Using Historical Data to Track Long Term Climate Impacted Trends and Resilience in Atoll Landscapes and Biodiversity

The tropical Pacific and Indian Oceans have been undergoing terrestrial community collapse from climate change induced sea-level rise and storm surges, with many ecosystems, such as atolls, at significantly higher risk. Within the tropical Pacific, very few atolls have a suitable or adequate baseline of fauna data to evaluate climate driven shifts in distribution and persistence, compared to other drivers such as invasive species.

From the 1950s to the 1960s, the Pacific Science Board of the National Research Council and Department of Navy instituted various baseline surveys across the Pacific, in some cases repeating the earlier American Museum of Natural History Whitney Expedition Surveys of the 1920’s. One place that became a focus, however, was Arno Atoll in the Marshall Islands. Researchers discovered a unique and interesting pattern of the distribution of lizards of the genus Emoia across the islets. This pattern was further evaluated in 1968 resulting in a paper that offered hypotheses about the correlation between atoll islet size and patterns of lizard occurrence. More recently, in the 1990s, it was discovered that both the maternal and paternal ancestor of the parthenogenetic mourning gecko (Lepidodactylus lugubris) also occur on Arno Atoll. It was hypothesized that their co-occurrence on small islets allowed for the hybridization which led to its origin, and its eventual spread to become one of the most globally occurring gecko species.

Because this historical data is at such a fine scale of spatial accuracy, we can utilize it to study a 50+ year window of change in both islet size and lizard community structure. This project will evaluate if there are any range reductions or shifts to better determine the distribution of the geckos through the lens of potential storm surges, atoll size reductions, and increased cyclones on the decadal scale.