scholarly journals Subterranean movement inferred by temporary emigration in Barton Springs salamanders (Eurycea sosorum)

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11246
Author(s):  
Nathan F. Bendik ◽  
Dee Ann Chamberlain ◽  
Thomas J. Devitt ◽  
Sarah E. Donelson ◽  
Bradley Nissen ◽  
...  
Keyword(s):  
Body Size ◽  
Habitat Management ◽  
Conservation Strategy ◽  
Movement Behavior ◽  
Temporary Emigration ◽  
Surface Population ◽  
Capture Recapture ◽  
Sampling Intervals ◽  
Barton Springs ◽  
Subterranean Habitat

Movement behavior is an important aspect of animal ecology but is challenging to study in species that are unobservable for some portion of their lives, such as those inhabiting subterranean environments. Using four years of robust-design capture-recapture data, we examined the probability of movement into subterranean habitat by a population of endangered Barton Springs salamanders (Eurycea sosorum), a species that inhabits both surface and subterranean groundwater habitats. We tested the effects of environmental variables and body size on survival and temporary emigration, using the latter as a measure of subterranean habitat use. Based on 2,046 observations of 1,578 individuals, we found that temporary emigration was higher for larger salamanders, 79% of which temporarily emigrated into subterranean habitat between primary sampling intervals, on average. Body size was a better predictor of temporary emigration and survival compared to environmental covariates, although coefficients from lower ranked models suggested turbidity and dissolved oxygen may influence salamander movement between the surface and subsurface. Surface population dynamics are partly driven by movement below ground and therefore surface abundance estimates represent a fraction of the superpopulation. As such, while surface habitat management remains an important conservation strategy for this species, periodic declines in apparent surface abundance do not necessarily indicate declines of the superpopulation associated with the spring habitat.

scholarly journals ESTIMATING SURVIVAL AND TEMPORARY EMIGRATION IN THE MULTISTATE CAPTURE–RECAPTURE FRAMEWORK

Ecology ◽  
2004 ◽  
Vol 85 (8) ◽  
pp. 2107-2113 ◽  
Author(s):  
Michael Schaub ◽  
Olivier Gimenez ◽  
Benedikt R. Schmidt ◽  
Roger Pradel
Keyword(s):  
Temporary Emigration ◽  
Capture Recapture

scholarly journals Expert knowledge assessment of threats and conservation strategies for breeding Hen Harrier and Short-eared Owl across Europe

2020 ◽  
pp. 1-18
Author(s):  
DARÍO FERNÁNDEZ-BELLON ◽  
JOHN LUSBY ◽  
JULES BOS ◽  
TONIO SCHAUB ◽  
ALAN MCCARTHY ◽  
...  
Keyword(s):  
Protected Areas ◽  
Habitat Management ◽  
Expert Knowledge ◽  
Prey Availability ◽  
Active Management ◽  
Conservation Strategy ◽  
Conservation Strategies ◽  
Conservation Threats ◽  
The Impact ◽  
Hen Harrier

Summary Hen Harrier Circus cyaneus and Short-eared Owl Asio flammeus are open-country birds of prey with overlapping distributions. Although both species face similar conservation threats across their ranges, work to date has largely been undertaken at a national scale with few attempts to collate and assess factors relevant to their conservation at an international scale. Here we use an expert knowledge approach to evaluate the impact of conservation threats and the effectiveness of conservation strategies for each species across Europe. We report results of responses to a questionnaire from 23 Hen Harrier experts from nine countries and 12 Short-eared Owl experts from six countries. The majority of responses for both species reported declines in breeding numbers. The perceived impact of threats was broadly similar for both species: ecological factors (predation, extreme weather and prey availability), changes in land use (habitat loss and agricultural intensification) and indirect persecution (accidental nest destruction) were considered to be the greatest threats to breeding Hen Harrier and Short-eared Owl. Short-eared Owl experts also highlighted lack of knowledge and difficulties associated with monitoring as a major conservation challenge. Despite broad-scale similarities, geographical variation was also apparent in the perceived importance of conservation threats, with some threats (such as direct persecution, large-scale afforestation or habitat degradation) requiring country-specific actions. Implementation of different conservation strategies also varied between countries, with the designation of protected areas reported as the most widespread conservation strategy adopted, followed by species and habitat management. However, protected areas (including species-specific protected areas) were perceived to be less effective than active management of species and habitats. These findings highlight the overlap between the conservation requirements of these two species, and the need for collaborative international research and conservation approaches that prioritise pro-active conservation strategies subject to continued assessment and with specific conservation goals.

scholarly journals Abundance, survival and temporary emigration of bottlenose dolphins (Tursiops sp.) off Useless Loop in the western gulf of Shark Bay, Western Australia

2012 ◽  
Vol 63 (11) ◽  
pp. 1059 ◽  
Author(s):  
Krista Nicholson ◽  
Lars Bejder ◽  
Simon J. Allen ◽  
Michael Krützen ◽  
Kenneth H. Pollock
Keyword(s):  
Western Australia ◽  
Bottlenose Dolphins ◽  
Early Spring ◽  
Anthropogenic Activity ◽  
Apparent Survival ◽  
Photo Identification ◽  
Temporary Emigration ◽  
Shark Bay ◽  
Abundance Estimates ◽  
Capture Recapture

Capture–recapture models were used to provide estimates of abundance, apparent survival and temporary emigration of Indo-Pacific bottlenose dolphins (Tursiops sp.) in a 226-km2 study area off Useless Loop in the western gulf of Shark Bay, Western Australia. Photo-identification data were collected during boat-based surveys in Austral autumn to early spring (April–September) from 2007 to 2011. Abundance estimates varied from 115 (s.e. 5.2, 95% CI 105–126) individuals in 2008 to 208 (s.e. 17.3, 95% CI 177–245) individuals in 2010. The variability in abundance estimates is likely to be a reflection of how individuals used the study area, rather than fluctuations in true population size. The best fitting capture–recapture model suggested a random temporary emigration pattern and, when coupled with relatively high temporary emigration rates (0.33 (s.e. 0.07) – 0.66 (s.e. 0.05)) indicated that the study area did not cover the entire ranges of the photo-identified dolphins. Apparent survival rate is a product of true survival and permanent emigration and was estimated annually at 0.95 (s.e. 0.02). Since permanent emigration from the study area is unlikely, true survival was estimated to be close to 0.95. This study provides a robust baseline for future comparisons of dolphin demographics, which may be of importance should climate change or increasing anthropogenic activity affect this population.

scholarly journals A Robust Design Capture-Recapture Analysis of Abundance, Survival and Temporary Emigration of Three Odontocete Species in the Gulf of Corinth, Greece

PLoS ONE ◽  
2016 ◽  
Vol 11 (12) ◽  
pp. e0166650 ◽  
Author(s):  
Nina Luisa Santostasi ◽  
Silvia Bonizzoni ◽  
Giovanni Bearzi ◽  
Lavinia Eddy ◽  
Olivier Gimenez
Keyword(s):  
Robust Design ◽  
Temporary Emigration ◽  
Gulf Of Corinth ◽  
Capture Recapture ◽  
Design Capture

Informing compensatory habitat creation with experimental trials: a 3-year study of a threatened amphibian

Oryx ◽  
2017 ◽  
Vol 53 (2) ◽  
pp. 310-320 ◽  
Author(s):  
Jose W. Valdez ◽  
Kaya Klop-Toker ◽  
Michelle P. Stockwell ◽  
Loren Fardell ◽  
Simon Clulow ◽  
...  
Keyword(s):  
Habitat Management ◽  
Large Scale ◽  
Mitigation Strategies ◽  
Conservation Strategy ◽  
Limiting Factors ◽  
Turnover Rates ◽  
High Turnover ◽  
Habitat Creation ◽  
Experimental Trials ◽  
Compensatory Habitat

AbstractThe creation or restoration of habitat to mitigate biodiversity loss is a common conservation strategy. Evidence-based research via an extensively monitored trial study should be undertaken prior to large-scale implementation to predict success and identify potential limiting factors. We constructed an experimental trial habitat for the threatened green and golden bell frog Litoria aurea, in Australia, to inform a broader programme of compensatory habitat creation. Individuals were released into the trial plot and a nearby natural wetland for comparison to determine if the created habitat would support their growth, survival and persistence. Half of the trial waterbodies were enclosed within an exclusion fence to separate the effects of habitat suitability from ecological processes. We found the habitat provided L. aurea with sufficient resources to grow, survive and persist for 3 years. However, no breeding occurred, and further investigations need to focus on understanding the drivers of reproduction. Although a disease outbreak occurred during the study, persistence continued for the next 2 years. This was attributed to the large number of individuals released, a strategy we recommend for future mitigation strategies to account for low survival and high turnover rates. Dispersal probably affected abundance in the unfenced areas, and landscape-level initiatives are suggested for this species. This study demonstrates that experimental trials are valuable, as they can inform future habitat management by identifying limitations that could hinder success prior to the implementation of large-scale initiatives.

scholarly journals Which Pitfall Traps and Sampling Effort to Choose to Evaluate Cropping System Effects on Spider and Carabid Assemblages?

2020 ◽  
Author(s):  
Antoine Gardarin ◽  
Muriel Valantin-Morison
Keyword(s):  
Body Size ◽  
Habitat Management ◽  
Cropping Systems ◽  
Cropping System ◽  
Pitfall Trap ◽  
Sampling Effort ◽  
Pitfall Traps ◽  
Arthropod Communities ◽  
Trap Design ◽  
Activity Density

Abstract In arable agroecosystems, arthropod communities often have a reduced abundance and diversity, which represents a challenge for sampling techniques needed to detect small differences among these simplified communities. We evaluated the suitability of pitfall traps for comparing the effects of cropping systems on arthropod communities. In a field experiment, we compared the effects of two pitfall trap diameters, the type of preserving fluid and the sampling effort on three metrics (activity density, taxonomic richness, and community weighted mean [CWM] of body size) for carabids and spiders. Trap size affected the observed composition of communities, with large traps yielding a higher proportion of spiders, and a higher richness and CWM body size for both taxa. The type of preserving fluid had a weaker effect. Simulations with various sampling efforts showed that only very different communities could be distinguished with less than 10 traps per field or less than 30 field replicates. Fewer traps were required to find differences between cropping systems for body size than for other metrics. Carabid activity density and body size, and spider genus richness, were the variables better distinguishing between cropping systems with the smallest sampling effort. A high sampling effort was required for comparing activity density and richness across cropping systems. Selection of the most appropriate trap design, metrics, and crops are the main factors for optimizing the trade-off between sampling effort and the ability to detect arthropod community responses to habitat management.

Adult survival and temporary emigration in the common toad

2004 ◽  
Vol 82 (6) ◽  
pp. 859-872 ◽  
Author(s):  
Thierry Frétey ◽  
Emmanuelle Cam ◽  
Bernard Le Garff ◽  
Jean-Yves Monnat
Keyword(s):  
Bufo Bufo ◽  
Adult Survival ◽  
First Order ◽  
Temporary Emigration ◽  
Lek Mating ◽  
Capture Recapture ◽  
The Common ◽  
Intermittent Breeding ◽  
Using Data ◽  
The Individual

In vertebrates exhibiting intermittent breeding, breeding activity is a factor of critical importance in capture–recapture studies using data from individually marked animals. Nonbreeders can be absent from locations used by breeders and can be considered "temporary emigrants". We addressed the influence of sex on survival in common toads, Bufo bufo (L., 1758), using the Joly–Seber model and the existance of temporary emigration in male common toads by assessing trap-dependence and by conducting a robust design analysis. We addressed the hypothesis that the probability of the presence of an individual in the study area depends on the presence of the individual the year before (i.e., that transitions between reproductive states are a first-order Markovian process). Results provided support for the hypotheses of random temporary emigration, of sex-specific differences in survival, and of the presence of "transients" in males. Females had intermediate survival compared with the groups of "transients + residents" and "resident" males. Females had lower recapture probability under the Joly–Seber model, which may be interpreted as evidence of lower breeding probability or lower detectability of breeding females. Behaviour may explain this difference in that females may attend ponds for shorter periods. This may be common in species where females aggregate to seek fertilization and lay eggs in locations attended by males and in species with a "resource-based lek" mating system.

On the reliability of enumeration for mark and recapture census of voles

1976 ◽  
Vol 54 (6) ◽  
pp. 1019-1024 ◽  
Author(s):  
Ray Hilborn ◽  
James A. Redfield ◽  
Charles J. Krebs
Keyword(s):  
Computer Simulation ◽  
Population Size ◽  
Individual Variation ◽  
Population Parameters ◽  
Small Rodents ◽  
Capture Recapture ◽  
Sampling Intervals ◽  
Average Individual ◽  
Probability Of Capture

Some studies of populations in small rodents rely on enumeration of individuals to provide an estimate of population size. A computer simulation of the capture–recapture process was used to examine the influence of five population parameters on the reliability of enumeration. Enumeration is shown to be insensitive to population size, survival between sampling intervals, and individual variation in the probability of capture. Enumeration is sensitive to the probability of capture; if the probability of capture for the average individual falls below 0.5, the enumeration technique provides a poor estimate of population size. Enumeration is also extremely sensitive to reduced probabilities of capture for unmarked animals. Data from capture–recapture studies of five species of Microtus were used in the computer simulation, and it was concluded for these five species that enumerated populations are at least 10–20% smaller than the actual populations.

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