h4. Boys outweigh girls
Researchers hope a group of bachelor platypuses living in the upper Wimmera catchment will eventually spread out, establish new territories and find female companions to consolidate a regional population. A study team, monitoring a fragile platypus population in the MacKenzie River, this week captured two ‘new’ male individuals. The find took the ‘counted’ population in the three-year study area to four males and one female.
Wimmera Catchment Management Authority monitoring officer Mark Toomey said the imbalance between males and females in the study area were unlikely to continue. “Males are territorial and tend to move around to find their own patch. The hope is that conditions have improved enough to support their spread across the district,” he said.
Wimmera CMA is contracting the Centre for Environmental Stress and Adaptation Research to run the trapping survey. CESAR researchers captured three platypuses, including an individual they had identified in earlier surveys on Tuesday night. They failed to capture any more specimens in follow-up trapping the next day. CESAR’s capture of the female in April raised hopes the iconic species, feared on the brink of ‘localised’ extinction, might have a chance to recover. But Mr Toomey said the message from the research team, while more positive than in the past, was that the platypus population was still at risk. “This is due to a restricted habitat,” he said.
Extensive trapping surveys have been in the stretch of river upstream of Laharum near MacKenzie Falls. They have coincided with Wimmera CMA’s MacKenzie River environmental watering program downstream of the monitoring area. The water release, from December last year to May, mimicked a spasmodic summer-autumn river-flow regime. The release was designed to provide respite for an important environmental refuge area, home to a broad cross-section of environmental life under stress from the drought.
Mr Toomey said the watering program would help consolidate healthy aspects of the river and the vast network of life supporting high-level predators including the platypus. The threat to the Mackenzie River’s platypus captured widespread media attention last year and emphasised how much impact the drought was having on regional waterways.
This winter again the CMA in partnership with other environmental groups, including the Victorian National Parks Association, is conducting tree planting weekends in our area – see calendar.