Seasonal and Species Variation of the Hepatotoxin Indospicine in Australian Indigofera Legumes as Measured by UPLC−MS/MS

Livestock industries have maintained a keen interest in pasture legumes because of the high protein content and nutritive value. Leguminous Indigofera plant species have been considered as having high feeding values to be utilized as pasture, but the occurrence of the toxic constituent indospicine in some species has restricted this utility. Indospicine has caused both primary and secondary hepatotoxicosis and also reproductive losses, but has only previously been determined in a small number of Indigofera species. This paper validates a high throughput ultra-performance liquid chromatography−tandem mass spectrometry (UPLC−MS/MS) method to determine indospicine content of various Indigofera species found in Australian pasture. Twelve species of Indigofera together with Indigastrum parviflorum plants were collected and analysed. Out of the 84 samples analyzed, *I. spicata contained the highest indospicine level (1003 ± 328 mg/kg DM, n = 4) followed by I. linnaei (755 ± 490 mg/kg DM, n = 51). Indospicine was not detected in 9 of the remaining 11 species, and at only low levels (<10 mg/kg DM) in 2 out of 8 I. colutea specimens and in 1 out of 5 I. linifolia specimens. Indospicine concentrations were below quantitation levels for other Indigofera spp. (I. adesmiifolia, I. georgei, I. hirsuta, I. leucotricha,* I. oblongifolia, I. australis and I. trita) and Indigastrum parviflorum. One of the more significant findings to emerge from this study is that the indospicine content of I. linnaei is highly variable (159 to 2128 mg/kg DM, n = 51), and differs across both regions and seasons. Its first re-growth after spring rain has a higher (p < 0.01) indospicine content than growth following more substantial summer rain. The species collected include the predominant Indigofera in Australia pasture, and of these, only *I. spicata and I. linnaei contain high enough levels of indospicine to pose a potential toxic threat to grazing herbivores.

Increased reproductive success in older female red kangaroos and the impact of harvesting

Wildlife harvesting has a long history in Australia, including obvious examples of overexploitation. Not surprisingly, there is scepticism that commercial harvesting can be undertaken sustainably. Kangaroo harvesting has been challenged regularly at Administrative Appeals Tribunals and elsewhere over the past three decades. Initially, the concern from conservation groups was sustainability of the harvest. This has been addressed through regular, direct monitoring that now spans > 30 years and a conservative harvest regime with a low risk of overharvest in the face of uncertainty. Opposition to the harvest now continues from animal rights groups whose concerns have shifted from overall harvest sustainability to side effects such as animal welfare, and changes to community structure, genetic composition and population age structure. Many of these concerns are speculative and difficult to address, requiring expensive data. One concern is that older females are the more successful breeders and teach their daughters optimal habitat and diet selection. The lack of older animals in a harvested population may reduce the fitness of the remaining individuals; implying population viability would also be compromised. This argument can be countered by the persistence of populations under harvesting without any obvious impairment to reproduction. Nevertheless, an interesting question is how age influences reproductive output. In this study, data collected from a number of red kangaroo populations across eastern Australia indicate that the breeding success of older females is up to 7-20% higher than that of younger females. This effect is smaller than that of body condition and the environment, which can increase breeding success by up to 30% and 60% respectively. Average age of mature females in a population may be reduced from 9 to 6 years old, resulting in a potential reduction in breeding success of 3-4%. This appears to be offset in harvested populations by improved condition of females from a reduction in kangaroo density. There is an important recommendation for management. The best insurance policy against overharvest and unwanted side effects is not research, which could be never-ending. Rather, it is a harvest strategy that includes safeguards against uncertainty such as harvest reserves, conservative quotas and regular monitoring. Research is still important in fine tuning that strategy and is most usefully incorporated as adaptive management where it can address the key questions on how populations respond to harvesting.

Integrated pest management and supply chain improvement for mangoes in the Philippines and Australia

This project will incorporate two strategies for improving industry sustainability in the Philippines and Australia: (a) developing improved field management and quarantine monitoring and detection of mango pests and diseases; and (b) working with selected mango supply chains to identify and test areas for improvement.

Biological control of Mikania micrantha in Papua New Guinea and Fiji using the rust fungus Puccinia spegazzinii

Mikania micrantha Kunth (Asteraceae), commonly known as ‘mile-a-minute’, is a neotropical plant species now found in 17 Pacific island countries and territories, invading small cropping areas and plantations, thereby reducing productivity and food security. In 2006, a biocontrol project on M. micrantha commenced in Fiji and Papua New Guinea (PNG). The distribution of M. micrantha as well as baseline data such as plant growth rates and socio-economic impacts were determined before the importation of any biocontrol agents. Mikania micrantha was recorded in all 15 lowland provinces in PNG and on all major islands in Fiji. Plants grow about 3.2cm/day in PNG and about 1.9cm/day in Fiji. A socio-economic survey, involving over 370 respondents in over 220 villages from 15 provinces in PNG, found that 78% of respondents considered M. micrantha a serious weed and about 44% had M. micrantha, which they needed to weed at least fortnightly, in over a third of their land. Over 80% of respondents used slashing and/or handpulling as the preferred method of weed control. About 40% of respondents considered that M. micrantha reduced crop yield by more than 30%. In Fiji, 52 respondents from four islands participated in the survey. Over 60% of respondents in Fiji considered M. micrantha a serious weed and 23% had about 30% of their farm lands infested with the weed. Only 15% of respondents needed to weed at least fortnightly, with 56% using slashing and/or hand-pulling as the preferred means of control. Over 65% of respondents estimated that they lost at least 30% of potential crop yield to M. micrantha. Nearly 90% of respondents used M. micrantha as a medicinal plant to treat cuts and wounds. The life history of the rust Puccinia spegazzinii de Toni (Pucciniales: Pucciniaceae), originating from Ecuador, and imported into PNG and Fiji in 2008, was studied. P. spegazzinii is a microcyclic and autoecious rust and has a life cycle of 18-22 days. An efficient culturing and field release method was developed. Since 2008, the rust has been released at over 450 sites in 15 provinces in PNG, establishing at nearly 70 sites in four provinces. From some sites, the rust has spread over 7 km in 12 months. In Fiji, the rust has been released at over 80 sites, on four of the main islands, namely Viti Levu, Vanua Levu, Taveuni and Ovalau, and has established at 20 sites on Viti Levu and Vanua Levu. Plant growth studies and field monitoring in PNG showed that P. spegazzinii can significantly reduce the growth and density of M. micrantha and offers great potential for the control of this weed.

Monitoring wild pig populations: a review of methods

Wild pigs (Sus scrofa) are widespread across many landscapes throughout the world and are considered to be an invasive pest to agriculture and the environment, or conversely a native or desired game species and resource for hunting. Wild pig population monitoring is often required for a variety of management or research objectives, and many methods and analyses for monitoring abundance are available. Here, we describe monitoring methods that have proven or potential applications to wild pig management. We describe the advantages and disadvantages of methods so that potential users can efficiently consider and identify the option(s) best suited to their combination of objectives, circumstances, and resources. This paper offers guidance to wildlife managers, researchers, and stakeholders considering population monitoring of wild pigs and will help ensure that they can fulfill their monitoring objectives while optimizing their use of resources.

Biological and economic management strategy evaluations of the eastern king prawn fishery

Stock assessment of the eastern king prawn (EKP) fishery, and the subsequent advice to management and industry, could be improved by addressing a number of issues. The recruitment dynamics of EKP in the northern (i.e., North Reef to the Swain Reefs) parts of the fishery need to be clarified. Fishers report that the size of the prawns from these areas when they recruit to the fishing grounds is resulting in suboptimal sizes/ages at first capture, and therefore localised growth overfishing. There is a need to assess alternative harvest strategies of the EKP fishery, via computer simulations, particularly seasonal and monthly or lunar-based closures to identify scenarios that improve the value of the catch, decrease costs and reduce the risk of overfishing, prior to implementing new management measures.