Discula Tectiformis

The IUCN Red List of Threatened Species™ ISSN 2307-8235 (online) IUCN 2008: T6729A12801643

Discula tectiformis

Assessment by: Seddon, M.B.

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Citation: Seddon, M.B. 2013. Discula tectiformis. The IUCN Red List of Threatened Species 2013: e.T6729A12801643. http://dx.doi.org/10.2305/IUCN.UK.2011-1.RLTS.T6729A12801643.en

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THE IUCN RED LIST OF THREATENED SPECIES™ Taxonomy

Kingdom Phylum Class Order Family

Animalia Mollusca Gastropoda Stylommatophora Hygromiidae

Taxon Name: Discula tectiformis (Sowerby, 1824) Assessment Information

Red List Category & Criteria: Endangered B1ab(iii) ver 3.1

Year Published: 2013

Date Assessed: September 30, 2010

Justification: This species has a total extent of occurrence of 42 km2 with the four isolated sub-populations, three on a small hillslope area at the eastern part of the island. The habitat has been subject to changing land- use practice, and declined in quality over the last thirty years. The main range remains vulnerable to rodent predation, fires and other land management changes. It has been assessed as Endangered (EN) B1a b(iii).l

Previously Published Red List Assessments 1996 – Vulnerable (VU)

1994 – Rare (R)

Geographic Range

Range Description: This species is endemic to Porto Santo. There are records from the mainland where the species is now largely restricted to the east end of the island, but fossils show it was formerly widespread (Cameron et al. 2006). This species has a total area of occupancy of 16 km2 with the three isolated sub-populations, on two different hillslope areas at the eastern part of the island, and another at west end of the mainland opposite Ilheu de Baixo.

Country Occurrence: Native: Portugal (Madeira)

© The IUCN Red List of Threatened Species: Discula tectiformis – published in 2013. 2 http://dx.doi.org/10.2305/IUCN.UK.2011-1.RLTS.T6729A12801643.en Population There is no recent population trend data for this species. It is known to be impacted by rodent predation. Current Population Trend: Unknown

Habitat and Ecology (see Appendix for additional information) This species occurs in grassland with herbs, on coastal cliffs, rocky slopes and summits. The habitat has been subject to changing land-use practice, and declined in quality over the last thirty years. The site behind the harbour and at the west end of the island are the most vulnerable populations.

Systems: Terrestrial

Use and Trade This species is not used.

Threats (see Appendix for additional information) These small populations are vulnerable to rodent predation, fires and other habitat loss from tourist developments (hotels, recreational areas, roads).

Conservation Actions (see Appendix for additional information) None of the range falls within a designated protected area. Conservation actions include habitat monitoring for indication of population trends, as well as population monitoring to establish impact of the predation on the species. Credits

Assessor(s): Seddon, M.B.

Reviewer(s): Cameron, R., Groh, K. & Cuttelod, A.

© The IUCN Red List of Threatened Species: Discula tectiformis – published in 2013. 3 http://dx.doi.org/10.2305/IUCN.UK.2011-1.RLTS.T6729A12801643.en Bibliography Cameron, R.A.D.C., Cook, L.M., Goodfriend, G.A. and Seddon, M.B. 2006. Fossil Landsnail faunas from Porto Santo, Madeiran Archipelago; change and stasis in Pleistocene to recent times. Malacologia 49(1): 25-59.

IUCN. 2011. IUCN Red List of Threatened Species (ver. 2011.1). Available at: http://www.iucnredlist.org. (Accessed: 16 June 2011).

Citation Seddon, M.B. 2013. Discula tectiformis. The IUCN Red List of Threatened Species 2013: e.T6729A12801643. http://dx.doi.org/10.2305/IUCN.UK.2011-1.RLTS.T6729A12801643.en

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Habitats (http://www.iucnredlist.org/technical-documents/classification-schemes)

Major Season Suitability Habitat Importance? 4. Grassland -> 4.4. Grassland - Temperate - Suitable Yes

0. Root -> 6. Rocky areas (eg. inland cliffs, mountain peaks) - Suitable No

Threats (http://www.iucnredlist.org/technical-documents/classification-schemes)

Threat Timing Scope Severity Impact Score 1. Residential & commercial development -> 1.3. Ongoing Majority (50- Rapid declines Medium Tourism & recreation areas 90%) impact: 7 Stresses: 1. Ecosystem stresses -> 1.1. Ecosystem conversion 1. Ecosystem stresses -> 1.2. Ecosystem degradation 2. Species Stresses -> 2.1. Species mortality 2. Species Stresses -> 2.2. Species disturbance 6. Human intrusions & disturbance -> 6.1. Ongoing Majority (50- Slow, significant Medium Recreational activities 90%) declines impact: 6 Stresses: 1. Ecosystem stresses -> 1.2. Ecosystem degradation 2. Species Stresses -> 2.2. Species disturbance 7. Natural system modifications -> 7.1. Fire & fire Ongoing Minority (50%) Rapid declines Medium suppression -> 7.1.1. Increase in fire impact: 6 frequency/intensity Stresses: 1. Ecosystem stresses -> 1.1. Ecosystem conversion 1. Ecosystem stresses -> 1.2. Ecosystem degradation 2. Species Stresses -> 2.1. Species mortality 2. Species Stresses -> 2.2. Species disturbance 8. Invasive & other problematic species & genes -> Ongoing Majority (50- Slow, significant Medium 8.1. Invasive non-native/alien species -> 8.1.2. 90%) declines impact: 6 Named species Stresses: 2. Species Stresses -> 2.1. Species mortality 2. Species Stresses -> 2.2. Species disturbance 2. Species Stresses -> 2.3. Indirect species effects -> 2.3.8. Other

Conservation Actions in Place (http://www.iucnredlist.org/technical-documents/classification-schemes)

Conservation Actions in Place In-Place Land/Water Protection and Management

Occur in at least one PA: No

© The IUCN Red List of Threatened Species: Discula tectiformis – published in 2013. 5 http://dx.doi.org/10.2305/IUCN.UK.2011-1.RLTS.T6729A12801643.en Research Needed (http://www.iucnredlist.org/technical-documents/classification-schemes)

Research Needed 3. Monitoring -> 3.1. Population trends

3. Monitoring -> 3.4. Habitat trends

Additional Data Fields

Distribution Estimated extent of occurrence (EOO) (km²): 42

Number of Locations: 3

Population Population severely fragmented: No

Habitats and Ecology Continuing decline in area, extent and/or quality of habitat: Yes

© The IUCN Red List of Threatened Species: Discula tectiformis – published in 2013. 6 http://dx.doi.org/10.2305/IUCN.UK.2011-1.RLTS.T6729A12801643.en The IUCN Red List of Threatened Species™ ISSN 2307-8235 (online) IUCN 2008: T6729A12801643

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