Dirk StevensonViews:
In December, I had the opportunity to attend and present at the International Conference for Conservation Biology (ICCB) in Auckland, New Zealand. This was my first visit to New Zealand and I was excited both for the conference, but also the chance to see some unique animals that occur in New Zealand as well as some of the landscapes I had seen in the Lord of the Rings movies. I was invited to attend the ICCB meeting as part of a symposium on the science behind landscape connectivity initiatives. Specifically, I was asked to talk about my work developing resistance surfaces. Resistance surfaces are an important tool for predicting landscape connectivity and are simply a layer that has a cost for movement on each spot on the map that corresponds to landscape features that either help or constrain movement. We can use the resistance surfaces to identify the best areas for wildlife movement through a landscape, and therefore identify the best places to manage or protect habitat. I am currently applying these techniques to help model connectivity of Northern Pacific Rattlesnakes (Crotalus oreganus oreganus) as part of the Washington Wildlife Habitat Connectivity Working Group, and am interested in modeling connectivity for Orianne Society projects as well. Therefore, it was great to be able to not only present my work at the symposium, but also learn about the methods being used by other colleagues that were in the same symposium.
The ICCB meeting was very large (1,300 participants) and there were a lot of other interesting talks that were relevant to my work with The Orianne Society. I attended talks on such topics as reintroduction biology, new advances in genetic techniques, climate change, and even a talk on amphibians that demonstrated that the spectral signature of frog skin could be used to determine species, sex, and disease status! I also learned a lot about the conservation actions taking place in New Zealand. New Zealand does not have any native mammals except for bats, and so the endemic bird, reptile, and insect species are not adapted to mammalian predators. However, the initial Maori settlement and subsequent European colonists brought many mammals including rats, pigs, dogs, cats, weasels, and possum that have decimated many native populations. The Department of Conservation in New Zealand has taken this threat seriously and has taken action to eradicate invasive mammals where possible. This has led to several successful conservation projects on offshore islands and mainland areas with predator-proof fences that have saved several species from extinction, including the tuatara, a “living fossil” reptile that was common during the time of the dinosaurs.
The day after the conference ended, I visited one of these conservation islands near Auckland, Tiritiri Matangi Island. Tiritiri Matangi was formerly an agricultural island with many sheep grazing, but in 1971 was converted to a recreational reserve. Volunteers carried out an extensive revegetation project, and today the island is largely covered in native plants. Invasive mammals were eradicated and native wildlife reintroduced, including the tuatara, kiwi, saddleback bird, and the takahe (a flightless bird thought extinct until rediscovered in 1948). Visiting the island was an amazing experience and I felt like I was entering Jurassic Park – if you exchanged birds for dinosaurs! I was surrounded by birdsong and birds moving through the forest all around me. I also was hoping to see a tuatara while I was on the island. Unfortunately, tuataras are largely nocturnal and overnight accommodations on the island were already booked up. I did keep an eye out for the occasional daytime basker, but was not successful. However, my guide on the island did show me a burrow that tuatara often used, so I was probably only a few feet from this iconic reptile! (And yes, I wished I had one of the cameras that Orianne Society researchers use to see Indigo Snakes, Gopher Tortoises and Eastern Diamondback Rattlesnakes in burrows). I did have some good fortune on this visit. The day I visited was a public release of the wetapunga, otherwise known as the giant weta. The weta is a type of insect found in New Zealand that looks like a giant cricket and eats vegetation in trees. There are several weta species, but the wetapunga is the most endangered and the entire wild population is confined to one island. I hope that its reintroduction on Tiritiri Matangi is successful, and it was a highlight to be able to see this insect up close.
I next visited Great Barrier Island for a few days. Great Barrier Island is a 5-hour boat ride from Auckland and is the second largest offshore island in New Zealand. It does have some of the invasive mammals (rats, cats, pigs) but is missing some of the other predators that have wreaked havoc across New Zealand. As a result, Great Barrier Island has one of the best native species assemblages remaining and many species that are rare elsewhere are common here. This includes the greatest number of reptile and amphibian species found in any one location in New Zealand. In fact, my motivation for the visiting “The Barrier” was to see the native geckos, skinks and frog found there. I was especially interested in the frog, Leiopelma hochstetteri, as it is another living fossil and the close living relative to the tailed frogs in North America, and the chevron skink, Oligosoma homalonatum, which is restricted to Great Barrier and a neighboring island. Unfortunately, a tropical depression stalled over New Zealand during my visit and it rained almost the entire time I was on the island. Despite looking up and down countless trees, no geckos were to be found in the open, and I found only 3 skinks that disappeared into the thick leaf litter before I could photograph them. (I read in the guidebooks that New Zealand lizards were “secretive” and “cryptic”, but I didn’t appreciate the truth of this until my visit). I did conduct some more intensive searches for the Leiopelma frog and the chevron skink based on some areas where these rare species had been found. I was unsuccessful in finding any, but learned a lesson in how mammals alter the critical habitat for these species. At a location that I am pretty sure was a known chevron skink site, I was surprised by the amount of ground disturbance along the stream area, precisely the areas where chevron skinks require undisturbed surface cover. My answer came quickly, as I spooked two large wild pigs that crashed through the understory away from me. The wild pigs had almost completely destroyed the lizard habitat (and probably eaten some lizards as well). This discovery showed me that while New Zealand has made excellent progress in species conservation, its rare species are still threatened in many places.
Although I understood the weather conditions weren’t ideal for herping while I was there, I was still disappointed in the lack of herpetofauna I encountered. In an effort to see at least one gecko in the country, I visited the Auckland Museum right before I left. In addition to preserved specimens, the museum had a collection of live Auckland green geckos (Naultinus elegans) that were even more amazing looking than I had expected. Even in the captive environment, I appreciated the chance to see this endemic gecko and resolved to come back to New Zealand sometime in the future to try again to see some of these unique species in their native habitats.
