Freshwater ecosystems of the southern region of the russian far east are undergoing extreme environmental change

Abstract

-The freshwater ecosystems of the Southern Region Of the Russian Far East (SRORFE) are subject to the influence of environmental extremes (especially heavy floods and droughts). Within forested areas, extreme floods do not destroy the ecosystems of rivers and floodplain lakes; in contrast, periodic medium and small floods alternating with low-flow periods are beneficial to these ecosystems. In the 21st century, the natural flood cycles will change, likely increasing the peaks of floods but decreasing the probability of rain during the dry season. Extreme floods can lead to the rapid depletion of river phytoplankton and zoobenthos and can cause long-term water hyper-eutrophication. Droughts will increase the probability of forest fires. The loss of forest cover due to logging and fires will intensify the unsteadiness of hydrological regimes of water bodies. In the SRORFE global environmental change, accompanied by increasing anthropogenic pressures and a lack of protective measures will cause a significant loss of biodiversity among freshwater biota. Meanwhile, forest preservation will ease the negative effects on the biodiversity and productivity of freshwater ecosystems in the SRORFE.Key-words: freshwater ecosystems / global warming environmental extremes / eutrophication / forest fires Résumé -Les écosystèmes d'eau douce de la région sud de l'Extrême-Orient russe subissent des changements environnementaux extrêmes. Les écosystèmes d'eau douce de la région du sud de l'Extrême-Orient russe (SRORFE) sont soumis à l'influence des conditions environnementales extrêmes (en particulier de fortes inondations et des séche-resses). Dans les zones boisées, les inondations ne détruisent pas les écosystèmes des rivières et des lacs des plaines inondables ; au contraire, de petites à moyennes inondations périodiques alternant avec des périodes de faible débit sont bénéfiques pour ces écosystèmes. Au 21 e siècle, les cycles naturels d'inondation vont changer, avec probablement augmentation des pics d'inondations, mais diminution de la probabilité de pluie pendant la saison sèche. Les crues extrêmes peuvent conduire à l'épuisement rapide du phytoplancton et du zoobenthos de la rivière et peuvent causer à long terme l'hyper-eutrophisation de l'eau. Les sécheresses augmenteront la probabilité d'incendies de forêt. La perte de la couverture forestière en raison de l'exploitation forestière et des incendies intensifiera le déséquilibre des régimes hydrologiques des masses d'eau. Dans le SRORFE, les changements environnementaux mondiaux, accompagnés d'une augmentation des pressions anthropiques et de l'absence de mesures de protection entraînent une perte importante de la biodiversité dans les communautés d'eau douce. En même temps, la préservation des forêts va atténuer les effets négatifs sur la biodiversité et la productivité des écosystèmes d'eau douce dans le SRORFE.Mots-clés : écosystèmes d'eau douce / réchauffement climatique / extrêmes environnementaux / eutrophisation / incendies de forêt

Caddisflies Stenopsyche marmorata (Trichoptera: Hydropsychidae) exploit river mussels as anchors for their nets

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Status, trends, and future dynamics of freshwater ecosystems in Europe and Central Asia

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