Distribution and habitat of the critically endangered Capricorn Yellow Chat Epthianura crocea macgregori.

Abstract

The Capricorn Yellow Chat (Meliphagidae: Epthianura crocea macgregori) is a poorly known, endangered passerine of coastal north-eastern Australian wetlands. Recent research has highlighted the need for evidence based management and that recovery programmes may be hampered by a lack of sound ecological knowledge. Capricorn Yellow Chats were found at 15 sites near Rockhampton between Broad Sound and the Fitzroy River delta in the south. Overall, suitable habitat was limited with an area occupied of about 6 000 ha, confirming the need for careful management. Habitat may be typified as grass-sedge wetlands or tall supratidal saltmarshes that are temporarily flooded, with pools becoming brackish to hypersaline as they dry. Over 96% of sightings were on coastal plains formed by marine sedimentation processes, most without current tidal influence, and many less than 5 m above sea level. The remaining 4% were associated with alluvial-formed plains, but only where these bordered existing marine plain sites; suggesting a preference for marine plain habitats, possibly reflecting structural differences and foraging preferences (marine plains tend to be more open due to the presence of salt-tolerant samphire vegetation). Sea level rise was identified as a major threat to the subspecies with chat sightings at most sites averaging less than 2 m above current highest astronomical tidal influence, and sites becoming tidal or with regular storm surge influence under future modest predicted sea level rise scenarios of 0.5 m by 2100. Most sites had some form of banking to reduce tidal influence and promote freshwater pasture grasses for cattle production. The site supporting most chats had small banks that allowed floods to flow around them, maintaining connectivity with the downstream marine systems. This study contributes to baseline information essential to the evaluation of any future management interventions; thus avoiding the pitfalls hampering much of the global conservation efforts directed at threatened species.