Phenology and food webs in a changing climate

Our main focus in the Phenoweb project is on the effect of climate (spring temperature) on the map transect cropped moretiming (phenology) of key events that are critical to a woodland food web comprised of tree, caterpillar and blue tit. There is concern that climate change may lead to species interactions becoming mismatched, to the detriment of species further up the food chain, and we are interested in examining how this plays out on a landscape scale.

Since 2014 we have been collecting data on phenology and species interactions across 44 woodland sites (see map to left) that stretch 200km northwards from Edinburgh. This replication of woodland sites serves two purposes. First, the sites vary in temperature and this provides a window into the relationship between temperature and timings. Second, the sites vary in habitat and this allows us to examine how timings and their impacts on feeding relationships vary among habitats.

The major questions we are trying to address are:

1) How severe is the threat of climate change driven disruption of timings to blue tits?

This is a key step in establishing the risk that climate change poses to ephemeral food webs, with the blue tits serving as a model for organisms further up the food chain. There is abundant evidence that animals further up the food chain may struggle to adjust their timings enough to keep up with their prey, but we still lack evidence as to whether this negatively impacts on population size.

2) How buffered (resilient) are woodland food webs in the face of climate change?

A major focus of our work is on understanding the resilience of these food webs. bluetit_treeFor instance, can the loss of one feeding interaction be replaced by another? Or can a negative impact of climate change in one habitat be buffered by a more benign outcome in another? Answering these questions will be key to developing conservation strategies, such as recommendations about the benefits of planting different tree species.

3) Can we use space as a substitute for time to understand impacts of climate change?

Because it is difficult to collect long-term data, many of the scientific insights into how plants and animals will be impacted by climate change come from purely spatial studies, under the assumption that responses to climate in space can serve as a surrogate to those obtained over time. With long-term data we will be able to examine when this major but extremely widespread assumption holds and when it does not.