The Phenology Network is a charity organisation that has been recording the first sightings/buddings/flowerings of different species since the 18th century. It was founded by Robert Marsham in 1736 and was carried on by his family until 1958. Marsham recorded 27 different events for over 20 different species, i.e. the first snowdrop flowering, the first migratory birds arriving and the first croak of the frog [1].
Since then, hundreds of other people have recorded similar events over the last two centuries either as a hobby or as a volunteer of the Woodland Trust and/or Royal Meteorology Society. These events have been recorded all over the UK and can be used to identify changes in flowering and migration dates of many different species as an indicator of climate change. Scientists have used this data to build up a record of these events over the last 250 years. Amano et al published a paper on changes in flowering dates in the past 250 years and how climate has affected these [2]. It was calculated that each 1 degree increase in temperature meant plants flowered 5 days earlier on average.
The first flowering of plants and budding of trees can greatly affect whole ecosystems. Some migratory birds rely on climate to time their migration periods, however most species of birds time their migration with day length. As day length doesn’t change with temperature rise, most migratory birds are still migrating on the same day they always have and therefore are at risk of prey having already been eaten due to the earlier migration of other birds. This can indirectly cause shifts in distribution of species as they become more dominant in areas where prey is available at a later date.
References:
[2] Amano, T, R. Smithers, T. Sparks and W. Sutherland (2011), 'A 250-year index of first flowering dates and its response to temperature changes', Proceedings of the Royal Society, 277, 2451-2457.
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