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Analyzing Factors Influencing Reproductive Success of the Mountain Chicken : Nordens Ark Captive Breeding ProgramDonaldson, Chad January 2019 (has links)
Amphibians globally are declining with roughly a third facing extinction due primarily to threats linked to human impacts. One way in which this is being combated is by captive breeding programs. Nordens Ark in Sweden, in collaboration with other organizations, is attempting to breed one of the most threatened frogs for future reintroduction to the wild. The mountain chicken (Leptodactylus fallax) has unique characteristics related to its reproduction which make it challenging to breed successful offspring. Using Nordens Ark’s data on environmental conditions within breeding enclosures, this study attempts to determine which extrinsic factors are having the most influence on reproduction, in order to increase the success of the captive breeding program. Multiple linear regression analysis and model simplification using Stepwise regression and Akaike information criterion (AIC) were performed in order to determine which explanatory variables had the most influence in relation to foam nests. A reduced model with significant values for explanatory variables was deemed the best model based on the dataset. Of the 14 environmental variables tested, minimum temperature after nest construction had the most influence on foam nest length. When compared to wild habitats, temperatures within enclosures may be too high or lack seasonal cyclical patterns. Barometric pressure and humidity also had influence on foam nests, but the relationships between these environmental conditions is difficult to parse. Food supplements were also a significant factor and suggest that lack of vitamins or nutrients can have a negative effect on reproductive success. Ensuring the optimal conditions can be difficult for captive breeding programs, especially as amphibians are under-represented and face biases in conservation and research.
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Evaluating the Effects of Road Crossing Structures on Stream-Associated Amphibians in the Wilson River Watershed, Tillamook State Forest, OregonTwitchell, Sara Erin 15 March 2013 (has links)
As replacement and removal of undersized culverts gains momentum as an effective technique for restoring natural stream flows and removing fish passage barriers, it is important to evaluate the benefits of these efforts on the in-stream and adjacent riparian habitat for other species of potential concern. This study compares stream-associated amphibian (SAA) occurrence in streams adjacent to different road crossing structures on unpaved forest roads in the Wilson River watershed located within the Tillamook State Forest, Oregon. Surveys were conducted at road crossing structures for three taxa of SAA; Pacific giant salamander (Dicamptodon tenebrosus), coastal tailed frog (Ascaphus truei), and Columbia torrent salamander (Rhyacotriton kezeri). Statistical models were created to analyze the effect of habitat variables on SAA occupancy, and determine whether those variables changed relative to road crossing structures. Results showed that coastal tailed frog occupancy was positively associated with dissolved oxygen and crayfish presence, negatively associated with longitude, and had a slight quadratic relationship to channel confinement. Because all sites were highly saturated with oxygen, percent dissolved oxygen was likely a surrogate for one or more other covariates, such as in-stream habitat or substrate size. Detection rates of Pacific giant salamander were too high and detection rates of Columbia torrent salamander were too low to provide reliable models, but they did provide some insight into the factors affecting occupancy in the study area, including information about their interactions with road crossing structures. Occupancy rates of Pacific giant salamanders in the study area appear to be unaffected by road crossings, fish passable or otherwise. Conversely, torrent salamanders seemed to be mostly absent from the study sites altogether, but based on the one stream where they were detected, they are not excluded from occupying fish barrier culvert sites. Top weighted habitat covariates, including dissolved oxygen, channel confinement, crayfish and fish presence, and flow constriction are all indicators of disturbance that can be linked to road crossings. Although the size and structure of road crossings did not prove to significantly influence SAA occupancy, indicators of stream disturbance that can be related to road crossings were included in the best models for predicting occupancy, demonstrating the importance of reducing disturbance related to road crossings on streams.
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Ocorrência e distribuição espacial e temporal das larvas de anuros (Amphibia) em diferentes sistemas aquáticos da Ilha Grande (Rio de Janeiro) / Occurrence and spatial and temporal distribution of anuran larvae (Amphibia) in different aquatic systems of Ilha grande (Rio de Janeiro)Pedro Cavalcanti Fatorelli Carneiro 23 February 2011 (has links)
Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro / Os girinos dos anuros podem ocorrer em inúmeros tipos de sistemas hídricos,
desde ambientes relativamente simples e previsíveis, como na água acumulada em
epífitas ou uma poça temporária, até hábitats aquáticos permanentes mais complexos,
como os riachos. A interação entre os fatores ambientais bióticos e abióticos existentes
nesses diferentes ambientes com os fatores históricos é essencial para explicar a
estrutura das comunidades dessa fase de vida dos anuros. O entendimento sobre como
estes fatores atuam e sua importância nos conduz a uma maior compreensão do que
parece influenciar positivamente ou negativamente o estabelecimento dos girinos nos
seus diferentes ambientes. Inicialmente, fornecemos uma discussão detalhada da
importância desses fatores. Em seguida, avaliamos a estrutura da assembléia dos
girinos e a sua estratégia de ocupação espacial e temporal em relação ao uso de
diferentes sistemas aquáticos, temporários e permanentes (poças, terrenos alagados,
riachos e ambientes artificiais) em uma área de Mata Atlântica na Ilha Grande (Rio de
Janeiro). Posteriormente, propomos um experimento para avaliar como os girinos
característicos de diferentes tipos de habitats hídricos respondem à condição adversa
de ausência de água livre. Depois, é sugerida uma chave artificial de identificação para
os girinos da Ilha Grande, com base nas espécies contempladas neste estudo. Por fim,
apresentamos a descrição do girino de Proceratophrys tupinamba, provendo algumas
informações sobre sua distribuição temporal e uso de microhabitats. Registramos
girinos de 12 espécies de anuros, o que correspondeu a 71% dos anfíbios da Ilha
Grande com larvas exotróficas em ambientes aquáticos. O espectro de habitats hídricos
utilizados variou consistentemente entre as espécies. Girinos de Aplastodiscus eugenioi
e Scinax trapicheiroi foram aqueles que utilizaram a maior quantia de tipos de habitats,
ambos com cinco registros. A maioria das espécies teve suas maiores abundâncias em
um ou dois tipos de corpos dágua onde ocorreu, portanto poucas destas espécies
demonstram ter sido generalistas no uso de tipos de habitats aquáticos. A maior riqueza
de espécies ocorreu em poças temporárias, em riachos intermitentes e no ambiente
antropizado da calha artificial. Quando consideramos em termos de habitats hídricos, a
maior riqueza ocorreu nas poças temporárias, nos riachos intermitentes, nos riachos
permanentes e na calha artificial. Em nem todos os meses um determinado tipo de
recurso hídrico manteve a sua riqueza máxima de girinos. Observamos que um mesmo
tipo de sistema hídrico pode comportar espécies típicas de ambientes lênticos e outras
adaptadas a ambientes lóticos, dependendo da estrutura em que o corpo dágua
apresenta naquele período, como os riachos intermitentes, por exemplo. Entre os
fatores abióticos medidos, o PH, o oxigênio dissolvido, a correnteza, a largura e a
profundidade dos corpos dágua explicaram de forma mais importante a ocorrência e
abundância das diferentes espécies de girinos. Portanto, consideramos que fatores
ecológicos desempenham um importante papel na determinação da distribuição de
girinos dentro e entre habitats que estes organismos ocupam. O experimento proposto
mostrou que os tempos de sobrevivência entre as onze espécies contempladas e
também entre os indivíduos de diferentes tamanhos em uma mesma espécie variaram
consideravelmente. Isto é sugestivo de que estas espécies apresentam diferentes
estratégias para tolerar uma condição de independência de água livre. Os fatores que
pareceram mais influenciar negativamente na sobrevivência dos girinos foram: hábito
nectônico, pequeno tamanho dos indivíduos, ocupação de ambientes lênticos e
temporários e modo reprodutivo não-especializado. Alternativamente, os girinos com
melhor desempenho em uma condição de independência de água livre foram de
espécies de tamanho comparativamente grande ou médio, ocuparam preferencialmente
ambientes lóticos e permanentes, apresentaram modos reprodutivos especializados e
os hábitos dos girinos foram principalmente bentônicos. Neste contexto, pode se
conjecturar que os girinos das espécies que utilizam ambientes permanentes sejam
mais resistentes à condição de independência de água livre do que aquelas de habitats
efêmeros. Considerando especial atenção para a biodiversidade dos anfíbios, a Ilha
Grande apresenta uma elevada concentração de espécies endêmicas. Esta respeitável
diversidade de anfíbios para a área estudada está relacionada com a cobertura vegetal
de Mata Atlântica e a grande quantidade de corpos dágua na Ilha, tanto temporários
quanto permanentes. A influência destas condições favoráveis para os anfíbios na
região está demonstrada também na diversidade de modos reprodutivos, onde 13 dos
39 modos reprodutivos já descritos foram notados para os anfíbios da Ilha Grande. Este
conjunto de fatores reafirma esta como uma das mais importantes áreas para a
conservação da biodiversidade de anfíbios para o estado do Rio de Janeiro.
Comparando a descrição do girino de Proceratophrys tupinamba com P. appendiculata,
observamos algumas diferenças na proporção do corpo. Os girinos da espécie descrita
foram mais abundantes durante a estação chuvosa (outubro-março), sendo esta
distribuição positivamente relacionada com a precipitação média mensal. Os girinos são
bentônicos e ocorrem mais frequentemente em porções de menor correnteza do riacho.
Eles foram encontrados com maior freqüência expostos na areia, que também
representou o microhabitat mais disponível entre aqueles no córrego estudado. / Tadpoles can be found in a number of different aquatic habitats, ranging from
relatively simple predictable ecosystems such as bromeliad tank and temporary ponds,
to permanent complex ecosystems like streams and rivers. Knowing about the
interactions between biotic and abiotic within these habitats is crucial to understand how
tadpole communities are structured. Understanding how these factors work and its
importance leads to better discerning of what seems positively or negatively influence
the establishment of tadpoles in their different environments. Initially, we provide a
detailed discussion of the importance of these factors. Next, we evaluate the structure of
the assembly of the tadpoles and their strategy of spatial and temporal occupancy in
relation to the use of different aquatic systems, temporary and permanent (puddles,
flooded land, streams and artificial environments) in an Atlantic Forest area in Ilha
Grande (Rio de Janeiro). Subsequently, we propose an experiment to evaluate how
tadpoles characteristic of different types of water habitats respond to adverse conditions
of absence of free water. Then it is suggested an artificial key to the tadpoles of the Ilha
Grande, based on the species covered in this study. Finally, we present the description
of the tadpoles of Proceratophrys tupinamba, and provide information on its temporal
distribution and microhabitat use. We recorded 12 species of tadpoles, which
corresponded to 71% of amphibians of the Ilha Grande with exotrophic larvae in aquatic
environments. The spectrum of habitats used varied consistently between species.
Tadpoles of Aplastodiscus eugenioi and Scinax trapicheiroi used the greatest amount of
habitat types, both with five records. Most species had their highest abundance in one or
two types of water bodies where it occurred, so few of these species have been
demonstrated to be generalists in the use of aquatic habitats. The highest species
richness was found in temporary ponds, in intermittent streams and anthropic
environment in the artificial gutter. When considered in terms of water habitats, the
richest places were temporary pools, intermittent streams, permanent streams and the
artificial gutter. It was not every month that a certain type of water resource maintained
its maximum richness of tadpoles. We observe that the same type of water system may
include species typical of lentic and lotic environments adapted to other, depending on
the structure in which the water body has at that time, such as intermittent streams, for
example. Among the abiotic factors measured, the pH, dissolved oxygen, the current,
the width and depth of the water bodies more importantly explained the occurrence and
abundance of different species of tadpoles. Therefore, we believe that ecological factors
play an important role in determining the distribution of tadpoles within and among
habitats that these organisms occupy. The proposed experiment showed that the
survival times between covered eleven species and between individuals of different
sizes in the same species varied considerably. This is suggestive that these species
have different strategies to tolerate a condition of independence of free water. The
factors that seemed most negative influence on survival of tadpoles were nektonics
habit, small individual size, occupation of lentic and temporary habitats and nonspecialized
reproductive mode. Alternatively, tadpoles with better performance in a
condition of independence of free water were species comparatively large or medium
size, that occupied mainly permanent lotic habitats, presented specialized reproductive
modes and the tadpoles were mainly benthic. In this context, we can surmise that the
tadpoles of species that use permanent environments are more resistant to the condition
of independence of free water than those of ephemeral habitats. Noting with particular
attention to the biodiversity of amphibians, theIlha Grande has a high concentration of
endemic species. This respectable amphibian diversity in the study area is related to the
canopy of Atlantic Forest and the large amounts of water bodies on the island, both
temporary and permanent. The influence of these favorable conditions for amphibians in
the region is also demonstrated in the diversity of reproductive modes, where 13 of the
39 reproductive modes described were noted for the amphibians of the Ilha Grande.
These factors reaffirm this as one of the most important areas for biodiversity
conservation of amphibians in the state of Rio de Janeiro. Comparing the description of
the tadpole of Proceratophrys tupinamba with P. appendiculata, we observed some
differences in the proportion of the body. Tadpoles of the species described were more
abundant during the rainy season (October to March), this distribution is positively
related to average monthly precipitation. The tadpoles are benthic and occur more often
in lower stream portions of the creek. They were found more frequently exposed in the
sand, which also represented the most microhabitat among those available in the
stream studied.
|
454 |
Ocorrência e distribuição espacial e temporal das larvas de anuros (Amphibia) em diferentes sistemas aquáticos da Ilha Grande (Rio de Janeiro) / Occurrence and spatial and temporal distribution of anuran larvae (Amphibia) in different aquatic systems of Ilha grande (Rio de Janeiro)Pedro Cavalcanti Fatorelli Carneiro 23 February 2011 (has links)
Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro / Os girinos dos anuros podem ocorrer em inúmeros tipos de sistemas hídricos,
desde ambientes relativamente simples e previsíveis, como na água acumulada em
epífitas ou uma poça temporária, até hábitats aquáticos permanentes mais complexos,
como os riachos. A interação entre os fatores ambientais bióticos e abióticos existentes
nesses diferentes ambientes com os fatores históricos é essencial para explicar a
estrutura das comunidades dessa fase de vida dos anuros. O entendimento sobre como
estes fatores atuam e sua importância nos conduz a uma maior compreensão do que
parece influenciar positivamente ou negativamente o estabelecimento dos girinos nos
seus diferentes ambientes. Inicialmente, fornecemos uma discussão detalhada da
importância desses fatores. Em seguida, avaliamos a estrutura da assembléia dos
girinos e a sua estratégia de ocupação espacial e temporal em relação ao uso de
diferentes sistemas aquáticos, temporários e permanentes (poças, terrenos alagados,
riachos e ambientes artificiais) em uma área de Mata Atlântica na Ilha Grande (Rio de
Janeiro). Posteriormente, propomos um experimento para avaliar como os girinos
característicos de diferentes tipos de habitats hídricos respondem à condição adversa
de ausência de água livre. Depois, é sugerida uma chave artificial de identificação para
os girinos da Ilha Grande, com base nas espécies contempladas neste estudo. Por fim,
apresentamos a descrição do girino de Proceratophrys tupinamba, provendo algumas
informações sobre sua distribuição temporal e uso de microhabitats. Registramos
girinos de 12 espécies de anuros, o que correspondeu a 71% dos anfíbios da Ilha
Grande com larvas exotróficas em ambientes aquáticos. O espectro de habitats hídricos
utilizados variou consistentemente entre as espécies. Girinos de Aplastodiscus eugenioi
e Scinax trapicheiroi foram aqueles que utilizaram a maior quantia de tipos de habitats,
ambos com cinco registros. A maioria das espécies teve suas maiores abundâncias em
um ou dois tipos de corpos dágua onde ocorreu, portanto poucas destas espécies
demonstram ter sido generalistas no uso de tipos de habitats aquáticos. A maior riqueza
de espécies ocorreu em poças temporárias, em riachos intermitentes e no ambiente
antropizado da calha artificial. Quando consideramos em termos de habitats hídricos, a
maior riqueza ocorreu nas poças temporárias, nos riachos intermitentes, nos riachos
permanentes e na calha artificial. Em nem todos os meses um determinado tipo de
recurso hídrico manteve a sua riqueza máxima de girinos. Observamos que um mesmo
tipo de sistema hídrico pode comportar espécies típicas de ambientes lênticos e outras
adaptadas a ambientes lóticos, dependendo da estrutura em que o corpo dágua
apresenta naquele período, como os riachos intermitentes, por exemplo. Entre os
fatores abióticos medidos, o PH, o oxigênio dissolvido, a correnteza, a largura e a
profundidade dos corpos dágua explicaram de forma mais importante a ocorrência e
abundância das diferentes espécies de girinos. Portanto, consideramos que fatores
ecológicos desempenham um importante papel na determinação da distribuição de
girinos dentro e entre habitats que estes organismos ocupam. O experimento proposto
mostrou que os tempos de sobrevivência entre as onze espécies contempladas e
também entre os indivíduos de diferentes tamanhos em uma mesma espécie variaram
consideravelmente. Isto é sugestivo de que estas espécies apresentam diferentes
estratégias para tolerar uma condição de independência de água livre. Os fatores que
pareceram mais influenciar negativamente na sobrevivência dos girinos foram: hábito
nectônico, pequeno tamanho dos indivíduos, ocupação de ambientes lênticos e
temporários e modo reprodutivo não-especializado. Alternativamente, os girinos com
melhor desempenho em uma condição de independência de água livre foram de
espécies de tamanho comparativamente grande ou médio, ocuparam preferencialmente
ambientes lóticos e permanentes, apresentaram modos reprodutivos especializados e
os hábitos dos girinos foram principalmente bentônicos. Neste contexto, pode se
conjecturar que os girinos das espécies que utilizam ambientes permanentes sejam
mais resistentes à condição de independência de água livre do que aquelas de habitats
efêmeros. Considerando especial atenção para a biodiversidade dos anfíbios, a Ilha
Grande apresenta uma elevada concentração de espécies endêmicas. Esta respeitável
diversidade de anfíbios para a área estudada está relacionada com a cobertura vegetal
de Mata Atlântica e a grande quantidade de corpos dágua na Ilha, tanto temporários
quanto permanentes. A influência destas condições favoráveis para os anfíbios na
região está demonstrada também na diversidade de modos reprodutivos, onde 13 dos
39 modos reprodutivos já descritos foram notados para os anfíbios da Ilha Grande. Este
conjunto de fatores reafirma esta como uma das mais importantes áreas para a
conservação da biodiversidade de anfíbios para o estado do Rio de Janeiro.
Comparando a descrição do girino de Proceratophrys tupinamba com P. appendiculata,
observamos algumas diferenças na proporção do corpo. Os girinos da espécie descrita
foram mais abundantes durante a estação chuvosa (outubro-março), sendo esta
distribuição positivamente relacionada com a precipitação média mensal. Os girinos são
bentônicos e ocorrem mais frequentemente em porções de menor correnteza do riacho.
Eles foram encontrados com maior freqüência expostos na areia, que também
representou o microhabitat mais disponível entre aqueles no córrego estudado. / Tadpoles can be found in a number of different aquatic habitats, ranging from
relatively simple predictable ecosystems such as bromeliad tank and temporary ponds,
to permanent complex ecosystems like streams and rivers. Knowing about the
interactions between biotic and abiotic within these habitats is crucial to understand how
tadpole communities are structured. Understanding how these factors work and its
importance leads to better discerning of what seems positively or negatively influence
the establishment of tadpoles in their different environments. Initially, we provide a
detailed discussion of the importance of these factors. Next, we evaluate the structure of
the assembly of the tadpoles and their strategy of spatial and temporal occupancy in
relation to the use of different aquatic systems, temporary and permanent (puddles,
flooded land, streams and artificial environments) in an Atlantic Forest area in Ilha
Grande (Rio de Janeiro). Subsequently, we propose an experiment to evaluate how
tadpoles characteristic of different types of water habitats respond to adverse conditions
of absence of free water. Then it is suggested an artificial key to the tadpoles of the Ilha
Grande, based on the species covered in this study. Finally, we present the description
of the tadpoles of Proceratophrys tupinamba, and provide information on its temporal
distribution and microhabitat use. We recorded 12 species of tadpoles, which
corresponded to 71% of amphibians of the Ilha Grande with exotrophic larvae in aquatic
environments. The spectrum of habitats used varied consistently between species.
Tadpoles of Aplastodiscus eugenioi and Scinax trapicheiroi used the greatest amount of
habitat types, both with five records. Most species had their highest abundance in one or
two types of water bodies where it occurred, so few of these species have been
demonstrated to be generalists in the use of aquatic habitats. The highest species
richness was found in temporary ponds, in intermittent streams and anthropic
environment in the artificial gutter. When considered in terms of water habitats, the
richest places were temporary pools, intermittent streams, permanent streams and the
artificial gutter. It was not every month that a certain type of water resource maintained
its maximum richness of tadpoles. We observe that the same type of water system may
include species typical of lentic and lotic environments adapted to other, depending on
the structure in which the water body has at that time, such as intermittent streams, for
example. Among the abiotic factors measured, the pH, dissolved oxygen, the current,
the width and depth of the water bodies more importantly explained the occurrence and
abundance of different species of tadpoles. Therefore, we believe that ecological factors
play an important role in determining the distribution of tadpoles within and among
habitats that these organisms occupy. The proposed experiment showed that the
survival times between covered eleven species and between individuals of different
sizes in the same species varied considerably. This is suggestive that these species
have different strategies to tolerate a condition of independence of free water. The
factors that seemed most negative influence on survival of tadpoles were nektonics
habit, small individual size, occupation of lentic and temporary habitats and nonspecialized
reproductive mode. Alternatively, tadpoles with better performance in a
condition of independence of free water were species comparatively large or medium
size, that occupied mainly permanent lotic habitats, presented specialized reproductive
modes and the tadpoles were mainly benthic. In this context, we can surmise that the
tadpoles of species that use permanent environments are more resistant to the condition
of independence of free water than those of ephemeral habitats. Noting with particular
attention to the biodiversity of amphibians, theIlha Grande has a high concentration of
endemic species. This respectable amphibian diversity in the study area is related to the
canopy of Atlantic Forest and the large amounts of water bodies on the island, both
temporary and permanent. The influence of these favorable conditions for amphibians in
the region is also demonstrated in the diversity of reproductive modes, where 13 of the
39 reproductive modes described were noted for the amphibians of the Ilha Grande.
These factors reaffirm this as one of the most important areas for biodiversity
conservation of amphibians in the state of Rio de Janeiro. Comparing the description of
the tadpole of Proceratophrys tupinamba with P. appendiculata, we observed some
differences in the proportion of the body. Tadpoles of the species described were more
abundant during the rainy season (October to March), this distribution is positively
related to average monthly precipitation. The tadpoles are benthic and occur more often
in lower stream portions of the creek. They were found more frequently exposed in the
sand, which also represented the most microhabitat among those available in the
stream studied.
|
455 |
Avaliação genotóxica e mutagênica de herbicidas em organismos aquáticos / Genotoxic and mutagenic evaluation of herbicides in aquatic organismsCarvalho, Wanessa Fernandes 23 March 2018 (has links)
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Previous issue date: 2018-03-23 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The increased use of pesticides, the risks and disruptions that these compounds can cause to
organisms and the environment has been much discussed in recent years. 2,4-D and glyphosate
herbicides are applied post-emergence in large-scale crops and play an important role in the
optimization of agricultural production worldwide. Environmental quality bioindicators are used in
environmental impact assessment studies because of their interaction with the environment and
their ease of absorption and accumulation of xenobiotic compounds (Younes, 2000). Therefore, the
objective of this study was to evaluate the genotoxic and mutagenic effects of herbicides on
environmental quality bionicators. Acute toxicity of Credit® at 48%, Herbifen Super® at 97%,
Weedar Full® at 83.5%, Dedalo elite® at 30%, and Imazethapyr and their binary combinations
were tested on Cnesterodon decemmaculatus, Rhinella arenarum and Dendropsophus minutus. The
lethal effect was determined from experiments with mortality and the sublethal was used the single
cell gel electrophoresis (SCGE) bioassay and the micronucleus test. The LC5096h value for
Herbifen Super® was 2.668 mg / L, Weedar Full® was 678.04 mg / L, Dedalo elite® was 0.463
mg / L and for Credit® was 91.73 mg / L and Imazethapyr® was 0.99 mg / L. The results of this
study demonstrated that the comet assay and the micronucleus test are highly sensitive methods for
the detection of herbicide-induced DNA damage in aquatic organisms. The herbicides tested
showed different behaviors when combined at their concentrations of 5% and 10% of LC5096h. The
toxic effect of the combination of Herbifen Super® and Credit® was basically due to the action of
the active principle glyphosate present in Credit®. For Weedar Full® and Dedalo elite®
herbicides, synergism was observed in combinations of 5% and 10% of LC5096h values. Our study
is the first report on the induction of lethal acute and sublethal effects of Credit® binary
combinations; Herbifen Super®, Weedar Full®, Dedalo elite®; Imazethapyr® in aquatic
organisms. / O aumento da utilização dos pesticidas, os riscos e perturbações que esses compostos podem
provocar aos organismos e ao meio ambiente está sendo bastante discutido nos últimos anos. Os
herbicidas 2,4-D e glifosato são aplicados em pós-emergência em culturas de larga escala e
desempenham um papel importante na otimização da produção agrícola em todo o mundo. Os
bioindicadores de qualidade ambiental são utilizados em estudos de avaliações de impacto
ambiental devido sua interação com o meio ambiente e a sua facilidade de absorção e acumulação
de compostos xenobióticos (Younes, 2000). Sendo assim, o objetivo deste estudo foi avaliar os
efeitos genotóxicos e mutagênicos de herbicidas em biondicadores de qualidade ambiental. A
toxicidade aguda do Credit® a 48%, Herbifen Super®
a 97%, Weedar Full®
a 83.5%, Dedalo elite®
a 30% e Imazethapyr e suas combinações binárias foram testadas em Cnesterodon
decemmaculatus, Rhinella arenarum e Dendropsophus minutus. O efeito letal foi determinado a
partir de experiências com mortalidade e o subletal foi utilizado o bioensaio de eletroforese em gel
de célula única (SCGE) e oteste do micronúcleo. O valor LC5096h para Herbifen Super®
foi de
2.668 mg / L, Weedar Full®
foi de 678,04 mg/L, Dedalo elite®
foi de 0,463 mg/L e para Credit®
foi de 91.73 mg /L e Imazethapyr®
foi de 0.99 mg/L. Os resultados deste estudo demontraram que
o ensaio cometa e o teste do micronúcleo são métodos altamente sensíveis para a detecção de
danos ao DNA induzidos por herbicidas em organismos aquáticos. Os herbicidas testados
revelaram diferentes comportamentos ao serem combinados em suas concentrações de 5% e 10%
da CL5096h. O efeito tóxico da combinação entre Herbifen Super®
e Credit®
deu-se basicamente
pela ação do princípio ativo glifosato presente no Credit®. Para os herbicidas Weedar Full®
e
Dedalo elite®
foi observado um sinergismo nas combinações de 5% e 10% dos valores de CL5096h.
Nosso estudo constitui o primeiro relatório sobre a indução de efeitos agudos letais e subletal de
combinações binárias de Credit®
; Herbifen Super®
, Weedar Full®
, Dedalo elite®
; Imazethapyr®
em
organismos aquáticos.
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EFFECTS OF FOREST MANAGEMENT ON TERRESTRIAL SALAMANDERS IN A MIDWEST HARDWOOD ECOSYSTEMAlison E Ochs (17118751) 13 October 2023 (has links)
<p dir="ltr">To examine how forest management affects terrestrial salamanders, this dissertation: (1) examines the effects of timber harvesting strategies on salamanders; (2) examines the effects of prescribed fire for oak regeneration on salamander populations; and (3) explores the influence of artificial cover object (ACO) wood type, size and shape, and placement on salamander monitoring results. These projects were conducted at the Hardwood Ecosystem Experiment (HEE) and Martell Experimental Forest in Indiana. Long-term salamander monitoring data from the HEE were used to examine the effects of clearcuts, shelterwoods, and patch cuts on salamander captures collected up to eleven years post-harvest and were analyzed with a before-after-control-impact (BACI) design. Clearcuts and patch cuts had negative effects on salamanders 4-6 years post-harvest, which coincided with a drought; however, preparatory and establishment shelterwood harvests showed no effects on salamander captures, suggesting that retaining canopy cover may protect salamanders from compound disturbances such as drought. Also at the HEE, capture-recapture techniques were used to examine salamander population estimates before and after fire. Only two of three fires affected salamander populations. In the short term, prescribed fire effects on salamanders may be weak and intermittent and microclimate may have a greater effect on populations, although the longer-term effects of fire remain unknown. At Martell Experimental Forest, salamander numbers were compared beneath ACOs of different wood types, sizes and shapes, and grid arrays of different spacings. Pine ACOs were preferred over ash, while several small ACOs yielded equal salamander numbers to one large ACO of equal total area. High ACO density may increase capture probability but reduce the area sampled by each ACO, while lower density ACO grids may cover a larger area with the same sampling effort and produce more comparable results, but with less precision; choice of ACO experimental design will therefore require careful consideration of management goals. This dissertation also suggests strategies to support salamander populations as guidelines for managers to consider in management planning.</p>
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Plant and Herpetofaunal Responses to Wetland Restoration on Pinckney Island National Wildlife Refuge, Beaufort County, South CarolinaClark, Sabrina Diane 05 May 2007 (has links)
Habitat destruction and modification are major causes cited for the decline of amphibians worldwide (Wake and Morowitz 1991). Depressional wetlands on Pinckney Island NWR in Beaufort County, South Carolina were ditched and drained during the 1950?s for agricultural development. Wetlands were restored by filling ditches with existing spoil. I surveyed herpetofaunal and vegetation communities to determine responses to wetland restoration on Pinckney Island from 2004-2005. I selected ten wetlands each in pine and maritime habitats, sampling prior to and after restoration. I recorded 14 reptile and 9 amphibian species using time-constrained searches and funnel trap arrays. I documented (first record on the Island) Fowler?s toad (Bufo woodhousei) and many-lined salamander (Stereochilus marginatus). There were differences between amphibian species richness recorded using time constrained surveys and funnel trap arrays, amphibian species abundance between pine and maritime forest, and between number of Eastern spadefoot toads (Scaphiopus holbrooki) before and after restoration.
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Using Roadkill as a Lens to Understand Animal Movement and MortalityJonaitis, Lauren A. 20 July 2017 (has links)
No description available.
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Spatio-temporal Patterns in Beaver Pond Complexes as Habitat for Eastern Spotted Newts (<i>Notophthalmus viridescens</i>) in a Hemlock-northern-hardwood Zone in Western New York State.Doherty, Shannon Joele January 2015 (has links)
No description available.
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INTERACTIVE AND INDIVIDUAL EFFECTS OF ANTHROPOGENIC ENVIRONMENTAL STRESS ON FRESHWATER ORGANISMSParadyse Blackwood (18953554) 02 July 2024 (has links)
<p dir="ltr">In this dissertation, I explore how human actions (climate change, road salt, land use change, species invasions) interact with and influence morphology, disease, and population dynamics in freshwater organisms (amphibians and aquatic crustaceans). First, I examined how the incidence and timing of disease epidemics in native species (<i>Daphnia dentifera</i>) caused by a generalist parasite (<i>Metschnikowia bicuspidata</i>) influenced the success and impact of an invasive species (<i>Daphnia lumholtzi</i>) in freshwater zooplankton (Chapter 1). In the following chapter, I explored how host-parasite interactions are affected by the interactive effects of multiple environmental stressors, focusing on American bullfrog tadpoles (<i>Lithobates catesbeianus</i>), two of their common parasites (<i>Batrachochytrium dendrobatidis</i> (<i>Bd</i>) and trematode parasites in the family Echinostomatidae), and two common stressors (fluctuating temperatures and sublethal road salt pollution; Chapter 2). Finally, I investigated how the combination of climate (temperature and precipitation) and land use (developed and/or forested area) change have influenced the body size of a common toad (Fowler’s toad, <i>Anaxyrus fowleri</i>) from 1930 – 2020 utilizing museum specimens (Chapter 3). Together, this research establishes how emerging and persistent anthropogenic environmental stressors will interact to affect morphology, disease, and population dynamics in vulnerable freshwater organisms.</p>
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