Michielon 4Th River Conference 2017
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Conservation of the endangered shrub Myricaria germanica in regulated Alpine rivers of North-East Italy Overview Bruno Michielon & Tommaso Sitzia Myricaria germanica 15th International Alpine Workshop Tagliamento Ecohydrological processes 2017 4th River Conference Myricaria germanica in North-East Italy Region Negative impacts of human actions Positive impacts of human actions Overview Bruno Michielon & Tommaso Sitzia Kurt Stueber from Thomé 1905 How natural are Alpine mountain rivers? Evidence from the Italian Alps Francesco Comiti Overview The Piave River just upstream of Belluno during the late 19th century. Only scattered trees cover the hillslopes and the Bruno Michielon & Tommaso Sitzia 3 floodplain. A wood raft is floating down the course (painting by Alessandro Seffer, 1831–1905). Overview Bruno Michielon & Tommaso Sitzia 4 Fassa Valley and Avisio River after the flood of 1882. Photo: Dantone F. Overview Braided river, Sulden/Solda River, Prad am StilfserJoch/Prato Braided river, Upper Rangitata or Rakaia, Rakaia River, allo Stelvio, Prader Sand, South Tyrol. Bruno Michielon & TommasoCanterbury Sitzia Region, South Island, New Zealand. 5 Photo: Unterberger F., ca. 1890 Photo: Hargreaves K., ca. 2010 Overview Rhine River, a channelized European river, Germany. Tagliamento River, the only European braided river, Italy. Bruno Michielon & Tommaso Sitzia 6 Photo: Abeling J. 2011 Photo: www.udine20.it ca. 2000 Overview Ratschings/Racines, Ridnaun/Ridanna Valley, SouthBruno Michielon Tyrol. & TommasoRatschings/Racines, Sitzia Ridnaun/Ridanna Valley, South7 Tyrol. Photo: Athesiadruck Bozen, about 1970 Photo: Michielon B. 2016 Overview Trafoi, Stilfs/Stelvio, Trafoi Torrent, South Tyrol. Trafoi, Stilfs/Stelvio, Trafoi Torrent, South Tyrol. No presence of Myricaria germanica. Presence of Myricaria germanica. Bruno Michielon & Tommaso Sitzia 8 Photo: Photochromie ca. 1890 Photo: Michielon B. 2015 Natural braided river bar bar bar bar Overview Channelized river Bruno Michielon & Tommaso Sitzia 9 modified from Chesapeake Quarterly. Vol. 14, n. 1 germanica Myricaria Department of Life Science, University of Trieste, Photo: Moro A. Myricaria germanica (L.) Desv.Bruno Michielon & Tommaso Sitzia 10 Characteristic species of braided alpine rivers in Europe and Asia, today highly endangered in all European countries. Enrico Gelmi (Trento, 1855-1901) Specimens collected: Myricaria germanica (L.) Desv. • Piné [9833/3] - 18/8/1894 • Piné, Serraia [9833/4] - 11/8/1889 • Near Trento [9932/2]. germanica Myricaria Often in the bed of streams and inBruno sandy Michielonplaces & Tommaso. Sitzia germanica Myricaria Bruno Michielon & Tommaso Sitzia 12 Photo: Michielon B. 2009 germanica Myricaria Bruno Michielon & Tommaso Sitzia 13 Photo: Michielon B. 2009 germanica Myricaria Bruno Michielon & Tommaso Sitzia 14 Photo: Michielon B. 2009 Seed Germination: Seed production the critical process and dispersion Senescence and death Seedling germanica Myricaria germanica Stabilization: survival, cycle settlement Flowering, Fruiting and growth Myricaria Reproductive maturity Juvenile stage Development: growth of young plants Bruno Michielon & Tommaso Sitzia Modified from Lener 2011 germanica Myricaria Bruno Michielon & Tommaso Sitzia 16 Germination needs moist sand Photo: Gröger A. München germanica Myricaria Prad am Stilfserjoch/Prato allo Stelvio, Prader Sand Biotope, Sulden/Solda River, 890 m a.s.l., South Tyrol. Bruno Michielon & Tommaso Sitzia 17 Photo: Michielon B. 2012 Native Range germanica Myricaria Bruno Michielon & Tommaso Sitzia 18 Lener Felicia Pia 2011 (from Meusel et al. 1978) Habitat 3230 in SCI areas 10 x 10 km squares germanica Myricaria Bruno MichielonOfficial & Tommasodata, Sitzia but not updated. 19 Alien Range Myricaria germanica Myricaria Bruno Michielon & Tommaso Sitzia 20 germanica Myricaria BrunoBruno MichielonMichielon && TommasoTommaso SitziaSitzia 21 Tagliamento River and European rivers New Zealand Most important river factors and (except braided rivers or with features Tagliamento River) braided sections (over 300 rivers) Type of river system channelized L braided Hydro-morphological processes altered L almost natural River gravel dynamics low L great germanica Natural river flows altered L almost natural Active channel width narrow L wide Habitat characteristics degradated L disturbed Myricaria European native New Zealand alien Myricaria germanica range range Myricaria germanica population trend declining L increasing L Endangered Alien invasive Myricaria germanica status Bruno Michielon & TommasoVulnerable Sitzia L Naturalized L Myricaria germanica is important because is… • “una specie sentinella, per il suo valore quale indicatore ecologico” (Lasen 2006) • “an indicator of high biotic integrity” (Gostner et al. 2010) • “a charismatic riparian species” (Werth & Scheidegger 2011) • “an indicator species for alpine rivers with natural dynamics” (Lener 2011) germanica • “an indicator species of alpine rivers” (Halada et al. 2012) • “un indicatore di successo di interventi di riqualificazione morfologica” (Kofler et al. 2012) Myricaria • “an indicator plant of natural Alpine river systems (Maddock et al. 2013) • “a keystone / flagship species for riverine landscape diversity” (Kudrnovsky 2013) • “der Leitart” (Landmann 2013) • “a good indicator of a wide activeBruno Michielonchannel & Tommasoriver Sitzia ” (Sitzia et al. 2016) 23 germanica Ecosystem: German tamarisk-pioneer vegetation Year: 2016 EN Category: EN Region: Europe Myricaria Country: Various Ecosystem: German tamarisk-pioneer vegetation Year: 2016 Category: EN Region: Europe Bruno Michielon & Tommaso Sitzia 24 Country: Various German tamarisk - pioneer vegetation (GTPV) • GTPV is characterized by low to very low vegetation cover composed of herbs and shrubs, large fractions of bare gravel and sandy substrate, and high spatio-temporal heterogeneity between microsites regarding flooding regime, substrate grain size, and vegetation cover. • The dominating vascular plant species is the low shrub German tamarisk (Myricaria germanica). • GTPV colonizes periodically flooded gravel and sand banks, predominantly along braided rivers which germanica transport high sediment loads and show pronounced hydro-morphological dynamics. • Suitable sites are subject to periodically heavy flooding, which relocate the substrate and reset the succession to vegetation free bare gravel and sand banks. • Most of GTPV has been lost due to wide-spread alterations of hydro-morphological processes of Myricaria running waters in Europe. • From the mid-19th to the mid-20th centuries, losses were mainly driven by the effects of river channelization. In the last decades, the construction of hydro- electric power plants has emerged as a second main threatening factor. Both threats alter vital hydro-morphological processes, reduce river gravel dynamics and affect flood pulses, all being essential features for this ecosystem to develop and persist. Bruno Michielon & Tommaso Sitzia 25 • This ecosystem has been classified as Endangered. Estimated share of global distribution of GTPV in European countries, estimated decline in GTPV distribution per country during the last 50 years and since 1750. germanica Myricaria Bruno Michielon & Tommaso Sitzia 26 Myricaria germanica BrunoMichielon Tommaso& Sitzia The drivers of riparian plants Flow regime Propagule pressure • disturbance (flooding) • human land-cover • drought (low flows) • native land-cover • size and proximity of exotic / native plants propagule sources processes Climate • temperature • precipitation Human influence • road and track development Floodplain • size and proximity of human population • gravel / sediment size • time of human settlement Ecohydrological • substrate-moisture availability • level of human disturbance • isolation from active channels • flow regulation of rivers Bruno Michielon & Tommaso Sitzia 28 Modified from Brummer T. 2016 Gesamtlänge Fließgewässer: 9.680 km / Lunghezza totale dei corsi d’acqua: 9.680 km davon Gesamtlänge Fischgewässer: 2.040 km / di cui popolati da pesci: 2.040 km Ufer Gesamtlänge: 19.360 km, davon nicht verbaut: 8.620 km, Anzahl Querbauwerke (z. B. Sperren): 26.600 Lunghezza totale delle rive: 19.360 km, di cui prive di strutture artificiali: 8.620 km, numero di strutture trasversali: 26.600 Check dams about 26,600 Bank protections about 10,740 km processes Ecohydrological Today Myricaria germanica surviveBruno Michielonin 0,15%& Tommaso banks Sitzia of South Tyrol river courses 29 processes Ecohydrological 32 Hydroelectric power plants with nominal power greater than 3.000 kW 144 Hydroelectric power plants with nominal power between 220-3.000 kW 827 Hydroelectric power plants with nominal power below 220 kW Bruno Michielon & Tommaso Sitzia 30 Avisio River, Lago di Tesero, Fiemme Valley, Trentino Region processes 1973 Ecohydrological 2012 Bruno Michielon & Tommaso Sitzia 31 Adults 2009 Adults 2010 5150000 5150000 5140000 5140000 5130000 5130000 690000 695000 700000 705000 710000 690000 695000 700000 705000 710000 Adults 2009 Adults 2010 5150000 Adults 2009 5150000 Adults 2010 Adults 2009 Adults 2010 5150000 5150000 5150000 5150000 Adults 2011 Adults 2012 5150000 5150000 5140000 5140000 5140000 5140000 5140000 5140000 5140000 5140000 5130000 5130000 5130000 5130000 5130000 Long-term population dynamic5130000 in a regulated river 5130000 5130000 690000690000695000695000700000700000705000705000710000710000 690000690000695000695000700000700000705000705000710000710000 690000 695000 700000 705000 710000