Walker Swamp photos highlight the challenge of ‘Shifting Baselines’ in ecology

The surprisingly rapid and ongoing changes at NGT’s Walker Swamp Restoration Reserve witnessed over the last six years have been highlighted by the collection of a set of photo points across the reserve. In case you’re wondering, a photo point is a fixed location where a comparative photo is taken at a specific interval – often annually.

Following the recent bushfire across our Reserve at Walker Swamp, south of Lynchs Crossing Road, I revisited the photo points for the area affected by fire. In placing the recent photos next to previous shots I have been amazed by the extent and complexity of change that events over the last few years have produced (e.g. Figure 1 below).

Blue gum removal, wetland restoration, a major flood event, a sustained dry period and then the recent bushfire have together markedly changed the swamp and the surrounding landscape.

As an ecologist, I have spent the last 30 years giving talks to communities endeavouring to describe the extent to which the environment in which we live has changed – and the ongoing and dramatic consequences for the composition and relative abundance of the plant and animal communities that remain. One of the key challenges has always been the accurate painting of a picture of Australia prior to European colonisation, describing just how much has changed and developing in everyone a sense of why natural ecological communities are struggling now, even in places like the Grampians/Gariwerd National Park. While for many people, the Grampians may appear natural/unchanged, the gradual, or stepped, but ongoing change over time has seen the loss of many species and the changing of communities. Importantly hidden within that gradual change is what we call an ‘extinction debt’ that will continue to be witnessed by generations to come.

For example, in 1981 I watched a family of five eastern barred bandicoots in the Victoria Valley – perhaps some of the last in the valley at that time. Their presence in the Grampians represents an important component of the natural fauna for me and those of earlier generations. Sadly, this is no longer true for younger generations. The reference set of plants and animals that I can recall from my early twenties, as a personal ‘baseline’ for the region, is no longer present. With ongoing global and regional deterioration in the natural environment, our baseline standards and expectations for environmental health continue to decline. This represents an enormous challenge for the conservation, restoration and management of that environment.

Shifting baseline syndrome (SBS) or “environmental generational amnesia” is a psychological and sociological phenomenon whereby each new human generation accepts as natural or normal the prevailing environmental conditions in which it was raised. SBS describes a gradual change in the accepted norms for the condition of the natural environment due to a lack of human experience, memory and/or knowledge of its past condition. With ongoing local, regional and global deterioration in the natural environment, this results in a continued lowering of people’s accepted norms for these environmental conditions. Unfortunately, the evidence for this syndrome is now being documented across the world in both the oceans and terrestrial environments (and we’ve also discussed it previously in the NGT newsletter). In a rural village in Yorkshire, UK, Papworth et al. (2009) found that younger residents, compared to older ones, were less aware of changes in the abundance of common bird species over the past 20 years. In Australia, I suspect that most would not realise that our bird population has also declined dramatically in the last 30 years.

The fundamental driver of SBS is the lack, or paucity, of relevant historical data on the natural environment. Having seen the dramatic changes at Walker Swamp evidenced through the photo points, I am now beginning to understand why SBS can be so marked over very short periods of time. This particular site also highlights just how important NGT’s environmental restoration work is for setting our ecosystems on a long-term trajectory of recovery. After all, the wetlands of Walker Swamp, which can now fill again and attract wildlife, had not been seen in this revitalised state by a generation of elderly locals throughout their entire lifetime, until NGT reversed artificial drainage and restored this area in 2019.

You can access the pdf document of photo points here or by clicking the image below:

References:
Papworth, S. K., Rist, J., Coad, L., & Milner-Gulland, E. J. (2009) Evidence for shifting baseline syndrome in conservation. Conservation Letters, 2, 93-100. doi: 110.1111/j.1755-1263X.2009.00049.x.