Climate change, impacts and vulnerability in Europe ... - MemoFin.fr

Climate impacts on environmental systems3.4.3 Animal phenologyRelevanceClimate warming affects the life-cycles of all animalspecies. Species adapted to warmer temperaturesor dryer conditions may benefit from this change,whereas cold-adapted species may encounterincreasing pressure on their life-cycles. Mild wintersand the earlier onset of spring allow for an earlieronset of reproduction and, in some species, thedevelopment of extra generations during the year.In the case of a phenological decoupling betweeninteracting species in an ecosystem (e.g. reducedpressure from parasitoids and predators), certainpopulations may reach very high abundances thatattain orexceed damage thresholds in managedecosystems (e.g. bark beetles in conifer forests, Baieret al., 2007). Desynchronisation of phenologicalevents may also directly reduce fitness, for exampleif shortened hibernation times deteriorate bodycondition (Reading, 2007) or if interactions betweenherbivores and host plants are lost (Visser andHolleman, 2001). It may also negatively affectecosystem services such as pollination (Heglandet al., 2009; Schweiger et al., 2010). There is robustevidence that generalist species with high adaptivecapacity are favoured, whereas specialist specieswill be mostly affected negatively (Schweiger et al.,2008, 2012; Roberts et al., 2011).Past trendsSeveral studies have convincingly demonstrated atight dependency of life-cycle traits of animals withambient temperatures, both in terrestrial and aquatichabitats (Roy and Sparks, 2000; Stefanescu et al.,2003; Dell et al., 2005; Parmesan, 2006; Hassall et al.,2007; Dingemanse and Kalkman, 2008; Schlüteret al., 2010; Tryjanowski et al., 2010). Mostly, theobserved warming leads to an advanced timing oflife history events. For example, temporal trends forappearance dates of two insect species (honey bee,small white: Pieris rapae) in more than 1 000 localitiesin Spain have closely followed variations in recordedspring temperatures between 1952 and 2004 (Gordoand Sanz, 2006a).The predicted egg-laying date for the Pied flycatcher(Ficedula hypoleuca) showed significant advancementbetween 1980 and 2004 in western and central Europe,but delays in northern Europe, both depending onregional temperature trends in the relevant season(Both and Marvelde, 2007) (see Map 3.12). Data fromfour monitoring stations in south to mid-Norwaythat include nest-boxes of Pied flycatcher from 1992–2011 show in contrary to the regional temperatureestimated trends that there are no significant delaysin egg-laying date for the Pied flycatcher, but anannual fluctuation making a rather flat curve for themedian over these years (Framstad, 2012). A study inthe Netherlands covering the period between 1932and 2004 found that half of the investigated birdspecies are now overwintering significantly closer totheir breeding site than in the past, most likely dueto warmer winters (Visser et al., 2009). A long-termtrend analysis of 110 common breeding birds acrossEurope (1980–2005, 20 countries) showed that specieswith the lowest thermal maxima showed the sharpestdeclining trends in abundance (Jiguet et al., 2010). Inother words, cold-adapted species are losing territorymost quickly.A study from the United Kingdom found that eachof the 44 species of butterfly investigated advancedits date of first appearance since 1976 (Diamondet al., 2011). Recent studies on birds, butterflies andamphibians not only confirmed previous findingsthat there is a coherent fingerprint of climate changein the pattern of phenological changes (Crick andSparks, 1999; Root et al., 2003; Charmantier et al.,2008), but also indicated that average rates ofphenological change have recently accelerated inline with accelerated warming trends (Thackerayet al., 2010). There is also increasing evidence aboutclimate-induced changes in spring and autumnmigration, including formerly migratory birdspecies becoming resident (Gordo and Sanz, 2006b;Jonzén et al., 2006; Rubolini et al., 2007).Key messages: 3.4.3 Animal phenology• Many animal groups have advanced their life-cycles in recent decades, including frogs spawning, birdsnesting and the arrival of migrant birds and butterflies. This advancement is attributed primarily to awarming climate.• The breeding season of many thermophilic insects (such as butterflies, dragonflies and bark beetles)has been lengthening, allowing more generations to be produced per year.• The observed trends are expected to continue in the future but quantitative projections are ratheruncertain.Climate change, impacts and vulnerability in Europe 2012133