Species

BackAgyneta depigmentata Wunderlich, 2008

Agyneta depigmentata Wunderlich, 2008

  • Kingdom: Animalia
  • Phylum:
  • Class: Arthropoda
  • Order: Arachnida
  • Family: Linyphiidae
CR Critically 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 depigmentata is a single-island endemic money spider species restricted to Flores Island in Azores, Portugal (Borges et al. 2010). It has a small Extent of Occurrence (EOO = 32-56 km²) and Area of Occupancy (AOO = 32-56 km²). The species is rare and only known from two subpopulations on Flores island, at the Natural Forest Reserves of Caldeiras Funda e Rasa and Morro Alto e Pico da Sé. The surrounding area is highly invaded by alien plants. In the past, the species has probably strongly declined due to changes in habitat size and quality. Currently, invasive plants (Hydrangea macrophylla, Hedychium gardnerianum and Rubus ulmifolius) are changing the habitat of the species in at least part of its range 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 future measures of conservation, including regular monitoring of the species and control of invasive species, namely Hedychium gardnerianum. Based upon the small EOO of the species, and the continuing decline of its habitat area and quality, it is assessed as Critically Endangered.

Geographic Range:

Agyneta depigmentata is a single-island endemic money spider species restricted to Flores island in Azores, Portugal (Borges et al. 2010), occurring in the Natural Forest Reserves of Caldeiras Funda e Rasa and Morro Alto e Pico da Sé (Natural Park of Flores). The estimated Extent of Occurrence (EOO) and Area of Occupancy are 32-56 km2 .

Regions:
Portugal - Azores
Extent of Occurrence (EOO):
32-56 (km2)
Area of Occupancy (AOO):
32-56 (km2)
Elevation Lower Limit:
373 (m)
Elevation Upper Limit:
900 (m)
Biogeographic Realms:
Palearctic
Presence:
Extant
Origin:
Endemic Azores
Seasonality:
Resident

Population:

The species is rare and only known from two subpopulations on Flores island. The smallest patch (Caldeira Funda e Rasa) is currently being invaded by invasive plants (Hedychium gardnerianum and Hydrangea macrophylla), which are changing the structure of soil moss occupation (Sphagnum spp.) 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 at least at Caldeira Funda e Rasa (Borges et al. 2016) 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 in Flores island (Azores). The largest one is dominated by Juniperus brevifolia (Morro Alto e Pico da Sé) (Gaspar et al. 2011), and the smallest one (Caldeira Funda e Rasa) is dominated by Juniperus brevifolia and Ilex perado subsp. azorica and is currently heavily invaded by Hedychium gardnerianum and Hydrangea macrophylla. Rubus ulmifolius is also spreading changing the structure of the habitat. The species has an altitudinal range between 373 and 900 m. Adults were collected in summer. This species occurs in the soil associated with Sphagnum spp. building the sheet web between small holes in the Sphagnum spp. soil cover. The species occurs both inside dense forest and in open Sphagnum spp. bogs. Systems:  Terrestrial

Major Threat(s):

In the past, the species has probably strongly declined due to changes in habitat size and quality (Triantis et al. 2010). Currently, invasive plants Hydrangea macrophylla, Hedychium gardnerianum and Rubus ulmifolius are dramatically changing the structure of the forest in the species' southern range. 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 regime of rain due to climate change may also alter the cover of Sphagnum spp. and change the habitat structure and quality. The management of surrounding habitats, namely for Cryptomeria japonica plantations, may have also had an impact on individuals.

Conservation Actions

The species is not protected by regional law. Its habitat is, however, in a regionally protected area (Natural Park of Flores). Degraded areas, degraded due to invasive plant species (particularly in Caldeira Funda e Rasa) should be restored, and a strategy needs to be developed to address the current threat by invasive species and the future threat from climate change. Formal education and awareness is 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 within the current suspected range, which is 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).