Invertebrate ecology and biogeography

Dr Tim Shreeve

 
Our work is contributing to the understanding of the processes by which organisms adapt to complex and heterogeneous environments. This is important because rapid environmental change is greatly affecting the frequency and distribution of many insect species. To meet national and international biodiversity targets, it is critical to know how species and communities have responded to past changes and how they will respond to future changes. We primarily work on butterflies, which are an indicator taxon of environmental quality and change.

Projects

1. Conservation ecology of butterflies
We work on the ecology and conservation of butterflies. As an example we have a collaborative research project (with Butterfly Conservation) focused on the Wall brown butterfly (Lasiommata megera) which has been lost from 72% of former sites in the last 25 years. Declines have been more severe in the south than elsewhere. We are examining microhabitat use, adult activity and changes of abundance in relation to weather. This will help us understand its decline and precisely describe what it requires to maintain viable populations.

Even on very good sites the key microhabitats it needs to maintain adequate body temperatures for flight activity, and hence find mates and egg-laying sites and be able to move in the landscape between locations, are scarce. We are using UK Butterfly Monitoring Scheme transect data (supplied by CEH) to understand the complex relationship between abundance and weather.

Climate change will provide new opportunities for some butterfly species in the British Isles and we are also working (with Butterfly Conservation)on a project designed to determine the precise resource and landscape requirements of butterfly species that have been long extinct within the UK, with a view to assessing the viability of re-introduction into the UK under changed climate conditions.

2. Ecological classification of butterflies
Where a species occurs is dependent on resource distribution and there is an expectation that species with similar resource uses should co-occur. Early work with the resident butterfly species of the British Isles used basic attribute data, collected independently of information on where species occur, produced an ecological classification of butterflies. Using Principal Component Analysis we identified a group of ruderal species, a group of species dependent on forest structures, a group of species associated with hot-dry locations and a broad generalist species group.

We tested this ecological classification using Butterfly Monitoring Scheme Transect data (CEH) demonstrating the predictive power of our classification. We are now extending the work to the European butterfly fauna (potentially c. 650 species) and the UK moth fauna. Our approach is important since it can be used to identify species which should have similar responses to environmental changes and thus prove to be a useful predictive tool for conservation management.

3. Functional significance of wing colour and pattern
Butterfly wing colouration and pattern are important for intraspecific communication, predator avoidance and thermoregulation. We use image analysis to quantify butterfly colour and pattern in ecologically relevant wavelength spectra , which includes the UV. We gather information, collected in the field, on butterfly microhabitat use and behaviour in the British Isles, Mediterranean and Alpine regions.

This allows us to associate morphological types with vegetation structures and thermal regimes. We have identified groups of species with particular colour and pattern types which are associated with particular habitat structures for specific activities. This work provides basic information about why fine scale vegetation structure is important for butterflies.

4. Butterflies and climate change
We are predicting the activity of a range of butterfly species under different climate change scenarios. A major constraint on butterfly activity is body temperature, and because of specificity of microhabitat use and physiological and morphological differences between populations the response of individual species to climate change is not likely to be uniform across their ranges.

We are collecting data on the thermal physiology and microhabitat use of a range of butterflies to predict how they will respond to climate change. We use neural networks to predict activity on the basis of weather and body temperature. Work with the common blue (Polyommatus icarus) has revealed that there may be geographic differences in activity in response to climate change. These are related to regional differences of climate shifts and to differences between body temperatures at which different geographic populations commence flight activity. Currently (with CEH) we are investigating the biochemical and genetic background to spatial population differentiation in this species.

With Casper Breuker we are also looking at the roles development and developmental plasticity has in determining the capacity of species to react to climate change. Most of this work is being done with speckled wood butterflies (Pararge aegeria).

5. Defining habitats and population structures
In fragmented landscapes many species have restricted distributions and a major problem for modelling their distributions is in determining where a species can occur and where it may not. Our work demonstrates that all the resources required by all the life-history stages have to be taken into account to define a habitat.

The landscape matrix is rarely empty of resources, and vegetation associations are inadequate for describing insect habitats. In addition, the matrix may play a much greater role in the persistence of species than traditionally envisaged. This theoretical work adds complexity to conservation, but adds arguments as to why the conservation of biodiversity has to move from reserves to the whole landscape matrix.

As part of our engagement with Invertebrate Ecology and Conservation, Tim Shreeve is Editor-in-Chief of Journal of Insect Conservation.

People

  • Dr Tim Shreeve - Research Group Leader
  • Dr Roger Dennis - Visiting Researcher

Funding

  • Litmore Shaw Nature Trust
  • NERC (Studentship)
  • The British Ecological Society

  • The Leverhulme Trust

Collaborations

  • Butterfly Conservation Society
  • Catholic University of Louvain, (UCL)
  • Centre for Ecology and Hydrology
  • Centre for Environmental Research - UFZ
  • Natural England
  • Stockholm University
  • University of South Bohemia

Publications

Dr Tim Shreeve