Abstract
Shrub encroachment is one of the main consequences of abandonment of montane grassland. Higher surface roughness of shrubs leads to stronger aerodynamic coupling. This should increase evapotranspiration (ET), but lower surface temperatures (due to higher ET and reduced aerodynamic resistance) could counter this effect. We explored this question by employing weighable lysimeters in adjacent grass- and shrubland understorey, and by measuring canopy transpiration in Alnus with sap flow sensors at 1675 m a.s.l. in the Swiss central Alps. For 11 bright days, ET rates of Alnus clearly exceeded those from grassland by on average 31 ± 14% or 1.2 ± 0.6 mm d−1 (mean ± sd). During days with a high vapour pressure deficit (VPD), differences in ET were largest, indicating that enhanced aerodynamic coupling had a greater influence than evaporative cooling. Cooler Alnus than grassland canopies were confirmed by infrared thermography. For the growing season (mid May to end of September), we estimate that this increase in ET results in a reduction in runoff by 78 to 81 mm (2010, 2011). Accounting for the falling height of water, this lower runoff reduces the hydro-electric potential of the upper Reuss catchment (227 km2) by 0.47 Mio Swiss Franc (CHF) per growing season (same amount in US Dollar (USD); Alnus cover analysed for the year 2004/05) and by 1.8 Mio CHF for a scenario where all grasslands below the natural treeline would be converted into shrubland. So, shrub encroachment clearly exerts hydrological drawbacks.
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Alaoui A, Willimann E, Jasper K, Felder G, Herger F, Magnusson J, Weingartner R (2014) Modelling the effects of land use and climate changes on hydrology in the Ursern valley, Switzerland. Hydrol Process 28:3602–3614. https://doi.org/10.1002/hyp.9895
Baker JM, van Bavel CHM (1987) Measurement of mass flow of water in the stems of herbaceous plants. Plant Cell Environ 10:777–782. https://doi.org/10.1111/1365-3040.ep11604765
Baur P, Müller P, Herzog F (2007) Alpweiden im Wandel. Agrarforschung 14:254–259
Bosch J, Hewlett J (1982) A review of catchment experiments to determine the effect of vegetation changes on water yield and evapotranspiration. J Hydrol 55:3–23. https://doi.org/10.1016/0022-1694(82)??90117-2
Brantley ST, Young DR (2010) Shrub expansion stimulates soil C and N storage along a coastal soil chronosequence. Glob Change Biol 16:2052–2061. https://doi.org/10.1111/j.1365-2486.2009.02129.x
Brown AE, Zhang L, McMahon TA, Western AW, Vertessy RA (2005) A review of paired catchment studies for determining changes in water yield resulting from alterations in vegetation. J Hydrol 310:28–61. https://doi.org/10.1016/j.jhydrol.2004.12.010
Bühlmann T, Hiltbrunner E, Körner C (2014) Alnus viridis expansion contributes to excess reactive nitrogen release, reduces biodiversity and constrains forest succession in the alps. Alp Bot 124:187–191. https://doi.org/10.1007/s00035-014-0134-y
Bühlmann T, Körner C, Hiltbrunner E (2016) Shrub expansion of Alnus viridis drives former montane grassland into nitrogen saturation. Ecosystems 19:968–985. https://doi.org/10.1007/s10021-016-9979-9
Bunza G (1978) Vergleichende Messungen von Abfluss und Bodenabtrag auf Almflächen des Stubnerkogels im Gasteiner Tal. In: Cernusca A (ed) Ökologische Analysen von Almflächen im Gasteiner Tal. Wagner, Innsbruck p 315–334
Caviezel C, Hunziker M, Schaffner M, Kuhn N (2014) Soil–vegetation interaction on slopes with bush encroachment in the central alps–adapting slope stability measurements to shifting process domains. Earth Surf Process Landf 39:509–521. https://doi.org/10.1002/esp.3513
Chapin FS, Sturm M, Serreze MC, McFadden JP, Key JR, Lloyd AH, McGuire AD, Rupp TS, Lynch AH, Schimel JP, Beringer J, Chapman WL, Epstein HE, Euskirchen ES, Hinzman LD, Jia G, Ping CL, Tape KD, CDC T, Welker JM (2005) Role of land-surface changes in Arctic summer warming. Science 310:657–660. https://doi.org/10.1126/science.1117368
Cernusca A, Seeber MC, Mayr R, Horvath A (1978) Bestandesstruktur, Mikroklima und Energiehaushalt von Almböden bei Badgastein. Ökologische Analysen von Almflächen im Gasteiner Tal. Veröff. Österr. MaB-Hochgebirgsprogr Hohe Tauern 2:47–66
De Bruin H, Stricker J (2000) Evaporation of grass under non-restricted soil moisture conditions. Hydrol Sci Journal 45:391–406 doi: https://doi.org/10.1080/0262660009492337
De Jong C, List FK, Ergenzinger PJ (2002) Experimental hydrological analyses in the Dischma based on daily and seasonal evaporation. Hydrol Res 33:1–14. http://hr.iwaponline.com/content/33/1/1
Dumas D (2011) The impact of forests on the evolution of water resources in the mid-altitude alps from the middle of the 19th century (Chartreuse massif, France). J Alpine Res| Revue de géographie alpine 99–3
Eidgenössische Elektrizitätskommission ElCom (2013) https://www.strompreis.elcom.admin.ch/Map/ShowSwissMap.aspx, Accessed December 2016
Dynamax Inc. (2005) User manual. available online at: http://dynamax.com/images/uploads/papers/Dynagage_Manual.pdf, Accessed May 2010
Eldridge DJ, Bowker MA, Maestre FT, Roger E, Reynolds JF, Whitford WG (2011) Impacts of shrub encroachment on ecosystem structure and functioning: towards a global synthesis. Ecol Lett 14:709–722. https://doi.org/10.1111/j.1461-0248.2011.01630.x
Eldridge DJ, Maestre FT, Maltez-Mouro S, Bowker MA (2012) A global database of shrub encroachment effects on ecosystem structure and functioning. Ecology 93:2499–2499. https://doi.org/10.1890/12-0749.1
Fairhead J, Leach M (1996) Misreading the African landscape: society and ecology in a forest-savanna mosaic. Cambridge University Press, Cambridge
Farley KA, Jobbagy EG, Jackson RB (2005) Effects of afforestation on water yield: a global synthesis with implications for policy. Globl Change Biol 11:1565–1576. https://doi.org/10.1111/j.1365-2486.2005.01011.x
Federal Office of Meteorology and Climatology (2015) www.meteoswiss.admin.ch accessed December 2015
Gebauer T, Horna V, Leuschner C (2012) Canopy transpiration of pure and mixed forest stands with variable abundance of European beech. J Hydrol 442:2–14. https://doi.org/10.1016/j.jhydrol.2012.03.009
Gehrig-Fasel J, Guisan A, Zimmermann NE (2007) Tree line shifts in the Swiss alps: climate change or land abandonment? J Veg Sci 18:571–582. https://doi.org/10.1111/j.1654-1103.2007.tb02571.x
Gellrich M, Baur P, Koch B, Zimmermann NE (2007) Agricultural land abandonment and natural forest re-growth in the Swiss mountains: a spatially explicit economic analysis. Agric Ecosys Environ 118:93–108. https://doi.org/10.1016/j.agee.2006.05.001
Grime VL, Sinclair FL (1999) Sources of error in stem heat balance sap flow measurements. Agricultural and Forest Meteorology 94 (2):103-121. https://doi.org/10.1016/S0168-1923(99)00011-8
Heinl M, Leitinger G, Tappeiner U (2012) Diurnal surface temperature regimes in mountain environments. Phys Geogr 33:344–359. https://doi.org/10.2747/2F0272-3646.33.4.344
Herbst M, Eschenbach C, Kappen L (1999) Water use in neighbouring stands of beech (Fagus sylvatica L.) and black alder (Alnus glutinosa (L.) Gaertn.) Annals Forest Sci 56:107–120. https://doi.org/10.1051/forest:19990203
Hiltbrunner E, Aerts R, Bühlmann T, Huss-Danell K, Magnusson B, Myrold DD, Reed SC, Sugurdsson BD, Körner C (2014) Ecological consequences of the expansion of N2-fixing plants in cold biomes. Oecologia 176:11–24. https://doi.org/10.1007/s00442-014-2991-x
Huber B, Frehner M (2013) Die Verbreitung und Entwicklung der Grünerlenbestände in der Ostschweiz. Schweizer Zeitschr Forstw 164:87–94. https://doi.org/10.3188/szf.2013.0087
Hothorn T, Bretz F, Westfall P (2008) Simultaneous inference in general parametric models. Biom J 50:346–363. https://doi.org/10.1002/bimj.200810425
Inauen N, Körner C, Hiltbrunner E (2013) Hydrological consequences of declining land use and elevated CO2 in Alpine grassland. J Ecol 101:86–96. https://doi.org/10.1111/1365-2745.12029
Johansson T (2000) Biomass equations for determining fractions of common and grey alders growing on abandoned farmland and some practical implications. Biomass Bioenergy 18:147–159. https://doi.org/10.1016/S0961-9534(99)00078-1
Jones HG (2014) Plants and microclimate. A quantative approach to environmental plant physiology. Cambridge University Press. Third edition
Kelliher FM, Leuning R, Schulze ED (1993) Evaporation and canopy characteristics of coniferous forests and grasslands. Oecologia 95:153–163. https://doi.org/10.1007/BF00323485
Knapp AK, Briggs JM, Collins SL, Archer SR, Bret-Harte MS, Ewers BE, Peters DB, Young DR, Shaver GR, Pendall E, Cleary MB (2008) Shrub encroachment in North American grasslands: shifts in growth form dominance rapidly alters control of ecosystem carbon inputs. Glob Chang Biol 14:615–623. https://doi.org/10.1111/j.1365-2486.2007.01512.x
Körner C (1994) Leaf diffusive conductances in the major vegetation types of the globe. In: Schulze ED, Caldwell MM (eds) Ecophysiology of photosynthesis. Ecol Studies 100:463–490, Springer, Berlin
Körner C (2007) Climatic treelines: conventions, global patterns, causes. Erdkunde:316–324. https://doi.org/10.3112/erdkunde.2007.04.02
Körner C, Nakhutsrishvili G (1986) Der Einfluss der Schafbeweidung auf den Wasserhaushalt der Vegetation. In: Nakhutsrishvili G, Cernusca A, Rabotnoff AT, Chezuriani LD (eds) Ökologische Untersuchungen an den Hochgebirgswiesen von Kazbegi. Mezniereba, Tbilisi, pp 99–120
Körner C, Jussel U, Schiffer K (1978) Transpiration, Diffusionswiderstand und Wasserpotential in verschiedenen Schichten eines Grünerlenbestandes. In: Cernusca A (ed) Ökologische Analysen von Almflächen im Gasteiner Tal. Veröff Österr MaB-Hochgebirgsprogramm Hohe Tauern 2. Universitätsverlag Wagner, Innsbruck, pp 81–98
Körner C, Wieser G, Cernusca A (1989) Der Wasserhaushalt waldfreier Gebiete in den österreichischen Alpen zwischen 600 und 2600 m Höhe. Struktur und Funktion von Graslandbkösystemen im Nationalpark Hohe Tauern. Veröff Österr MaB-Hochgebirgsprogramm Hohe Tauern 13. Universitätsverlag Wagner, Innsbruck, pp 119–153
Larcher W (2012) Bioclimatic temperatures in the high alps. In: Lütz C (ed) Plants in alpine regions. Springer, Wien, pp 21–27
Leuzinger S, Körner C (2007) Tree species diversity affects canopy leaf temperatures in a mature temperate forest. Agric For Meteorol 146:29–37. https://doi.org/10.1016/j.agrformet.2007.05.007
Lorup JK, Refsgaard JC, Mazvimavi D (1998) Assessing the effect of land use change on catchment runoff by combined use of statistical tests and hydrological modelling: case studies from Zimbabwe. J Hydrol 205:147–163. https://doi.org/10.1016/S0168-1176(97)00311-9
MacDonald D, Crabtree J, Wiesinger G, Dax T, Stamou N, Fleury P, Gutierrez Lazpita J, Gibon A (2000) Agricultural abandonment in mountain areas of Europe: environmental consequences and policy response. J Environ Manag 59:47–69. https://doi.org/10.1006/jema.1999.0335
Maestre FT, Bowker MA, Puche MD, Belén Hinojosa M, Martínez I, García-Palacios P, Castillo AP, Soliveres S, Luzuriaga AL, Sánchez AP, Carreira JA, Gallardo A, Escudero A (2009) Shrub encroachment can reverse desertification in semi-arid Mediterranean grasslands. Ecol Lett 12:930–941. https://doi.org/10.1111/j.1461-0248.2009.01352.x
Markart G, Kohl B, Kirnbauer R, Pirkl, Bertle H, Stern R, Reiterer A, Zanetti P (2006) Surface runoff in a torrent catchment area in middle Europe and its prevention. Geotech Geol Eng 24:1403–1424. https://doi.org/10.1007/s10706-005-2633-5
Montané F, Rovira P, Casals P (2007) Shrub encroachment into mesic mountain grasslands in the Iberian peninsula: effects of plant quality and temperature on soil C and N stocks. Glob Biogeochem Cycles 21. https://doi.org/10.1029/2006GB002853
Morgan JA, Milchunas DG, LeCain DR, West M, Mosier AR (2007) Carbon dioxide enrichment alters plant community structure and accelerates shrub growth in the shortgrass steppe. Proc Natl Acad Sci 104:14724–14729. https://doi.org/10.1073/pnas.0703427104
Moore GW, Bond JB, Jones JA (2011) A comparison of annual transpiration and productivity in monoculture and mixed-species Douglas-fir and red alder stands. For Ecol Manage 262:2263–2270. https://doi.org/10.1016/j.foreco.2011.08.018
Müller MH, Weingartner R, Alewell C (2013) Importance of vegetation, topography and flow paths for water transit times of base flow in alpine headwater catchments. Hydrol Earth Syst Sci 17:1661–1679. https://doi.org/10.5194/hess-17-1661-2013
Navarro LM, Pereira HM (2012) Rewilding abandoned landscapes in Europe. Ecosystems 15:900–912. https://doi.org/10.1007/s10021-012-9558-7
Obojes N, Bahn M, Tasser E, Walde J, Inauen N, Hiltbrunner E, Saccone P, Lochet J, Clément JC, Lavorel S, Tappeiner U, Körner C (2014) Vegetation effects on the water balance of mountain grasslands depend on climatic conditions. Ecohydrology 8:552–569. https://doi.org/10.1002/eco.1524
Pinheiro J, Bates D, DebRoy S, Sarkar D, R Development Core Team (2011) nlme: linear and nonlinear mixed effects models. R Package Version 3:1–102 http://cran.r-project.org/web/packages/nlme/index.html
R Development Core Team (2017) R: a language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. URL https://www.R-project.org/.
Rahman K, da Silva AG, Tejeda EM, Gobiet A, Beniston M, Lehmann A (2015) An independent and combined effect analysis of land use and climate change in the upper Rhone River watershed, Switzerland. Appl Geogr 63:264–272. https://doi.org/10.1016/j.apgeog.2015.06.021
Roques KG, O'connor TG, Watkinson AR (2001) Dynamics of shrub encroachment in an African savanna: relative influences of fire, herbivory, rainfall and density dependence. J Appl Ecol 38:268–280. https://doi.org/10.1046/j.1365-2664.2001.00567.x
Sakuratani T (1981) A heat balance method for measuring water flux in the stem of intact plants. J Agric Met 37:9–17. https://doi.org/10.2480/agrmet.37.9
Sakuratani T (1984) Improvement of the probe for measuring water flow rate in intact plants with the stem heat balance method. J Agric Met 40:273–277. https://doi.org/10.2480/agrmet.40.273
Scherrer D, Körner C (2009) Infra-red thermometry of alpine landscapes challenges climatic warming projections. Glob Chang Biol 16:2602–2613. https://doi.org/10.1111/j.1365-2486.2009.02122.x
Schleppi P (2010) Forested Water Catchments in a Changing Environment. In: Bredemeier M., Cohen S., Godbold D., Lode E., Pichler V., Schleppi P. (eds) Forest Management and the Water Cycle. Ecological Studies (Analysis and Synthesis), vol 212. Springer, Dordrecht
Schoch W, Heller I, Schweingruber FH, Kienast F (2004) Wood anatomy of central European species. www.woodanatomy.ch. Accessed 2016, April 2
Scholes R, Archer S (1997) Tree-grass interactions in savannas. Annu Rev Ecol Syst 28:517–544. https://doi.org/10.1146/annurev.ecolsys.28.1.517
Sturm M, Racine C, Tape K (2001) Climate change: increasing shrub abundance in the Arctic. Nature 411:546–547. https://doi.org/10.1038/35079180
Tape KEN, Sturm M, Racine C (2006) The evidence for shrub expansion in northern Alaska and the Pan-Arctic. Glob Change Biol 12:686–702. https://doi.org/10.1111/j.1365-2486.2006.01128.x
Tappeiner U, Cernusca A (1993) Alpine meadows and pastures after abandonment. Results of the Austrian MaB-programme and the EC-STEP project INTEGRALP. Pirineos 141:97–118. https://doi.org/10.3989/pirineos.1993.v141-142.166
Tappeiner U, Cernusca A (1998) Effects of land-use changes in the alps on exchange processes (CO2, H2O) in grassland ecosystems. In: Kovar K, Tappeiner U, Peters NE, Craig RG (Eds.), Hydrology, water resources and ecology in headwaters. IAHS publication. International Association of Hydrological Sciences, Wallingford, 131–138
Tasser E, Mader M, Tappeiner U (2003) Effects of land use in alpine grasslands on the probability of landslides. Basic Appl Ecol 4:271–280. https://doi.org/10.1078/1439-1791-00153
Tasser E, Tappeiner U, Cernusca A (2005) Ecological effects of land-use changes in the European alps. Global Change and Mountain Regions:409–420
Van Auken OW (2000) Shrub invasions of North American semiarid grasslands. Annu Rev Ecol Syst 31:197–215. https://doi.org/10.1146/annurev.ecolsys.31.1.197
Van den Bergh T, Inauen N, Hiltbrunner E, Körner C (2013) Climate and plant cover co-determine the elevational reduction in evapotranspiration in the Swiss Alps. J Hydrol 500:75–83. https://doi.org/10.1016/j.jhydrol.2013.07.013
Van den Bergh T (2017) Hydrological consequences of grassland abandonment along an elevational gradient in the Swiss Alps. PhD thesis (in press) University of Basel, Switzerland
Viviroli D, Weingartner R (2004) The hydrological significance of mountains: from regional to global scale. Hydrol Earth Syst Sci 8:1017–1030
Wood SJ, Jones DA, Moore RJ (2000) Accuracy of rainfall measurement for scales of hydrological interest. Hydrol Earth Syst Sci 4:531–543. https://hal.archives-ouvertes.fr/hal-00304684
Acknowledgments
The authors thank T. Bühlmann, G. Gisler, A. Huder and T. Zehnder for help with the field work. We thank D. Matays for the leaf conductance measurements during his college project in 2012. The Korporation Ursern provided access to the different sites and the Alpine Research and Education station Furka ALPFOR (http://www.alpfor.ch/) provided the necessary infrastructure.
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The project was supported by the Swiss National Science Foundation (grant CR30I3-124809/1 VALUrsern).
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Editor:Luis Lassaletta.
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van den Bergh, T., Körner, C. & Hiltbrunner, E. Alnus shrub expansion increases evapotranspiration in the Swiss Alps. Reg Environ Change 18, 1375–1385 (2018). https://doi.org/10.1007/s10113-017-1246-x
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DOI: https://doi.org/10.1007/s10113-017-1246-x