Invertebrates are an often overlooked but vital component of healthy ecosystems. They perform a variety of critical ecological functions and ecosystem services, including pollination, soil modification, organic matter decomposition, nutrient cycling, pest control, and food provisioning to other animals and humans (Lavelle et al. 2006; Macadam and Stockan 2015; Griffiths et al. 2021; Porto et al. 2021). They are ubiquitous across land and seascapes, constituting the vast majority of Earth’s biodiversity. Over 1.25 million invertebrate species have been documented, representing around 95% of animal species (Eisenhauer and Hines 2021). However, many invertebrate species and populations around the globe are under threat, as are the services they provide and the ecosystems they support (Hallmann et al. 2017; Ulrich et al. 2020; Wagner et al. 2021; Eisenhauer et al. 2023).
Australia has a high proportion of endemic fauna and is home to around 320,000 invertebrate species, of which around 35% have been described (Murphy and Leeuwen 2021). These include invertebrates of cultural significance to Indigenous Australians, such as freshwater crayfish (marron), beetle larvae (witchetty grubs), and Bogong moths, used for food, medicine, and ceremonies for thousands of years (Faast and Weinstein 2020; Stephenson et al. 2020; Murphy and Leeuwen 2021). Invertebrates also play vital roles in Australian agriculture, land management, and environmental monitoring (Andersen and Majer 2004; Holloway, Furlong, and Bowden 2008). Despite their ecological, cultural, social, and economic importance, invertebrates are often neglected in conservation and management plans, and a lack of taxonomic and ecological knowledge hinders their protection (Braby 2018, 2019; Sands 2018). Invertebrates constitute 95% of Australia’s faunal diversity but only 15% of species assessed under the Environment Protection and Biodiversity Conservation Act (EPBC Act), and only around 480 species of Australian invertebrates are listed as threatened (invertebratesaustralia.org).
Invertebrates face a multitude of anthropogenic and environmental threats, including habitat loss, climate change (and associated events such as fires, floods, and droughts), pollution, pesticides, and introduced species (Wagner et al. 2021; Marsh et al. 2022; Reddin et al. 2022). There is growing evidence that such pressures, which have seen widespread invertebrate declines around the globe, are impacting Australian species (Braby, Yeates, and Taylor 2021). While there is an urgent need for further research on invertebrate biodiversity and conservation in relation to these threats, conservation measures can help to mitigate their effects, protect and restore biodiversity, and prevent extinctions.
Biological conservation is hampered by limited resources, and identifying priority areas to focus conservation efforts can help to maximise their effectiveness (Myers et al. 2000). Species richness and endemism are key indices of biodiversity that reflect biological complexity and uniqueness, and can be used to identify ‘biodiversity hotspots’ to prioritise for conservation (Myers 1988; Caldecott et al. 1996; Reid 1998). Species richness refers to the number of species in an area. Numerous definitions of endemism exist but generally a taxon is considered endemic to a particular area if it occurs only in that area (Anderson 1994). Quantifying endemism and identifying areas of high endemism is important in conservation because narrowly endemic taxa have small ranges by definition and are therefore more vulnerable to threats such as habitat loss and climate change (Harvey et al. 2011). The 10 known invertebrate extinctions in Australia were all narrow-range endemics (Braby 2019). There is a need to identify hotspots of invertebrate biodiversity to enhance their conservation, particularly within Australia (Taylor et al. 2018). Designation of protected areas and other landscape management practices can be informed by spatial quantification of endemism. Identifying hotspots helps to focus limited resources and improve the efficiency of biodiversity conservation efforts.
Identifying hotspots for all invertebrates is not logistically feasible at present, so as a proof of concept we focussed on spiders in the infraorder Mygalomorphae, using spatial analyses to identify hotspots of species richness and endemism across Australia. Mygalomorph spiders have poor dispersal capabilties and sedentary habits, making them well-suited to endemism analyses (Ferretti, González, and Pérez–Miles 2014). Australian mygalomorphs are diverse and many may face a greater level of threat than what is formally recognised (Castalanelli et al. 2014; Rix et al. 2017). Our methods can be used as a framework and extended to other taxonomic groups. Identifying hotspots of endemism in the Australian invertebrate fauna will help guide research and conservation efforts and improve outcomes, not only for invertebrates, but for the ecological communities they support.
(to move to methods) Quantification of endemism depends on the spatial scale being considered (Townsend Peterson and Watson 1998), and numerous calculation methods exist (). Endemism can be quantified on a continuous scale across a spatial grid with reference to the constituent grid cells, based on how many cells taxa occupy.
Andersen, Alan N., and Jonathan D. Majer. 2004.
“Ants Show the Way down Under: Invertebrates as Bioindicators in Land Management.” Journal Article.
Frontiers in Ecology and the Environment 2 (6): 291–98. https://doi.org/
https://doi.org/10.1890/1540-9295(2004)002[0292:ASTWDU]2.0.CO;2.
Anderson, Sydney. 1994.
“Area and Endemism.” The Quarterly Review of Biology 69 (4): 451–71.
https://doi.org/10.1086/418743.
Braby, Michael F. 2018.
“Threatened Species Conservation of Invertebrates in Australia: An Overview.” Journal Article.
Austral Entomology 57 (2): 173–81. https://doi.org/
https://doi.org/10.1111/aen.12324.
———. 2019.
“Are Insects and Other Invertebrates in Decline in Australia?” Journal Article.
Austral Entomology 58 (3): 471–77. https://doi.org/
https://doi.org/10.1111/aen.12411.
Braby, Michael F., David K. Yeates, and Gary S. Taylor. 2021.
“Population Declines and the Conservation of Insects and Other Terrestrial Invertebrates in Australia.” Journal Article.
Austral Entomology 60 (1): 3–8. https://doi.org/
https://doi.org/10.1111/aen.12519.
Caldecott, J. O., M. D. Jenkins, T. H. Johnson, and B. Groombridge. 1996.
“Priorities for Conserving Global Species Richness and Endemism.” Journal Article.
Biodiversity & Conservation 5 (6): 699–727.
https://doi.org/10.1007/BF00051782.
Castalanelli, Mark A., Roy Teale, Michael G. Rix, W. Jason Kennington, and Mark S. Harvey. 2014.
“Barcoding of Mygalomorph Spiders (Araneae : Mygalomorphae) in the Pilbara Bioregion of Western Australia Reveals a Highly Diverse Biota.” Journal Article.
Invertebrate Systematics 28 (4): 375–85.
https://doi.org/10.1071/IS13058.
Eisenhauer, Nico, and Jes Hines. 2021. “Invertebrate Biodiversity and Conservation.” Current Biology 31 (19): R1214–18.
Eisenhauer, Nico, Raúl Ochoa-Hueso, Yuanyuan Huang, Kathryn E Barry, Alban Gebler, Carlos A Guerra, Jes Hines, Malte Jochum, Karl Andraczek, and Solveig Franziska Bucher. 2023. “Ecosystem Consequences of Invertebrate Decline.” Journal Article. Current Biology 33 (20): 4538–4547. e5.
Faast, Renate, and Philip Weinstein. 2020.
“Plant-Derived Medicinal Entomochemicals: An Integrated Approach to Biodiscovery in Australia.” Journal Article.
Austral Entomology 59 (1): 3–15. https://doi.org/
https://doi.org/10.1111/aen.12433.
Ferretti, Nelson, Alda González, and Fernando Pérez–Miles. 2014.
“Identification of Priority Areas for Conservation in Argentina: Quantitative Biogeography Insights from Mygalomorph Spiders (Araneae: Mygalomorphae).” Journal Article.
Journal of Insect Conservation 18 (6): 1087–96.
https://doi.org/10.1007/s10841-014-9718-5.
Griffiths, Hannah M., Louise A. Ashton, Catherine L. Parr, and Paul Eggleton. 2021.
“The Impact of Invertebrate Decomposers on Plants and Soil.” New Phytologist 231 (6): 2142–49. https://doi.org/
https://doi.org/10.1111/nph.17553.
Hallmann, Caspar A., Martin Sorg, Eelke Jongejans, Henk Siepel, Nick Hofland, Heinz Schwan, Werner Stenmans, et al. 2017.
“More Than 75 Percent Decline over 27 Years in Total Flying Insect Biomass in Protected Areas.” Journal Article.
PLOS ONE 12 (10): e0185809.
https://doi.org/10.1371/journal.pone.0185809.
Harvey, Mark S., Michael G. Rix, Volker W. Framenau, Zoë R. Hamilton, Michael S. Johnson, Roy J. Teale, Garth Humphreys, and William F. Humphreys. 2011.
“Protecting the Innocent: Studying Short-Range Endemic Taxa Enhances Conservation Outcomes.” Journal Article.
Invertebrate Systematics 25 (1): 1–10.
https://doi.org/10.1071/IS11011.
Holloway, Joanne C., Michael J. Furlong, and Philip I. Bowden. 2008.
“Management of Beneficial Invertebrates and Their Potential Role in Integrated Pest Management for Australian Grain Systems.” Journal Article.
Australian Journal of Experimental Agriculture 48 (12): 1531–42.
https://doi.org/10.1071/EA07424.
Lavelle, P., T. Decaëns, M. Aubert, S. Barot, M. Blouin, F. Bureau, P. Margerie, P. Mora, and J.-P. Rossi. 2006.
“Soil Invertebrates and Ecosystem Services.” European Journal of Soil Biology 42: S3–15. https://doi.org/
https://doi.org/10.1016/j.ejsobi.2006.10.002.
Macadam, Craig R., and Jenni A. Stockan. 2015.
“More Than Just Fish Food: Ecosystem Services Provided by Freshwater Insects.” Ecological Entomology 40 (S1): 113–23. https://doi.org/
https://doi.org/10.1111/een.12245.
Marsh, Jessica R., Payal Bal, Hannah Fraser, Kate Umbers, Tanya Latty, Aaron Greenville, Libby Rumpff, and John C. Z. Woinarski. 2022.
“Accounting for the Neglected: Invertebrate Species and the 2019–2020 Australian Megafires.” Journal Article.
Global Ecology and Biogeography 31 (10): 2120–30. https://doi.org/
https://doi.org/10.1111/geb.13550.
Murphy, H. T., and S. van Leeuwen. 2021.
“Biodiversity: Flora and Fauna.” Report. Australian Government Department of Agriculture, Water; the Environment.
https://doi.org/10.26194/ren9-3639.
Myers, Norman. 1988.
“Threatened Biotas: "Hot Spots" in Tropical Forests.” Journal Article.
Environmentalist 8 (3): 187–208.
https://doi.org/10.1007/BF02240252.
Myers, Norman, Russell A. Mittermeier, Cristina G. Mittermeier, Gustavo A. B. da Fonseca, and Jennifer Kent. 2000.
“Biodiversity Hotspots for Conservation Priorities.” Journal Article.
Nature 403 (6772): 853–58.
https://doi.org/10.1038/35002501.
Porto, Rafaella Guimarães, Oswaldo Cruz-Neto, Marcelo Tabarelli, Blandina Felipe Viana, Carlos A. Peres, and Ariadna Valentina Lopes. 2021.
“Pollinator-Dependent Crops in Brazil Yield Nearly Half of Nutrients for Humans and Livestock Feed.” Global Food Security 31: 100587. https://doi.org/
https://doi.org/10.1016/j.gfs.2021.100587.
Reddin, Carl J., Martin Aberhan, Nussaïbah B. Raja, and Ádám T. Kocsis. 2022.
“Global Warming Generates Predictable Extinctions of Warm- and Cold-Water Marine Benthic Invertebrates via Thermal Habitat Loss.” Journal Article.
Global Change Biology 28 (19): 5793–5807. https://doi.org/
https://doi.org/10.1111/gcb.16333.
Reid, Walter V. 1998.
“Biodiversity Hotspots.” Journal Article.
Trends in Ecology & Evolution 13 (7): 275–80.
https://doi.org/10.1016/S0169-5347(98)01363-9.
Rix, Michael G., Joel A. Huey, Barbara Y. Main, Julianne M. Waldock, Sophie E. Harrison, Sarah Comer, Andrew D. Austin, and Mark S. Harvey. 2017.
“Where Have All the Spiders Gone? The Decline of a Poorly Known Invertebrate Fauna in the Agricultural and Arid Zones of Southern Australia.” Journal Article.
Austral Entomology 56 (1): 14–22. https://doi.org/
https://doi.org/10.1111/aen.12258.
Sands, Don P. A. 2018.
“Important Issues Facing Insect Conservation in Australia: Now and into the Future.” Journal Article.
Austral Entomology 57 (2): 150–72. https://doi.org/
https://doi.org/10.1111/aen.12342.
Stephenson, Birgitta, Bruno David, Joanna Fresløv, Lee J. Arnold, Jean-Jacques Delannoy, Fiona Petchey, Chris Urwin, et al. 2020.
“2000 Year-Old Bogong Moth (Agrotis Infusa) Aboriginal Food Remains, Australia.” Journal Article.
Scientific Reports 10 (1): 22151.
https://doi.org/10.1038/s41598-020-79307-w.
Taylor, Gary S., Michael F. Braby, Melinda L. Moir, Mark S. Harvey, Don P. A. Sands, Tim R. New, Roger L. Kitching, et al. 2018.
“Strategic National Approach for Improving the Conservation Management of Insects and Allied Invertebrates in Australia.” Journal Article.
Austral Entomology 57 (2): 124–49. https://doi.org/
https://doi.org/10.1111/aen.12343.
Townsend Peterson, A., and David M. Watson. 1998.
“Problems with Areal Definitions of Endemism: The Effects of Spatial Scaling.” Diversity and Distributions 4 (4): 189–94. https://doi.org/
https://doi.org/10.1046/j.1472-4642.1998.00021.x.
Ulrich, Josephine, Solveig Franziska Bucher, Nico Eisenhauer, Anja Schmidt, Manfred Türke, Alban Gebler, Kathryn Barry, Markus Lange, and Christine Römermann. 2020.
“Invertebrate Decline Leads to Shifts in Plant Species Abundance and Phenology.” Journal Article.
Frontiers in Plant Science 11.
https://doi.org/10.3389/fpls.2020.542125.
Wagner, David L., Eliza M. Grames, Matthew L. Forister, May R. Berenbaum, and David Stopak. 2021.
“Insect Decline in the Anthropocene: Death by a Thousand Cuts.” Journal Article.
Proceedings of the National Academy of Sciences 118 (2): e2023989118.
https://doi.org/10.1073/pnas.2023989118.