While summarizing data for the two-year report, the ecologist for the Gulf Coast Inventory and Monitoring (I&M) Network often undertakes exploratory projects or considers ancillary data. The progress made on these projects is described in this supplementary materials document. All analyses and inferences made here should be considered preliminary and informal. Formal presentation of these or related results will be in the future trend reports, which are written after three two-year reports, or six years of data collection (i.e., trend report 1 will summarize data for April 2018 – February 2024). The current Supplementary Materials document for monitoring at San Antonio Missions National Historical Park (NHP) contains (1) maps of study site location within the park and site layouts; (2) weather and environmental data summaries; (3) amphibian life history in relation to cover object occupancy; (4) useful references for and amphibian monitoring at San Antonio Missions NHP; and (5) select images of field setting and ID during the reporting period.

Figure SM-1 shows the locations of the three amphibian monitoring study sites at San Antonio Missions NHP, located in the south of the city. The deployment of new boards and pipes for the final design occurred on January 10, 2018, by protocol lead Jane Carlson and crew leader Billy Finney, both of the Gulf Coast Network, with help from Marvin Lutnesky, professor at Texas A&M University San Antonio and his students. The same design of coverboards was deployed in Hospital site (HP), San Juan Mission site (SJ), and West Side site (WS), which consisted of five clusters of 4 coverboards each (Figure SM-2). Installation went as planned, resulting in 60 coverboards deployed between the three sites. A pilot study in these three sites, from 2011-2017, had included PVC pipes as well, but yields were so low that they were ultimately removed from the study design.

1 Figure SM-1. Locations and site sampling layouts for amphibian monitoring in San Antonio Missions NHP. There was also a pilot study at each of these sites, from 2011–2017, and the final sampling protocol at Hospital (HP; previously called array E), San Juan (SJ, previously called array C) and West Side (WS, previously called array F), was implemented in January 2018. This figure was taken from the protocol narrative, Appendix A (Carlson et al. 2018a).

2 Figure SM-2. Approximate arrangement of coverboards (red squares) in clusters along a transect. When there was enough space within the habitat, the transect was linear (WS), but for smaller habitat patches, the transect was curved (SJ and HP).

The Gulf Coast Network collects a wide range of environmental measurements in association with each amphibian monitoring event. These ancillary data are necessary because amphibian occupancy of monitored cover objects is highly variable and influenced, to an unknown degree, by current and past weather conditions. This variability creates a statistical challenge for the network, because weather-driven fluctuations in cover occupancy may mask declines or increases in amphibian abundance caused by anthropogenic stressors, which is of primary interest to the network and park. By using ancillary data in models predicting amphibian occupancy and abundance, the network has a better chance of detecting problematic changes in amphibian abundance during the 6-year trend analyses for focal amphibian species. The environmental variables currently measured or assembled by the network are as follows: • Air temperature and relative humidity at the start and end of each sampling event in each site • Ground surface temperature under each coverboard at the time of sampling • Continuous air temperature and relative humidity measured at half-hour or hourly intervals for all days of the year, recorded by a datalogger located a central location in each study site • Daily rainfall and daily barometric pressure from a weather station at the San Antonio Stinson Municipal Airport (<3 km away from each site) • Documentation of major weather events, including storms or prolonged droughts These data are assembled and organized into a single dataset on the network server, where they are used for preliminary comparisons with amphibian abundance. Although 2-year reports are not used for dissection and 3 interpretation of temporal patterns, several plots of weather data are shown here, including a plot of air temperature over time (averaged between the two sites) and amphibian frequency (Figure SM-3). Over the reporting interval, the continuous weather datasets are mostly complete with only a few data gaps. The network lost some data due to malfunctions in the data loggers themselves or malfunctions in the devices used to download the loggers. For air temperature, relative humidity, barometric pressure and rainfall, the period of interest runs from 4/1/2018 to 2/15/2020. At all three sites, air temperature and relative humidity data were missing from 10/10/18 to 12/11/18. There were a few additional days of missing relative humidity data for SJ alone (9/6/2018 to 10/10/2018). The rainfall and barometric pressure data sourced from the nearby Stinson municipal airport were basically complete for the reporting interval, with only a few missing days of rainfall. In Figure SM-3, the temperature and relative humidity data are average over the three sites when no data are missing. Between April 2018 and Feb. 2020, there were several notable drought and cold events that could have affected amphibian presence, behavior and abundance in the park. Regarding drought, there were three relatively dry periods, beginning with mid-Feb. 2019 to early April 2019, where only 7 mm (0.28 inches) of rain fell over almost two months. For comparison, the 30-year average for rainfall at San Antonio summed over February and March is 105 mm, or 4 inches (1981-2010 data; http://www.prism.oregonstate.edu/normals/). A subsequent dry period was even longer, from July 2019 through mid-October 2019, when only 62 mm (1 inch) of rain fell over three and a half months. This is considerably less than the long-term average for July through Sept., at 203 mm, or 8 inches. After a brief rainy spell in October 2019, it remained fairly dry through to the end of the reporting interval (76 mm or 3 inches falling from November 2019 to Feb. 2020; in comparison, the long-term average for those three months is 186 mm, or 7 inches). Regarding temperature, nights of freezing weather are relevant to park amphibians, given that Rio Grande chirping , in particular, are known to be killed by cold temperatures. Over the reporting interval, there were 24 nights with freezing temperatures (equal to or less than 0˚ C or 32˚ F). There were 3 such days in Nov. 2018, 1 in Dec. 2018, 5 in Jan. 2019, 1 in Feb. 2019, 3 in March 2019, 2 in Nov. 2019, 5 in Dec. 2019, and two each in Jan. and Feb. 2020. The number of freezing nights was fairly evenly divided between the 2018-2019 sampling season and the 2019-2020 sampling season (13 versus 11 nights), but the coldest nights recorded were in the second season, mid-December 2019, with two consecutive nights at -5˚ C (23˚ F). The average daily low from Oct. to Feb. was colder in the 2019-2020 season (8.5˚ C or 47˚ F) than it was in the preceding one (9.7˚ C or 49˚ F).

4 Figure SM-3. Continuous weather data for San Antonio Missions NHP from April 2018-Feb.2020. (A) mean daily minimum and maximum temperatures (three sites averaged) compared to frequency of two amphibian species under monitored coverboards for all three sites combined; (B) daily rainfall (black line) and daily mean barometric pressure (grey line) from the San Antonio Stinson Municipal airport, <3 km away, as well as daily mean relative humidity from the continuous loggers, averaged over the three sites (blue).

The plywood coverboards used in this study are meant to serve as shelter for amphibians, such as would a dead log on the ground. The network uses a fixed number of coverboards that remain in the same locations over time, and they assume that on average, amphibians are occupying them proportionately to their population abundance. As such, when the number of amphibians found under coverboards increases over time, it is inferred that there are more amphibians of that species present at the site overall. Even so, the need for shelter is not constant throughout the year, so occupancy may fluctuate across seasons, independent of population sizes. There may also be differences in environmental conditions among years that cause increased use of cover objects, such as an unusually cold winter. Finally, each species may have its own thresholds and preferences for using cover objects, such that any abundance proxy based on cover object data is not comparable across species. To begin to parse out these effects, the network tests for associations with

5 weather variables, as described above, but also considers life history descriptions from the literature to better understand what drives the various patterns in cover object occupancy. There are life history descriptions below for all three amphibian found under coverboards, but only the first two species are detected often enough to potentially be included in trend analyses after six years of data collection: Gulf Coast ( nebulifer), Rio Grande chirping ( cystignathoides), and Western narrow- mouthed toad (Gastrophryne olivacea). The is the only species (family Bufonidae) known to occur at San Antonio Missions NHP. The Gulf Coast toad, like other toad species, is mainly nocturnal. It emerges from burrows or from under logs or leaf litter to feed during the night, especially when conditions are damp and warm. When temperatures are below 10˚ C (50˚ F), this toad species is rarely seen outside of cover (Dundee and Rossman 1989). Breeding is from April to September, when travel to standing water to find mates and lay . Gulf Coast toads are found in a range of habitats throughout southern Louisiana, eastern Texas and coastal Mississippi, from suburban lawns and gardens, to agricultural areas, to more remote wet hardwood forests. Eleutherodactylus cystignathoides The Rio Grande chirping frog is the only non-native amphibian species monitored by the Gulf Coast Network at San Antonio Missions NHP. This species is native to Mexico and a small section of the Rio Grande valley near Brownsville, Texas. Duran (2004) recorded three individuals of this species in the park in 2002 and 2003, during the park’s amphibian inventory. During the network’s pilot study (2011-2017), the Rio Grande chirping frog was regularly detected in all three sites within the first year of pilot monitoring. This species occurs in leaf litter and under logs or other objects on the ground, which is what the coverboards approximate. Unlike most amphibians in North America, Rio Grande chirping frogs do not depend on standing water to breed. Eggs are laid in April and May in high humidity locations on land, and the young hatch as froglets without a stage. This species is sensitive to cold, so it uses the monitored cover objects more often during the colder months of the year. Gastrophryne olivacea The Eastern narrow-mouthed toad is not a member of the true toad family, but is instead a small, smooth- skinned frog in the family . Like the other amphibians studied here, members of this species are primarily active at night (especially at dusk and early evening) during relatively warm weather. They are fossorial or semi-fossorial, spending much of their time beneath the ground, in moist cracks or crevices. They come to the surface during and just after rain, which is when they are most likely found under coverboards. Like Gulf Coast toads and Rio Grande chirping frogs, they occur in diverse natural and semi- natural habitats, including lawns, gardens, meadows, flooded swamps, marshes and forests. Breeding season is primarily from May to August, usually initiated by rain. Breeding occurs at sites ranging from wetlands to ponds to ditches. Their distribution covers nearly all of Texas and into Oklahoma and Kansas.

Carlson, J. E., R. L. Woodman, W. Finney, W. Granger, J. Bracewell, K. Buhlmann, and M. Segura. 2018a. Monitoring amphibians in Gulf Coast Network parks: Protocol narrative—version 2.0. Natural Resource Report NPS/GULN/NRR—2018/1742. National Park Service, Fort Collins, Colorado. https://irma.nps.gov/DataStore/Reference/Profile/2256511 6 Carlson, J.E., R. L. Woodman, W. Finney, W. Granger, J. Bracewell, K. Buhlmann, and M. Segura. 2018b. Standard Operating Procedures for Monitoring Amphibians in Gulf Coast Network Parks. Gulf Coast Network, Lafayette, LA. https://irma.nps.gov/Datastore/Reference/Profile/2255921 Carlson, J.E. 2018. Monitoring amphibians on Gulf Coast Network parks: supplemental information: close- out of the pilot phase and recommended modifications for final amphibian monitoring design. Gulf Coast Network, Lafayette, LA. https://irma.nps.gov/DataStore/Reference/Profile/2243804. Dixon, J.R. 2000.Amphibians and reptiles of Texas. Texas A&M University Press. College Station, TX. Dodd, C.K. 2013. Frogs of the United States and Canada, Volume 1. The Johns Hopkins University Press, Baltimore, MD. Dundee, H.A., and D. A. Rossman. 1989. The amphibians and reptiles of Louisiana. Louisiana State University Press, Baton Rouge, LA. Duran, C.M. 2004. An inventory of reptiles and amphibians of Padre Island National Seashore, San Antonio Missions National Historic Park, and Palo Alto National Historic Site. Final Report (IFR) to the NPS Gulf Coast I&M Network.

Image SM-1. Map of vegetation management zones for the three amphibian monitoring study sites at San Antonio Missions NHP, with locations of amphibian monitoring clusters overlaid. Larger map (right) shows study site locations in the park. 7

Photo SM-2. Coverboards at HP cluster 3 at two times of year, October (left) and February (right). In this site as for the other two sites, ground cover changes drastically over the seasons, from sparse during late spring, summer and early fall, to dense during the winter leaf-off period. This area is within the park’s riparian ecosystem management zone.

Photo SM-3. Coverboards at SJ cluster 1, in June 2019. This area is within the park’s riparian ecosystem management zone. 8

Photo SM-4. Coverboards (buried in leaves) at WS cluster 4, in October 2018. This area of the park is classified as upland vegetation management zone, but it has riparian elements like the other two sites. Sampling for this event was assisted by Greg Mitchell, Natural Resources Program Manager for the park.

Photo SM-5. The continuous data loggers for temperature and relative humidity in their protective covers for two sites in July 2019.

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Photo SM-6. Gulf Coast toad (Incilius nebulifer) found under a coverboard at San Antonio Missions NHP.

Photo SM-7. Western narrow-mouthed toad (Gastrophyrne olivacea) found under a coverboard at San Antonio Missions NHP.

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Photo SM-8. Rio Grande Chirping frog (Eleutherodactylus cystignathoides) found under a coverboard at San Antonio Missions NHP.

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