Floodplain ecosystem dynamics under extreme dry and wet phases in semi-arid Australia

Gilad Bino, Skye Wassens, Richard T. Kingsford, Rachael Thomas, Jennifer Spencer

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Ecological networks are a cornerstone of ecological theory, offering an integrated approach to understanding food webs and ecosystem dynamics required for restoration and conservation ecology.
We investigated ecological network dynamics in a large floodplain undergoing extreme variation in water availability, with drought and subsequent flooding representing a resource pulse. We used structural equation models to quantify ecological network dynamics for the Lowbidgee floodplain (Australia), based on surveys over 5 years while the floodplain transitioned from extremely dry (2009, 2010) to wet (2011) and post-wet (2013, 2014) conditions.
We identified significant associations of species and trophic guilds with inundation at the site and floodplain scale, which allowed us to quantify the strength of biotic interactions within the network and the stability of interactions under differing patterns of resource availability. At the floodplain scale, most taxa responded strongly in distribution and abundance to the 2011 resource pulse, a widespread flood, but this response did not persist during subsequent years of moderate floods. In contrast, fish species, both native and exotic, responded strongly only in the post-wet period. At the fine spatial scale (i.e., sites), complex responses were observed, with only waterbirds, frogs and tadpoles positively associated with inundation, while fish species showed a range of associations with fine-scale inundation. Biotic interactions within sites, across all trophic guilds, were predominately overridden by inundation and water temperature, mediated by strong associations with aquatic vegetation.
Stratifying the ecological network to dry, wet and post-wet periods highlighted varying associations of taxa with fine-scale inundation, generally responding synchronously to resource pulses, with relatively weak biotic interactions. Associations with site-scale inundation were strongest during the post-wet period for fishes and frogs. Only Litoria spp. (Hylidae) tadpoles, waterbirds and aquatic vegetation had positive associations with site-scale inundation during the dry period.
We conclude that responses of trophic guilds are largely dependent on the way they interact with their environment at particular spatial and temporal scales. Our investigation of this ecological network reinforced the importance of hydrological drivers over biotic interactions, with clear implications for the management of environmental flows, particularly in systems recovering from long-term flow alteration. Management efforts should focus environmental flows to promote specialist species (e.g., southern bell frog, Litoria raniformis) and Murray hardyhead (Craterocephalus fluviatilis: Atherinidae), waterbirds and aquatic vegetation over the more generalist fish species that have established because of the loss of the natural flow regime.
Original languageEnglish
Pages (from-to)224-241
Number of pages18
JournalFreshwater Biology
Volume63
Issue number2
Early online dateDec 2017
DOIs
Publication statusPublished - Feb 2018

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ecosystem dynamics
floodplains
floodplain
water birds
aquatic plants
guild
ecosystems
frog
fish
tadpoles
frogs
vegetation
resource
Atherinidae
ecological theory
Hylidae
environmental management
resource availability
integrated approach
generalist

Cite this

@article{991eabf4cfca4a708658bff2c66caf8b,
title = "Floodplain ecosystem dynamics under extreme dry and wet phases in semi-arid Australia",
abstract = "Ecological networks are a cornerstone of ecological theory, offering an integrated approach to understanding food webs and ecosystem dynamics required for restoration and conservation ecology.We investigated ecological network dynamics in a large floodplain undergoing extreme variation in water availability, with drought and subsequent flooding representing a resource pulse. We used structural equation models to quantify ecological network dynamics for the Lowbidgee floodplain (Australia), based on surveys over 5 years while the floodplain transitioned from extremely dry (2009, 2010) to wet (2011) and post-wet (2013, 2014) conditions.We identified significant associations of species and trophic guilds with inundation at the site and floodplain scale, which allowed us to quantify the strength of biotic interactions within the network and the stability of interactions under differing patterns of resource availability. At the floodplain scale, most taxa responded strongly in distribution and abundance to the 2011 resource pulse, a widespread flood, but this response did not persist during subsequent years of moderate floods. In contrast, fish species, both native and exotic, responded strongly only in the post-wet period. At the fine spatial scale (i.e., sites), complex responses were observed, with only waterbirds, frogs and tadpoles positively associated with inundation, while fish species showed a range of associations with fine-scale inundation. Biotic interactions within sites, across all trophic guilds, were predominately overridden by inundation and water temperature, mediated by strong associations with aquatic vegetation.Stratifying the ecological network to dry, wet and post-wet periods highlighted varying associations of taxa with fine-scale inundation, generally responding synchronously to resource pulses, with relatively weak biotic interactions. Associations with site-scale inundation were strongest during the post-wet period for fishes and frogs. Only Litoria spp. (Hylidae) tadpoles, waterbirds and aquatic vegetation had positive associations with site-scale inundation during the dry period.We conclude that responses of trophic guilds are largely dependent on the way they interact with their environment at particular spatial and temporal scales. Our investigation of this ecological network reinforced the importance of hydrological drivers over biotic interactions, with clear implications for the management of environmental flows, particularly in systems recovering from long-term flow alteration. Management efforts should focus environmental flows to promote specialist species (e.g., southern bell frog, Litoria raniformis) and Murray hardyhead (Craterocephalus fluviatilis: Atherinidae), waterbirds and aquatic vegetation over the more generalist fish species that have established because of the loss of the natural flow regime.",
keywords = "Ecological network, Food web, Resource pulse, Structural equation model, Wetlands",
author = "Gilad Bino and Skye Wassens and Kingsford, {Richard T.} and Rachael Thomas and Jennifer Spencer",
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Floodplain ecosystem dynamics under extreme dry and wet phases in semi-arid Australia. / Bino, Gilad; Wassens, Skye; Kingsford, Richard T.; Thomas, Rachael; Spencer, Jennifer.

In: Freshwater Biology, Vol. 63, No. 2, 02.2018, p. 224-241.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Floodplain ecosystem dynamics under extreme dry and wet phases in semi-arid Australia

AU - Bino, Gilad

AU - Wassens, Skye

AU - Kingsford, Richard T.

AU - Thomas, Rachael

AU - Spencer, Jennifer

N1 - Includes bibliographical references.

PY - 2018/2

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N2 - Ecological networks are a cornerstone of ecological theory, offering an integrated approach to understanding food webs and ecosystem dynamics required for restoration and conservation ecology.We investigated ecological network dynamics in a large floodplain undergoing extreme variation in water availability, with drought and subsequent flooding representing a resource pulse. We used structural equation models to quantify ecological network dynamics for the Lowbidgee floodplain (Australia), based on surveys over 5 years while the floodplain transitioned from extremely dry (2009, 2010) to wet (2011) and post-wet (2013, 2014) conditions.We identified significant associations of species and trophic guilds with inundation at the site and floodplain scale, which allowed us to quantify the strength of biotic interactions within the network and the stability of interactions under differing patterns of resource availability. At the floodplain scale, most taxa responded strongly in distribution and abundance to the 2011 resource pulse, a widespread flood, but this response did not persist during subsequent years of moderate floods. In contrast, fish species, both native and exotic, responded strongly only in the post-wet period. At the fine spatial scale (i.e., sites), complex responses were observed, with only waterbirds, frogs and tadpoles positively associated with inundation, while fish species showed a range of associations with fine-scale inundation. Biotic interactions within sites, across all trophic guilds, were predominately overridden by inundation and water temperature, mediated by strong associations with aquatic vegetation.Stratifying the ecological network to dry, wet and post-wet periods highlighted varying associations of taxa with fine-scale inundation, generally responding synchronously to resource pulses, with relatively weak biotic interactions. Associations with site-scale inundation were strongest during the post-wet period for fishes and frogs. Only Litoria spp. (Hylidae) tadpoles, waterbirds and aquatic vegetation had positive associations with site-scale inundation during the dry period.We conclude that responses of trophic guilds are largely dependent on the way they interact with their environment at particular spatial and temporal scales. Our investigation of this ecological network reinforced the importance of hydrological drivers over biotic interactions, with clear implications for the management of environmental flows, particularly in systems recovering from long-term flow alteration. Management efforts should focus environmental flows to promote specialist species (e.g., southern bell frog, Litoria raniformis) and Murray hardyhead (Craterocephalus fluviatilis: Atherinidae), waterbirds and aquatic vegetation over the more generalist fish species that have established because of the loss of the natural flow regime.

AB - Ecological networks are a cornerstone of ecological theory, offering an integrated approach to understanding food webs and ecosystem dynamics required for restoration and conservation ecology.We investigated ecological network dynamics in a large floodplain undergoing extreme variation in water availability, with drought and subsequent flooding representing a resource pulse. We used structural equation models to quantify ecological network dynamics for the Lowbidgee floodplain (Australia), based on surveys over 5 years while the floodplain transitioned from extremely dry (2009, 2010) to wet (2011) and post-wet (2013, 2014) conditions.We identified significant associations of species and trophic guilds with inundation at the site and floodplain scale, which allowed us to quantify the strength of biotic interactions within the network and the stability of interactions under differing patterns of resource availability. At the floodplain scale, most taxa responded strongly in distribution and abundance to the 2011 resource pulse, a widespread flood, but this response did not persist during subsequent years of moderate floods. In contrast, fish species, both native and exotic, responded strongly only in the post-wet period. At the fine spatial scale (i.e., sites), complex responses were observed, with only waterbirds, frogs and tadpoles positively associated with inundation, while fish species showed a range of associations with fine-scale inundation. Biotic interactions within sites, across all trophic guilds, were predominately overridden by inundation and water temperature, mediated by strong associations with aquatic vegetation.Stratifying the ecological network to dry, wet and post-wet periods highlighted varying associations of taxa with fine-scale inundation, generally responding synchronously to resource pulses, with relatively weak biotic interactions. Associations with site-scale inundation were strongest during the post-wet period for fishes and frogs. Only Litoria spp. (Hylidae) tadpoles, waterbirds and aquatic vegetation had positive associations with site-scale inundation during the dry period.We conclude that responses of trophic guilds are largely dependent on the way they interact with their environment at particular spatial and temporal scales. Our investigation of this ecological network reinforced the importance of hydrological drivers over biotic interactions, with clear implications for the management of environmental flows, particularly in systems recovering from long-term flow alteration. Management efforts should focus environmental flows to promote specialist species (e.g., southern bell frog, Litoria raniformis) and Murray hardyhead (Craterocephalus fluviatilis: Atherinidae), waterbirds and aquatic vegetation over the more generalist fish species that have established because of the loss of the natural flow regime.

KW - Ecological network

KW - Food web

KW - Resource pulse

KW - Structural equation model

KW - Wetlands

U2 - 10.1111/fwb.13056

DO - 10.1111/fwb.13056

M3 - Article

VL - 63

SP - 224

EP - 241

JO - Freshwater Biology

JF - Freshwater Biology

SN - 0046-5070

IS - 2

ER -