272
H. Dutta
more tolerant towards higher temperatures than natives. Thus, during ocean warming
scenarios, there is increased growth and survival of the early stages of aliens in
such communities, compared with the natives. This in turn aids in the subsequent
competitive interactions and community development (Cascade et al. 2010). High
temperature and carbon dioxide level also accelerate the growth rates of the invasive
aquatic dioecious plant hydrilla (Hydrilla verticillata) and enables it to spread more
rapidly within and outside of its current range (Chen et al. 1994). The populations of
another invasive species the common reed, Phragmites australis have also been found
to increase under elevated ambient air temperatures (Wilcox et al. 2003). The three
well known European invasive aquatic plants Hydrocotyle ranunculoides, Ludwigia
grandiflora and Myriophyllum aquaticum prefer high light intensity and temperature
and are expected propagate well under climate change (Hussner 2009).
Climate change eliminates cold temperature or winter hypoxia that hampers survival. Its effects result in the construction of greater number of reservoirs that serve
as hotspots for invasive species. Such consequences increase the possibility of establishment of new species. Another impact of climate change is flood, which helps in
the transportation of invasive species to newer sites (Rahel and Olden 2008). This
is much relevant with respect to the invasive weed Mimosa pigra because its dispersal is mainly affected by flooding and rainfall in Australia (Lonsdale 1993). In
fact floods play an important role because the seeds of wetland invasive plant seeds
are frequently dispersed by water (Zedler and Kercher 2004). Other effects of global
warming such salinity rise and oceanographic forcing also enhance biological invasions (Raitsos et al. 2010). Warming can also increase in the number of sexual versus
asexual reproductive periods and thus lead to greater rates of spread of aquatic invasive species (USEPA 2008). In addition, due to warming, the expansion of parapatric
species may occur into new habitats, which in turn can have detrimental impacts
similar to those of invasive species (Rahel et al. 2008).
As a whole, rising temperatures have modified the available thermal habitat of
warm-water species and thus, facilitated their settlement rapidly. The rate of alien
species invasion due to global warming has been more than the rate of temperature
rise. This has triggered severe threats to Mediterranean Sea biodiversity (Raitsos et al.
2010). Climate change has also been projected to severely intensify species invasion
in the Arctic and the Southern Ocean (Cheung et al. 2009). In fact, in the Arctic,
climate change and increased anthropogenic activities are likely to accelerate the
introduction of alien species (Chan et al. 2019). Thus, under the influence of climate
change new prevention and control strategies might be required to control invasive
species that at present exert only moderate effects or are limited by unfavorable
climatic conditions (Rahel and Olden 2008).
The negative effect of climate change can be understood from the fact that fish
communities dominated by cold-water species (physiological optima <20 °C) in
temperate regions are at the risk of displacement by non-native cool-water (physiological optima 20–28 °C) and warm-water fishes (physiological optima >28 °C).
Warming enables such fishes to invade by decreasing the thermal constraints on the
expression of their life history traits (Britton et al. 2010). In the context of fishes, the
H. Dutta
more tolerant towards higher temperatures than natives. Thus, during ocean warming
scenarios, there is increased growth and survival of the early stages of aliens in
such communities, compared with the natives. This in turn aids in the subsequent
competitive interactions and community development (Cascade et al. 2010). High
temperature and carbon dioxide level also accelerate the growth rates of the invasive
aquatic dioecious plant hydrilla (Hydrilla verticillata) and enables it to spread more
rapidly within and outside of its current range (Chen et al. 1994). The populations of
another invasive species the common reed, Phragmites australis have also been found
to increase under elevated ambient air temperatures (Wilcox et al. 2003). The three
well known European invasive aquatic plants Hydrocotyle ranunculoides, Ludwigia
grandiflora and Myriophyllum aquaticum prefer high light intensity and temperature
and are expected propagate well under climate change (Hussner 2009).
Climate change eliminates cold temperature or winter hypoxia that hampers survival. Its effects result in the construction of greater number of reservoirs that serve
as hotspots for invasive species. Such consequences increase the possibility of establishment of new species. Another impact of climate change is flood, which helps in
the transportation of invasive species to newer sites (Rahel and Olden 2008). This
is much relevant with respect to the invasive weed Mimosa pigra because its dispersal is mainly affected by flooding and rainfall in Australia (Lonsdale 1993). In
fact floods play an important role because the seeds of wetland invasive plant seeds
are frequently dispersed by water (Zedler and Kercher 2004). Other effects of global
warming such salinity rise and oceanographic forcing also enhance biological invasions (Raitsos et al. 2010). Warming can also increase in the number of sexual versus
asexual reproductive periods and thus lead to greater rates of spread of aquatic invasive species (USEPA 2008). In addition, due to warming, the expansion of parapatric
species may occur into new habitats, which in turn can have detrimental impacts
similar to those of invasive species (Rahel et al. 2008).
As a whole, rising temperatures have modified the available thermal habitat of
warm-water species and thus, facilitated their settlement rapidly. The rate of alien
species invasion due to global warming has been more than the rate of temperature
rise. This has triggered severe threats to Mediterranean Sea biodiversity (Raitsos et al.
2010). Climate change has also been projected to severely intensify species invasion
in the Arctic and the Southern Ocean (Cheung et al. 2009). In fact, in the Arctic,
climate change and increased anthropogenic activities are likely to accelerate the
introduction of alien species (Chan et al. 2019). Thus, under the influence of climate
change new prevention and control strategies might be required to control invasive
species that at present exert only moderate effects or are limited by unfavorable
climatic conditions (Rahel and Olden 2008).
The negative effect of climate change can be understood from the fact that fish
communities dominated by cold-water species (physiological optima <20 °C) in
temperate regions are at the risk of displacement by non-native cool-water (physiological optima 20–28 °C) and warm-water fishes (physiological optima >28 °C).
Warming enables such fishes to invade by decreasing the thermal constraints on the
expression of their life history traits (Britton et al. 2010). In the context of fishes, the