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Smaller future floods imply less habitat for riparian plants along a boreal river
Author(s) -
Jansson Roland,
Ström Lotta,
Nilsson Christer
Publication year - 2019
Publication title -
ecological applications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.864
H-Index - 213
eISSN - 1939-5582
pISSN - 1051-0761
DOI - 10.1002/eap.1977
Subject(s) - riparian zone , habitat , environmental science , boreal , climate change , flood myth , ecology , streamflow , vegetation (pathology) , riparian forest , hydrology (agriculture) , geography , physical geography , drainage basin , biology , geology , medicine , cartography , geotechnical engineering , archaeology , pathology
Abstract Climate‐change projections suggest large changes in riverine flow regime, which will likely alter riparian communities. In northern Europe, forecasts propose lower annual spring flood peaks and higher winter flows, resulting in narrower riparian zones. To estimate the impact of climate change on habitat extent of riparian plants, we developed a framework estimating the sensitivity and exposure of individual species to streamflow change, and surveyed five reaches along the free‐flowing Vindel River in northern Sweden. We modeled the hydrologic niche of riparian plant species based on the probability of occurrence along gradients of flood frequency and duration and used predicted future water‐level fluctuations (based on climate models and IPCC emission scenarios) to calculate changes in flow‐related habitat availability of individual species. Despite projected increases in runoff, we predict most species to decrease in riparian elevational extent by on average 12–29% until the end of the century, depending on scenario. Species growing in the upper, spring‐flood‐controlled part of the riparian zone will likely lose most habitat, with the largest reductions in species with narrow ranges of inundation duration tolerance (decreases of up to 54%). In contrast, the elevational extent of most amphibious species is predicted to increase, but conditions creating isoëtid vegetation will become rarer or disappear: isoëtid vegetation is presently found in areas where ice formed in the fall settles on the riverbank during the winter as water levels subside. Higher winter flows will make these conditions rare. We argue that our framework is useful to project the effects of hydrologic change caused by climate change as well as other stressors such as flow regulation also in other regions. With few rivers remaining unaffected by dams and other human stressors, these results call for monitoring to detect species declines. Management to alleviate species losses might include mitigation of habitat degradation from land‐use activities, more environmentally friendly flow schemes, and more intensive management options such as mowing riparian meadows no longer regularly maintained by recurrent floods.