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INVESTIGATIONS IN CRYPTIC SPECIES: CONSIDERATIONS AND APPLICATIONS FOR ESTIMATING DETECTION, OCCUPANCY, AND ABUNDANCE OF SEMI-AQUATIC SNAKESOldham, Christian Robert 01 January 2016 (has links)
Snake species are notoriously difficult to study in the field due to their cryptic natural-histories and secretive behaviors. Difficulties associated with detection present challenges estimating parameters including occupancy and abundance, as well as responses to habitat degradation. Our objectives were to use Passive Integrated Transponder (PIT) telemetry to enhance detection of Queensnakes (Regina septemvittata) as compared to traditional capture-mark-recapture (CMR) survey techniques and to examine occupancy and abundance of Queensnakes and Northern Watersnakes (Nerodia sipedon) in streams of differing levels of anthropogenic impact within Central Kentucky. During 2013, we captured Queensnakes and implanted them with PIT tags. We detected significantly more tagged snakes using PIT telemetry than visual surveys. We did not observe significant differences in numbers of snakes detected using PIT telemetry at different times of day. We observed relatively high site fidelity of individuals. During 2014, we conducted point-count surveys of Northern Watersnakes and Queensnakes in streams characterized as highly degraded and lightly impaired. We estimated occupancy and conditional abundance among site types. We did not observe significant differences in occupancy or abundance between historically highly-impacted sites and less-impacted sites. We were able to determine significance of some environmental variables influencing detection of snakes.
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Efetividade da escada para peixes de uma barragem no rio Paraná para duas espécies migradoras neotropicais / Effectiveness of the fish ladder at a dam in the paraná river for two neotropical migratory speciesGutfreund, Carola 18 April 2017 (has links)
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Previous issue date: 2017-04-18 / Large hydroelectric dams along the Paraná River have caused severe impacts on fish communities as they represent obstacles to long-range migratory species that need to migrate to complete their life cycle. Dams can bring numerous problems through the interception of migratory routes and reduction of spawning areas. The most common measures used to mitigate the effect of these physical obstacles is the implementation of fish ladders. It is not only important to implement these structures, but also to monitor them.
This study was performed at the Engenheiro Sergio Motta Hydroelectric Power plant in the Upper Paraná River during December/2012 and March/2016. The aim of it was to evaluate the effectiveness of this structure in relation to the attractiveness rate and passage efficiency of to two Neotropical fish species in the fish ladder. In total, 563 fish of genus Leporinus (447 Leporinus obtusidens and 116 Leoporinus piavussu) were tagged and released with the implementation of 32-mm programmable transponders (PIT-tags). Radio Frequency Identification (RFID) was used to monitor the system. The attractiveness of the ladder was 8.7%. The minimum time to find it was 1.49 days for the fish released upstream and the maximum time was 449.86 days for the individuals released downstream. The release site had a significant influence on the entry rate of fish released on the other side of the river. No detection was observed for fish released downstream and upstream on the right bank of the river. Only the fish released on the same site where the fish ladder is located were detected, suggesting low attractiveness of the ladder in relation to the studied species. In the course of this study it was verified that for the two species studied it would be extremely important to increase the attractiveness at the entrance of the ladder, as well as to build a second ladder for fish on the right side of the river. / As grandes hidrelétricas ao longo do Rio Paraná têm causado impactos severos nas comunidades de peixes, pois representam obstáculos para as espécies migradoras de longa distância, que precisam migrar para completar seu ciclo de vida. As barragens podem trazer inúmeros problemas por meio da intercepção das rotas migratórias e redução das áreas de desova. As medidas mais comuns utilizadas para mitigar o efeito desses obstáculos físicos é a implementação de escadas para peixes. Não é somente importante a implementação dessas estruturas, como também o monitoramento. Esse estudo realizado na escada para peixes da Usina Hidrelétrica Engenheiro Sérgio Motta no alto Rio Paraná no período de dezembro/2012 a março/2016 teve como objetivo avaliar a efetividade dessa estrutura em relação a taxa de atratividade e eficiência de passagem para duas espécies de peixes migradores neotropicais. No total, foram marcados e liberados 563 peixes do gênero Leporinus (447 Leporinus obtusidens e 116 Leoporinus piavussu) com a implantação de transponders com códigos programáveis (PIT-tags) de 32 mm. Foi utilizado o sistema de rádio frequência (RFID Radio Frequency Identification) para o monitoramento do sistema. A atratividade da escada foi de 8,7%. O tempo mínimo para encontrar a escada correspondeu a 1,49 dias para os peixes liberados a montante e o tempo máximo foi de 449,86 dias para os indivíduos liberados a jusante. O local de liberação influenciou significativamente a taxa de entrada dos peixes liberados na margem oposta do rio, sendo que nenhuma detecção foi observada para peixes liberados na margem direita, tanto a jusante como a montante. Foram detectados apenas os peixes liberados na mesma margem onde a escada para peixes está localizada, sugerindo baixa atratividade da escada para as espécies analisadas. No decorrer deste estudo verificou-se que para as duas espécies estudadas seria extremamente importante aumentar a atratividade na entrada da escada, como também a construção de uma segunda escada para peixes no lado direito do rio.
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Aspectos de crescimento e mortalidade do guanhumi (CARDISOMA GUANHUMI) em um manguezal de acesso restrito na Ilha de Itamaracá – PECOSTA, Denise Fabiana de Moraes 19 August 2016 (has links)
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Previous issue date: 2016-08-19 / FACEPE / O conhecimento dos parâmetros de crescimento e mortalidade em braquiúros é fundamental para a
compreensão da sua dinâmica e para o manejo de suas populações. Neste sentido, foram estimados
os parâmetros de crescimento e mortalidade para Cardisoma guanhumi Latreille, 1825 (guaiamum),
uma espécie com elevada importância socioeconômica no nordeste brasileiro e atualmente
considerada pelo Ministério do Meio Ambiente como Criticamente em Perigo de extinção. As
amostragens foram efetuadas durante um ano, entre abril de 2015 a março de 2016, na margem
superior do mangue do CMA/ICMBio/CEPENE na ilha de Itamaracá, Pernambuco, Brasil. Foram
capturados, medidos e pesados 1078 indivíduos (572 machos e 506 fêmeas). Destes, 291 indivíduos
foram marcados com microchips PIT ("Passive Integrated Transponder"), para determinação dos
parâmetros de crescimento através dos incrementos de peso e tamanho e do crescimento individual.
Para a análise dos dados, foram utilizados o método ELEFAN I (baseado na distribuição de
frequência de largura de carapaça de 1078 indivíduos), inserido no pacote computacional Fisat II e
através da função GrowthTraject (baseada em incrementos individuais de 291 indivíduos marcados
com PITs, utilizando o pacote fishmethods (Ambiente de programação “R”). Os indivíduos de
C.guanhumi apresentaram largura da carapaça entre 20,9 e 70,0 mm (média: 43,45 mm, desvio
padrão: 8,53 mm, mediana: 44,05 mm) o peso total entre 4 e 162 g (média: 45,85 g, desvio padrão:
25,34 g, mediana: 44,0 g). Não houve diferenças significativas, em tamanho médio e peso médio,
entre machos e fêmeas. Os parâmetros de crescimento estimados com a função GrowthTraject para
130 incrementos (machos e fêmeas) foram: Linf (tamanho assintótico) = 108,03 mm (largura da
carapaça); K (coeficiente de crescimento) = 0,145 ano-1. A Mortalidade total (Z) da população,
estimada pelo método Length – converted Catch Curve (pacote FISAT II) usando os parâmetros de
crescimento do GrowthTraject foi de = 2,39 ano-1. Não ocorrem capturas comerciais nesta área
fechada, portanto, este valor equivale à mortalidade total e natural (Z=M). A idade dos indivíduos
capturados variou de 1,49 anos (20,9mm) a 7,02 anos (70,0mm). O recrutamento, calculado no
pacote FISAT II e estimado através da presença de juvenis, mostrou-se contínuo durante todo o
ano. Os métodos de análises de frequência e comprimento inseridos no pacote FISAT
(Bhattacharya, ELEFAN I e Shepherd’s) não foram capazes de determinar os parâmetros de
crescimento, provavelmente devido ao crescimento lento e recrutamento contínuo durante todo ano.
O tamanho total da população no manguezal do CMA foi estimado em 1262 indivíduos (+- 401ind.),
baseado nos dados de marcação e recaptura. / Knowledge on the growth parameters and mortality in brachyuran is fundamental to the
understanding of the dynamics and management of their populations. Growth and mortality
parameters were estimated for Cardisoma guanhumi Latreille, 1825 (locally known
as”guaiamum”), a species with high socio-economic importance in northeastern Brazil and
currently considered by the Ministry of the Environment as Critically Endangered of Extinction.
The samples were taken over one year, from April 2015 to March 2016, at the upper margin of a
small, isolated mangrove patch at CMA-ICMBio-CEPENE on Itamaracá Island, Pernambuco,
Brazil. A total of 1078 individuals (572 males and 506 females) were captured, measured and
weighed. Of these, 291 individuals were marked with PIT tags (Passive Integrated Transponder
tags), as to determine the growth parameters through the analysis of the increments in weight and
size and individual growth. For the data analysis, we used the ELEFAN I method (based on the
frequency distribution of carapace width 1078 individuals), inserted into the computer package
FISAT II and through the GrowthTraject function (based on individual increments of 291
individuals marked with PIT tags, using the fishmethods package ("R” Environment). C. guanhumi
showed carapace widths between 20.9 and 70.0 mm (mean: 43,45 mm, standard deviation: 8,53
mm, median: 44,05 mm) and total weight between 4 and 162 g (mean: 45,85 g, standard deviation:
25,34 g, median: 44,0 g). There were no significant differences in average size and average weight
between males and females. Growth parameters estimated with the fishmethods package, based on
130 increments (males and females), were: L∞ (asymptotic carapace width) = 108.03 mm; K
(coefficient growth) = 0.145 y-1. Total mortality (Z) of the population, estimated through the
Length-converted catch Curve method (FISAT II package), using the fishmethods growth
parameters, was 2.39 y-1. Since this is a restricted area without regular commercial catches, so this
value is roughly equivalent to the total and natural mortality (Z = M). The age of the individuals
captured ranged from 1.49 years (20,9 mm) to 7.02 years (70,0 mm). Recruitment, calculated in
FISAT II package and estimated by the presence of juveniles, showed to be continuous throughout
the year. The methods of length-frequency analysis inserted in the FISAT package (Bhattachary
of protective measures for this species.
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