title: Resource subsidies between stream and terrestrial ecosystems under global change.
abstract: Streams and adjacent terrestrial ecosystems are characterized by permeable boundaries that are crossed by resource subsidies. Although the importance of these subsidies for riverine ecosystems is increasingly recognized, little is known about how they may be influenced by global environmental change. Drawing from available evidence, in this review we propose a conceptual framework to evaluate the effects of global change on the quality and spatiotemporal dynamics of stream-terrestrial subsidies. We illustrate how changes to hydrological and temperature regimes, atmospheric CO2 concentration, land use and the distribution of nonindigenous species can influence subsidy fluxes by affecting the biology and ecology of donor and recipient systems and the physical characteristics of stream-riparian boundaries. Climate-driven changes in the physiology and phenology of organisms with complex life cycles will influence their development time, body size and emergence patterns, with consequences for adjacent terrestrial consumers. Also, novel species interactions can modify subsidy dynamics via complex bottom-up and top-down effects. Given the seasonality and pulsed nature of subsidies, alterations of the temporal and spatial synchrony of resource availability to consumers across ecosystems are likely to result in ecological mismatches that can scale up from individual responses, to communities, to ecosystems. Similarly, altered hydrology, temperature, CO2 concentration and land use will modify the recruitment and quality of riparian vegetation, the timing of leaf abscission and the establishment of invasive riparian species. Along with morphological changes to stream-terrestrial boundaries, these will alter the use and fluxes of allochthonous subsidies associated with stream ecosystems. Future research should aim to understand how subsidy dynamics will be affected by key drivers of global change, including agricultural intensification, increasing water use and biotic homogenization. Our conceptual framework based on the match-mismatch between donor and recipient organisms may facilitate understanding of the multiple effects of global change and aid in the development of future research questions.
authors.affiliation: Synthesis Centre (sDiv) of the German Centre for Integrative Biodiversity Research (iDiv), Halle-Jena-Leipzig, Deutscher Platz 5e, Leipzig, Germany.|Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Müggelseedamm 310, 12587, Berlin, Germany.
authors.forename: Stefano
authors.initials: S
authors.lastname: Larsen
authors.affiliation: US Geological Survey, Southwest Biological Science Center, Grand Canyon Monitoring and Research Center, 2255 N. Gemini Dr., Flagstaff, AZ, 86001, USA.
authors.forename: Jeffrey D
authors.initials: JD
authors.lastname: Muehlbauer
authors.affiliation: Biogeodynamics and Biodiversity Group, Centre for Advanced Studies of Blanes (CEAB-CSIC), Carrer Accés Cala Sant Francesc, 14, 17300 Blanes, Girona, Spain.
authors.forename: Eugenia
authors.initials: E
authors.lastname: Marti
mesh_terms: D000383:Agriculture; D002245:Carbon Dioxide / Q000737:chemistry; D057231:Climate Change; D004463:Ecology; D017753:Ecosystem; D062070:Hydrology; D045483:Rivers; D012621:Seasons; D013696:Temperature
chemical_list: D002245:Carbon Dioxide
keywords: allochthonous detritus; ecosystem boundaries; riparian zone; temperature and hydrological regimes; trophic mismatches