Current State and Reassessment of Threatened Species Status of Invertebrates Endemic to Great Artesian Basin Springs Renee A. Rossini1 Abstract Springs are unusual freshwater ecosystems of high cultural and conservation significance, yet they are often overlooked in discussions of global freshwater biodiversity, ecology and conser- vation. Springs that emerge from the Great Artesian Basin (GAB) in Australia support a high diversity of endemic aquatic species. The majority of these species are at high risk of extinc- tion due to their small geographic ranges, severe habitat loss and ongoing threats. However, the ecological requirements of most spring biota are poorly understood and the majority are unprotected, particularly invertebrates, for which basic taxonomic and ecological information is lacking for numerous species. This assessment of threat status determined that 98% of molluscs and 80% of crustaceans endemic to GAB springs meet the criteria for designation of ‘critically endangered’ under the Australian Environment Protection and Biodiversity Conservation Act 1999 (Cth) (the EPBC Act). However, none of these species is currently listed. The analyses in this paper provide support for individual EPBC listing of all species of gastropods and crustaceans. Keywords: springs, invertebrates, endemic species, threats to springs, conservation status, Great Artesian Basin 1 The University of Queensland, St Lucia, QLD 4067, Australia Introduction but those in arid regions are particularly important Freshwater environments are amongst the most because they provide a reliable source of water in altered and under-conserved global ecosystems, areas characterised by water scarcity and imperma- despite being ‘hotspots’ of cultural significance and nence (Davis et al., 2013, 2017). They act as ‘islands’ endemic diversity (Geist, 2011; Strayer & Dudgeon, of hospitable wetlands in a ‘sea’ of aridity (Ponder, 2010). Freshwater environments that depend on 1995) that are used as watering points for broadly groundwater, such as springs, are particularly vul- distributed species, as well as providing criti- nerable because increasing water demands are cal wetland environments for suites of organisms leading to significant anthropogenic alteration of the endemic to springs (Fensham et al., 2011; Myers & groundwater sources that sustain them (Cantonati et Resh, 1999). Extensive spring systems are present in al., 2012; El-Saied et al., 2015; Fairfax & Fensham, the arid and semi-arid regions of most continents, 2002; Famiglietti, 2014; Kreamer & Springer, 2008; with each region sharing parallel stories of unique Nevill et al., 2010; Powell et al., 2015; Stevens features, fragility, threat and destruction (Powell & & Meretsky, 2008; Unmack & Minckley, 2008). Fensham, 2016; Unmack & Minckley, 2008). Despite the pertinent threats springs face, they are Arid zone springs fed by the Australian Great rarely included in global assessments of freshwater Artesian Basin (GAB) have been a focus of both biodiversity, ecology or conservation (Cantonati et Indigenous and colonial use because they provide a al., 2012). Springs are unique and diverse fresh water reliable source of water in prevailingly dry portions ecosystems that emerge in a range of landscapes, of the continent. The chain of GAB springs that This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International Licence. Individual articles may be copied or downloaded for private, scholarly and not-for-profit use. Quotations may be extracted provided that the author and The Royal Society of Queensland are acknowledged. Queries regarding republication of papers, or parts of papers such as figures and photographs, should be addressed to the Secretary of The Royal Society of Queensland ([email protected]). PROCEEDINGS OF THE ROYAL SOCIETY OF QUEENSLAND VOL. 126 225 226 RENEE A. ROSSINI extends from Kati Thanda–Lake Eyre to north- fish) consume or compete with species endemic to east Queensland forms vital points in the lore springs, in some cases to the point of near extinction and song-lines of numerous First Peoples (Harris, (Kerezsy & Fensham, 2013). Although the exces- 2002; Potezny, 1989), and springs remain impor- sive drawdown associated with unchecked water tant sources of material and spiritual inspiration for extraction from the GAB has been ameliorated by traditional custodians (Ah Chee, 1995; Moggridge, programs such as GABSI, risky extraction licenses 2020). Springs facilitated the occupancy and stock- are still being granted (Currell, 2016; Currell et al., ing of the arid interior during the early colonial 2017) and these additional threatening processes period, and by 1895, water inspectors docu mented continue to affect the unique biodiversity that exists the use and alteration of many Queensland springs in GAB springs. (Fairfax & Fensham, 2002; Powell et al., 2015). Relative few of the species currently described Physical alteration of springs and extraction of as endemic to GAB springs have been the subject of water from the GAB using bores drastically detailed published accounts regarding their distri- increased with agricultural intensification, lead- bution, population numbers and ecology. For those ing to increased extraction volumes and decreased species for which detailed population and distri- water pressure within the GAB. This caused a bution data are available, it appears common for large proportion of springs to become dormant species to be restricted to a single spring complex, or (Fairfax & Fensham, 2002; Powell et al., 2015). numerous complexes in the same locality (Fensham The loss of GAB springs is of concern because of et al., 2011). Populations of species endemic to the their extremely high biologi cal and cultural values, GAB spring wetlands are rarely found in all springs and because their demise is a sign of the broader within an occupied complex, and the particu- issue of diminished pressure in the aquifer at large. lar springs occupied tend to change through time Nation-wide schemes to regain GAB pressure by (Fensham & Fairfax 2002; Kerezsy & Fensham, capping bores have been enacted (e.g. the GAB 2013; Ponder et al., 1989; Worthington-Wilmer Sustainability Initiative (GABSI); Brake, 2020). et al., 2008). Extirpations in a single spring seem Discharge springs that survived the initial relatively common over decadal time scales, but broad-scale habitat loss post-1890 remain exposed species can persist within their broader geographic to a range of threatening processes (Davis et al., range due to the presence of an ever-shifting set 2017). Continued extraction of water from the GAB of viable populations (Worthington-Wilmer et al., creates further pressure loss, leading to the extinc- 2011). These patterns of spring occupancy appear to tion of springs and populations of endemic species vary across species, with different species occupy- that occupy them (Mudd, 2000), or the permanent ing different sets of springs and displaying different alteration of spring chemistry (Shand et al., 2013). patterns of population connectivity (Murphy et al., Industries with high water demands (e.g. mining 2010). Consequently, some springs are more diverse and intensive agriculture) magnify this threat, and (Kodric-Brown & Brown, 1993; Ponder et al., 1989) models of how these threats will affect springs and or maintain populations over longer periods, whilst their biodiversity provide limited predictions at others host only one particular species for a short best (Mudd, 2000). Springs that survive drawdown time (Worthington-Wilmer et al., 2011). As small remain exposed to introduced species. Introduced geographic range appears to be the norm, it is prob- plants and nutrient-led changes to the dynamics able that severe biodiversity losses accompanied the of native species mean that some species grow to broad-scale loss of springs that occurred post-1890 dominate springs (e.g. Holmquist et al., 2011) and (Fensham et al., 2010). Habitat loss that has not can diminish the spring pools vital to the persis- led to extinction is still associated with the loss of tence of aquatic animals (Kodric-Brown & Brown, genetic diversity (Faulks et al., 2017) and the poten- 2007; Lewis & Packer, 2020). Ungulates trample tial loss of cryptic species or clades before they are springs, with pigs being particularly destructive as discovered or described (Mudd, 2000). they actively uproot vegetation (Kovac & Mackay, Despite the unique nature of GAB springs, 2009). Invasive aquatic fauna living within the and the severity of the threats they face, these springs (including invertebrates, amphibians and wetlands have only recently attracted state and THREATENED ENDEMIC INVERTEBRATES OF GREAT ARTESIAN BASIN SPRINGS 227 Commonwealth conservation attention, although individually as threatened species under EPBC they were cared for previously under cus tomary legislation. systems (Moggridge, 2020). The flora and fauna Lack of attention to invertebrates that are at risk associated with springs came under Commonwealth of extinction in springs is representative of a global protection in 2001, via a blanket listing of “the trend that hinders conservation efforts in fresh- community of native species dependent on natural water systems (Bland et al., 2012; Cardoso et al., discharge of groundwater from the GAB” as ‘endan- 2011; Strayer, 2006). In Australia, populations of gered’ under the Environment Protection and some of the most restricted and threatened inver- Biodiversity