We know that humans are a dominant force shaping the planet, but there’s a debate over whether this really constitutes a new geologic epoch, the Anthropocene. For now, let’s leave this debate aside and focus on a practical question: for conservation biologists, do the ideas of the Anthropocene give us any insights into the types of conservation projects we should pursue?
One of the core ideas of the Anthropocene is that we live in a matrix of human impacts that are extensive and far-reaching. There is no “wilderness” any more, only landscapes impacted to varying degrees by humans. The implications of this for practicing ecologists are nicely summed up by Ellis:
To advance the science of ecology in an increasingly anthropogenic biosphere, it is useful to begin with “The First Law of the Anthropocene”: the ecological patterns, processes and dynamics of the present day, deep past and foreseeable future are shaped by human societies (p. 316).
Modern conservation practitioners choose their projects from a diverse portfolio of strategies. Two weeks ago, Kiza wrote about assisted colonization, which is the strategy of deliberately moving a species to a new habitat when global change renders existing habitats uninhabitable. A related idea is the “rewilding” movement, which is the restoration of an ecosystem through the re-introduction of extirpated species (Nogues-Bravo et al. 2016). Conservation biologists also think hard about optimal siting of nature preserves, environmental restoration aimed at mitigating certain high-profile stressors (like invasive species or toxic chemicals), and best strategies for minimizing the impacts of land use change. In many large ecosystems, conservation projects are selected by a diverse group of actors in agencies and NGOs pursuing several of these strategies at the same time.
Though all of these conservation actions can be valuable, it isn’t easy to measure the benefit of a particular project. For example, how much “benefit” might accrue to an ecosystem following the removal of an invasive species? Would another conservation action, like remediation of toxic contaminants, give a greater ecosystem benefit per dollar spent? This question matters, because conservation projects have opportunity costs associated with other, forgone projects. In lieu of real measurements of the cost-effectiveness of categorically different conservation projects we must rely on our own judgment to decide what types of projects to pursue. This opens the door for cognitive biases in the way we value certain types of conservation actions. For example, does the creation of a nature preserve or a national park seem like a greater conservation accomplishment than large-scale remediation of contaminated soils? Do we as conservation practitioners have a bias toward valuing conservation actions focused on “wilderness” more than conservation investments directed at human-dominated landscapes?
Let’s look at an example of a conservation strategy that might be the poster child for conservation in the Anthropocene: retrofitting road culverts and removing dams to restore the movement of migratory fishes. Road culverts and dams are by far the most common structures in our rivers and streams: in the United States, we have upwards of 4 million of them. Nearly every river flows through thousands of these structures on its journey from headwaters to mouth. In-stream barriers such as road culverts and dams block the movements of migratory fishes, disrupting breeding migrations and fragmenting freshwater habitats into a mosaic of isolated patches. Habitat fragmentation of this sort is a leading cause of declining freshwater biodiversity and ecosystem services worldwide. In much of the US and elsewhere there is growing investment in restoring ecosystem connectivity by retrofitting road culverts and removing obsolete dams.
Retrofitting road culverts and removing dams to restore fish migrations are quintessentially Anthropocene conservation actions, because these conservation investments are targeted at human-dominated landscapes. When we retrofit road culverts, we’re enabling fish to navigate through a matrix of societal infrastructure to reach historical breeding grounds. Not much wilderness is involved! Though these conservation projects occur in human-dominated landscapes, they can be incredibly cost-effective. For example, careful prioritization of barrier removals in Great Lakes tributaries could lead to a doubling of the amount of accessible fish habitat in the entire basin for a mere $70 million (Neeson et al. 2015). How many other conservation actions might have this return-on-investment? Would the same $70 million be better spent on purchasing land and setting aside nature preserves in a relatively pristine portion of the Great Lakes basin? As a point of comparison, the ongoing Great Lakes Restoration Initiative has spent nearly $1.6 billion on a wide range of restoration projects since 2010, but outcomes assessments are ongoing (GLRI 2014).
So, does Ellis’ First Law of the Anthropocene make a difference for practicing conservation biologists? Maybe it is worth reflecting on the biases we may have in the way that we value different types of conservation actions, and whether ideas from the Anthropocene might shape our valuation of conservation projects in human-dominated landscapes.