Supplementary Materials for Trip Report for Vegetation Monitoring In

While summarizing field trip data, 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 results will be in future trend reports, which are written after three rounds of data collection (i.e., report 1 summarizes 2019, 2022 and 2025 trips). The Supplementary Materials document for vegetation monitoring at Palo Alto Battlefield National Historical Park (NHP) in 2019 contains (1) a table of plant species and the number of plots where they were found; (2) a table of Cameron County species that are considered of conservation need by the state of Texas; (3) updates on invasive plant management and fire at the park; (4) several maps showing landscape features, such as soil maps, elevation and land use history; (5) useful references on park vegetation, land use history and other relevant characteristics of the park; and (6) select photos of fieldwork and species ID from 2019.

Table SM-1 lists all of the plant species found in vegetation plots during sampling in June 2019 and the number of plots where that species was found. Across the nine plots, the most species were recorded in Ba 5, at 55 species. This plot was unique in that it was predominantly Tamaulipan shrubland, but also had portions of mixed grassland that included native grasses, borrichia (Borrichia frutescens), honey mesquite (Prosopis glandulosa), cacti and Spartina spartinae. The second most species-rich plot, Ba 8, was also unique, in that it was along an old riverbed that holds water for prolonged periods. Its species list contains freshwater wetland plants that were not seen elsewhere, such as jointed and green flatsedges (Cyperus articulatus and C. virens), longtom (Paspalum denticulatum), spikerush (Eleocharis sp.), bigfoot waterclover (Marsilea macropoda), winged lythrum (Lythrum alatum) and brown’s savory (Clinopodium brownei). One of the lowest richness plots, Ba 6, was also unique among sampled plots. It was in an area of richer soil that once grew Sorghum as a crop, but eventually went fallow and became dominated by the invasive Kleberg bluestem (Dichanthium annulatum). The remaining six plots were all types of native prairie. The lowest richness was associated with dominance of Spartina spartinae or borrichia (i.e., Ba 4 or Ba 9), although those vegetation types could also have higher richness (i.e., Ba 1, Ba 2). Sites Ba 3 and Ba 7 were in the northern half of the park, were on a different soil type and tended to have more honey mesquite. The following resources were used for species ID: Gould (2000), Richardson and King (2011), Hatch et al. (1999), Jones (1982) and Correll and Johnston (1975). Latin names are from USDA plants as of March 2020 (USDA, NRCS 2020). The network did not and will not collect permanent herbarium vouchers during sampling. As a result, new records for the park would need to be vouchered separately, by park staff or in response to a specific request from park staff. 1

Table SM-1. List of plant species from 2019 vegetation monitoring. The ‘Total’ column is the number of plots where that species was detected at least once. The column ‘Not Listed on Park Inventory’ uses ‘Not Listed’ for species that were not on the published inventory by Lonard et al. (2004) and are not currently on NPspecies for the park, although all seven such species do have herbarium records for Cameron county. A dash in that column means the species is on the 2004 published inventory and on NPspecies for the park. Because this monitoring effort has just begun, the network recommends waiting until after the next sampling interval to add any new species to NPspecies. In the ‘Non-native’ column, ‘targeted’ means that the species is a priority for treatment by invasive species management teams. More information on non-native species is in section 3 of this document.

2 3 Non-native

4 5 Table SM-2 lists the species that are on the current Texas list of plant species of greatest conservation concern and are either present at the park or are recorded for Cameron County. None of these species have been recorded in the network’s vegetation monitoring plots, and if they were, the specific plot name would not be reported. More information on these species can be found in Table 8 of the integrated plant management plan for the park (Keyes and Perry 2010).

Table SM-2. List of park species of greatest conservation need, as listed by Texas Parks and Wildlife Department. Most of the species are only county records and seem unlikely to be in the park.

6 Invasive and Non-native Plants The most problematic invasive species at Palo Alto Battlefield NHP include several grass species and the Brazilian pepper tree (Schinus terebinthifolius). Brazilian pepper tree has been the focus of several invasive management efforts on the park. It occurs infrequently on the park’s main unit, but is very common on the Resaca de la Palma unit, 8 km away (see next section for more details). Within the main unit, Kleberg bluestem (Dichanthium annulatum) is the park’s most wide-spread invasive species; it was recorded in nearly all of the vegetation monitoring plots. There are large areas along the visitor walking trails and the recently-filled resaca and dams (southeast of Ba 5) that are dominated by that species. The other most problematic grass is guineagrass (Urochloa maxima), which performs well in both sun and shade and is becoming increasingly common on park lomas. It was present in three of the vegetation monitoring plots. Three more invasive grasses were each found in only one plot: buffelgrass (Pennisetum ciliare), silky bluestem (Dichanthium sericeum), and swollen fingergrass (Chloris barbata). Finally, perennial cupgrass (Eriochloa pseudoacrotricha) is a relatively new non-native grass from Australia that was seen in five plots and was fairly abundant in some areas. This species was on the 2004 park species list by Lonard et al., but it is still poorly documented in Texas. Table SM-3 below is our most complete list of possible and confirmed non-native species in the park (possible is based on county records). The integrated vegetation management plan (Keyes and Perry 2010) has a similar list that includes the herbicides approved for treating them.

Table SM-3. Possible and confirmed non-native species for the park. An asterisks indicates the species is targeted as a priority for management by invasive plant management teams. The species Capraria mexicana/biflora is included as non-native, but appears to be a recent natural range expansion from Mexico. Isocarpha oppositifolia is another species that primarily occurs in Mexico and is listed in USDA plants as non-native to the USA, but this species is not listed here because it has been collected in a few locations in southern Cameron county since 1931, and this appears to be within its natural range.

, C. barbata , swollen fingergrass

7 Invasive Plant Management Team Summary The Gulf Coast Invasive Plant Management Team (IPMT) has conducted invasive plant removals at Palo Alto Battlefield in 2017 and 2019. Information on these treatments has been provided courtesy of Dale McPherson, IPMT Liaison. In April 2017, an IPMT crew treated Brazilian pepper tree in five locations at Resaca de la Palma. In 2019, a crew treated plants in both Resaca de la Palma and on the main park area, and the map where they worked is included below. In Resaca de la Palma, they treated Brazilian pepper tree and also removed some individuals of native retama tree (Parkinsonia aculeata). In the main park unit, they targeted Kleberg bluestem and King Ranch bluestem, which can be difficult to tell apart. They almost certainly were treating only Kleberg bluestem, since King Ranch bluestem is not currently known to occur in the park. Rolando Garza also reported that there was an additional one-time treatment of Kleberg bluestem in the heavily invaded area near Ba 6 sometime within the past 10 years, but this treatment was not known to have a notable impact.

Figure SM-1. GPS tracklogs of IPMT crews at Palo Alto Battlefield during their 2019 field efforts on the park. The inset map is Resaca de la Palma, which they treated for Brazilian pepper tree. The larger map is the main park unit, where Kleberg bluestem was targeted. The map is courtesy of Dale McPherson.

Other Plant Management Efforts There are currently two other active plant management efforts at the park, although the network is not directly involved in either. These are (1) removal of honey mesquite from the prairie and (2) Spartina spartinae planting to restore the prairie. For both of these projects, efforts thus far have focused on areas within viewing distance of the visitor’s center and trails. Rolando Garza, the park’s chief of resource management, should be contacted for more information on the locations and timing of plant removals (beginning in the late 2000s) and Spartina spartinae planting (beginning in 2014). Fire Fire management at Palo Alto Battlefield NHP is served by the Fire staff at Big Bend National Park. There are currently efforts underway to draft a comprehensive fire management plan for the park. The current fire units are shown in Figure SM-2 below. Vegetation monitoring plots that were within one of the burn units (Ba 4, Ba 9, and Ba 1) had rebar stakes marking edge midpoints as well as corners, in the event that the fiberglass stakes were burned away. 9

Figure SM-2. The six burn units (colored polygons) at Palo Alto Battlefield NHP, as of 2019. Overlaid are locations of primary plots (black circles) for vegetation monitoring.

A variety of maps have been assembled below, with the expectation that the data they present could eventually help unravel differences among vegetation monitoring plots. Figure SM-3 shows bare earth elevation from 2013 lidar, and it also includes a table of elevation values for the plots, using the more recent 2018 lidar. Species richness values are included to show that there is no clear relationship between elevation and richness. Figure SM-4 is a rough land-use history map, adapted from Richard (1993) and other sources. The park is relatively young and is still growing, with official designation as a historic site in 1978, but not established as a park until 1992. The first section of the park (on the west side; much of the unshaded property on Figure SM-4) was conveyed in 1996, and there were large additions in 2000-2002, with more to come in the near future. Finally, Figure SM-5 is the soils map for the park (soil type descriptions in Williams et al. 1977).

Figure SM-3. Elevations across the park from 2013 lidar data. Elevation range is between 3.0 and 6.4 m, with the color ramp ranging from green in lowest elevations, to white in highest elevations. Vertical exaggeration is 20x to accentuate the slight elevational changes throughout the park. 11

Figure SM-4. Informal map of land use history on the park, based on Richard (1993), Haecker (1994), aerial imagery, property boundary GIS layers, and conversations with Rolando Garza. The colored polygons represent different land use regime that are associated with one or more property parcel and owner(s). Not all old property boundaries are shown. The vegetation monitoring plots are included as green circles. 12

Figure SM-5. Soils map for the park. Descriptions of the soil types can be found in the NRCS soils document for Cameron County (Williams et al. 1977). Areas labeled wet on the map (colored orange) do not necessarily reflect locations where standing water can currently be found.

Correll, D.S., M.C. Johnston. 1970. Manual of the vascular plants of Texas, first edition. Texas Research Foundation. Renner, TX. Farmer, M. 1992. A natural resource survey of Palo Alto National Battlefield. National Audubon Society, Brownsville, Texas. 24 pages. Gould, F.W. 2000. The grasses of Texas, first edition. Texas A&M University Press. College Station, TX.

Haecker, C.M. 1994. A thunder of cannon: Archeology of the Mexican-American War Battlefield of Palo Alto. Southwest Cultural Resources Center Professional Paper No. 52 http://npshistory.com/series/archeology/scrc/52/index.htm

Hatch, S.L., J.L. Schuster, D.L. Drawe. 1999. Grasses of the Texas Gulf prairies and marshes. Texas A&M University Press. College Station, TX. Jones, F.B. 1982. Flora of the Texas coastal bend. Mission Press. Corpus Christi, TX. Keyes, C. and T. Perry 2010. Palo Alto Battlefield National Historical Park Integrated Vegetation Management and Environmental Assessment. Completed through a cooperative agreement with the College of Forestry and Conservation, University of. Montana. http://files.cfc.umt.edu/cesu/NPS/UMT/2009/09Keyes_PAAL_veg%20plan_Fnl%20rpt.pdf. There is an updated draft available online at https://parkplanning.nps.gov/document.cfm?parkID=85&projectID=20670&documentID=56123 Lonard, R.I., F.W. Judd, J.H. Everitt and M.R. Davis. 2005. Remote sensing of Resaca wetlands in south Texas. 20th Biennial Workshop on Aerial photography, videography and high resolution digital imagery for Resource Assessment Oct 4-6 2005. Welasco, TX. Lonard, R.I., A.T. Richardson and N.L. Richard. 2004. The vascular flora of the Palo Alto National Battlefield Historic Site, Cameron County, Texas. Texas J. Sci 56(1): 15-34. Richardson, N.L., and K. King. 2011. Plants of deep South Texas: a field guide to the woody and flowering plants. Texas A&M University Press. College Station, TX. Richard, N. L., and A. T. Richardson. 1993. Biological inventory, natural history, and human impact of Palo Alto National Battlefield. Report to the National Park Service. Ramsey, E. 2006. Palo Alto Battlefield National Historic Site landscape classification and historic analysis. Unpublished report. Thornberry-Ehrlich, T. L. 2013. Palo Alto Battlefield National Historical Park: Geologic resources inventory report. Natural Resource Report NPS/NRSS/GRD/NRR—2013/710. National Park Service, Fort Collins, Colorado. USDA, NRCS. 2020. The PLANTS Database (http://plants.usda.gov, 16 April 2020). National Plant Data Team, Greensboro, NC 27401-4901 USA. Williams, D. Thompson, C.M., and J.L. Jacobs. 1977. Soil Survey of Cameron County, Texas. United States Department of Agriculture, Soil Conservation Service, in Cooperation with the Texas Agricultural

Experiment Station. https://www.nrcs.usda.gov/Internet/FSE_MANUSCRIPTS/texas/TX061/cameron.pdf

Photo SM-1. Crew member deconstructing vegetation monitoring plot Ba 7 after sampling on 6/26/2019.

Photo SM-2. Sampling frame (1 x 1 m) in Ba 7 that is dominated by Opuntia englemannii.

Photo SM-3. Sea lavender (Limonium carolinianum) in a historical river bed with salt-tolerant forbs.

Photo SM-4. Snout butterfly (Libytheana bachmanii) on lotebush (Ziziphus obtusifolia). 16

Photo SM-5. Features of two cupgrass species at the park. Perennial cupgrass Eriochloa pseudoacrtricha (left, above and below) is a non-native, whereas Louisiana cupgrass Eriochloa puncata is native. Both were found to be fairly common in certain areas of the park. Key ID features are the locations of hairs and the length of the awn in the upper photos. Best key available is from Hatch et al. 1999, and ID certainty is below 100%.

Photo SM-6. Four flowered trichloris (Trichloris pluriflora), a native grass that is found in a few areas of the park, such in the prairie along the road to the maintenance shed, northern side.

Photo SM-7. Guinea grass (Urochloa maxima) is a problematic invasive grass in the park. It grows in both shaded and unshaded areas. 18

Photo SM-8. Buffelgrass (Pennisetum ciliare) is an invasive grass that is not currently abundant on the park, but it is problematic in similar habitats in other parts of Texas.

Photo SM-9. Kleberg bluestem (Dichanthium annulatum) is most problematic invasive grass on the park. It is very common along the path from the visitor center.

Photo SM-10. Jewels of opar, Talinum paniculatum, in flower. This species can be found growing elsewhere in the USA but at Palo Alto Battlefield NHP, its leaves are much more succulent.