MAIISG

Assessment Rationale:

Centromerus variegatus is endemic to Madeira Island, Portugal. This species has a restricted geographic range with a maximum estimate of extent of occurrence (EOO) and area of occupancy (AOO) of ca 700 km². However, Centromerus variegatus is assessed as Least Concern (LC), since the preferred habitat of the species, humid laurisilva forest, is not experiencing any decline in area or quality and the population is therefore assumed to be stable. A monitoring of population trends should be conducted to confirm species status.

Geographic Range:

Centromerus variegatus is known throughout the laurisilva forest that occupies about 20% of the island of Madeira (Portugal), mainly on the steep and humid northern slopes. Multiple collection sites are recorded for this species, mostly recent (Denis 1962, Wunderlich 1987, Crespo et al. 2014). It was possible to perform species distribution modelling to predict its potential range with confidence limits (Cardoso et al. 2017). The extent of occurrence (EOO) is estimated to be between 256-716 km² and the area of occupancy (AOO) to be between 232-716 km².

 

Population:

No population size estimates exist, but the population is assumed to be stable, since the preferred habitat of the species is not experiencing a decline in area and the invasive species present seem not to affect the spider population.

 

Habitat and Ecology

Centromerus variegatus is restricted to the humid laurisilva forest on the northern slopes of Madeira Island. This species is a sheet-web builder on the tree branches and under stones, feeding mainly on small insects.

Major Threat(s):

There are no known threats to this species.

Conservation Actions

No specific conservation measures are in place for this species, but most of the species range lies inside the Madeira Natural Park. Monitoring of population trends should be conducted to confirm species status.