Browsing by Author "Olsen, Jeanine L."
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- Biodiversity mediates top-down control in eelgrass ecosystems: a global comparative-experimental approachPublication . Duffy, J. Emmett; Reynolds, Pamela L.; Bostroem, Christoffer; Coyer, James A.; Cusson, Mathieu; Donadi, Serena; Douglass, James G.; Ekloef, Johan S.; Engelen, Aschwin H.; Eriksson, Britas Klemens; Fredriksen, Stein; Gamfeldt, Lars; Gustafsson, Camilla; Hoarau, Galice; Hori, Masakazu; Hovel, Kevin; Iken, Katrin; Lefcheck, Jonathan S.; Moksnes, Per-Olav; Nakaoka, Masahiro; O'Connor, Mary I.; Olsen, Jeanine L.; Richardson, J. Paul; Ruesink, Jennifer L.; Sotka, Erik E.; Thormar, Jonas; Whalen, Matthew A.; Stachowicz, John J.Nutrient pollution and reduced grazing each can stimulate algal blooms as shown by numerous experiments. But because experiments rarely incorporate natural variation in environmental factors and biodiversity, conditions determining the relative strength of bottom-up and top-down forcing remain unresolved. We factorially added nutrients and reduced grazing at 15 sites across the range of the marine foundation species eelgrass (Zostera marina) to quantify how top-down and bottom-up control interact with natural gradients in biodiversity and environmental forcing. Experiments confirmed modest top-down control of algae, whereas fertilisation had no general effect. Unexpectedly, grazer and algal biomass were better predicted by cross-site variation in grazer and eelgrass diversity than by global environmental gradients. Moreover, these large-scale patterns corresponded strikingly with prior small-scale experiments. Our results link global and local evidence that biodiversity and top-down control strongly influence functioning of threatened seagrass ecosystems, and suggest that biodiversity is comparably important to global change stressors.
- A Pleistocene legacy structures variation in modern seagrass ecosystemsPublication . Duffy, J. Emmett; Stachowicz, John J.; Reynolds, Pamela L.; Hovel, Kevin A.; Jahnke, Marlene; Sotka, Erik E.; Boström, Christoffer; Boyer, Katharyn E.; Cusson, Mathieu; Eklöf, Johan; Engelen, Aschwin; Eriksson, Britas Klemens; Fodrie, F. Joel; Griffin, John N.; Hereu, Clara M.; Hori, Masakazu; Hughes, A. Randall; Ivanov, Mikhail V.; Jorgensen, Pablo; Kruschel, Claudia; Lee, Kun-Seop; Lefcheck, Jonathan S.; Moksnes, Per-Olav; Nakaoka, Masahiro; O’Connor, Mary I.; O’Connor, Nessa E.; Orth, Robert J.; Peterson, Bradley J.; Reiss, Henning; Reiss, Katrin; Richardson, J. Paul; Rossi, Francesca; Ruesink, Jennifer L.; Schultz, Stewart T.; Thormar, Jonas; Tomas, Fiona; Unsworth, Richard; Voigt, Erin; Whalen, Matthew A.; Ziegler, Shelby L.; Olsen, Jeanine L.Distribution of Earth's biomes is structured by the match between climate and plant traits, which in turn shape associated communities and ecosystem processes and services. However, that climate-trait match can be disrupted by historical events, with lasting ecosystem impacts. As Earth's environment changes faster than at any time in human history, critical questions are whether and how organismal traits and ecosystems can adjust to altered conditions. We quantified the relative importance of current environmental forcing versus evolutionary history in shaping the growth form (stature and biomass) and associated community of eelgrass (Zostera marina), a widespread foundation plant of marine ecosystems along Northern Hemisphere coastlines, which experienced major shifts in distribution and genetic composition during the Pleistocene. We found that eelgrass stature and biomass retain a legacy of the Pleistocene colonization of the Atlantic from the ancestral Pacific range and of more recent within-basin bottlenecks and genetic differentiation. This evolutionary legacy in turn influences the biomass of associated algae and invertebrates that fuel coastal food webs, with effects comparable to or stronger than effects of current environmental forcing. Such historical lags in phenotypic acclimatization may constrain ecosystem adjustments to rapid anthropogenic climate change, thus altering predictions about the future functioning of ecosystems.
- The biogeography of community assembly: latitude and predation drive variation in community trait distribution in a guild of epifaunal crustaceansPublication . Gross, Collin P.; Duffy, J. Emmett; Hovel, Kevin A.; Kardish, Melissa R.; Reynolds, Pamela L.; Boström, Christoffer; Boyer, Katharyn E.; Cusson, Mathieu; Eklöf, Johan; Engelen, Aschwin; Eriksson, Britas Klemens; Fodrie, F. Joel; Griffin, John N.; Hereu, Clara M.; Hori, Masakazu; Hughes, A. Randall; Ivanov, Mikhail V.; Jorgensen, Pablo; Kruschel, Claudia; Lee, Kun-Seop; Lefcheck, Jonathan; McGlathery, Karen; Moksnes, Per-Olav; Nakaoka, Masahiro; O'Connor, Mary I.; O'Connor, Nessa E.; Olsen, Jeanine L.; Orth, Robert J.; Peterson, Bradley J.; Reiss, Henning; Rossi, Francesca; Ruesink, Jennifer; Sotka, Erik E.; Thormar, Jonas; Tomas, Fiona; Unsworth, Richard; Voigt, Erin P.; Whalen, Matthew A.; Ziegler, Shelby L.; Stachowicz, John J.While considerable evidence exists of biogeographic patterns in the intensity of species interactions, the influence of these patterns on variation in community structure is less clear. Studying how the distributions of traits in communities vary along global gradients can inform how variation in interactions and other factors contribute to the process of community assembly. Using a model selection approach on measures of trait dispersion in crustaceans associated with eelgrass (Zostera marina) spanning 30 degrees of latitude in two oceans, we found that dispersion strongly increased with increasing predation and decreasing latitude. Ocean and epiphyte load appeared as secondary predictors; Pacific communities were more overdispersed while Atlantic communities were more clustered, and increasing epiphytes were associated with increased clustering. By examining how species interactions and environmental filters influence community structure across biogeographic regions, we demonstrate how both latitudinal variation in species interactions and historical contingency shape these responses. Community trait distributions have implications for ecosystem stability and functioning, and integrating large-scale observations of environmental filters, species interactions and traits can help us predict how communities may respond to environmental change.
- The genome of the seagrass Zostera marina reveals angiosperm adaptation to the seaPublication . Olsen, Jeanine L.; Rouze, Pierre; Verhelst, Brain; Lin, Yao-Cheng; Bayer, Till; Collen, Jonas; Dattolo, Emanuela; De Paoli, Emanuele; Dittami, Simon; Maumus, Florian; Michel, Gurvan; Kersting, Anna; Lauritano, Chiara; Lohaus, Rolf; Topel, Mats; Tonon, Thierry; Vanneste, Kevin; Amirebrahimi, Mojgan; Brakel, Janina; Bostrom, Christoffer; Chovatia, Mansi; Grimwood, Jane; Jenkins, Jerry W.; Jueterbock, Alexander; Mraz, Amy; Stam, Wytze T.; Tice, Hope; Bornberg-Bauer, Erich; Green, Pamela J.; Pearson, Gareth; Procaccini, Gabriele; Duarte, Carlos M.; Schmutz, Jeremy; Reusch, Thorsten B. H.; Van de Peer, YvesSeagrasses colonized the sea(1) on at least three independent occasions to form the basis of one of the most productive and widespread coastal ecosystems on the planet(2). Here we report the genome of Zostera marina (L.), the first, to our knowledge, marine angiosperm to be fully sequenced. This reveals unique insights into the genomic losses and gains involved in achieving the structural and physiological adaptations required for its marine lifestyle, arguably the most severe habitat shift ever accomplished by flowering plants. Key angiosperm innovations that were lost include the entire repertoire of stomatal genes(3), genes involved in the synthesis of terpenoids and ethylene signalling, and genes for ultraviolet protection and phytochromes for far-red sensing. Seagrasses have also regained functions enabling them to adjust to full salinity. Their cell walls contain all of the polysaccharides typical of land plants, but also contain polyanionic, low-methylated pectins and sulfated galactans, a feature shared with the cell walls of all macroalgae(4) and that is important for ion homoeostasis, nutrient uptake and O-2/CO2 exchange through leaf epidermal cells. The Z. marina genome resource will markedly advance a wide range of functional ecological studies from adaptation of marine ecosystems under climate warming(5,6), to unravelling the mechanisms of osmoregulation under high salinities that may further inform our understanding of the evolution of salt tolerance in crop plants(7).