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1.
Assessment and management of sea turtle populations is often limited by a lack of available data pertaining to at-sea distributions at appropriate spatial and temporal resolutions. Assessing the spatial and temporal distributions of marine turtles in an open system poses both observational and analytical challenges due to the turtles’ highly migratory nature. Surface counts of marine turtles in waters along the southern part of Florida’s east coast were made in and adjacent to the southeast portion of the Florida Current using standard aerial surveys during 2011 and 2012 to assess their seasonal presence. This area is of particular concern for sea turtles as interest increases in offshore energy developments, specifically harnessing the power of the Florida Current. While it is understood that marine turtles use these waters, here we evaluate seasonal variation in sea turtle abundance and density over two years. Density of sea turtles observed within the study area ranged from 0.003 turtles km-2 in the winter of 2011 to 0.064 turtles km-2 in the spring of 2012. This assessment of marine turtles in the waters off southeast Florida quantifies their in-water abundance across seasons in this area to establish baselines and inform future management strategies of these protected species. 相似文献
2.
James U. Van Dyke Luke M. McPhan Katie Howard Tracy Hamilton Liticia Ross Robyn J. Watts 《Austral ecology》2023,48(8):1681-1699
Freshwater turtles are important consumers in Australian freshwater ecosystems. They serve as scavengers, nutrient regulators, and as food sources and Totems for Traditional Owners throughout Australia. Despite their importance, most Australian freshwater turtle species are declining. The impact of winter wetland drying on turtle populations remains unknown, and winter exposure of hibernating turtles may be an important additional source of mortality. We aimed to examine turtle responses to seasonal and episodic wetland drying in wetlands using acoustic telemetry and active trapping. Wetlands were chosen that spanned a range of hydrological connectivity to the adjacent Edward/Kolety-Wakool River. We found that tagged Emydura macquarii typically exit wetlands disconnected from the adjacent permanent river prior to winter, and overwinter in the river. Female E. macquarii rapidly re-entered ‘home’ wetlands (wetlands in which they were initially tagged) the following spring, whereas males tended to leave the study area, returning occasionally. Although we were not able to evaluate a winter drying event, one of the wetlands experienced partial summer drying. All three local turtle species (E. macquarii, Chelodina expansa, C. longicollis) exited the wetland long before winter drying would have become a potential threat. Our results suggest that turtles in this system may be protected from winter wetland drying because they move to the adjacent permanent river prior to winter. Spending the winter in the river channel reduces the risks of being trapped in a drying wetland as temperatures drop in winter. 相似文献
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Shannon E. Pittman Timothy L. King Søren Faurby Michael E. Dorcas 《Conservation Genetics》2011,12(6):1589-1601
In this study, we sought to determine the population stability and genetic diversity of one isolated population of the federally-threatened
bog turtle (Glyptemys muhlenbergii) in North Carolina. Using capture–recapture data, we estimated adult survival and population growth rate from 1992 to 2007.
We found that the population decreased from an estimated 36 adult turtles in 1994 to approximately 11 adult turtles in 2007.
We found a constant adult survival of 0.893 (SE = 0.018, 95% confidence interval, 0.853–0.924) between 1992 and 2007. Using
18 microsatellite markers, we compared the genetic status of this population with five other bog turtle populations. The target
population displayed allelic richness (4.8 ± 0.5) and observed heterozygosity (0.619 ± 0.064) within the range of the other
bog turtle populations. Coalescent analysis of population growth rate, effective population size, and timing of population
structuring event also indicated the genetics of the target population were comparable to the other populations studied. Estimates
of effective population size were a proportion of the census size in all populations except the target population, in which
the effective population size was larger than the census size (30 turtles vs. 11 turtles). We attribute the high genetic diversity
in the target population to the presence of multiple generations of old turtles. This study illustrates that the demographic
status of populations of long-lived species may not be reflected genetically if a decline occurred recently. Consequently,
the genetic integrity of populations of long-lived animals experiencing rapid demographic bottlenecks may be preserved through
conservation efforts effective in addressing demographic problems. 相似文献
5.
Tiffany A. Bougie M. Zachariah Peery Carly N. Lapin James E. Woodford Jonathan N. Pauli 《The Journal of wildlife management》2022,86(5):e22234
Management generally targets the most tractable life stage to rescue declining populations; however, that stage may not have the largest influence on recovery. Freshwater turtles are declining globally and early stages are frequently targeted for management, although the effectiveness of these actions on population growth are relatively unknown because of incomplete demographic data. We estimated the hatchling yearly survival rate for a freshwater turtle in the field using in situ enclosures to collect missing demographic information. We used these data to develop demographic models to calculate growth rate for a hypothetical, declining population of wood turtles (Glyptemys insculpta) in Wisconsin, USA, 2014–2019. We modeled growth for populations across a range of scenarios from no management to combinations of nest protection and head-starting at varying levels of effort. Nest protection alone did not increase population growth rate, while head-starting alone increased population growth by 0.07, with the largest increase in growth rate, 0.11, resulting from combinations of both approaches. No combination of nest protection and head-starting, without an increase in adult survival rate from the observed 0.88 to ≥0.95, led to population stabilization or increase. Populations of freshwater turtles, like the wood turtle, will likely only recover with a multi-faceted approach that targets multiple life stages simultaneously. 相似文献
6.
Phosphorus (P) is one of main pollution elements of eutrophication. P emissions from different pathways and sources are a
key issue in the protection of water quality and sustainable watershed management practices. We have estimated net anthropogenic
P accumulation (NAPA), as an index of P pollution potential in the Beijing metropolitan region, China. The NAPA estimation
is based on an inventory of P fertilizer use, consumption of human food and animal feed, non-food P, and riverine P net flux.
The overall average NAPA for 1991, 1997, 2003, and 2007 are 777, 943, 1218, and 1084 kg P km−2 y−1, about two times that reported in developed countries. The Urban unit has the largest NAPA (5526 kg P km−2 y−1), whereas Mentougou P was negative, outputting 34 kg P km−2 y−1. P input of fertilizer is the largest source of NAPA, accounting for 40.7% (455 kg P km−2 y−1) of the total P input, followed by non-food P and P in human food and animal feed. NAPA is closely related to land use, on
average 5433 kg P km−2 y−1 in densely populated developed land, 503 kg P km−2 y−1 in agricultural land and 84 kg P km−2 y−1 in forest land. Human population density is the best single predictor of NAPA. Our results provide a basis for understanding
the potential impact of anthropogenic P inputs on environmental problems, such as nation-wide water quality degradation under
the current rapid urban expansion in modern China. 相似文献
7.
Alex C. Wieten Matthew J. Cooper Aaron D. Parker Donald G. Uzarski 《Wetlands Ecology and Management》2012,20(1):47-58
Great Lakes coastal wetlands are important habitats for turtles but few studies have looked at factors driving community structure
in these systems. We evaluated the effects of wetland type, vegetation, and abiotic conditions on turtle communities for 56
wetlands in Lakes Huron, Michigan, and Superior with data collected during the summers of 2000–2008. Overall, 1,366 turtles
representing seven species were captured using fyke nets. For the majority of species, catches were highest in drowned river
mouth wetlands In addition, turtles tended to be more abundant in water lilies, submersed aquatic vegetation, and cattails
compared to bulrush. We also found positive correlations between catches of four of the species as well as total turtle catch
and turtle species richness with a human disturbance gradient. These correlations suggest that turtles may be able to utilize
coastal wetland areas that are inhospitable to fish because of hypoxic conditions. Our results show the importance Great Lakes
coastal wetlands to turtles, and stress the need for managers to take into account turtle populations when preparing conservation
and restoration strategies. 相似文献
8.
Relative vulnerability of female turtles to road mortality 总被引:1,自引:0,他引:1
D. A. Steen M. J. Aresco S. G. Beilke B. W. Compton E. P. Condon C. Kenneth Dodd Jr. H. Forrester J. W. Gibbons J. L. Greene G. Johnson T. A. Langen M. J. Oldham D. N. Oxier R. A. Saumure F. W. Schueler J. M. Sleeman L. L. Smith J. K. Tucker & J. P. Gibbs 《Animal Conservation》2006,9(3):269-273
Recent studies suggest that freshwater turtle populations are becoming increasingly male-biased. A hypothesized cause is a greater vulnerability of female turtles to road mortality. We evaluated this hypothesis by comparing sex ratios from published and unpublished population surveys of turtles conducted on- versus off-roads. Among 38 166 turtles from 157 studies reporting sex ratios, we found a consistently larger female fraction in samples from on-roads (61%) than off-roads (41%). We conclude that female turtles are indeed more likely to cross roadways than are males, which may explain recently reported skewed sex ratios near roadways and signify eventual population declines as females are differentially eliminated. 相似文献
9.
Chaffin K Norton TM Gilardi K Poppenga R Jensen JB Moler P Cray C Dierenfeld ES Chen T Oliva M Origgi FC Gibbs S Mazzaro L Mazet J 《Journal of wildlife diseases》2008,44(3):670-686
The Alligator Snapping Turtle (Macrochelys temminckii) is a large freshwater turtle endemic to river systems that drain into the Gulf of Mexico. Turtle populations were sharply reduced by commercial harvest in the 1970s and 1980s; however, the species has yet to be protected under the Endangered Species Act. While anthropogenic stressors such as habitat fragmentation and degradation and illegal capture continue to threaten populations, the degree to which disease may be contributing to any decline of the Alligator Snapping Turtle is unknown. Data were collected from 97 free-ranging Alligator Snapping Turtles in nine waterways in Florida and Georgia from 2001 to 2006. Eleven turtles were captured more than once, resulting in a total sample pool of 123. Reference ranges were established for complete blood count, plasma biochemistry values, trace metals (mercury, zinc, copper, lead, and arsenic), and nutrient parameters (vitamins A, E, D, and selenium). Variations by capture location, sex, and season were detected and likely resulted from external factors such as habitat and diet. Turtles sampled in one location were positive for tortoise herpesviral antibodies. Blood mercury values also differed among populations. This study provides justification for the use of these long-lived aquatic turtles as biologic monitors of the health of local freshwater ecosystems. 相似文献
10.
Long-term studies were carried out in central Finland between 1985 and 2003 to examine the temporal and spatial variation
in the density of otter populations. Snow tracking was used to estimate the total population and the number of litters in
the study area. In total 52 otters, including 16 cubs in 11 litters, lived in the study area (1,650 km2) in 2002–2003. The otter population clearly increased during the study period. The increase in density of the otter population
was sigmoid, indicating that the population had reached the local carrying capacity. The density of the population was 0.12
individuals per river ha in 1985 and 0.29 individuals per river ha in 2002. The number of cubs per litter decreased when the
density of the population increased. Density-dependent offspring production, together with the auto-correlation function of
growth rate, indicates intraspecific competition in otter populations. Otters in a few river systems produced most of the
cubs, creating several small source populations in the entire study area. Otters in secondary (sink) habitats had a low reproduction
rate. Most otters lived in river systems with large lake surfaces. The number or area of lakes within the river system correlated
positively with the total number of otters, litters and cubs in the river system. The six river systems (out of 16) with the
largest water area of lakes produced 81.2% of all cubs born in the study area. However, the population growth rate per river
hectare or per river kilometre was equal in all kinds of river systems. Thus, among local otter populations in central Finland,
a source–sink system between different habitats seems to be prevalent. 相似文献
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Control of livestock diseases can become complicated when wild animals are involved. The Eurasian badger (Meles meles) is considered the principle wildlife host of Mycobacterium bovis (which causes bovine tuberculosis, bTB) in Great Britain and Ireland, but wild deer have also been implicated. Whether wild
deer are likely to perpetuate bTB in cattle depends on the exposure risks they pose, the mode of pathogen transmission, the
distances over which the disease can be transported and whether they can maintain infection within their own populations independently
of other sources. We evaluated the likely host status of each of four species of wild British deer (red, roe, fallow and Reeves'
muntjac) and the badger across a range of densities typically observed in Britain by manipulating the reproductive number
equation proposed by Anderson and May (1991). We estimate that roe deer almost certainly act as spillover hosts at densities lower than 30 km−2, red deer below 16 km−2, muntjac below 6 km−2, fallow below 4 km−2 and the badger below 2 km−2. We also estimate that muntjac will almost certainly act as maintenance hosts at densities above 56 km−2, fallow above 47 km−2 and badgers above 24 km−2. For densities between these values, we cannot be certain of the host status of these species, and for red and roe deer we
cannot be certain of host status under most natural conditions typically experienced in parts of Britain experiencing high
incidence of bTB in cattle. However, enhanced transmission rates resulting from artificially high densities such as might
be experienced at supplementary feeding sites may be sufficient to promote independent maintenance of infection. We were not
able to confidently assign host status to any species over a wide range of densities, but conclude that this is likely to
reflect reality, where host status may be affected as much by, for example, demographic fluctuations as it is by population
density. Our results imply densities below which populations of wild deer inhabiting cattle bTB hotspots ought to be maintained
in order to control the possibility of them perpetuating the cycle of intra- and interspecific M. bovis transmission. 相似文献
14.
Warren DE Jackson DC 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2008,178(2):133-148
Painted turtles can accumulate lactic acid to extremely high concentrations during long-term anoxic submergence, with plasma
lactate exceeding 200 mmol l−1. The aims of this review are twofold: (1) To summarize aspects of lactate metabolism in anoxic turtles that have not been
reviewed previously and (2) To identify gaps in our knowledge of turtle lactate metabolism by comparing it with lactate metabolism
during and after exercise in other vertebrates. The topics reviewed include analyses of lactate’s fate during recovery, the
effects of temperature on lactate accumulation and clearance, the interaction of activity and recovery metabolism, fuel utilization
during recovery, stress hormone responses during and following anoxia, and cellular lactate transport mechanisms. An analysis
of lactate metabolism in anoxic turtles in the context of the ‘lactate shuttle’ hypothesis is also presented. 相似文献
15.
Mark Hamann Chu The Cuong Nguyen Duy Hong Pham Thuoc Bui Thi Thuhien 《Biodiversity and Conservation》2006,15(11):3703-3720
To establish baseline data on the distribution, abundance and threats to marine turtles in Viet Nam we conducted surveys with
local fishers, community members and provincial Ministry of Fisheries staff from 17 of Viet Nam’s 29 coastal provinces. These
data indicate that five species of marine turtle reside in Viet Nam’s waters (loggerhead, olive ridley, leatherback, green
and hawksbill turtles), and four species nest on Viet Nam’s beaches (all of the above except the loggerhead turtle). It is
evident from these data that significant declines have occurred in both foraging and nesting populations of all five marine
turtle species found in Viet Nam. The greatest current threats to marine turtle populations in Viet Nam are habitat degradation,
the accidental and opportunistic of turtles capture by fishers and the direct take of nesting females and their eggs. Successful
conservation efforts have been made in recent years through collaboration between international Non Government Organisations
and several Vietnamese Government Ministries. Continued success of these projects and the development and implementation of
marine conservation policy will depend upon building awareness among Government employees, fishers and the general public
about marine turtle biology, ecology, and the need to protect them. 相似文献
16.
Influence of drainage divides versus arid corridors on genetic structure and demography of a widespread freshwater turtle,Emydura macquarii krefftii,from Australia
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The influence of Pleistocene climatic cycles on Southern Hemisphere biotas is not yet well understood. Australia's eastern coastal margin provides an ideal setting for examining the relative influence of landscape development, sea level fluctuation, and cyclic climatic aridity on the evolution of freshwater biodiversity. We examined the impact of climatic oscillations and physical biogeographic barriers on the evolutionary history of the wide‐ranging Krefft's river turtle (Emydura macquarii krefftii), using range‐wide sampling (649 individuals representing 18 locations across 11 drainages) and analysis of mitochondrial sequences (~1.3‐kb control region and ND4) and nuclear microsatellites (12 polymorphic loci). A range of phylogeographic (haplotype networks, molecular dating), demographic (neutrality tests, mismatch distributions), and population genetic analyses (pairwise FST, analysis of molecular variance, Bayesian clustering analysis) were implemented to differentiate between competing demographic (local persistence vs. range expansion) and biogeographic (arid corridor vs. drainage divide) scenarios. Genetic data reveal population genetic structure in Krefft's river turtles primarily reflects isolation across drainage divides. Striking north‐south regional divergence (2.2% ND4 p‐distance; c. 4.73 Ma, 95% higher posterior density (HPD) 2.08–8.16 Ma) was consistent with long‐term isolation across a major drainage divide, not an adjacent arid corridor. Ancient divergence among regional lineages implies persistence of northern Krefft's populations despite the recurrent phases of severe local aridity, but with very low contemporary genetic diversity. Stable demography and high levels of genetic diversity are inferred for southern populations, where aridity was less extreme. Range‐wide genetic structure in Krefft's river turtles reflects contemporary and historical drainage architecture, although regional differences in the extent of Plio–Pleistocene climatic aridity may be reflected in current levels of genetic diversity. 相似文献
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Unregulated commercial harvest remains a major threat for turtles across the globe. Due to continuing demand from Asian markets, a significant number of turtles are exported from the United States of America (US). Beginning in 2007, several southeastern states in the US implemented restrictions on the commercial harvest of turtles, in order to address the unsustainable take. We have summarized freshwater turtle exports from the US between 2002 and 2012 and demonstrated that the magnitude of turtle exports from the US remained high although the exports decreased throughout the decade. Louisiana and California were the major exporters. The majority of exports were captive bred, and from two genera, Pseudemys and Trachemys. We review the changes over the decade and speculate that the increase in export of wild turtles out of Louisiana after 2007 could be a consequence of strict regulations in surrounding states (e.g., Alabama, Florida). We suggest that if wild turtle protection is a goal for conservation efforts, then these states should work together to develop comprehensive regulation reforms pertaining to the harvest of wild turtles. 相似文献
19.
Potential impacts to freshwater ecosystems caused by flow regime alteration under changing climate conditions in Taiwan 总被引:3,自引:0,他引:3
Jian-Ping Suen 《Hydrobiologia》2010,639(1):115-128
Observed increases in the Earth’s surface temperature bring with them associated changes in precipitation and atmospheric
moisture that consequentially alter river flow regimes. Climate-induced flow regime changes are examined using the Indicators
of Hydrologic Alteration. This article uses observed daily streamflow data to examine the flow regime alteration and how these
changes might potentially affect freshwater ecosystems. Flow data from 23 gauging stations throughout Taiwan show that the
annual extreme water conditions (1-, 3-, 7-, 30-, 90-day annual minima or maxima) have increased alteration compared to baseline
periods (1961–1990). Specifically, more severe flood and drought events occur in the period after 1991 than the period from
1961 to 1990. The frequency and duration of flood and drought events also show increased fluctuation. Flow regimes are currently
being altered by stressors that will continue into the foreseeable future and it is also happing elsewhere in the world. Aquatic
organisms not only need to defend themselves from anthropogenic damage to the river system, but also face the on-going threat
from climate change-induced thermal and flow regime alteration. This article raises this issue so that water resources managers
may identify precautionary measures that reduce the cumulative effects of both anthropogenic flow alteration and changing
climate conditions. 相似文献
20.
The use of stable isotopes to investigate animal diets, habitat use, and trophic level requires understanding the rate at
which animals incorporate the 13C and 15N from their diets and the factors that determine the magnitude of the difference in isotopic composition between the animal’s
diet and that of its tissues. We determined the contribution of growth and catabolic turnover to the rate of 13C and 15N incorporation into several tissues that can be sampled non-invasively (skin, scute, whole blood, red blood cells, and plasma
solutes) in two age classes of a rapidly growing ectotherm (loggerhead turtles, Caretta caretta). We found significant differences in C and N incorporation rates and isotopic discrimination factors (Δ13C = δ13Ctissues − δ13Cdiet and Δ15N = δ15Ntissues − δ15Ndiet) among tissues and between age classes. Growth explained from 26 to 100% of the total rate of incorporation in hatchling
turtles and from 15 to 52% of the total rate of incorporation in juvenile turtles. Because growth contributed significantly
to the rate of isotopic incorporation, variation in rates among tissues was lower than reported in previous studies. The contribution
of growth can homogenize the rate of isotopic incorporation and limit the application of stable isotopes to identify dietary
changes at contrasting time scales and to determine the timing of diet shifts. The isotopic discrimination factor of nitrogen
ranged from −0.64 to 1.77‰ in the turtles’ tissues. These values are lower than the commonly assumed average 3.4‰ discrimination
factors reported for whole body and muscle isotopic analyses. The increasing reliance on non-invasive and non-destructive
sampling in animal isotopic ecology requires that we recognize and understand why different tissues differ in isotopic discrimination
factors. 相似文献