|Scientific Name:||Varronia rupicola (Urb.) Britton|
Cordia rupicola Urb.
Varronia bahamensis Britton & P. Wilson
|Taxonomic Source(s):||Miller, J.S. and Gottschaling. 2007. Generic classification in the Cordiaceae (Boraginales): resurrection of the genus Varronia P. Br. Taxon 56(1): 163-169.|
|Taxonomic Notes:||Molecular, morphological and palynological data all support the recognition of Varronia as a distinct genus from Cordia (Miller and Gottschaling 2007). Hence this species has been transferred from Cordia to Varronia.|
|Red List Category & Criteria:||Endangered B2ab(ii,iii,v) ver 3.1|
|Assessor(s):||Hamilton, M.A., Sanchez, M. & Bárrios, S.|
|Contributor(s):||Monsegur, O., Sustache, J.A., Heller, T.M., Wenger, L., Clubbe, C.P., Pollard, B.J., Smith-Abbott, J., Woodfield-Pascoe, N.K., Walker, R., Corcoran, M.R. & Gavilan, J.|
This species was previously assessed as Critically Endangered (Clubbe et al. 2003). Research into its biogeography, systematic placement and conservation genetics by Hamilton (2016) has resulted in much improved knowledge and new data for the species. This species was found to be more widespread than previously thought but is still experiencing serious threats; therefore, it's status has been changed here to Endangered. The species has a small area of occupancy (AOO) well under 500 km2, is known from five locations and there is continuing decline due the many threats.
|Previously published Red List assessments:|
|Range Description:||Varronia rupicola is an endemic plant species found in the British Virgin Islands (BVI) and Puerto Rico. In BVI the species only occurs on the island of Anegada. In Puerto Rico the species is present on the main island of Puerto Rico and on the island of Vieques. The extent of occurrence (EOO) and the area of occupancy (AOO) were estimated to be 6,164 km2 and 116 km2, respectively, based on a 2x2 km2 cell size (Bachman et al. 2011). Genetic work by Hamilton (2016) detected five subpopulations across the three islands with extant individuals. The subpopulations found had lower than expected levels of heterozygosity as well as significant genetic differentiation and inbreeding. Analysis of ex situ collections and historic vouchers revealed a loss of genetic diversity when compared to extant individuals. Comparison of historical records (many not available during previous assessment) and modern observations showed a decrease in the species AOO. The species occurs in an extremely limited area of intact habitat that was found to be less than 90 km2 overlying specific substrates that only cover less than 200 km2 across the three islands. As the species habitat is discontinuous and population genetic data suggests five differentiated subpopulations, we have determined that the species is severely fragmented. The number of locations was calculated to be five and are as follows. On Anegada the main threats are invasive alien species, sea level rise and development. Because invasive alien species and sea level rise would impact both detected subpopulations equally on the island, Anegada is considered as one location. Vieques is considered a single location as less than 3 km2 of the species habitat remains and the main threats are human disturbance due to maintenance of roads and clearance of unexploded ordinance. The island of Puerto Rico represents three locations due to the different threats faced within and outside protected areas. The main threats identified are development, arson and human disturbance due to maintenance of roads and utilities and recreational activities.|
Native:Puerto Rico; Virgin Islands, British
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||Population estimated to be between 500 and 1,000 individuals (Hamilton et al. 2015).|
|Current Population Trend:||Decreasing|
|Habitat and Ecology:||This species is a medium to large shrub or small tree that grows in dry forest habitats with shallow soils overlying limestone. On the island of Anegada, the species is also found growing on sandy substrates overlying limestone, sometimes in very close proximity to the sea.|
|Continuing decline in area, extent and/or quality of habitat:||Yes|
|Use and Trade:||There are no current uses for this species.|
|Major Threat(s):||Across its native range, this species is subjected to several threats. By far the greatest threat to the species is habitat loss caused by development for housing and infrastructure. Degradation and fragmentation of the species habitat are on-going and are also a major concern. The species is also threatened by human-induced fire, particularly on Puerto Rico, and natural disasters, particularly hurricanes and tsunamis, due to the limited numbers of individuals and locations. Insect pests, especially exotics, are also a threat to the species across its range. Malumphy et al. (2015) reported two pests attacking this species. On the island of Anegada, feral livestock are a major threat to the species as the uncontrolled grazing is degrading and altering the island's vegetation. In the future, climate change may impact the species through more severe droughts, higher wind speeds in tropical hurricanes and sea level rise.|
|Conservation Actions:||The species occurs within established protected areas on the islands of Puerto Rico and Vieques and proposed protected areas on Anegada that together contain 32% of its remaining intact preferred habitat (Hamilton 2016). The species is held in several local and international ex situ collections. Unfortunately, Hamilton (2016) found that these existing and proposed protected areas and existing ex situ collections do not adequately protect and represent the extant wild genetic diversity. The Vieques National Wildlife Refuge on the island of Vieques contains the single location known to support the six extant wild individuals of the species. An ex situ collection of living plants derived from the wild individuals has been established at the refuge nursery. No other ex situ collections are known from Vieques source material; therefore, further collections should be established, especially of seed in long-term storage. On the island of Puerto Rico, Hamilton (2016) found that 59% of the extant plants are under protection in the Guánica State Forest; however, all of the individuals are from one of the two subpopulations detected. Two ex situ collections of living plants derived from limited numbers of wild individuals from one subpopulation (Guánica) have been established at the Guánica State Forest and the Cabo Rojo National Wildlife Refuge. There are ex situ living plants at Kew's Tropical Nursery, UK also from the Guánica subpopulation. Further collecting needs to be undertaken to secure seed from both Puerto Rico subpopulations in long-term storage. The two subpopulations detected by Hamilton (2016) on Anegada would have 51% (western subpopulation) and 13% (eastern subpopulation) of the individuals observed under protection if the proposed protected areas (Gardner et al. 2008) are declared. An ex situ collection of living plants derived from limited numbers of wild individuals from both subpopulations detected has been established at the J.R. O'Neal Botanic Gardens on Tortola, BVI. There are ex situ seed collections in Kew's Millennium Seed Bank, UK (T.M. Heller pers. comm. 2016), living plants at Kew's Tropical Nursery, UK and living plants at the Fairchild Tropical Botanical Garden, Miami, Florida, USA. All three were derived from the western subpopulation. Further collecting needs to be undertaken to secure seed from both Anegada subpopulations in long-term storage.|
Bachman, S., Moat, J., Hill, A.W., de la Torre, J. and Scott, B. 2011. Supporting Red List threat assessments with GeoCAT: geospatial conservation assessment tool. In: V. Smith and L. Penev (eds) e-Infrastructures for data publishing in biodiversity science. Zookeys 150: 117–126.
Clubbe, C., Pollard, B., Smith-Abbott, J., Walker, R. and Woodfield, N. 2003. Varronia rupicola. The IUCN Red List of Threatened Species 2003: e.T43896A91321755. DOI: /10.2305/IUCN.UK.2003.RLTS.T43896A91321755.en.
Gardner, L., Smith-Abbott, J. and Woodfield-Pascoe, N. 2008. British Virgin Islands Protected Areas System Plan 2007-2017. BVI National Parks Trust, Roadtown, Tortola, BVI.
Hamilton, M.A. 2016. Puerto Rican Bank (British Virgin Islands & Puerto Rico) September-October 2016 fieldwork report. Overseas Fieldwork Committee registration number 559-12. Royal Botanic Gardens, Kew, Richmond, Surrey, U.K.
Hamilton, M.A., Monsegur, O., Sustache, J., Velez, J., Pascoe, N.W., Harrigan, N., Linsky, J., Corcoran, M., Barrios, S., Heller, T., Clubbe, C., Bradley, K. and Sanchez, M. 2015. Boraginaceae Varronia rupicola - conserving a threatened species endemic to the Caribbean. In: M. Pienkowski and C. Wensink (eds), Sustaining Partnerships: a conference on conservation and sustainability in UK Overseas Territories, Crown Dependencies and other small island communities, Gibraltar 11th to 16th July 2015, pp. 105–107. UK Overseas Territories Conservation Forum, www.ukotcf.org.
IUCN. 2018. The IUCN Red List of Threatened Species. Version 2018-1. Available at: www.iucnredlist.org. (Accessed: 28 June 2018).
Miller, J.S. and Gottschaling. 2007. Generic classification in the Cordiaceae (Boraginales): resurrection of the genus Varronia P. Br. Taxon 56(1): 163-169.
|Citation:||Hamilton, M.A., Sanchez, M. & Bárrios, S. 2018. Varronia rupicola. The IUCN Red List of Threatened Species 2018: e.T43896A125645936.Downloaded on 25 September 2018.|
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