Authors: Dr Andrew Jones and Sue Everett, for Flora locale
Conserving genetic diversity in woody species and woodland ground flora
encourage appropriate research to fill gaps in knowledge about native plant genetics, with priority to gathering data and information needed to inform the development of policy and practical action (relevant to implement the UK Biodiversity Action Plan).
This document aims to identify these priorities from the point of view of Flora locale and its interests, which are:
to promote and advance the conservation and enhancement of native wild plants and their associated biodiversity, with particular regard to creative conservation, ecological restoration and the conservation of genetic diversity.
The following explanatory text is drawn from the "rationale" developed for Session 1 of the workshop held in 1999 on research needs for "Introductions, Translocations and Genetic Conservation". Please refer to Annex 1 for the report from this workshop.
The emphasis of many habitat BAPs, the agri-environment programme and the UK forestry strategy is now upon ecological restoration, involving large scale plantings and sowings of native plants to "re-create" habitats, reduce habitat fragmentation and generally enhance the biodiversity value of the wider countryside. Current restoration activity (including native woodland replanting and establishment) involves:
the introduction and establishment of non-native genotypes, varieties and cultivars of native species (e.g. hybrid Sorbus, Common Alder Alnus glutinosa from Hungarian sources cone size in the non-native trees is up to 35% larger than in native trees which may occur close by planted ones, rye-grass cultivars)
the introduction and establishment of non-native species that are related to native species (dogwoods Cornus spp., Spanish Bluebell Hyanthoides hispanica)
translocations of native species (e.g. Wild Thyme from Scotland planted on arable reversion grassland in southern England).
At the same time, biotechnology research is resulting in the development of modified varieties of native plants, as well as relatives of native plants that might be widely established in the countryside for agriculture, forestry or amenity purposes. Alongside this, traditional plant breeding has, over the past few hundred years resulted in the selection and widespread introduction of agricultural and horticultural cultivars of many common-place natives, such as clovers and grasses.
As the popularity of organic farming increases, there is already evidence of increasing interest in the utilisation of other native species (e.g. Lotus corniculatus, Trifolium pratense) in agriculture, with the probability that large quantities of DUS (Distinct, Uniform and Stable) registered cultivars will be utilised. There is also increasing interest in utilisation of wild species for biomass production with the implications that large tracts of land could be planted with monocultures of cultivars that have living wild relatives existing within the same region.
Trees exhibiting certain external and morphological characters (e.g. "phenotypically superior characters" such as straight tree trunks and lack of epicormic growth) have been increasingly "selected" for forestry and landscape purposes. In recent years these have been widely planted in hedgerows, ancient woodlands and in new native woodlands, in preference to "wild" examples. Trees and shrubs of non-native (often Central or Eastern European) origin, are all too often introduced in places close to where native populations of the same species occur (e.g. early-budding, mildew-susceptible and thornless Common Hawthorn of continental European origin used in hedge planting) Jones, A.T. & Hayes, M.J. & Sackville-Hamilton, R. The effects of provenance on the performance of Crataegus monogyna (Hawthorn) in hedgerows. J.Appl.Ecol. In press. A recent study of Alder, showed that trees of non-British (probably Hungarian) origin had been established close to wild populations growing in a European Special Area of Conservation, and that the introduced trees were superficially very different.
Tree selection is now being expanded, using improved techniques based on traditional plant breeding as well as genetic modification, to produce new varieties for timber production and horticultural use. Knowledge of the actual or likely impacts (which could be beneficial, neutral or detrimental) of all these activities on the genetic diversity represented within native plant species (especially those which are key components of fragmented BAP habitats, such as those represented by seminatural grasslands, wetlands and ancient woodlands) is extremely poor. Also the knock on effects or benefits to associated fauna are mostly unknown.
Compared to the issue of genetic modification of species, the introduction of hybrids, cultivars and non-native planting stock has received little attention to date, and no environmental risk assessment protocols or regulation concerning protection of the environment from such "releases" exist. Neither is this issue considered within existing R & D into utilisation of "selected" or "modified" native plants (e.g. in agriculture or forestry). The strategic research needs are, however, likely to be broadly similar.
Identification of research priorities
Many of the research priorities we have identified have relevance and application to countries outside the UK. Some could therefore benefit from collaborative approach to this research, and an information collation exercise, with respect to other countries of the European Union, the United States and Australia (the latter two countries being ones where there is already significant relevant research activity as well as practical action).
In the context of the UK, we have identified two groups of habitats where we consider research is a particular priority: grasslands and woodlands/hedgerows/scrub. This is because the majority of restoration effort that is currently involving plant introductions is for these habitats or their associated species.
However, the research objectives we have identified for these habitats could also be applied to others if resources permit, although for some other habitats (e.g. heathland and moorland) restoration is tending to follow the precautionary principle with respect to plant introductions, concentrating on natural regeneration (habitat management) or introducing seed from similar areas in the locality.
Our proposals should be read in conjunction with the Forestry Commission document (Genetic Variation and Conservation of British Native Trees and Shrubs: Current Knowledge and Policy Implications) and the report of the 1999 workshop (reproduced at Annex 1). The former report is available from the Forestry Commission or the Stationery Office.
1. Local/regional genetic distinctiveness and patterns in variation for selectively neutral genes/micro satellites - to survey regional genetic differentiation in common grassland plant species including dominants and key community components.2. Grassland genetic diversity - to measure genetic variation in plant populations for some common grassland species in relation to grassland management, area and isolation.3. Genetic/phenotypic flexibility - to measure variation in life history in response to changes in grassland management and climate change.4. To measure the importance of genetic variation in new habitats.
5. Seed harvesting and introduction strategy - optimising the transfer of genetic variation from donor to recipient habitat
All of these threats require investigation in terms of their implications for grassland conservation and it is argued that more emphasis should be urgently given to studies of grassland plant species genetic variation, as a cornerstone of grassland habitat health. Research has been devoted to loss and fragmentation of habitat in terms of metapopulation studies but the focus in the UK has mainly been on animal species. Climate studies have focused on whole community response to warming and drought and not studied the detailed behaviour of species at a population level.
There has been no work on the significance of grassland restoration, which is the main thrust of the UK Habitat Action Plan for lowland grasslands, for the conservation of plant species genetic variation. There is a need to urgently evaluate the remaining genetic diversity of both rare and common plant species, including habitat building block species and its significance in relation to continued survival of wildflower species in increasingly unpredictable grassland habitat. This information is important in refining precautionary policy on species sourcing and movement in terms of habitat restoration.
With the exception of studies on the evolutionary history of a few tree species (oak, Scots pine), most studies have focused on rare species, including those that have shown alarming decline and those with ancient, restricted distribution.
Scant work has been carried out on the regional and local patterns of selectively neutral genetic variation in common ecological building block species and associated species. It is important for the conservation of our flora that we are aware of the detailed subspecific taxonomic status for selected species and the distribution of these taxons across the UK. Such patterning constitutes a record of the history and evolution of the British Flora and may also encompass major axes of adaptive variation within species. This information can be used to refine our judgement in terms of sourcing for habitat restoration.
It is important to screen for levels of genetic variation within the populations of key species in remaining grassland in relation to the numerous threats they face. Habitat fragmentation, climate change and environmental quality are key threats, but increasingly poor grassland management caused through livestock shortages may reduce population size and impoverish gene-pools. Other risks associated with intensive farming (e.g. introduction of GMOs and selectively bred plants) may reduce weed diversity causing a knock-on loss in pollinator diversity and abundance. Monitoring of levels of population genetic variation (measured as heterozygosity, proportion of polymorphic loci) within species for key grassland habitats should be a priority.
Genetic/ phenotypic flexibility - to measure variation in life history in response to changes in grassland management and climate change
Seed harvesting and introduction strategy - optimising the transfer of genetic variation from donor to recipient habitat.
The science of habitat restoration has not been fully developed, especially in terms of the sampling and transfer of genetic variation from donor to recipient habitats. More information would allow us to adopt best practice methodologies in reconstructing habitats. The extent to which we can generalise in our methodology based on breeding system, life history strategy and habitat occupancy is unclear and more information might provide us with best-fit options. Questions we may ask, with the assumption that we should collect from local sources include:
How locally do we collect for a habitat type or individual species?
How do we sample (by hand-collection, brush harvesters, hay bales, green hay) variation at donor sites in terms of pattern and scale in order to maximise carry over to recipient sites?
Do we repeat sampling during each growing season to reinforce the richness of genetic variation?
What are the impacts of seed harvesting on population processes and genetic variation at the donor site?
- What approaches and techniques are most likely to deliver biodiversity objectives for successful grassland restoration and conservation of plant genetic diversity (e.g. Is inoculation of recipient sites that have already been reverted to grassland, or managed as naturally-regenerated set-aside, more efficient in terms of resources and results than agricultural scale sowing of expensive seed on to bare land?; Is repeat sowing a useful and successful technique to ensure sustainable populations are established?); what are their comparative costs and timescales needed; what changes are needed to current policy to implement the necessary changes?
What is the maximum number of generations that a crop can be harvested before shifts in genetic variation take place?
Are there shifts in life history strategy within species in the process of wildflower seed production?
If a species is to be grown as a crop, what rules should there be for separating cops that represent different origins for a single species? Should plants of different origins be grown only in their regions of origin?
The Forestry Commission recently issued a consultation paper on Genetic Variation and Conservation of British Native Trees and Shrubs (Ennos et al., 2000) and the recommendations put forward in this document should be pursued.
There is also increasing interest in "holistic" woodland creation. Until now, new woodland plantings have been confined to planting trees and shrubs, but techniques for introducing ground flora have been recently developed. Woodland ground flora species tend to be slow colonisers and many populations are isolated as a result of habitat fragmentation. Within and between individual native woods there may well be considerable genetic variation within a single species. Over a larger area, such as an English Natural Area, or a region, there could be significant genetic variation. There is, however, a major fear that the interest in woodland ground flora introductions will fail to recognise these differences and that plant users will buy and use "off-the-shelf" seed and plants obtained commercially and of unknown origin. This "quick-fix" approach is what already happens with most habitat creation - designed to suit institutional budget cycles and other imperatives which have very little to do with best practice for biodiversity.
Research is clearly needed to inform future policies for such introductions and so as to ensure that in the desire to re-create "native" plant communities, such reintroductions are carried out in accordance to best practice and in the interest of genetic as well as habitat conservation.
A major product of this research would be guidance on plant sourcing that could be used by restoration ecologists and others involved in procuring and using native flora for large-scale habitat creation projects. Until such research data is forthcoming, Flora locale recommends the precautionary principle for plant sourcing, i.e. sourcing plants from the local area, particularly within or close to ecologically sensitive zones, contract-collect-grow or natural regeneration (where feasible). Details of Flora locale's guidance on plant sourcing can be found here
The priorities identified below are both for woody and non-woody woodland and hedgerow species.
1. Local/regional genetic distinctiveness and patterns in variation for selectively neutral genes/microsatellites - to survey regional genetic differentiation in woody species and associated ground flora
2. Genetic diversity in woodland and hedgerow species: to measure genetic variation in plant populations for some common species in relation to habitat management, area and isolation.
3. Seed and genet harvesting and introduction strategy: optimising the transfer of genetic variation from donor to recipient habitat.
Local/regional genetic distinctiveness and patterns in variation for selectively neutral genes/microsatellites: to survey regional genetic differentiation in woody species and associated ground flora
Some of the woody species of woodlands such as Wild Service-tree (Sorbus torminalis) and Small-leaved Lime (Tilia cordata) are comparable with ground flora species in their poor reproduction and dispersal and increasing isolation and would be expected to show high levels of local/regional differentiation calling for genetic research and cautions reintroduction programmes.
Genetic diversity in woodland and hedgerow species: to measure genetic variation in plant populations for some common species in relation to habitat management, area and isolation
Seed and genet harvesting and introduction strategy: optimising the transfer of genetic variation from donor to recipient habitat
2. Identification of biodiversity risk posed by plants that are already widely used or proposed for widescale introduction
Development of risk assessment protocols for application in R & D for new agricultural crops (particularly forestry, fodder and biomass crops).
Protocols for such risk assessment must be produced, so that they can then be adopted within relevant R & D. Flora locale considers that it is currently a significant anomaly that such protocols have been introduced for proposals to introduce Genetically Modified (GM) species, but that they have not been applied to the development of plants bred by "traditional" crop breeding techniques. Clearly this area of risk assessment needs to be addressed not only within the UK but at EU and international level as well.
Flora locale requests that the DETR asks ACRE to consider how this issue, and the research needed to identify existing and imminent risks (see Objective 2 below) might be addressed, initially in a UK context.
We also recommend that appropriate risk assessment protocols are developed that can be applied to any activity, particularly those associated with agriculture or forestry, which are likely to involve the large-scale introduction of a non-native plant species into the countryside, whether related to a native species or not. Recent examples of introductions that should have been subject to prior risk assessment include Miscanthus (a biomass crop), Phacelia (a set-aside cover-crop) and general "game-cover" crops - which can consist of a variety of different exotic and native species introduced from seed of unknown origin.
Investigations should be carried out to assess and catalogue the impacts of current native species introductions on our native flora. Initially, research should focus on grasses (including rye-grass, fescues and bents), clovers, willow clones (already beginning to be introduced for biomass crops), and a selection of timber species including the newly developed "Wildstar" cherry. Risk assessment should consider both direct and indirect biodiversity risks associated with such introductions.
(Extracts from the report Setting the agenda for biodiversity research: Introductions, translocation and genetic conservation. Report of a workshop held on 18 November 1999). Click here to go to the full report)
THEME 1: Genetic conservation, translocations and the introduction of exotic, artificially selected or modified varieties. Focus on plants used in agriculture (including agri-environment), ecological restoration, landscape and forestry.
The rationale has been included in part 1 of the main report.
1.2 Key Issues
Four key issues were identified under Theme 1:
2. Understanding existing patterns and extent of genetic variation
3. Impacts of introductions and policy
4. Developing strategies for genetic conservation
The Chairman expressed a view that participants in Session 1 had considered that all the topics they had identified were important. He emphasised that the research programme needed to be progressed at a variety of levels and that much of the work identified would need to be done in parallel, or sequentially (an experience mirrored by the other two sessions, which did not attempt to prioritise either Key Issues or Topics).
The session considered some of the topics in further detail, identifying some:
specific objectives and information needs
potential users and funders of research
organisations which hold relevant expertise.
Key Issue 1: Defining objectives of genetic biodiversity and specifically what Biodiversity Action Plans should include
Topic 1.1: Agree concepts and develop stakeholders' awareness
Consistent use of terms
Agreement on a set of biodiversity objectives for genetic conservation
Improving awareness of the issues (via a revised Biodiversity Action Plan) See Planting with wildlife in mind: the supply and use of native flora for projects in the town or countryside: A cross cutting action plan for UK biodiversity (Flora locale, 2001)
Species range issues (edge of range, etc.)
What other countries have attempted to set genetic biodiversity guidelines?
Topic 1.2: Develop policy and guidelines for implementation
Note: Delivery requires completion of topic 1.1 and 2.2.
Key Issue 2: Understanding existing patterns and extent of genetic variation
An example is to distinguish between genetic variation that is selectively neutral (i.e. that might be useful in helping to distinguish patters of genetic structure within and between populations) and that which is subject to selective pressures (that will potentially have a large effect on survival potential and competitive ability)
Topic 2.1: Data basing/networking of known variability in native species and identifying groups
An understanding of the range of variation in native species is needed before assessments can be made of the impacts of introduced genes. Given that knowledge, it may be possible to divide species, depending on factors of their biology and ecology, into groups that are more or less vulnerable to genetic change. A baseline of existing information will help define priorities for, and direct, future research (Topic 2.2). This necessitates:
Collating published and unpublished data
Making data widely available and accessible.
Topic 2.2: Define research priorities
seeking to identify generic categories/functional groups
selecting model species.
Specific information needs are:
a database (see topic 2.1)
historical information (i.e. on selective breeding)
life history parameters.
International: lots of reviews are available via various fora.
Topic 2.3: Measurement of genetic variation (new research)
Identifying variation in relation to population, region, Esc
Separation of neutral (structure) and adaptive variation
Adoption of a comparative approach
Standardised sampling of analytical methods and procedures.
Nature of the research: Science research project
Key Issue 3: Impacts of introductions and policy
The major potential impacts on within-species genetic diversity require different approaches, which involve:
Identifying effects of habitat fragmentation (this links to the DETR Biodiversity Research Support Project workshop 4
Landscape Ecology, Habitat Fragmentation and Land Use Change Scenarios])
Identifying the consequences of different selection pressures.
Nature of the research need: Science research project
Topic 3.2: Assessing the impact of introductions and translocations on non-target species
of hybridisation and introgression
on dependent/specialist herbivores and other species
of changed competitive interactions/disease and other pathogens
on ecosystem function.
Topic 3.3: Longer-term changes in introduced species (2)
The natural processes of evolutionary change mean that there may be long term adaptive change in key species (e.g. in relation to climate change). Such long term change can only be assessed by monitoring genetic change and phenotypic indicators.
Key Issue 4: Developing strategies for genetic conservation
Topic 4.1: Developing national strategies for genetic conservation
Revision of Issue 1
Selection of genotypes for introduction, reintroduction and translocation
Develop policies for ex-situ conservation
Identify the role of nature reserves and in situ genetic resource conservation
Identify the role of improved stock (i.e. selectively bred material) in restoration, etc.
Topic 4.2: Review and revise the regulatory framework
Review the impact of current regulations (e.g. the Seed Regulations) and policies (e.g. for agri-environment schemes)
Develop strategies and guidelines for the supply of plants.
Policies for ecological restoration (e.g. wildlife corridors, habitat networks).
Practitioners in the ecology, landscape/amenity & forestry sectors: people who use plants for agriculture, ecological restoration, landscaping, forestry
Policy makers and project funders: organisations who fund ecological restoration and forestry projects and make sectoral policies (e.g. MAFF, Forestry Commission, Heritage Lottery Fund, Entrust)
Research and development including people and organisations who develop novel plants by selective breeding
Research funders: government and industry bodies which fund relevant R & D
Horticultural & landscape industry
Government bodies with a regulatory function (e.g. DETR, MAFF).
Organisations currently funding research include: NERC, DETR, MAFF, FC, EC, Conservation Agencies and BAP champions.
Common issues identified across all three themes considered in the workshop
1. Understanding the biology and ecology of species and their function in habitats and ecosystems
Together with the introduced and invasive species group (Theme 3) it was recognised that knowledge on the biology and ecology of species is fundamentally important to identify biodiversity impacts of introductions and translocations and for risk assessment.
Other common research topics under this heading include the identification and understanding of: genetics, physiology, behaviour, population dynamics, life history & reproduction (of individual species), distribution, habitat use and preferences (including historical information) patterns and rates of gene flow between introduced or translocated species and their native relatives relationships with other, non-target species (e.g. dependent herbivores) effects on ecological processes (e.g. changed competitive interactions, parasite loading, pathogen dynamics) that in turn may alter the population ecology and dynamics of native species effects on ecosystem function (e.g. large scale habitat modification).
2. Review and collation of information and data
A database on information about introduced species was identified as a high priority, and there was a strong feeling that a focal point needs to be identified to co-ordinate and act as a lead on this work.
The identification of focal points and the collation of data and information were identified as being important to:
facilitate information exchange
encourage collaboration among researchers
promote co-ordination over research
encourage research projects that are needed to fill information gaps
assist with international collaboration (e.g. IUCN initiatives on introduced and invasive species)
deliver more effective information to enable policy-makers and conservation managers to take appropriate and effective action.
This is needed to select species for which new research and study is a priority.
This exercise would need to consider species that might be introduced or translocated in the future, or subject to research and development (i.e. of novel varieties for commercial exploitation), as well as species that had already been introduced or translocated.
4. Prediction, monitoring, impact and risk assessment
Research should identify thresholds whereby change is unacceptable for biodiversity. The identification and understanding of different agents of change is also necessary, to distinguish between changes resulting from natural events (e.g. climate change) and human activities (e.g. artificial stocking). Both direct and indirect impacts need to be considered - an example given by Theme 2 was sea lice infestations of farmed salmon and the use of pesticides to control infestations - and the impact of these on wild salmon populations.
Long-term research is important to monitor and identify temporal changes associated with certain introduced and invasive species, but at present there is very little comparable long-term data. Theme 3 noted examples of introduced species that were once considered as having a significant biodiversity impact but which, after some years, had become well integrated into native habitats and no longer pose a threat.
Data from long-term monitoring was therefore considered important when deciding whether an invasive species should be controlled or eradicated (and how this might be achieved).
5. Biodiversity action: development of tools, strategies and measures
Evaluation and analysis of policy and regulation was identified as a high priority by all three themes. Responsibility for setting policies and regulations are currently dispersed among different sectors (e.g. agriculture, horticulture, forestry, wildlife) and it was felt that the current suite of measures may not best serve, and sometimes conflicts with, biodiversity conservation needs. Theme 1 proposed that biodiversity impact/risk assessment of policy should be considered within any reviews or analysis, and when new policies are under development.
6. Socio-economic research
Such evaluations need to consider any costs that may be associated with
loss of biodiversity and the consequent loss of benefits and services biodiversity provides (e.g. damage caused to inland salmonid fisheries as a result of fishfarm escapes)
the costs to industry arising from introduced species (e.g. cost of dealing with power station water intakes clogged up with introduced bivalves).
Trade and economic exploitation of species are principle purposes and vectors for introductions and translocations - necessitating socio-economic considerations to be addressed by research and conservation action.
Public perception and attitudes were considered important by Theme 3, especially when considering whether an introduced invasive species should be controlled or eradicated. There is wide range of perceptions about introduced species among the public, by science researchers and ecologists. New communities of species, many of them introduced and exotic, have become established in urban areas - and are viewed as being an important part of the urban landscape. Some research underway illustrates that communities of exotic species can be well adapted to the climate and geography of urban areas and this is spawning new areas of research into the ecology of urban environments.
Perceptions and attitudes, either in relation to eradicating certain invasive species or keeping them because they appeared to be beneficial to the urban landscape, are often not based on scientifically-based knowledge (e.g. the degree of threat posed to biodiversity). The importance of developing a scientific rationale for making decisions about species management and control was therefore emphasised. Knowledge of public perceptions and attitudes would need to feed into any subsequent control/eradication strategies that may be developed. A research topic identified by Theme 3 was a decision support system - this would need to take into account socio-economic considerations.
Knowledge of public perceptions and attitudes will also be fundamental to certain research identified by Theme 1 and 2 (and using the results of research to develop policies and other measures). The recent problems experienced by experimental research (field trials) and releases of Genetically Modified Organisms illustrates how important such perceptions and attitudes can be not only in delivering policy but in successful execution of research.