Algemeen

It's summer wildflower season in the Rocky Mountains, a time when high-peaks meadows are dotted with riotous color. But for how long? Once, wildflower season in montane meadow ecosystems extended throughout the summer months. But now scientists have found a fall-off in wildflowers at mid-season. They published their results, funded by the National Science Foundation (NSF), in the current issue of the Journal of Ecology."Shifts in flowering in mountain meadows could in turn affect the resources available to pollinators like bees," says David Inouye of the University of Maryland, currently on leave in NSF's Division of Environmental Biology.

A guide to more than 100 of Britain’s arable plants says flowers that were once common are now rare sights because of increasingly intensive farming methods. Those species most at risk in Scotland include shepherd’s needle Scandix pecten-veneris, which is fast disappearing in East Lothian, pink dianthus, geranium and yellow globe flower Trollius europaeus. Other species, such as corncockle Agrostemma githago, are already considered to be extinct in Britain. Also threatened are common poppies, corn marigold and cornflower. Wildflower experts said farmers were using increasing amounts of pesticides and other chemicals, cutting back hedges and filling in boggy areas where plants thrived. This has also had a knock-on effect on bees, butterflies and birds further up the food chain.

Small-scale farmers can double food production within 10 years in critical regions by using ecological methods, a new UN report shows. Based on an extensive review of the recent scientific literature, the study calls for a fundamental shift towards agroecology as a way to boost food production and improve the situation of the poorest.

A mixture of chemicals found in modern pesticides may be killing bee colonies around the world, according to a United Nations report. The report says that the highly toxic chemicals in the insecticides, collectively known as neonicotinoids, can cause loss of the sense of direction and memory on which bees rely to find food. The United Nations Environment Programme (UNEP) report says that when neonicotinoids are combined with certain fungicides, the toxicity becomes a thousand times stronger. It says that the loss of nature’s most important plant pollinators could undermine efforts to feed the world’s growing population. The report finds that tens of thousands of plant species could be lost in coming years unless conservation efforts are stepped up.

Despite widespread concern about declines in pollination services, little is known about the patterns of change in most pollinator assemblages. By studying bee and hoverfly assemblages in Britain and the Netherlands, we found evidence of declines (pre-versus post-1980) in local bee diversity in both countries; however, divergent trends were observed in hoverflies. Depending on the assemblage and location, pollinator declines were most frequent in habitat and flower specialists, in univoltine species, and/or in nonmigrants. In conjunction with this evidence, outcrossing plant species that are reliant on the declining pollinators have themselves declined relative to other plant species. Taken together, these findings strongly suggest a causal connection between local extinctions of functionally linked plant and pollinator species.

Imidacloprid can be applied as a systemic insecticide to trees by direct stem injections or by soil injections and drenches, and be indirectly introduced to aquatic systems via leaf fall or leaching, which may pose a risk to natural decomposer organisms. When applied directly to aquatic microcosms to simulate leaching from soils, imidacloprid was shown to be highly toxic to aquatic insects. Imidacloprid at realistic field concentrations in maple leaves had adverse effects on aquatic insects and earthworms. Imidacloprid at realistic concentrations in leaves can inhibit leaf litter breakdown through adverse effects on decomposer invertebrates. When imidacloprid is applied as a systemic insecticide to the soil around trees it may cause adverse effects on earthworms.