scholarly journals Pairing long-term population monitoring and wildlife crossing structure interaction data to evaluate road mitigation effectiveness

2021 ◽  
Vol 257 ◽  
pp. 109085
Author(s):  
Greta M. Schmidt ◽  
Rebecca L. Lewison ◽  
Hilary M. Swarts
Keyword(s):  
Population Monitoring ◽  
Interaction Data ◽  
Structure Interaction ◽  
Road Mitigation

Using Long-Term Population Monitoring Data to Prioritize Conservation Action among Rare Plant Species

2019 ◽  
Vol 39 (2) ◽  
pp. 169 ◽  
Author(s):  
Holly L. Bernardo ◽  
Pati Vitt ◽  
Rachel Goad ◽  
Susanne Masi ◽  
Tiffany M. Knight
Keyword(s):  
Plant Species ◽  
Population Monitoring ◽  
Monitoring Data ◽  
Rare Plant ◽  
Conservation Action ◽  
Rare Plant Species

Do researchers impact their study populations? Assessing the effect of field procedures in a long term population monitoring of sea kraits

2012 ◽  
Vol 33 (3-4) ◽  
pp. 365-372 ◽  
Author(s):  
Thomas Fauvel ◽  
François Brischoux ◽  
Marine Jeanne Briand ◽  
Xavier Bonnet
Keyword(s):  
Body Condition ◽  
New Caledonia ◽  
Stress Hormones ◽  
Population Level ◽  
Population Monitoring ◽  
Long Term Effects ◽  
Negative Effects ◽  
Short Term ◽  
Head Morphology

Long term population monitoring is essential to ecological studies; however, field procedures may disturb individuals. Assessing this topic is important in worldwide declining taxa such as reptiles. Previous studies focussed on animal welfare issues and examined short-term effects (e.g. increase of stress hormones due to handling). Long-term effects with possible consequences at the population level remain poorly investigated. In the present study, we evaluated the effects of widely used field procedures (e.g. handling, marking, forced regurgitation) both on short-term (hormonal stress response) and on long-term (changes in body condition, survival) scales in two intensively monitored populations of sea kraits (Laticauda spp.) in New Caledonia. Focusing on the most intensively monitored sites, from 2002 to 2012, we gathered approximately 11 200 captures/recaptures on 4500 individuals. Each snake was individually marked (scale clipping + branding) and subjected to various measurements (e.g. body size, head morphology, palpation). In addition, a subsample of more than 500 snakes was forced to regurgitate their prey for dietary analyses. Handling caused a significant stress hormonal response, however we found no detrimental long-term effect on body condition. Forced regurgitation did not cause any significant effect on both body condition one year later and survival. These results suggest that the strong short-term stress provoked by field procedures did not translate into negative effects on the population. Although similar analyses are required to test the validity of our conclusions in other species, our results suggest distinguishing welfare and population issues to evaluate the potential impact of population surveys.

Paradoxical population resilience of a keystone predator to a toxic invasive species

2020 ◽  
Vol 47 (3) ◽  
pp. 260
Author(s):  
J. Sean Doody ◽  
David Rhind ◽  
Simon Clulow
Keyword(s):  
Population Level ◽  
Population Monitoring ◽  
Cane Toad ◽  
Keystone Predator ◽  
Individual Effects ◽  
Before And After ◽  
Animal Communities ◽  
Better Than ◽  
Population Resilience

Abstract ContextThe invasive cane toad (Rhinella marina) has decimated populations of a keystone predator, the yellow-spotted monitor (Varanus panoptes), causing trophic cascades in Australian animal communities. Paradoxically, some V. panoptes populations coexist with toads. Demonstrating patterns in heterogeneous population-level impacts could reveal mechanisms that mediate individual effects, and provide managers with the ability to predict future impacts and assist in population recovery. AimsThe aim of the present study was to search for spatial patterns of population resilience of V. panoptes to invasive cane toads. MethodsPublished literature, unpublished data, reports and anecdotal information from trained herpetologists were used to test the emerging hypothesis that resilient predator populations are mainly coastal, whereas non-resilient populations are mostly inland. Key resultsPost-toad invasion data from 23 V. panoptes populations supported the idea that toad impacts on V. panoptes were heterogeneous; roughly half the populations could be designated as resilient (n=13) and half as non-resilient (n=10). Resilient populations had longer times since toad invasion than did non-resilient populations (39 versus 9 years respectively), supporting the idea that some recovery can occur. Non-resilient populations were exclusively inland (n=10), whereas resilient populations were split between inland (n=5) and coastal (n=8) populations. Resilient inland populations, however, were mainly confined to areas in which decades had passed since toad invasion. ConclusionsThe findings suggest that coastal V. panoptes populations fare much better than inland populations when it comes to surviving invading cane toads. ImplicationsUnambiguous recovery of monitor populations remains undemonstrated and will require long-term population monitoring before and after toad invasion.

Intrafragment riverscape conservation for an imperiled, small-bodied, pelagic-broadcast spawning minnow: speckled chub (Macrhybopsis aestivalis)

2015 ◽  
Vol 72 (4) ◽  
pp. 527-537 ◽  
Author(s):  
Christopher W. Hoagstrom ◽  
Thomas P. Archdeacon ◽  
Stephen R. Davenport ◽  
David L. Propst ◽  
James E. Brooks
Keyword(s):  
Flow Regime ◽  
Monitoring Program ◽  
Population Monitoring ◽  
Older Individuals ◽  
High Quality ◽  
Broadcast Spawning ◽  
Distributional Patterns ◽  
Class Strength ◽  
Explained Variation

Intrafragment ecology is little studied for imperiled riverine fishes although river fragmentation and habitat loss increasingly threaten sensitive species. A long-term population-monitoring program in the Pecos River, New Mexico, provided detailed data for 15 annual cohorts of speckled chub (Macrhybopsis aestivalis), which were used to assess intrafragment patterns in recruitment and year-class strength in relation to distributional patterns, flow-regime characteristics, and air temperature. Cohorts avoided a degraded upstream reach. Age-1 and older individuals had distributions consistently centered within a central, relict-ecosystem reach that contained high-quality habitat. Age-0 individuals were widespread within the relict-ecosystem reach and a channelized reach downstream. Distributional patterns suggested that some individuals that recruited in the channelized reach dispersed upstream into relict-ecosystem habitat thereafter. One cohort always numerically dominated the population because cohorts never lived beyond 2 years. Recruitment was density-independent and predicted year-class strength. No aspect of the flow regime explained variation in recruitment. Year-class strength was consistent among cohorts because of density-dependent mortality. High-quality habitat in a centralized location, potential for dispersal between channelized and relict-ecosystem reaches, and diffuse distribution of pelagic-broadcast propagules throughout both reaches combined to facilitate successful annual recruitment and population persistence.

scholarly journals Environmental DNA facilitates accurate, indigenous-led, inexpensive, and multi-year population estimates of millions of Eulachon fish

2019 ◽  
Author(s):  
Meredith Pochardt ◽  
Jennifer M. Allen ◽  
Ted Hart ◽  
Sophie D. L. Miller ◽  
Douglas W. Yu ◽  
...  
Keyword(s):  
Area Under The Curve ◽  
Cost Savings ◽  
Environmental Dna ◽  
Population Monitoring ◽  
Population Estimates ◽  
Water Sampling ◽  
Mark Recapture ◽  
Temporal Sampling ◽  
The Relationship

AbstractAlthough environmental DNA shed from an organism is now widely used for species detection in a wide variety of contexts, mobilizing environmental DNA for management requires estimation of population size and trends rather than simply assessing presence or absence. However, the efficacy of environmental-DNA-based indices of abundance for long-term population monitoring have not yet been assessed. Here we report on the relationship between six years of mark-recapture population estimates for eulachon (Thaleichthys pacificus) and ‘eDNA rates,’ which are calculated from the product of stream flow and DNA concentration. Eulachon are a culturally and biologically important anadromous fish that have significantly declined in the southern part of their range but were historically rendered into oil and traded. Both the peak eDNA rate and the area under the curve of the daily eDNA rate were highly predictive of the mark-recapture population estimate, explaining 84.96% and 92.53% of the deviance respectively. Even in the absence of flow correction, the peak of the daily eDNA concentration explained an astonishing 89.53% while the area under the curve explained 90.74% of the deviance. These results support the use of eDNA to monitor eulachon population trends and represent a >80% cost savings over mark-recapture, which could be further increased with automated water sampling, reduced replication, and focused temporal sampling. Due to its logistical ease and affordability, eDNA sampling can facilitate monitoring a larger number of rivers and in remote locations where mark-recapture is infeasible.

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