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

UBAP lead and ornithologist Anastasia Rahlin presents on railway ecology

UBAP program lead and ornithologist Anastasia Rahlin was invited to present at the 2023 Railroad Environmental Conference (RREC). Her talk, titled “Railway Ecology: Using Railway Corridors to Restore Native Habitats and Preserve Biodiversity,” discussed the emerging field and made recommendations for future research.

There are 48,000 hectares of railway right of way in Illinois, 774,000 hectares in the US, and 4,122,000 hectares globally which could be managed for wildlife conservation.

Rahlin discussed where research efforts should be focused”

Collisions and wildlife crossings

    • Continue fencing high-speed railways
    • Create wildlife passages for low-vagility species

Habitat Restoration

    • Maintain native plant diversity in verges
    • Focus on restoring grasslands – appear more susceptible to invasive species

Species monitoring and management

    • Expand focus from large mammals
    • Standardized, repeated surveys needed to establish baselines
    • Need for robust occupancy and abundance models
    • Multi-year monitoring before and after construction/expansions
    • Investigate life history parameters for well-studied species
    • Adaptive management framework

Future Research

    • Before-After-Control-Impact (BACI) designs
    • Establish experimental vegetation plots along verges
    • Take advantage of novel technology

INHS PaCE Lab members present at The Wildlife Society meeting

Two members of the INHS PaCE Lab presented at The Wildlife Society annual conference November 5-9 in Louisville, KY.

scientific poster about point of care device to monitor birdsUBAP program leader and ornithologist Anastasia Rahlin presented a poster “Using Point of Care devices to assess Marsh and Sedge Wren food limitation”

Abstract:
Food limitation affects wildlife health and survival, may stem from differences in body condition or habitat quality between sites, and may be exacerbated by extreme weather events. Blood metabolites have previously been used as a food limitation index in birds. To assess changes in blood metabolites in marsh and sedge wrens, we used Point of Care devices to measure blood glucose, ketones, and triglyceride levels as short and long-term food limitation indices. We collected blood samples from wrens in May-August 2022 and 2023 in two Illinois DNR state parks and one dedicated conservation area in the Chicagoland Wilderness region over the duration of the breeding season. Our data indicate short-term food limitation may increase as the breeding season progresses for both Marsh and Sedge Wrens. Ongoing modeling will test whether body condition (age, fat and muscle scores), habitat quality (wetland extent and composition), or extreme weather (drought or flooding) best predicts glucose, ketone, and triglyceride levels over the course of the breeding season. Our findings will provide insights into physiological responses of sedge and marsh wrens to food limitations, and highlight the utility of using POC devices to rapidly measure blood metabolites in the field with minimal impacts to study species. An additional goal of this research is to use blood metabolite data to identify high-quality sites for migratory birds; our data will be used to evaluate the effectiveness of conservation areas at providing high-quality habitat. This work will inform wetland and wet meadow management strategies for migratory birds.


scientific poster about pond breeding amphibian egg massesARC program leader Ethan Kessler presented a poster “Reproductive output of forested ephemeral wetland-dependent amphibians across a modified landscape”

 

Abstract:
Forested ephemeral wetlands (FEW) support diverse communities of habitat specialist species across the eastern United States, including wetland-breeding amphibians (WBA). Due to their reliance upon FEW for breeding habitat, the location of FEW on the landscape influences population dynamics and distribution of WBA. Generally, FEW are difficult to detect due to their small size and position under the canopy, however, recent technological advances provide the ability to remotely detect FEW with great accuracy. Improved FEW detection methods enable a better understanding of how FEW characteristics and distribution influence WBA presence and abundance. We counted egg masses of two widespread WBA species, Spotted Salamanders and Wood Frogs, at 231 FEW on public lands in southern Illinois using a double observer methodology from 2020–2023. We then used local and landscape characteristics to predict egg mass abundance for each species. We found egg mass counts were highly correlated between observers for each species, but the presence and abundance of egg masses were not highly correlated between the two species. For Spotted Salamanders, we found a positive effect of wetland size on egg mass abundance but found no effect of canopy cover within a 200 m buffer. Conversely, for Wood Frogs we found no effect of wetland size, but egg mass abundance was positively associated with canopy cover within 200 m of FEW. Results from this study will provide a foundation for the estimation of WBA across broad geographic scales using discrete maps of FEW.

 

New paper on Baron’s mantella frog, co-authored by Devin Edmonds

frog on moss
Mantella baroni photo by Devin Edmonds

INHS PaCE Lab PhD candidate Devin Edmonds co-authored a recent paper on habitat features of Baron’s Mantella Frog. Tantely Rasoarimanana (Université d’Antananarivo) and Olivier Marquis (Paris Zoo) led the collaboration with the NGO Man and the Environment. The study aimed to identify what microhabitat features explain the presence of Baron’s mantella frog (Mantella baroni) and also estimate their population sizes in Vohimana Reserve, eastern Madagascar. We found that leaf litter depth and the number of small trees in a quadrat were important habitat features; deeper leaf litter and fewer small trees explained if M. baroni was present.