Improving the success of insect conservation translocations: a case study of the nationally endangered robust grasshopper (brachaspis robustus bigelow)
The current rates of species loss and decline are so extraordinary that the Earth is speculated to be on the cusp of entering a sixth mass extinction, with the majority of species lost expected to be insects. Insects make up approximately 70 % of all species on Earth and are proportionally the most...
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| Format: | Other/Unknown Material |
| Language: | English |
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University of Canterbury
2020
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| Online Access: | http://hdl.handle.net/10092/18616 https://doi.org/10.26021/6885 |
| Summary: | The current rates of species loss and decline are so extraordinary that the Earth is speculated to be on the cusp of entering a sixth mass extinction, with the majority of species lost expected to be insects. Insects make up approximately 70 % of all species on Earth and are proportionally the most under- represented class of animal in conservation biology. An important tool for substantially reducing the risk of extinction for critically threatened species is conservation translocation, which is defined by the International Union for Conservation of Nature as “the intentional movement and release of a living organism where the primary objective is a conservation benefit”. However, there has been limited applications of translocation as a conservation tool for insects, and only 52 % of terrestrial insect translocations are reported as successful at establishing a persistent population. This thesis develops applied conservation management strategies to improve translocation success for insects using New Zealand’s Nationally Endangered robust grasshopper, Brachaspis robustus Bigelow (Orthoptera: Acrididae), as a case study. Brachaspis robustus is a large bodied, flightless, highly visually cryptic and non-stridulating grasshopper. It is a braided river specialist endemic to the Mackenzie Basin, an inter-montane dryland region in the centre of New Zealand’s South Island. Currently all wild populations of B. robustus that are monitored by the New Zealand Department of Conservation show trends of decline. Despite being one of New Zealand’s most threatened grasshopper species, little research has been directed toward maximising conservation outcomes for B. robustus. The first objective of this research was to understand the life history of B. robustus. Grasshoppers were tracked from egg to adulthood in captivity in the field and in the laboratory. The life cycle of B. robustus was observed to be ~27 months in the field. Females laid on average 1.3 egg pods in the wild, but up to 8 in the laboratory. Egg pods contained ... |
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