02200nas a2200253   4500008004100000020001400041245008500055210006900140260001200209300001600221490000800237520151400245653001401759653001901773653001701792653001301809653001601822653001901838100001701857700001701874700001501891700001601906856002401922       2009                        eng d  a0030-129900aThe distribution and abundance of animal populations in a climate of uncertainty0 adistribution and abundance of animal populations in a climate of  c2009///  a1121 - 11260 v1183 aCurrent predictions regarding the ecological consequences of climate change on animal populations are generally autecological and species-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 - 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 habitats; (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 ecosystem structure and function10aABUNDANCE10aCLIMATE-CHANGE10aCONSEQUENCES10aPATTERNS10aPOPULATIONS10aTROPHIC LEVELS1 aBerggren, A.1 aBjorkman, C.1 aBylund, H.1 aAyres, M.P.  uISI:000268535300001