Cooperative Agreement F18AC00122: Inventory and Monitoring for Listed Plants and Pilot Study for the Restoration of Varronia rupicola at the Vieques National Wildlife Refuge Final Performance Report May, 2019 Erick N. Bermúdez-Carambot Wildlife Biologist CALLE FLAMBOYÁN 138 • VIEQUES, PR 00765 • 787.741.8850 • 787 741-2844 (fax) [email protected] • www.vcht.org Pilot study for the restoration of Varronia rupicola at the Vieques Wildlife Refuge and monitoring of other listed plant species present in Vieques Background The island of Vieques is small by US continental standards, yet, it exhibits species diversity and endemism. There are several and diverse habitats, which include some of the best examples of native flora in the archipelago of Puerto Rico; endemic, threatened and endangered plant species. The Vieques National Wildlife Refuge (VNWR) occupies approximately half of the island and borders two other protected areas. On the Eastern tract of the VNWR it borders the Vieques Bioluminescent Bay Natural Reserve (VBBNR), under the jurisdiction of the Puerto Rico Department of Natural and Environmental Resources (DNER) and co-managed by this Agnecy and the Vieques Conservation and Historical Trust (VCHT). On the Western tract it borders Cerro El Buey Nature Reserve, managed by Para La Naturaleza which is the land management branch of the Puerto Rico Conservation Trust (PRCT). Several listed species populations or individuals are believed to be found within these protected areas in Vieques: Varronia rupicola, Stahlia monosperma, Goetzea elegans, Eugenia woodburyana, Calyptranthes thomasiana and Scaevola plumieri. The Endangered Species Act (ESA) calls for re-establishing populations of ESA Spp. within protected areas, such as the Vieques NWR and the DNER Vieques Bioluminescent Bay Reserve. Portions of these conservation areas are Designated Critical habitat for the species Varronia rupicola. Project objectives This project constitutes a joint effort between the VNWR and the VCHT to re- establish populations of Varronia rupicola and to survey and map ESA and 2 Commonwealth listed plants species within protected areas of Vieques through the development of two components: 1) A pilot study to re-introduce Varronia rupicola into areas identified as Designated Critical Habitat for this species, as well as to evaluate the efficacy of these efforts. This includes propagating material from seeds and rescuing seedlings vulnerable to extirpation; and propagation of native material for habitat enhancement and restoration of degraded areas. 2) A survey of the Vieques National Wildlife Refuge (VNWR) and adjacent conservation lands to inventory and monitor target species - - in previously identified areas, as well as search for and map areas where these species may be present but have yet to be identified. Also, identify suitable areas presenting the best characteristics for the possibility to re-establish populations of ESA and commonwealth listed plants species within protected areas. Varronia rupicola recuperation component Of all the target plant species for this project, Varronia rupicola is the most at risk and has the lowest number of individuals found on the VNWR. Throughout all its range in Puerto Rico and the British Virgin Islands, Varronia rupicola is threatened by habitat degradation. About half of the known populations and the species’ suitable habitat lies within privately owned land which is being modified, or is proposed to be modified, for urban development. Habitat modification by urban development has promoted the invasion of the species habitat by nonnative plant species (e.g. grasses) that are typically fire-adapted and therefore, increase the chances of fires by providing a higher fuel load in the ecosystem. Overall, nonnative plants and fires may result in extirpation of populations of V. rupicola by killing individuals, limiting natural recruitment, or permanently modifying habitat and conditions necessary for the 3 species' establishment. Furthermore, due to the species' limited numbers and distribution, hurricanes may extirpate entire populations, and, in the case of a highly fragmented habitat, hurricanes may further promote the invasion of forest gaps by nonnative plant species rather than native pioneers. Similarly, severe droughts resulting from climate change may compromise the survival of seedlings and diminish natural recruitment within wild populations. Varronia rupicola, also known as Puerto Rican Manjack, is an endangered species of plant endemic to Puerto Rico, Anegada, and the British Virgin Islands. In Puerto Rico, this species is commonly found at low elevations at the edge of dry tropical shrub lands or hillside thickets in Puerto Rico. This kind of habitat is usually exposed to human activities, such as road or trail maintenance, urban development or other activities that cause habitat damage or fragmentation and which threatens the species. In Vieques we have a small natural population of the species in the Puerto Ferro Peninsula in the Vieques National Wildlife Refuge (Eastern Tract). In 2015 only 6 individuals were found in the area. Currently, the Vieques population consists of 40 individuals, an increase in population due to the conservation efforts that are being conducted since 2015. The current population is distributed in two groups: 18 individuals in the in-situ or wild population and 22 in the VNWR greenhouse. The current wild or in-situ population in the Puerto Ferro Peninsula consists of a total of 18 individuals: 3 original individuals, 1 juvenile from November 2015, 11 juveniles from 2018 and 3 seedlings from 2019. Distribution of the individuals in the in-situ population can be appreciated in Graph #1 and Picture #1. As part of the monitoring and care of the in-situ population, some site maintenance was done. The invasive species in the area were removed and other vegetation in the area was pruned. Termites and fire ants were observed at the base of 4 adults #1, #3 and #5 (Photo #2). Botanist Omar Monsegur (from the Caribbean Ecological Services Field Office) and Dr. Martin A. Hamilton (Kew Gardens Conservation Science Research Leader) told me that similar situations have been observed in the Guánica State Forest. Samples were collected for further identification of the species and the area has been monitored to report any effect of the presence of the insects at the base of the plants. A mix of neem oil, soap and water was sprayed in the area to try to control the ants and termites, but it hasn’t been effective; ant and termites continue present after the applications. Diatomaceous Earth was also applied in the area to control the termites and ants; this natural alternative to control crawling insects has been successful in eliminating these insects. The individuals #1 and #5 have lost around 60% of the foliage from the stem that was infected with ants and termites, but the other branches are producing new leaves and the plants seem to be recovering. Termites damaged a big part of the plant cortex. The seedlings are under continuous monitoring and if they seem to start getting weak or lose leaves, they will be relocated to the VNWR provisional greenhouse as happened with the individual #6B which now looks healthy and is growing in a 2-gallon pot. Temperature and humidity have been monitored in the wild population with a sensor provided by Botanist Monsegur since 2015. But in September 2017 it was damaged by Hurricane María. A new one was installed in the area on May 2018 (Photo #3). The old one was removed and when connected to a computer; we found that it stopped logging data on September 20, 2017, clearly affected by the hurricane. The unit was sent back to Botanist Monsegur at the Ecological Services Field Office in Cabo Rojo. The location of the in-situ population is exposed to the wind and salt spray in the peninsula. As part of the conservation program, reforestation in the area was conducted on June 2018 in collaboration with the YCC from the VNWR and Manta Raya kids from the Vieques Conservation and Historical Trust. A total of 18 sea grape 5 individuals (Cocoloba uvifera) and 10 “corcho bobo” (Pisonia albida) were planted to make a wind barrier in front of the Varronia population and all individuals are doing well at the moment. The population at the greenhouse consists of a total of 22 plants: 15 individuals collected between 2015 and 2018 from the in-situ population due to low probabilities of surviving and 7 individuals germinated at the greenhouse. All the plants are in good conditions and most of the individuals are producing fruits (Photo #4). As part of the propagating process I have collected seeds from both the greenhouse and in-situ populations, which are scarified and stored in a paper envelope identified with the date collected, plant and population of origin (Photo #5). All seeds produced in the greenhouse have been collected and only 20% of the seeds produced in the in-situ population have been collected. I have a total of 2,038 seeds from the greenhouse population; 80% of the seeds (1,374 seeds) were sent to Omar Monsegur to preserve at the University of Puerto Rico-Mayagüez for future germination in Vieques. Meanwhile the other 20% of the seeds have been kept in Vieques for germination attempts under different processes (Table #1). During the period of this project no seeds were collected from the wild population due to the low numbers of seed produced. Using as reference the Report on the status of Cordia rupicola Urban Including a Germination and Cultivation Protocol (March 2010) I treated 10 seeds in different ways and planted them. Only 5 seeds were able to germinate at the greenhouse, but they didn’t tolerate the changes during and after the hurricane. The plants were placed in the maintenance building at the VNWR for the hurricane. The greenhouse was lost during the hurricane, so we made a temporary structure to place endangered plants while a new greenhouse is built.