Habitat Project

The Identification of Significant Shorebird Areas in Australia: Mapping, Thresholds and Criteria.

This project, funded by the Australian Government’s National Heritage Trust, was completed in June 2008. The information that came out of this project has been vital for informing the development of the a national shorebird monitoring protocol for the Shorebirds 2020 Program. Download the final report [pdf: 784kb].

Recognising nationally significant shorebird areas

This work also informed on the importance of recognising nationally, as well as internationally significant shorebird habitat. These recommendations have been incorporated into a Draft EPBC Act policy statement 3.21 – Significant impact guidelines for 36 migratory shorebird species.

And have also been published in Diversity and Distributions:

Clemens, R. S., Weston, M. A., Haslem, A., Silcocks, A., and Ferris, J. (2010) Identification of significant shorebird areas: thresholds and criteria. Diversity and Distributions 16:229-242.  http://www3.interscience.wiley.com/journal/123298867/issue

Background
This project has had three phases including a review of what we know about migratory shorebirds, the identification and mapping of important shorebird areas, and testing to determine if additional criteria should be used to identify nationally significant sites for migratory shorebirds.  Thirty-six migratory shorebird species regularly visit Australia, and these migrants require highly productive sites to meet their high-energy needs during their long-distance movements in the non-breeding season.  International treaties have been established to protect these species, and this project will further inform decision-makers on how best to ensure the conservation of these amazing birds and the habitats they use.

Review of Migratory Shorebirds in Australia

The migratory shorebirds that regularly visit Australia are a diverse group of species with a wide variety of habitat requirements, spatial distributions, and patterns of habitat use.  For this project focus will be on those species which regularly return to the same areas year after year, and tend to aggregate in relatively large numbers.  Species which are highly dispersed or with lower site fidelity will be left for future studies.  A review of the distributions and population trends of migratory shorebirds show some clear trends that are being witnessed throughout the world as well as here in Australia.  Many populations of migratory shorebirds are declining.  Throughout Australia the surveys conducted by the Australian Wader Study Group (AWSG) clearly demonstrate population declines for Curlew Sandpiper and Eastern Curlew (with 10 other species showing some evidence of decline), and some species appear to be disappearing from the southern most part of their range.  Further, Atlas data demonstrate that some species are declining in parts of Australia where development has likely degraded the habitat of wetlands used by migratory shorebirds.  This is most evident in some coastal areas of eastern Australia.  It is unclear what role the loss of wetlands in Australia has had in these population declines, however, it is clear that as the final destination for many shorebirds in the non-breeding season, the conservation of habitat for shorebirds in Australia is critical to their long term survival.

Review of Population Monitoring,  Gosbell, K. and R. Clemens

Identification and Mapping of Sites

A GIS that has been created provides a much-improved picture of shorebird use in Australia by spatially identifying site-complexes, sites, sub-sites as well as feeding and roosting areas.  Where possible for every migratory shorebird site that has been mapped, we have summarized the kind of shorebird use, described the habitat, and identified potential threats.  There still are many holes in our understanding of what areas in Australia are being used by migratory shorebirds, and there will need to be some revision of shorebird site boundaries.  However, it is hoped that this project will be the first step in a process of continuing to revise and add to our knowledge of important shorebird areas throughout Australia.

Definitions

A site here is defined as the entire area of contiguous habitat used by the same group of shorebirds, which may include multiple discrete roosts and feeding areas. Anecdotal evidence suggests that movement between sites (areas of contiguous habitat) is not unusual, and where local expertise suggests it does occur, all sites suspected as being used by the same group of birds should be surveyed at the same time as if it were one site.  Identification of these site-complexes and other relatively closed populations should in theory reduce the annual variation and thus increase the sensitivity of analysis.

Criteria Testing

Significant effort has been put into identifying migratory shorebird sites of international significance, but that has left many seemingly important sites out.  We hope that this project might give the government meaningful criteria for the identification and protection of additional migratory shorebird areas that are significant at the national level.

Sites of international significance have been identified using criteria adopted in the 1971 RAMSAR convention.  These criteria include:  1) a wetland should be considered internationally important if it regularly supports 20,000 or more water birds, and 2) a wetland should be considered as internationally significant if it regularly supports 1% of the individuals in a population of one species of water bird.

In recent analysis, the best available data were used to examine the effect of lowering these thresholds, and results show lower thresholds identified more shorebird areas, which held more birds.

These results suggested that a precautionary approach of using a combination of two criterion thresholds to identify migratory shorebird areas of national significance would ensure that incidental loss of important shorebird areas would be avoided for many species.

The two recommended national criteria identified are:  1) a threshold of 0.1% of a species flyway population to identify nationally significant shorebird areas, and 2) a total abundance of 2,000 migratory shorebirds to identify nationally significant shorebird areas (especially useful when species identification data are not available, such as data collected during aerial surveys).