Identifying priority aquatic refuges to sustain freshwater biodiversity in intermittent streams in eastern Australia

Abstract

1. The hydrological variability of intermittent streams means that the spatial distribution of dry-season aquatic refuges within river networks and the temporal dynamics of hydrological connectivity between them are critical for the persistence of aquatic biodiversity. Here, a new approach is demonstrated to identify surface water bodies as priority refuges for efficient conservation management of freshwater biodiversity in intermittent stream networks.2. Recently developed models of surface water extent and daily streamflow were used to represent spatio-temporal variations in hydrological connectivity and surface water persistence within river networks of eastern Australia over a 107-yr period. Using this information, systematic conservation planning was applied to prioritize aquatic areas for conservation of 25 fish species under two scenarios.One scenario identified priority refuges to complement those already occurring in protected areas, whereas the other did not consider protected area status.3. The priority networks identified concentrated on the main stems of river catchments where surface water was more likely to be persistent and aquatic refuges were more likely to be connected, but also included headwaters for rare fish species. All three set conservation targets for the 25 fish species can be met in the best solution of priority networks. Although the second scenario achieved the targets with a smaller size of priority network overall, it required more new aquatic refuges and was thus less efficient than the first scenario.4. The newly developed datasets are useful for freshwater conservation prioritization because they account for hydrological variability of intermittent streams. The systematic prioritization approach applied is transferable to other regions and freshwater taxa to identify aquatic refuges for biodiversity conservation within intermittent stream systems.

Non-perennial segments in river networks

“…The deterioration or loss of these habitats, together with the lack of access to them due to fragmentation by anthropogenic barriers 134 , reduces fish populations which, in turn, affects subsistence fishers 52 . Therefore, management strategies for biodiversity conservation of entire river networks should prioritize the identification and protection of these refuges 135,136 .…”

“…In addition, effective network-scale conservation should seek to identify and protect key NPRs and their riparian zones. Systematic conservation planning tools such as Marxan 185 are powerful approaches for identifying priority sites acting as refuges for fish across entire river networks 135,136 , and for evaluating the conservation value of NPRs considering both their aquatic and terrestrial species 186 .…”

Integrating spatiotemporal hydrological connectivity into conservation planning to protect temporary rivers

“…TRs are one of the most widespread and vulnerable river systems on the planet (Chiu et al, 2017;Datry et al, 2023;Messager et al, 2021), but host unique freshwater biodiversity adapted to these ecosystems (e.g., Mesophylax, Tyrrhenoleuctra) (Bonada et al, 2020;Magoulick & Kobza, 2003;Vander Vorste et al, 2020;Yu et al, 2022).…”

“…TRs are one of the most widespread and vulnerable river systems on the planet (Chiu et al, 2017; Datry et al, 2023; Messager et al, 2021), but host unique freshwater biodiversity adapted to these ecosystems (e.g., Mesophylax , Tyrrhenoleuctra ) (Bonada et al, 2020; Magoulick & Kobza, 2003; Vander Vorste et al, 2020; Yu et al, 2022). In addition, TRs also support semi aquatic and terrestrial taxa (i.e., invertebrates and vertebrates) that use dry channels and riparian habitats as new habitats and migration corridors (Sánchez‐Montoya et al, 2017).…”

Analysing the contribution of intermittent rivers to beta diversity can improve freshwater conservation in Mediterranean rivers

“…Indeed, as the distribution of disconnected pools in IR networks can vary spatially and temporally from one year to another, tools have been developed to even account for their temporal and spatial occurrence (e.g. TRESH software; Gallart et al 2017), as well as to assess their priority as biodiversity refuges and incorporate them into conservation planning (Hermoso et al 2013;Yu et al 2022). Citizen science can also result in a powerful tool to fully understand the hydrological characteristics of these ecosystems (e.g.…”