Climate change and dam development: Effects on wetland connectivity and ecological habitat in tropical wetlands

Abstract

Wetlands are one of the most threatened ecosystems on earth. Globally, there is growing demand to develop infrastructure to harvest water resources to support agriculture, threatening the ecological integrity of associated wetland ecosystems. We investigated the potential ecological impacts on floodplain wetland connectivity in northern Australia in response to changes in flow regime due to dam construction and climate change. Results for this study indicate that a drier climate and/or dam construction in catchments have the potential to reduce the effective size of the floodplain and reduce wetland connectivity. A drier climate will reduce rainfall and subsequent catchment run‐off, resulting in a decrease in the magnitude of riverine flows. In contrast, dams in the upper catchment will reduce the magnitude of flows downstream. The reduction in flows under both dam development and a drier climate will result in reduced extent and duration of floodplain inundation and decreased wetland connectivity. As a result, we anticipate that this loss of connectivity will reduce the capacity for nutrients, carbon and primary production to be flushed into the river channel, as well as reduce the ability for biota such as fish and turtles to move between in‐channel and off‐channel habitats.

Impact of water resource development on connectivity and primary productivity across a tropical river floodplain

“…Given the importance of algae and floodplain invertebrates to aquatic food webs (e.g. Jardine et al, 2013), productive wetlands need to be connected (Karim et al, 2015;Nielsen et al, 2020). An approach to measure connectivity across the entire floodplain landscape can build on these approaches to capture complex landscape-scale processes of connectivity (Mukherjee & Pal, 2021).…”

“…The use of graph theory provided the means to predict the impact of changes in floodplain inundation extent on ecosystem function, as measured by algal productivity. The integration of graph theoretic methods with algal productivity mapping enabled the development of a new set of ecological indicators, which provided information for ecosystem management based on the algal productivity in connected habitats and not merely the presence of surface water.Previous studies have analysed the impacts of changes to floodplain inundation on individual wetlands (Karim et al, 2015; Nielsen et al, 2020). An approach to measure connectivity across the entire floodplain landscape can build on these approaches to capture complex landscape‐scale processes of connectivity (Mukherjee & Pal, 2021).…”

“…Changes to floodplain land use and hydrology are likely to cause a loss of connectivity, which has been recognised as a considerable threat to the survival of many species across different ecosystems (Grande et al, 2020; Nielsen et al, 2020; Sala et al, 2000) including floodplain wetlands (Pettit et al, 2017). Water infrastructure, such as dams, can greatly alter the magnitude, frequency and duration of floods (Magilligan & Nislow, 2005), and thus increase habitat fragmentation and impair connectivity (Grill et al, 2015).…”

Metacommunity of a host metapopulation: explaining patterns and structures of a fish parasite metacommunity in a Neotropical floodplain basin

“…Our study highlights the need for implementing a metacommunity framework to understand the features that shape host-parasite interactions in freshwater parasite communities, following a growing literature (e.g., Richgels et al, 2013;Mihaljevic et al, 2018). Besides, floodplain ecosystems have been hugely threatened by the construction of dams and reservoirs (Nislow et al, 2002;Latrubesse et al, 2017;Nielsen et al, 2020), which can markedly modify the natural abiotic and biotic processes that shape species communities and fundamental ecological interactions, such as hostparasite dynamics.…”

Cladocera resting egg banks in temporary and permanent wetlands

“…For floodplain rivers, variability in riverine flows dictate the periods of connectivity between the river and associated floodplain wetlands and, in general, those wetlands lower on the floodplain will have more extended periods of connectivity and often retain permanent water compared to those wetlands further from the river that have shorter periods of connectivity and are often more temporary. The frequency of connection is dictated by the size of the river flow and extent of floodplain inundation (Nielsen et al, 2020). Connectivity between the river channel and wetlands promote dispersal of biota between wetlands.…”