Ungulates Attenuate the Response of Mediterranean Mountain Vegetation to Climate Oscillations
In regions with a long-standing history of grazing pressure, vegetation has co-evolved with herbivores by developing intrinsic functional dynamics. Although this type of trophic interaction has been recognised as being important for shaping how vegetation responds to climate, better knowledge about how this process occurs on the landscape scale and over a long time range is necessary. Here, we evaluated the potential roles of herbivores in modulating the response of mountainous Mediterranean vegetation to seasonal and long-term climate oscillations. To understand the relations among climate, plants and animal population, we fitted a Bayesian model to a combination of long-term (1995–2014) climate datasets, satellite greenness maps (NASA Landsat NDVI) and exotic Barbary sheep census data (breeding success and abundance of Ammotragus lervia). We also used the intrinsic mode function and Hilbert spectrum transformations to decompose NDVI time series and to evaluate their periodic oscillations. We found remarkable dissimilarities as to how climate affects the temporal oscillation of vegetation greenness between landscapes both with and without ungulates, albeit their similarities under environmental conditions. Vegetation responses to climate are particularly attenuated in landscapes with ungulates, an effect that depends on ungulate population abundance. In a world where extreme climate events are becoming frequent and intense, our results indicate that ungulates can strongly modulate how grasslands and scrublands respond to climate change. Increasing our knowledge as to how this type of trophic interaction affects vegetation responses to climate variability is of much importance for managing ungulate rewilding strategies.
Keywordsherbivore ungulates exotic animals Normalised Difference Vegetation Index primary productivity plant biomass climate change climate adaptability
We are grateful to all the people who participated in the Barbary sheep census. This study was partially funded by the Projects CGL2015-66966-C2-1-2-R and RTI2018-099609-B-C21 (Spanish Ministry of Economy and Competitiveness and EU/ERDF) and Regional Government of Murcia, Spain (CARM).
- Deutsche Akademie der Naturforscher Leopoldina, editor. 2013. Trends in extreme weather events in Europe: implications for national and European Union adaptation strategies. Halle (Saale). EASAC policy report 22. ISBN: 978-3-8047-3239-1.Google Scholar
- Heidinger AK, Foster H Michael J, Walther A, Zhao X, NOAA CDR Program. 2014. NOAA Climate Data Record (CDR) of Reflectance and Brightness Temperatures from AVHRR Pathfinder Atmospheres-Extended (PATMOS-x). https://www.ngdc.noaa.gov/docucomp/page?xml=NOAA/NESDIS/NCDC/Geoportal/iso/xml/C00837. Last accessed 01/03/2018.
- Holmes EE, Ward EJ, Scheuerell MD. 2018. Analysis of multivariate time-series using the MARSS package. https://cran.r-project.org/web/packages/MARSS/vignettes/UserGuide.pdf. Last accessed 01/04/2018.
- Hunter MD, Price PW. 1992. Playing chutes and ladders: heterogeneity and the relative roles of bottom-up and top-down forces in natural communities. Ecology 73:724–32.Google Scholar
- Isbell F, Craven D, Connolly J, Loreau M, Schmid B, Beierkuhnlein C, Bezemer TM, Bonin C, Bruelheide H, de Luca E, Ebeling A, Griffin JN, Guo Q, Hautier Y, Hector A, Jentsch A, Kreyling J, Lanta V, Manning P, Meyer ST, Mori AS, Naeem S, Niklaus PA, Polley HW, Reich PB, Roscher C, Seabloom EW, Smith MD, Thakur MP, Tilman D, Tracy BF, van der Putten WH, van Ruijven J, Weigelt A, Weisser WW, Wilsey B, Eisenhauer N. 2015. Biodiversity increases the resistance of ecosystem productivity to climate extremes. Nature 526:574–7.PubMedCrossRefPubMedCentralGoogle Scholar
- Li L, Wang Y-P, Beringer J, Shi H, Cleverly J, Cheng L, Eamus D, Huete A, Hutley L, Lu X, Piao S, Zhang L, Zhang Y, Yu Q. 2017. Responses of LAI to rainfall explain contrasting sensitivities to carbon uptake between forest and non-forest ecosystems in Australia. Sci Rep 7:11720.PubMedPubMedCentralCrossRefGoogle Scholar
- Rivas-Martínez S. 1986. Mapas de las Series de Vegetación de España. Madrid: ICONA.Google Scholar
- Svenning J-C, Pedersen PBM, Donlan CJ, Ejrnæs R, Faurby S, Galetti M, Hansen DM, Sandel B, Sandom CJ, Terborgh JW, Vera FWM. 2016. Science for a wilder Anthropocene: synthesis and future directions for trophic rewilding research. Proc Natl Acad Sci 113:898–906.PubMedCrossRefPubMedCentralGoogle Scholar
- Yi C, Ricciuto D, Li R, Wolbeck J, Xu X, Nilsson M, Aires L, Albertson JD, Ammann C, Arain MA, de Araujo AC, Aubinet M, Aurela M, Barcza Z, Barr A, Berbigier P, Beringer J, Bernhofer C, Black AT, Bolstad PV, Bosveld FC, Broadmeadow MSJ, Buchmann N, Burns SP, Cellier P, Chen J, Chen J, Ciais P, Clement R, Cook BD, Curtis PS, Dail DB, Dellwik E, Delpierre N, Desai AR, Dore S, Dragoni D, Drake BG, Dufrêne E, Dunn A, Elbers J, Eugster W, Falk M, Feigenwinter C, Flanagan LB, Foken T, Frank J, Fuhrer J, Gianelle D, Goldstein A, Goulden M, Granier A, Grünwald T, Gu L, Guo H, Hammerle A, Han S, Hanan NP, Haszpra L, Heinesch B, Helfter C, Hendriks D, Hutley LB, Ibrom A, Jacobs C, Johansson T, Jongen M, Katul G, Kiely G, Klumpp K, Knohl A, Kolb T, Kutsch WL, Lafleur P, Laurila T, Leuning R, Lindroth A, Liu H, Loubet B, Manca G, Marek M, Margolis HA, Martin TA, Massman WJ, Matamala R, Matteucci G, McCaughey H, Merbold L, Meyers T, Migliavacca M, Miglietta F, Misson L, Mölder M, Moncrieff J, Monson RK, Montagnani L, Montes-Helu M, Moors E et al. 2010. Climate control of terrestrial carbon exchange across biomes and continents. Environ Res Lett 5:034007.CrossRefGoogle Scholar