I saw a film last night called Lords of Nature: Life in a Land of Great Predators, which demonstrated that the elimination of great predators can have vast effects on their ecosystems. Predators in general have been run out of the lower 48 states; in particular, the absence of the wolf in places like Yellowstone National Park, Minnesota, and Wisconsin has had surprising effects on the forests they used to stalk. The basic argument in the case of wolves is this: wolves prey on deer and elk, whose foraging stunts the growth of new forest flora, leading to tree decline and thus struggles for lower species and the landscape itself.
The filmmakers pointed to a number of examples, including Yellowstone and Zion National Park in Utah where tourist fears of wolves led to their expulsion from these areas and thus to the decline of the overall ecosystem. Wolf reintroduction has been successful in restoring the ecosystems. Thus, the next frontier for wolf reintroduction are areas where human conflict is more direct- with cattle ranchers in the West and sheep herders in the North. However, concerted efforts among government agencies, NGOs, and even Deer Hunter Associations have allowed successful cohabitation of domesticated livestock and wild predators. Targetted herding can ensure that wolves primarily prey on the overpopulated deer and elk, and not on valuable livestock.
Of course, the buildup to the predators’ decline was decidedly human. Shortsighted interventions aimed to protect “assets” and maximize profits led to the one-sided demonization of particular species. Forgive me if I’m reaching as I argue this case is an example of capitalism’s unilateral drive for profit and ignorance of their long-term folly.
A not dissimilar thing is happening with bee colonies- the New York Times has an article about the collapse of wild bee populations and the failure of domesticated beehive increases to compensate. The problem isn’t necessary bee collapse itself- it’s that humans are asking too much of them.
This wouldn’t mean the end of human existence, but if we want to continue eating foods like apples and avocados, we need to understand that bees and other pollinators can’t keep up with the current growth in production of these foods.
The reason is that fruit and seed crops that are most dependent on pollinators yield relatively little food per acre, and therefore take up an inordinate, and increasing, amount of land. The fraction of agriculture dependent on pollination has increased by 300 percent in half a century.
What happens when lands are converted for crops? Wild bee populations decline:
The paradox is that our demand for these foods endangers the wild bees that help make their cultivation possible. The expansion of farmland destroys wild bees’ nesting sites and also wipes out the wildflowers that the bees depend on when food crops aren’t in blossom. Researchers in Britain and the Netherlands have found that the diversity of wild bee species in most regions in those countries has declined since 1980.
Human replacement of wild bee populations can only go so far, and it cannot replace the biodiversity necessary to sustain an ecosystem. Of course, this aspect was present in Lords of Nature as well. The presence of great predators does not just favor certain types of flora in a zero sum-game; it also forces the rapid evolution and adaptation of fauna, creating a bevy of biodiversity. Try as we may, we’ll never be able to put a value on this biodiversity. As these episodes point out, ecosystems are complex, and it’s very arrogant for humans to assume that simple valuation will preclude unintended consequences.
Reducing human impact on nature is a good in and of itself. It may mean sacrifices as well:
If we want to continue to enjoy almonds, apples and avocados, we have to cultivate fewer of them, more sustainably, and protect the wild bees that help make their production possible.
Similarly with the predators, we may have to be willing to pay more for livestock goods and consume less, as further predator reintroduction will result in losses. However, the benefits that come from these sacrifices appears to compound over time, so it’s necessary that we not underestimate the value of nature.