As I've written in the past, species are constantly blinking in and out of existence. This may or may not be of concern depending on your scale of interest. After all, extinction is the only real certainty.
Last month Andy Revkin asked, 'Does the world need leatherback turtles? '
Need, eh? Well, maybe he's posing the wrong question... We don't fully understand the ecological role of sea turtles, but we do know their numbers are a shadow of former abundance. Their loss is reflective of a growing global trend: the loss of ocean species through fishing down food webs and incidental bycatch. So many big critters are dwindling as we've altered the slowly evolved colorful diversity of animals living offshore.
Well folks, do we need leatherback turtles? Arguably, no. However, as J. Nichols responded, 'each lost species weakens us all, but the loss of sea turtles goes far deeper than the loss of a single thread in the fabric of life.'
- Log in to post comments
'each lost species weakens us all'. It's quite something to think about and ponder. I absolutely agree, and it makes me feel helpless and sad.
Wwo need the Leatherback turtle because they to are part of the "web of life."
Sheril, I think you (and some other commentators) have conflated two views of the Earth and its veneer of living things that I tried carefully to separate on my initial Dot Earth post and lots of followup exchanges.
One is the functioning biosphere, which appears to derive its resilience -- in the face of countless assaults by everything from volcanoes to asteroids to humans -- not from individual species, including leatherbacks, but from the web of diversity out there. That is the "world" I was posing the question about. That world clearly doesn't "need" any particular species.
The full post went on to ask whether we humans (the human world) want to have a planet with a rich array of life forms later this century? That is the question I think most people would answer with a resounding "yes."
Revkin's response to the first posting on his site indicates his purpose for posing the question:
I think that Revkin largely misses the mark. Sure, there is a choice, but the real choice we have is not about whether individual species "make the cut". And if we approach the issue from that direction, we are bound to fail -- miserably.
The most important choice we have is whether we are going to preserve the ocean and other habitats in a state that will support future generations -- non-human and human alike.
It is at least possible that something more than just overfishing (or even building on sea turtle nesting beaches) is killing sea turtles. For all we know, the sea turtle demise may be an indicator of something far more insidious -- ocean acidification, for example.
When you look at it in terms of habitat preservation, the survival of species like the sea turtle becomes inextricably bound with our own.
There is obviously no way that we are going to save every plant and animal that faces extinction. Nor should we even try. But choosing the species to devote our limited resources to is most certainly not the optimal approach. In fact, it may be the least optimal.
We'll ask this question again. And again. And again. And curiously, each time, it will seem that there is no clear, unambiguous reason we 'need' each species about which it is asked. And then, perhaps, we'll find ourselves with a collapsed ecosystem, able to maintain only a fraction of the world's present human population.
No single species is a linchpin. No single species is essential to human existence in its own right. But each one plays its own complex role in the environment we require to survive. As they disappear, one by one, our environment will become less and less resilient, more unpredictable, less able to provide for us.
Andy Revkin:
I do not disagree, and as I wrote earlier, extinction is the only certainty... but I do feel it's important to emphasize that we do not understand what the loss of biodiversity (the sum of so many individual parts) will mean for earth. It's possible that losing the large charismatic marine species will merely result in boring oceans of algae and jellyfish and if so, does that matter? Humans have mailable tastes after all, and we adapt to what industry supplies. A boom in lower trophic level species creates emerging markets and new opportunities to exploit the next readily available critter.
My greatest concern, however, is that we don't know how all of these species interact and each is part of the ecosystem. Sure, a few lost organisms may only result in the loss of some stability while we maintain overall structure. But where is the threshold? Are we at risk of losing resiliency if too many missing components result an alternate state?