So the new official species name Sousa sahulensis has supplied me with sibilant alliterative opportunities, but has also changed the nature of the research we’re doing here on the North West Cape. There has been some research done on Indo-Pacific humpback dolphins, but the humpback dolphins that live their lives around the continent of Australia (and maybe Papua New Guinea?) may have less in common with their relatives than we had previously thought.
According to Science News (shame on me for not reading the actual paper yet…), skull morphology and DNA sequencing were used to determine the separation of S. sahulensis from their northern cousins, S. chinensis. Our dolphins cannot cross Wallace’s Line, a deep ocean barrier separating Australia from the rest of the world and, incidentally, explaining in part why Australia and its waters contain so many endemic (local only) species- as the Line formed, these coastal dolphins could no longer cross between the home waters of S. chinensis and the Australian continental shelf. Those on the southern side of the barrier evolved through genetic drift and natural selection such that they are significantly different from the northern side, and have now been recognized as their own unique group. But why does that matter?
Well, first of all Tim has to change all the abbreviations we’ve been using on spreadsheets (Sc to Ss) and the title of his PhD…
Okay, the real reason why it matters is that, having proven significantly different from their relatives Up Above, S. sahulensis is now virtually unknown. We can’t assume they behave the same, use space in the same way, or require the same resources or protection as S. chinensis, nor can we rely on the larger population size of both species combined to buffer any human-caused losses or stresses. As oil, gas, and mining operations descend upon Australia’s coastal waters, coral reefs begin to feel the impacts of global climate change, and fishing and ocean recreation continue to increase, we need as much knowledge as we can get about these animals. Their impact on coral reefs and surrounding ecosystems could be a key part of healthy seas around Australia, and we don’t even have a good population estimate, nor any indication of whether the population is growing, shrinking, or neither. Tim’s working hard to break open the wealth of information that the North West Cape dolphins have to offer, but they’re elusive and research requires a lot of time and patience.
Much has been written about the importance of coral reefs for economic and environmental reasons, and much has been written about wildlife in general having inherent importance to humanity. I support all those reasons, and can give you pages and pages of arguments on why it’s important to maintain diverse and stable ecosystems of all types. However, I also think simply that we humans, as a species (yes, one global and multiplying species), ought to tread lightly on the world.
Yes, it’s important to understand and preserve the world around us because without diversity we and our world will be more easily overcome by change, because reefs and mangroves and wetlands provide storm shelter and water filtration to human habitations, because icy tundras and redwood forests and tigers and whales and tiny colorful fishes inspire us and make us wonder. But that all presupposes that it’s our right to choose to destroy or save those wonderful things. We approach the world assuming that we can manipulate it at will, but we are just students of systems much larger and more complex than the ones we have created.