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Boettgeria crispa 

Scope: Global & Europe
Language: English
Status_ne_offStatus_dd_offStatus_lc_offStatus_nt_offStatus_vu_offStatus_en_onStatus_cr_offStatus_ew_offStatus_ex_off

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Mollusca Gastropoda Stylommatophora Clausiliidae

Scientific Name: Boettgeria crispa (R.T. Lowe, 1831)
Synonym(s):
Clausilia crispa R.T. Lowe, 1831
Clausilia decolorata Wollaston, 1878
Taxonomic Source(s): Bank, R.A. 2013. Fauna Europaea: Mollusca: Gastropoda. Available at: http://www.faunaeur.org.

Assessment Information [top]

Red List Category & Criteria: Endangered B1ab(ii,iii,iv,v)+2ab(ii,iii,iv,v) ver 3.1
Year Published: 2017
Date Assessed: 2016-12-02
Assessor(s): Teixeira, D., Cameron, R., Groh, K. & Seddon, M.B.
Reviewer(s): Neubert, E. & Allen, D.J.
Justification:

This species is endemic to the Madeiran Islands, where it is found between 300 to 1,000 m elevation. It is more frequently found in the northern areas on the laurisilva zone. It is present in the intermediate zone with the mature trees and cliffs, and is not found higher on the ridges. The extent of occurrence (EOO) is estimated at 212 km2 and the area of occupancy (AOO) at 124 km2.

Surveys for this species have reported a general decline since 2006. Surveys between 2006 and 2014 were carried out in numerous sites originally visited in the 1980s to 1999. In comparison, the number of populated sites has declined by at least 30% and the abundance of individuals at sites has declined significantly more (60 to 80%). The main threats that may explain these decline are the loss of large trees due to storm damages or fires, microclimate changes towards more windy, less rainy conditions; and wildfires.

Since the decline over the last ten years is of at least 30% in the area of occupancy (AOO) and 60% in the numbers of mature individuals, the species is assessed as Endangered (EN B1ab(ii,iii,iv,v)+2ab(ii,iii,iv,v)). A monitoring programme for this species is going to be carried out in the next few years, and conservation actions such as habitat management are strongly suggested.

Previously published Red List assessments:

Geographic Range [top]

Range Description:

This species is endemic to Madeira Island, where it is found from 300 to 1,000 m elevation. It is more frequently found in the northern areas on the laurisilva zone. It is present in the intermediate zone with mature trees and cliffs, and is not found higher on the ridges.

Surveys for this species have reported a general decline since 2006. Surveys between 2006 and 2014 were carried out in numerous sites originally visited in the 1980s to 1999. In comparison, the number of populated sites has declined by at least 30% and the abundance of individuals at sites has declined significantly more (60 to 80%) (K. Groh et al. pers. comm. 2016). In general, it can reliably be found in only four sites during visits (D. Teixeira pers. comm. 2016). The surveys have been conducted under suitable conditions and hence this decline is not considered to be a sampling artifact.

Countries occurrence:
Native:
Portugal (Madeira)
Additional data:
Estimated area of occupancy (AOO) - km2:124Continuing decline in area of occupancy (AOO):Yes
Estimated extent of occurrence (EOO) - km2:212
Continuing decline in extent of occurrence (EOO):Unknown
Number of Locations:4-15
Lower elevation limit (metres):300
Upper elevation limit (metres):1000
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:The population is believed to be declining, but it requires skilled surveyors rather than general surveyors to locate the species.

Declines for the populations of this species have been observed in the last ten years. Surveys between 2006 and 2014 have been carried out in areas originally visited in the 1980s to 1999. In comparison, the number of populated sites has declined by at least 30% and the abundance of individuals at sites has declined significantly more (60 to 80%) (K. Groh et al. pers. comm. 2016). In general, it can reliably be found in only four sites during visits (D. Teixeira pers. comm. 2016). The surveys have been conducted under suitable conditions and hence this decline is not considered to be a sampling artifact.
Current Population Trend:Decreasing
Additional data:
Continuing decline of mature individuals:Yes
Extreme fluctuations:NoPopulation severely fragmented:Yes
Continuing decline in subpopulations:Yes
All individuals in one subpopulation:No

Habitat and Ecology [top]

Habitat and Ecology:

The species is usually found on trunks of large trees within Laurisilva forest, where it is found in crevices of the bark, or on leaf-litter at base of trunks. It is sometimes found on the rock-crags, where it lives amongst leaf litter on ledges.

Declines in population abundance have been observed, and there has been a decline in the quality of the habitat as a result of forest fires. There has also been an increase in the frequency of windy days, and a decrease in the number of rainy days.

Systems:Terrestrial
Continuing decline in area, extent and/or quality of habitat:Yes
Generation Length (years):1-2

Use and Trade [top]

Use and Trade: This species is not used.

Threats [top]

Major Threat(s):

There are several major threats. The loss of large trees due to storm damage or fire remain as ongoing threats. Additional threats are the increased frequency of windy days and a decrease in the number of rainy days, which can change the microclimate and macrohabitat of the area. These climate changes are particularly affecting the north of the island, which is the area where the species has been historically more abundant.

Forest fires have impacted 30% of the occupied habitats in the last ten years (D. Teixeira pers. comm. 2016) and remain as a constant threat to the population, especially on the south side of the island. The four sites where the least impact has been seen are in the upper parts of the Laurisilva or sites that are more sheltered. The more impacted sites are those at intermediate elevations.

Conservation Actions [top]

Conservation Actions:

Habitat management in the Laurisilva zone is required to ensure the regeneration of large trees, as well as management of the woodland to retain large trees and other shaded rocky habitats that could be suitable for the species. Nearly 80% of the sites lie in a protected area (either Natura 2000 or Madeira Nature Park). There will be a monitoring programme for this species as part of the Natura 2000 designation.


Citation: Teixeira, D., Cameron, R., Groh, K. & Seddon, M.B. 2017. Boettgeria crispa. The IUCN Red List of Threatened Species 2017: e.T40057A107474950. . Downloaded on 20 August 2018.
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