Species

BackAgyneta rugosa Wunderlich, 1992

Agyneta rugosa Wunderlich, 1992

  • Kingdom: Animalia
  • Phylum: Arthropoda
  • Class: Arachnida
  • Order: Araneae
  • Family: Linyphiidae
EN Endangered
IUCN Red List Status:

Countries of Occurrence:
Portugal - Azores

Archipelago(s):
Azores

Reviewer/s:
Russell, N.

Contributor/s:
Lamelas-López, L. & Mendonca, E.

Facilitators / Compilers/s:


Assessment Rationale:

Agyneta rugosa is a money spider species restricted to Faial and São Miguel islands in Azores, Portugal (Borges et al. 2010). It has a relatively small Extent of Occurrence (EOO = 710 km²) and very small Area of Occupancy (AOO = 20 km²). The species is rare and only known from two subpopulations in the Natural Forest Reserves of Cabeço do Fogo (Faial) and Graminhais (São Miguel). In the past, the species has probably strongly declined due to changes in habitat size and quality. Currently, invasive plants Pittosporum undulatum, Hedychium gardnerianum and Rubus ulmifolius are changing some of the areas in the western range of the species and decreasing the quality of the habitat. Based on Ferreira et al. (2016) the habitat will further decline as a consequence of climate change. Therefore, we suggest as future measures of conservation: (1) regular monitoring of the species; and (2) control of invasive species namely Hedychium gardnerianum. Based upon the relatively small EOO and AOO of the species, and continuing decline of its habitat area and quality, it is assessed as Endangered. 

Geographic Range:

Agyneta rugosa is a money spider species restricted to Faial and São Miguel islands in Azores, Portugal (Borges et al. 2010), occurring in the Natural Forest Reserves of Cabeço do Fogo (Natural Park of Faial) and Graminhais (Natural Park of São Miguel). The estimated Extent of Occurrence (EOO) is 710 km2 and the estimated Area of Occupancy (AOO) is 20 km2 . 

Regions:
Portugal - Azores
Extent of Occurrence (EOO):
710 (km2)
Area of Occupancy (AOO):
20 (km2)
Elevation Lower Limit:
424 (m)
Elevation Upper Limit:
932 (m)
Biogeographic Realms:
Palearctic
Presence:
Extant
Origin:
Endemic Azores
Seasonality:
Resident

Population:

The species is rare and only known from two subpopulations one on Faial and another on S. Miguel island. The largest patch (Cabeço do Fogo in Faial) is currently being invaded by three plants (Pittosporum undulatum, Hedychium gardnerianum and Rubus ulmifolius), which are changing the structure of soil moss and fern occupation, with impacts on web construction. The surrounding area is already heavily invaded by the same invasive plants and parts are occupied by Cryptomeria japonica plantations. A continuing decline in the number of mature individuals is inferred from monitoring schemes and from the ongoing habitat degradation (Gaspar et al. 2011). Current Population Trend: Decreasing.

Habitat and Ecology

This species occurs in two fragments of native forest on Faial and S. Miguel islands (Azores). The largest one is dominated by Picconia azorica, Morella faya and Pittosporum undulatum (Cabeço do Fogo, Faial) and has a low index of habitat quality (Gaspar et al. 2011), the smallest one (Graminhais at S. Miguel) is dominated by Juniperus brevifolia and is located at high elevation with a high cover of bryophytes and ferns in the soil and keeps a pristine state (Gaspart et al. 2011). The species has an altitudinal range between 424 and 932 m. Adults were collected in summer. This species occurs in the soil, building a sheet web between small holes or mosses. Systems:  Terrestrial

Major Threat(s):

The species has probably strongly declined due to changes in habitat size and quality (Triantis et al. 2010). Currently, invasive plants Pittosporum undulatum, Hedychium gardnerianum and Rubus ulmifolius are dramatically changing the structure of the forest in the species' western range (Faial island). Based on Ferreira et al. (2016) the habitat will further decline as a consequence of climate change (increasing number of droughts, and habitat shifting and alteration). A change in rain regime due to climate change may also alter the cover of mosses and ferns, and change the habitat structure and quality in the currently pristine high elevation site (Gramimhais, S. Miguel island). The management of surrounding habitats, namely for Cryptomeria japonica plantations, may have also an impact on individuals.

Conservation Actions

The species is not protected by regional law, however, its habitat is in two regionally protected areas (Natural Parks of Faial and S. Miguel). Degraded areas, degraded due to invasive plant species (particularly in Cabeço do Fogo in Faial) should be restored and a strategy needs to be developed to address the current threat from invasive species and the future threat from climate change. Formal education and awareness are needed to allow future investments in restored habitats invaded by invasive plants; while further research is needed into its ecology and life history in order to find additional specimens at more sites and more islands within the current range dominated by native forest, and to obtain adequate information on population size, distribution and trends. An area-based management plan is also necessary for the most disturbed sites, including invertebrate monitoring to contribute to a potential species recovery plan. Monitoring every ten years using the BALA protocol will inform about habitat quality (see e.g. Gaspar et al. 2011).