Lamelas-López, L. & Mendonca, E.
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Cheiracanthium floresense is a single-island endemic species restricted to Flores island in Azores, Portugal (Borges et al. 2010). It has a small Extent of Occurrence (EOO = 20-56 km²) and Area of Occupancy (AOO = 20-56 km²). The species is rare and only known from two subpopulations, at Natural Forest Reserves of Caldeiras Funda e Rasa and Morro Alto e Pico da Sé. The surrounding area is highly invaded by alien plants, and 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 some of the areas of the species' 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. Based upon the small EOO of the species and continuing decline of its habitat area and quality, it is assessed as Critically Endangered. Therefore, we suggest as future measures of conservation: (1) regular monitoring of the species; and (2) control of invasive species namely Hedychium gardnerianum.
Cheiracanthium floresense is a single-island endemic 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) is 20-56 km2 and the estimated Area of Occupancy (AOO) is 20-56 km2 .
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). 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.
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), but 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 and 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 mostly in the canopy of endemic trees associated with leaves of Ilex perado subsp. azorica and Laurus azorica in which it builds the web capsule. Systems: Terrestrial.
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). The management of surrounding habitats, namely for Cryptomeria japonica plantations, may have also had an impact on individuals.
The species is not protected by regional law, but its habitat is in regionally protected areas. 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 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 within the current range dominated by native forest, and to obtain adequate information on population size, distribution and trends. In addition, there is the need of an integrative taxonomic revision of the genus in Azores to evaluate the status of the two single-endemic species and verify if they are valid endemic species or if there are more species restricted to other islands that are currently assigned to the exotic Cheiracanthium erraticum. 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).