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    Spiders as surrogate species in ecological monitoring, habitat classification and reserve selection : a thesis presented in partial fulfilment of the requirements for the degree of Masters of Science in Ecology at Massey University, Palmerston North, New Zealand
    (Massey University, 2001) Coombe, Gil Michael Ian
    The use of invertebrates in the monitoring of terrestrial ecosystems was investigated using spiders as a focal group. In a review of previous literature, spiders were found to meet the majority of criteria required of suitable ecological indicators, including high diversity and abundance, a widespread distribution, easy sampling and sorting, relatively low random fluctuation in population sizes and community composition, a range of dispersal abilities, measurable response to habitat change and representation of other taxa. The main weaknesses of spiders as ecological indicators were the lack of taxonomic expertise and sparse knowledge of baseline biology. However, these disadvantages could be rectified and it was concluded that spiders are suitable for further investigation as ecological indicators, involving field trials and hypothesis testing. The spider communities in the litter, herb and shrub layer of eight sites representing four habitat types within a forest successional series were sampled in Pouiatoa State Forest in Northern Taranaki. There were no distinct trends in spider richness or abundance across the successional series. However, spider species and family composition both reflected the successional stage from which they were taken. Site classifications using DCA and cluster analysis were similar when using either plant or spider data. Spider communities demonstrated potential for use in habitat classification of terrestrial ecosystems. Spiders and seven other ground-active invertebrate groups were sampled with pitfall traps from fourteen forest remnants within the Rangitikei Ecological Region to test whether spiders were able to act as indicators of plant and invertebrate diversity. Within-site richness (α-diversity) of spiders was strongly correlated with that of all other invertebrates combined, but spiders were not good predictors of between-site richness (²- diversity) of all other invertebrates. Correlation between the α- and β-diversities of plants and invertebrates were low, indicating that maximising plant diversity in reserve selection might not maximise invertebrate diversity. It is recommended that ground-active invertebrates be included in surveys of potential forest reserves. Spiders are a useful surrogate group for invertebrate communities and could be more widely used in the assessment, monitoring and management of terrestrial ecosystems.
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    Are aquatic invertebrates useful for assessing wetland condition? : a thesis presented in partial fulfilment of the requirements for the degree of Master of Environmental Management at Massey University, Manawatu, New Zealand
    (Massey University, 2017) Ekelund, Lovisa
    Freshwater wetlands are one of the most biodiverse ecosystems and at the same time of the most threatened globally. New Zealand has lost 90% of its wetlands and of those remaining, 60% are considered degraded. Establishing accurate wetland inventories and assessing wetland condition are priorities for the management and conservation of these important ecosystems. Aquatic invertebrates are used worldwide to assess the condition of other aquatic ecosystems such as rivers and lakes; however, their use for assessing wetland condition has not been extensive. A wetland’s hydroperiod is considered one of the most important environmental variables affecting wetland biota and one that has also been most altered by anthropogenic stresses. The second chapter of this thesis analyses the effect of hydroperiod on the macroinvertebrate communities of the Ō Tū Wharekai (Ashburton lakes) wetland system in New Zealand. A total of 40 taxa from 11 orders were recorded from 4 permanent lakes, 3 semi-permanent ponds, and 7 temporary ponds in September 2016. The macroinvertebrate assemblages in lakes were distinct to those in semi-permanent and temporary ponds. Overall, temporary ponds were slightly more diverse than the semipermanent ponds and lakes. Semi-permanent and temporary ponds were most similar to each other in macroinvertebrate composition. They host more species of small crustaceans such as cladocerans and ostracods, while species belonging to the Trichoptera, Odonata and Hirudinea orders were only present at permanent sites. The results emphasize the need to include small and seasonal wetlands in freshwater conservation efforts since they often hold unique biotic communities. In the third chapter, the potential to use macroinvertebrate communities in wetland assessment is evaluated. The macroinvertebrate communities of 14 freshwater wetlands in the lower North Island were sampled. The sites represent a gradient of wetland condition and include urban lagoons, agricultural swamps and lacustrine wetlands with recognized ecological value. A total of 63 invertebrate taxa were identified, of which crustaceans were the most abundant. There appeared to be no link between the composition and diversity of macroinvertebrate communities and wetland condition. However, of the habitat characteristics measured at each site, nutrient enrichment appeared to be the most important variable in determining macroinvertebrate assemblages. On the other hand, macrophyte communities appear to be more reflective of wetland condition. There are considerable knowledge gaps regarding invertebrate response to environmental change in freshwater wetlands and this limits their suitability as a biomonitoring tool. Assessing wetland condition accurately is one of the greatest challenges for the management and conservation of these threatened ecosystems. Aquatic invertebrates are used as biomonitoring tool for many freshwater ecosystems but not wetlands. This is because the way wetland invertebrates respond to environmental change remains unclear. So far, in New Zealand, there appears to be no link between wetland condition scores and invertebrate communities. Thus, the final section of this thesis proposes a simple dichotomous wetland condition scoring system exemplified with information from the 14 freshwater wetland sampled in the North Island. The method has limitations, but allows the integration of biotic data into wetland condition assessment.
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    Identification of a marker indicative of dairy faecal contamination in the environment : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science, Massey University, Palmerston North, New Zealand
    (Massey University, 2001) Harvey, Stephanie Adele
    Faecal contamination of aqueous environments remains a significant environmental problem. Faecal pollution causes degradation of both chemical and microbial water quality, exposing the public to a variety of pathogenic organisms. Contamination may originate from direct and indirect faecal sources. Direct sources of faecal contamination include piggery and dairy pond effluents, sewage, birds, bathers, or grazing animals with direct access to waterways. Indirect sources may comprise agricultural run-offs, or leaking septic tanks or sewage distribution systems. Discrimination of the origin of faecal contamination would enable monitoring agencies to predict associated disease risks more accurately, as well as implement strategies to mitigate the contaminating source. Escherichia coli, faecal coliforms and enterococci are extensively used as indicators of faecal pollution in water. These organisms are, however, widely distributed in the intestines of warm-blooded animals and hence enumeration does not define faecal origin. It has been suggested that bacterial strains may adapt to their environmental niche and consequently, host association of strains may be apparent. The development of highly discriminatory molecular fingerprinting techniques provides an opportunity to distinguish closely related strains. These techniques may be suitable for locating host associative factors and hence defining the source of faecal contamination. The scope the research described in this thesis was to develop a method capable of discriminating sources of faecal contamination in the environment. Agricultural faecal sources were primarily targeted as they represent a significant source of faecal contamination in New Zealand waterways. Two molecular fingerprinting techniques — Randomly Amplified Polymorphic DNA and Amplified Fragment Length Polymorphism — were investigated for their ability to detect genotypic markers in E. coli. A polymorphic fragment (714 bp) indicative of dairy cattle faecal isolates was identified by AFLP analysis. To facilitate rapid screening of isolates, PCR primers were designed to amplify a segment (462 bp) of the polymorphic fragment. The marker was specific for dairy cattle faecal isolates and was present in approximately half of the strains. Field study results demonstrated that the marker provided a feasible approach for monitoring "special interest" samples such as monitoring significant pollution incidences, supporting prosecution cases or identifying an illusive source of persistent water quality degradation at a particular site. In these instances the diagnostic marker may assist by verifying or eliminating suspected contaminating sources. AFLP analysis was used to locate a marker diagnostic of faecal origin, and indicated that further markers could be identified. Although RAPD-PCR analysis did not locate a diagnostic marker, the technique appeared to corroborate the AFLP results. The inability to obtain a highly specific marker using RAPD analysis may have been a function of the limited primer combinations that were screened. The AFLP technique could be used to construct a library of markers, enabling differentiation of a wide range of contaminating sources.