Skip to main content

Search the SPREP Catalogue

Refine Search Results

Related Countries

Language

Available Online

Related Countries

Available Online

77 result(s) found.

Sort by

You searched for

Seasonal patterns in ichthyofaunal communities of fresh and estuarine wetlands in Vanua Levu, Fiji : a technical report for the Fiji Ecosystem based management project
Biodiversity Conservation
Available Online

Jenkins, Aaron P.

,

Mailautoka, Kinikoto

2009
As a component of the Fiji Ecosystem Based management project, this study examined seasonal patterns of variation in the ichthyofaunal communities in seven river systems in Macuata and Kubulau districts, Vanua Levu, Fiji. The study was designed to determine the abundance, diversity and biomass of fishes within different reaches of the systems during the wet and dry seasons. Catchment characteristics clearly distinguish the districts in terms of potential impacts on ecological integrity. Macuata catchments, on average, are much larger (25789 vs 3306 ha), possess much less natural forest cover (49.6 vs 76 %), have greater density of roads (1.7 vs 0.51/km2 ) and river crossings (1.4 vs 0/km2 ), and are heavily invaded by exotic species Oreochromis spp and Gambusia affinis. Rainfall patterns are similar during the wet season for the districts but Kubulau has on average twice the rainfall during the dry season. 1616 individual fishes were collected or observed from 32 families, 19 genera and 87 species both seasons. 12% more species were seen during the wet season (68 vs 58), however the two districts show conflicting patterns with higher numbers of species in the wet in Kubulau District and higher numbers of species in the dry in Macuata District. Over half of species were observed in only one season (55%), 19 (21%) species only in the dry, 29 (33%) only in the wet. Proportions of life history patterns remain relatively consistent across both seasons although there are 6 % more estuarine migrant species (particularly mud dwelling species) and 1 % more amphidromous species in the wet while there is a 4% increase in freshwater straggler species in the dry mainly driven by additional pipefish species. It is clear that Kubulau, despite its smaller average catchment sizes is significantly (p = 0.035) more diverse than Macuata. Examination of community structure across reach and season suggest that position in river reach is a greater determinant of what species are in a community than season. A conflicting pattern between the districts with regard to seasonal influence on species richness, diversity, abundance and biomass of fishes if taken in conjunction with the water quality information, suggests the wet season is having a net positive effect on habitable space for fishes in Kubulau District and having a net negative effect in Macuata District. This result suggests degraded catchments are losing ecological resilience and natural responses to cycles of seasonal change. Comparison of mean abundance and biomass in Vanua Levu to the pristine rivers of Tetepare Island, Solomon Islands suggest that the rivers of Vanua Levu are already severely ecologically compromised and in most cases adequate biomass for food utilization is only energetically worthwhile in lower reaches.
Integrated assessment of wetland services and values as a tool to anlayse policy trade-offs and management options: A case study in the Daly and Mary River catchments, northern Australia : final report
Biodiversity Conservation
Available Online

de Groot Rudolf ... [et al.].

2008
In this report we present the results of a study carried out between May 2004 and May 2005 as a contribution to the Tropical Rivers Inventory and Assessment Project (TRIAP) of Australia's Tropical Rivers Program. The aim was to provide a framework for the analysis of the ecosystem services provided by the wetland and riverine ecosystems of northern Australia. The analyses drew heavily on the conceptual framework provided by the Millennium Ecosystem Assessment (MA) where ecosystem services were defined as 'the benefits people obtain from ecosystems'. These benefits include: provisioning services such as food and water; regulating services such as flood and disease control; cultural services such as spiritual, recreational, and cultural benefits; and supporting services such as nutrient cycling that maintain the conditions for life on earth. The term 'ecosystem services' is now broadly used to encompass what can also be referred to as ecosystem goods and services and/or ecosystem functions and, at times, also environmental services. For the purposes of this report - given that the study was undertaken using the recognised 'function analysis framework' - the terms ecosystem services and functions are considered to be interchangeable unless a distinction is made otherwise.
Threats to mangroves from climate change and adaptation options
Climate Change Resilience, Biodiversity Conservation
Available Online

Duke Norman C

,

Ellison Joanna

,

Field Colin

,

Gilman, Eric L

2008
Mangrove ecosystems are threatened by climate change. We review the state of knowledge of mangrove vulnerability and responses to predicted climate change and consider adaptation options. Based on available evidence, of all the climate change outcomes, relative sea-level rise may be the greatest threat to mangroves. Most mangrove sediment surface elevations are not keeping pace with sea-level rise, although longer term studies from a larger number of regions are needed. Rising sea-level will have the greatest impact on mangroves experiencing net lowering in sediment elevation, where there is limited area for landward migration. The Pacific Islands mangroves have been demonstrated to be at high risk of substantial reductions. There is less certainty over other climate change outcomes and mangrove responses. More research is needed on assessment methods and standard indicators of change in response to effects from climate change, while regional monitoring networks are needed to observe these responses to enable educated adaptation. Adaptation measures can offset anticipated mangrove losses and improve resistance and resilience to climate change. Coastal planning can adapt to facilitate mangrove migration with sea-level rise. Management of activities within the catchment that affect long-term trends in the mangrove sediment elevation, better management of other stressors on mangroves, rehabilitation of degraded mangrove areas, and increases in systems of strategically designed protected area networks that include mangroves and functionally linked ecosystems through representation, replication and refugia, are additional adaptation options.