Reproductive and physiological responses to simulated climate warming for four subalpine species

Abstract

* The carbon costs of reproduction were examined in four subalpine herbaceous plant species for which number and size of flowers respond differently under a long-term infrared warming experiment. * Instantaneous measurements of gas exchange and an integrative model were used to calculate whole-plant carbon budgets and reproductive effort (RE). * Of the two species for which flowering was reduced, only one (Delphinium nuttallianum) exhibited higher RE under warming. The other species (Erythronium grandiflorum) flowers earlier when freezing events under warming treatment could have damaged floral buds. Of the two species for which flowering rates were not reduced, one (Helianthella quinquenervis) had higher RE, while RE was unaffected for the other (Erigeron speciosus). Each of these different responses was the result of a different combination of changes in organ size and physiological rates in each of the species. * Results show that the magnitude and direction of responses to warming differ greatly among species. Such results demonstrate the importance of examining multiple species to understand the complex interactions among physiological and reproductive responses to climate change.

Short-term signals of climate change along an altitudinal gradient in the South Alps

“…Dullinger et al (2004) demonstrated the essential role of dispersal and recruitment traits for the invasion pattern of P. mugo in alpine grasslands, to be at least as important as climatic changes. The inter-annual variability (Holtmeier and Broll 2005) and mainly the availability of viable seeds 'superimposed on microtopography and edaphic conditions' (Kullman 2007) are major driving forces for the establishment and advance of woody species. The process of expansion from the outposts onwards or even downwards to the treeline was described as 'filling rather than moving' (Grabherr et al 1995).…”

“…Several studies already revealed considerable alterations of species richness in high alpine mountains (Hofer 1992;Gottfried et al 1994;Grabherr et al 1994;Pauli et al 1996Pauli et al , 2001aPauli et al , 2007Virtanen et al 2003, Walther et al 2005aParolo and Rossi 2008). Shifting of vegetation belts as well as of the distribution ranges of species has already been proven for European mountains (Walther et al 2001(Walther et al , 2002Klanderud and Birks 2003;Moiseev and Shiyatov 2003;Parmesan and Yohe 2003;Peñuelas and Boada 2003;Walther 2003;Dierschke 2005;Dobbertin et al 2005;Walther et al 2005b;Kapralov et al 2006;Kullman 2007;Holzinger et al 2008); these phenomena are predicted to continue in the future (Lenoir et al 2008). Mountain ranges with low altitude such as the northern Apennine might lose up to 50% of their actual species number until 2100 (Rossi and Parolo 2005).…”

Responses of high‐altitude graminoids and soil fungi to 20 years of experimental warming

“…Effects of warming on abiotic conditions were strongest in the upper blocks . Responses of non-graminoids and ecosystem processes are reported elsewhere , Price and Waser 1998, 2000, Saleska et al 1999, de Valpine and Harte 2001, Shaw and Harte 2001, Perfors et al 2003, Lambrecht et al 2007). We next examined individual species responses along the belt transect.…”

Climate change effects on vegetation in the Pacific Northwest: a review and synthesis of the scientific literature and simulation model projections

“…Tree ring studies have linked decadal trends in past tree growth rates to decadal fl uctuations in summer temperatures (Graumlich et al 1989, Peterson andPeterson 2001), but it is unclear how much summer temperatures could increase before growth became limited by other factors (e.g., soil water). Experimental tests of warming and CO 2 enrichment effects suggest that responses differ among species, which could also infl uence community structure (Dawes et al 2011, Lambrecht et al 2007). …”