Habitat Selection by a Threatened Desert Amphibian
Hinderer, Ross (2021), Habitat Selection by a Threatened Desert Amphibian, Dryad, Dataset, https://doi.org/10.5061/dryad.h9w0vt4gp
Aim. Habitat degradation and fragmentation are major drivers of amphibian declines. The loss of environmental features that allow for movement between water sources may be particularly detrimental for amphibians in arid environments. Climate changes will increase the importance of microhabitats to amphibians. Enhancing areas to facilitate movement may be a necessary conservation strategy for many animal species that depend on wetlands, including federally-threatened Chiricahua leopard frogs (Lithobates chiricahuensis). Habitat preferences of this frog species are not well understood. We sought to better understand fine-scale habitat selection, to inform conservation of Chiricahua leopard frogs.
Location. We conducted our study on the Ladder Ranch, a privately-owned working bison ranch in New Mexico, USA that supports a large proportion of the remaining Chiricahua leopard frogs in the state.
Methods. We attached radio transmitters to 44 frogs during summer 2014. We located each frog daily for up to 8 weeks (median = 30 days). We assessed fine-scale habitat selection by comparing characteristics at each frog location and a random location 5 meters away using conditional logistic regression.
Results. Frogs preferred features that likely reduce desiccation, even after accounting for the presence of water. Frogs selected areas with more low-lying cover, especially aquatic vegetation and woody debris, a tree overstory, and a mud substrate.
Main Conclusions. We recommend managing potential movement corridors for Chiricahua leopard frogs by ensuring the presence of muddy creek bottoms, woody debris, riparian overstory, low-lying ground cover, and pools. Microclimates created by these features seem especially valuable given warming temperatures and modified precipitation regimes, resulting in decreased surface water, soil moisture, and vegetation cover. Retaining or creating preferred habitat features and microclimates in areas between water sources may increase connectivity among isolated populations of Chiricahua leopard frogs and could improve persistence and recovery of other water-obligate species in arid landscapes.
We captured Chiricahua leopard frogs and fitted them with radio transmitters during summer 2014 on the Ladder Ranch, New Mexico, USA. We relocated frogs with radio telemetry and quantified habitat variables at the frog's location, within a 1m-diameter circle centered on the frog. We used a random number generator to determine a random compass bearing (1-360), and walked 5m on that bearing and performed a second habitat quantification at that random location.
The dataset is formatted as pairs of locations. The first spreadsheet line of a DATE/TIME/FROGID unique combination is the frog location. The second line of that unique DATE/TIME/FROGID combination is the random location 5m away from the frog. UTME and UTMN, cartesian coordinates for exact frog locations, have been removed from the dataset because of the sensitive nature of endangered animal locations. Please contact the authors if exact locations are needed.
DATE: Date in DD-MMM-YY format
TIME: Time of relocation in 24 hr format
FROGID: unique identifier for each frog. FROGIDs with multiple numbers (e.g., 503/017) were a single frog fitted with multiple transmitters.
USE: A binary indicator for the locations used by a frog (1) or the random location 5m away (0).
UTME/UTMN: location of frog and random location. Removed for protection of endangered species.
WATER: binary indicator for presence of standing or flowing liquid water at the location (y=yes/n=no)
DIST: if location was not in water, distance to the nearest source of liquid water.
SUBSTRATE: dominant substrate class at the location (within the 1m-diameter circle) See article text for condensation of variable categories.
FCOVERPCT: the percentage of low-lying cover (originally called "frog cover") at each location, quantified by visual estimation.
FCOVERTYP: the type of low-lying cover (originally called "frog cover") at each location. See article text for condensation of variable categories.
OCOVERTYP: the type of overstory cover at each location. See article text for condensation of variable categories.
OCOVERPCT: the percentage of overstory cover at each location, quantified by visual estimation.
PHOTO: binary indicator for if a photo was taken of the location (### = photo number/n=n)
NOTES: any notes on the location from the observer.