| Foresty Commission programme manager: | Sallie Bailey |
| Research contact and location: | Joan Cottrell Ecology Division Forest Research and external partners |
Biodiversity is the product of variation at the level of the population, species and ecosystem and policy aimed at conservation of biodiversity must address variation at each of these levels. This programme largely deals with variation at the sub-species level and concentrates on the assessment of variation within and between populations of a given tree or shrub species. The aim of this programme is to advance scientific understanding of the current patterns of genetic variation amongst native tree and shrub species in Great Britain, and to assess the influence of past, current and future management practices upon genetic variation. As a result, management recommendations for conserving genetic diversity and future adaptability will be produced.
There will be a strong focus on determining whether the origins of planting stock in native woodlands affect their ability to adapt to local conditions in future. Linkage to the Landscape ecology programme will be important. There will also be close linkage to tree breeding work for native species the programme Improvement of broadleaved species, so that the implications for genetic conservation of the use of improved and selected stock can be evaluated together in the programme Improvement of broadleaved species.
The establishment and assessment of nursery and field provenance experiments make up the core of the programme and these examine adaptive traits of several native trees starting with birch, ash and rowan. This is being complemented by allied work carried out collaboratively by East Malling Research (formerly Horticultural Research Institute) and Forest Research, which is co-funded by Defra and the Forestry Commission. Alongside the provenance research is a programme of work based on molecular markers, which will tell us more about population history (including post-glacial migration routes), population structure, mating characteristics, and gene flow between populations. This information is being used to advise on management strategies for native tree species.
An early step has been to survey, identify and establish a database of autochthonous (self-seeded of local origin) native tree populations in England to add to those already completed for Scotland and Wales.
Technical advice on the effect of the Forest Reproductive Material Regulations on all aspects of genetic conservation policy is covered under this programme.
Commissioned reports
Date: November 2005
Title: Restoration of wooded landscapes – Informing assumptions with microsatellite technology
Author: Andrew Lowe
Full report: PDF
Summary:
Microsatellites are a very powerful molecular marker tool. They can and have been used extensively to understand the contemporary population dynamics and connectivity of individuals within different landscape settings, and are arguably the best molecular marker currently available for such purposes. The literature on conservation genetics has ballooned since the introduction of these markers. Numerous studies now exist that examine the dynamics of genetic diversity across changing landscapes, inc luding those subject to fragmentation. Using specialized statistical methods and variation within nuclear and organelle genomes, microsatellites also offer insights into historical colonization processes and population evolutionary history, which are informative for making predictions of contemporary and future colonisation dynamics and range shifts, e.g. due to landscape changes and climate change.
One of the strengths of a PCR-based marker like microsatellites is that it can be used with very small quantities of living and/or dead tissue of the study organism. Thus it is possible to use historically collected material (e.g. from herbaria or museums), and has added a temporal context to several studies. Whilst not a universal marker (one which can be applied to any organism), microsatellites can be developed for almost any species with even modest research budgets. Microsatellites have been isolated for a range of species, including, plants, mammals, birds, insects and fungi. Whilst microsatellites do not give the researcher direct access to community or habitat assessments of species richness, by applying a range of recently developed statistical methods, they inform on the processes of propagule, individual and population movement and dynamics for specific species.
Microsatellites have been applied to an increasing number of studies of European flora and fauna. This review documents a representative sample of this research to examine; historical colonization, contemporary gene flow dynamics and the impacts and restoration of fragmented landscapes. This review finds that microsatellites are suitable for assessing each of these parameters and give detailed information on an individual species response. A key concern of many surveyed studies is that genetic diversity and connectivity processes are impacted by fragmentation. This is evident across taxonomic groups. Strategies to improve habitat connectivity, such as corridors and stepping stones, are demonstrated to improve patch connectivity and increase gene tic diversity. However the literature also indicated that connected remnant networks of this type were not as effective at maintaining diversity as large blocks of continuous habitat.
Three key and related issues are prioritized for future research development:
- Undertake genetic studies for a range of species (flora and fauna with a range of life history characteristics) within heterogeneous fragmented landscapes containing different patch sizes, isolations and histories. Studies should either be done within a single location or aim to integrate studies that control for scale and habitat quality.
- Improved evaluation of natural dispersal/recruitment processes and corridors/stepping stones as methods to maintain diversity and rehabilitate habitats.
- Improved understanding of genetic diversity and differentiation of individuals/ populations to be used for reintroduction and rehabilitation. Knowledge is required on the number, proximity and habitat/environmental context of reintroduced individuals to maximize diversity and adaptive potential whilst minimizing genetic erosion.
