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Oikos 118: 1121Á1126, 2009 doi: 10.1111/j.1600-0706.2009.17558.x, # 2009 The Authors. Journal compilation # 2009 Oikos Subject Editor: Karin Johst. Accepted 17 March 2009

The distribution and of animal in a climate of uncertainty

A˚ sa Berggren, Christer Bjo¨rkman, Helena Bylund and Matthew P. Ayres

A˚. Berggren ([email protected]), C. Bjo¨rkman and H. Bylund, Dept of , PO Box 7044, Swedish Univ. of Agricultural Sciences, SEÁ75007 Uppsala, Sweden. Á M. P. Ayres, Dept of Biological Sciences, Dartmouth College, 103 Gilman Hall, Hanover, NH 03755, USA.

Current predictions regarding the ecological consequences of climate change on animal populations are generally autecological and -specific, and/or non-mechanistic extrapolations of recent short-term patterns. To better understand and predict the effects of climate change on the distribution of species and the abundance of populations we offer a novel, broad theoretical framework. Climate-induced changes in trophic structure may actually be more predictable than effects on individual species. The logic is that there are general differences in climatic sensitivity among trophic levels Á specifically, that as one moves up trophic levels, there is an increase in the temperature sensitivity of vital rates. More precisely, we provide: (1) a formal mathematical definition of distribution limits that is both operational and conceptual, introducing the concept DL50, defined as the geographic and climatic isoline representing an equilibrium occupancy of half of the suitable ; (2) a matrix of the possible changes in trophic structure from climate change and the general theoretical consequences; and (3) a new idea that predicts broad effects of climatic warming on trophic systems. Our intention is to help meet the challenge of developing and testing general theoretical models that can predict which species will be winners and losers in ecological time, which evolutionary traits will be favoured or selected against, and what will be consequences for structure and function.

Understanding the biological and environmental factors Biotic and abiotic effects on that limit the distribution and abundance of organisms is fundamental to ecology (Andrewartha and Birch 1954). Accumulating studies have shown a link between recent The great difficulty of explaining and predicting distribu- climate change and species distributions. For example, tion and changes from climate change calls for butterfly species distributions in North America and Europe novel theoretical and empirical approaches (Parmesan et al. have shifted northwards and to higher altitudes (Parmesan 2005). In an effort to meet this need, we consider here the 1996, Mikkola 1997, Franco et al. 2006, Wilson et al. general concepts and theories that are relevant to the 2007), several species of notable forest pests have recently processes of population and the state of species increased their outbreak range into colder latitudes (Battisti distributions. One objective is to identify key knowledge et al. 2005, Tran et al. 2007, Jepsen et al. 2008, Raffa et al. gaps and provide a focus for future research by providing 2008), and some analyses have predicted that outright conceptual models. We believe that our suggestions are will be frequent (Thomas et al. 2004, Sekercioglu reasonably general, but the applicability is most clear for et al. 2008). Nonetheless, there is little general theory that invertebrateÁplant systems at mid to high latitudes, which is considers how climate change will jointly affect the abiotic our focus here. To begin, we consider a simple model of the and biotic factors that determine species distribution. Maybe hierarchical levels that are involved and their general biotic changes that follow from the abiotic changes will affect connections. The properties of an ecological species more than the initial abiotic changes? We need a arise from its species composition, which is a product of better understanding of the absolute and relative importance species distributions that are themselves a product of abiotic of abiotic versus biotic factors on species distributions (Suttle and biotic factors (climate and species interactions). The et al. 2007). For example, a species might be able to persistent regional presence of a species requires the physiologically tolerate a change of one degree Celsius, but maintenance of viable populations in the area. not the from a new species that could invade the system due to that temperature change. To predict possible changes in species distribution due to a change in climate, The review of and decision to publish this paper has been taken by the above there is also a need to combine population dynamic processes mentioned SE. The decision by the handling SE is shared by a second SE and the with theories of (Holt et al. 2005). EiC.

1121 Climate change can affect individuals with consequences of interactions with other species (e.g. increased competi- for demographics. Weather variables, such as temperature, tion from newly present species exceeds the demongraphic rain and wind, may affect physiological and behavioural benefits of increased fecundity in a warmer abiotic system). performance (e.g. survival, reproduction and movement Contrary to the scenario of concordant geographic shifts (Dixon and McKay 1970, Mason and Hopper 1997). The in whole communities, it seems more probable that species many facets of climate change (e.g. changes of means, within contemporary communities will respond individua- minimums, maximums and the variability of temperature) listically to climatic change (Graham et al. 1996, Thuiller can have different effects on individuals within the same et al. 2008) If so, community composition will be dynamic species, and different species can be differentially affected by within process-zones where new assemblages permitted by the same changes (Davis et al. 1998, Virtanen and climatic change will be filtered by community interactions Neuvonen 1999a, Stireman et al. 2005). When a changed into a subset that is relatively stable in ecological time. The climate in one region has different autecological effects on resulting new communities may be more or less stable the ability of various species to maintain viable populations, depending upon the rate of climatic change relative to this necessarily leads to a change in the potential species demographic responses of the component species. Process- composition of the community. Interactions among species, zones should be most easily observed along the distribution both within trophic levels (e.g. competition and ) edges of (Ellison et al. 2005) and and among trophic levels (e.g. herbivory, and . ) are well known as important determinants of species abilities to maintain viable populations and colonise new areas. Thus, the newly realized community will be a Estimating and measuring distribution product of autecological effects along with the outcome of species interactions. Further, variation among species in Ecologists have been studying species distributions since their demographic and physiological responses to abiotic long before discussions of climate change (Rapaport 1982) factors will likely affect the outcome of species interactions, and there exist numerous sophisticated analytical techniques e.g. changes in predation rate (Wilmers et al. 2006). The for handling point or grid data describing abundance or combination of direct effects from abiotic change and presence/absence (Austin 2002, Fortin et al. 2005, Jacquez indirect effects from community interactions (Fig. 1, et al. 2008). In some cases, the models are explicitly spatial, Petchey et al. 1999), will ultimately determine the new with latitude and longitude as predictors. In other cases, pattern of species distributions (Sutherst et al. 2007). climatic variables are used as the predictors and resulting The process of a climatically induced change in species maps are derived from geographic patterns in the climatic distribution can be divided into three phases: 1) the current drivers (Foody 2008). With respect to the challenge of understanding climatic effects on species distribution limits, distribution area (D0 when climate change starts), 2) the future distribution area where there is a process-zone at a chief problem is that we lack detailed information about the distribution of most of the world’s species (with birds which the distribution is changing (Dn) and 3) the future and butterflies being notable exceptions; Parmesan 2006, final distribution area (Dend), assuming a period with no further directional change in climate. The different phases Sekercioglu et al. 2008). Furthermore, even for relatively and the process can be viewed as an infinite series of well known species, distribution data are frequently spatially establishments, where the edge of the distribution at any coarse relative to the dynamics of interest, which may be on time t, is determined by abiotic and biotic factors. The scale of tens of km near the distribution edges. Finally, abiotic factors set a definite maximum distribution limit, although statistical methods exist for delineating boundaries e.g. a minimum temperature point that individuals of the from suitable data, statistics to describe the movement and species can survive (Tran et al. 2007). The biotic constraints fuzziness of species edges are still not well developed (Fortin will be the cumulative effect of positive and negative effects et al. 2005, Jacquez et al. 2008). Here, we suggest a very simple generalizable approach for measuring distribution limits (especially of invertebrates) as it may be influenced by climate change. Suitable data will require repeated sampling of preferred habitats within and adjacent to the known Predator distribution. This would permit characterization of occu- Direct effects Indirect pancy dynamics at the distribution edge due to patterns of effects dispersal, colonisations and extinctions (Fig. 2). Species within and among guilds could be compared with respect to Climate their occupancy of habitats among years and among replicate transects that cross the same (longitudinal or altitudinal) bioclimatic transition zone. Given such data, the average species distribution limit for a species could be Plants operationally quantified as the latitude or altitude at which suitable patches are occupied half as frequently as in the Figure 1. Changes in climate variables may affect species both distribution centre (DL50 in Fig. 3). A second parameter directly (e.g. increased development rate of eggs with warmer (e.g. b1 in Fig. 3) could characterize the fuzziness of temperatures for a focal species) and indirectly (e.g. decreased the distribution edge, i.e. the range of latitudes and long- ability of a parasite species to match an egg-laying window, which itudes over which processes of colonisation, establishment reduces its attack rate on its host species. and local are strong demographic forces. We

1122 resulting data would permit more satisfying descriptions of distribution limits than have generally been obtained.

Effects of climate warming on trophic systems: physiology

There could be some predictable patterns among species Latitude groups in their sensitivity to changes in the abiotic environment. If so, this could permit generalisations regarding community and ecosystem responses. One pos- sibility is that sensitivity to temperature tends to increase Longitude with (Fig. 4). Plant growth tends to increase year 1 with temperature at mid to high latitudes (Norby and Luo year 2 2004), but growth increases are attenuated because respira- year 3 year 4 tion, and especially photorespiration, increase more sharply with increasing temperature than does gross , Figure 2. Presence ( ) and absence ( ) in patches at and therefore net photosynthesis tends to be a decelerating different latitudes and longitudes will create distribution limit lines function with a maximum that can be within the range of that likely will vary among years and species. experienced temperatures (Luo 2007). In contrast, the consumption rates and development rates of poikilothermic herbivores tend to increase steeply (e.g. doubling over hypothesize that the responsiveness of distribution limits to :108C) across the full range of regularly experienced climate change will sometimes be predictably similar within temperatures (Bale et al. 2002). This presumably contri- groups of species as defined by histories, trophic levels, butes to patterns in contemporary and geological time of and landscape pattern of suitable habitats (Holt et al. 2005). increasing abundance of insect herbivores with increasing Actualising such a sampling program would require careful temperatures (Reynolds et al. 2007, Wilf 2008). Finally, consideration of the size and spacing of habitats to be poikilothermic predators of insect herbivores generally sampled, and sampling effort within study sites, but the depend on mobility (usually including flight) search for prey items. Movement, especially flight, requires high physiological performance of musculature, which is gen- erally facilitated by warm temperatures (Heinrich 1993, Harrison and Roberts 2000). If the temperature sensitivity of prey searching performance is generally higher than the temperature sensitivity of consumption by herbivores, this would contribute to increasing top down controls of herbivory with increasing temperature. The rare studies of temperature effects on hostÁparasitoid interactions have reported that parasitoid populations exert stronger effects

Figure 3. A generalized operational model for defining distribu- tion limits with respect to latitude based on the probability of patch occupancy. A two parameter function (e.g. logistic) could be fit to data from replicated presence/absence surveys. DL50 represents the latitude (or location with respect to any relevant bioclimatic gradient) in which the focal species is present in half of the observations. A steep slope near DL50 indicates a relatively abrupt distribution edge (DL10 not far from DL90); the slope will Figure 4. A conceptual model regarding the effects of increased tend to be shallower, and the variance in o greater, for populations temperature on poikilothermic species belonging to different whose occupancy patterns are more strongly influenced by factors trophic levels. Compared to herbivores, the vital rates of plants independent of the climatic gradient (e.g. stochastic colonisation may be generally less responsive to temperature (because of high and extinction events). Directional changes in distributions could temperature sensitivity of photorespiration), and the vital rates of be quantified (with confidence intervals) as the rate of change in predators may be generally more responsive (because of high DL50. temperature sensitivity of mobility and prey searching success).

1123 on their insect hosts at higher temperatures (Campbell et al. level or functional groups within trophic level, then there 1974, Virtanen and Neuvonen 1999b). This increased will be predictable changes in ecosystem function as species efficiency of parasitoids occurs despite that a shorter are added to the regional pool. Furthermore, trophic development time in the host results in a narrower time linkage systems will tend to change because generalist window for attacking vulnerable prey instars or stages. consumers and generalist predators can be expected to Furthermore, an increase in temperature may influence expand their distributions more readily than specialist plants such that they produce tissue of lower nutritional consumers and predators, who will sometimes be con- quality for herbivores, which increases consumption re- strained by slow colonisation rates of the species on which quirements for herbivores, and therefore tends to increase they depend. As a result of species differences in colonisa- their exposure to predators (Emmerson et al. 2004). On the tion rates, we can expect ecosystem structure of mid to high other hand, changes in food quality may in some insect latitude systems to, at times, move towards new equilibria herbivores also affect their ability to defend themselves and often be subject to persistent transient dynamics. against natural enemies and hence increase their survival. For example substances reducing the food quality may also be used by the in antipredator defence (Bjo¨rkman General predictions and Larsson 1991) or positively affect immunocompetence in the herbivore (Kapari et al. 2006, but cf. Klemola et al. There are likely to be consequences for biological commu- 2008). This illustrates the complexity and difficulties of nities and of transient dynamics and shifting predicting the outcome of tritrophic interactions. To our equilibria in the wake of climate change. We should expect knowledge, the model presented in Fig. 4 has not been that some historically stable species interactions will collapse subjected to explicit tests, but there is supporting evidence while new ones appear. There could be some relatively rapid from a European grassland system of increasing sensitivity evolutionary responses driven by pressure from abiotic with increasing trophic level to climatic variation in general changes in combination with new biotic interactions and (Voigt et al. 2003, 2007), and evidence from marine relationships (Thomas et al. 2001). In some cases these systems that warming strengthens herbivoreÁplant interac- ecological and evolutionary changes will affect species tions (O’Connor 2009). persistence, ecosystem processes and services, and human activities (Ayres and Lombardero 2000, de Wit and Stankiewics 2006). Also, there will likely be cases of Effect of climate warming on trophic systems: evolutionary changes in species morphologies and beha- colonisation dynamics viours, and changes in population structure that influence evolutionary processes (Thomas et al. 2001, Andrew and Species with the greatest dispersal ability will be those with Hughes 2007, Vanhanen et al. 2007). The challenge is to the greatest potential for rapid expansion of their distribu- develop and test general theoretical models that can predict tions in response to climatic amelioration. This would which species will be winners and losers in ecological time, generally include larger species, species that can fly and and which evolutionary traits will be favoured or selected species whose movements are not heavily constrained by a against in evolutionary time. patchy distribution of preferred habitats (Warren et al. 2001, Menende´z et al. 2006). For species where the increased ability to disperse is more rapid than changes in Directions for future research environmental suitability there will tend to be an increase in the number and extent of sink populations. Alternatively, Today’s climate change can be compared with previous for species where dispersal is slow relative to the rate at periods of global change that resulted in high extinction which new environments become suitable for reproduction, rates (Mayhew et al. 2008). However, now the change is there will tend to be an increase in the number of suitable unfolding in our presence, which provides opportunities for but unoccupied habitats. Differences in dispersal abilities, real-time scientific observation and hopefully for appro- in combination with directional climate change, should priate anticipation, mitigation, and adaptation by human produce new community constellations. Those species with society. There has been much progress since ecologists relatively high dispersal rates would tend to be released from began to seriously study the effects of contemporary climate inter-specific interactions that were important in their change, but there remain fundamental gaps in our knowl- historic ranges, and those with relatively low dispersal rates edge of how species populations and distributions are will tend to be increasingly impacted by newly arriving affected by climate change. We can be sure that multiple species that were previously excluded by the climate. There theories will be needed. Here, we focused on terrestrial will likely be general consequences for the trophic structure plantÁinvertebrate systems at mid to high latitudes. There if there are tendencies for different colonisation abilities of remains a need for theories that apply to low latitudes that plants versus herbivores versus predators. embrace aquatic, marine, and belowground ecosystems, and The rate at which distribution limits for a given species that are also relevant to terrestrial systems strongly affected can expand with climatic amelioration will be influenced by by vertebrates. A priori, it seems likely that homeothermic (1) the rate at which newly available habitats are reached by species (mainly birds and mammals) will be fundamentally dispersing individuals and (2) the probability that dispersers different from poikilotherms in their response to climate will establish and maintain a population. Presumably change, and that temperature will be less important as a species vary in these attributes. If the variance in colonisa- driver of change in tropical systems than, for example, tion ability is predictably structured with respect to trophic changes in moisture (Ritchie et al. 2008). Regardless of the

1124 ecosystem there would be high value in identifying general de Wit, M. and Stankiewics, J. 2006. Changes in surface water tendencies for changes in trophic structure. supply across Africa with predicted climate change. Á Science Efficient tests of theories will frequently require experi- 311: 1917Á1921. mental studies where environmental variables can be Dixon, A. F. G. and McKay, S. 1970. Aggregation in the sycamore controlled. Because there are too many species to study aphid Drepanosiphum platanoides (Schr.) (Hemiptera: Aphidi- dae) and its relevance to regulation of population growth. Á J. more than a tiny subset in detail, the thoughtful choice of Anim. Ecol. 39: 439Á454. study species will facilitate progress. Considerations could Ellison, A. M. et al. 2005. Loss of foundation species consequences include the following: 1) species with different dispersal for the structure and dynamics of forested ecosystems. capabilities (e.g. related species with different percentage of Á Frontiers Ecol. Environ. 3: 479Á486. flight capable individuals), 2) species likely to be different in Emmerson, M. et al. 2004. How does global change affect the their sensitivity towards abiotic factors (e.g. related species strength of trophic interactions? Á Basic Appl. Ecol. 5: 505Á with present distribution at different latitudes), and 3) 514. species likely to be different in their competitive ability and Foody, G. M. 2008. Refining predictions of climate change strength of interactions with other trophic levels. Useful impacts on plant species distribution through the use of local study systems are likely to be found in areas where new statistics. Á Ecol. Inf. 3: 228Á236. Fortin, M-J. et al. 2005. Species’ geographic ranges and distribu- habitats emerge as a result of global change. For example, tional limits: pattern analysis and statistical issues. Á Oikos newly created habitats at edges of species distributions, non- 108: 7Á17. colonised habitat patches at higher altitudes, distribution Franco, A. M. A. et al. 2006. Impacts if climate warming and edges of invading species and areas where humans introduce habitat loss on extinctions at species’ low-latitude range exotics. We believe that there are already many data sets for boundaries. Á Global Change Biol. 12: 1545Á1553. various organisms and systems that could be used to evaluate Graham, R. W. et al. 1996. Spatial response of mammals to late general hypotheses such as those presented in this paper. The quaternary environmental fluctuations. Á Science 272: 1601Á most likely sources of information are long-term studies of 1607. , communities, and ecosystems. Mu- Harrison, J. F. and Roberts, S. P. 2000. Flight respiration and seums are another . There is basic and applied value energetics. Á Annu. Rev. Physiol. 62: 179Á205. Á in exploiting existing information to evaluate newly emer- Heinrich, B. 1993. The hot-blooded insects. Harvard Univ. Press. ging hypotheses as we race to understand, predict and pre- Holt, R. D. et al. 2005. Theoretical models of species’ borders. emptively respond to ecological responses to climate change. Single species approaches. Á Oikos 108: 18Á27. Jacquez, G. M. et al. 2008. Preface to the special issue on spatial statistics for boundary and patch analysis. Á Environ. Ecol. Acknowledgements Á The authors thank Stig Larsson for valuable Stat. 15: 365Á367. discussions. CB received support by Formas and the Eu-project Jepsen, J. U. et al. 2008. Climate change and outbreaks of the BACCARA. MPA was supported by NSF DEB-0316522. geometrids Operophtera brumata and Epirrita autumnata in subarctic birch forest: evidence of a recent outbreak range expansion. Á J. Anim. Ecol. 77: 257Á264. Kapari, L. et al. 2006. Defoliating insect immune defense interacts References with induced plant defense during a population outbreak. Á Ecology 87: 291Á296. Andrew, N. R. and Hughes, L. 2007. Potential host colonization Klemola et al. 2008. Host plamt quality and defence against by insect herbivores in a warmer climate: a transplant parasitoids: no relationship between levels of parasitism and a experiment. Á Global Change Biol. 13: 1539Á1549. geometrid defoliator immunoassay. Á Oikos 177: 926Á934. Andrewartha, H. G. and Birch, L. C. 1954. The distribution and Luo, Y. Q. 2007. Terrestrial carbon-cycle feedback to climate abundance of animals. Á Univ. of Chicago Press. warming. Á Annu. Rev. Ecol. Evol. Syst. 38: 683Á712. Austin, M. P. 2002. Spatial prediction of species distribution: an Mason, P. G. and Hopper, K. R. 1997. Temperature dependence interface between ecological theory and statistical modelling. in locomotion of the parasitoid Aphelinus asychis (Hymenop- Á Ecol. Modell. 157: 101Á118. tera: Aphelinidae) from geographical regions with different Ayres, M. and Lombardero, M. J. 2000. Assessing the con- climates. Á Environ. Entomol. 26: 1416Á1423. sequences of global change for forest from Mayhew, P. J. et al. 2008. A long-term association between global herbivores and pathogens. Á Sci. Total. Environ. 262: 263Á temperature and , origination and extinction in the 286. fossil record. Á Proc. R. Soc. Lond. B 275: 47Á53. Bale, J. S. et al. 2002. Herbivory in global climate change research: Menende´z, R. et al. 2006. changes lag behind direct effects of rising temperature on insect herbivores. climate change. Á Proc. R. Soc. Lond. B 273: 1465Á1470. Á Global Change Biol. 8: 1Á16. Mikkola, K. 1997. Population trends of Finnish Lepidoptera Battisti, A. et al. 2005. Expansion of geographic range in the pine during 1961Á1996. Á Entomol. Fenn. 8: 121Á143. processionary moth caused by increased winter temperatures. Norby, R. J. and Luo, Y. Q. 2004. Evaluating ecosystem responses Á Ecol. Appl. 15: 2084Á2096. to rising atmospheric CO2 and global warming in a multi- Bjo¨rkman, C. and Larsson, S. 1991. Pine sawfly defence and factor world. Á New Phytol. 162: 281Á293. variation in host plant resin acids: a tradeoff with growth. O’Connor, M. I. 2009. Warming strengthens an herbivore-plant Á Ecol. Entomol. 16: 283Á289. interaction. Á Ecology 90: 388Á398. Campbell, A. et al. 1974. Temperature requirements of some Parmesan, C. 1996. Climate and species’ range. Á Nature 382: aphids and their parasites. Á J. Appl. Ecol. 11: 431Á438. 765Á766. Davis, A. J. et al. 1998. Making mistakes when predicting shifts in Parmesan, C. 2006. Ecological and evolutionary responses to species range in response to global warming. Á Nature 391: recent climate change. Á Annu. Rev. Ecol. Evol. Syst. 37: 637Á 783Á786. 669.

1125 Parmesan, C. et al. 2005. Empirical perspectives on species Tran, J. K. et al. 2007. Impact of minimum winter temperatures borders: from traditional to global change. on the population dynamics of Dendroctonus frontalis. Á Ecol. Á Oikos 108: 58Á75. Appl. 17: 882Á899. Petchey, O. L. et al. 1999. Environmental warming alters food- Vanhanen, H. et al. 2007. Climate change and range shifts in two webz structure and ecosystem function. Á Nature 402: 69Á72. insect defoliators: gypsy moth and nun moth Á a model study. Raffa, K. F. et al. 2008. Cross-scale drivers of natural disturbances Á Silva Fenn. 41: 621Á638. prone to anthropogenic amplification: the dynamics of bark Virtanen, T. and Neuvonen, S. 1999a. Climate change and beetle eruptions. Á Bioscience 58: 501Á517. lepidopteran biodiversity in Finland. Á Global Change Sci. 1: Rapaport, E. H. 1982. Areography: geographical strategies of 439Á448. species. Á Pergaman Press. Virtanen, T. and Neuvonen, S. 1999b. Performance of moth Reynolds, L. V. et al. 2007. Climatic effects on caterpillar larvae on birch in relation to altitude, climate, host quality and fluctuations in northern hardwood forests. Á Can. J. For. parasitoids. Á Oecologia 120: 92Á101. Res. 37: 481Á491. Voigt, W. et al. 2003. Trophic levels are differentially sensitive to Ritchie, E. G. et al. 2008. Large-herbivore distribution and climate. Á Ecology 84: 2444Á2453. abundance: intra- and interspecific niche variation in the Voigt, W. et al. 2007. Using functional groups to investigate tropics. Á Ecol. Monogr. 78: 105Á122. community response to environmental changes: two grassland Sekercioglu, C. H. et al. 2008. Climate change, elevational range case studies. Á Global Change Biol. 13: 1710Á1721. shifts, and bird extinctions. Á Conserv. Biol. 22: 140Á150. Warren, M. S. et al. 2001. Rapid responses of British butterflies to Stireman, J. O. et al. 2005. Climatic unpredictability and parasitism of caterpillars: implications of global warming. opposing forces of climate and habitat change. Á Nature 414: Á Proc. Natl Acad. Sci. USA 102: 17384Á17387. 65Á69. Sutherst, R. W. et al. 2007. Including species interactions in risk Wilf, P. 2008. Insect-damaged fossil leaves record assessments for global change. Á Global Change Biol. 13: response to ancient climate change and extinction. Á New 1843Á1859. Phytol. 178: 486Á502. Suttle, K. B. et al. 2007. Species interactions reverse grassland Wilmers, C. C. et al. 2006. Predator disease out-break modulates responses to changing climate. Á Science 315: 640Á642. topÁdown, bottomÁup and climate effects on herbivore Thomas, C. D. et al. 2001. Ecological and evolutionary processes population dynamics. Á Ecol. Lett. 9: 383Á389. at expanding range margins. Á Nature 411: 577Á581. Wilson, R. J. et al. 2007. An elevational shift in butterfly species Thomas, C. D. et al. 2004. Extinction risk from climate change. richness and composition accompanying recent climate Á Nature 427: 145Á148. change. Á Global Change Biol. 13: 1873Á1887. Thuiller, W. et al. 2008. Predicting global change impacts on plant species’ distributions future challenges. Á Persp. Plant Ecol. Evol. Syst. 9: 137Á152.

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