| || || Lowry, Brenda Jarvis|
| || || Biogeography of invasive woody plants along a tropical urban-rural gradient in the greater Suva area, Fiji|
Author:Lowry, Brenda Jarvis
Institution: University of the South Pacific.
Subject: Invasive plants -- Fiji -- Suva -- Geographical distribution, Biogeography -- Fiji -- Suva
Call No.: pac SB 613 .F5 L69 2016
Copyright:Under 10% of this thesis may be copied without the authors written permission
Abstract: Like many developing countries, Fiji is experiencing rapid urbanization, and as an island nation is particularly vulnerable to the effects of invasive species. This study examines the relationship between urbanization and the presence and abundance of dominant invasive woody plants (IWP) along an urban-rural gradient in the Greater Suva Urban Area (GSUA), Fiji. Previous research suggests that plant presence in urban settings is driven by human preferences and resources (e.g. favored domesticated plants and resources to control unwanted plants), and that plants appear to follow the intermediate disturbance hypothesis (i.e. greater richness in areas of moderate urbanization). Most studies have been carried out in temperate, developed mainland countries. This research tested whether similar findings apply in a less developed, tropical island country. This study hypothesized that: 1) IWP presence and abundance in the GSUA would vary along the urban-rural gradient due to varying human preferences and resources in relation to each species’ biological characteristics and ecological requirements, and that 2) based on the intermediate disturbance hypothesis, invasive woody plant species richness would increase with distance from the city center but then decrease toward the rural end of the gradient. Within a 29 km long transect from Suva City’s central business district to rural zones beyond Nausori Town, roughly 150 randomly generated sample sites were surveyed for 14 target species. Abundance patterns of the IWP were analyzed using descriptive graphs, GIS mapping, and statistical modeling. Historical, biological and ecological characteristics of each species were also examined as a means of understanding observed spatial patterns along the urban-rural gradient. Findings from this study confirm Hypothesis 1, and partially support Hypothesis 2, and by extension support the applicability of research in temperate, developed mainland countries to tropical, developing countries. A notable difference, however, between developed and developing countries in terms of IWP is the lack of resources to combat the problem in developing countries. It has been established that Pacific islands have more alien species than similarly sized mainland areas. Thus, alien species pose a much larger threat to countries like Fiji than to developed 6 nations, and therefore, prioritization of the most problematic invasive plant species is critical to successful management. Findings from this research help meet this critical need by identifying eight target IWP species which should be prioritized for management in the GSUA: Coccina grandis, Merremia peltata, Mikania micrantha, Piper aduncum, Psidium guajava, Schefflera actinophylla, Solanum torvum, and Spathodea campanulata.