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Community composition and distribution of macroinvertebrates on natural and artificial substrates in North Island lakes and ponds

Artificial structures in freshwater ecosystems are becoming increasingly common. The introduction of these structures in marine systems lead to changes in the physical structure and the biotic assemblages. Even though artificial structures provide hard substrates for species to colonize and settle on, they are commonly shown to support a smaller number of taxa than natural substrates and are also known to facilitate the settlement of disproportionate numbers of non-native species. Nevertheless, little is known of their effects in freshwaters. In the second chapter of my thesis, I compare macroinvertebrate communities on three substrate types, macrophytes, sediments and artificial structures, among twenty-two ponds, to identify differences in community composition and distribution of macroinvertebrates between natural and artificial substrates. In addition, I investigated whether non-native macroinvertebrates prefer artificial substrates more than natural substrates. The similarities between artificial substrates and macrophytes can be attributed to the habitat structure, i.e., hard surfaces and the provision of refugia for macroinvertebrates from their predators. The differences between sediments and macrophytes, and artificial substrates were attributed to the difference in habitat structure and the fauna they supported (i.e., sediments contained large proportions of infauna). Non-native species that were collected in my study did not show preference for any of the habitats that were sampled. In the third chapter of my thesis, I identified important environmental factors that affect the distribution of macroinvertebrates communities across the twenty-two ponds sampled. The most important factor identified was temperature, nutrient gradients, pH and dissolved oxygen levels. Both chapters of my thesis offer an understanding of how existing artificial substrates and environmental variables in lakes and ponds on the North Island, New Zealand, affect macroinvertebrate community composition and distribution in relation to natural substrates.
Type of thesis
Taitibe, H. (2019). Community composition and distribution of macroinvertebrates on natural and artificial substrates in North Island lakes and ponds (Thesis, Master of Environmental Sciences (MEnvSci)). The University of Waikato, Hamilton, New Zealand. Retrieved from https://hdl.handle.net/10289/12705
The University of Waikato
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