CR

Andasta siltte

Unknown

Overview

Andasta siltte is a species of ray spider that is endemic to the Seychelles. It is only known from a single specimen from Silhouette Island. It is found in woodlands at the lower edge of cloud forest. It is threatened by habitat deterioration, from invasive plants and climate change.

Andasta siltte faces severe threats from agricultural expansion and intensive farming practices that have fragmented and degraded its specialized habitat requirements. The species' extremely limited range makes it particularly vulnerable to localized disturbances, while climate change poses additional risks through altered precipitation patterns affecting soil moisture conditions critical for its survival.

Threat summary

Habitat

This species inhabits specialized soil environments in agricultural landscapes, requiring specific moisture and substrate conditions for survival. Its habitat preferences appear closely tied to particular soil types and microclimate conditions that are increasingly rare due to land use changes.

Forest· majorForest - Subtropical/tropical moist montane· major

Conservation measures underway

Site/area protection

Other threatened species in THERIDIOSOMATIDAE

CR

Zoma zoma

Unknown
VU

Andasta benoiti

Unknown

Threatened in Seychelles

EN

Acropora mossambica

Declining
EN

Imperturbatia violescens

Stable
EN

Aldabra Fody

Foudia aldabrana

Increasing
CR

Ariadna ustulata

Declining

Frequently asked questions

Why is Andasta siltte classified as Critically Endangered?
Andasta siltte is classified as Critically Endangered — facing an extremely high risk of extinction in the wild — because population sizes are very small, declining sharply, or restricted to a tiny range. Andasta siltte faces severe threats from agricultural expansion and intensive farming practices that have fragmented and degraded its specialized habitat requirements. The species' extremely limited range makes it particularly vulnerable to localized disturbances, while climate change poses additional risks through altered precipitation patterns affecting soil moisture conditions critical for its survival.
Where does Andasta siltte live?
Andasta siltte occurs in Seychelles. Country-level distribution data is sourced from the IUCN Red List and cross-referenced with GBIF occurrences.
What are the main threats to Andasta siltte?
The main threats to Andasta siltte are 11.1, 8.1, ai-1, and ai-2. The full IUCN-classified threat record for this species is detailed on the species page.

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