How do you measure whether a restoration project worked?
The answer is, typically, you don’t.
Most efforts to plant trees or recover native environments either aren’t followed up by scientists over time, or else they are carried out by practitioners who may not have the time, resources or expertise needed to trace whether a project has been successful.
This means that for many restoration attempts, the survival of seedlings can be pretty low, restoration objectives (if there were any in the first place) are not always met, and ultimately money can end up being misspent.
But how about in the instances where we do track the success of restoration?
If what we’re interested in is the recovery of wildlife (often a stated goal of restoration) then scientists will look at the species within the restored forest and compare this to some counterfactual. In an ideal world, this would involve looking at the species around before and after restoration efforts were implemented. But this takes a fair amount of foresight, so often what usually ends up happening is we’ll compare an area that was restored, say fifteen years ago, to an area nearby that wasn’t.
So you set your dung beetles traps, or swing your butterfly nets, or set your camera traps in:
- A farmland (representative of the area before restoration)
- A regrowing forest (the actually regenerating area).
- An old-growth forest (representative of the the “level” of biodiversity you ultimately want to be working back towards…)
Then, you compare measures of biodiversity between these areas.
You can contrast the number of species (species richness) between different sites, but often this alone is a very, very poor measure of whether restoration has been successful. This is because the number of species tells you nothing about how abundant those species are, or whether restoration has helped to recover the populations of wildlife you might care about most; say forest-specialist species, or rare, endangered or endemic flora and fauna.
But even when we do dig in to the population sizes and identies of species within recovering forests, the truth is that almost universally, measurements of restoration success so far have been awfully species-centric. We focus on what’s around, rather than what’s happening.
But ecology is full of complex interactions, mutualisms, competition and top-down and bottom-up interrelationships that ultimately determine whether an ecosystem ticks along properly.
An old-growth forest isn’t just a static bank of wildlife. It is a complicated spool of criss-crossing interactions, chockerblock with links. Links between plants and pollinators, between seeds and seed dispersers, between fungi and plant roots, prey and predators, between herbivores and leaves, dung beetles and dung, microbes and soils and parasites and hosts. Links and dashes.
So when we are looking at whether restoration efforts have been successful only through the lens of species, we are only ever looking at the dots. But really, we want to know about the return of complexity; we want to known about the restoration of dots and dashes.
RELATED ARTICLES:
