Isoplexis chalcantha 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Plantae Tracheophyta Magnoliopsida Scrophulariales Scrophulariaceae

Scientific Name: Isoplexis chalcantha Svent. & O'Shan.
Common Name(s):
Spanish Crestagallo de Doramas, Cresta de gallo

Assessment Information [top]

Red List Category & Criteria: Critically Endangered B1ab(i,ii,iii,iv)+2ab(i,ii,iii,iv) ver 3.1
Year Published: 2011
Date Assessed: 2011-02-15
Assessor(s): Marrero Rodríguez, Á, Naranjo Morales, M.
Reviewer(s): Peraza Zurita, M.D. & Bilz, M.
Contributor(s): Peraza Zurita, M.D.
Isoplexis chalcantha is classed as Critically Endangered due to its highly fragmented and restricted geographic range and negative trends reported for its distribution and population size. Its number of subpopulations has decreased to four. It presents very low extent of occurrence, 12 km², and area of occupancy, of 6 km². Predation and droughts affect the species and its habitat, limiting its expansion. It is as well affected by human impacts as collection for medicinal purposes, and agriculture.

Geographic Range [top]

Range Description:Isoplexis chalcantha is endemic to the island of Gran Canaria, the Canary Islands, Spain, where it grows between 400 and 900 m asl in the northern part of the island. It is found in four locations: Zumacal, Barranco la Virgen, Los Tilos and Los Propios. Two more locations were cited in the past but not recently found: Barranco Oscuro and Azuaje-Garañones, and one more reference has not been confirmed (Marrero and Naranjo 2004). It has been reported to present high fragmentation and regressive trends for its distribution (Gobierno de Canarias 2004).
Its extent of occurrence has been estimated in around 12 km² (Á. Marrero pers. comm. 2011) and its total area of occupancy has been estimated in 2 km² (Marrero and Naranjo 2004).
Countries occurrence:
Spain (Canary Is.)
Additional data:
Estimated area of occupancy (AOO) - km2:2
Number of Locations:4
Lower elevation limit (metres):400
Upper elevation limit (metres):900
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:Total population size is estimated in 392 individuals: 230 individuals in Zumacal, 62 in Barranco La Virgen, 99 in Los Tilos and one single individual at Los Propios. Its population size has been reported to suffer important fluctuations and decreases. Fruits are frequently aborted during drought events and the expansion of the species is limited by its restricted dispersion capacity and low germination and recruitment levels (Marrero and Naranjo 2004).

Current Population Trend:Decreasing
Additional data:
Number of mature individuals:392
Population severely fragmented:Yes

Habitat and Ecology [top]

Habitat and Ecology:It grows on slopes or understorey sites, on basaltic well-developed substrates, on the potential distribution range of laurel-leaved forests known as monteverde, within communities such as Myrico fayae-Ericetum arboreae and Visneo mocanerae-Arbutetum canariensis. It tends to grow in rupicolous communities Aeonietum virginii, but currently it is found in marginal and degraded areas of these communities (Marrero and Naranjo 2004, Commission of the European Communities 2009).
Common accompanying species are: Laurus novocanariensis, Sonchus congestus, Rubus bollei, Chamaecytisus proliferus, Semele gayae, Erica arborea, Dryopteris oligodonta, Brachypodium sylvaticum and Aeonium virgineum.

Use and Trade [top]

Use and Trade: It has medicinal applications as cardiotonic.

Threats [top]

Major Threat(s): Threats are taking and removal of flora and eutrophication (Commission of the European Communities 2009). Droughts are an important threat for the species (Marrero and Naranjo 2004). The predation by rabbits Oryctolagus cuniculus, mainly on seedlings and young individuals, along with periods of low precipitations also appears as an important population decreasing factor, as well as agriculture and occasional landslides.

Conservation Actions [top]

Conservation Actions: This species is listed on Annex II of the Habitat Directive and under Appendix I of the Convention on the Conservation of European Wildlife and Natural Habitats (Bern Convention). It is listed CR B1ab(i,ii,iii,iv)+2ab(i,ii,iii,iv) in the Spanish Red List (Moreno 2008). It is included as species "En peligro de extinción" in the national catalogue of threatened species, and in the regional catalogue of protected species.

It is found within the protected areas Reserva Natural Especial de Azuaje (SCI), Reserva Natural Integral del Barranco Oscuro (SCI), Reserva Natural Especial de Los Tilos de Moya and Parque Rural Doramas, as well as in the SCI Barranco de La Virgen.
Seeds of the species are stored in the germplasm bank Banco de Germoplasma del Jardín Botánico Viera y Clavijo and the E.T.S. de Ingenieros Agrónomos, Universidad de La Laguna. It has been included in a LIFE project and reinforcement plans have been locally developed.

Recuperation measures must be promoted, including the re-introduction of the species in the location currently extinct. Seeds from the different locations should be collected and stored.

Citation: Marrero Rodríguez, Á, Naranjo Morales, M. 2011. Isoplexis chalcantha. The IUCN Red List of Threatened Species 2011: e.T161967A5521614. . Downloaded on 22 January 2018.
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