20 years ago phenology was a much derided topic, but there has since been a sea change in attitudes. It has become a major component of climate change impact studies providing key evidence for the IPCC.

I provide an overview of some of the changes taking place in phenology, in attitudes towards phenology, and in analytical approaches to phenology.

New directions in phenology research at macro-scales are presented, adopting a remote sensing approach. Analysis of time-series of satellite imagery provides important insights into vegetation phenology. Eleven years of of SPOT Vegetation NDVI were analysed for Northern China. An empirical link between temperature and vegetation phenology, and changes in vegetation productivity and vegetation phenology in Northern China were found.

Plant species differ in their capacity to adjust their flowering time to variation in temperature. Using historical records of the phenology and spatial distribution of British plant species, we have shown that those which track changes more closely (i.e., temporal climatic niche conservatism) show reduced northward and altitudinal range shifts and consequently lower spatial climatic niche conservatism.

Current species distribution models are mostly based on questionable correlations between occurrences and the climate. We used a process-based phenology model to predict the native and invasive range margins of common ragweed, a damaging weed with extremely allergic pollen. Our results show that integrating phenology into distribution models will be critical for the mechanistic modelling of range dynamics.

We analysed 78,497 flight dates of 27 UK butterflies, over 31 years of standardised monitoring, to quantify the latitudinal and temporal relationships with temperature.    All species showed a strong correlation between phenology and temperature over time - earlier emergences in warmer years.  However, temperature-related variation in phenology was significantly greater over time than over space suggesting strong local adaptation.

Climate change can influence the strength of species interactions by altering the phenology of the species involved. We investigated how temperature influences the phenological matching between several crucifer species (Brassicaceae), and one of their main herbivores (the Orange tip butterfly; Anthocharis cardamines) along a south-north latitudinal gradient in Sweden. We used experimental studies with four different temperature treatments.

Conspecific butterfly populations (Euphydryas editha) were faced with a choice of ovipositing on a chemically-defended, long-lived host, Pedicularis, or on a phenologically-defended ephemeral host, Collinsia.  At sites where Collinsia lifespan was relatively long, the insects evolved monophagy on Collinsia despite resulting mortality and phenological stress.  Where the lifespan of Collinsia was shorter, the butterflies had evolved preference for Pedicularis.

The long-running BTO nest record scheme comprises thousands of observations of first egg dates spanning many locations and species. I will show how we can use these data to identify the time-windows over which the phenology of different species is most sensitive to temperature and separate the contributions that plasticity and local adaptation make to geographic variation in phenology. 

A major concern about climate change is that reproductive timing gets increasingly mismatched with timing of food. Here we use long-term trends in selection on breeding date (1980-2008) from six populations of Ficedula flycatchers across Europe to evaluate fitness consequences of increased mismatches. Interestingly, selection intensified from 1980-1995, but thereafter relaxed again. This suggests recent adaptation to increased spring temperatures.

This study makes use of a satellite-based index of resource availability to explore how the level of seasonality and inter-annual variability in resource dynamics can affect birth season length of ungulate populations. Our findings provide new insights into the evolution of breeding synchrony in terrestrial mammals, enhancing our ability to predict the potential impacts of climate change on biodiversity.

To assess the influence of canopy phenological state on CO₂ flux, we installed two different digital camera systems on a flux measurement tower in an oak-dominated forest in southern England over two growing seasons.  We modelled daily Gross Primary Productivity (GPP) using the extracted colours to compare with the flux measurements and found the strong relationship between GPP and Hue.