Imagine that a “time machine” allowed you to go back in time — back exactly 64,999,995 years ago, just five years before the crash of the meteor that marked the end of the Age of the Dinosaurs. You have just enough time to do your field work, analyze your data, and write your Ph.D. dissertation. Your field work starts in the closest emerged land to the Chicxulub impact site. In no time at all you begin discovering new species of dinosaurs that are unknown from the fossil record, and you diligently test dozens of hypotheses about the behavior and physiology of these Mesozoic giants.
For three years you have that chance to explore a completely different world to the one where you grew up. Australia is still connected to a temperate Antarctica and India is on its way to cross the equatorial line. Continental seas cover extensive regions of North America, Europe, Asia and in South America, east of the rising Andes.
During your last year of field work, a series of small meteorites begin to impact the Earth. These events become more and more frequent and some of them have local effects similar to the volcanic explosion of the island of Krakatau in 1883. Your advisor and dissertation committee recommend that you come back, but you refuse to do so. You still want to do field work for your last chapter concerning the ecology of Titanosaurus in South America. It is literally the last chance to study these sauropods before they become extinct. However, communications with your family and friends make you change your mind. After carefully packing up all your samples, including Ornithuromorpha feathers, Nymphaeaceae flowers and pollinator insects, you come back to the present. The Cretaceous world is not a safe place anymore ….
Our reality today is in some ways not too far from this fictional story. Based in Laupāhoehoe on the Big Island of Hawai’i this past January, I took part in field work on the slopes of Mauna Kea and witnessed how the environment is changing in a precipitous way. I had the chance to do an altitudinal transect with climate change researchers from the University of Hawai’i, Mānoa. Starting at 1,116 meters we were surrounded by an amazingly beautiful native forest. Huge o’hia and koa trees dominated the canopy, while the understory was full of a variety of endemic plants, including the hapu’u fern, ‘ōlapa tree, ‘ōhelo berries and more than 15 other endemic species. Flying and singing amongst the vegetation, different species of native birds, (i’iwi, apapane, ‘oma’o, ‘amakihi) accompanied us. The bark and leaves of the trees hosted an abundant community of terrestrial invertebrates. Dozens of species of Drosophila, giant Leptogryllus crickets, colorful Tetragnatha spiders and, of course, the curious Hawaiian happy face spider, were part of this unique world.
However, as we descended, the increase of invasive species, like strawberry guava, clidemia and Kāhili ginger, became obvious. At 934 meters, most of the strawberry guavas were juvenile — they were the advancing front of an invasion. By 800 meters, the strawberry guava trees were older and the diversity of endemic plants had declined dramatically. Toward the end of the transect, we were in a pure strawberry guava forest. Most of the native plants were gone and many of the animals appeared to be absent as well. It became obvious to me that I was witnessing the potential future for the higher elevation areas.
Today, the disappearance of “critically endangered,” “endangered” and “vulnerable” species could lead us further down a path toward what might be the planet’s sixth mass extinction. Indeed, it is likely that many more organisms will go extinct in our lifetime. The clock is ticking for many species worldwide and we have a limited time to discover and document our existing biological diversity. Unlike the K/T extinction, we can use our knowledge of contemporary species distribution and abundance to prevent these extinctions. However, for this to occur, human society must undergo fundamental yet attainable changes. If we fail to learn the lessons from the past, there might not be a future from which to escape once the Earth ceases to be a safe place ….
Acknowledgement: I want to thank Scott Laursen for suggestions for the text and for letting me join the research team to visit Laupāhoehoe.