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S. Chatterjee and A. Tandon
shift in biomes will be irreversible. Some species may be eliminated entirely, coldadapted systems (e.g. arctic and alpine communities) may turn into warming, and
low-elevated islands may disappear due to sea level rise. It will be a great challenge
for the existing species for their survival in the new ecosystem because their migration or shift will be drawn from the existing condition and ultimately “fittest” will
“survive”. Climate change has occurred many times throughout the Earth’s history,
but the increasing anthropogenic activities during the last few decades are amplifying
the ecological impacts of the current climate alterations.
4.1 Effect and Consequences of Climate Change
on Ecosystem and on Biodiversity
The multivariate factors of climate change are supposed to have an effect on all
the levels of biodiversity, starting from organism to biome levels (Parmesan 2006).
Ecosystem functioning and resilience are affected due to decrease in genetic diversity as climate change is forcing the population for directional selection and rapid
migration (Botkin et al. 2007; Meyers and Bull 2002). Disappearance of around
6300 species among the 9650 interspecific systems, including pollinators and parasites, suggested that along with individual species extinction, associated species
extinction is also a major concern (Koh et al. 2004). Due to gradual climate change
phenological shifts are happening in flowering plants and insect pollinators. Plant
and pollinator populations do not fit well with each other which may lead to the
destruction of structure of plant-pollinator networks, resulting in extinctions of both
the species (Kiers et al. 2010; Rafferty and Ives 2010). At a higher level of biodiversity, vegetation communities are influenced by climate related changes and shifting
of 5–20% of Earth’s terrestrial ecosystems, in particular cool conifer forests, tundra, scrubland, savannahs, and boreal forest has been anticipated in the Millennium
Ecosystem Assessment (Sala et al. 2005). Extensive studies have been done on this
subject during the last few decades (Peters and Lovejoy 1994; Lovejoy and Hannah
2006; Willis and Bhagwat 2009) and were summarized in various reports (Gitay
et al. 2002; Steffen et al. 2010; Karl et al. 2009; Millennium Ecosystem Assessment 2005a, b). It is predicted that in distant future a major part of the Amazonian
rainforest could be taken over by tropical savannahs (Lapola et al. 2009); at higher
altitudes and latitudes, alpine and boreal forests might expand towards north by shifting their tree lines upwards by outlaying low stature tundra and alpine communities
(Alo and Wang 2008). Global temperature rise will warm up the oceans which will
increase the acid level and consequently tropical coral reefs will be degraded soon
(Hoegh-Guldberg et al. 2007).
At present the most concerning issue is extinction because “Life once lost-lost forever”. Climate change affects species individually (Root et al. 2003) and as a community as well. While calculating the extinction risk, ‘suitable habitat’ and ‘weak habitat
specificity’ are the main issues to be considered. But sometimes species enters into
S. Chatterjee and A. Tandon
shift in biomes will be irreversible. Some species may be eliminated entirely, coldadapted systems (e.g. arctic and alpine communities) may turn into warming, and
low-elevated islands may disappear due to sea level rise. It will be a great challenge
for the existing species for their survival in the new ecosystem because their migration or shift will be drawn from the existing condition and ultimately “fittest” will
“survive”. Climate change has occurred many times throughout the Earth’s history,
but the increasing anthropogenic activities during the last few decades are amplifying
the ecological impacts of the current climate alterations.
4.1 Effect and Consequences of Climate Change
on Ecosystem and on Biodiversity
The multivariate factors of climate change are supposed to have an effect on all
the levels of biodiversity, starting from organism to biome levels (Parmesan 2006).
Ecosystem functioning and resilience are affected due to decrease in genetic diversity as climate change is forcing the population for directional selection and rapid
migration (Botkin et al. 2007; Meyers and Bull 2002). Disappearance of around
6300 species among the 9650 interspecific systems, including pollinators and parasites, suggested that along with individual species extinction, associated species
extinction is also a major concern (Koh et al. 2004). Due to gradual climate change
phenological shifts are happening in flowering plants and insect pollinators. Plant
and pollinator populations do not fit well with each other which may lead to the
destruction of structure of plant-pollinator networks, resulting in extinctions of both
the species (Kiers et al. 2010; Rafferty and Ives 2010). At a higher level of biodiversity, vegetation communities are influenced by climate related changes and shifting
of 5–20% of Earth’s terrestrial ecosystems, in particular cool conifer forests, tundra, scrubland, savannahs, and boreal forest has been anticipated in the Millennium
Ecosystem Assessment (Sala et al. 2005). Extensive studies have been done on this
subject during the last few decades (Peters and Lovejoy 1994; Lovejoy and Hannah
2006; Willis and Bhagwat 2009) and were summarized in various reports (Gitay
et al. 2002; Steffen et al. 2010; Karl et al. 2009; Millennium Ecosystem Assessment 2005a, b). It is predicted that in distant future a major part of the Amazonian
rainforest could be taken over by tropical savannahs (Lapola et al. 2009); at higher
altitudes and latitudes, alpine and boreal forests might expand towards north by shifting their tree lines upwards by outlaying low stature tundra and alpine communities
(Alo and Wang 2008). Global temperature rise will warm up the oceans which will
increase the acid level and consequently tropical coral reefs will be degraded soon
(Hoegh-Guldberg et al. 2007).
At present the most concerning issue is extinction because “Life once lost-lost forever”. Climate change affects species individually (Root et al. 2003) and as a community as well. While calculating the extinction risk, ‘suitable habitat’ and ‘weak habitat
specificity’ are the main issues to be considered. But sometimes species enters into