A Survey of the Reptiles and Amphibians at the University of Georgia Costa Rica Field Station in San Luis de Monteverde, Costa Rica

Reptiles and amphibians are experiencing declines across the globe. In Monteverde, Costa Rica, these declines and their underlying causes have been relatively well studied since the early 1990s, and many protected areas have been set aside to conserve these species. However, thorough surveys of the herpetofaunal diversity in these areas have been scarce over the last 20 years. We conducted a survey of all reptile and amphibian species at the University of Georgia Costa Rica (UGACR), a field station in San Luis de Monteverde. Herein, we present an annotated checklist of the 48 species (35 reptiles and 13 amphibians) that we encountered. While we did not find any exceptionally rare or endangered species, the number of species we encountered is disproportionately high given the small plot of land occupied by UGACR. This underscores the importance of conducting regular diversity surveys in biodiversity hotspots as a means to better inform conservation efforts.


Introduction
Over the past several decades, documenting the diversity and abundance of amphibians and reptiles has become a pressing matter for conservation (Stuart et al. 2004;Mendelson III et al. 2006;Whitfield et al. 2007). Since the First World Congress of Herpetology in 1989, scientists have become increasingly concerned about what has come to be known as the "worldwide amphibian decline problem" (Stuart et al. 2004), and although it has received less attention, reptiles are declining globally in a similar fashion (Whitfield Gibbons et al. 2000;Whitfield et al. 2007). As with most animal groups, reptiles and amphibians are susceptible to human-induced activities such as deforestation and habitat alteration, but herpetofaunal species are disappearing at much faster rates than would be predicted if these were the only variables at play (Stuart et al. 2004;Whitfield et al. 2007). Such endangerment and/or extinctions often occur in areas that have appeared to remain relatively unaltered over the years, where groups like birds have continued to thrive (Pounds et al. 1997). One likely culprit is disease; the pathogenic chytrid fungus Batrachochytrium dendrobatidis Longcore et al., which causes the disease chytridiomycosis, has caused mass mortality in frogs across the globe (Berger et al. 1998). Moreover, the fungi Ophidiomyces ophiodiicola (Sigler et al.) and Batrachochytrium salamandrivorans Martel et al. have begun wreaking havoc on snakes (Lorch et al. 2016) and salamanders (Martel et al. 2014), respectively. When coupled with the effects of an increasingly warming climate, once-immune ecosystems may soon have the optimal conditions for such fungi to thrive, promoting more outbreaks (Carey and Alexander 2003;Lips et al. 2003;Pounds et al. 2006). Now more than ever, it is critically important to document reptile and amphibian diversity so that we can understand how much biodiversity we still have left and where our conservation efforts should be focused.
The Monteverde region of Costa Rica was one of the first areas implicated with amphibian declines. Around 1987, there was a huge population crash of the Golden Toad Incilius periglenes (Savage, 1967) and the Harlequin Frog Atelopus varius (Lichtenstein & Martens, 1856) in the Monteverde Cloud Forest Reserve, after which these species were not found again (Pounds and Crump 1994). Following intensive surveys of the area between 1990 and 1994, it was found that approximately 40% of the frog species had disappeared (Pounds et al. 1997). While other reptile and amphibian groups were not studied as intensively in Monteverde, data from La Selva Biological Station, a lowland site only about 90 km away, indicated that densities of leaf litter reptiles and amphibians have declined by approximately 75% since 1970 (Whitfield et al. 2007). Clearly, the threat to herpetofaunal biodiversity in Monteverde and the surrounding areas is enormous, and, at least for frogs, well-documented. The high number of preserves and protected areas in Monteverde is an excellent step in the conservation of these species; however, documentation of which species currently inhabit the region remains scarce.
In Monteverde, there are three major protected areas: the Monteverde Cloud Forest Reserve, the Santa Elena Reserve, and the Children's Eternal Rainforest. In addition, there are several smaller protected areas, including the Curi-Cancha Reserve, the Aguti Reserve, and Selvatura Park, as well as a network of private reserves. We conducted an intensive survey for reptiles and amphibians at one such private reserve, a field station formerly known as the University of Georgia Costa Rica (UGACR). In this paper, we present an annotated checklist of the 48 species (35 reptiles and 13 amphibians) that we encountered during our survey.

Methods
Study site. The UGACR property (center point at 10.2827°N, 084.7985°W) is about 1100 m above sea level on the Pacific slope of the Tilarán Mountain Range and shares boundaries with both the Monteverde Cloud Forest Reserve and the Children's Eternal Rainforest, making it an excellent location to document herpetofaunal biodiversity. The property is comprised of roughly 63 ha of land, including 50 ha of secondary forest, 9 ha of farmland, 3.8 ha of manicured lawns and campus buildings, an area bisected by a river, and a large botanical garden (Fig. 1). Originally purchased in 2001 as an  international satellite campus for the University of Georgia, UGACR hosted study abroad students, ecotourists, naturalists, and researchers from around the world. As an aside, the property was sold to the Council on International Educational Exchange (CIEE) in 2019 and therefore no longer exists under the name UGACR; however, the research presented in this paper was conducted before CIEE's purchase of the land, so we will refer to the site as UGACR here. We conducted our herpetofaunal survey from 4 January 2018 to 18 September 2018, but survey effort varied considerably across that timespan, with the most intensive surveying occurring in the first five months. All research was conducted under research permit number M-P-SINAC-PNI-ACAT-019-2018 from the Ministerio de Ambiente y Energia in Costa Rica. We were not permitted to collect voucher specimens, so we primarily relied on photographs for documentation (all of which are available from JDC upon request). Our surveying approach was multifaceted, leveraging traditional sampling methods as well as citizen science and chance encounters to maximize the number of animals encountered. While exact geographic coordinates were recorded for every observation, we have designated different "zones" on the property (Fig. 1)  Trapping methods. We relied on three commonly-used types of traps for catching reptiles and amphibians: drift fences with pitfall traps and funnel traps (Farallo et al. 2010;Greenberg et al. 1994), coverboards (Grant et al. 1992), and frog tubes (Boughton et al. 2000). Trap sites contained one large drift fence array, five coverboards, and five frog tubes. Two sites (one in the forest interior and one in the forest edge) were located in Forest Zone 1, one site was located in the Riparian Zone, and one site was located in Pasture Zone 2. Traps were open from 20 March 2018 to 20 September 2018, and all traps were checked every 1-2 days. Any reptile or amphibian caught was removed from the trap, identified, photographed, and released <10 m from where it was captured. Most individuals were released immediately, but those that were too difficult to identify in the field were briefly taken back to the lab, identified, and then returned to the area from which they were captured. All animals were minimally handled to reduce stress, and none were kept in the lab for more than a few hours. Our drift fence arrays consisted of two thin sheets of aluminum flashing (each 2.45 m long and 0.61 m high) that were arranged in a straight line and zip-tied upright to wooden stakes planted in the ground. In between the two fences, we placed a funnel trap, and on each extreme end of the line of fences, we buried a five-gallon bucket (the pitfall traps). Our custom-built funnel trap was essentially a 1 m × 0.4 m × 0.42 m wooden box with an openable screen lid on the top and a circular hole (7.5 cm in diameter) cut out of one side to serve as a funnel. Attached to the hole on the interior of the trap was a short cylindrical tunnel made of plastic and metal screening and tilted upward at an approximately 30° angle, allowing animals to enter the trap but making it difficult to exit. Drift fence arrays are effective when placed in areas where animals move from one location to another; because the smooth metal fencing cannot easily be climbed, drift fences encourage animals to try to move through the gap in between the fences or to navigate around the outside of them. In the gap, we bent the edge of the fences toward the small opening in the funnel trap to guide animals into it. We positioned the buckets so that animals trying to go around the fence would fall in and not be able to climb out. In both funnel and pitfall traps, we placed leaf litter and a moist sponge to provide cover and prevent desiccation, and we drilled small holes in the bottom of each trap to keep them from filling with rainwater.
Coverboards and frog tubes serve as artificial refuges for animals. In our study, coverboards consisted of pieces of 1 m × 0.82 m sheet metal that were placed on the ground. These objects not only provide cover but may also provide ideal temperature and moisture conditions for certain reptiles and amphibians (Halliday and Blouin-Demers 2015). We haphazardly placed these coverboards within each trapping site (accounting for the limits imposed by the landscape), but we attempted to vary the amount of shadiness and leaf litter each was subjected to, and we made sure the substrate under each allowed it to lay flat against the ground. Frog tubes were made of PVC pipe (31 cm long, 6 cm diameter) with a cap on one end, which were strapped to trees and oriented vertically with the opening facing upward. Frog tubes were also placed haphazardly within trapping sites, but we varied their height from the ground (1.25-2 m) and the size and species of the tree to which they were attached. Both coverboards and frog tubes were checked by simply looking under/in them to see if an animal was using them as refuge.
Encounter surveys and chance encounters. While the aforementioned trapping methods can prove effective for many terrestrial species, there are many species that simply cannot be sampled in this way. Notably, arboreal snakes and lizards may not come down to drift fences or use artificial refuges, and particularly large snakes and frogs may be able to simply climb or jump out of pitfall traps. As such, we routinely conducted visual and aural encounter surveys in which we searched for reptiles and amphibians by sight and by sound (calling frogs), respectively. We searched for animals in all habitats throughout the property of UGACR, looking in trees, in the leaf litter, around ponds, in sunny basking spots, and under natural cover objects like rocks and logs. We conducted these surveys at all times of day and frequently at night. In addition, we documented all "chance encounters" that occurred. These were observations of reptiles and amphibians that happened while not explicitly surveying for them. Given that the authors of this paper were all involved in the Resident Naturalist program at UGACR (see Citizen Science section below) and active researchers on various projects in the field, chance encounters of reptiles and amphibians were a near-daily occurrence.
Citizen science. As a field station located in the biodiversity hotspot that is Monteverde, Costa Rica, UGACR attracted ecotourists and study-abroad students from as far as Europe and as close as San José. In turn, UGACR had a thriving Resident Naturalist program, in which interns with a bachelor's degree or higher would live on the campus and lead natural history-oriented workshops, lectures, activities, and hikes for all visitors. Coupled with the fact that UGACR saw a very high number of visitors during the time period in which our herpetofaunal survey took place, this meant that at any given time, it was likely that there was a large number of people exploring the property with the explicit goal of observing nature. We leveraged this unique opportunity by inviting fellow resident naturalists and guests to submit observations of reptiles and amphibians while they stayed on campus. To ensure the accuracy of identifications, we asked these citizen scientists to provide photographs, details, and geographic coordinates of all observations that they submitted. Identifications were only confirmed if the photo evidence was unambiguous. Citizen scientists were not asked nor encouraged to touch or harass the wildlife in any way.
Identification. All reptiles and amphibians encountered during the survey were identified using the field marks presented in the publications of Hayes et al. (1989), Savage (2002), Savage andBolaños (2009), andLeenders (2016). The latter field guide by Leenders is by far the most up-to-date of these publications, but it only includes amphibians. Luckily, Leenders (2019) recently published a companion field guide for reptiles, and although we were unable to use this guide during the survey period, we were able to use it to later confirm our reptile species, for which we had photographs of nearly all observations.

Results
During our herpetofaunal survey of UGACR, we documented a total of 48 species (Tables 1-3). This included 13 amphibian species from seven families: Plethodontidae (1 species), Bufonidae (1 species), Craugastoridae (3 species), Eleutherodactylidae (1 species), Hylidae (4 Table 1. List of all amphibian species documented during the survey period, as well as the specific areas in which they were found and the number of times they were encountered. See Figure 1 for zone locations. A dagger symbol ( †) denotes an unconfirmed species. Duellmanohyla rufioculis X 4 Isthmohyla pseudopuma X 1 Smilisca sordida X X 5

Ranidae
Rana forreri X X X X X 127 Rana warszewitschii X X X X 13

Strabomantidae
Pristimantis ridens X X X X 29 Table 2. List of all lizard species documented during the survey period, as well as the specific areas in which they were found and the number of times they were encountered. See Figure 1 for zone locations. A dagger symbol ( †) denotes an unconfirmed species.  Table 3. List of all snake species documented during the survey period, as well as the specific areas in which they were found and the number of times they were encountered. See Figure 1 for zone locations. A dagger symbol ( †) denotes an unconfirmed species.  (Tables 2, 3). We recorded a total of 659 individuals, but we note that this number (and those in the subsequent Materials examined sections) may be inflated due to multiple observations of the same individual(s), which we had no way of marking after each observation. It is also worth noting that zones were surveyed with highly unequal frequencies; observations in the Western Zone and Ecolodge Zone came strictly from chance encounters and citizen science, while all other zones were actively surveyed by the authors on a near-daily basis.

Annotated list.
Here, we present an annotated list for all 48 species we encountered at UGACR. Taxonomy and nomenclature follow the most recent field guides by Leenders (2016;2019), although we recognize that the elevation of former Colubridae subfamilies to family level is particularly controversial (Zaher et al. 2019). With the exception of a few members of the frog genus Craugastor Cope, 1857 and the lizard genus Anolis Daudin, 1802, identification of most reptile and amphibian species that we encountered was straightforward. This was aided by the fact that most genera present in Monteverde are represented by only one or two species. In the following sections, we include important field marks for identification and notes on distribution in Costa Rica, as well as whether or not the species is likely to be confused with another in Monteverde. Four species, which we denote with a dagger symbol ( †), are considered unconfirmed because we do not possess photographs of them from UGACR; nevertheless, we are confident in their identification and explain in their respective sections how we came to the conclusion of their presence. Unless otherwise noted, the descriptions of diagnostic traits and distributions are based on Leenders (2016;2019) and Savage (2002). For information on which species were recorded in which of our designated zones of UGACR, consult Tables 1, 2, and 3.

Family Plethodontidae
Oedipina uniformis Keferstein, 1868 Figure  Remarks. Formerly considered subspecies of Lampropeltis triangulum (LaCépède, 1788), which has been split. Based on range maps alone, any large milk snake at UGACR would likely be assumed Lampropeltis abnorma, which inhabits Pacific slope of Costa Rica. However, both individuals encountered during survey were black with very faint red bands, suggesting individuals were Lampropeltis micropholis transitioning to older age and displaying ontogenetic change from ringed to black. This does not occur in Lampropeltis abnorma (Leenders 2019). High-quality photos could not be obtained, as both encounters involved fast-moving individuals that were only recorded by phone video. Venter cream anteriorly and tan to reddish brown posteriorly. Eyes large, pupils round. Sharp ridge over top of eyes. Dorsal scales smooth. Distribution. Common in dry habitats on Pacific slope in northwestern and western Costa Rica. Remarks. Leenders (2019) notes that this species is found from sea level to 450 m elevation in Costa Rica, but according to Savage (2002), it is found from sea level to 1435 m. Figure  Identification. Very large snake (total length up to 250 cm) often encountered on ground in wide range of habitat types. Extremely variable in color pattern, but adults often dark brown or bluish-gray on dorsum and yellow on venter. Some individuals with red to brown markings on dorsum. Well-known defensive display involves flattening of head, puffing of neck, and gaping/striking. Distribution.  Distribution.

Discussion
To our knowledge, this is the first peer-reviewed publication of a broad-scale herpetofaunal biodiversity survey in Monteverde in 20 years. Despite the high number of protected areas in the region, we were only able to find published herpetofauna lists for the Monteverde Cloud Forest Reserve (Hayes et al. 1989;Pounds and Fogden 2000). According to the most recent of these, 60 amphibians and 101 reptiles have been documented at the reserve. Species that we encountered that are not on this list (after accounting for taxonomic changes) include Dendropsophus microcephalus, Coleonyx mitratus, and Hemidactylus frenatus. This is not particularly surprising, as UGACR is lower in elevation than the Monteverde Cloud Forest Reserve; the first two species are more commonly found in lowland areas, and the third is invasive (Leenders 2016(Leenders , 2019. At first pass, it may seem that UGACR's 48 herpetofauna species pales in comparison to the 161 in the Monteverde Cloud Forest Preserve, and much of this could potentially be attributed to the difference in habitat quality (primary vs secondary forest; Barlow et al. 2007) or the difference in sheer area of habitat (MacArthur and Wilson 1967). However, it is also unclear how accurate the Monteverde Cloud Forest Reserve's list is at the current time. For example, it includes both Incilius periglenes and Atelopus varius, neither of which has been seen in decades (Pounds and Crump 1994). We point this out not to be critical, but because it undermines any meaningful comparisons between the two lists. It also emphasizes the need for more current sampling of Monteverde, especially considering its known implications with herpetofaunal declines. While we are unable to compare our list to that of any nearby reserves, we did find several relevant research projects conducted by undergraduates taking part in tropical ecology courses with the Council on International Educational Exchange (CIEE). Some of these projects have involved herpetofaunal surveys in the Monteverde region, with scopes ranging from all reptiles and amphibians to a single genus (Benjamin 2003;Place 2005;Schlimm 2007;Brossard 2011;Siebert 2017). Although the reports of these projects are not peer-reviewed, they offer valuable data regarding the presence or absence of species in the area. Generally speaking, the species that these projects have documented greatly overlap with those in our list, with the majority of discrepancies likely explained by differences in sample site elevation (many of the projects were done at higher elevations in Monteverde, which have notably different species assemblages than UGACR). However, at least two projects involved reptile and amphibian surveys in and around UGACR's property (a third is cited by Benjamin (2003), but the referenced report does not appear to be available anywhere). From 20 October 2003to 14 November 2003, Benjamin (2003 found 14 species along transects at UGACR and an additional nine species in nearby San Luis. Of those 23 total species in the report, our survey documented 18. A more recent project targeted amphibian diversity at UGACR, using pitfall traps and drift fences to document two species of frogs (Brossard 2011), one of which was not documented in our survey. The species that were found during these two projects but not during our study were Bolitoglossa robusta (Cope, 1894), Rana vaillanti Brocchi, 1877, Anolis woodi (Dunn, 1940), Holcosus undulatus (Wiegmann, 1834), Imantodes cenchoa (Linnaeus, 1758), and Leptodeira annulata (Linnaeus, 1758). Although we are unable to confirm the accuracy of these observations based on the reports alone, we suspect that Rana forreri may have been mistaken for Rana vaillanti, as R. forreri was not documented in Brossard (2011) but is abundant in the exact location where the traps were installed, and because R. vaillanti is not known to occur above 880m in elevation anywhere in Costa Rica (Savage 2002;Leenders 2016). Nevertheless, it is entirely plausible that the other five of these species could be present on the campus of UGACR. We may have been unable to detect these species due to timing (wet vs dry season) or simply due to the low detection probability of many of these species (see below). In any case, we hope that our data can be combined with data generated during such CIEE projects to get a better sense of the species present in Monteverde.
Our results also highlight a fact that is often overlooked in herpetofaunal conservation studies: snakes are particularly hard to sample. Of the 23 species of snakes we encountered, nearly 70% of them were observed fewer than four times, and over 40% were observed only once. This may be attributable to low population densities for many species, but it could also be influenced by low detection probabilities (De Fraga et al. 2014), potentially inadequate (or nonexistent) trapping methods, or sampling bias towards diurnally active, non-fossorial snakes. These are important factors to consider when assessing trends in the presence and/or density of snake species in an area; are "observed" changes in biodiversity true changes or rather artifacts of detection probabilities and sampling biases? Moreover, it is worth noting that we had high proportions of infrequently encountered species even during a relatively long survey (more than eight months), suggesting that any sort of rapid assessment of biodiversity may have seriously underrepresented the true number of species present. We present these numbers and words of caution for snakes, but the same could be said for many secretive, nocturnal, and/or fossorial taxa.
Finally, our findings demonstrate the importance of Monteverde as a local biodiversity hotspot within the world-renowned biodiversity hotspot that is Costa Rica. Because the UGACR campus covers approximately 0.63 km 2 , and Costa Rica as a country encompasses roughly 51,100 km 2 , this means that UGACR takes up approximately 0.001% of the country's land. On UGACR's property, the forest is not particularly "pristine", and there are agricultural fields, roads, buildings, and manicured lawns interspersed throughout. Despite all of this, on this tiny sliver of land, we documented 13 amphibian and 35 reptile species, representing 6.3% and 14.3% of Costa Rica's amphibian and reptile diversity, respectively (Leenders 2016(Leenders , 2019. This disproportionately high diversity of reptiles and amphibians compared to the small fraction of land area encompassed by UGACR speaks to the ideal combination of environmental conditions that facilitate the persistence of these species in the Monteverde region of Costa Rica. It also suggests that human-altered areas like UGACR are perhaps not the dead zones they were once considered to be and are certainly worthy of study, despite being relatively neglected by ecologists (Martin et al. 2012). Other wellknown areas of diversity throughout Costa Rica, both inside and outside of protected areas, would benefit from similar up-to-date surveys of biodiversity. Moreover, the importance of not only conducting such surveys, but also getting them published, cannot be understated, as they are invaluable to understanding the status and trends of local populations and are therefore critical to making well-informed conservation decisions. Despite much evidence of species in decline, there is clearly much left to conserve, and biodiversity surveys like these are how we know where to start.