EBM2: The CBMP Freshwater: Coordinated monitoring and assessment to improve knowledge on status and trends in circumpolar Arctic freshwaters

Date: Tuesday October 9, 2018

Location: Tieva, Lappia Hall

Time: 13:00-14:30

Arctic freshwater ecosystems are affected by natural and human-induced stressors resulting from climate change and industrial development. This session will examine changes in biodiversity of such freshwater ecosystems in relation to ongoing and predicted environmental change. The session will include recent findings on the state of Arctic freshwater biodiversity developed through the CBMP Freshwater, such as assessments on key circumpolar regions (e.g., North America, Greenland, Fenno-Scandia) and Focal Ecosystem Components (e.g., fish, benthos, algae). Presentations will also focus on recent advances in tools and approaches for assessing circumpolar freshwater biodiversity. The session will conclude with a panel presentation on relevance to the Arctic Biodiversity Assessment recommendations, as well as discussion of novel tools and approaches for Arctic freshwater biodiversity assessment and research gaps. The session will bring together international experts from multiple disciplines and emphasize the connectivity between science, monitoring and management necessary to implement CBMP and ABA frameworks across circumpolar freshwaters.

Chairs: Joseph Culp, Environment and Climate Change Canada; Willem Goedkoop, Swedish University of Agricultural Sciences

Format: Series of presentations followed by discussion

Presentations:

Arctic Freshwater Plankton Response to Environmental Stressors on a Circumpolar Scale: Kirsten Christoffersen, University of Copenhagen, University Centre in Svalbard
Circumpolar trends of diatoms: Maria Kahlert, Swedish University of Agricultural Sciences
Circumpolar analysis of lake macrophyte communities for setting the baseline for future assessment: Seppo Hellsten, Finnish Environment Institute
Biodiversity of benthic macroinvertebrates across the circumpolar region: evidence of latitudinal declines in richness in Arctic rivers and lakes: Jennifer Lento, University of New Brunswick
Drivers of freshwater fish biodiversity depend on location and isolation in the circumpolar Arctic: Sarah Laske, US Geological Survey

Abstracts:

Arctic Freshwater Plankton Response to Environmental Stressors on a Circumpolar Scale

Kirsten Christoffersen, University of Copenhagen, University Centre in Svalbard; Ann Kristin Schartau, Heather Mariash, Daniel Bogan, Olga Dubovskaya, Arni Einarsson, Elena Fefilova, Brian Hayden, Haraldur R. Ingvarsson, Elena Ivanova, Kimmo Kahilainen, Olga Kononova, Elena Kravchuk, Jennifer Lento, Anna Novichkova, Milla Rautio, Kathleen Ruhland, Rebecca Shaftel, John Smol, Tobias Vrede

Arctic freshwaters are facing a number of environmental pressures, including climate change, eutrophication caused by population expansion, and contamination from industry. Freshwater plankton assemblages are expected to reflect the impacts of these stressors through shifts in productivity and species composition. This paper examines spatial trends in phytoplankton and zooplankton biodiversity through the circumpolar region, and relates those trends to changes in environmental stressors. An analysis of times series data is used to evaluate persistence and temporal shifts in community structure. Patterns in biodiversity and environmental stressors are evaluated with respect to the impact hypotheses described in the CBMP-Freshwater Monitoring Plan to allow discussion of current and future responses to environmental pressures on Arctic plankton communities.

Circumpolar trends of diatoms

Maria Kahlert, Swedish University of Agricultural Sciences; Isabelle Lavoie, Kathleen M. Rühland, Francois Keck, Emilie Saulnier-Talbot, Daniel Bogan, Robert Brua, Stephane Campeau, Joseph Culp, Kirsten Christoffersen, Árni Einarsson, Jennifer Lento, Satu-Maaria Karjalainen, Susanne Schneider, Rebecca Shaftel, John P. Smol

Better data harmonization is required to improve environmental monitoring programs. Here, a large dataset of circum-Arctic contemporary and paleolimnological diatom assemblages was harmonized and used to establish current (point-in-time reference) and pre-industrial environmental conditions, and to explore spatio-temporal trends in diatom assemblages in a warming Arctic. Spatial trends from contemporary samples suggest that certain diatom assemblage clusters are specific to the high Arctic zone, and that these differ taxonomically between lakes and streams. Paleolimnological records show spatially and temporally heterogeneous and highly variable magnitudes of diatom compositional change across the study region. Areas where the least amount of change occurred include northernmost Québec, Baffin Island, and the Central Canadian Archipelago. Sites in Northeastern NWT showed moderate change, whereas the greatest changes were recorded in the northernmost sites (Ellesmere Island), the southernmost sites (southern Hudson Bay), and near the Beaufort Sea coast. Many lakes that register striking assemblage compositional shifts can clearly be linked to trajectories of recent Arctic warming. The results from this study will be key to establishing the foundation for future assessments of global and regional trends across the Arctic.

Circumpolar analysis of lake macrophyte communities for setting the baseline for future assessment

Seppo Hellsten, Finnish Environment Institute; Patricia Chambers, Environment and Climate Change Canada

Aquatic macrophyte richness is typically decreasing towards northern hemispheres with increasing altitude. Harsh climate is restricting distribution of helophytes on the littoral zone and number of submerged vascular plants is decreasing and replaced by mosses. In this study we collected extensive lake macrophyte data consisting of 440 lakes situated on sub-arctic zone and covering all northern countries except Russia. Main aim was to establish a baseline for current macrophyte species distribution and composition in different broad lake types. Species richness varied a lot with several lakes without any species or only with aquatic mosses. Share of aquatic mosses increased with increasing latitude whereas highest richness was reached at latitude of 68 degree, where a lot of low altitude lakes exist. Spatial analysis showed that communities were quite isolated between different continents whereas similar communities were found in the Fennoscandia. Most of the lakes were in pristine condition but there were some marks of nutrient enrichment indicated by presence of lemnids. This study confirmed the role of aquatic macrophytes as a part of lake biota also in northernmost area of globe. Study was a part of the circumpolar biodiversity monitoring program (CBMP) organised by secretariat of CAFF (Conservation of Arctic Flora and Fauna).

Biodiversity of benthic macroinvertebrates across the circumpolar region: evidence of latitudinal declines in richness in Arctic rivers and lakes

J. Lento; B. Levenstein; J. Culp; W. Goedkoop; J. Aroviita; M. Baturina; D. Bogan; J. Brittain; K. Chin; C. Docherty; A. Einarsson; N. Friberg; J. Heino; T. Hrafnsdóttir; D. Jacobsen; D. Lau; O. Loskutova; A. Milner; H. Mykrä; A. Novichkova; J. Ólafsson; A.K. Schartau; R. Shaftel

Across the Arctic, variation in warming rates, development, and biogeography may be expected to contribute to changes in biodiversity of freshwater organisms. Critical to detecting such changes is the quantification of existing biodiversity patterns across the Arctic region; however, assessments of benthic macroinvertebrate assemblage structure in Arctic freshwaters have been largely regional in scope. As part of the CBMP-Freshwater Arctic biodiversity assessment, we evaluated alpha and beta diversity across the circumpolar region using data collected from all Arctic countries. In both lakes and rivers, rarefied alpha diversity decreased with increasing latitude. This trend was most evident above 68°N, and reflected the loss of EPT taxa and increased dominance of Diptera. Species turnover contributed more to beta diversity than nestedness within the majority of ecoregions. Comparison of composition among ecoregions indicated that high Arctic islands exhibited a great deal of nestedness with lower latitude mainland stations, and were thus characterized by a subset of the taxa found at lower latitudes. These broad-scale diversity patterns can be used to make predictions about compositional changes that may be expected with continued climate change.

Drivers of freshwater fish biodiversity depend on location and isolation in the circumpolar Arctic

Sarah Laske, US Geological Survey; Svenning, Martin, Norwegian Institute for Nature Research (NINA); Amundsen, Per-Arne, UiT The Arctic University of Norway; Christoffersen, Kirsten, University of Copenhagen; Erkinaro, Jaakko, Natural Resources Institute Finland; Guðbergsson, Guðni, Marine and Freshwater Research Institute; Hayden, Brian, University of New Brunswick, Canadian Rivers Institute; Heino, Jani, Finnish Environment Institute, Natural Environment Centre, Biodiversity; Kahilainen, Kimmo, University of Helsinki; Lento, Jennifer, University of New Brunswick; Orell, Panu, Natural Resources Institute Finland; Östergren, Johan, Swedish University of Agricultural Sciences; Power, Michael, University of Waterloo, Waterloo; Rafikov, Ruslan Romakkaniemi, Atso, Natural Resources Institute Finland; Solbakken, Jan-Idar, Sámi University of Applied Sciences; Swanson, Heidi, University of Waterloo; Whitman, Matt, US Bureau of Land Management; Zimmerman, Christian, USGS Alaska Science Center

Fish are an important component of freshwater ecosystems but remain poorly studied and monitored throughout much of the Arctic. The biodiversity of these species maintains the structure, function, and integrity of these ecosystems; however, current anthropogenic forces (e.g., climate and land-use) are initiating rapid changes in freshwater systems that threaten biodiversity. To describe the complex spatial patterns of biodiversity across the circumpolar Arctic, we examined alpha and beta diversity using data gathered for the Arctic Freshwater Biodiversity Monitoring Plan. There are c. 125 species of freshwater fish that occur across the Arctic; we have data on 44% of species. Freshwater fish incidence data showed high turnover of species across geographic regions, with few fishes (< 10) occurring across regions. Detailed analysis of three regions indicated little difference in overall beta diversity. However, significant differences in diversity components resulted from variation in alpha diversity and species composition for island versus mainland fish communities. Describing patterns of diversity across large spatial scales is one of the first steps in accurately determining the status of freshwater fishes, what stressors play a role in biodiversity change, and how freshwater fish biodiversity should be monitored.