Plants and animals that can claim nativity on one of the many islands in the western Pacific Ocean usually enjoy a tranquil utopia as the lazy days come and go. The views are stunning, the hardships are scarce, and the weather is benevolent. Erratum: the weather is almost always benevolent.
Calling this part of the world your utopian home comes with an annotation. The western Pacific Ocean has the distinction of being the most active tropical cyclone region globally. These violent storms can defoliate and maim, leaving destruction in the aftermath.
Animals can run and hide during these ephemeral events. But native plants are immobile, and therefore have evolved a remarkable ability to withstand the violence. That is, unless the myriad ways that humans destroy nature gets factored in. A recent article from the island of Guam illuminated how non-native insect species inadvertently introduced to Guam by human activity altered a native tree’s natural resistance to tropical cyclone damage.
The event that enabled the research occurred on 15 May 2015 when Typhoon Dolphin visited Guam. “This typhoon was the first to bring tropical cyclone winds to Guam’s forests subsequent to the invasions of several specialist insects that damaged the island’s native cycad species Cycas micronesica,” said Thomas Marler. “We were afforded an opportunity to observe typhoon damage to the cycad population for the first time since health of the plants had been compromised by the alien insects.” Marler teamed up with coauthors John Lawrence and Gil Cruz to publish the results in the September 2016 issue of the Journal of Geography & Natural Disasters.
The native tree species was listed as endangered shortly after the insect herbivore invasions. Thereafter, several conservation management plots were established with the goal of saving the cycad trees within the plots. One of the anticipated consequences of chronic insect infestations was a decline in the resistance of this tree’s unique stem design to typhoon damage. Using the knowledge that future typhoons would impact the new management plots, the team used positioning of the plots within varied slope aspects as a means of using Guam’s topographic features to protect some plots regardless of tropical cyclone wind direction. This approach proved valuable during Typhoon Dolphin with stem failure damage varying 19-fold among the sites of the plots. Two years of active management within the conservation plots greatly lessened the stem failure typhoon damage caused by the chronic insect infestations.
The results illuminate an example of the conservation concept called adaptive resource management. This form of management is often required when conservationists are faced with the task of managing a resource when very little is known about what to do. Decisions made under this framework of uncertainty are enacted in a way that verifying the soundness of those naïve decisions can occur over time. The end result of the iterative process is that management decisions can then be improved by learning as you go. The initial prediction by the conservation team formulated without direct evidence guided several early management decisions. The soundness of those decisions was confirmed by the stochastic visit of Typhoon Dolphin.