It is a great privilege to work on the BC Central Coast. The human history and culture are some of the longest in North America, and some of the most continuous, despite traumatic disruptions in the past 150 years. Ecologically, the very wet hypermaritime where I work rivals tropical rainforests for annual precipitation and has some of the strongest links between marine and land-based ecosystems on the planet. It is a mosaic of habitats, from temperate rainforest to deep peat bogs.
My focus is on transitions. Ecosystem types can transition from one to another given the right push: with too much water, sedge-bog can accumulate moss and become peat bog; with too little water, it can transition to grasslands or even forests as time progresses. A big, sudden transition from one type of ecosystem to another is often called ecological collapse, and the point at which collapse occurs is known as the threshold point (tipping point, critical point, etc). Managers are justifiably worried about threshold points. They represent really fundamental changes in ecosystems that are hard to reverse. The problem is that we often don’t know when an ecosystem is about to cross a threshold, so it’s difficult to manage for them.
In my work on the central coast, I’m trying to pick up a signal of an approaching threshold point. Researchers have strong reason to think that as an ecosystem creeps towards collapse, it starts to show signs. In particular, ecosystems bounce back from disturbances a little more slowly when they are approaching a threshold than if they do when they are totally healthy and intact. So I’m moving bits of sedge-bog towards a transition to grassland by changing the hydrology. In real terms, that means I picked up pieces of bog and put it on top of rocks in a bucket. Then I kicked my plots, literally, 300 times each with a rubber boot full of concrete.
Now I’m tracking how sedge-bog recovers, both when it’s still on the ground and happily connected to the water table, and when I’ve lifted it above the water table. If recovery is slower in the bucket-bog, it may offer a (relatively) easy-to-implement tool for monitoring the approach of threshold points in managed ecosystems.