Alarm: Climate change ripping holes into the network of life

“Species diversity is just as important as the climate when we think about feeding humanity, but we lack the detailed regional and temporal data on flora and fauna that enable us to make better predictions on how ecosystems will develop,” explains Josef Settele from the Helmholtz Centre for Environmental Research – UFZ. The EU project called ALARM has created an initial overview of key habitats in Europe and their specific problems.

ALARM stands for “Assessing LArge scale environmental Risks for biodiversity with tested Methods”. Scientists and researchers from 35 countries and 68 partner organisations (including seven mostly small and medium-sized companies) worked on this comprehensive research project between 2004 and 2009 coordinated by Settele and six colleagues. Together, they have, for the first time, developed uniform methods for assessing quantitative data on the environmental risks for biodiversity in various landscapes in Europe. One of the driving factors is the regional impact of climate change, which forces flora and fauna to adapt extremely quickly to new conditions.

Furthermore, climate change encourages invasions by alien animal and plant species that may displace indigenous species and can cause substantial damage as harmful weeds or pests in woods and fields, thereby leading to substantial costs, plus ever more soil sealing, increasing fragmentation of landscapes and habitats caused by an ever tighter network of roads and the intensification of agriculture. Environmental chemicals from farming and industry often exert a subtle influence on the reproduction rates of insects and invertebrates which, in turn, are eaten by vertebrates, such as birds. It is the interaction between all these factors that is decisive and triggers species loss. “The question of whether climate change is good or bad for the species cannot be answered in this sense. There are winners and losers. However, of the 300 or so European butterflies thatwe studied, some 70 benefited, while the other 230 tended not to,” says Settele.

Pollinating insects, such as bees, bumblebees, hoverflies and butterflies play a decisive role for the ecosystems. That the pollination levels in many landscapes in Europe have fallen strongly has been observed over a longer period of time. In the case of crops, this leads to harvest losses, in the case of wild plants it means less offspring all the way through to threats for survival. Although wheat, oat and rye are pollinated by the wind, fruit trees, hazelnut bushes and other vitamin suppliers are dependent on insects for forming the fruits. “We cannot say what a bee is worth, but we can say what it contributes,” believes Josef Settele, thereby calculating: “All the pollinator-dependant fruits, nuts and herbs and spices on the world market in 2005 would have cost around 153 billion euros.”

ALARM has made it possible for the first time to catalogue the spread of many pollinating insects in greater detail. The problems faced by beekeepers with their colonies of bees have been known for some time, but now information on wild insects, such as bees, bumblebees, hover flies and butterflies is being added. “The problem is that we previously lacked good data, above all on the more common species, such as the Peacock Butterfly and Small Tortoiseshell, which are not so interesting for specialised colleagues,” explains Settele. This is why the UFZ researchers have organised a network of volunteers together with the Gesellschaft für Schmetterlingsschutz (GfS). These volunteers regularly walk along specific routes and count the butterflies (www.tagfalter-monitoring.de). The first analyses indicate that 2009 was a relatively good year for many butterflies – but some usually more common species such as the small tortoiseshell were observed less frequently. The mass invasion of the Painted Lady also gave the general public the impression that it had been a good year for butterflies.

The collected results on the risks for biodiversity will be published in an atlas in early 2010. In this atlas, ALARM researchers have also combined the distribution areas of certain plants with the IPCC climate scenarios and land use maps to identify where certain butterflies will continue to have good chances of survival in the future. Some butterfly species, such as the Dusky Large Blue, only survive under unique symbiotic conditions which call for specific meadows or certain harvesting regimes. “These maps show us where it would be worth looking carefully. And we also see where nature conservation management could be transferred from south to north if the climate change continues.” A bright idea that Settele and a team of international colleagues now wants to pursue in the research project called CLIMIT.