Ecological responses to recent climate change' EX NATURE?

http://eebweb.arizona.edu/courses/Ecol206/Walther%20et%20al%20Nature%202002.pdf


PART REPRODUCED BELOW OF MUCH LARGER ARTICLE: GS



Ecological responses to recent climate
change
Gian-Reto Walther*, Eric Post², Peter Convey³, Annette Menzel§, Camille Parmesank, Trevor J. C. Beebee¶, Jean-Marc Fromentin#,
Ove Hoegh-Guldberg
I
& Franz Bairlein**
* Institute of Geobotany, University of Hannover, Nienburger Str. 17, 30167 Hannover, Germany
² Department of Biology, The Pennsylvania State University, 208 Mueller Lab, University Park, Pennsylvania 16802, USA
³ British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge CB3 0ET, UK
§ Department of Ecology, Technical University Munich, Am Hochanger 13, 85354 Freising, Germany
k Integrative Biology, Patterson Labs 141, University of Texas, Austin, Texas 78712, USA
¶ School of Biological Sciences, University of Sussex, Falmer, Brighton BN1 9QG, UK
# IFREMER, Centre Halieutique MeÂditerraneÂen et Tropical, Bvld Jean Monnet, BP 171, 34203 SeÁte Cedex, France
I
Centre for Marine Studies, University of Queensland, St Lucia, 4072 Queensland, Australia
** Institute for Avian Research `Vogelwarte Helgoland', An der Vogelwarte 21, 26386 Wilhelmshaven, Germany
............................................................................................................................................................................................................................................................................
There is now ample evidence of the ecological impacts of recent climate change, from polar terrestrial to tropical marine
environments. The responses of both ¯ora and fauna span an array of ecosystems and organizational hierarchies, from the species
to the community levels. Despite continued uncertainty as to community and ecosystem trajectories under global change, our
review exposes a coherent pattern of ecological change across systems. Although we are only at an early stage in the projected
trends of global warming, ecological responses to recent climate change are already clearly visible.
T
he Earth's climate has warmed by approximately 0.6 8C
over the past 100 years with two main periods of
warming, between 1910 and 1945 and from 1976
onwards. The rate of warming during the latter period
has been approximately double that of the ®rst and, thus,
greater than at any other time during the last 1,000 years
1
. Organ-
isms, populations and ecological communities do not, however,
respond to approximated global averages. Rather, regional changes,
which are highly spatially heterogeneous (Fig. 1), are more relevant
in the context of ecological response to climatic change. In many
regions there is an asymmetry in the warming that undoubtedly will
contribute to heterogeneity in ecological dynamics across systems.
Diurnal temperature ranges have decreased because minimum
temperatures are increasing at about twice the rate of maximum
temperatures. As a consequence, the freeze-free periods in most
mid- and high-latitude regions are lengthening and satellite data
reveal a 10% decrease in snow cover and ice extent since the late
1960s. Changes in the precipitation regime have also been neither
spatially nor temporally uniform (Fig. 1). In the mid- and high
latitudes of the Northern Hemisphere a decadal increase of 0.5±1%
mostly occurs in autumn and winter whereas, in the sub-tropics,
precipitation generally decreases by about 0.3% per decade
1
.
There is now ample evidence that these recent climatic changes
have affected a broad range of organisms with diverse geographical
distributions
2±6
. We assess these observations using a process-
oriented approach and present an integrated synopsis across the
major taxonomic groups, covering most of the biomes on Earth. We
focus on the consequences of thirty years of warming at the end of
the twentieth century, and review the responses in (1) the phenology
and physiology of organisms, (2) the range and distribution of
species, (3) the composition of and interactions within commu-
nities, and (4) the structure and dynamics of ecosystems, high-
lighting common and contrasting features amongst the taxa and
systems considered.
Phenology
PhenologyÐthe timing of seasonal activities of animals and
plantsÐis perhaps the simplest process in which to track changes
in the ecology of species in response to climate change. Birds,
butter¯ies and wild plants, in particular, include popular and easily
identi®able species and thus have received considerable attention
from the public. As a result many long-term phenological data sets
have been collected. Studies in Europe and North America have
revealed phenological trends that very probably re¯ect responses to
recent climate change
7,8
. Common changes in the timing of spring
activities include earlier breeding or ®rst singing of birds, earlier
arrival of migrant birds, earlier appearance of butter¯ies, earlier
choruses and spawning in amphibians and earlier shooting and
¯owering of plants (Fig. 2). In general, spring activities have
occurred progressively earlier since the 1960s (Table 1).
Some evidence also indicates a later onset of autumnal phenolo-