Managing for the impacts of multiple anthropogenic factors
Some thoughts on management interventions when systems are affected by a large number of factors
A question I sometimes get after my talk on the effects of multiple concurrent global change factors on ecosystems is about how we can use the information to better inform management. I was also asked that question today at my presentation at the University of Kyoto.
We find that an increasing number of global change factors tends to cause a clear trajectory of decrease in ecosystem functions and properties, and also biodiversity. This is bad news, but how can we use this information to inform management?
I think there are four points:
If this effect is real, and we have plenty of reasons to believe that this pattern with an increasing number of factors is real, since we see it repeatedly in experiments, in the lab and in the field, and also in observational data, then it could mean this: any reduction in the number of factors would probably be beneficial. Perhaps some factors are cheaper to remove, and perhaps this is a good place to start.
Since the number of factors tends to have such a strong effect, perhaps it is interesting to ask what kind of human activities tend to trigger the greatest number of factors? Perhaps it is driving a car: this is related to land use change, carbon dioxide production, salinity (road salt use), tire wear particles, and a number of other drivers. If we can identify such activities that cause the greatest number of changes, perhaps those can become a target for management.
We recently did an experiment that suggests that factors when combined with many factors have completely different effects than when acting alone. This suggests that we need to perhaps look more into this high-dimensional range of effects, and not just rely on the singe-factor information that we tend to have.
And of course: if you can identify a main culprit, then it may make sense to focus on the factor with the highest intensity in a given location; if there is a clear ‘main problem’, then maybe the number of factors is not the most important thing to worry about. Even thought I am not 100% sure about this….
Just some thoughts, and this is also how I answered the question today after the seminar. Do you have any other ideas how this finding about the effects of multiple factors could inform management? We did this work just out of curiosity and didn’t really think about the management implications. But I think it’s a great point to think about. If you have any ideas, please let me know in the comments.
There may be sets of 'good management' practices resulting in bundles of ecosystem services. - Things that you have to change in a coordinated manner, such as changing pesticide and fertiliser usage, as well as possibly irrigation. - 'Good practice' is using balanced/well-coordinated nutrient element and active ingredient compositions (mixtures/cocktails) or temporal or contextual sequences of those.
Editors of my papers that are from Europe tend to ask me why I don’t recommend focusing on the condition of the soil before restoration begins instead of the goal in some of my papers to fine tune the restoration process. I agree with them but this seems to be a cultural divide. In the midwestern US, grassland restoration is largely reclaiming a piece of agricultural ground with various degrees of degradation, keeping it as Ag until ready to disperse seeds, then throwing down a hastily made seed mix and crossing our fingers. I’m curious if anyone here runs into this types of reviews on restoration papers? Is Europe really focused on conditioning the soil before starting plant community restoration?