Abstract
ESR Endangered Species Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials ESR 34:339-347 (2017) - DOI: https://doi.org/10.3354/esr00860 Resurgence of Harrisia portoricensis (Cactaceae) on Desecheo Island after the removal of invasive vertebrates: management implications Cielo E. Figuerola-Hernández1,*, Kirsty Swinnerton1,2, Nick D. Holmes1, Omar A. Monsegur-Rivera3, José Luis Herrera-Giraldo1, Coral Wolf1,4, Chad Hanson1, Susan Silander5, Donald A. Croll4 1Island Conservation, Santa Cruz, California 95060, USA 2The Island Endemics Foundation, Boquerón 00622, Puerto Rico 3Caribbean Ecological Services Field Office, US Fish and Wildlife Service, Boquerón 00622, Puerto Rico 4Coastal Conservation Action Lab, University of California Santa Cruz, Santa Cruz, California 95060, USA 5Caribbean National Wildlife Refuge Complex, US Fish and Wildlife Service, Boquerón 00622, Puerto Rico *‑Corresponding author: cielo.figuerola@islandconservation.org ABSTRACT: Desecheo Island hosts a natural population of the higo chumbo cactus Harrisia portoricensis, listed as threatened under the US Endangered Species Act. The species was extirpated from mainland Puerto Rico and is restricted to the offshore islands of Mona, Monito and Desecheo. Herbivory by goats Capra hircus, rhesus macaques Macaca mulatta, and black rats Rattus rattus introduced to Desecheo Island have likely contributed to a population decline, with only a few individuals of higo chumbo reported in 2003. As part of a restoration program, goats have been eradicated, macaques are considered functionally extirpated, and actions to remove invasive rodents were completed in 2016 and confirmed as successful in 2017. Systematic monitoring was implemented between 2010 and 2013, including widespread searches for H. portoricensis, collecting data on population structure, number of individuals, height, number of branches and evidence of phenological events. After 4 yr of continuous monitoring, 72 individual plants were identified, which exhibited increased height and branching throughout the study years. No seedlings were observed and only a few juveniles recorded, suggesting a resurgence from suppressed adults with limited recruitment. Long-term monitoring is critical to understanding the population dynamics of this species on Desecheo Island. Efforts to safeguard this species on the island require completion of the invasive vertebrate removals and would benefit from a seed banking program and manual establishment of new populations. KEY WORDS: Invasive species · Eradication · Threatened species · Caribbean · Herbivory · Harrisia portoricensis · Cactaceae · Desecheo Island Full text in pdf format PreviousNextCite this article as: Figuerola-Hernández CE, Swinnerton K, Holmes ND, Monsegur-Rivera OA and others (2017) Resurgence of Harrisia portoricensis (Cactaceae) on Desecheo Island after the removal of invasive vertebrates: management implications. Endang Species Res 34:339-347. https://doi.org/10.3354/esr00860 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in ESR Vol. 34. Online publication date: November 23, 2017 Print ISSN: 1863-5407; Online ISSN: 1613-4796 Copyright © 2017 Inter-Research.
Highlights
Islands represent key areas for biodiversity conservation due to high levels of species endemism (Myers et al 2000)
The species has been extirpated from the main island of Puerto Rico, and in 1990 it was listed as threatened under the US Endangered Species Act, and considered Endangered under the 1997 IUCN Red List of Threatened Plants (Walter & Gillett 1998)
During our 4 yr study period (2010 to 2013), we found and measured a total of 72 individuals of Harrisia portoricensis (Table 1)
Summary
Islands represent key areas for biodiversity conservation due to high levels of species endemism (Myers et al 2000). Identified threats include natural catastrophes like hurricanes, habitat modification, low genetic variation, and herbivory by invasive species on Mona and Desecheo islands (USFWS 1996). Goats and macaques were observed feeding on the moist pulp after heavy rains, suggesting this was an important water source in the xeric climate on Desecheo (Evans 1989). In addition to these negative impacts, macaques may have had a positive role as seed dispersers of H. portoricensis (e.g. Sengupta et al 2014); this is unclear. Black rat consumption of H. portoricensis is unknown but should not be ruled out, given this species is highly omnivorous, and fruit, seeds, and vegetative matter from plants constitute a frequent component of their diet (Shiels et al 2013). Subsequent observations have suggested a dramatic decline, with 5 individuals recorded in 1999 (Santiago-Vélez 2000) and 9 in 2003 (Schwagerl pers. comm., cited in USFWS 2010), representing 0.9 to 1.6% of the observations made in 1994
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
