Resilience of trees and the vulnerability of grasslands to climate change in temperate Australian wetlands

Date

2021

Authors

Saintilan, Neil
Bowen, Sharon
Maguire, Owen
Karimi, Sara S.
Wen, Li
Powell, Megan
Colloff, Matthew
Sandi, S.
Saco, Patricia M
Rodriguez, J.

Journal Title

Journal ISSN

Volume Title

Publisher

Kluwer Academic Publishers

Abstract

Objectives: Observations from wetlands across the globe suggest a consistent pattern of woody encroachment into wetland grasslands, altering habitat structure and ecological function. The extent to which hydrological changes have contributed to woody invasion of wetland grasslands is unclear. Our objective was to compare rates of woody encroachment in Australian floodplain wetlands between wet and dry hydrological phases. We test the hypothesis that contraction of non-woody wetland vegetation (grasses and rushes) would be concentrated in dry phases, co-incident with recruitment of the River Red Gum Eucalyptuscamaldulensis lower in the floodplain. Methods: We conduct the first detailed mapping of habitat change in two of the largest forested wetlands in inland Australia, comparing wet and dry hydrological phases. Detailed photogrammetry, supported by extensive ground survey, allowed the interpretation of high resolution aerial photography to vegetation community level. Results: We found a consistent pattern of decline in non-woody vegetation, particularly amongst grasses utilising the C4 photosynthetic pathway. The C4 grasses Pseudoraphisspinescens and Paspalumdistichum showed steep declines in the Barmah Millewa and Macquarie Marshes respectively, being replaced by River Red Gum E. camaldulensis. C3 sedges proved more resilient in both systems. Conclusions: Our results suggest that a pattern of tree expansion into non-woody wetland vegetation, characteristic of wetlands across the globe, is a major habitat structural change in the Australian floodplain wetlands studied. Projected hydrological impacts of climate change are likely to further restrict wetland grass foraging habitat in these semi-arid floodplain wetlands.

Description

Keywords

Wetland, Woody encroachment, Canopy condition, Drought, Climate change

Citation

Source

Landscape Ecology

Type

Journal article

Book Title

Entity type

Access Statement

License Rights

DOI

10.1007/s10980-020-01176-5

Restricted until

2099-12-31