{"id":327757,"date":"2020-08-07T06:02:20","date_gmt":"2020-08-06T20:02:20","guid":{"rendered":"https:\/\/www.saipantribune.com\/?p=327757"},"modified":"2020-08-07T06:02:20","modified_gmt":"2020-08-06T20:02:20","slug":"uog-study-cycad-size-and-habitat-contribute-to-plants-survival-when-faced-with-invasive-flora","status":"publish","type":"post","link":"https:\/\/www.saipantribune.com\/index.php\/uog-study-cycad-size-and-habitat-contribute-to-plants-survival-when-faced-with-invasive-flora\/","title":{"rendered":"UOG study: Cycad size and habitat contribute to plant\u2019s survival\u00a0when faced with invasive flora\u00a0"},"content":{"rendered":"
\"\"<\/a>
A\u00a0Cycas micronesica\u00a0tree in Guam, right, shows the extent of damage done by invasive insect herbivores, a\u00a0scale called\u00a0Aulacaspis yasumatsui,\u00a0as compared to a healthy\u00a0Cycas micronesica\u00a0tree, left, found in Yap. In a 15-year study, published in the May 2020 issue of Diversity journal, researchers studied the rate and influences of mortality in Guam cycads affected by invasive species.\u00a0(UNIVERSITY OF GUAM)<\/figcaption><\/figure>\n

A long-term study in Guam and Micronesia\u2019s native and threatened species of cycad plant has revealed\u00a0factors that contribute to the plant\u2019s ability to survive in the face of invasive species.<\/p>\n

Research out of the Western Pacific Tropical Research Center at the University of Guam and College of Micronesia-FSM shows that the\u00a0Cycas micronesica\u00a0population in Guam declined to 4% of its population size from 2005 to 2020 following the introduction of the non-native scale insect,\u00a0Aulacaspis yasumatsui, in 2003, and the cycad-eating butterfly,\u00a0Chilades pandava, shortly thereafter. Of the few cycads that survived or survived the longest, plant size and habitat traits were key.<\/p>\n

\u201cGuam\u2019s\u00a0Cycas micronesica\u00a0was the most abundant tree [in] Guam two decades ago, but\u00a0then an onslaught of non-native insect herbivores invaded the island and initiated sweeping mortality,\u201d said Adrian Ares, associate director of the Western Pacific Tropical Research Center.<\/p>\n

The plant variety is also found on the Northern Mariana Island of Rota, the Federated States of Micronesia island of Yap, and Palau, though the two invasive herbivores are not present in Yap or Palau.<\/p>\n

In establishing 120 permanent plots where the plant grows in Guam in 2005 and examining them over 15 years, the researchers found that 100% of seedlings were killed by 2006 and 100% of juvenile plants were killed by 2014.\u00a0The persisting plants were larger individuals that possessed substantial stored resources.<\/p>\n

\u201cThe means by which the invasion of an island by a non-native herbivore can wreak such havoc is actually two-fold,\u201d said Murukesan V. Krishnapillai, a research scientist at the College of Micronesia-FSM and one of the authors of the study. \u201cFirst, the native tree that is attacked by the new pest has spent millennia evolving without a comparable herbivore and, therefore, possesses few defensive strategies. Second, the pest has escaped from its own native habitat, where it co-evolved with natural enemies, and, therefore, the new island environment contains no natural enemies to tamp down the pests\u2019 population growth.\u201d<\/p>\n

The study also illuminated two other spatial factors that have influenced the plant population\u2019s response to the non-native insect herbivore threats. First, the populations in Western localities have exhibited much higher mortality than the populations in Eastern localities. Second, the plants within large contiguous forests have exhibited less damage than plants within forest fragments.<\/p>\n

The long-term nature of the study, which Ares said is rare in contemporary academia, and the use of benchmarking starting in 2005 were crucial in understanding how rapidly threats can devastate island tree populations.<\/p>\n

Knowing that plant size and habitat traits influence cycad susceptibility to non-native threats can now inform conservation management decisions.<\/p>\n

\u201cConservationists need developing knowledge like this to craft the most appropriate mitigation strategies and identify where available funds should be spent,\u201d Ares said.<\/p>\n

The study concluded that the only high priority activity to conserve the\u00a0Cycas micronesicaspecies where the scale and butterfly are present is to establish a complex integrated biological control program under the direction of scientists with international expertise.<\/p>\n

The study is published in the May 2020 issue of Diversity, a peer-reviewed journal published by MDPI.\u00a0(UOG)<\/p>\n","protected":false},"excerpt":{"rendered":"

A long-term study in Guam and Micronesia\u2019s native and threatened species of cycad plant has…<\/p>\n","protected":false},"author":28,"featured_media":327760,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4],"tags":[445],"class_list":["post-327757","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-local-news","tag-uog"],"_links":{"self":[{"href":"https:\/\/www.saipantribune.com\/index.php\/wp-json\/wp\/v2\/posts\/327757","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.saipantribune.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.saipantribune.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.saipantribune.com\/index.php\/wp-json\/wp\/v2\/users\/28"}],"replies":[{"embeddable":true,"href":"https:\/\/www.saipantribune.com\/index.php\/wp-json\/wp\/v2\/comments?post=327757"}],"version-history":[{"count":0,"href":"https:\/\/www.saipantribune.com\/index.php\/wp-json\/wp\/v2\/posts\/327757\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.saipantribune.com\/index.php\/wp-json\/wp\/v2\/media\/327760"}],"wp:attachment":[{"href":"https:\/\/www.saipantribune.com\/index.php\/wp-json\/wp\/v2\/media?parent=327757"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.saipantribune.com\/index.php\/wp-json\/wp\/v2\/categories?post=327757"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.saipantribune.com\/index.php\/wp-json\/wp\/v2\/tags?post=327757"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}