Day M.D.,Economic Development and Innovation |
Kawi A.,National Agriculture Research Institute |
Kurika K.,National Agriculture Research Institute |
Dewhurst C.F.,P Oil Inc. |
And 7 more authors.
Pacific Science | Year: 2012
Mikania micrantha or mile-a-minute is regarded as a major invasive weed in Papua New Guinea (PNG) and is now the target of a biological control program. As part of the program, distribution and physical and socioeconomic impacts of M. micrantha were studied to obtain baseline data and to assist with field release of biological control agents. Through public awareness campaigns and dedicated surveys, M. micrantha has been reported in all 15 lowland provinces. It is particularly widespread in East New Britain, as well as in West New Britain and New Ireland. A CLIMEX model suggests that M. micrantha has the potential to continue to spread throughout all lowland areas in PNG. The weed was found in a wide range of land uses, impacting on plantations and food gardens and smothering papaya, young cocoa, banana, taro, young oil palms, and ornamental plants. In socioeconomic surveys, M. micrantha was found to have severe impacts on crop production and income generated through reduced yields and high weeding costs, particularly in subsistence mixed cropping systems. About 89% of all respondents had M. micrantha on their land, and 71% of respondents had to weed monthly. Approximately 96% of respondents in subsistence mixed cropping systems used only physical means of control compared with 68% of respondents in other farming systems. About 45% of all respondents estimated that M. micrantha causes yield losses in excess of 30%. These studies suggest that there would be substantial benefits to landholders if biological control of M. micrantha were to be successful. © 2012 by University of Hawai'i Press.
Novotny V.,University of South Bohemia |
Miller S.E.,Smithsonian Institution |
Baje L.,University of Papua New Guinea |
Balagawi S.,National Agriculture Research Institute |
And 12 more authors.
Journal of Animal Ecology | Year: 2010
The extent to which plant-herbivore feeding interactions are specialized is key to understand the processes maintaining the diversity of both tropical forest plants and their insect herbivores. However, studies documenting the full complexity of tropical plant-herbivore food webs are lacking. We describe a complex, species-rich plant-herbivore food web for lowland rain forest in Papua New Guinea, resolving 6818 feeding links between 224 plant species and 1490 herbivore species drawn from 11 distinct feeding guilds. By standardizing sampling intensity and the phylogenetic diversity of focal plants, we are able to make the first rigorous and unbiased comparisons of specificity patterns across feeding guilds. Specificity was highly variable among guilds, spanning almost the full range of theoretically possible values from extreme trophic generalization to monophagy. We identify guilds of herbivores that are most likely to influence the composition of tropical forest vegetation through density-dependent herbivory or apparent competition. We calculate that 251 herbivore species (48 of them unique) are associated with each rain forest tree species in our study site so that the ~200 tree species coexisting in the lowland rain forest community are involved in ~50 000 trophic interactions with ~9600 herbivore species of insects. This is the first estimate of total herbivore and interaction number in a rain forest plant-herbivore food web. A comprehensive classification of insect herbivores into 24 guilds is proposed, providing a framework for comparative analyses across ecosystems and geographical regions. © 2010 The Authors. Journal compilation © 2010 British Ecological Society.
Wallace H.M.,University of The Sunshine Coast |
Poienou M.,National Agriculture Research Institute |
Randall B.,University of The Sunshine Coast |
Moxon J.,National Agriculture Research Institute
Acta Horticulturae | Year: 2010
The genus Canarium (Burseraceae) contains approximately 100 species, mostly found in tropical Asia and the Pacific. In the Pacific, C. indicum is widely utilized for its edible nuts. Nuts are mostly traded fresh in roadside and village markets, in Papua New Guinea, the Solomon Islands and Vanuatu either as nut-inshell or as kernels. The Canarium industry, based on processed kernels, is in its infancy and has huge potential to improve the livelihood of the rural poor in these countries. We are investigating postharvest processing methods for C. indicum that are appropriate to Pacific Island countries. Our research is examining depulping, drying, cracking, testa removal, roasting and packaging methods. We have found that a 90 s hot water dip removes the testa on 85.8% of nuts without loss of whole kernels or increase in discolouration. We are also evaluating technology adapted from the macadamia industry for processing C. indicum and have found that a modified TJ's™ nutcracker has potential for efficient cracking of nuts. The cracker is portable, hand operated and suitable for use in Pacific Island countries for both small scale and commercial processing. Further research will examine processing technologies for larger scale processing such as mechanical depulpers, dryers and vacuum packaging.