Spelling suggestions: "subject:"molecular escatologia""
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Molecular analysis of guano from bats in bat houses on organic pecan orchardsBrown, Veronica Angelelli 01 May 2010 (has links)
Bats are generalist predators of night flying insects, including many crop pests. Pecan nut casebearer (Acrobasis nuxvorella), hickory shuckworm (Cydia caryana), and several stink bug species are some of the most damaging crop pests in pecan orchards. Attracting bats to agricultural areas using bats houses may reduce the numbers of these pests and, consequently, their economic impact. This study uses quantitative polymerase chain reaction (QPCR) of mitochondrial DNA found in the guano of bats living in bat houses on organic pecan orchards to document the consumption of pecan nut casebearer, hickory shuckworm, and corn earworm (Helicoverpa zea), which is one of the most destructive pests of many crops throughout the world. This study also uses direct sequencing of insect remains in bat fecal pellets to identify species of stink bugs consumed by bats in bat houses. Evidence that bats prey upon crop pests supports the hypothesis that bats are both economically and ecologically beneficial to pecan farmers and provides incentives for bat conservation.
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Molecular analysis of guano from bats in bat houses on organic pecan orchardsBrown, Veronica Angelelli 01 May 2010 (has links)
Bats are generalist predators of night flying insects, including many crop pests. Pecan nut casebearer (Acrobasis nuxvorella), hickory shuckworm (Cydia caryana), and several stink bug species are some of the most damaging crop pests in pecan orchards. Attracting bats to agricultural areas using bats houses may reduce the numbers of these pests and, consequently, their economic impact. This study uses quantitative polymerase chain reaction (QPCR) of mitochondrial DNA found in the guano of bats living in bat houses on organic pecan orchards to document the consumption of pecan nut casebearer, hickory shuckworm, and corn earworm (Helicoverpa zea), which is one of the most destructive pests of many crops throughout the world. This study also uses direct sequencing of insect remains in bat fecal pellets to identify species of stink bugs consumed by bats in bat houses. Evidence that bats prey upon crop pests supports the hypothesis that bats are both economically and ecologically beneficial to pecan farmers and provides incentives for bat conservation.
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Noninvasive tracking of jaguars (Panthera onca) and co-occurring Neotropical felids in Belize, Central America by genotyping feces and remote camera trappingWultsch, Claudia 30 April 2013 (has links)
The elusive jaguar (Panthera onca) is extremely difficult to study due to its wide-ranging behavior, crepuscular activity peaks and its occurrence in low population densities in often dense forest habitats. Jaguars are also a species of concern, but our ability to provide for their survival is hampered by our inability to obtain reliable information on the status of their wild populations.
This study combines innovative noninvasive research techniques such as scat detector dogs and molecular scatology to conduct the first genetic study on wild populations of Neotropical felids coexisting across fragmented forest habitats in Belize, Central America. Specifically, we analyzed multi-locus data in jaguars (Panthera onca), pumas (Puma concolor) and ocelots (Leopardus pardalis) collected from 1053 scat samples across their range in the country. First, we optimized 14 polymorphic microsatellite loci for jaguars (Panthera onca), pumas (Puma concolor), and ocelots (Leopardus pardalis), and assessed their utility for cross-species amplification. Additionally, we tested their reliability for species and individual identification using fecal DNA as he primary DNA source. All microsatellite loci examined successfully cross-amplified in the three target species, and were polymorphic. Second, to maximize PCR amplification success and genotyping accuracy rates, and to minimize genotyping error rates for fecal DNA samples, we evaluated the performance of two fecal DNA storage techniques (dimethyl sulfoxide saline solution/DET buffer, 95% EtOH) suitable for long-term preservation at remote tropical sites. Additionally, we tested fecal DNA samples collected from four different scat locations (top, side, bottom, inside). DET buffer was the superior fecal DNA preservation method and collecting fecal DNA from side and top locations of the scat resulted in the highest PCR success rates.
For the main genetic study, we assessed the genetic conservation status of all three target species across the country of Belize. We examined levels of genetic diversity within different sites, (2) defined potential genetic clusters/populations, (3) and examined levels of gene flow and population structure for all three target species on a countrywide scale. Furthermore, we compared genetic diversity and gene flow levels among the three target species. Wild felids in Belize showed moderate levels of heterozygosity (HE = 0.60 - 0.70) with jaguars having the lowest genetic diversity with average expected heterozygosities of HE = 0.60 ± 0.05 and allelic richness (AR) of 4.94 ± 0.44 followed by pumas with HE = 0.65 ± 0.06 and AR of 7.52 ± 0.86 and ocelots with HE = 0.70 ± 0.05 and AR of 3.89 ± 0.23. We observed low to moderate levels of differentiation (FST = 0.00 - 0.15) and weak population structure using spatial Bayesian clustering techniques for all three target species. Although levels of genetic diversity and gene flow across the country are still fairly high, we did detect evidence of fragmentation indicating the risk of further habitat loss and fragmentation for wild felids.
Felids were simultaneously monitored across all study sites by remote sensing camera traps, which allows for a comparison of density estimates obtained from two different noninvasive survey approaches. Furthermore, analytical methods for density estimation are advancing rapidly, making it difficult to choose the optimal technique. Thus, we compared a variety of density estimators including the conventional approach of estimating abundance ( ) in programs CAPTURE and MARK and dividing abundance by the effective trapping area (ETA), the recently developed spatially explicit capture-recapture (SECR) models, both the likelihood-based approach (ML-SECR) in program DENSITY and the Bayesian approach (B-SECR) in program SPACECAP, and finally the genetic-based mark-recapture one sampling occasion estimator in program CAPWIRE. Although different survey methods using various density estimators produced similar density estimates, confidence levels and coefficients of variation varied, with SECR methods resulting in the least precise estimates. Detection probabilities were generally higher for noninvasive genetic sampling than for camera trapping. Both techniques were shown to be reliable and highly efficient survey methods for density estimation of low-density Neotropical felids living in challenging environments such as the tropics. While less precise, SECR CMR models are probably a more realistic reflection of our uncertainty. They hold great promise for density estimation studies for wide-ranging and territorial carnivore species, especially if precision can be improved through study design or analysis advancements in the future.
In conclusion, our results demonstrated that noninvasive sampling techniques such as molecular scatology and remote camera trapping are efficient research approaches to study multiple Neotropical felids in a multifaceted way and on a countrywide scale. We believe that the techniques and analyses developed in this study are widely applicable and relevant to the conservation and management of other elusive and difficult to study wild felids worldwide. / Ph. D.
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Pine marten diet and habitat use within a managed coniferous forestCaryl, Fiona Mae January 2008 (has links)
Increased afforestation and protective legislation in the latter half of the 20th Century allowed the British pine marten Martes martes population to recover from near extinction. Although still largely confined to northern Scotland, the marten population is expanding its size and range by utlising coniferous plantation forests which have become increasingly available. However, little is known about the marten’s ecology in plantation forestry, and less about how they may adapt to changing silvicultural trends. This study investigated aspects of pine marten ecology within Morangie forest, a managed plantation in NE Scotland, with the ultimate aim of formulating management guidelines for modern plantation forests. During the course of the study 11 pine marten were radiotracked and their home ranges mapped to examine marten-habitat associations at several spatial scales. Compositional analysis of habitat based on dominant vegetation type showed that martens established their home ranges in areas dominated by mature forest, whilst showing relative avoidance for open heath moor and grazed pasture. Within home ranges, foraging martens utilised patches of graminoid vegetation, such as those typically associated with Microtus voles, in areas with little or no tree canopy cover. These findings provide unequivocal evidence that fine-scale patches of non-forested habitat provide crucial foraging resources for marten, and therefore ought to be provisioned for in forest management plans. To assist the implementation of these requirements in forest planning, a model was developed to predict the fine scale distribution of Microtus-rich foraging habitat for marten using GIS-based habitat variables that are routinely available to forest managers: topographic wetness index, stand tree height and stand basal area. Management recommendations of ways to improve wind-firm plantation forests as habitats for pine marten are provided. To augment the investigation of marten spatial ecology, the diet of martens was examined seasonally through the analysis of contents from c. 2450 scats, 86 % of which were genetically identified as being pine marten in origin. Marten diets displayed marked seasonality, but small mammals, berries and small birds were the principal foods consumed based on both frequency of occurrence and estimated weight of biomass ingested. Comparison of the relative composition of small mammal species in the diet with those available in the environment revealed that marten displayed an indisputable preference for Microtus voles. Such habits demonstrate that the niche of Scottish martens has diverged from those in mainland populations which predominantly prey upon Clethrionomys voles. A comparison of the marten’s winter diet with those found in studies at similar latitudes (58°N) demonstrated that the Scottish diet was more similar to diets at more southerly latitudes as they contained more fruit and fewer large mammals than typically boreal diets. Investigation of inter-annual variation of the marten’s spring diet from five successive years revealed that Microtus were consistently the most important prey species in the diet each year. Indirect evidence of the relative abundance of Microtus suggested that Microtus populations were non-cyclic. Findings are discussed with reference to the unique ecological circumstances confronting marten in the Scotland; typical of insular populations the UK has a depauperate native fauna in comparison with mainland Europe, in addition to this, mild climatic conditions, particularly over winter, and a historically fragmented landscape appear to have allowed the niche of the Scottish marten to diverge from that considered typical elsewhere in its range. The Scottish marten is dependent on both forested and open habitats, and is both a Microtus specialist and trophic generalist.
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