Gilianne D. Brodie

Histological investigations on Dendrodoris nigra (Stimpson, 1855) (Gastropoda, Nudibranchia, Dendrodorididae)

Abstract The histology of the major organ systems (digestive, reproductive, nervous, circulatory, excretory and respiratory, as wdl as epidermis) of the nudibranch Dendrodoris nigra (Stimpson, 1855) arc described for the first time and the results are compared with those derived from other members of the Doridoidea. It is shown that some characters which have been used to differentiate the genus Dendrodoris Ehrenberg, 1831 from other doridoideans (i.e., retractability of gills, lack of hard structures in the anterior digestive system, presence of pericardial glands) are problematic when used for phylogenetic ,analysis. This is especially true when taking into consideration that little is known about details of these structures in the Doridoide, as a whole.

Increases in crop pests caused by Wasmannia auropunctata in Solomon Islands subsistence gardens

The impacts of Wasmannia auropunctata (the little fire ant) on the native biota and subsistence agriculture in the Solomon Islands are poorly understood. This species was originally introduced as a biological control against nut‐fall bugs (Amblypelta sp.) around 30 years ago and in the intervening time has spread throughout the Solomon Islands, aided movement of produce and planting material. It is now itself a major pest of coconut, cocoa and subsistence agriculture. In this study, we show the negative effects of this invasive ant on subsistence agriculture in the Solomon Islands. We do this by (i) assessing the presence of insect pests that develop a mutual relationship with W. auropunctata on four common subsistence crops; and (ii) measuring the impact of a significant pest (Tarophagus sp.) and its natural predator the bug Cyrtohinus fulvus, in the presence and absence of W. auropunctata on taro crops. The existence of insect pests that form a mutual relationship with W. auropunctata was measured in a total of 36 gardens of the four subsistence crops. This was conducted through standardized visual searches, plus identification and collecting from randomly selected plants within the gardens. A number of additional insect pests causing major problems to subsistence crops have also developed mutual relationships with W. auropunctata. Infested taro gardens have more Tarophagus sp. compared with taro plants that are free of the little fire ant. The presence and abundance of Wasmannia therefore has the potential to inflict considerable crop loss in rural subsistence gardens in the Solomon Islands.

An appraisal of sampling methods and effort for investigating moth assemblages in a Fijian forest

The moth assemblages in forest ecosystems are often used as indicators of forest quality and to monitor the effects of habitat degradation or ecological restoration and management. However, to provide meaningful data on nocturnal moth faunas, it is important to evaluate the efficacy of available sampling methods and identify the minimum number of samples needed to obtain a reliable estimate of moth diversity. This study compared three light‐based collecting methods to sample nocturnal moths in Colo‐i‐Suva Forest Reserve, a lowland mixed forest 8 km north of Suva, Fiji Islands. On average, over eight nights collecting, a mercury vapour light (MV) with manual capture obtained approximately 14 times more individuals and five times more species than a white fluorescent light with automatic capture and ultraviolet light with automatic capture. Of the 84 moth taxa recorded in total, only two were not obtained by the MV trap, suggesting the moth assemblages obtained by the fluorescent light and ultraviolet light methods were subsets of the larger MV collection. Using a bootstrap method to estimate the total species collected after successive nights sampling, we found that after four nights almost 90% of the predicted total moth species would be obtained by the MV method. These results identify the MV method as a high‐performing technique to investigate nocturnal moth diversity in Fijian forests, and that a minimum of four nights sampling with this protocol would produce reliable data for use in habitat evaluation.

The use of herpetofauna and cultural values to identify priority conservation forests on Malaita, Solomon Islands

Due to limited financial and technical resources, there is a pressing need to identify priority areas and strategies for conservation globally. This study aims to prioritize important forest areas for conservation on the island of Malaita, Solomon Islands. Five different forest types were sampled to quantify biodiversity using the species richness of frogs and lizards (herpetofauna) as a biological indicator of conservation status. Unlogged coastal, unlogged lowland and unlogged upland forests have minimal disturbance whereas logged lowland forests and plantation teak forests are heavily disturbed. Subsequently, the effects of human modification on forest systems are also quantified based on anthropogenic disturbance. Interviews with local community members were conducted to gather associated local traditional knowledge on the cultural importance of frogs, lizards and forest habitats. Prioritization methods based on species richness, species uniqueness, cultural importance and threatened status are used to identify key forest areas. The four main results found are: 1) unlogged lowland forests have the greatest biodiversity value, 2) unlogged lowland forests also have the highest cultural value based on local uses, 3) logged lowland forests are biologically important, and 4) unlogged coastal forests and unlogged lowland forests are under the greatest threat from anthropogenic activities. Based on these results, the conservation of unlogged lowland forests on Malaita should be prioritized. These results also highlight the importance of combining biological sampling with cultural information to improve the efficiency and long-term success of conservation actions.

A preliminary study into the potential of mayflies (Ephemeroptera: Baetidae and Caenidae) as bio-indicators of stream health in Fiji

flowing through an area of tropical lowland rainfor est and urban streams running through residential and indus trial areas. The two rural streams were Waisila Stream l ocated within the Colo-I-Suva Forest Reserve approximately 6 km from Suva and the Savura water catchment within the forested area of the upper Wailoku River. The two urban streams were the Nabua stream where it runs through an army barracks and the Nabukalou creek running directly through Suva city centre. Mayfly nymphs were sampled from riffles in each stream by lifting ten rocks and vigorously brushing the surface of each with a soft brush while a fine-mesh net was held down stream. All mayfly nymph specimens were preserved in 80% ethanol until being examined under a dissecting microscope and identified to family leve l according to Dean and Suter (1996). Five samples of nymphs were collected from five replicate sites in each stream (approximately 10m of stream length) on each stream. The samples collected within each site wer e then pooled.

Disappearing jewels: An urgent need for conservation of Fiji's partulid tree snail fauna

Where conservation status of island non-marine molluscs is known, snails tend to be one of the most threatened faunal groups. However, published information regarding island gastropod conservation status, diversity and endemism is frequently unavailable despite the importance of this information for the formulation of biodiversity action plans and conservation strategy. Fiji, for example, has a diverse native land snail fauna (>240 species) with an endemism level of ~80%, but only within the last few years has any information about any of these species been available to the national biodiversity reporting repository. For one lineage in particular, members of the tree snail family Partulidae, with four endemic Fiji Island species, the conservation status of the group has never been assessed. However, based on the alarming extinction rates documented in partulid snail species on other Pacific Islands, information about the occurrence and status of these taxa is urgently needed for Fiji’s biodiversity action plan. To redress this information void, we formulated the Fijian Partulid Tree Snail Project, consisting of five components: (1) raising awareness; (2) locating populations and monitoring population trends; (3) elucidating patterns of genetic diversity; (4) creating action partnerships; and (5) conducting disturbance gradient analyses. The overall goal was to characterise mechanisms leading to persistence of partulids in the face of increasing anthropogenic disturbance. In the initial stages of this project, existing information on Fiji’s partulids was collated and two small, remote islands in the Fiji archipelago were surveyed to investigate whether tree snails persisted there. Living populations of Partula lanceolata and empty shells of Partula leefei were found on Cicia Island in Lau, and on Rotuma Island in the Rotuma Group, respectively. DNA analyses confirm a sister relationship between the two Partula species in north-eastern Lau, P. lirata and P. lanceolata, with both sharing a sister relationship with a member of the same genus in Vanuatu – P. auraniana Hartman, 1888. Prioritisation and further sampling of additional islands, and residual native habitat on less accessible islands and islets, is needed to fully assess the conservation status of all four Fijian species via the IUCN Red List process. Moreover, the basic descriptive information and associated studies reported here will serve to raise awareness of Fiji’s endemic tree snails particularly in communities that had no prior knowledge of their special conservation status; and also at a wider national, regional and global level. Community awareness is particularly vital as the willing support of land owners in the relevant small island communities is critical to implementing any future conservation action plans.

Temporal Variation in Macro-Moth Abundance and Species Richness in a Lowland Fijian Forest

Abstract: In this study we investigated temporal patterns in activity of adult macro-moths in Colo-i-Suva mixed lowland tropical forest on Fijis largest island, Viti Levu. Moths were collected for 2 or 3 nights per month over a 12-month period using a mercury-vapor light as an attractant and collecting moths that had settled onto a white sheet for 4 hr after dusk. In total 1,397 specimens were captured, belonging to 116 species in 10 families. There were no significant relationships between total abundance and species richness with any of the climatic factors measured: average minimum and maximum daily temperature, average daily rainfall, and relative humidity. There were no obvious trends in total abundance and species richness over the 12-month monitoring period, although multivariate analysis suggested that moth assemblages in the wet and dry seasons were distinct in terms of their composition. These differences appear to be caused by some of the more-common species exhibiting clear peaks in abundance at certain times of the year, whereas other less-common species were restricted to only dry-season or only wet-season samples. We believe that this study is the first to obtain detailed information on flight periods of adult macro-moths in Fiji. Further research is required to ascertain whether patterns we have observed at this location repeat themselves in subsequent years, and to compare seasonal patterns of moths in other forests, other habitats, and other Fijian islands.

Diversity and current conservation status of Melanesian- New Zealand placostyline land snails (Gastropoda: Bothriembryontidae), with discussion of conservation imperatives, priorities and methodology issues

We review the diversity and conservation status of Placostylinae, land snails endemic to the western Pacific. Their narrow-range endemism, large size and associated vulnerability, consumptive exploitation by people, and habitat loss and degradation (inclusive of invasive predators) threaten their survival. There has been considerable attention from conservation biologists in New Caledonia, Lord Howe Island and New Zealand aimed at species recovery. Nonetheless, only on uninhabited, pest-free islands do these native snails persist in high numbers, and these remaining ‘sanctuaries’ are dependent on biosecurity vigilance. For other populations in New Caledonia, Lord Howe Island and New Zealand, the benefits of control of invasive mesopredators have been demonstrated, but it remains unclear if long-term persistence of Placostylinae can be achieved in degraded landscapes that continue to be subject to anthropogenic pressures. For species in Fiji, Vanuatu, and the Solomon Islands – the centre of Placostylinae diversity – their conservation status is not known with any certainty due to lack of basic data on range and population trends. Recent IUCN Red List assessments indicate a high level of extinction risk among Fijian species due to narrow geographic range coupled with decline in habitat extent and quality. Further inventory and ecological work is urgently needed in the Solomon Islands and Vanuatu to enable assessment of extinction risk and identify threatening processes. We identify four priority areas for advancing the conservation of Placostylinae, especially in Melanesia, and discuss the most pressing methodological issues. Molecular phylogenetic analyses are needed to provide an evolutionary framework for taxonomic revision and to underpin development of both conservation policy and species recovery plans.