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

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.

Download Full-text

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

Current Zoology ◽

10.1093/czoolo/59.2.249 ◽

2013 ◽

Vol 59 (2) ◽

pp. 249-256 ◽

Cited By ~ 4

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.

Download Full-text

Monitoring invasive mammalian predator populations sharing habitat with the Critically Endangered Puerto Rican parrot Amazona vittata

Oryx ◽

10.1017/s0030605305001286 ◽

2005 ◽

Vol 40 (1) ◽

pp. 95-102 ◽

Cited By ~ 12

Author(s):

Richard Engeman ◽

Desley Whisson ◽

Jessica Quinn ◽

Felipe Cano ◽

Pedro Quiñones ◽

...

Keyword(s):

Puerto Rican ◽

Habitat Type ◽

Critically Endangered ◽

Mammal Species ◽

Forest Sites ◽

The World ◽

Mammalian Predators ◽

In The Wild ◽

Amazona Vittata ◽

Black Rats

Critically Endangered Puerto Rican parrots Amazona vittata are one of the rarest birds in the world. Several exotic mammal species capable of preying on Puerto Rican parrots cohabit the Caribbean National Forest with the only wild population of these parrots. We used tracking plates, monitoring blocks and trapping to index black rats, small Indian mongooses and feral cats in parrot habitat and in public-use areas in the same habitat type. We had high trap success for black rats at all sites (42% of all sites combined), among the highest reported in the world. Rat response to monitoring (nontoxic bait) blocks was universally high, regardless of ground or tree placement. Mongooses were present at all sites, with a greater proportion of plates tracked within the forest than at public-use sites. Cats were present at all forest sites and one of the public-use sites. Presence of the three species did not appear to be linked to human disturbance. Because only 30–40 Puerto Rican parrots survive in the wild, with as few as three pairs nesting in 2002, we concluded that the abundance and pervasiveness of exotic mammalian predators poses a greater threat to the parrots than has been generally acknowledged. This is evidenced by mammalian predation during recent parrot breeding seasons, including six fledglings taken by mongooses and one nest failure from rats during 2000–2003.

Download Full-text

Parentage Assignment Reveals Multiple Paternity in the Critically-Endangered Guatemalan Beaded Lizard (Heloderma Charlesbogerti)

10.21203/rs.3.rs-831359/v1 ◽

2021 ◽

Author(s):

Brenna A Levine ◽

Robert Hill ◽

Joseph Mendelson ◽

Warren Booth

Keyword(s):

Genetic Diversity ◽

Mating System ◽

Prediction Models ◽

Multiple Paternity ◽

Parentage Analysis ◽

Multiple Sexual Partners ◽

Species Of Conservation Concern ◽

In The Wild ◽

Genetic Mating System ◽

Conservation Concern

Abstract Within captive management programs for species of conservation concern, understanding the genetic mating system is of fundamental importance, given its role in generating and maintaining genetic diversity and promoting opportunities for sperm competition. If a goal of a conservation program is reintroduction, knowledge of the mating system may also inform prediction models aimed at understanding how genetic diversity may be spatially organized, thus informing decisions regarding where and which individuals should be released in order to maximize genetic diversity in the wild population. Within captive populations, such information may also influence how animals are maintained in order to promote natural behaviors. Here we investigate the genetic mating system of the Guatemalan beaded lizard, Heloderma charlesbogerti, a member of a genus lacking such information. A group of adult male and female H. charlesbogerti were co-habited for five years during the species perceived breeding season. Through genomic parentage analysis, 50% of clutches comprising multiple offspring were found to result from polyandry, with up to three males siring offspring within single clutches. Furthermore, males were found to be polygamous both within and across seasons, and females would exhibit promiscuity across seasons. As such, within this captive environment, where opportunities existed for mating with multiple sexual partners, the genetic mating system was found to be highly promiscuous, with multiple paternity common within clutches. These findings are novel for the family Helodermatidae, and the results have broader implications about how reproductive opportunities should be managed within captive conservation programs.

Download Full-text

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

Australian Journal of Zoology ◽

10.1071/zo10023 ◽

2010 ◽

Vol 58 (4) ◽

pp. 234 ◽

Cited By ~ 7

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.

Download Full-text

Greater Sage-Grouse survival varies with breeding season events in West Nile virus non-outbreak years

The Condor ◽

10.1093/ornithapp/duab002 ◽

2021 ◽

Author(s):

Lindsey A Parsons ◽

Travis J Runia ◽

Geoffrey P Vincent ◽

Andrew J Gregory ◽

Jonathan A Jenks

Keyword(s):

West Nile Virus ◽

South Dakota ◽

Breeding Season ◽

Mosquito Species ◽

Sage Grouse ◽

West Nile ◽

Species Of Conservation Concern ◽

Mammalian Predators ◽

Antibody Titers ◽

Conservation Concern

Abstract Greater Sage-Grouse (Centrocercus urophasianus) is a species of conservation concern and is highly susceptible to mortality from West Nile virus (WNV). Culex tarsalis, a mosquito species, is the suspected primary vector for transmitting WNV to sage-grouse. We captured, radio-tagged, and monitored female sage-grouse to estimate breeding season (April 15 to September 15) survival, 2016–2017. Deceased sage-grouse were tested for active WNV; live-captured and hunter-harvested sage-grouse were tested for WNV antibody titers. Additionally, we trapped mosquitoes with CO2-baited traps 4 nights per week (542 trap nights) to estimate WNV minimum infection rate (MIR). Eight sage-grouse mortalities occurred during the WNV seasons of 2016 and 2017, 5 had recoverable tissue, and 1 of 5 tested positive for WNV infection. Survival varied temporally with sage-grouse biological seasons, not WNV seasonality. Survival was 0.68 (95% CI: 0.56–0.78; n = 74) during the reproductive season (April 1 to September 15). Mammalian predators were the leading suspected cause of mortality (40%), followed by unknown cause (25%), avian predation (15%), unknown predation (15%), and WNV (5%). These results indicate WNV was not a significant driver of adult sage-grouse survival during this study. Three sage-grouse (1.9%; 95% CI: 0.5–5.9%) contained WNV antibodies. We captured 12,472 mosquitoes of which 3,933 (32%) were C. tarsalis. The estimated WNV MIR of C. tarsalis during 2016 and 2017 was 3.3 and 1.6, respectively. Our results suggest sage-grouse in South Dakota have limited exposure to WNV, and WNV was not a significant source of sage-grouse mortality in South Dakota during 2016 and 2017. Based on our finding that a majority of sage-grouse in South Dakota are susceptible to WNV infection, WNV could potentially have an impact on the population during an epizootic event; however, when WNV is at or near-endemic levels, it appears to have little impact on sage-grouse survival.

Download Full-text

Unusual Record of Nocturnal Activity of the Critically Endangered Atelopus varius at Protected Zone Las Tablas, Costa Rica

Revista Latinoamericana de Herpetología ◽

10.22201/fc.25942158e.2018.1.2 ◽

2018 ◽

Vol 1 (1) ◽

pp. 55

Author(s):

Diego Alejandro Gomez Hoyos

Keyword(s):

Costa Rica ◽

Critically Endangered ◽

Herbaceous Plant ◽

Diurnal Activity ◽

Nocturnal Activity ◽

Important Species ◽

Critically Endangered Species ◽

Species Of Conservation Concern ◽

Conservation Concern ◽

Protected Zone

Atelopus varius is a critically endangered species distributed in Costa Rica and Panama. It has diurnal activity and at night it rests on vegetation or in crevices, with no apparent nocturnal activity. Herein, we report an unusual nocturnal activity for the species at Las Tablas Protected Zone, Costa Rica; we observed an individual on an herbaceous plant at night, performing slow movements while feeding on ants. Despite A. varius being one of the most well-known species of the genera, there are still poorly studied aspects of its natural history. Therefore, we propose to lead research efforts on the nocturnal behaviour of A. varius, with the purpose of filling knowledge gaps for this important species of conservation concern.

Download Full-text

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

Wildlife Research ◽

10.1071/wr15198 ◽

2016 ◽

Vol 43 (4) ◽

pp. 298 ◽

Cited By ~ 4

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.

Download Full-text

Microhabitat preference of the critically endangered golden mantella frog in Madagascar

Herpetological Journal ◽

10.33256/hj29.4.207213 ◽

2019 ◽

pp. 207-213

Author(s):

Wayne Edwards

Keyword(s):

Mixed Models ◽

Environmental Variables ◽

Canopy Cover ◽

Critically Endangered ◽

Microhabitat Use ◽

Tree Roots ◽

Pet Trade ◽

Breeding Sites ◽

In Captivity ◽

In The Wild

The golden mantella (Mantella aurantiaca) is a critically endangered (CR) frog, endemic to the eastern rainforestsof Madagascar. Although the species is very popular in the pet trade and widely bred in captivity, its specific habitat requirements in the wild are poorly understood. Ten forested sites in the Moramanga district of Madagascar were surveyed for microhabitat and environmental variables, and the presence or absence of golden mantellas in quadrats positioned along transects in the vicinity of breeding sites. Mixed models were used to determine which variables best explained microhabitat use by golden mantellas. Sites where golden mantellas were found tended to have surface temperatures of 20-23 ˚C, UVI units at about 2.9, about 30 % canopy cover, and around 30 % herbaceous cover. Within sites, golden mantellas preferred microhabitats that had 70 % leaf litter coverage and relatively low numbers of tree roots. This information can be used to improve the identification and management of habitats in the wild, as well as to refine captive husbandry needs.

Download Full-text

Reproductive rates of wild and captive Vancouver Island marmots (Marmota vancouverensis)

Canadian Journal of Zoology ◽

10.1139/z05-056 ◽

2005 ◽

Vol 83 (5) ◽

pp. 664-673 ◽

Cited By ~ 14

Author(s):

Andrew A Bryant

Keyword(s):

Reproductive Performance ◽

Vancouver Island ◽

Social Constraints ◽

Wild Populations ◽

Wild Female ◽

In Captivity ◽

In The Wild ◽

Reproductive Rates ◽

Using Data ◽

Old Females

I evaluated reproductive rates of the critically endangered Vancouver Island marmot (Marmota vancouverensis Swarth, 1911) using data from captive and wild populations over the 1980–2004 period. Results were similar to those reported for other alpine-dwelling marmots, including the closely related Marmota caligata (Eschscholtz, 1829) and Marmota olympus (Merriam, 1898). Most females in captivity first bred at age 3 or 4 (Tbreed = 4.3 years, SD = 1.15, n = 9), an age not significantly different from that observed in the wild (Tbreed = 3.6 years, SD = 1.2, n = 16). Numbers of pups weaned per litter were similar in captivity (Npups = 3.0, SD = 1.4, n = 25) and in the wild (Npups = 3.4, SD = 1.1, n = 58). Females were capable of weaning pups in consecutive years (46.4%, n = 13) but often skipped 1 year (39.3%, n = 11) or 2 years (14.3%, n = 4) between litters. Two-year-old females weaned pups infrequently (Pbreed = 0.09, n = 43) and older females were far more likely to breed (Pbreed = 0.40, n = 200); in neither case were significant captive-wild differences found. The oldest breeding female was 10 years old, but sample sizes for marmots older than 8 years were small and maximum breeding age may be underestimated. Between-litter intervals in captivity (Tbetween = 1.4 years, SD = 0.7, n = 11) were significantly shorter than in the wild (Tbetween = 1.9 years, SD = 0.7, n = 17). Sex ratios of weaned pups did not differ from 1:1 in the wild (female/male = 1.04) but were significantly skewed towards males in captivity (female/male = 0.56). I conclude that reproductive performance in Vancouver Island marmots is limited both by body condition and social constraints.

Download Full-text

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

PeerJ ◽

10.7717/peerj.7444 ◽

2019 ◽

Vol 7 ◽

pp. e7444 ◽

Cited By ~ 2

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.

Download Full-text