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View the PDF document An assessment of the impacts of climate change on cultivated pulaka (cyrtosperma chamissonis) in Tuvalu
Author:Tekinene, Mataio
Institution: University of the South Pacific.
Award: M.Sc.
Subject: Taro -- Climatic factors -- Tuvalu, Taro -- Effect of global warming on -- Tuvalu
Date: 2014
Call No.: pac SB 211 .T2 T452 2013
BRN: 1194639
Copyright:Over 80% of this thesis may be copied without the authors written permission

Abstract: The purpose of this research is to determine the factors that influence the concentrations of groundwater salinity and soil cations; and to examine their impacts on pulaka cultivation in Tuvalu. To meet these objectives, the research therefore aims to: (i) investigate the local community’s perception of vulnerability impact and adaptation/coping mechanisms of food crops to climate change and extreme events; (ii) assess the factors affecting salinity of water and soil cations in Pulaka pits; (iii) identify potential adaptation options and coping mechanisms for community adoption to sustain and improve Pulaka production; and (iv) undertake follow up salinity monitoring in the Pulaka pits previously sampled by Webb 2007 and Rao 2010 and compare their findings with this study. The methodology used in this study comprise of: (i) a literature review; (ii) a survey using a questionnaire to interview farmers and community members from the 3 study sites; (iii) informal discussion with youths and Form 2 students; (iv) physical assessment of pulaka pits; (v) groundwater testings for salinity, EC and TDS; and (vi) soil sampling to analyse available nutrients. A wide range of perceptions were obtained from community members pertaining to the socioeconomic and cultural importance of pulaka. Traditional knowledge on planting, conservation, common use and other traditional related opinions on pulaka were recorded and discussed to facilitate future decisions for coping mechanisms. Strategic adaptation options and community recommendations are amongst the coping mechanisms discussed herein. The overall groundwater salinity values in pulaka pits were found to differ from pit to pit and even within pits. Additionally, there were areas of very high salinity values such as Nukulaelae’s Motutala Pit and Funafuti’s Central Pit. Nukulaelae had the highest groundwater salinity values at 7.0 ppt, followed by Funafuti at 3.72 ppt and Niutao scored the least at 0.66 ppt. vii Overall correlation analysis between the tested parameters TDS, EC and Salt, the results shows high correlation in Funafuti and Nukulaelae with R2 values above 0.9 while Niutao had much low correlation with values ranging from 0.4 - 0.6. On the other hand, their correlation analysis with environmental parameters (tide, rainfall and maximum temperature) reveals that; for Niutao apart from pH tide difference with R2 value of 0.1353 all other parameters have R2 values less than 0.01; Funafuti have R2 values ranging from 0.0002 - 0.03 and Nukulaelae with values ranging from 0.0002 - 0.004. The 2-Way ANOVA analysis reveals that there is significance difference in pH and Salt with p-values of 0.0325 and 0.00331 while EC, Temperature and TDS have no significant differences at p-values at 0.0596, 0.200 and 0.0838. Tuvalu soil is of calcareous formation that requires tremendous effort to modify and enrich for pulaka growth and that of other traditional food crops. Soil analysis reveals that the exchangeable cations (Ca, Na, Mg ) are all very high and at toxic levels for crop growth in both the affected and unaffected pits. In conclusion, it would appear that the issues surrounding pulaka cultivation in Tuvalu are more complex than the analysis of factors such as tide movement, rainfall, sunshine and maximum temperature reviled. The likelihood that affected pits had anaerobic soil as a result of water-logging, the abandonment of pits by owners as a result of giving up due to salt intrusion, shift in diet to imported foodstuffs and the lack of interest nowadays to cultivate pulaka, are some important finding from this study that will require future investigation.
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