Risk of transporting non-native species into Antarctica 南極における外来種持ち込みの危険性
Risk of transporting non-native species into Antarctica
Antarctic terrestrial ecosystems are not immune to the threat of biological invasions, and the urgent need for implementation of effective mitigation measures to minimize the risk of these occurring has been highlighted. Although many of the national operators and independent tour operators that transport personnel and/or cargo into Antarctica have implemented various bio-security procedures in recent years in order to reduce the risk of non-native species introductions, to date no specific bio-security policy or measure has been considered or adopted in the Japanese Antarctic Research Expedition (JARE) operation. In this study, risk of transporting non-native species into Antarctica was identified from the various perspectives associated with the activities of the JARE operations. First, a non-native flowering plant found near Syowa Station was examined in order to identify the species as well as to specify the source of introduction. The species of the grass which was once assigned as Poa cf. trivialis L. was determined based upon the morphological characteristics with the additional examination of the molecular systematics. The results of the study indicated the grass found growing near Syowa Station in Antarctica in 1995 to be included in the Svalbard salt marsh grass, Puccinellia svalbardensis Rønning, endemic to Spitzbergen, Svalbard in Arctic. Whereas a particular dispersal pathway of introducing the Arctic plant into Antarctica was not specified, a possibility of introduction of this species in association with the human activities was considered. The limited development of reproductive organs observed in the grass suggested a possibility of the environmental conditions in the continental Antarctica having prohibited the grass from the successful establishment in the region. However, the successful introduction of an endemic Arctic species in the continental Antarctic region, where no higher plants had previously been reported, demonstrated the considerable risk of introducing non-native species from Arctic into Antarctic. Second, the potential risk of non-native species introduction into Antarctica associated with the current JARE transportation operations was determined. The first part of this study was conducted on the clothing and equipment of the JARE expeditioners on board Shirase under the JARE 49 operation, southbound to Antarctica in the 2007/08 austral summer. The study focused on quantifying propagule attachment and carriage on the various types of clothing and equipment item. The data obtained were combined with characteristics of those items in order to identify those elements posing the significant risk of non-native species transport and introduction in association with the JARE expeditionrs transfer. Number of propagules collected from the clothing and gears of JARE expeditioners examined in this study was found less severe as compared with those results in the similar studies carried out by the other national Antarctic operations. The particular system of JARE operations, under which expeditioners are mostly issued new items, appears to have resulted in the very limited number of propagules encountered on their items. The risk of transporting propagules found in this study was associated with items which had previously been used. The latter part of this study was conducted on the transportation operations to Antarctica under both the old (JARE 49, southbound to Antarctica in the 2007/08 austral summer) and the new systems (JARE 51, 2009/10) in order to identify any specific risks associated with the current and newly-adopted system relative to its predecessor. The study again focused on quantifying propagule attachment and carriage here on the outer surfaces of various types of cargo item. The data obtained were combined with a compositional survey of cargo according to packing types and storage locations in order to identify those elements posing the most significant risk associated with the JARE cargo transport operations. The propagules found attached on the JARE cargo items including species known to have resistance to the stresses of cold environments indicated the potential pressure and risk of those propagules to the Antarctic ecosystem. The highest risk of carrying propagules was associated with the JARE Steel Containers (JARE SCs) especially the larger 12ft containers stored in the open air. The study also demonstrated the increased use of JARE SCs resulting in an increase in the total exposed cargo surface area in the current operation, which in consequence would significantly elevate the risk of non-native species propagule entrainment and transport in the current JARE logistic operation. While the outer structure of the JARE SCs and the location and the structure of the new storage facilities in Tachikawa-shi were considered potential major factors contributing to the large number of propagules obtained in the current system, the higher level of cargo control possible by National Institute of Polar Research (NIPR) under the current JARE Cargo transportation operation was shown. Third, a systematic survey was conducted among four national Antarctic operators, NIPR, Australian Antarctic Division, British Antarctic Survey, and Korea Polar Research Institute in order to assist with the development of best-practice guidelines of bio-security measures to minimize risk of transporting non-native species into Antarctica for the JARE operation. For those categories already identified as potential vectors of transporting non-native species in the previous studies including fresh food, cargo transportation, clothing and equipment of expeditioners, vehicles and ships, bio-security measure of those four operators were compared. Numbers and contents of bio-security measures developed and implemented varied across the four institutions surveyed, and institutions holding stations of historically or currently impacted by non-native species have developed and implemented various management plan and bio-security measures. Although the current policy on expeditioners at NIPR found to be fairly advanced and ideal to avoid the introduction of non-native species into Antarctica, numbers of policies and measures already adapted by other institutions were recommended to be implemented for the JARE operation on other categories. The study provided the plenty of scope for development and improvement of bio-security policies or measures to minimize risk of transporting non-native species into Antarctica to be adopted for the JARE operations. Consideration as well as the development of bio-security measures for the JARE operations based-upon the data presented was highly recommended. This study is the first to have demonstrated the particular risk of transporting propagules associated with the national operations conducting scientific research in polar regions based upon the actual occurrence of an introduced species in Antarctica. The study also provided an overview of the potential propagule pressures in association with the expeditioners and cargo transportation under the current JARE operation. Furthermore, numbers of appropriate preventative measures were proposed for adoption into the JARE operation based upon the findings in order to minimize the risk of transfer of non-native species into Antarctica through the activities of JARE. This study has established a platform for developing the management framework to prevent the introduction of non-native species into Antarctica for the JARE operation.