A thread: I am SO HAPPY to announce that our paper on #Restoration and Recovery of Earth's Damaged Ecosystems is out in @royalsociety Proceedings B! rspb.royalsocietypublishing.org/content/285/18… We are in the process of making it #openaccess but HMU if you want a PDF.
It has already received some media coverage and I'll try to keep this thread updated with more. Here's the first story: chicagotribune.com/news/ct-met-ec…
I am extremely proud of this work. I have been building a database of studies that look at restoration/recovery for nearly 10 YEARS now. And I got to work with amazing co-authors @josemreybenayas @KDHoll5 @iheartnitrogen and other non-tweeps.
But the work itself is likely to be a bit controversial so I want to detail what we found, what it means, and what it doesn't. We collated ecosystem response to the cessation of large-scale disturbances like agriculture, logging, oil spills, and eutrophication.
We found 400 studies that had to have both a restoration target (most often an undisturbed site nearby and sometimes a historical reference) and over 5000 response variables - stuff people measure to understand ecosystem response.
We noted whether these ecosystems were let to recover on their own after the disturbance ended or whether active restoration - like planting trees, stabilizing river banks, etc was used.
Oops - one more criteria for study inclusion I forgot to mention. Studies had to measure recovery at two points in time after the disturbance ended so that we could measure recovery rates.
What we found was glass half full/half empty. The good news is that recovery rates were positive in all cases when data were collated by ecosystem, disturbance, metric type, and organism type. So ecosystems are recovering their function and biodiversity after disturbance!
The bad news is we didn't find full recovery and that recovery rates slow down with time since the disturbance ended. So what this means is that while ecosystems are getting better, the last stages of recovery are hardest and we don't see complete recovery often.
We also compared how close to recovery and how fast recovery was in passively recovering and actively restored systems. Here's what's likely to be most surprising - we found restored ecosystems recovered at the same rates and at the same levels of passively recovering systems.
So, on the whole, over all the studies throughout the world, actively restored systems aren't recovering faster or more completely than systems left to recover on their own.
I want to make really clear that this finding does not mean we should give up or not invest in #restoration!!! It means we need to be more strategic about where we restore to maximize the benefits. I'll go through a couple caveats of the findings later in the thread.
Restored systems are still recovering through time and they are still gaining back biodiversity and functioning, which is awesome! And restored systems often have much broader goals than speeding up recovery or exacting more complete recovery than passively recovering systems.
They may have specific socioeconomic goals, or may be looking to create habitat corridors, etc., and aren't being set up so that they outperform systems that might be recovering on their own.
Just to be clear, when I first saw the active vs passive results I did not believe them. In fact, I've spent the better part of a couple years looking at the data in different ways to try to see what was going on.
So, let's walk through a couple of ideas we had about why we saw that, and some caveats. First, maybe managers are really good at choosing the sites that need restored and aren't recovering on their own.
That would mean that we see a site not recovering, restore it, and then the restored site is recovering faster/more completely than it was before we restored it, but still at the same rate as a site not being actively restored because we knew it didn't need extra help.
This is entirely possible and not necessarily something we can test with our data (we didn't look at restored sites compared to their degraded states; we compared active vs passive).
We did test for whether actively restored systems were more disturbed than passively recovering systems (not the same question but related), and found them to be equally disturbed after the disturbance ended.
Another potential reason we saw what we saw is that the studies we looked at were too apples and oranges. Passive recovery in a boreal forest might not be comparable to active restoration in a tropical forest following logging, for example.
But we did the same analysis on the subset of studies that measured responses to the same disturbance in the same ecosystem in the same study and we find the same patterns.
But there were only 16 studies that did those comparisons which underscores the need for WAY more studies which compare the two directly in the same study!!!
We explored if actively restored sites had less time to recover and we did find that restored sites had three or fewer years to recover on average, which could play a role in our results.
However, I don't think that it can explain how consistently we find active restoration not to have an added benefit of faster/more complete recovery than passively recovering systems.
Just to be clear - there are ecosystems that ABSOLUTELY REQUIRE restoration. An example is @Nachusa and other prairies restored from farms. If we didn't plant seed, burn, etc., we would get a field of weeds after farming.
So our data don't capture situations like those because you'd never have someone compare letting prairies come back on their own to actively restoring them. There were some prairies in our database, but they all would have been coded actively restored.
So, where does that leave us and #restoration? 1. Restoration is still a critical tool to reverse the biodiversity crisis. We need to figure out how to do it most effectively.
We call for more investment into restoration and emphasize we need government and industry partnerships with local communities and stakeholders to better understand where restoration can provide added benefit.
We suggest that in systems where it's unclear whether restoration provides extra benefits beyond letting ecosystems recover on their own, that people consider letting ecosystems passively recover for a few years and restore if needed.
Lastly, if restoration is initiated and it makes sense to do so, passive recovery should be compared to active restoration to help us understand better where #restoration has the biggest potential to help.
#Restoration ecology is at a crossroads. We can/should continue documenting ecosystem response to disturbance but we also need to take a step back and design restoration to better ask where/when restoration is most effective. /End
More media coverage: newsroom.niu.edu/2018/02/28/fix…
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