Lamelas-López, L. & Mendonca, E.
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Cheiracanthium jorgeenses is a single-island endemic spider species restricted to São Jorge island in Azores, Portugal (Borges et al. 2010). It has a small Extent of Occurrence (EOO = 14-28 km²) and Area of Occupancy (AOO = 8-28 km²). The species is rare and is only known from two subpopulations in S. Jorge island, at Natural Forest Reserves of Topo and Pico Pinheiro, with the surrounding area being highly invaded by alien plants and pasture management. In the past, the species has probably strongly declined due to changes in habitat size and quality. Currently the invasive plant Hedychium gardnerianum and dairy-cattle disturbance are changing some of the areas and decreasing the quality of the habitat. Based on Ferreira et al. (2016) the habitat will further decline as a consequence of climate change. The species is assessed as Endangered (EN). We suggest as future measures of conservation: (1) a long-term monitoring plan of the species; (2) control of invasive species, and (3) restriction of access of cattle to native habitats.
Cheiracanthium jorgeenses is a single-island endemic spider species restricted to São Jorge island in Azores, Portugal (Borges et al. 2010), occurring in the Natural Forest Reserves of Topo and Pico Pinheiro (Natural Park of S. Jorge). The estimated Extent of Occurrence (EOO) is 14-28 km2 and the estimated Area of Occupancy (AOO) is 8-28 km2 .
This is a very rare species and is only known from two sustainable subpopulations with very few individuals found during BALA project intensive sampling (Borges et al. 2016). A continuing decline in the number of mature individuals is inferred from monitoring schemes and from the ongoing habitat degradation due to invasions of alien plants (namely Hedychium gardnerianum) and degradation due to soil trampling by dairy cows, creating gaps in the tree cover, which increases the wind impact in the canopies. Current Population Trend: Decreasing.
This species occurs in two fragments of native forest in S. Jorge island (Azores), with an altitudinal range between 585 and 941 m. The largest one is dominated by Juniperus brevifolia and Ilex perado subsp. azorica (Topo) and keeps some pristine state (Gaspar et al. 2011), but the smallest one (Pico Pinheiro) is dominated by Juniperus brevifolia and Erica azorica and is currently heavily invaded by Hedychium gardnerianum, which is changing the structure of the habitat. Dairy cattle are changing the structure of the habitat in Pico Pinheiro, decreasing the quality of the habitat (Gaspar et al. 2011). 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), and the species seems to have survived only at two sites at mid and high elevation native forest of S. Jorge island. The main current threats are: a) the spread of an invasive plant species, Hedychium gardnerianum, which is changing the structure of the forest; b) soil erosion due to trampling by dairy cattle (cattle are entering the native areas in S. Jorge island without control by the Conservation Managers), creating gaps in the tree cover, which increases the wind impact in the canopies. The management of surrounding habitats, namely for Cryptomeria japonica plantations, may have also an impact in individuals expanding for those sites. 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 species is not protected by regional law, but its habitat is in Natural Forest Reserves. Degraded areas, degraded due to invasive plant species (particularly in Pico Pinheiro) should be restored and a strategy needs to be developed to address the current threats from invasive species and habitat disturbance by cattle, 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 © The IUCN Red List of Threatened Species: Cheiracanthium jorgeense – published in 2021. https://dx.doi.org/10.2305/IUCN.UK.2021-1.RLTS.T58082591A58082627.en 3endemic species of if there are more species restricted to other islands that are currently assigned to the exotic C. 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).