Trends and temperature effects in the arrival of spring migrants in Portland (United Kingdom) 1959-2005

This paper examines the first arrival dates of 25 migrant bird species recorded at Portland, Dorset, UK, for the period 1959-2005. To determine if trends over time existed, linear regression of first arrival dates on year was used; initially for the whole period and subsequently separately for 1959-1981 and 1982-2005. First arrival dates were compared to spring temperatures along migration routes in southern Europe and France and in the UK. The arrival of 11 species (e.g. Sand Martin, Blackcap and Pied Flycatcher) was significantly earlier with the mean trend for all species showing an advance of 1.6 days/decade over the study period. Over all species, trends in first arrival date were not significantly different between the two time periods but there were differences for Turtle Dove, Whitethroat and Lesser Whitethroat. Monthly mean temperatures along the European part of the birds' migration route were generally negatively correlated with, but can only explain < 30% of the variability in, first arrival dates. The consequences of both a changed phenology and differential phenological changes between species require urgent investigation

Long-term effects of hedgerow management policies on resource provision for wildlife

Hedgerows provide important habitat and food resources for overwintering birds, mammals and invertebrates. Currently, 41% of managed hedgerow length in England forms part of three Agri-Environment Scheme (AES) options, which specify a reduction in hedgerow cutting frequency from the most common practice of annual cutting. These AES options aim to increase the availability of flowers and berries for wildlife, but there has been little rigorous testing of their efficacy or estimates of the magnitude of their effects. We conducted a factorial experiment on hawthorn hedges to test the effects of (i) cutting frequency (every 1, 2 or 3 years) and (ii) timing of cutting (autumn vs. winter) on the abundance of flowers and berry resources. Results from 5 years show that hedgerow cutting reduced the number of flowers by up to 75% and the biomass of berries available over winter by up to 83% compared to monitored uncut hedges. Reducing cutting frequency from every year to every 3 years resulted in 2.1 times more flowers and a 3.4 times greater berry mass over 5 years. Cutting every 2 years had an intermediate effect on flower and berry abundance, but the increase in biomass of berries depended on cutting in winter rather than autumn. The most popular AES option is cutting every 2 years (32% of English managed hedgerow length). If these hedges were managed under a 3 year cutting regime instead, we estimate that biomass of berries would increase by about 40%, resulting in a substantial benefit for wildlife

Increased migration of Lepidoptera linked to climate change

The number of species of migratory Lepidoptera (moths and butterflies) reported each year at a site in the south of the UK has been rising steadily. This number is very strongly linked to rising temperatures in SW Europe. It is anticipated that further climate warming within Europe will increase the numbers of migratory Lepidoptera reaching the UK and the consequences of this invasion need urgent attention