Reducing the primary exposure risk of Henderson crakes (Zapornia atra) during aerial broadcast eradication by selecting appropriate bait colour

2016 ◽  
Vol 43 (4) ◽  
pp. 298 ◽  
Author(s):  
Steffen Oppel ◽  
Jennifer L. Lavers ◽  
Alexander L. Bond ◽  
Gavin Harrison
Keyword(s):  
Mixed Models ◽  
Native Species ◽  
Exposure Risk ◽  
Island Endemic ◽  
Invasive Predators ◽  
Species Of Conservation Concern ◽  
In Captivity ◽  
Specific Variation ◽  
Conservation Concern ◽  
Native Invasive

Context Operations to eradicate non-native invasive predators from islands frequently put native species at risk of consuming harmful substances, such as poison bait. The incorporation of certain colours in poison-bait pellets may reduce the risk of bait consumption and, therefore, non-target mortality. Previous work indicated that birds generally avoid blue or green colours; however, there is substantial inter-specific variation in this preference, and more experimental work on species of conservation concern is needed. Aims We tested whether a globally threatened island endemic, the Henderson crake (Zapornia atra), which suffered substantial mortality during a rat-eradication attempt on Henderson Island in 2011, would consume fewer blue than green pellets, which were used during the previous eradication attempt. Methods We held 22 Henderson crakes in captivity and provided them with either blue or green non-toxic pellets for 5 days in June and July 2015. We measured consumption and used linear mixed models to evaluate whether bait colour influenced consumption. Key results Henderson crakes did not consume any dry pellets, and all trials were conducted with wet bait pellets. We found slightly lower consumption of blue pellets than green pellets, and substantial variation among individuals. Females (n = 17) consumed 24% less blue than green bait, whereas males (n = 5) consumed 77% less blue than green bait. Conclusion Henderson crakes are unlikely to consume dry pellets, and will likely consume fewer blue than green bait pellets. Implications We recommend that any future rat eradication on Henderson Island considers using blue rather than green baits and targets dry weather to reduce the risk of Henderson crakes consuming toxic rodenticide bait pellets.

scholarly journals Intrinsic Prey Preference and Selection of the Giant Gartersnake: A Threatened Predator in a Nonnative Prey-Dominated Community

2020 ◽  
Vol 11 (1) ◽  
pp. 164-173
Author(s):  
Julia S.M. Ersan ◽  
Brian J. Halstead ◽  
Erica L. Wildy ◽  
Michael L. Casazza ◽  
Glenn D. Wylie
Keyword(s):  
Exotic Species ◽  
Native Species ◽  
Prey Selection ◽  
Central Valley ◽  
Prey Preference ◽  
Live Prey ◽  
Species Of Conservation Concern ◽  
Conservation Concern ◽  
Behavioral Trials ◽  
Selection Of

Abstract The introduction of exotic species into an environment can introduce great change in the trophic dynamics of native species. This is of even greater concern if the native species is of conservation concern. The giant gartersnake, Thamnophis gigas, an endemic predator of the Central Valley of California and a species of conservation concern at the state and federal levels, has declined as a result of conversion of its once vast wetland habitat to agriculture. Another anthropogenic factor contributing to this snake's changing ecology is the introduction of nonnative prey into the species' habitats. These introductions have resulted in a prey community that is almost completely composed of exotic species and have potential for considerable effects. In order to assess prey preference and selection we performed three sets of behavioral trials on naïve neonates. We examined 1) neonate prey preference in response to olfactory cues of prepared prey extracts, 2) neonate consumption of different live prey items presented simultaneously; and 3) terrestrial feeding behavior and/or latency to successful attack. Results from the olfactory study suggest that native Sierran treefrogs, Pseudacris sierra, are preferred by neonates. Results from consumption trials suggest that neonates are more likely to select frog species than fish species. This is the first study that we are aware of that examines prey selection of this threatened species and serves to inform its conservation and management.

scholarly journals Loss of Predator Discrimination by Critically Endangered Vancouver Island Marmots Within Five Generations of Breeding for Release

2021 ◽  
Vol 2 ◽  
Author(s):  
Graham P. Dixon-MacCallum ◽  
Johnathan L. Rich ◽  
Natasha Lloyd ◽  
Daniel T. Blumstein ◽  
Axel Moehrenschlager
Keyword(s):  
Vancouver Island ◽  
Predator Recognition ◽  
Critically Endangered ◽  
Species Of Conservation Concern ◽  
Mammalian Predators ◽  
In Captivity ◽  
Two Generations ◽  
In The Wild ◽  
Conservation Concern ◽  
Changes Over Time

Conservation translocations, which involve the intentional movement and release of organisms for conservation benefit, are increasingly required to recover species of conservation concern. In order to maximize post-release survival, and to accomplish conservation translocation objectives, animals must exhibit behaviors that facilitate survival in the wild. The Vancouver Island marmot (Marmota vancouverensis) is a critically endangered endemic in Canada which has been captive-bred for 24 years for reintroductions and reinforcements that have increased the wild population from ~30 to more than 200 individuals. Despite this success many marmots are killed by predators after release and predation represents a major hurdle to full marmot recovery. To better understand if captive-bred marmots are prepared for the novel environment into which they will be released, and to determine whether such suitability changes over time, we presented taxidermy mounts of mammalian predators and non-predators to marmots that were wild-caught, and captive born for between one and five generations. We also examined mortality of offspring from marmots we tested that had been released to the wild. A minimum of 43% of offspring were killed by predators in the wild over 17 years, most by cougars. Marmots in captivity generally responded to taxidermy mounts by decreasing foraging and increasing vigilance, and overall responded more strongly to predators than non-predators, especially wolves. However, marmots in captivity for more than two generations lacked discrimination between cougars, non-predators, and controls, suggesting a rapid loss of predator recognition. This study was only possible because predator-recognition trials were initiated early in the conservation translocation program, and could then be repeated after a number of generations. The finding that changes occurred relatively rapidly (within five generations during which changes in genetic diversity were negligible) suggests that behavioral suitability may deteriorate more rapidly than genetics would suggest. Strategies addressing potential behavior loss should be considered, including sourcing additional wild individuals or pre-release training of captive-born individuals. Subsequently, post-release survival should be monitored to determine the efficacy of behavior-optimization strategies.

Seasonal variation in plasma corticosterone concentrations in wild and captive adult Duvaucel's geckos (Hoplodactylus duvaucelii) in New Zealand

2010 ◽  
Vol 58 (4) ◽  
pp. 234 ◽  
Author(s):  
Manuela Barry ◽  
John F. Cockrem ◽  
Dianne H. Brunton
Keyword(s):  
Seasonal Variation ◽  
New Zealand ◽  
Body Temperature ◽  
Body Condition ◽  
Plasma Corticosterone ◽  
Reproductive Condition ◽  
Species Of Conservation Concern ◽  
Significant Seasonal Variation ◽  
In Captivity ◽  
Conservation Concern

Most of New Zealand’s herpetofauna species are threatened and in decline. Yet, little is known about their basic physiology and endocrinology. This study examined plasma corticosterone (CORT) concentrations in a threatened endemic New Zealand reptile, the Duvaucel’s gecko, in relation to season, sex, body temperature, body condition and female reproductive condition (pregnant versus non-pregnant). In addition, seasonal plasma CORT concentrations were compared between captive geckos from a breeding facility and a wild population to determine whether concentrations of CORT were chronically elevated in captive lizards. Plasma CORT concentrations showed significant seasonal variation, but were not related to sex, body temperature, body condition or female reproductive condition. Geckos, which successfully bred in captivity each year, did not exhibit chronically elevated plasma CORT levels but showed an elevation of plasma CORT concentrations in summer compared with wild geckos. Information on basal CORT concentrations in species of conservation concern can be beneficial for improving their management and can aid in identifying and evaluating stress-related changes in hormone patterns of individuals and chronic stress, which is particularly relevant for threatened species breeding programs.

Mutual dilution of infection by an introduced parasite in native and invasive stream fishes across Hawaii

Parasitology ◽  
2016 ◽  
Vol 143 (12) ◽  
pp. 1605-1614 ◽  
Author(s):  
RODERICK B. GAGNE ◽  
DAVID C. HEINS ◽  
PETER B. MCINTYRE ◽  
JAMES F. GILLIAM ◽  
MICHAEL J. BLUM
Keyword(s):  
Water Quality ◽  
Native Species ◽  
Host Density ◽  
Dilution Effect ◽  
Urban Land Use ◽  
Parasite Abundance ◽  
Species Of Conservation Concern ◽  
Awaous Stamineus ◽  
Conservation Concern ◽  
Camallanus Cotti

SUMMARYThe presence of introduced hosts can increase or decrease infections of co-introduced parasites in native species of conservation concern. In this study, we compared parasite abundance, intensity, and prevalence between nativeAwaous stamineusand introduced poeciliid fishes by a co-introduced nematode parasite (Camallanus cotti) in 42 watersheds across the Hawaiian Islands. We found that parasite abundance, intensity and prevalence were greater in native than introduced hosts. Parasite abundance, intensity and prevalence withinA. stamineusvaried between years, which largely reflected a transient spike in infection in three remote watersheds on Molokai. At each site we measured host factors (length, density of native host, density of introduced host) and environmental factors (per cent agricultural and urban land use, water chemistry, watershed area and precipitation) hypothesized to influenceC. cottiabundance, intensity and prevalence. Factors associated with parasitism differed between native and introduced hosts. Notably, parasitism of native hosts was higher in streams with lower water quality, whereas parasitism of introduced hosts was lower in streams with lower water quality. We also found that parasite burdens were lower in both native and introduced hosts when coincident. Evidence of a mutual dilution effect indicates that introduced hosts can ameliorate parasitism of native fishes by co-introduced parasites, which raises questions about the value of remediation actions, such as the removal of introduced hosts, in stemming the rise of infectious disease in species of conservation concern.

scholarly journals Experimental removal of introduced slider turtles offers new insight into competition with a native, threatened turtle

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7444 ◽  
Author(s):  
Max R. Lambert ◽  
Jennifer M. McKenzie ◽  
Robyn M. Screen ◽  
Adam G. Clause ◽  
Benjamin B. Johnson ◽  
...  
Keyword(s):  
Native Species ◽  
Field Experiments ◽  
Slider Turtle ◽  
Species Of Conservation Concern ◽  
Ecological Resources ◽  
Mesocosm Experiments ◽  
In The Wild ◽  
Western Pond Turtle ◽  
Negative Impacts ◽  
Conservation Concern

The red-eared slider turtle (Trachemys scripta elegans; RES) is often considered one of the world’s most invasive species. Results from laboratory and mesocosm experiments suggest that introduced RES outcompete native turtles for key ecological resources, but such experiments can overestimate the strength of competition. We report on the first field experiment with a wild turtle community, involving introduced RES and a declining native species of conservation concern, the western pond turtle (Emys marmorata; WPT). Using a before/after experimental design, we show that after removing most of an introduced RES population, the remaining RES dramatically shifted their spatial basking distribution in a manner consistent with strong intraspecific competition. WPT also altered their spatial basking distribution after the RES removal, but in ways inconsistent with strong interspecific competition. However, we documented reduced levels of WPT basking post-removal, which may reflect a behavioral shift attributable to the lower density of the turtle community. WPT body condition also increased after we removed RES, consistent with either indirect or direct competition between WPT and RES and providing the first evidence that RES can compete with a native turtle in the wild. We conclude that the negative impacts on WPT basking by RES in natural contexts are more limited than suggested by experiments with captive turtles, although wild WPT do appear to compete for food with introduced RES. Our results highlight the importance of manipulative field experiments when studying biological invasions, and the potential value of RES removal as a management strategy for WPT.

scholarly journals No correlation between neonatal fitness and heterozygosity in a reintroduced population of Père David’s deer

2013 ◽  
Vol 59 (2) ◽  
pp. 249-256 ◽  
Author(s):  
Yan Zeng ◽  
Chunwang Li ◽  
Linyuan Zhang ◽  
Zhenyu Zhong ◽  
Zhigang Jiang
Keyword(s):  
Birth Weight ◽  
Neonatal Mortality ◽  
Microsatellite Loci ◽  
Mammal Species ◽  
Species Of Conservation Concern ◽  
In Captivity ◽  
In The Wild ◽  
Père David’S Deer ◽  
Genetic Bottlenecks ◽  
Conservation Concern

Abstract Considering the severe impacts of genetic bottlenecks and small numbers of founders in populations of reintroduced animals, it is necessary to study inbreeding and its effect on fitness in species of conservation concern. Père David’s deer is one of few large mammal species extinct in the wild but safely preserved in captivity. Its specific background gives us the opportunity to study the relationships between heterozygosity and neonatal fitness in relocated populations. We employed five microsatellite loci to explore heterozygosity-fitness correlations in a population of Père David’s deer at the Beijing Milu Ecological Research Center. We observed associations between microsatellite-based variables sMLH, IR, MD2 and HL, and two components of fitness expressed early in life (birth weight and the neonatal mortality of 123 Père David’s deer calves born over six consecutive years). We found that neonatal mortality was 19.1% ± 7.6%, not higher than the 19% or 18% reported in other ungulates. The heterozygosity of calves was not associated with neonatal mortality, nor birth weight. Our study implies that low genetic variability of microsatellite loci has no overt effect on birth weight and neonatal mortality in reintroduced populations of Père David’s deer.

Climatic Variables Differentially Influence Neotropical Plant Species of Conservation Concern

2021 ◽  
pp. 1-16
Author(s):  
Pablo Antúnez ◽  
Christian Wehenkel ◽  
Collins Byobona Kukunda ◽  
José Ciro Hernández-Díaz
Keyword(s):  
Plant Species ◽  
Climatic Variables ◽  
Species Of Conservation Concern ◽  
Conservation Concern

Using impact assessment study designs for addressing impacts to species of conservation concern

2012 ◽  
Vol 36 (3) ◽  
pp. 450-456 ◽  
Author(s):  
Mike E. Marshall ◽  
Ashley M. Long ◽  
Shannon L. Farrell ◽  
Heather A. Mathewson ◽  
Michael L. Morrison ◽  
...  
Keyword(s):  
Impact Assessment ◽  
Impact Assessment Study ◽  
Assessment Study ◽  
Species Of Conservation Concern ◽  
Conservation Concern ◽  
Study Designs

scholarly journals White-nose syndrome-related changes to Mid-Atlantic bat communities across an urban-to-rural gradient

BMC Zoology ◽  
2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Sabrina Deeley ◽  
Joshua B. Johnson ◽  
W. Mark Ford ◽  
J. Edward Gates
Keyword(s):  
The United States ◽  
Myotis Lucifugus ◽  
National Capital Region ◽  
Conservation Areas ◽  
White Nose Syndrome ◽  
Species Of Conservation Concern ◽  
National Capital ◽  
Park Service ◽  
Bat Conservation ◽  
Conservation Concern

Abstract Background White-nose Syndrome (WNS) has reduced the abundance of many bat species within the United States’ Mid-Atlantic region. To determine changes within the National Park Service National Capital Region (NCR) bat communities, we surveyed the area with mist netting and active acoustic sampling (2016–2018) and compared findings to pre-WNS (2003–2004) data. Results The results indicated the continued presence of the threatened Myotis septentrionalis (Northern Long-eared bat) and species of conservation concern, including Perimyotis subflavus (Tri-colored bat), Myotis leibii (Eastern Small-footed bat) and Myotis lucifugus (Little Brown bat). However, we documented a significant reduction in the abundance and distribution of M. lucifugus and P. subflavus, a decrease in the distribution of M. septentrionalis, and an increase in the abundance of Eptesicus fuscus (Big Brown bat). Conclusions Documented post-WNS M. septentrionalis recruitment suggests that portions of the NCR may be important bat conservation areas. Decreases in distribution and abundance of P. subflavus and M. lucifugus indicate probable extirpation from many previously occupied portions of the region.

scholarly journals Deep genetic structure at a small spatial scale in the endangered land snail Xerocrassa montserratensis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Cristina Català ◽  
Vicenç Bros ◽  
Xavier Castelltort ◽  
Xavier Santos ◽  
Marta Pascual
Keyword(s):  
Genetic Structure ◽  
Land Snail ◽  
Snail Species ◽  
Small Spatial Scale ◽  
Geographic Ranges ◽  
Genetic Groups ◽  
Species Of Conservation Concern ◽  
Conservation Actions ◽  
Conservation Concern ◽  
Single Locality

AbstractSpecies with small geographic ranges do not tend to have a high genetic structure, but some land snail species seem to be an exception. Xerocrassa montserratensis, an endangered land snail endemic to Catalonia (northeastern Iberian Peninsula), is an excellent model to study the processes affecting the phylogeography of specialized species of conservation concern. This species is restricted to xerophilous stony slopes and occurs within a small and fragmented area of ca. 500 km2. We sequenced the COI barcode region of 152 individuals from eight sites covering the entire range of the species. We found four genetic groups mostly coincident with their geographic distribution: a central ancestral group containing shared haplotypes among five localities and three groups restricted to a single locality each. Two of these derived groups were geographically and genetically isolated, while the third and most differentiated group was not geographically isolated. Geomorphologic and paleoclimatic processes during the Pleistocene can explain the divergence found between populations of this low dispersal species with historical fragmentation and secondary contacts. Nonetheless, recent passive large dispersal through streams was also detected in the central group. Overall, our study uncovered four evolutionary units, partially matching morphologically described subspecies, which should be considered in future conservation actions.

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