Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Accueil du site → Doctorat → Australie → 2019 → The influence of flooding on the vegetation of the semi-arid floodplain of the lower Lachlan River

University of Canberra (2019)

The influence of flooding on the vegetation of the semi-arid floodplain of the lower Lachlan River

Higgisson William

Titre : The influence of flooding on the vegetation of the semi-arid floodplain of the lower Lachlan River

Auteur : Higgisson William

Université de soutenance  : University of Canberra

Grade : Doctoral Thesis 2019

Résumé partiel
Floodplains are characterised by high biodiversity and productivity, providing habitat and refugia for a range of native species. These landscape features are also crucial for many aspects of human survival and quality of life. Inundation by flooding is the predominant factor that controls the observed ecological patterns and processes, and biological productivity on the floodplain. Semi-arid floodplains experience a highly variable flooding regime which has structured the vegetation communities. This thesis addresses some of the current gaps in our understanding of floodplain plants and their responses to water, on the semi-arid floodplain of the lower Lachlan River, Australia. It characterises spatial and temporal differences in seed bank characteristics relative to hydrological gradients, investigates the life-history responses of two floodplain shrub species (tangled lignum (Duma florulenta (Meisn.), and nitre goosefoot (Chenopodium nitrariaceum (F.Muell.)) to watering, and investigates gene-flow and population genetic structure in tangled lignum and river cooba (Acacia stenophylla (A. Cunn. ex Benth.)). This study is framed within the context of the changes in river floodplain connectivity caused by water resource development. I identified and compared the changes in floodplain-river connectivity characteristics that have occurred as a consequence of water resource development on four floodplain habitat types which occur on the lower Lachlan River, using a hydrological modelling approach. The results show that the floodplain of the lower Lachlan River connects to the river half as often under current flow conditions compared to flow conditions without water resource development. While all habitat types have been impacted by water resource development, the impact reduces away from the main channel of the river, with temporary floodplain lakes experiencing the largest change in connection regime and intermittent black box swamps which occur on the margins of floodplains experiencing the least.

Présentation

Version intégrale (4,4 Mb)

Page publiée le 22 mai 2021