Raising frogs and advancing science

With over 40% of species at risk of extinction, amphibians are among the most imperiled groups on Earth. The biodiversity hotspot of Madagascar is not immune from this problem with nearly 47% of its endemic frog species at risk.

In 2010, Association Mitsinjo began working with IUCN and the government to develop an amphibian breeding facility. PhD Candidate Devin Edmonds has been working with the facility and their conservation programs. In addition to establishing captive assurance populations, this facility has provided important information on frog reproductive biology. The facility has successfully reared and released captive bred endangered Golden Mantella frogs into created habitat.

A paper, published today, reported on 1,272 captive breeding events from 11 additional frog species, including phenology, clutch sizes, oviposition, and larval development time. This information is often hard to obtain in the field, and these observations were the first described for many of these species.

Most of the species bred seasonally, but one, Mantella betsileanus, bred throughout the year and made up 86% of egg masses. Most species did not require environmental stimuli, aligning their behaviors with natural seasons, however Heterixalus betsileo only bred when placed in a modified rain chamber.

Researchers also learned that Gephyromantis mitsinjo lays eggs on land where tadpoles develop terrestrially within jelly, a behavior previously theorized but never observed.

The findings can help inform other captive breeding programs and increase success of conservation efforts for other imperiled species.

Read the complete paper in Zoobiology: Rakotoarisoa, Justin Claude, Andolalao RakotoarisonSolonirina RasoanantenainaEric RobsomanitrandrasanaSamina Sidonie Sam EdmondsJeanne SoamiarimampiononaEdupsie TsimialomananaSebastian WolfDevin Edmonds. 2024. Captive breeding reveals insights into the ecology and reproductive biology of 11 little-known Malagasy frog species. Zoobiology: https://doi.org/10.1002/zoo.21876

 

New paper on endangered Harlequin Mantella populations

Mantella cowani frog
photo by Devin Edmonds

The Harlequin Mantella is one of Madagascar’s most threatened frog species, known from 13 localities. The small, strikingly-colored frog that inhabits mountainous streams has been impacted by habitat degradation and illegal collection for the pet trade.

As part of a species conservation plan, PhD Candidate Devin Edmonds and his colleagues surveyed 11 of those sites and detected the frog at eight sites. The species is believed extirpated from the other three sites. Knowledge from local community members revealed two previously unknown locations, highlighting the importance of collaboration and engagement with the community.

Based on repeated surveys of three of the sites between 2015 and 2023, these small frogs can live 9 or more years in the wild as adults encountered in 2015 were still alive in 2023.

Despite finding two new sites, the populations are small and the frog is still imperiled. Conservation recommendations include upgrading the species to Critically Endangered. Continued monitoring of populations and habitats, and protection from poaching are necessary to conserve the species.

Read the paper published today in PeerJLife https://peerj.com/articles/17947

Edmonds, D., R.R. Andriantsimanarilafy, A. Crottini, M.J. Dreslik, J. Newton-Youens, A. Ramahefason, C. J. Randrianantoandro, and F. Andreone. 2024. Small population size and possible extirpation of the threatened Malagasy poison frog Mantella cowanii. PeerJ, DOI 10.7717/peerj.17947

 

INHS PaCELab at 2024 Turtle Survival Alliance Symposium

This year’s Turtle Survival Alliance conference was held in Tucson Arizona 2024  July 25-28. Several members of the INHS PaCE Lab presented posters and talks, which we’re excited to share with you.
 
Dr. Dreslik gave a featured presentation during the plenary session,
“Freshwater Turtle and Tortoise Growth: What we know and where to go”
co-authored with Drs Lovich (USGS) and Congdon (Savannah River Ecology Lab).

Dr Dreslik at podiumGrowth is a fundamental life history trait expressed as shape, rate, and size at specific times for individuals in a population. Because energy allocated to competing life demands shifts, all expressions have impactful relationships with other life-history traits. In general, the overall growth pattern of turtles is well understood, but representative studies are decidedly lacking for many species and populations. Additionally, we are building a stronger foundation of the drivers and their consequences on growth; few studies have had the luxury of serially examining populations to determine environmental and habitat related effects. Herein, we present the state of knowledge on growth in freshwater turtles, covering aspects such as pattern, seasonality, determinism, dimorphism, extrinsic drivers, maternal effects, and individuality. Finally, we will provide insight into current analytical advances and direction for future work.


Graduate student Nicholas Dunham presented a poster
“Spatial Ecology of Blanding’s Turtles (Emydoidea blandingii) in an Agricultural Landscape in Northeast Illinois”
co-authored with Ethan Kessler, John Crawford and Michael Dreslik.
Agriculture in Illinois dominates the landscape, leading to widespread alteration of terrestrial and aquatic ecosystems. Much of Illinois’ freshwater wetlands have been heavily channelized and converted into vast networks of ditches in agricultural drainage systems. Thus, these agricultural ditches may represent some of the only available wetland habitats for turtles. A small population of Blanding’s Turtles (Emydoidea blandingii) was discovered living in an agricultural ditch system in Kankakee and Iroquois counties of Northeast Illinois. Blanding’s Turtles use terrestrial and aquatic habitats throughout the season, increasing their mortality risks from farming equipment. To better understand how Blanding’s Turtles utilize an agricultural landscape, we trapped and used VHF radio-telemetry to track 15 individuals (9 females, 6 males) from April to November 2023, totaling 533 locations. Our objectives were to investigate home range sizes, movement rates, and macrohabitat and microhabitat selection by sex and season. The results of our study are preliminary, and data collection will continue from 2024 to 2025. Our results can aid the management of Blanding’s turtles in agricultural-dominated landscapes.

Graduate student Emily Asche presented
“Population Structure of the Declining Western Pond Turtle (Actinemys spp.) Across Thirteen Military Installations in California”
co-authored with Matthew Parry, Thomas Akre, Robert Lovich, and Michael Dreslik.
The Western Pond Turtle (Actinemys spp.) is currently undergoing assessment to be listed as a Threatened species under the Endangered Species Act. It is designated as a species of special concern in California, sensitive/critical in Oregon, and endangered in Washington, indicating an imminent likelihood of listing. Habitat loss, predation, and shell disease have caused significant population declines, yet there remains a scarcity of data necessary for informed management decisions. Understanding the existing population structure of remaining populations is pivotal for initiating effective conservation strategies. We are gathering demographic data from thirteen military installations across their California range to assess the level of concern and identify key management priorities. Data collection spans two seasons, with sampling conducted in week- long intervals using 50 aquatic traps per base, supplemented by relevant data from prior or concurrent studies at each installation. Recorded parameters include body size, life stage, and sex of all individuals to characterize the population structure. Additionally, growth rate and recruitment will be derived from the final dataset. Our study’s objective is to delineate targeted conservation efforts for species recovery.

Rose Arnold presented
“Development of a Detection Model of the Blanding’s Turtle (Emydoidea blandingii) to Guide Conservation Prioritization in Illinois”
co-authored with Michael Dreslik
Woman presenting at podiumLike many turtle species, Blanding’s Turtle (Emydoidea blandingii) populations are declining range-wide due to the synergistic effects of habitat fragmentation, loss, and degradation. In Illinois, Blanding’s Turtle populations are isolated within urbanized or agricultural landscapes, thus hindering migration. Additionally, the status of the species at many historical locations remains unknown, whereby many populations may already be functionally extirpated. Thus, determining the status of populations in Illinois is the paramount conservation priority. Surveys for Blanding’s Turtles require a substantial investment of resources (time, funds, and effort) through trapping and visual searches. Currently, there are few tools for quantitatively determining the effort needed to confirm site occupancy. Here, we construct a detection probability model considering temporal, effort, habitat, weather, and environmental variables. The model will allow surveyors to calculate how much effort is necessary to determine occupancy status for a given site under a given set of conditions. The findings from the initial model sets suggest temporal factors exert the most influence on detection, particularly when compared to weather. However, even in strong-performing models, predicted detection rates remained low.

Chitra Rehka Basyal presented a poster
“Structure and Health of a Freshwater Turtle Assemblage in a Highly Developed Ecosystem”
co-authored with Michael Dreslik, Ny Aina Tiana Rakotoarisoa, Laura Adamovicz, and Matthew Allender
Turtles have important ecological roles in wetlands as omnivores, scavengers, food sources, and nutrient recyclers. Despite such importance globally, their populations are declining, with the proliferation of infectious diseases emerging as a major threat. Our study aims to assess turtle’s community structure and evaluate the physical health of those turtle individuals. We began a turtle capture-mark-recapture survey at a university wetland to study assemblage, composition and individual health. In our first year (2023), we captured 39 turtles of 6 species. Based on the species composition, our study suggests the site may be used for illegal pet releases. We screened 37 individuals for adenovirus, herpesvirus, ranavirus, and mycoplasma using conventional and quantitative PCR. Two species (Painted Turtle [Chrysemys picta] and Red-eared Slider [Trachemys scripta elegans]) were adenovirus-positive, with the virus strain being 99% similar to Sulawesi Tortoise adenovirus. No mycoplasma, Ranavirus, or herpesvirus was detected. Moreover, the Red-eared Slider is likely a natural host of Sulawesi Tortoise adenovirus (STAdV-1). The study forms a baseline for long-term demographic monitoring and health assessments of the turtle assemblage.

New paper on Timber Rattlesnake hibernacula

Timber Rattlesnake at hibernacula

PhD candidate Andrew Jesper has a new paper out today on determining suitable hibernacula for the state threatened Timber Rattlesnake. The initial habitat suitability model was developed based on known hibernacula across the state of Illinois. The model was refined over a series of surveys based on the model and updating the model based on information from the surveys. Habitat suitability models inform land conservation decisions, enabling prioritization of areas most likely to support suitable hibernacula.

ABSTRACT: The dependency on hibernacula for extended periods presents terrestrial reptiles with the challenge of locating thermally adequate hibernacula each winter. Defining the habitat characteristics of hibernacula is crucial for understanding the overwintering requirements and distributions of hibernacula-dependent reptiles, alongside identifying habitats which warrant special conservation concern. Our objectives were to identify the overwintering habitat characteristics of the imperiled timber rattlesnake Crotalus horridus in Illinois, USA, and to determine the distribution of likely hibernacula habitats throughout the state. Due to the initial sparsity of hibernacula records in Illinois, we adopted an iterative habitat suitability modeling process consisting of 3 distinct rounds of Maxent construction and revision. Each round was informed with updated information from model-guided surveys or by building rapport with in-state naturalists and researchers who knew of additional hibernacula locations. We created our final model using 36 hibernacula and identified slope angle (indicative of rock outcrops and shallow soils), topographical position index, forest patch area, and aspect (decomposed into 2 linearized variables: southness and eastness) as important drivers of C. horridus hibernacula habitat in Illinois. Together, the 5 variables and site surveys suggest the suitable overwintering habitat for C. horridus in Illinois is located on south- to southwest-facing outcrops on upper slopes and ridges of larger forest patches. Such habitat is distributed primarily in southern Illinois and throughout the Mississippi River and Illinois River border counties. Our study adds to the current understanding of the species’ overwintering requirements and provides a foundation for future ecological studies, management, and survey efforts throughout Illinois.

Read the full paper in: Jesper, A. C., S.A. Eckert, S.R. Ballard, J.A. Crawford, and M.J. Dreslik. 2024. Distribution and drivers of critical hibernacula for the timber rattlesnake Crotalus horridus in Illinois, USA. Endangered Species Research Volume 53, page 467

UBAP leader A Rahlin presents Chicagoland ornithological research

UBAP leader Anastasia Rahlin presented two talks recently.

In January Rahlin presented “Oak Masting in the Chicagoland Region” at the Cook County Forest Preserve District – Resource Management talk as part of CCFPD’s Environmental Education program.

Rahlin and collaborators have been collecting oak masting data in the Chicagoland region over a seven-year period from 2017-2023. The talk focused on data regarding northern red, white, and bur oaks and discussed the history of oak masting research, outlined potential hypotheses that explain the likelihood of mast seeding events, and explored preliminary model results linking weather factors such as temperature and precipitation to acorn masts.
This study examines the impact of oak masting on Red-headed Woodpecker populations, an acorn caching species. Preliminary analyses linking acorn masts to Red-headed Woodpecker presence/absence and whether masting influences Red-headed Woodpecker overwintering in northern Illinois sites were also discussed.
In February, Rahlin presented  “Investigating Extreme Weather Impacts on Sedge and Marsh Wren food limitation and nesting success” at the McHenry County Forest Preserve District Research Roundup talk series.
Rahlin has been examining how habitat quality and extreme weather events impact marsh and wet meadow species in northern Illinois. Her talk focused on continued efforts to monitor marsh and sedge wren body condition through wren morphometrics and blood metabolites in order to understand how the two species respond to droughts and storms. Rahlin also discussed nesting outcomes for both wren species, as well as avenues for future research.

Three new species of Mantellid frog from Madagascar

Three new species of frogs from Madagascar were described in a paper co-authored by PACE Lab PhD candidate Devin Edmonds, led by researchers at Zoological Institute at Technische Universitat Braunschweig.

The group of frogs, Genus Guibemantis, subgenus Pandanusicola, spend their lives in the Pandanus (screw-pine) trees, which are common in the Andasibe area of Madagascar. They live and reproduce in water that pools in the leaves of the trees. While surveying the trees, the researches observed frogs that did not look like any known species Genetic testing revealed 4 new species for the region, 3 of which were new to science.

frog
Guibemantis rianasoa – Beautiful Waterfall Frog – holotype male
Guibemantis vakoa holotype male
Guibemantis ambakoana paratype female

Read an article in the Miami Herald

Read the full paper at

Hugh Gabriel, Laila-Denise Rothe, Jörn Köhler, Sandratra Rakotomanga, Devin Edmonds, Pedro Galán, Frank Glaw, Richard M. Lehtinen, Andolalao Rakotoarison and Miguel Vences. 2024. Unexpected Diversity and Co-occurrence of phytotelmic Frogs (Guibemantis) around Andasibe, one of the most intensively surveyed Amphibian Hotspots of Madagascar, and Descriptions of Three New Species.  Zootaxa. 5397(4); 451-485. DOI: 10.11646/zootaxa.5397.4.1

New publication on Timber Rattlesnake movement

PACeLab PhD Candidate Andrew Jesper co-authored a new paper with his undergrad research advisor Scott Eckert at Principia College. Jesper and Eckert radio-tracked 29 individual Crotalus horridus (13 female, 16 male) in Jersey County, Illinois.

On average, males move greater daily distances and occupy larger home ranges than females, particularly during the summer when Timber Rattlesnakes find mates. Females dispersed shorter distances from their hibernacula than males. Several snakes were tracked over multiple years, and returned to their same general range each summer. This site fidelity may limit the success of translocating adult individuals.

 

 

Abstract

Understanding the home range of imperiled reptiles is important to the design of conservation and recovery efforts. Despite numerous home range studies for the Threatened timber rattlesnake (Crotalus horridus), many have limited sample sizes or outdated analytical methods and only a single study has been undertaken in the central midwestern United States. We report on the home range size, site fidelity, and movements of C. horridus in west-central Illinois. Using VHF telemetry, we located 29 C. horridus (13 female, 16 male) over a 5-year period for a total of 51 annual records of the species’ locations and movements. We calculated annual home ranges for each snake per year using 99%, 95%, and 50% isopleths derived from Brownian Bridge utilization distributions (BBMM), and we also report 100% minimum convex polygons to be consistent with older studies. We examined the effects of sex, mass, SVL, and year on home range sizes and reported on movement metrics as well as home range fidelity using both Utilization Distribution Overlap Index (UDOI) and Bhattacharyya’s affinity (BA) statistics. The home range sizes for male and non-gravid C. horridus were 88.72 Ha (CI 63.41–110.03) and 28.06 Ha (CI 17.17–38.96) for 99% BBMM; 55.65 Ha (CI 39.36–71.93) and 17.98 (CI 10.69–25.28) for 95% BBMM; 7.36 Ha (CI 5.08–9.64) and 2.06 Ha (CI 1.26–2.87) for 50% BBMM; and 78.54Ha (CI 47.78–109.30) and 27.96 Ha (CI 7.41–48.51) for MCP. The estimated daily distance traveled was significantly greater for males (mean = 57.25 m/day, CI 49.06–65.43) than females (mean = 27.55 m/day, CI 18.99–36.12), particularly during the summer mating season. Similarly, maximum displacement distances (i.e., maximum straight-line distance) from hibernacula were significantly greater for males (mean = 2.03 km, CI 1.57–2.48) than females (mean = 1.29 km, CI 0.85–1.73], and on average, males were located further from their hibernacula throughout the entirety of their active season. We calculated fidelity to high-use areas using 11 snakes that were tracked over multiple years. The mean BBMM overlap using Bhattacharyya’s affinity (BA) for all snakes at the 99%, 95%, and 50% isopleths was 0.48 (CI 0.40–0.57), 0.40 (0.32–0.49), and 0.07 (0.05–0.10), respectively. The mean BBMM overlap for all snakes using the Utilization Distribution Overlap Index (UDOI) at the 99%, 95%, and 50% isopleths was 0.64 (CI 0.49–0.77), 0.32 (CI 0.21–0.47), and 0.02 (CI 0.01–0.05)), respectively. Our results are largely consistent with those of other studies in terms of the influence of sex on home range size and movements. The species also exhibits strong site fidelity with snakes generally using the same areas each summer, though there is far less overlap in specific (e.g., 50% UDOI) high-use areas, suggesting some plasticity in hunting areas. Particularly interesting was the tendency for snakes to disperse from specific hibernacula in the same general direction to the same general areas. We propose some possible reasons for this dispersal pattern.

Read the full article: Eckert, S.A., Jesper, A.C. Home range, site fidelity, and movements of timber rattlesnakes (Crotalus horridus) in west-central Illinois. Anim Biotelemetry 12, 1 (2024). https://doi.org/10.1186/s40317-023-00357-8

 

New paper analyzing long term data on Ornate Box Turtle survival

box turtle
Ornate Box Turtle Photo by D. Edmonds

PaCE Lab doctoral candidate Devin Edmonds has a new paper in the journal Wildlife Biology: “Evaluating Population Persistence of Ornate Box Turtles (Terrapene ornata) at the Northeast Edge of their Distribution.”

This work analyzed 34 years of data from one site and 8 years of data from another to estimate female and juvenile survival and population growth over time. Being able to look at a population over a long period of time provides a better understanding of the population. This study also highlighted the need to protect adult female Ornate Box Turtles if the populations are to persist.

This work was co-authored with members of the Wildlife Epidemiology Lab.

 

Abstract: Turtles and tortoises are among the most threatened vertebrate groups. Their life history is characterized by delayed sexual maturity and a long lifespan, making populations susceptible to decline following perturbations. Despite the urgent conservation need, we are missing estimates of basic demographic traits for many species and populations. The ornate box turtle (Terrapene ornata) is a species lacking crucial demographic data. Many populations are isolated in fragmented habitats, especially in the eastern portion of their range. We carried out long-term capture-mark-recapture surveys on two isolated populations in northern Illinois to estimate population vital rates and project population persistence with deterministic stage-based matrix models. Using 34 years of data, we estimated adult female survival = 0.974 (95% CI: 0.946–0.988) and juvenile survival = 0.867 (95% CI: 0.688–0.951) at our most intensively surveyed site. At a second site using 8 years of data, we estimated adult female survival = 0.897 (95% CI: 0.783–0.954) and juvenile survival = 0.844 (95% CI: 0.551–0.960). Despite seemingly high annual survival rates, populations declined under population projections using mean vital rates. Population growth was most sensitive to adult survival, with increasing sensitivity under more pessimistic scenarios. Our results highlight the importance of long-term demographic studies for threatened species and demonstrate protecting adult female ornate box turtles is critical for ensuring populations persist at the northern edge of their distribution.

Read the full paper:

New paper on more efficiently detecting Kirtland’s Snake

kirtland's snake
Kirtland’s Snake

Recent PaCE Lab graduate Tyler Stewart published a paper on his M.Sc. work creating a species distribution model for the rare and cryptic Kirtland’s Snake, Clonophis kirtlandii. He found that surveys Mid-May to early July when there was high cloud cover, moderate air temperature, and low relative humidity enhanced the detection probability of this species.

 

Abstract

Snakes are difficult to study due to their cryptic coloration, minimal movements, and use of inaccessible habitats. Although well‐timed surveys during a species’ active season can result in higher detection rates and conserve survey resources (i.e., time and money), survey effort may not ensure the detection of rare and cryptic species. Thus, in such instances, a strategic species‐ specific sampling design is needed. The Kirtland’s snake (Clonophis kirtlandii) is a rare, cryptic species assumed to be experiencing range‐wide declines. Naturalists have noted the disappearance of Kirtland’s snakes from various habitats since the early 1970s. The primary objective of our study was to determine detection of Kirtland’s snakes and the environmental and temporal factors influencing detection. We calculated the effort needed to detect individuals at sites by estimating detection probabilities of 3 known Kirtland’s snake populations in Illinois from 2019 to 2021. Based on 77 Kirtland’s snake detections over 226 site visits (34.1%) across 3 study sites, we found that high cloud cover, moderate air temperature, and low relative humidity enhanced the detection probability of this species. The middle of May to the beginning of July was the best time to conduct surveys when detection rates were highest. As our results suggested, it is imperative to establish strategic monitoring programs maximizing conservation resources to document populations for conservation action and range shifts for species of conservation concern, such as Kirtland’s snakes.

Stewart, T. A., A.R. Kuhns, C.A. Phillips, J.A. Crawford, and M.J. Dreslik.  2023. Estimating the effort required to detect Kirtland’s snakes (Clonophis kirtlandii). Wildlife Society Bulletin. http://doi.org/10.1002/wsb.1498