Our last big field trips together in Australia were to the Fleurieu Peninsula, south of Adelaide. On the first day out we were lucky enough to be toured around by a senior aquatic ecologist, hydrogeologist, and an ecologist turned water planner with the South Australia Department of Environment, Water and Natural Resources. The second day we visited a different swamp with Tim Vale, a Habitat Protection Officer with Conservation Council South Australia, a conservation group based in Adelaide. Tim took us into the “guts of the swamp where everything interesting is” at Stipiturus Conservation Park, named after the critically endangered Mount Lofty Ranges southern emu-wren (Stipiturus malachurus intermedius), which makes its home in the dense thickets of the Fleurieu Peninsula swamps.
The first day we got the lay of the land and learned that many of the watercourses on the east side of the Mount Lofty Ranges were once dominated by freshwater swamp habitat extending from the crest of the mountains down to the coast. Fleurieu Peninsula swamps seem to be the equivalent of cienegas in the southwestern United States and have experienced a fate very similar to our cienegas, since humans on all continents find it hard to farm and make homes in swamps. Little did they know swamps make important contributions to water quality and quantity. Humans have really stuffed it up, as they say in Australia, when it comes to managing wetland ecosystems in the name of progress.
Most of the Fleurieu Peninsula swamps were cleared by hand and drained through elaborate systems of ditches. They continue to suffer from threats very similar to our springs and streams in southern Arizona, including destruction by livestock and human exploitation, pumping of nearby groundwater, and changes in recharge of groundwater due to dams and other infrastructure in catchments (watersheds).
Fleurieu Peninsula swamps are listed as a critically endangered ecological community under the Australian government’s Environment Protection and Biodiversity Conservation Act 1999. According to Conservation Council,
This listing recognises that the long-term survival of the Fleurieu Peninsula swamps is vulnerable to ongoing threats, particularly due to the small patch sizes of the remaining swamps.
We visited this lovely remnant swamp on a piece of property owned and cared for by the Mount Compass Elementary School:
We saw lots of superb fairy-wrens (“superb” being a very appropriate part of this beautiful bird’s common name) and heard at least one swamp rat scuttling through the thick brush at this site, but saw no sign of the emu-wrens. Not that we were likely to see them through the dense vegetation of ferns, juncus and tea tree.
Threats to remaining swamps also include human land uses such as this large plot of commercial forestry just across the road from the Mount Compass School swamp:
A good portion of our tour was spent chatting about the Eastern Mount Lofty Ranges Water Allocation Plan which covers the Fleurieu Peninsula. Some of the more interesting aspects of the plan include requirements to maintain low flow in the streams below dams in the event of drought, buffer zones that preclude drilling of new wells around groundwater dependent ecosystems, and a really awesome map of perennial stretches of streams and springs! There was great care and consideration given to the amount of water allocated to these types of ecosystems, as well as the timing of water availability to support ecosystem function and the life cycle of resident species. And finally, there was the exciting news of a new system in which water allocations will not be a set annual amount, but rather fluctuate based on a rolling average of available water (think variable precipitation). I don’t envy the modelers that have to make that call, but the concept makes very good sense. Quote of the day from the car conversation:
It’s a bit of a gray world, water planning.
Yeah, as in, it makes your hair go gray!
On the second day Tim took us to Stipiturus Conservation Park and we broke out the gumboots and binoculars.
As we walked around the edges of the swamp, Tim pointed out a variety of restoration works to install native plants and recreate habitat that had previously been cleared.
He also pointed out the results of a recent controlled burn set in an effort to re-introduce disturbance into the swamp and diversify vegetation structure.
The highly endangered Mount Lofty Ranges subspecies of the southern emu-wren nests in this swamp, but it is estimated that there are only 4-5 breeding pairs hanging on here. We spent a fair bit of time listening and peering into the thick of it, and Randy heard wings fluttering beneath the impenetrable mass of vegetation, but we never actually saw one.
Southern emu-wrens are delicate little birds. They have underdeveloped flight muscles and an almost inaudible high-pitched call. It is thought that their lack of mobility combined with the severe fragmentation of swamp habitat has contributed to their decline.
Gumboots were essential equipment as we explored the depths of the swamp, although they didn’t prevent swamp butt (caused by an irresistible urge to crouch and take photos of very small plants and insects).
Much like Cienegas and springs, Fleurieu swamps provide direct benefits to a diverse array of species that depend on them for habitat while also indirectly benefiting the hydrologic systems of which they are a keystone. It’s a shame that the vast majority of them have been destroyed, but in the twenty-first century their value is becoming clearer, and conservation work is underway to restore as many of them as possible.