We had a new paper out this week that I’m very excited about. This paper, headed by Ruth Thurstan, is the result of a symposium at the 2014 International Marine Conservation Congress in Scotland focusing on Historical Ecology. This is a field that I’ve been thinking a lot about, including running a class on it in the spring semester of 2015, and I’m convinced that this avenue of research has real and tangible benefits to ecologists and conservation biologists of all stripes.
Our paper, entitled “Filling historical data gaps to foster solutions in marine conservation” was published, open access, in Ocean & Coastal Management and broadly looks at how historical ecological approaches can inform many aspects of marine conservation.
Historical Ecology in general uses data from non-traditional sources to help us understand what environmental and perturbations occurred before the start of collection of formal scientific data. These perturbations could be manifested at population, community or ecosystem scales and the point of historical ecological studies are to find out what reverberations are still felt in today’s ecosystems.
While our paper focuses strictly on marine themes, there is a rich literature of historical ecological work in terrestrial settings (see a paper which I was involved with lead by Loren McClenachan here for a broader treatment). We wanted to focus strictly on marine systems for this paper in order to keep it to a reasonable length, and to be able to dive into the specifics of a particular system.
One question I get a lot when I talk about historical ecology “who cares what happened in the past, we’re more focused on the future!” It’s a valid point, but I would argue that having a rich knowledge of the historical ecology of a region provides several benefits to conservation biologists.
- It helps us set baselines for restoration
- It allows us create metrics for long term monitoring
- It provides us evidence to challenge long held paradigms
- It gives us a framework to evaluate cumulative stresses
Baselines for conservation: If we do not know what a system looked like in the past, it is reasonable to argue that we are going to have a hard time setting our conservation targets for the future. This aspect of historical ecology is the one that resonates most with me, as it’s all about not setting our conservation bar too low. Yes we are never going to be able to go back to the good old days (and one can reasonably argue that this is a simplistic, non-dynamic view of ecosystems in the first place), but if we can present a first approximation of what ecosystems used to look like we can set up a target for where we would like to go.
Metrics for monitoring: This facet of historical ecology focuses on understanding how much change a
system has undergone, and providing an adequate system of ecosystem characteristics by which to track change. For example Dulvy et al. talk about how sawfish, one of the most endangered groups of fishes in the world, are evaluated by the IUCN. Current IUCN metrics evaluate a species over the past 10 years or three generations, which ever is greater. Sawfish, were essentially hammered by a variety of anthropogenic focuses more than three generations ago, so that by the time the IUCN got around to looking at their populations, the damage had been done. Thus, for example if we saw that there was a doubling of sawfish populations over the past 5 years (which in NO way accurately reflects the trend – seriously these things are kind of screwed) we might be tempted to think that sawfishes are on their way out of the woods. But with the addition of historical data we know that our initial population assessment represents only a tiny fraction of the historical population size, measuring population growth against this historical data indicates we have a long way to go towards restoring these populations.
Challenging paradigms: I’ll have a lot more to write about Caribbean Monk Seals once a paper in press seesthe light of day, but suffice it to say there is a belief that these populations were on their way out prior to Western colonization of the Caribbean. New data that a group I am part of, however has shown that the levels of monk seal exploitation among the British colonies in the Caribbean supports the hypotheses that 1) they were numerous and 2) they were heavily targeted at unsustainable levels. By adding this historical perspective to our view of what a 17th century Caribbean reef looked like we can more adequately frame a centuries long story of resource use and overuse in those waters.
Cumulative stresses: Our understanding of rapid shifts in ecosystem characteristics has been developed over the past decades through watching phase shifts in many reefs around the world. There appears to be a tipping point past which these reef systems move from being coral dominated to algal dominated. A historical ecological approach to reef management helps explain the underlying factors which fuel these rapid and dramatic change. Rather than being the introduction of a specific stress (loss of urchins, changes in water temperature, cyclones etc.) many of the changes in reefs had historical antecedents, in some cases stretching back centuries. For example, Roff et al. show how centuries of upland development and nutrient loading by Queensland farmers lead to the conditions by which a single event (a series of cyclones) created a sudden phase shift in coral coverage. Yes, the storm did the tipping, but the agricultural practices upriver primed the pump. Without looking at this from a historical perspective we are unable to differentiate between proximal and ultimate causes.
I’m really excited about this paper. A solid review paper can introduce a topic to a wide audience, and I am honored to be on the august list of authors. I think doing historical ecological work is an exciting avenue for my lab to take on and I hope we made our case here that in order to think about preserving where ecosystems in the future, it’s important to understanding where those ecosystems were in the past.