Impacts of extreme events on southeastern Australian freshwater crayfish

Abstract

Extreme events like wildfire, flooding and drought, and activities related to managing these events (fire dam, bridge and road construction and water regulation) potentially impact freshwater crayfish populations, although limited information exists. Our study analysed abundance data for four freshwater crayfish species across an 11-year period, including pre-and post-wildfire and post-flooding data, and describes the impacts of human actions on their populations in the Grampians National Park in Victoria, Australia. Wildfire and flooding were generally associated with reduced crayfish abundances for Euastacus bispinosus, Cherax destructor, Geocharax falcata and Gramastacus insolitus, but in some habitats, C. destructor, G. falcata and G. insolitus did not decline. A general trend of decreasing abundances for all species was evident over the study period, likely due to the landscape-scale impacts of wildfire, flooding and the shrinking of available habitat during drought. Southeastern Australia is a crayfish biodiversity hot-spot and increased frequencies of wildfire, flooding and drought are forecast for this region as climate change progresses, threatening crayfish populations. Therefore, it is important that disaster recovery management seeks to minimise additional damage to crayfish habitat availability and connectivity. Copyright © 2014 by The Author(s). Published by the International Association of Astacology.This article is distributed under the terms of the Creative Commons Attribution License (CC-BY), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. A R T I C L E I N F O Freshwater CrayfishVolume 20, Number 1 altering habitat, which in turn may alter species distributions and the size and structure of populations through the frequency and severity of these events.

Direct and indirect impacts of wildfire on faunal communities of Mediterranean temporary ponds

“…However, in this study, the decreased abundance during the subsequent hydroperiod of organisms that aestivate in sediment may indicate direct burning or the effects of radiant heat on these animals while resting in the sediment during the dry periods (Cowell, Matthews, & Lind, 2006). Decreased abundances of specific groups after wildfire due to direct burning have been recorded for zooplankton in rice paddies and crayfish in streams and temporary wetlands (Chittapun, 2011;Johnston, Matthews, Robson, & Chester, 2014). Although other studies with less intense controlled burns detected no direct effect of fire on anostracan cysts (Wells, Hathaway, & Simovich, 1997).…”

“…While the taxonomic approach did not detect wildfire impacts, the functional approach detected stronger consequences of wildfire on all functional groups. Decreased abundances of specific groups after wildfire due to direct burning have been recorded for zooplankton in rice paddies and crayfish in streams and temporary wetlands (Chittapun, 2011;Johnston, Matthews, Robson, & Chester, 2014). Direct impacts of fire such as mortality (Gresswell, 1999) are commonly found in stream fishes and are associated with an increase in water temperatures or ammonia intoxication due to smoke diffusion (Beakes, Moore, Hayes, & Sogard, 2014;Isaak et al, 2010).…”

The conservation impacts of ecological disturbance: Time‐bound estimates of population loss and recovery for fauna affected by the 2019–2020 Australian megafires

“…Likewise, species differ in their capacity to recover from population loss due to differences in habitat and resource specificity, fecundity, and dispersal capacity. Although there is some evidence from previous studies of impacts of fire (e.g., Fox, 1982;Friend, 1993;Johnston et al, 2014;Lindenmayer et al, 2021;Loyn, 1997;Lyon & O'Connor, 2008;Westgate et al, 2018) there is limited or no information on the fire responses of most species, especially in relation to fires of the scale and severity of the 2019-2020 Australian megafires (Jolly, Dickman, et al, 2022;Pausas & Parr, 2018;Rowley et al, 2020).…”

Fire and rain: A systematic review of the impacts of wildfire and associated runoff on aquatic fauna

“…Ectothermic species tolerate thermal increases up to an upper limit, defined as the critical thermal maximum, after which further increases in temperature are lethal (Pörtner & Peck, 2010). Although the localized mortality of aquatic organisms is often reported following major wildfire events (Burton, 2005;Driessen, 2019;Johnston et al, 2014;Silva et al, 2020), this review found no evidence of direct mortality of aquatic fauna attributable to extreme water temperatures caused by wildfires. However, periods of warming during and after a fire could result in local extirpation of species if species-specific thermal limits are surpassed.…”