Habitat Monitoring and Mapping

Amy-Jayne Dutton

St Helena National Trust

DPLUS040

Securing the Future for St Helena’s endemic Invertebrates

Habitats across St Helena

St Helena has a number of habitats found nowhere else on earth (Cronk, 1989; Lambdon, 2012). In association with these, there is also a high diversity of endemic invertebrates. Few areas of endemic vegetation remain due to the impact of human settlers, goats, rabbits and other introduced species. Understanding the abundance, distribution, and diversity of remaining areas of endemic vegetation, along with the effectiveness of restoration areas at supporting native invertebrates, is crucial for the effective management of these sites and their associated fauna. Endemic vegetation includes Scrubwood Commidendrum rugosum (Vulnerable), St Helena Gumwood Commidendrum robustum (Critically Endangered), St Helena Dogwood Nesohedyotisarborea (Critically Endangered) and Whitewood Petrobium arboreum (Endangered).

Scrubwood habitat is typically between 200m and 400m on the edges of the island, on the edges of St Helena. It is dry, with sparse vegetation; introduced species in these areas includes Wild Coffee (Chrysanthemoides monilifera), Lantana (Lantana camara) and Tungi (Opuntia elatior, O. ficus- indica). Generally small areas of this endemic vegetation can be found around the island, with a key stronghold on Blue Point. Gumwood habitat is typically mid altitude, ranging between dry and moist climates. Peak Dale is the largest stand of natural Gumwoods remaining, with other trees scattered around the island, including several individuals at Thompsons Wood 1.5km away. Forestry species such as Eucalyptus (E. grandis), Cape Yew (Afrocarpus falcata) and invasive non-natives including Whiteweed (Austroeupatorium inulifolium) and Wild Mango (Schinus terebinthifolius) surround and are invading this small area of native habitat. Cloud Forest habitat contains five endemic tree species, all of which are threatened on the IUCN Red List of Threatened SpeciesTM with endemic ferns including Tree Fern (Dicksonia arborescens) also making up a significant portion of the native vegetation. Portions of cloud forest were removed for flax (Phormium tenax) which is now unmanaged on larger portions of land. Substantial portions of the Peaks are also covered in non-native species including Pheasant tail fern (Nephrolepis cordifolia) and Whiteweed, with Fuchsia (F. coccinea) growing through and swamping areas of vegetation. Restoration attempts have so far focussed on vascular plant propagation.

As part of the Darwin Plus project DPLUS040 sites of natural regeneration and restoration efforts for endemic plants were identified to map and assess for their invertebrate value. Key areas identified were: Peak Dale – natural endemic Gumwood site Millennium Forest – restoration Gumwood site Blue Point – natural and restoration Scrubwood site Pipe Path – natural Scrubwood site Flagstaff – natural Scrubwood site High Peak (Ginger Patch) – restoration cloud forest site

Map 1. Sites identified for habitat mapping by DPLUS040

Originally it was planned to survey all individual endemic trees in Millennium Forest and other areas, this was not efficient or time effective and this output was changed to map and monitor these areas more broadly. Additionally, the need to map the habitats of St Helena was also recognised by SHG following the application for DPLUS040 and another Darwin Plus project (DPLUS052) undertook remote sensing as well as ground-truthing to map the entire island. Therefore the maps that follow are based on these (produced June 2018), with finer scale surveying needed to complement this and update this map. A summary of vegetation and some key invertebrate findings follows.

Large areas of land across St Helena are the responsibility of St Helena Government (SHG), with native areas being overseen by its Environmental Management Division (EMD), with input from other organisations including the St Helena National Trust and St Helena Nature Conservation Group. Some areas belong to private land owners, being either privately managed or with permission granted for conservation efforts to be undertaken. As part of the Landscape and Environmental Mitigation Project (LEMP), areas of native vegetation were surveyed, with key habitat (Peak Dale and Blue Point) fenced as part of mitigation for the area lost by the airport construction. Extensive areas of new planting are also being undertaken, particularly along the Haul Road, which links with plantings at Millennium Forest.

Monitoring across St Helena

A basic habitat monitoring methodology was developed as part of the Community Forest project (Darwin Initiative Community Forests Project 005-020) and has been utilised here. Additional information has been gained by using the DPLUS052 method on the ground.

Invertebrate monitoring Currently invertebrate surveys are ad hoc and there is no effective monitoring in place across the island for informing conservation efforts. Conservation efforts have most frequently focussed on improving habitat by increasing native and endemic plant presence, with invertebrate presence not being of primary importance. Methods should be put in place for basic monitoring, with consideration that specialists are needed for some species or groups. Invertebrate monitoring, along with vegetation surveys, will allow comparison of conservation efforts and their impacts on invertebrates. The surveys undertaken by DPLUS040 have provided invertebrate information for a number of areas, and results from these can be used to inform a monitoring methodology.

Recommendations Numerous specimens have been collected as part of DPLUS040. Non-destructive monitoring methods should be utilised moving forward, with minimal specimens needing identification using the microscope to be collected. Outcomes of monitoring should be clearly defined and agreed with SHG to ensure that this is efficient, effective, and will provide suitable information to inform conservation efforts. This also includes sites.

Selection of Sites Some of the sites identified in this document are areas where long-term monitoring through malaise traps was undertaken. In two of these sites the weather was too severe and malaise trap information is limited (BLUS and PIPE). Specialist entomologists Howard Mendel (Coleopterist) and Timm Karisch (Lepidopterist) also visited sites across the island, greatly increasing knowledge and understanding of the invertebrate usage of these sites. While the sites originally identified are clearly of value, from the evidence provided in the Invertebrate Report (Fowler et al. unpublished), it is obvious that areas of non-native vegetation can support native as well as non-native invertebrates. This requires further scrutiny to establish the degree to which species are truly habitat specific.

Following this project (DPLUS040) it is clear that the spread of invertebrates across the island is not clearly defined by native and non-native habitats or any clear boundary. Therefore, although the sites identified by this project as of interest and value to potentially rare specialist invertebrates, consideration of other areas should also be made. It is recommended that areas of non-native habitat are identified for monitoring as well as native habitat, to assess usage by endemic invertebrates, as well as monitoring spread of non-native species.

Following work from DPLUS040 recommended sites for monitoring are Peak Dale, Blue Point, Flagstaff, High Peak, the Peaks and Millennium Forest. Prosperous Bay Plain would also benefit from regular monitoring due to the rare and sensitive nature of this habitat. These are well established, accessible sites receiving conservation work and or representing areas where improvements for invertebrate conservation are feasible. Due to Signal Houses location on the other side of the airport, it is not practical to regularly monitor this site. While Pipe Path is an accessible area of Scrubwood, it may be of limited value to monitor, unless additional conservation efforts are also undertaken in or around this area.

Additional sites should be considered which would represent areas where invasive species may spread to, act as points for detection of new species, or non-native areas to determine endemic invertebrate use of novel habitat types. Ruperts Valley, while barren, had several interesting invertebrate finds (Fowler et al., unpublished) and is also close to the location where container are unloaded. The Heart-shaped waterfall is another site close to human habitation, with numerous non-native species. Other sites should be informed by conservation priorities.

Methods should be undertaken on a regular basis, with simple surveys undertaken biannual or annually. It has been suggested that moth trapping at a number of locations for a discrete period of time could be undertaken at less regular intervals (3-5 years) to provide sufficient data to assess changes in species assemblages and abundance.

Methods  Point monitoring o Hand searches o Observations o Sweep net o Light trapping (moths)  Fixed point photography to assess changes o Original malaise trap locations provide a replicable location

Summary of natural and conservation areas and their invertebrate value

Map2. Peak Dale – Natural Gumwood site with new plantings

This is the largest remaining site of naturally occurring Gumwood woodland. It has been fenced (by LEMP) to exclude livestock and encourage natural regeneration. It is not too far from other native vegetation types (Cloud Forest on High Peak) but these differences in vegetation may only support movement of non-specialists. The closest Gumwood site is Thompsons Wood and may not be travelled easily by non/weak flying invertebrates (e.g. bugs/ micro moths). The malaise trap locations also represent suitable monitoring points, including for fixed point photography.

Peak Dale – older vegetation (PEOL) Endemic Other Gumwood (Commidendrum robustum) Blue weed (Ageratum conyzoides) Lichen (found on gumwoods) Bilberry tree (Solanum mauritianum) Ink bush/poison ink (Cestrum laevigatum) Summer grass (Ehrharta erecta)

Peak Dale – new plantings (PENE) Endemic Other Gumwood (Commidendrum robustum) Lantana (Lantana camara) Sweet spoor (Pittosporum undulatum) Cape yew (Afrocarpus falcata) Flax (Phorium tenax) Summer grass (Ehrharta erecta)

Invertebrate Value For the malaise surveys both sites at Peak Dale was found to be in the top 10 sites for the highest diversity and abundance for identified species. Several Opogona moths were found in this site as well as the St Helena plume moth Agdistis sanctaehelenae was found in August. The trees are covered in lichens which may support additional species to those that feed directly on the trees themselves. The endemic tumbling flower beetle Glipostenoda mellissiana appears linked to endemic Compositae (Gumwood and Scrubwood) and was found in highest numbers at Peak Dale. (Fowler et al., unpublished).

Map 3. Millennium Forest- Restoration Gumwood site

This is a new restoration site at the edge of an area that was once referred to as the Great Wood. Established in 2000, this is a predominantly Gumwood area, with other endemic species also propagated. There are now LEMP plantings alongside this as airport mitigation works which will improve connectivity and benefit overall conservation impact. Eight locations have been selected for monitoring, including with fixed point photography, these provide continuity with those previously utilised by Community Forest project.

ENDEMIC NON-NATIVE Gumwood (Commidendrum robustum) common saltbush (Aptriplex semibaccata) Ebony (Trochetuipsis ebenus) African olive (Olea europaea subsp. Africana) Hair grass (Eragostis saxatilis) Old man salt bush (Atriplex nummularia) Diddly dight/black nightshade(Solanum nigrum) Poison peach (Diospyros dichrophylla) Tantocury (Chenopodium ambrosioides) Lantana (Lantana camara) Prickly sow-thistle (Sonchus asper) Blue weed (Ageratum conyzoides) Lesser swinecress (Coronopus didymus)

Invertebrate Value Endemic invertebrates are present on this site, including Loveridges Hoverfly (Sphaerophoria beattiei), Gumwood Leafhopper (Sanctahelenia decelli), which may represent species that easily disperse. As there are no original areas of Gumwoods remaining nearby, it is unlikely to gain truly specialist species with low dispersal ability and additional actions may need to be assessed (e.g. translocation).However, at Millennium Forest 114 species were found in malaise trap samples, with 21 endemic species, these endemic species constituted more than half (53%) of the specimens collected from this site. Simple analysis by Timm Karisch (Fowler et al. unpublished) shows that Millennium Forest is beginning to accrue species linked with the Gumwood vegetation of Peak Dale. Continuing monitoring will be beneficial to document invertebrate assemblage changes as the forest matures.

Map 4. Blue Point – Natural and Restoration Scrubwood site

This is an exposed, steep site, with often misty and windy conditions. It is mostly barren with sparse vegetation, but has a population of mature Scrubwoods. There is deadwood present and lichens on the rocks and vegetation. This vegetation has been subject to grazing by livestock (sheep) and rabbits and this severely impacts recruitment. There has been low establishment of young plants installed in restoration attempts, although there are a number of young wild seedlings. As part of mitigation works a fence has been installed (2018), including rabbit drop traps, to exclude feral livestock and reduce the rabbit population, to increase survival of seedlings. The map identifies the areas of mature scrubwoods not identified by the remote sensing for DPLUS052. Seven locations have been selected for monitoring, including with fixed point photography, these provide continuity with those previously utilised by Community Forest project.

Plants ENDEMIC NON-NATIVE Scrubwood (Commidendrum rugosum) Furze (Ulex europaeus) Lichens Soft rush (Juncus effusus) Flax (Phormium tenax) Raspberry (Rubus rosifolius) Bilberry tree (Solanum mauritianum) Bermuda cedar (Juniperus bermudiana )

Invertebrate Value Two malaise traps were originally set up across the site, one in natural vegetation and another in restoration area, but conditions were too severe at the site of natural vegetation so results from this site are limited (see Fowler et al., unpublished). Hand searches have also been undertaken. This site has low species diversity, but a third of identified species are endemic, with other specimens awaiting scientific description. It is likely that some unidentified specimens are rarer species that require expert identification. It is now a good opportunity for monitoring of this site to be implemented, due to the installation of the fence which is likely to positively impact plant survival, both of the native and non-native vegetation.

Map 5. Pipe Path – Natural Scrubwood site

This site consists of two tiny remnants of Scrubwood habitat, next to the newly constructed Haul Road. This is a small site and the remote sensing undertaken by DPLUS052 could not pick up all of the fine detail of these areas. There are lichens present but little natural regeneration. This map will be updated to include the area and number of scrubwood plants. Due to the size of the site, one point will be utilised for monitoring.

Plants Endemic Other Scrubwood (Commidendrum rugosum) White tungy (Opuntia ficus-indica) Lantana (Lantana camara) Creeper (Carpobrotus edulis) Wild coffee (Chrysanthemoides monilifera) Common saltbush (Aptriplex semibaccata)

Invertebrate Value A malaise trap was initially set up at this site, but conditions were too exposed so results from this site are limited (Fowler et al., unpublished). Hand searches have also been undertaken and a moth trap was also run for an evening. Unsurprisingly for a site of its size, there have been few remarkable finds from this site, although seven endemic species recorded including the specialists Scrubwood leafhopper Atlantocella lelupi and St Helena Scrubwood Plant-bug. This site is may be useful to monitor as a small remnant site, to establish whether these areas can maintain viable populations of endemic invertebrates or if they are functionally extinct.

Map 6. Flagstaff – Natural Scrubwood site

This is also a small remnant of Scrubwood habitat. The fine detail appears not to have been picked up by the methodology employed and this map will be updated with area and number of scrubwoods. However it is a larger area than the Pipe Path Scrubwoods. This site is approximately 2km from Pipe Path Scrubwoods, the closest site. This site has had recent habitat management by LEMP as part of mitigation efforts. This map will be updated to include the area of Scrubwood plants. Two points have been selected where monitoring and fixed point photography will occur.

Native Non-native Scrubwood (Commidendrum rugosum) Wild coffee (Chrysanthemoides monilifera) Lantana (Lantana camara) Fiddler tree (Acacia longifolia) Tungi (Opuntia elator)

Invertebrate Value Several Scrubwood specialists have been found at this site including Scrubwood leafhopper (Atlantocella leleupi) and the St Helena Scrubwood Plant-bug (Insulopus asteri). It is a small area, which still retains some specialist invertebrates. A visit by specialist lepidopterist didn’t find much lepidopteran interest. However, this site is a valuable Scrubwood remnant, at a distance from other sites to reduce likelihood of successful migration. It has been a historic Scrubwood site therefore has considerable conservation value.

Map 7. High Peak Ginger Patch– Restoration Cloud Forest site

This site is substantially different to the others mapped, being an area of moist cloud forest vegetation with a complex assemblage of both plants and animals. This site was an area of Ginger (Hedychium flavescens) with a canopy of Cape Yew (Afrocarpus falcata) and where the Ginger has been removed and planted with a number of endemic species. Endemic ferns are often present in the understorey of Cape Yew and black scale fern is abundant here. This site is on the sheltered (north-west) side of High Peak, which has natural cloud forest vegetation on the exposed site (south east). Monitoring and fixed photography will be undertaken at the malaise trap location.

Endemic Other She cabbage tree (Lachanodes arborea) Sticky fern (Hypolepis villoso-viscida) Black scale fern (Diplazium filamentosum) Blue weed (Ageratum conyzoides) Dwarf jellico (Berula burchellii) Whiteweed (Austroeupatorium inulifolium) He cabbage (Pladaroxylon leucodendron) Cardinal grass (Paspalum urvillei) Dogwood (Nesohedyotis arborea) Whitewood (Petrobium arboreum)

Invertebrate Value The DPLUS040 project has provided the first opportunity to undertake a detailed invertebrate survey of this area. The natural vegetation on the south easterly side of High Peak has received attention, but information from the restoration area provides data on species utilising the new vegetation. A number of endemic species have been found on this site (Fowler et al., unpublished), some of which have only been found on Cloud Forest sites. Analysis by Timm Karisch (Fowler et al., unpublished) has shown that species here are similar to other Peaks sites. This shows great potential for this site to support cloud forest invertebrates.

Acknowledgements Thanks to Liza Fowler, Sheena Isaac, Natasha Stevens, Sasha Bargo, Mike Jervois, Timm Karisch, Shayla Ellick, Mikko Paajanen, Elizabeth Cairns-Wicks and Sam Cherrett for help with fieldwork and map production.

Map produced by St Helena National Trust for Darwin Plus project DPLUS040 Habitat classification open data sourced from St Helena Government, supported by Darwin Initiative Funding (DPUS052) Gumwood and fence line data provided by LEMP Satellite Image © CNES 2014, Distribution Airbus DS / Spot Image