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pattylou
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Biodiversity is affected through a variety of means. Landscaping with non-native plants that adapt well to a new climate, for example, can allow the non-native plant to spread at the expense of native plants. Ranching has led to problems in places such as Death Valley, a fragile ecosystem where hardy grasses that were originally introduced into neighboring ranges for sheep ranchers, have invaded and outcompeted indigenous and rare species within Death Valley itself.
Climate change may also be facilitating the loss of biodiversity.
In other words, warmer springs not only lengthens the growing season for farmers, but also allows some non-indigenous species (sea squirts, in this instance) to outcompete native species. The mean temperature throughout the year is of less importance than whether temperature is warmer, in the winters.
Climate change may also be facilitating the loss of biodiversity.
Linking climate change and biological invasions: Ocean warming facilitates nonindigenous species invasions.
Stachowicz JJ, Terwin JR, Whitlatch RB, Osman RW.
Section of Evolution and Ecology, University of California, Davis 95616, USA.
The spread of exotic species and climate change are among the most serious global environmental threats. Each independently causes considerable ecological damage, yet few data are available to assess whether changing climate might facilitate invasions by favoring introduced over native species. Here, we compare our long-term record of weekly sessile marine invertebrate recruitment with interannual variation in water temperature to assess the likely effect of climate change on the success and spread of introduced species. For the three most abundant introduced species of ascidian (sea squirt), the timing of the initiation of recruitment was strongly negatively correlated with winter water temperature, indicating that invaders arrived earlier in the season in years with warmer winters. Total recruitment of introduced species during the following summer also was positively correlated with winter water temperature. In contrast, the magnitude of native ascidian recruitment was negatively correlated with winter temperature (more recruitment in colder years) and the timing of native recruitment was unaffected. In manipulative laboratory experiments, two introduced compound ascidians grew faster than a native species, but only at temperatures near the maximum observed in summer. These data suggest that the greatest effects of climate change on biotic communities may be due to changing maximum and minimum temperatures rather than annual means. By giving introduced species an earlier start, and increasing the magnitude of their growth and recruitment relative to natives, global warming may facilitate a shift to dominance by nonnative species, accelerating the homogenization of the global biota.
In other words, warmer springs not only lengthens the growing season for farmers, but also allows some non-indigenous species (sea squirts, in this instance) to outcompete native species. The mean temperature throughout the year is of less importance than whether temperature is warmer, in the winters.