fase de girinagem e uma fase de engorda no ciclo de criação de rã-touro. Os objetivos foram verificar as características físicas, químicas e microbiológicas da água de entrada e de saída dos tanques em cada fase do ciclo. Os resultados obtidos foram comparados com a legislação ambiental CONAMA 357 de 2005, para verificar se o manejo utilizado em cada fase causa alterações na qualidade da água. Foram analisadas as variáveis temperatura, pH, oxigênio dissolvido, condutividade elétrica, turbidez, nitrogênio amoniacal, nitrato, fósforo total, DBO5, DQO e Escherichia coli em cada etapa do ciclo. O delineamento experimental foi o Inteiramente Casualizado, com dois tratamentos, água de abastecimento e efluente e seis repetições (tanques) em um esquema de parcelas subdivididas, sendo as sub-parcelas as coletas no tempo. As coletas das amostras foram realizadas a cada quinze dias no período da manhã. Na fase de girino o experimento foi realizado entre novembro de 2008 e janeiro de 2009 e teve duração de 76 dias, até os animais completarem a metamorfose. Não foi observada diferença significativa (p>0,05) entre os tratamentos para temperatura, condutividade, turbidez, DQO e E. coli. Entretanto, esses parâmetros variaram nas diferentes coletas. As variáveis pH, oxigênio dissolvido, fósforo total, amônia, nitrato e DBO5 tiveram diferença significativa (p<0,05) entre os tratamentos. Porém, somente as concentrações de fósforo total e DBO5 encontraram-se acima da recomendada pela legislação. A fase de recria teve duração de 77 dias, compreendendo o período de novembro de 2009 a janeiro de 2010, até os animais atingirem o peso de abate. Todas as análises apresentaram diferença significativa... / The study was performed at the frog culture Sector, Aquaculture Center, Sao Paulo State University, Campus Jaboticabal, SP in two different periods, including a tadpole and growout phase in the cycle of creation of the bullfrog. The objectives were to verify the physical, chemical and microbiological water inlet and outlet of the tanks at each stage of the cycle. The results were compared with environmental legislation CONAMA 357, by 2005, to verify whether management used at each stage cause changes in water quality. The variables temperature, pH, dissolved oxygen, electrical conductivity, turbidity, ammonia nitrogen, nitrate, total phosphorus, BOD5, COD and E. coli at each stage of the cycle. The experimental design was completely random, with two treatments, water supply and sewage and six repetitions (tanks) in a split plot, and the sub-plots samples collected over time. The collections of samples were taken fortnightly during the morning. At tadpole phase, the experiment was conducted between November 2008 and January 2009 and lasted 76 days until the animals complete metamorphosis. There was no significant difference (p> 0.05) among treatments for temperature, conductivity, turbidity, COD and E. coli. However, these parameters varied in different samples. The pH, dissolved oxygen, total phosphorus, ammonia, nitrate and BOD5 were significantly different (p<0.05) among treatments. But, only the concentrations of total phosphorus and BOD5 were found above the recommended legislation. The growing phase lasted 77 days, including the period November 2009 to January 2010, until the animals reach slaughter weight. All analysis showed significant differences (p<0.05) among treatments and between collections. The variables, dissolved oxygen, total phosphorus, ammonia, BOD5 and E. coli had their values above those permitted by law... (Complete abstract click electronic access below)
133

Linking Husbandry and Behavior to Enhance Amphibian Reintroduction Success

Linhoff, Luke Jack 22 April 2018 (has links)
Wildlife in captivity has a long history of benefiting global conservation goals. Captive animals can raise awareness and appreciation for the conservation of endangered species. Additionally, captive animals can be used as source populations to reintroduce animals back to the wild or to supplement existing wild populations. The rapid increase in amphibian species threatened with imminent extinction has necessitated the creation of dozens of captive-breeding programs. The focus of this dissertation has integrated topics across the spectrum of animals in captivity and the wild, and the results provide useful recommendations for conservation action. First, I describe how market pressures over a 28-year period are causing meteoric increases in the prices of amphibians sold in the pet trade, indicating a high risk of overexploitation. Pet amphibians may facilitate greater understanding and appreciation of amphibians, but the pet trade must be sustainable. Improving amphibian husbandry will increase the number of captive-bred animals available in the pet trade, and it will allow greater production of threatened species for reintroductions. Secondly, by performing a systematic review of husbandry for 289 amphibian species native to the US, I identified a critical lack in taxon-specific husbandry and developed husbandry research prioritizations. Next, I used a combination of laboratory and field studies to examine domestication processes in amphibians by comparing defensive behaviors in two species of captive-bred and wild poison frog. Captive-bred amphibians had significantly reduced defensive behaviors compared to wild conspecifics, likely resulting from habitation processes related to their husbandry. Finally, I performed three reintroductions of the critically endangered Wyoming Toad (Anaxyrus baxteri) in Wyoming, US. I demonstrated how providing a transitionary period, called a soft-release, to captive-bred toads moving to a novel, wild environment can improve reintroduction success. My work illustrates how improving our understanding of the nexus between captivity and the wild can improve conservation action for endangered species.
134

Altitudinal Variation in the Life History of Anurans in Southeast Queensland

Morrison, Fiona Clare, n/a January 2002 (has links)
Global declines and disappearances of amphibians from high altitude, pristine habitats have been reported in recent years. To date the cause of many of these declines and/or disappearances has not been identified. Although it is well documented that life history characteristics of temperate amphibians are influenced by altitude (due to systematic variation of temperature with altitude), little work has been carried out on the effects of altitude on Australian anurans. This lack of ecological data is a major impediment to identifying the causal factors responsible for amphibian declines. Due to differences in life history characteristics, high altitude populations may be less resilient than their lowland counterparts and subsequently may be more vulnerable to extinction. Consequently, the main aim of this study was to determine whether altitude influenced life history characteristics and ultimately population resilience of anurans in the southeast Queensland region. Six anuran species; Litoria chloris, L. lesueuri, L. pearsoniana (Anura: Hylidae), Mixophyes fasciolatus, M. fleayi and M. iteratus (Anura: Myobatrachidae) were studied over three field seasons (1997-1999) in 18 sites of varying altitude (100-950m) in the southeast Queensland region. The life history characteristics examined were: activity and breeding season length, fecundity and egg size, number of clutches produced per season, tadpole growth and development rates, longevity, age at maturity, reproductive life span, average lifetime fecundity, survival and recapture rates. The data were collected using a combination of field-based surveys (body sizes, clutch sizes, and survival and recapture rates), museum specimen dissections (clutch and egg sizes), reciprocal transplant field experiments (tadpole growth and development rates) and skeletochronology (longevity, age at maturity, reproductive lifespan and average lifetime fecundity). On average, high altitude populations of all species had shorter breeding and activity seasons than low altitude populations (up to 10 weeks less in some cases). The magnitude of the difference in breeding season length varied among years depending on the average temperature and rainfall for the year; i.e. differences appeared greater in warmer and wetter years. Within a population males had longer breeding and activity seasons than females. Although breeding season length varied with altitude, the number of nights that individuals were active within the breeding season did not vary; i.e. low altitude populations were not active for more nights despite having a longer breeding season. This result was attributed to the absence of a relationship between individual activity and environmental variables (air temperature, rainfall, etc.) in many of the populations. Generally, intraspecific clutch size did not vary significantly with altitude. This result was due to the absence of a significant relationship between female body size and altitude (as clutch size is proportional to female body size). Egg size also did not vary with altitude however, suggesting egg size may be canalized (i.e. fixed) in these species. Results also suggest that females of these species only produce one clutch of eggs per season. Interspecific differences in reproductive characteristics largely reflected differences in reproductive mode, larval habitat and female body size. Altitude negatively influenced growth and development rates in L. chloris and development rates in L. pearsoniana. Tadpoles raised at high altitudes were also generally larger at each Gosner Development Stage in both species. The results of the reciprocal transplant experiments suggested that most of the variation in growth and development rates was due to environmental factors (water temperature) rather than genetic or maternal factors. Altitude or genetic factors did not significantly affect tadpole survival in either species. The results suggest that tadpoles occurring at high altitudes take longer to reach metamorphosis and do so at a larger size than their lowland counterparts. With the exception of L. lesueuri, skeletochronology was suitable for age estimation in the study species. Altitude had a significant effect on the age at maturity or longevity in some of the species, however there were trends toward older individuals and older ages at maturity in high altitude populations for the remaining species. Females were generally older than males for all species and in the case of longer-lived species (i.e. Mixophyes spp.) also tended to be older when breeding for the first time. The large overlap of body sizes of individuals of different ages demonstrates that body size is a poor indicator of age in these species. This is the first study to estimate average lifetime fecundity for more than one amphibian species and/or population. The results suggest that the absence of significant altitudinal variation in the average lifetime fecundity of different populations is due to tradeoffs made by females (current reproduction vs. survival). There was no significant altitudinal variation in annual survival and recapture rates in any of the species, and generally there was no difference in the survival and recapture rates of males and females in each population. Within a year, monthly survival and recapture rates were more variable at low than high altitudes and this was attributed to the longer breeding season of low altitude populations. The results did not support previous studies that suggested there was a size bias in survival and recapture rates. The shorter breeding seasons, slower growth and development rates, older age at maturity and greater longevity found in the high altitude study populations will result in increased generation time in those populations. In turn, increased generation time can cause high altitude populations to be less resilient (i.e. population takes longer to return to equilibrium after a disturbance away from equilibrium) (Pimm et al. 1988, Pimm 1991) and ultimately more vulnerable or prone to extinction or decline. The majority of unexplained global amphibian declines have occurred at high altitudes in tropical and subtropical areas. These latitudinal patterns may be explained by the narrow range of environmental tolerances exhibited by tropical organisms resulting in mountains being effectively “higher” in the tropics. Consequently, high altitude tropical species are likely to be even more vulnerable than temperate species occurring at similar altitudes. Further work on the effects of geographic variation, especially interactions between altitude and latitude are needed to evaluate the hypotheses for the causes of these declines and disappearances.
135

The conservation and demography of the Southern Corroboree Frog (Pseudophryne corroboree)

Hunter, David, n/a January 2000 (has links)
The documented decline of amphibian populations over the past two decades has increased attention towards amphibian conservation. Much of this attention has been focused on testing hypotheses as to the causal factors of these declines, however providing convincing data to support any of these hypotheses has proved difficult. The testing of these hypotheses and the implementation of endangered species recovery programs has been restricted by a lack of knowledge of the ecology and population demography of amphibian species that have suffered dramatic declines. This thesis presents aspects of the research phase of the recovery program for the Southern Corroboree Frog, Pseudophryne corroboree, a species that declined to very low numbers during the early 1980's. In particular, this research aimed to determine the distribution, abundance, population dynamics and demography of this rare species. A complete reassessment of the conservation status of P. corroboree was undertaken and the nature of the persistence of this species across the landscape was analysed. Temporal trends in abundance and its relationship with population size were also investigated. Early life-history survivorship and recruitment to metamorphosis were studied at the scale of individual nest sites and populations, and the adult male population age structure and annual mortality were investigated using skeletochronology. The shout/response survey technique was used to survey and monitor the number of breeding male P. corroboree during this study. This method was found to provide consistent results when the surveys were conducted over a short (two week) period during the peak breeding season in January. Neither time of day, nor the number of males present at a pool, was found to influence the level of responsiveness of male P. corroboree to the shout/response technique. Variation in the number of responding males to the shout/response technique through the breeding season, assessed at a single site over two seasons, was unimodal with the peak responding period occurring during the last two weeks of January during both the 1998 and the 1999 breeding seasons. A systematic survey covering 213 sites across the entire historic distribution of P. corroboree found this species to be persisting at 79 sites. The majority of these sites were in the northwestern portion of the species former range, around the Jagungal Wilderness area, while no extant sites were found in the south-eastern portion of the species former range in the Smiggin Holes and Perisher Blue ski resorts area. The overall abundance of males at persistent sites was extremely low, with 92 percent of sites having fewer than ten responding males. Only one site was found to support greater than fifty responding males. A logistic regression analysis found the persistence of P. corroboree to be associated with increased number of pools within a site, decreased distance to nearest extant population and geographic position (latitude and longitude) in the landscape. While annual variation was observed in the number of breeding males for individual sites, there was no overall trend for an increase or decrease in the number of males, regardless of population size. The average annual extinction rate for local populations was five percent during this study, with those populations becoming extinct having very few breeding males (between one and three) during the previous season. Embryonic and tadpole survivorship was monitored for individual nests at three sites across three years. Recruitment to metamorphosis for P. corroboree was characterised by high variation in survivorship between nest sites, populations and years, while overall recruitment for nest sites was skewed towards lower survivorship. Average nest survivorship to metamorphosis across all sites and years was ten percent but the skewed nature of this survivorship meant that the majority of nest sites attained very low or no survivorship. The low proportion of nest sites that did attain high survivorship provided the greatest contribution to overall recruitment. The levels of embryonic and tadpole mortality observed in this study would be providing a considerable contribution to the regulation of current population sizes. The greatest level of early life-history mortality was observed during the late autumn/winter egg and tadpole stage, with high survivorship during the summer and early autumn egg stage and the post-winter tadpole stage. The estimated sex ratio for seven populations, based on the number of eggs within male nest sites, indicated that for most populations, regardless of population size, there was a greater proportion of females to males. In general, the estimated sex ratio of smaller populations showed greater annual variation and had a lower average number of females to males than the single large population. Tadpole surveys conducted across remnant populations during both 1998 and 1999 found recruitment to metamorphosis to be very low for the majority of populations. A third of all populations during both years attained no recruitment to metamorphosis, with those populations that did attain recruitment typically having fewer than 20 tadpoles. While sites with more frogs generally recruited more tadpoles, there was no strong relationship between population size and the number of tadpoles recruited per male at the scale of either pool or site. There was also no significant difference in recruitment levels between the two years. Tadpole surveys across breeding pools within the single large population also found very low tadpole abundance. There was no strong relationship between the number of male frogs at a pool and the number of tadpoles per male and there was no significant difference in tadpole abundance between the two years. Based on the low density of males at pools and sites (typically less than five), and the skewed nature of nest survivorship identified from monitoring individual nest sites, it seems likely that both deterministic and stochastic factors are influencing recruitment levels in remnant populations of P. corroboree. This study determined that adult male P. corroboree could be accurately aged using the technique of skeletochronology, and this technique was used to determine the adult male population age structure for three populations. The results indicated that adult male P. corroboree can reach sexual maturity from metamorphosis in three years, but the majority of individuals take four years. The oldest individual identified in this study was nine years old from metamorphosis. The adult male age structure at the single large site showed very little annual variation, whereas the two smaller populations showed highly pulsed age structures from one year to the next. The size of adult males was found to be a poor predictor of age. Annual adult male survivorship, calculated by following cohorts from one year to the next, was 55 percent. Based on this calculation of annual adult male survivorship, it seems likely that the initial decline in P. corroboree involved increased levels of adult mortality. The results of this study indicate that the persistence of. corroboree in the wild is precarious in the short-term. For this reason, it is recommended that efforts be undertaken to secure this species ex situ. Attempts to increase population numbers in the wild would greatly benefit from determining the factor(s) that have caused the decline in this species, however, failure to do so should not preclude field experimental management aimed at developing technique to increase the size of remnant populations. This is because it is likely that small population stochasticity is contributing to the current regulation of population size and it is possible that the factors that caused the decline in this species cannot be removed from the environment.
136

Effects of exposure to Eurasian Milfoil (Myriophyllum spicatum) on the growth and development of Xenopus laevis and the Columbia spotted frog (Rana Lutriventris)

King, Kimberly L. P., January 2007 (has links) (PDF)
Thesis (M.S. zoology)--Washington State University, December 2007. / Includes bibliographical references (p. 24-26).
137

Novel diagnostic technologies for optical communication systems

Watts, Regan Trevor January 2008 (has links)
The objective of this thesis was to develop novel technologies for measuring the physical characteristics of high-speed pulse trains, for use in performance monitoring applications. This thesis describes the development of three separate techniques that perform measurements in either the time domain, frequency domain or the phase space of the optical signal. The first section investigates phase-sensitive pulse measurement techniques. A high- resolution SHG-FROG apparatus was custom-designed to measure 40GHz RZ pulse trains, from which an operational characterisation of a Mach-Zehnder modulator (MZM) was realised. A numerical model of a nonlinear pulse compressor was developed to compress 40GHz RZ pulses from 8.5ps down to 3.4ps. These pulses were time-division multiplexed to 80GHz, and phase-retrievals of the 80GHz pulse trains were measured. A comparison between the techniques of SHG-FROG and linear spectrogram has been undertaken for 10GHz pulse sources, exposing SHG-FROG's weaknesses at this particular repetition rate. The second section investigates a simple, time-averaged, nonlinear detection technique. Two-photon absorption in a GaAs/InGaAs quantum-well laser diode was used to measure the duty cycle (and by extension, the pulse duration) of a range of pulse sources. This technique was further developed to measure the extinction ratio of NRZ pulse trains. Additionally, the pulse duration of a mode-locked laser source was measured using the nonlinear absorption in a 1-m length of As2Se3 Chalcogenide glass fiber. This demonstrates that the nonlinear properties of this glass may well find application in future instrumentation. The third section investigates the development of an ultra-high resolution swept heterodyne spectrometer. This spectrometer was used to spectrally-distinguish repetitive 8-bit NRZ patterns at 2.5Gbit/s. It was also used to measure the chirp parameter of an X-cut LiNbO3 MZM, revealing a chirp parameter of απ/2 < 0.1 across a modulation band- width of 250-2500MHz. Additionally, the distinctive CW spectrum of a DFB laser diode was measured. Analysis of the measured CW spectrum yielded a linewidth enhancement factor of α≃ 1.8 and also the relative intensity noise of the DFB laser diode.
138

Génération de sources optiques fibrées très hautes cadences et caractérisations de fibres optiques microstructurées en verre de Chalcogénure

Fortier, Coraline 19 January 2011 (has links) (PDF)
Ce mémoire de thèse s'inscrit dans le contexte du projet FUTUR financé par l'ANR et concernant le développement de Fonctions optiqUes pour les Transmissions à très haUt débit dans le Réseau coeur et porte sur la génération de sources optiques fibrées très hautes cadences et la caractérisation de fibres optiques microstructurées en verre de Chalcogénure. A cet effet, nous étudions les caractéristiques linéaires et non-linéaires au sein de fibres microstructurées en verre de chalcogénures conçue et réaliser via différentes collaborations dans le cadre du projet de l'ANR FUTUR. Pour cela un grand nombre de méthodes de caractérisations ont été mises au point donnant une comparaison entre une fibre SMF standard et ces fibres microstructurées chalcogénures. Par exemple, un montage interférométrique pour la mesure de la dispersion chromatique pour échantillon court, ou encore de nombreux banc expérimentaux permettant la caractérisations des propriétés non-linéaires des ces fibres (diffusion Raman, diffusion Brillouin, Coefficient non linéaire Kerr...). La seconde partie de ce mémoire présente la mise au point de méthode de conversion d'un battement sinusoïdal en un train d'impulsions hautement cadencé. Il est montré dans ce manuscrit que cette technique a été exploitée au plus prêt de ses limites, par l'obtention d'impulsions extrêmement courtes et par des débits très élevés. Les trains d'impulsions à très hautes cadences ont été caractérisés par un dispositif expérimental SHG-FROG. Une démonstration de la multiplication du débit par deux a été démontrée par l'effet Talbot.
139

Cytological maps of lampbrush chromosomes of European water frogs (Pelophylax esculentus complex) from the Eastern Ukraine

Dedukh, Dmitry, Mazepa, Glib, Shabanov, Dmitry, Rosanov, Juriy, Litvinchuk, Spartak, Borkin, Leo, Saifitdinova, Alsu, Krasikova, Alla January 2013 (has links)
Background: Hybridogenesis (hemiclonal inheritance) is a kind of clonal reproduction in which hybrids between parental species are reproduced by crossing with one of the parental species. European water frogs (Pelophylax esculentus complex) represent an appropriate model for studying interspecies hybridization, processes of hemiclonal inheritance and polyploidization. P. esculentus complex consists of two parental species, P. ridibundus (the lake frog) and P. lessonae (the pool frog), and their hybridogenetic hybrid - P. esculentus (the edible frog). Parental and hybrid frogs can reproduce syntopically and form hemiclonal population systems. For studying mechanisms underlying the maintenance of water frog population systems it is required to characterize the karyotypes transmitted in gametes of parental and different hybrid animals of both sexes. Results: In order to obtain an instrument for characterization of oocyte karyotypes in hybrid female frogs, we constructed cytological maps of lampbrush chromosomes from oocytes of both parental species originating in Eastern Ukraine. We further identified certain molecular components of chromosomal marker structures and mapped coilin-rich spheres and granules, chromosome associated nucleoli and special loops accumulating splicing factors. We recorded the dissimilarities between P. ridibundus and P. lessonae lampbrush chromosomes in the length of orthologous chromosomes, number and location of marker structures and interstitial (TTAGGG)(n)-repeat sites as well as activity of nucleolus organizer. Satellite repeat RrS1 was mapped in centromere regions of lampbrush chromosomes of the both species. Additionally, we discovered transcripts of RrS1 repeat in oocytes of P. ridibundus and P. lessonae. Moreover, G-rich transcripts of telomere repeat were revealed in association with terminal regions of P. ridibundus and P. lessonae lampbrush chromosomes. Conclusions: The constructed cytological maps of lampbrush chromosomes of P. ridibundus and P. lessonae provide basis to define the type of genome transmitted within individual oocytes of P. esculentus females with different ploidy and from various population systems.
140

The Effects of Recreational Trail Design and Management Decisions on Northern Leopard Frog (Rana pipiens) Populations in an Urban Park

McAllister, Catherine January 2006 (has links)
In addition to their original purpose as recreational areas, urban parks provide important habitats for species living in urban settings. Reconciling recreational and environmental goals is problematic, especially for park planners. RIM Park, in Waterloo, Ontario, is an example of this attempted reconciliation, where planners and managers attempted to conserve herpetofauna in a provincially significant wetland. However, this area includes a paved nature trail used by hikers, in-line skaters and cyclists and is adjacent to a golf course (which lies within the boundaries of the park). Herpetofauna breeding ponds were constructed and a series of culverts and clearspans included in order to provide reptiles and amphibians with safe passage under the trails. My objective was to determine whether these measures have been effective, whether the park sustains a viable population of Northern Leopard Frogs, and what factors influence frog populations in the park. Two spring field seasons involving mark and recapture techniques were attempted to estimate population sizes of Northern Leopard Frogs at RIM Park, as well as control sites. In both seasons, a control site was a cedar swamp 14 km to the west of the park within an Environmentally Sensitive Policy Area in Waterloo city limits affected by housing development and shared trails. Also within Waterloo city limits, a storm water management pond 8 km to the west was added in field season two. In 2005 (field season 1), because there was a serious drought almost no Northern Leopard Frogs were captured at the two sites examined ? RIM Park and the cedar swamp. In 2006, the more "normal" weather conditions revealed that RIM Park had significantly fewer Northern Leopard Frogs than either of the control sites. Given the lack of data in year 1, I compared the 2006 results to seven years of monitoring reports on RIM Park from consultants. The 2006 data were consistent with previous reports of small Northern Leopard Frog populations at RIM Park. Mark and recapture sessions revealed relatively low numbers, with a catch average of 4. 33 (SD = 1. 15). Calculations revealed an estimated population of 23 (SE = 13. 42). The highest number of observed Northern Leopard Frogs ever recorded at the same location in consulting reports is 5. It is likely that the ponds at RIM Park do not support breeding in Northern Leopard Frogs as the only adults caught were late in the season, during the last week of May, and adults likely were transients from the nearby wetlands and uplands. It is possible, given the historical monitoring data, that the Northern Leopard Frogs were long absent from RIM Park because of intensive farming activities that had replaced the wetlands, and that construction of the golf course and trails further precluded colonization. The lack of adult frogs in the breeding ponds and the lack of dead or injured frogs on the trails or golf course support the hypothesis that the trails are not presently causing frog mortality. It is possible that the frogs are avoiding recolonizing the trail and golf course area. It is also likely that the breeding ponds need to be deepened and only then will it be apparent whether the frogs will colonize the ponds, lay eggs, and use the clearspans and culverts. Recommendations include a shift in priorities to put the emphasis on restoration, a discussion of restoration options (including a possible restoration plan), possible improvements in amphibian monitoring techniques (such as reducing the reliance on audio methods), and general suggestions for urban park planning and management.

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