For many years, scientists and others have been talking about the problems of using HRV and reference conditions as management targets. Jon and I have had many mind-numbing discussions about it (as placed in the 2012 Planning Rule) on this very blog. So I thought on Science Friday, I’d start exploring the work of other scientists who have expressed concerns about this. Sadly for me the 2012 Rule is water under the bridge, but the Feinstein bill is not. Let’s see how that bill talks about using reference conditions in the large landscape projects:
“2) evaluates ecological integrity and reference conditions for the landscape;
3) identifies areas that have departed from reference conditions;
4) identifies criteria for determining appropriate restoration treatments;
5) are based on the best available scientific information, including, where applicable, high-resolution imagery and LiDAR; and
6) identifies priority restoration strategies.
o Restoration actions shall 1) emphasize the reintroduction of characteristic fire; 2) for any proposed mechanical treatments, seek to restore reference conditions and the establishment..
Now, you don’t need a Ph.D. in vegetation ecology (or plant evolution, or wildlife biology) to suggest that restoring (say, American Chestnut) may be difficult or impossible to achieve due to a) other changes that have happened since, like other species having taken over b) climate change, c) invasive species, d) human population impacts (pollution, domestic animals and pets and so on) e) lack of Native American practices and so on. So why does this idea have such a hold on the imagination? Why has it been argued that this is a more “scientific” approach, when many scientists disagree? And while we can discuss that reference conditions aren’t HRV, well, then aren’t they just conditions that some group finds desirable, and not any more “scientific” than any other conditions?
This article is by Dr. Connie Millar of the Pacific Southwest Research Station, and she uses her climate studies to come up with a different conclusion about what to do- not exactly what many mean by “restoration” but helping systems/organisms be resilient and adapt to future change. It seems like a very different, and possibly more realistic and less expensive, paradigm (to me). The paper also includes a history of the concept as used in forest management on page s30. Here are a few quotes:
From the standpoint of this review, I focus on an underlying assumption of stationarity that continues to emerge in the HRV literature even where discussions address historic variability. Further, two elements in the discussion of HRV remain unconfronted and problematic: First, what historic time period is most relevant to current and future conditions (and, in contrast, what periods are inappropriate); and second, whether “approximating historic conditions” of any historic time period is a wise approach to managing for functional ecosystems of the future
I agree that the latter deserves much more discussion. Especially since it could be argued that generalized “restoration to reference conditions” is a “nice to have” and strategic fuel treatments are a “need to have”; I’d put my tax dollars on the latter rather than the former.
For the many ecosystems not severely degraded, historically informed strategies focus on (a) removing barriers that impede inherent ecological capacities to respond to change, and (b) assisting species and communities to transform in ways most compatible with their inherent capacities and with social goals. In regard to the first, we learn from historic retrospect that the truly novel conditions at present and increasing in the future are not so much about the magnitude or even pace of climate change, rather the overwhelming transformation modern humans have imposed on Earth. The Anthropocene era (Ruddiman, 2003) is characterized by nonanalog conditions for species survival, and the accelerated pace of extinction shows that many species have not been able to use their inherent capacities to respond to change in the face of such barriers. Functional restoration thus can emphasize, to the extent possible, removal or mitigation of impacting barriers derived from land development; fragmentation; air, land, and water pollution and contamination—carbon dioxide being among the worst offenders; land-use changes, invasive species, and many others (Millar, Stephenson, & Stephens, 2007).
Assisting ecosystems to transform in ways most compatible with their inherent capacities involves exploiting species tendencies to move geographically and to adapt genetically in the face of change. In regard to the former, if barriers to dispersal cannot effectively be removed, assisted translocation, either of species beyond their current range limits or of genotypes beyond their current provenances, might be effective. Understanding changes that are already underway will enable restorationists to ease transitions to future states, often with less extreme variability or outcomes than socially tolerable. Assisting genetic adaptation can occur in many ways informed by natural selection—such as experimenting with seed diversity in restoration mixes, taking advantage of the significant opportunities that insect-mediated mortality events can have to ratchet population adaptedness forward, and setting goals at bioregional not local scales.
While much can be learned from reconstructions of historic responses to climate change, and especially from historic periods similar to what might be expected in the future (e.g., the Medieval interval or the middle Holocene), historic conditions generally, and especially those from nonanalogous historic periods (such as the Little Ice Age) make inappropriate reference conditions for the future. In such a case, target and goal setting for functional restoration must pioneer additional approaches. The return to more utilitarian goals and targets recognizes both the reality of the Anthropocene and that resource-management has, in fact, always been a human-directed and conceived endeavor. Emphasis on ecosystem services—including essential utilitarian functions such as clean air and water, landscapes for recreation, production of fiber and meat, and sustenance of biodiversity desired by humans and provided by healthy ecosystems—will guide the next generation of management strategies. Achieving these goals will be greatly benefited by historically, as well as ecologically informed management.