Invasive insects cause staggering impact on a native Guam tree

EurekAlert: The beautiful, endemic and endangered cycad, Cycas micronesica was once a dominant forest tree on the island of Guam, but recent plant mortality predicts extirpation from Guam habitats by 2019. This dire prediction by scientists at the Western Pacific Tropical Research Center (WPTRC), University of Guam is validated by the research of Thomas E. Marler and John H. Lawrence, which has concluded that Cycas micronesica is the only native host for the invasive scale insect Aulacaspis yasumatsui. "The potential cascading ecosystem responses are yet to be completely understood," says WPTRC research scientist Marler.

The armored scale insect A. yasumatsui attacks several cycad genera, but only members of the Cycas genus are killed by the pest. Around twenty years ago the insect was unintentionally introduced to an area in southern Florida known for the production and exportation of Cycas revoluta. The scale was documented in Hawaii in 1998 and in Guam in 2003, and by 2005 it was found in native limestone forest habitat close to the initial outbreak site.

"We looked for native habitats that would be representative of the general cycad populations where we could study population-level response to the devastating scale pest. Our data showed the number of months for juvenile plants to reach 100% mortality was dependent on size and other demographic features," says Marler.

Just like the human body, plants exposed to constant stresses eventually become weakened and unable to withstand additional stresses that by themselves would not be fatal. After the scale invasion, mature C. micronesica trees began to succumb to other pressures. These other factors contributing to the plant mortality include two other invasive insects that enjoy eating cycad salads for dinner: the cycad blue butterfly (Chilades pandava) and a tiny moth (Erechthias sp.).

"During the time frame of our study, cycad scale has been found in Rota in 2007 and in Palau in 2008," says Marler. "The spread of A. yasumatsui in the region underscores the importance of empirical studies to inform conservation efforts on Guam and the rest of Micronesia."

Semicircle of Cycad (Cycadales) leaves looking up trunk. Palm House, Kew Gardens. Shot by Ian Alexander, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license

Will Guam adapt to climate change?

Kim O'Connor in GuamPDM.com: Imagine Gov. Eddie Calvo, Lt. Gov. Ray Tenorio, and our 15 senators suiting up in scuba gear for the next Guam Legislature meeting. A couple years ago, the first underwater cabinet meeting took place in the Maldives, a small island nation in the Indian Ocean. Maldives' President Nasheed and the nation's ministers communicated through hand signals and passing around an agreement while fish and coral surrounded them at 13 feet underwater.

About 80 percent of the Maldives is less than a meter above sea level, and the president wanted to bring awareness to ordinary people around the world by demonstrating the urgent need to address climate change and the rising sea levels, as their islands may become uninhabitable within the century.

Nauru, the world's smallest independent nation, also is seeking global action to address climate change and the correlating rising sea levels. Nauru is located about 34 miles south of the equator. Many islands in our region are vulnerable to natural disasters such as typhoons, tsunamis, flooding and earthquakes, but with only eight square miles, Nauru is experiencing elevated threats. The island's highest elevation is just over 200 feet above sea level, so with rising waters and flooding, the eight square miles can quickly become contaminated or diminished.

...."The stakes are too high to implement these measures only after a disaster is already upon us. Negotiations to reduce emissions should remain the primary forum for reaching an international agreement," The New York Times reported...

Tumon Bay in Guam, public domain photograph by Abasaa 日本語: あばさー

Guam, protecting reefs from the US Navy

Islands Business: Guam Governor Felix P. Camacho summed it up best when he said that the US military buildup “is the largest threat to coral reefs” on his island. Other Micronesian islands echoed his sentiment, which helped set the tone at the 2010 US Coral Reef Taskforce Meeting held on Saipan from September 15 and 16.

The US Coral Reef Taskforce is one of the foremost policy groups guiding national and international coral reef conservation. Among the major projects related to the military buildup in Guam that will impact coral reefs is a deep-draft wharf for transiting aircraft carriers.

The US Navy earlier chose the Polaris Point in Guam’s Apra Harbor as its preferred site for a carrier berth. But the Record of Decision for the Guam and CNMI military buildup’s final environmental impact statement, signed on September 21, noted that the Navy had deferred making a decision on a specific location for a transient CVN berth in Apra Harbor and voluntarily collected additional data on marine resources in the two alternative site locations.

Camacho asked the US Coral Reef Taskforce to help Guam come up with the best possible mitigation strategies for its coral reefs during the military buildup. “The members have the ability to direct resources to this important and urgent task, and techniques and strategies developed for Guahan could have future uses in other locations facing major development as well,” he said.

But Capt. Peter S. Lynch, commanding officer of the US Naval Facilities Engineering Command, said it’s not only the military buildup that’s impacting coral reefs, citing runoff from a construction site or wastewater treatment that’s not properly treated could create algae plumes….