KNO10: Arctic terrestrial invertebrate diversity

Date: Wednesday October 10, 2018

Location: Erottaja, ELY

Time: 10:30-12:00

This session brings together world-wide experts on Arctic terrestrial arthropod diversity to synthesize current knowledge and discuss the recommendations of the Circumpolar Biodiversity Monitoring Plan for terrestrial arthropods in light of recent advances in the field. The speakers are key representatives of the recently established UArctic thematic network – NeAT, Network for Arthropods of the Tundra formed at the first Arctic Biodiversity Congress in Trondheim 2014. The session will show case how NeAT has become an important expert network for digitizing and sharing of data and knowledge as well as for coordination of Circumarctic invertebrate biodiversity research, monitoring and management

Chairs: Toke T. Høye, Aarhus University

Format: Series of presentations followed by discussion

  • Controls on Arctic mosquito (Aedes nigripes) populations in western Greenland: Melissa H. Desiervo, Dartmouth College pdf
  • Global patterns in the species richness, phylogenetic diversity and ecological functioning of the flower-visitor communities of an arcto-alpine plant (Dryas): Tomas Roslin, Swedish Agricultural University pdf
  • Image-based monitoring of Arctic arthropods: Toke Høye, Aarhus University pdf
  • Warming alters the indirect effects of predators on ecosystem functioning in the Arctic: Amanda Koltz, Washington University, St. Louis 
  • Mapping constraints of climate and land type on insect compositions: Douglas Chesters, Institute of Zoology, Chinese Academy of Sciences, Beijing pdf

 


Abstracts:

 

Controls on Arctic mosquito (Aedes nigripes) populations in western Greenland

Melissa H. Desiervo, Dartmouth College

Mosquitoes (Diptera: Culicidae) are globally important arthropods with aquatic and terrestrial life stages. In Arctic ecosystems, they are abundant during the summer, and can be pests to humans and other mammals including caribou (Rangifer tarandus). In the spring, mosquito eggs hatch after ice melt, and the immatures develop in freshwater ponds where they are sensitive to thermal and hydrologic conditions. During larval development, populations are also influenced by predation from diving beetles. After emergence, female mosquitoes mate and search for a blood meal from a vertebrate host, representing another biotic control on mosquito abundance. We investigate drivers of mosquito population dynamics in Kangerlussuaq, Greenland, in a system with a sole species of mosquito (Aedes nigripes), few resource competitors, and few vertebrate hosts. To estimate immature density-dependent mortality and levels of resource competition, we use data from larval count surveys from four years and data from two experimental enclosure manipulation. We also investigate spatial dynamics of adult abundance using carbon dioxide trap and sweep net data from three years, testing the hypotheses that mosquito abundance and fecundity increases with suitable larval habitat and/or higher abundance of potential blood meals. Overall, our research indicates key drivers of mosquito population dynamics in both aquatic and terrestrial habitats that may fluctuate in importance depending on annual conditions and which range from strongly density-dependent to density-independent.

  

Global patterns in the species richness, phylogenetic diversity and ecological functioning of the flower-visitor communities of an arcto-alpine plant (Dryas)

Mikko Tiusanen1,*, Tea Huotari1,*, Paul D.N. Hebert2, Tommi Andersson3, Ashley Asmus4,5, Jennifer Gale6 , Bess Hardwick1, David Hik7, Christian Körner8, Richard B. Lanctot9, Maarten J.J.E. Loonen10 , Rauni Partanen11, Karissa Reischke12, Sarah T. Saalfeld9, Fanny Senez-Gagnon13, Ján Šulavík14,15, Ilkka Syvänperä16 , Christine Urbanowicz17, Sian Williams18, Paul Woodard19, Yulia Zaika20, Tomas Roslin1,21
1 Department of Agricultural Sciences, University of Helsinki, Finland
2 Centre for Biodiversity Genomics, Biodiversity Institute of Ontario, University of Guelph, Guelph, Ontario, Canada
3 Kevo Subarctic Research Station, Biodiversity Unit, University of Turku, Turku, Finland
4 Department of Ecology, Evolution and Behavior, University of Minnesota, Minnesota, USA
5 Department of Biology, University of Texas at Arlington, Arlington, Texas, USA
6 Institute of Environmental Science, Carleton University, Ottawa, Canada
7 Department of Biological Sciences, University of Alberta, Alberta, Canada
8 Institute of Botany, University of Basel, Basel, Germany
9 U.S. Fish and Wildlife Service, Anchorage, Alaska, USA
10 University of Groningen, Arctic Centre, The Netherlands, Groningen, The Netherlands
11 Kilpisjärvi Biological Station, University of Helsinki, Kilpisjärvi, Finland
12 Conservation Ontario, Newmarket, Ontario, Canada
13 Département des sciences du bois et de la forêt, Université Laval, Ville de Québec, Canada
14 Department of Environmental Sciences, Faculty of Engineering and Science, Western Norway University of Applied Sciences, Sogndal, Norway
15 Natural History Museum, University of Oslo, Oslo, Norway 16 Subarctic Research Station, Biodiversity Unit, University of Turku, Turku, Finland
17 Department of Biology, Dartmouth College, Hanover, New Hampshire, USA
18 Kluane Lake Research Station, Yukon, Canada 
19 Canadian Wildlife Service, Environment and Climate Change Canada, Yellowknife, Canada
20 Khibiny Academic Research Station, Department of Geography, Lomonosov Moscow State University, Russia
21 Department of Ecology, Swedish University of Agricultural Sciences, Uppsala, Sweden

 Pollination is an ecosystem function of global importance. Yet, who visits the flower of specific plants, how the composition of visitors varies in space and time, and how such variation translates into pollination services is typically hard to establish. To clarify regional variation in the visitor community of a wide-spread flower resource, we compare the structure of the arthropod community visiting mountain avens, Dryas, throughout the Arctic and alpine areas. At each of 15 sites, we sampled Dryas visitors with 100 sticky flower mimics, and identified specimens to Barcode Index Numbers (BIN) using a partial sequence of the mitochondrial COI-gene. As a measure of ecosystem functioning, we quantified variation in the seed set success of Dryas. To test for an association between phylogenetic and functional diversity, we characterized the structure of local visitor communities by both taxonomic and phylogenetic descriptors. In total, we detected 1288 different BINs, dominated by Diptera and Hymenoptera. Local BIN richness of visitors appeared to be driven by temperature and precipitation. Phylogeographic structure seemed reflective of geological history, and mirrored trans-Arctic patterns detected in plants. Seed set success varied widely among sites, with little variation attributable to pollinator species richness. This pattern suggests idiosyncratic associations, with function dominated by few and potentially different taxa at each site. Taken together, this information illustrates the role of post-glacial history in the assembly of flower-visitor communities at high Arctic, and offers insights for understanding how diversity translates into ecosystem functioning.

 

Image-based monitoring of Arctic arthropods

Toke Høye, Aarhus University; Alexandros Iosifids, Aarhus University; Oskar L.P. Hansen, Aarhus University; Kristian Meissner, Finnish Environment Institute

Understanding how biological communities respond to environmental changes is a key challenge in ecology and ecosystem management. For insects and their relatives - a key group of organisms in terrestrial ecosystems - we have very limited understanding of what drives variation in their abundance under natural conditions. Inefficient sampling procedures are a major factor in this limitation. Pitfall trapping, first used in 1896, is still the standard survey method for surface-active insects. Despite its widespread use, there are several recognized problems with pitfall trapping as a survey method. First, active animals are more likely to be trapped than sedentary animals. Thus, under warmer temperatures, capture rates of insects could increase due to either increased activity or increased abundance, or a combination of both. Second, pitfall trapping may deplete local insect populations over time and bias estimates of population trends. Third, sorting and identifying species from pitfall trap samples is very labour intensive. Given recent advances in Computer Vision the open questions are, is it possible to replace the antiquated standard manual approach to the sorting and identification by an automatic image-based technology, and can this be implemented to assess species identity and abundance under field conditions? We present evidence from recent lab and field efforts to validate image based methods for Arctic arthropod detection and identification using image data.

Predators can disproportionately impact the structure and function of ecosystems relative to their biomass. These effects may be exacerbated under warming in ecosystems like the Arctic, where the number and diversity of predators are low and small shifts in community interactions can alter carbon cycle feedbacks. Here we show that wolf spiders, one of the most abundant tundra predators, have different indirect effects on rates of belowground litter decomposition under ambient vs. warmer temperatures. Specifically, while high densities of wolf spiders result in faster litter decomposition under ambient temperatures, they result instead in slower decomposition under warming. The changes in decomposition were associated with trends toward fewer fungivorous Collembola under ambient temperatures and more Collembola under warming, suggesting that Collembola mediate the indirect effects of wolf spiders on decomposition. Our results indicate that climate change-induced effects on predators can cascade through other trophic levels, alter critical ecosystem functions, and potentially lead to climate feedbacks with important global implications.

 

Warming alters the indirect effects of predators on ecosystem functioning in the Arctic

Amanda M. Koltz,1* Aimée T. Classen2,3 and Justin P. Wright4
1. Department of Biology, Washington University in St. Louis, St. Louis, MO 63130
2. The Rubenstein School of Environment & Natural Resources, University of Vermont, Burlington, VT, 05405, USA 
3. The Gund Institute for Environment, University of Vermont, Burlington, VT, 05405, USA  4. Department of Biology, Duke University, Durham, NC 27708

Predators can disproportionately impact the structure and function of ecosystems relative to their biomass. These effects may be exacerbated under warming in ecosystems like the Arctic, where the number and diversity of predators are low and small shifts in community interactions can alter carbon cycle feedbacks. Here we show that wolf spiders, one of the most abundant tundra predators, have different indirect effects on rates of belowground litter decomposition under ambient vs. warmer temperatures. Specifically, while high densities of wolf spiders result in faster litter decomposition under ambient temperatures, they result instead in slower decomposition under warming. The changes in decomposition were associated with trends toward fewer fungivorous Collembola under ambient temperatures and more Collembola under warming, suggesting that Collembola mediate the indirect effects of wolf spiders on decomposition. Our results indicate that climate change-induced effects on predators can cascade through other trophic levels, alter critical ecosystem functions, and potentially lead to climate feedbacks with important global implications.

 

Mapping constraints of climate and land type on insect compositions

Douglas Chesters1, Philip Beckschäfer2, Sarah J. Adamowicz3, Michael C. Orr1, Chao-Dong Zhu1, Kwok-Pan Chun4.
1 Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.
2 Chair of Forest Inventory and Remote Sensing, Faculty of Forest Sciences and Forest Ecology, Georg-August-Universität Göttingen, Göttingen, Germany.
3 Biodiversity Institute of Ontario & Department of Integrative Biology, University of Guelph, Ontario, Canada.
4 Department of Geography, Hong Kong Baptist University, Hong Kong, China.

The arctic boasts a uniquely comprehensive dataset on insect genetics (DNA barcodes). Integrated with distribution, land cover and climate data, these provide unique opportunities to further understanding of constraints on insect distributions. We constructed a species level phylogeny of insects, integrating geographic data from GBIF, conducted climate classifications, inferred land type parameters from remote sensing databases. This allowed us to map past and present abiotic constraints for various insect lineages. There was compositional similarity in communities for different regions with similar seasonal features, while dissimilarity was similarly explained by alternative classifications of climate (Koppen-Geiger) and habitat (ecotypes), and vegetation indexes. Diversity was greater in higher temperatures and lower latitudes, although this was less pronounced in flies (e.g. chironomids and muscids). Exploitation of informatics procedures and the rapidly expanding databases now permits broad scale testing of hypotheses on climate-adaptation. The study represents a preliminary foundation on which risk predictions can be made for insect diversity from climate change in the Arctic.

Like us on Facebook
Follow us on Twitter
Subscribe to our YouTube Channel
Join our LinkedIn Group
Check us out on Google+
Follow Us on Instagam
Follow Us on Flickr