Canopies, the Final Frog-tier: Exploring responses of a specialist treefrog to prescribed fire in a pyrogenic ecosystem

doi:10.21203/rs.3.rs-1511197/v1

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Canopies, the Final Frog-tier: Exploring responses of a specialist treefrog to prescribed fire in a pyrogenic ecosystem

https://doi.org/10.21203/rs.3.rs-1511197/v1

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Background:

Pine flatwoods of the Southeast United States evolved with frequent wildfires. Land managers today mostly use prescribed burns to control fuels but also to restore historical lightning-caused wildfires dynamics. Though coarse outcomes of this practice are well-understood, fine scale impacts on many animal assemblages are still being explored. Frogs, for example, have upland and wetland requirements, limited mobility, and skin susceptible to desiccation and chemicals. Treefrogs, which are typically nontargeted for management, spend most of their lives in uplands away from water. When fire approaches, these animals will escape to an unburned area, hide in place, or die.

Results:

We assessed impacts of prescribed fire on the dynamics of an upland flatwoods specialist, the pinewoods treefrog Dryophytes femoralis using a replicated before-after-control-impact field experiment. Using single rope technique and climbing equipment, we set PVC pipes as treefrog refugia at 3m, 6m, 9m, and 9+m in Longleaf Pines, Pinus palustris (n=12 tress). Three trees were selected in each patch per treatment: two unburned and two burned patches during the 2021 burning season (n=4 patches). Every two weeks between March and September we checked pipes for frogs and assigned them unique Visible Implant Elastomer (VIE) marks. We obtained data from 76 individuals with an additional 198 recaptures. Using mark-recapture methods and mixed linear models with Bayesian framework, we modeled abundance, survival, and vertical movement. Survival and recapture were comparable among treatments, but abundance, new frogs and probability of moving up or down a tree varied. Frogs in trees in burned units were more likely to stay in place and less likely to descend to lower heights. We observed an increased probability of finding new frogs and more abundance in trees after a fire compared to unburned controls.

Conclusions:

We found the prevailing mechanism for resiliency to fire for pinewoods treefrogs was migration up large pines, then recolonization of the shrub layer when it regreens post-fire. This finding substantiates conclusions from other works that integrity of mature pines is key to sustaining native biodiversity. Future work and management should consider the three-dimensional structure of habitat when developing burn prescriptions and study designs.

Amphibians

canopy

Dryophytes femoralis

fire effects

Florida

mark-recapture

pine flatwoods Pinewoods treefrogs

prescribed fire

single-rope-technique

Populations are constantly changing spatially and temporally, even within a single ecosystem. They shift seasonally, annually, and in response to biotic and abiotic pressures. Investigation into factors that influence population dynamics across the landscape is therefore a constant focal point for ecological researchers, conservation biologists, and land managers. For example, disturbances can have impacts on populations at different spatial and temporal scales (Odum et al. 1979, Pickett and White 1985, Menges and Marks 2008, Quintana-Ascencio et al. 2018). Fire, a common global disturbance, may have an immediate impact via mortality or emigration, but also have longer lasting impacts due to habitat alteration, resource availability, and chemical leaching (Wilbur and Christensen 1983, Russel et al., 1999, Noss and Rothermel 2015, Jones et al., 2020).

Fires occur worldwide, and in some regions and ecosystems this natural disturbance is frequent enough that it becomes a major driver of the population dynamics for many species (Kauffman 2004, Noss 2013). Prescribed or controlled fires are increasingly utilized as a proxy for these more hazardous and unpredictable natural wildfires. In the United States (US), prescribed fire is one of the most common methods used by land managers to attempt to restore this critical ecological process while safely reducing fuel loads and burn intensity on natural lands (USDA and USDI 2002, Pilliod et al. 2003, Pausas and Keeley 2014).

The pine savannas of southeastern U.S are closely linked to fire. These ecosystems evolved with relatively short lightning-induced fire return intervals of about 2–5 years (Komarek 1968, Barnett 1999, Noss 2013). Many of the constituent species in these fire-prone ecosystems require frequent fire for reproduction, and most recover quickly from burns (FNAI 2010). While optimal fire intervals for ecosystem persistence are relatively well understood, the potential for fine-scale modifications to accommodate species responses to fire is an important consideration for scientists and land stewards (Noss 1987, 1996). Fine-scale adjustments within coarse-level conservation and management plans have been effectively implemented for many species, such as pre-burn understory thinning for cavity trees of red-cockaded woodpeckers Picoides borealis Vieillot (Williams et al. 2006), deliberate hardwood patch protection for Sherman’s fox squirrel Sciurus niger shermani (Perkins et al. 2008) and vehicle buffers to prevent burrow collapse for gopher tortoises Gopherus polyphemus Daudin (Smith et al. 2015).

Plants native to these systems have numerous strategies for persisting in pyrogenic ecosystems, including but not limited to seed banks, underground storage organs, fire-resistant bark, and resprouting (Outcalt 2000, Noss 2013, and those cited within). Consequently, and appropriately, fire management is mainly based on outcomes for plants (Driscoll et al. 2010). While plants are forced to endure a fire, animals have different options. When a fire occurs, or any other disturbance, animals face three main pathways which can be generalized to escaping, hiding in place, or dying (e.g., Peterman et al. 2011). While each of these mechanisms occurs simultaneously at the individual-level, each can have different population impacts. Populations that go through a mass mortality or significant exodus event may experience a temporary or permanent extirpation. When the prevailing mechanism is to hide in-place, however, we should expect a local population to be present immediately post-disturbance. Studies that focus on individual- and population-level mechanisms are therefore necessary to fully understand fire-influenced dynamics (Russel et al. 1999, Driscoll et al. 2010).

Given that fire is an essential process that maintains structural, compositional, and dynamic properties in these ecosystems, we need to understand how nontarget groups respond. Amphibians are typically not considered for fire management, yet they are good models for looking at prescribed fire impacts. Amphibians have limited mobility, are sensitive to chemical perturbations, require special microhabitats, and have been experiencing enigmatic declines around the globe (Blaustein et al. 1995, Stuart et al. 2004). An overwhelming majority of amphibian studies to date have focused on collecting data at breeding events in wetlands, which often represents only a snapshot of this group’s life histories (Boughton et al., 2000, Pilliod et al. 2003, Klaus and Noss 2016, Robertson et al. 2018). Treefrogs, in the family Hylidae, are particularly interesting because they require both upland and wetland ecosystems for their life cycle but spend most of their lives in those uplands and out of water. Furthermore, this group is unique among amphibians because they readily ascend into the canopy layer of trees. Studies and anecdotal observations note that at least some age classes of treefrogs in the southeast prefer to be above the ground (Wright and Wright 1949, Boughton et al. 2000, Windes 2010, I.N. Biazzo personal observations). To the best of our knowledge, no studies have looked at hylid occupancy above the 4m height in the US (i.e., above the shrub or undergrowth layer) and considered impacts of fire or other disturbances on these vertical dynamics.

We used a before-after-control-impact experimental design combined with mark-recapture to examine impacts of prescribed fire on apparent survival, movement, and abundance of treefrogs in pine flatwoods in central Florida, U.S. To observe treefrogs, which use natural cavities to avoid desiccation and predation, we set polyvinyl chloride (PVC) pipes in trees as artificial refugia which they could enter and exit at will (Buchanan 1988, Boughton et al., 2000, Schurbon and Fauth 2003, Zacharow et al. 2003, Glorioso and Waddle 2014). While the pine flatwoods are home to four native treefrog species in central Florida, 99% of individuals observed in our study were one specialist species, the pinewoods treefrog (Dryophytes (Hyla) femoralis Bosc, Fig. 1), (Klaus and Noss 2016). We focused on the following questions regarding this specialist species: 1) What are the base-level pre-fire abundance, apparent survival, and movement of frogs in trees? 2) Does fire change these parameters? 3) If so, then which is the prevailing mechanism of population change during a fire?

Study Site

We focused our study on pine flatwood ecosystems around depression marshes in Disney Wilderness Preserve (DWP) Poinciana, FL, USA (Fig. 2). DWP is a 4654-ha preserve owned and managed by The Nature Conservancy (TNC) and is part of the Greater Everglades watershed. The preserve is mainly composed of pine flatwoods with interspersed hammocks, scrub, cypress swamps, and freshwater marshes. In 1992, the property, then a cattle ranch, was purchased as a restoration mitigation site by the Walt Disney World Corporation and then later transitioned to TNC. Ecological and hydrological restoration, which included filling in a heavily ditched landscape and improving the hydroperiod, occurred from 1994 to 2012 and was deemed successful in 2011 (TNC 2011). Current management includes ecologically motivated growing season prescription burns on a 2–3 year interval. Temperatures recorded by an on-site National Ecological Observatory Network (NEON) station ranged from 8°C to 35°C through the study (March – September), and monthly precipitation was 4.5, 111.4, 16.6, 230.3, 207.7, 125.9, and 104.4 mm respectively.

Experimental Design

We established experimental plots by selecting 4 depression marshes to use as focal points and identified upland buffer zones of ~ 100m around each marsh. All plots were part of separate, larger pre-determined fire management units with different burn schedules. Two units, Unit Scrub West (SW) and Unit 4 (4), were scheduled to burn in the spring or summer of 2021 while the other units, Unit Scrub East (SE) and Unit 3N (3N), burned a year before the study in 2020 and served as experimental field controls (Fig. 2). The burn crews at DWP conducted controlled burns on the experimental fire Unit 4 on April 16, 2021, and Unit Scrub West on July 21, 2021.

In each upland zone, we selected three Longleaf Pine trees (Pinus palustris, Mill.), ensuring a minimum distance of 10m between trees, for a total of 12 pines. We chose living trees with a minimum height of 9m, a safe anchoring branch in the crown (for rope), and no obvious lightning or rotting damage, if more than three trees met these criteria within the management unit then we randomly chose three. Between February 15–21, 2021, we attached PVC pipes as treefrog refugia in each pine tree (Buchanan 1988, Boughton et al., 2000, Schurbon and Fauth 2003, Zacharow et al. 2003, Bartareau 2004, Glorioso and Waddle 2014). All pipes were 2 feet long, 1.5-inch diameter, 330 psi, white, bottom-capped, fitted with a drainage hole at 10cm from the bottom and hole for screw at the top, and secured to the tree with a drill and bungee so they faced inward towards the marsh. We set pipes at approximately 3m, 6m, 9m, and, when tall enough, 9 + m (Fig. 3) using a single rope technique (SRT) with rapid ascension and descension equipment (RAD). The final height category, 9 + m, varied per tree based on the tallest safe attachable height, which ranged from 10-12m. This resulted in 3–4 pipes per tree, and 45 total PVC pipes across the 12 pines. We draped paracord over the anchor branches to minimize subsequent rope setup time.

Data Collection

We started sampling on March 5, 2021, approximately two weeks after the setup. This latency period allows frogs time to discover the refugia on the trees and is consistent with similar studies (Boughton et al. 2000, Zacharow 2003, Myers et al. 2007, Windes 2010). We continued sampling every two weeks until September 5, 2021, near the peak of Florida hurricane season, which resulted in 14 sampling events. One person ascended each tree using the SRT-RAD setup, inspected pipes for treefrogs, carefully emptied frogs into large transparent plastic bags, safely secured the bags in their backpack, emptied the pipe of debris and water, replaced the pipe, and descended the tree with the frog(s). Once on the ground we measured snout-vent length (SVL) and marked individuals with a unique combination of visible implant elastomer markers (VIE, Northwest Marine Technology, Olympia, Washington, US). We marked frogs on 1–4 locations ventrally: left or right inner thigh or inner calf. If a frog was a recapture, then we recorded its color combination and no further marks were given. All processing was done through the plastic bag, and we released frogs at the base of the study tree after the climbing equipment was disassembled. Total handling was typically only a few minutes.

We also collected data on environmental factors including tree height, distance to nearest wetland, number of branches (> 12 inches) off main trunk, and percent crown height. We measured neighboring tree density 5m, 10m, and 15m from the study tree. Finally, using pictures taken with a fisheye lens attachment on a cellphone, we estimated percent shade at each pipe opening (Table 1).

Table 1

Summary of physical environmental data. Charted numbers are means based on the three study trees in each unit.
Environmental Unit Comparisons
	Height (m)	Branches 0-3m	Branches 3-6m	Branches 6-9m	Branches 9–9 + m	Branches > 9 + m	% Crown
Unit 4	15.17	0.00	1.00	4.67	5.33	4.33	45.00
Unit 3N	11.83	0.00	2.33	8.00	3.00	5.00	47.50
Unit SE	13.50	0.33	3.00	6.67	2.50	5.67	37.50
Unit SW	14.17	0.00	1.00	5.00	5.00	4.67	49.17
	Wetland Distance(m)	Nearest Neighbor (m)	Trees within 5m	Trees within 10m	Trees within 15m	Mean DBH of neighbors	DBH (cm)
Unit 4	23.33	6.60	1.00	8.33	7.33	10.33	42.13
Unit 3N	71.67	15.00	0.00	0.00	2.67	16.53	37.93
Unit SE	64.00	2.83	1.67	7.00	15.00	12.45	36.30
Unit SW	27.67	6.83	0.33	3.67	14.33	8.49	34.17

Table 2: Total pinewoods treefrogs captured per height (3m, 6m, 9m, and 9+m) and experiment treatment.

Table 3. WAIC statistics for abundance and new frog models. We evaluated responses as a function of Fire, Time, and Tree. † Indicates random effect. The WAIC differences (dAIC) and relative model weights (W) are based on comparisons of each model with the most likely model.

Model	Total Frogs		New Frogs
	dAIC	Weight	dAIC	Weight
Fire + Time (†) + Tree (†)	0.0	1.00	0.0	0.48
Null (mean only)	122.7	0.00	0.72	0.34
Time (†) + Tree (†)	13.2	0.00	2.0	0.18

Analyses

We used generalized linear mixed models with a Bayesian framework to examine prescribed fire impacts on treefrog abundance. We tested hypotheses based on combinations of fire conditions (pre-fire, post-fire, and post-fire regreen), with and without fire during the sampling, burn management unit (location), and sampling time effects. We evaluated survival, recapture, and vertical transitions based on the mark-recapture data. To evaluate the vertical transitions, we used a categorical multi-state approach where the ‘states’ were the different height levels (3m, 6m, 9m, and 9 + m) in the trees. To facilitate computation, we incorporated weak priors for survival based on estimates from work on a congeneric in central Florida and based on an ongoing study in this same system (Windes 2010, Biazzo et al., unpublished data). Models were run using R version 3.4.4 (R Core Team, 2019) and version 2.18.0 of Stan (Stan Development Team. 2018, Carpenter et al., 2017) based on modified code for population analyses based on Kéry and Schaub 2012.

Environmental factors

To establish basic comparisons of our experimental units we combined the physical environmental data for each tree and used them to make averages for each experimental unit (Table 1). Overall, trees in each unit had similar average heights, 11.8-15.2m, proportions of crown layer, 37.5–49.2%, DBH 34.2-42.1cm, few to no branches below six meters, and few to no neighboring trees within 5m radius. There was more variation in average distance to the nearest wetland, 23.3-71.7m, and trees within 15m radius.

Mark-recapture

We observed 76 pinewoods treefrogs in this study, with 198 recaptures. For the multistate analysis, we excluded only one data point because a recaptured frog had marks that were faded to the point that we could not figure out its identity. Of the 198 recaptures, only one frog moved between trees (distance ~ 65m) and it only moved once. While this may be an artifact of the low number of trees chosen for this study, it is consistent with the high site fidelity observed in other studies that showed little to no movement among trees (Boughton et al. 2000, Pittman et al. 2008, Windes 2010, Biazzo et al., unpublished data). Furthermore, on several occasions we observed treefrogs upon release navigating back to their tree of origin and up to their most recent pipe refugia in the tree, often climbing past lower pipes. The overall average capture history among all individuals was 3.6 captures and among those recaptured it was 5.3 total captures. Only 30 frogs (39%) were never recaptured, and the longest capture history was 14 captures which spanned the entire duration of the study and every sampling event. Finally, we observed two dead recaptured treefrogs that likely died due to smoke from a fire. They were found in the tree with the highest burn scar along with several dead green anoles, Anolis carolinensis, but none showed visual signs of fire damage. We observed 56 frogs captures at 3m, 52 at 6m, 85 at 9m, and 81 at 9 + m, and 11 out of 12 trees had frogs at some point in the study (Table 2).

Abundance

The model most likely explaining abundance variation included fire as a fixed effect and both time and tree location as random effects (Table 3). This was consistent for total frogs (i.e., new frogs and recaptured frogs, n = 273) and for just new frogs (n = 76). The weight of the Null, or mean-only model, is close to the fire impact model. This is likely an artifact of the relatively small sample size of new frogs (n = 76). Still, we can infer from the experimental design that there were more frogs in trees with fire and there was higher probability of finding new frogs in trees shortly after a fire, and after a few weeks the probability during the regreening period shifts back towards estimates for no-fire conditions. These changes were not observed in the control units that did not burn (Figs. 4,5).

Multistate models

We used a multi-state model with diffuse priors to estimate apparent survival, recapture rate, and vertical movement rates. The model produces survival and recapture estimates for each state, or height, and transition probabilities for each possible transition from time t to time t + 1. Among all heights, we estimated apparent survival between 77–84% in burned and 62–91% in unburned areas, and recapture rates of 60–85% and 63–88% respectively. We observed changes in movement probabilities between burned and control treatments. Two major trends emerged. First, frogs in trees in burned units were more likely to remain at one height instead of moving up or down to other heights (Fig. 6, diagonal). Next, frogs in crowns of the tree responded similarly in both treatments, but frogs in burned units were still less likely to descend to lower heights. In other words, movement between the top two heights, 9m and 9 + m, was similar across the study (Fig. 6, bottom right) but there was variation in the probability of descending to lower heights of 3m and 6m.

Human populations increasingly encroach on natural lands, expanding the wildland urban interface. Accompanying this encroachment is an increased need for careful stewardship and restoration of the remaining natural lands to achieve conservation and management objectives (Soulé 1985). However, we can only manage for what we understand. Here we show how a specialist treefrog species uses vertical space in pine flatwoods, and how that use changes when a prescribed fire occurs. By utilizing an existing fire management regime, we expanded current understanding by transcending typical time-since-fire monitoring and creating an experiment with fire as a treatment and with comparable field controls.

Prescribed fire effects can be direct, indirect, and vary spatiotemporally (Russell et al 1999). We have a working understanding of prescribed fire impacts at the ecosystem-level and for certain target species, but we need to consider how traditionally nontargeted groups respond to reinforce or modify our efforts. The already complex combinations of fire effects, and subsequent management decisions, could intensify as ecosystems buffer other anthropomorphic threats. The taxonomic groups that are vulnerable today may not be the same ones that are at risk in the future. One attractive solution to mitigate fire effects and optimize biodiversity is to burn in a mosaic, but more research is needed to make sure conservation objectives are commensurate with the multi-dimensional mosaics we create across the landscape (Bradstock et al. 2005, Parr et al. 2006).

The canopy layer of the landscape is often ignored by researchers in most systems, likely due to the technical difficulties involved, but this is problematic as they represent significant portions of the habitat for many species, can be biodiversity hotspots, and contribute to biogeochemical process (Rinker et al 2001, Lowman 2009, Nakamura et al. 2017). In addition to treefrogs, we incidentally captured anoles, scorpions, spiders, wasps, cockroaches, and other insects, often in large quantities. Habitat for many of these animals, along with epiphytic plants, fungi, and bacteria, includes all three dimensions of the landscape and we should not assume that their dynamics observed on the ground are the same at the top of a tree (Nakamura et al. 2017, and those cited within). In an open canopy, where each mature tree is isolated from other trees, these differences may even be exaggerated. Factors such as weather effects, prey availability, and predation risk could have more extreme trade-offs given the isolation. The pine-dominated ecosystems of the Southeast U.S. do not have the closed canopies of other forests, however, we believe that this patchiness of the canopy layer only adds to an already interesting field of research.

We observed an increase in abundance of frogs in trees after a fire, compared to trees in unburned control plots, providing support for a refugia hypothesis, animals found a way to hide from the disturbance within their habitat by climbing up trees rather than evacuating to an unburned area. These frogs entered our study after the fire, remained for several weeks, then were gradually not seen again. The parabolic shape of this response and lack of an obvious mortality event post-fire suggests these individuals descended back into the ground and shrub layers once the plants regreened, which is consistent with other studies. While sampling at and below breast height in a similar system, Schurbon and Fauth (2003) observed a lower abundance of treefrogs in a burned area compared with areas burned in the previous year. Given the high site fidelity and low death-by fire observed, temporary refugia in the tall trees seems to be a dominant mechanism for this species surviving to fire. This conclusion supports other studies that highlight the importance of maintaining some healthy, mature trees during burns (Williams et al. 2006).

True survival cannot be effectively disentangled from permanent emigration in the multistate models, so we report estimates as “apparent survival” with the understanding that these estimates are inherently underestimated. The high site fidelity in this group suggests apparent and true survival may be similar, but further studies need to confirm this. Still, the multistate models revealed that apparent survival and recapture rates were high during the study and frogs were more likely to stay in higher tree levels than transition to lower ones overall. Apparent survival for burned and unburned units were similar, suggesting low direct mortality from the fires for individuals inhabiting trees.

In addition to the inability to distinguish between true survival and permanent emigration, it is important to recognize the limitations in the design. We fully depended on the use of PVC pipes for treefrog data collection. While effective and commonly used, there are two main associated concerns. First, these are not natural elements of the landscape and therefore introduce artificial biases that could disrupt background behaviors and population dynamics. Second, and relatedly, this sampling design may not be representative of the true population. More specifically, the use of PVC pipes has not been validated as a random and unbiased way to sample a population of frogs. We mitigated these concerns by making sure we used the pipes consistently across all trees and treatments, making any artificial impacts and biases shared throughout. An additional limitation is the study length itself. The study lasted for six months, covering 14 sampling occasions, and in only two burn units in a single preserve, but future work should include more years of data and more sites to better disentangle any spatial, year or seasonal effects from fire impacts.

This work is a significant step in elucidating fire effects on an often-overlooked group of amphibians. Furthermore, this project increases the dimensionality of our knowledge of hylid population dynamics. Treefrogs climb tall pines to escape fire but descend when pre-fire ground conditions return. We observed no major change in survival among treatments, but frogs in trees in burned areas moved less within the tree. We recommend future efforts examine upland dynamics and utilize before-after-control-impact experimental designs when investigating prescribed fire effects (Pilliod et al. 2003). We also suggest future researchers consider supplementing the traditional ground and breeding pond approach to studying treefrogs with techniques like those presented here that can push into the vertical element of their habitat.

ETHICS APPROVAL

This work was reviewed and approved by UCF IACUC PROTO202000065.

CONSENT FOR PUBLICATION

Not applicable.

AVAILABILITY OF DATA AND MATERIAL

The datasets created and analyzed during the study are available from the corresponding author on reasonable request.

COMPETING INTERESTS

The authors declare that they have no competing interests.

FUNDING

Funding for this work was provide by the Joint Fire Science Program Graduate Research Innovation (GRIN) award and the UCF College of Graduate Studies Doctoral Research Support award. Neither funding body had any role in the design of the study, collection, analysis, and interpretation of data, or in preparing the manuscript.

AUTHORS' CONTRIBUTIONS

Both authors made substantial contributions to the conception and design of the work, the acquisition, analysis, and interpretation of data, and have revised the manuscript. Both authors have read and approved the submitted version.

ACKNOWLEDGEMENTS

We thank the staff at the Joint Fire Science Program for funding this work. Special thanks to Beatriz “B” Pace-Aldana, Adam Peterson, Petra Royston, Hannah O’Malley, Dan Cole, and the staff at The Nature Conservancy’s Disney Wilderness Preserve, along with the D4 Lab, Dave Jenkins, John Weishampel, Brean Duncan, John Fauth, Karen Reinemund, Sheri Pearson, Graham Worthy, the Biology Department, and College of Sciences at The University of Central Florida for supporting this research. Thanks also to our volunteers: Rachel Gutner, Jessica Provenzano, Katrina Phillips, Federico López Borghesi, Alexa Trujillo, Chris Long, Miguel Silva, Rachel Weavers, Mo Parupia, Leslie Mosquera, Calli Quire, Jena Osmani, Chealsea Anagnoson, Hanna Rosner-Katz, Vince Marcucci, Josh Layland, Eli Shroeder, Katelyn Crooker, Nat Harrison, Diana Thi, Hailee Quintero, Tom Duchak, Mark Manning, and Tim Biazzo. This work was supported by the Joint Fire Science Program, BLM-National Interagency Fire Center (L20AC00008). The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the opinions or policies of the U.S. Government. Mention of trade names or commercial products does not constitute their endorsement by the U.S. Government.

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Canopies, the Final Frog-tier: Exploring responses of a specialist treefrog to prescribed fire in a pyrogenic ecosystem

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