Assessing distribution shifts and ecophysiological characteristics of the only Antarctic winged midge under climate change scenarios

Abstract

parts of Antarctica were amongst the most rapidly changing regions of the planet during the second half of the Twentieth Century. Even so, today, most of Antarctica remains in the grip of continental ice sheets, with only about 0.2% of its overall area being ice-free. The continent's terrestrial fauna consists only of invertebrates, with just two native species of insects, the chironomid midges Parochlus steinenii and Belgica antarctica. We integrate ecophysiological information with the development of new highresolution climatic layers for Antarctica, to better understand how the distribution of P. steinenii may respond to change over the next century under different IPCC climate change scenarios. We conclude that the species has the potential to expand its distribution to include parts of the west and east coasts of the Antarctic Peninsula and even coastal ice-free areas in parts of continental Antarctica. We propose P. steinenii as an effective native sentinel and indicator species of climate change in the Antarctic. Antarctica and the sub-Antarctic islands are some of the last wilderness areas remaining on the planet. These remote areas remain, to a great extent, free from direct anthropogenic impacts such as overpopulation and overexploitation of native ecosystems 1 , although they are not immune to wider global anthropogenic processes such as climate change and long-range pollution 2,3. The high latitude regions of the Antarctic Peninsula, Scotia Arc, and the Magellanic Sub-Antarctic have been amongst the most rapidly warming areas in the world in the second half of the Twentieth Century, showing significant glacier retreat and reduction of snow and ice cover in terrestrial and freshwater ecosystems 3. While these strong regional warming trends have currently paused, they are predicted to resume through the remainder of the Twenty-first Century 4. These regions are highly sensitive to environmental change and thus are considered natural laboratories in which to study its effects, at all scales, on their ecosystems and biota 3,5. Today, Antarctica remains in the grip of continental ice sheets, with only about 0.2% of its overall area being ice-free 6 , this proportion is somewhat higher in the Antarctic Peninsula region (~3%; British Antarctic Survey unpublished data, Lee et al.. 2017). Terrestrial and freshwater ecosystems are generally small and isolated, populated by small invertebrates, lower plants, and microbes 7. The terrestrial fauna consists only of invertebrates, with just two native species of insects, both chironomid midges (the winged Parochlus steinenii Gerke and the brachypterous Belgica antarctica Jacobs), and two established invasive species with currently restricted ranges, Eretmoptera murphyi (Diptera: Chironomidae) and Trichocera maculipennis (Diptera: Trichoceridae) 8. Climatic gradients have changed over geological time at different spatio-temporal scales in these high latitude southern regions, shaping the composition and distribution of modern landscapes and their biota 3,9. The Eocen...

Macroinvertebrados dulceacuícolas del Parque Nacional Yendegala, Chile: Resolviendo brechas de conocimiento sobre la biodiversidad de la Reserva de la Biosfera Cabo de Hornos

“…La temperatura del agua y su variación en distintas escalas espaciales, es uno de los factores clave que influye directamente la distribución, ciclos de vida y fisiología de los macroinvertebrados dulceacuícolas (Vannote et al 1980, Contador et al 2016, 2020, Rendoll-Cárcamo et al 2020b. No obstante, este no es el único parámetro, que puede influenciar la composición estructural de una comunidad bentónica.…”

“…Lugares remotos y bien conservados del hemisferio sur, especialmente zonas de latitudes altas, representan un gran vacío de información. Además, estas regiones pueden ofrecer oportunidades para superar estas brechas y disminuir la incertidumbre de nuestras evaluaciones ambientales y predicciones, al mismo tiempo que permiten conservar la entomofauna (Contador et al 2020). En este contexto, el extremo austral de la ecorregión subantártica de Magallanes con su heterogénea orografía, fiordos, canales y cuencas hidrográficas, donde se localiza la RBCH, ofrece una oportunidad ideal para abordar estas brechas (Rendoll-Cárcamo et al 2020a).…”

Records of Parochlus steinenii in the Maritime Antarctic and sub-Antarctic regions

“…On the maritime Antarctic South Shetland Islands, ice-free areas on Deception, Livingston, Greenwich, Robert, Nelson, King George Islands, and the north-west coast of Antarctic Peninsula (Trinity Peninsula and Litchfield Island). These areas are characterized by a geomorphology which includes periglacial landforms, with numerous temporary shallow meltwater ponds and permanent lakes (typically smaller than 100 m²), which are ice-covered for 9–10 months of the year ( Contador et al 2020 ); 2. In South Georgia, which is the largest island on the Scotia Arc, with much of the barren, mountainous and highly glacial territory ( Regional ecosystem profile – Polar and Sub-polar Region 2017 ), we surveyed accessible lakes near the British Antarctic Survey research station; 3.…”

“… P. steinenii is recorded from freshwater ecosystems through the ice-free areas of the South Shetland Islands in the Maritime Antarctic, on sub-Antarctic South Georgia, and in Navarino and Horn islands in the CHBR . Knowing these presences is of great importance since P. steinenii has been proposed as an effective native sentinel species and indicator of climate change in Antarctica ( Contador et al 2020 ).…”

Antarctic: Climate Change, Fisheries, and Governance

“…For example, the presence of balanomorph barnacles and live individuals of the cosmopolitan pelagic barnacle, Conchoderma auritum, demonstrated the potential for non-native species to be transported to Antarctica this way (Hughes and Ashton 2017). Increasingly, modeling approaches are being used to predict potentially wide ranging future changes in distribution of both native and non-native terrestrial species in Antarctica (Bartlett et al 2020;Contador et al 2020;Hughes et al 2019;Pertierra et al 2017Pertierra et al , 2020.…”