A national islands database and assessment of conservation value

Transcription

1 A national islands database and assessment of conservation value Julie Quinn and Karl Bossard Spotted-Tailed Quoll (D.Watts) Feral pig (B. Salau) Glossodia orchid (S.Bourne) Tracking and Tasman Island (S. de Salis)

2 A national islands database and assessment of conservation value 1. Offshore Islands database. 2. The Department of Sustainability, Environment, Water, Population and Communities has compiled a database of details about feral animals on all of Australia s offshore islands. 3. DSEWPAC commissioned further work by Ecosure to develop a ranking of conservation status of offshore islands >200 ha and to prioritise the top islands around Australia.

3 Offshore Islands Database GIS spatial coverage of essentially all offshore islands. Currently 9,276 islands with about half of the islands being less than 1 ha in size. Covers all of Australia including all external territories other than Antarctica. Based on Geoscience Australia s 100k mapping supplemented from other sources including hand digitising from satellite imagery and scanned marine charts. Includes a unique island ID, alternate names, the archipelago or island group to which each island belongs, state, tenure, spatial data source, distance to mainland, latitude and longitude, and area. Using unique island ID, links to Feral Animals on Islands and Weeds on Islands databases.

4 Photo: IACRC Feral animals on offshore islands database The objective of having the database is to assist the states, territories and other land managers to manage the islands under their jurisdiction through identifying feral animals on offshore islands, prioritising islands for biodiversity conservation, and linking people and projects together. Photo: D. Nelson The feral animals on offshore islands database currently has more than 2,000 records for 154 species on 523 islands. A Microsoft Excel version can be downloaded from: /biodiversity/invasive/ ferals/islands/index.html Photo: B. Salau

5 Feral animals on islands database The feral vertebrates on islands database has a focus on feral animals and provides: A list of all islands of any size with known populations of introduced vertebrate animals. Includes native species that have been introduced to islands on which they do not naturally occur. Includes birds, mammals, reptiles, frogs and fishes. Links to the Offshore Islands Database which contains information such as archipelagos where an animal may, once established on one island, disperse quickly to others, including small islets. Includes island name, archipelago, and state, so it can stand alone from the GIS spatial layer. Includes common and scientific name, whether the species is currently thought to be present, eradicated, etc., reference to source data, and other information.

6 Example extract Islands in part of an archipelago helps identify where species may move between the islands Unique ID that links to the other DSEWPAC databases Reference and dates or other important information about age and source of the data

7 Prioritisation of high conservation status offshore islands A report prepared for DSEWPAC by Louise Shilton, Ecosure Pty Ltd in collaboration with Ray Pierce, Eco Oceania Ltd, in Gives a biodiversity value for offshore islands based on threatened species listed under the EPBC Act (Species profile and threats database) and/or state/territory legislation; marine and migratory species (listed under the conventions from Bonn, CAMBA, JAMBA, ROKAMBA) and the threat posed by invasive vertebrate pests. The report prioritises the top 100 islands >200 ha.

8 Methodology A total biodiversity value was calculated for every island by using an intrinsic biodiversity value x biodiversity presence value. Photo: G. Curry Intrinsic value based on EPBC Act status, listed migratory and state/territory listed. e.g. Critically endangered = 4; endangered = 3; vulnerable = 2, migratory or other listing = 1. Presence value based on threatened species data under the EPBC Act. E.g. Known (confirmed records) = 3; likely = 2; may = 1. Photo: G. Curry

9 Methodology cont. Photo: N. Hamilton A value for the total feral value was given as an indication of the potential of environmental impact by the invasive animal. Intrinsic feral value is based on their impact. E.g. EPBC Act KTP or major concern = 4; high impact = 3; medium impact = 2; low impact = 1. Presence value is based on the known range of the species. E.g. Known and free-ranging = 3; restricted range = 2; domestic only = 1.

10 Methodology cont. The islands were sorted: 1. By their total biodiversity value 2. By their total feral value, such that if two islands had the same biodiversity value, the island with a higher total feral value would rank lower. 3. By a matrix consideration of specific feral-threatened species impacts (e.g. Cats are known to predate on burrowing sea birds). Photo: A. Ferguson

11 Output 100 priority islands (>200 ha) were determined and sorted into the top 50 and lower 50. Photo: Paradise Ink No ranking within the top/bottom 50. For each priority island a detailed profile has been compiled. Archipelago or island group; location; size; jurisdiction; tenure; geography; demography and human use; threatened species; feral animals; other threats; pest management and monitoring; potential eradication and biosecurity risks; recommended actions; and references.

12 Priority 100 high conservation status islands >200 ha

13 Application of the prioritisation of the high conservation status islands This report is useful in two ways: 1. It can provide land managers and decision makers an overview of how their islands stack up against others. 2. The methodology can be used to analyse other data sets or other data sets can be compiled with the data used here for a prioritisation that includes other components (e.g. Include an evaluation of flora quality or weeds present).

14 Other concepts that could be included A similar exercise was undertaken to identify high conservation status mainland islands in a report prepared by Ecological Australia. Some of the conservation values and analytical techniques could be useful in further determining the value of offshore islands. Measurements of species richness, level of endemism, presence of native vegetation, important aquatic ecosystems or wetlands, and the presence of arid and semi-arid refugia are all data sets that exist for Australia so could be applied to islands. It may also be possible to utilise data sets from smaller areas. e.g. state level data.

15 Other databases related to islands The Department has other databases: Establishing a Weeds on Offshore Islands database though this is not yet nationally comprehensive. Have a Sea Bird Breeding Location database that also links to the Offshore Islands database. Considering producing a marine turtle breeding location database that similarly links. Also a database of significant threatened species populations on offshore islands.

16 Summary The department has lots of valuable information that the Island Rescue and others can use when putting together analyses of the value of our islands We would welcome the input of updates to the datasets. Photo: N. Bryden Photo: Customs