Urbanisation and environmental modification as drivers of insect community diversity and composition in Sydney, Australia / Urbanización y modificación ambiental como promotores de la diversidad y composición de comunidades de insectos en Sídney, Australia

Insects are essential for the functioning of ecosystems, delivering important ecological functions as nutrient recycling, pest control, pollination, and seed dispersal. Biodiversity increases the multi-functionality and resilience of ecosystems around the world, a valuable effect considering that gl...

Descripción completa

Detalles Bibliográficos
Autor Principal: Lequerica Támara, Manuel
Formato: Trabajo de grado (Bachelor Thesis)
Lenguaje:Desconocido (Unknown)
Publicado: 2017
Materias:
Acceso en línea:http://babel.banrepcultural.org/cdm/ref/collection/p17054coll23/id/1055
Descripción
Sumario:Insects are essential for the functioning of ecosystems, delivering important ecological functions as nutrient recycling, pest control, pollination, and seed dispersal. Biodiversity increases the multi-functionality and resilience of ecosystems around the world, a valuable effect considering that global change is likely to have an impact on ecosystems globally. In the process of urbanisation, ecosystems are modified and plant and animal communities segregated, affecting biodiversity and thus jeopardising ecosystems in a global scale. Different insect taxa play distinct ecological roles, so assessing how environmental factors associated with urbanisation affect them is relevant for the conservation of biological diversity of cities. The main objective of this research project was to investigate how insect communities are affected by urbanisation, using an integrated multi-taxa and multiscale approach. The research project is divided in two fundamental questions: 1) Are insect communities affected by coarse or fine scale environmental filters? and 2) Are insect´s foraging abilities affected by environmental modification? To address the first question, I sampled four insect taxa (Coleoptera, Diptera, Hemiptera and Hymenoptera) in 19 sites with three levels of environmental modification, and multiple environmental variables associated with urbanisation. For the second question, I used focal plants to sample floral visitors in 19 sites with varying levels of environmental modification, recording the time taken for the focal plant to be discovered by an insect, and the number of insects after 48 hours. My results show that coarse environmental filters affect Hemiptera communities but do not seem to affect Coleoptera, Diptera, or Hymenoptera communities. Fine environmental filters such as proportion of native plants with flowers, site area, and proportion of green space are associated with species richness of coleopteran, dipteran and hymenopteran communities. Floral discoverability was not associated with environmental modification but the number of insects was higher in sites with higher environmental modification. Native floral resources are important for the maintenance of urban biodiversity, thus native plants should be used in urban green. Low species richness of hymenopterans and coleopterans in more urbanised sites indicates the susceptibility of these groups to urbanisation, reflecting what others studies have found in urban contexts worldwide. Environmental modification affects insects’ ability to discover and use floral resources. Where conservation initiatives use floral resource plantings to support biodiversity, environmental modification must be considered, to ensure that target taxa are able to reach the novel resources.