Burrowing seabirds and spiders

Application for Scientific Permit – Available for Public Comment

Public comment on the following application for a Scientific Research (Fauna) Permit is open until 17 October.

Applicant: Threatened Species Recovery Hub, University of Queensland.

Species/Taxon: seabirds, spiders

Locations: Courts Island, Partridge Island, Wedge Island, Tasman Island, Cape Queen Elizabeth and Whalebone Point (Bruny Island), Maatsuyker Island

Title of research: Quantifying island ecosystem recovery following invasive mammal eradications

Aim of project: Investigate a cost and time-effective means for quantifying the progression of island ecosystem recovery following invasive mammal eradication.

Justification: Invasive mammal eradication is key for restoring island ecosystems, however recovery is not always assured. Monitoring is key to assess whether the desired conservation outcomes are achieved. Monitoring informs when management or active restoration are required, and can assist in determining unanticipated consequences or detrimental effects, such as population increases of invasive species or failure of species recovery. Monitoring provides managers, decision makers, funders and other stakeholders to assess project success, ultimately informing the return on investment for island conservation projects. It also inform future island projects and can influence their capacity to obtain funding. Ideally, all species and their interactions would be monitored pre- and post-eradication to assess recovery, however this is rarely feasible. Globally, ecosystem monitoring following invasive species eradications is sporadic and at times, ad hoc. Insufficient funding following expensive eradication projects, logistical challenges, cryptic complex species interactions, and often the decades required to detect population trends results in either no monitoring, or monitoring of only a few select species. We aim to explore the role and efficacy of cost- and time-effective monitoring techniques for evaluating ecosystem recovery. This research will investigate novel techniques to monitor ecosystem restoration following eradication and also determine seabird densities. In addition, this work will provide new biodiversity information and in some instances, new information on seabird phenology and habitat on key Tasmanian islands.

Maximum likely numbers of individuals involved: An estimated maximum of 500 spiders will be sampled per study site over the three-year course of this study. An estimated maximum of 200 seabird burrows per species may be burrow-scoped per study site over the three-year course of this study.

Activities undertaken and methods: Spider collection will be undertaken in conjunction with soil, plant, algae, seabird guano and freshwater sample collection. For each study site, two to three transects (depending on island size, logistics, site sensitivities and topography) will be established from the shoreline to high elevation. Transects will cross vegetation and soil gradients and be proximal to seabird sites. Along each transect we will collect spider samples at multiplicative distances per vegetation type or colony boundary (e.g. 0m, 20m, 40m, 80m, 160m etc., up to a maximum of 1km). Transect locations are flexible based on logistics, topography and wildlife sensitivities and exact locations will be determined based on discussion with authorities (relating to any wildlife sensitivities) and landscape features. Spiders will be collected directly from the leaf litter or via small (7cm diameter) invertebrate pitfall traps. All samples will be transported back to the University of Tasmania for stable isotope analysis.
This work will be focused on key Tasmanian islands. It is complimented by a much larger study, which spans over 40 Australian, New Zealand and sub-Antarctic islands.  For these Tasmanian sites: Bruny Island sites, Courts Island, Partridge Island, George Rocks and Maatsuyker Island, we aim to establish three to five repeat sampling sites where samples will be collected several times through the year (subject to logistics). These samples will enable us to determine any effect of season and local weather on stable isotope results. Where possible, repeat sampling will be coordinated with existing/ established programs working at these locations, in order to minimise impacts and island visitation.

Seabird surveys will also be undertaken on these key Tasmanian Islands to investigate the relationship between stable isotope signatures and seabird colony densities. Seabird species presence and abundance will be assessed using a combination of ground surveys and remote camera and acoustic recorder units. Ground surveys will involve counts of burrow entrances for subsets of colonies using quadrats or transects, where appropriate. Where required, burrow scoping may be used to assess burrow occupancy levels and species identification at some sites. A combination of remote motion triggered cameras and acoustic recorders (maximum of 5 units per study site) will be used to document seabird phenology and indicate abundance over the 12-month period. Units will be situated in colonies to ensure they do not obstruct seabird flight paths or landing areas. Where possible, seabird monitoring will be done in collaboration with existing and established projects working at each study site. DPPIWE will be consulted regarding the timing of site visits to minimise wildlife disturbance.

Fate of animals: Seabirds will not be handled or removed from their nests. Spiders will be placed in ethanol on site and transported back to the University of Tasmania for processing. Pitfall trapping can result in some by-catch of non-target invertebrate species. Any non-target invertebrate species will be preserved for identification and the data provided to TMAG and DPIPWE.

Likely impact on species involved (including any by-catch): Seabirds may experience brief, low-level disturbance due to burrow scoping and movement in human movement in the vicinity of the colony. All efforts will be taken to ensure the duration and level of disturbance is minimised. The timing of surveys will be determined in consultation with authorities. Where possible, seabird monitoring will be done in collaboration with existing projects already working at several proposed sites. Relevant authorities will be consulted with regarding the timing of site visits to minimise all wildlife disturbance.
When collecting spiders using pitfall traps, we anticipate some incidental invertebrate by-catch, which is normal procedure for pitfalls. We will ensure this is minimised by using small diameter pitfalls (7cm).

Contact

Scientific Research Permits
Natural Values Conservation Branch
134 Macquarie Street
Hobart TAS 7000
Email: Scientific.Permits@dpipwe.tas.gov.au

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