【生態】気候変動によって生態系の同調性が乱れる恐れ

Systematic variations in the sensitivity to climate change of species at different levels of the food chain are reported in a large-scale study published in Nature this week. These differences could result in widespread desynchronization of the seasonal timing of recurring biological events (phenology), which could in turn affect ecosystem function, the study suggests.

Various long-term ecological changes have been attributed to climate change, including the timing of phenological events such as reproduction and migration. Stephen Thackeray and colleagues analysed 10,003 data sets containing phenological information for 812 terrestrial and aquatic species representing three levels of the food chain (trophic levels) over the period 1960-2012. They matched these datasets with local temperature and precipitation data to quantify variation in climate sensitivity.

The authors show that the direction, magnitude and timing of climate sensitivity vary significantly among species in different taxonomic and trophic groups. In particular, secondary consumers (such as predatory birds, fish and mammals) were consistently less sensitive to climate variations than other groups. They forecast that by 2050, primary consumers (such as seed-eating birds and herbivorous insects) will have shifted their phenological events by more than twice as much as species at other trophic levels - an average of 6.2 versus 2.5-2.9 days earlier, although there is substantial variation among taxonomic groups. The findings highlight the importance of managing ecosystems within a ‘safe operating space’ with respect to the likely impacts of projected climate change, the authors conclude.