INTRODUCTION

Genetic variation^[1] is a provision for species to have successfully met the challenges of the past and for them to survive and reproduce under current environmental conditions. Conservation of genetic variation is a necessary precondition for the future evolution and adaptability of local populations and of the entire species (see e.g. Newman and Pilson 1997). Thus, conservation of genetic variation is a necessary element in the maintenance of all other levels of biological diversity that we value for their existence and utility. However, genetic variation is difficult to measure directly and is often cryptic in its effects on population and ecosystem dynamics. Hence its loss is easy to ignore - until it is too late to restore - and this can threaten the capacity of species and ecosystems to adapt to changing environments. Genetic erosion ultimately induces species extinctions and ecosystem loss, and eliminates the possibility of using genetic variation for ecological restoration and economic gain.

To avoid extinctions and to maintain or enhance the levels of genetic variation and its distribution among individuals, populations, and species, requires conserving or managing the dynamic forces of evolution. These include mutation, selection, drift and migration, as mediated through the mating system, i.e. the pattern by which individuals mate with each other, including inbreeding and outcrossing. These forces are not entirely independent of ecological factors, but genetic dynamics are not identical with ecosystem dynamics and require separate consideration. Furthermore, these genetic forces are also not entirely independent in their effects on each other and the patterns of genetic variation found in any one species are the result of their joint effects. Nevertheless, these forces can be separated as factors, can be measured, and therefore can be useful for understanding and estimating the dynamics of change. We assert no priority for genetic versus ecological forces or measures, but confirm their differences and the necessity to estimate different threats and influences. Practical applications of indicators may require that one serve as a surrogate for the other but they should not be confused by forest managers as being identical.

Criteria and indicators are tools which form part of a four-level hierarchy of information and knowledge (see Annex 1), from highly detailed, but narrowly specific information represented by “verifiers” to generic, but widely applicable knowledge represented by “principles”. Forming the middle two layers of this hierarchy, criteria and indicators are most useful to conceptualize, evaluate, monitor and support sustainable forest management (Annex 2). They may be identified and applied at various levels: global, regional, (and eco-regional) national, and local which, in the context of forest sustainability, would normally be the forest management unit level. Assessment (or evaluation) of sustainable forest management is the process by which information about forest management is collected with a view to establishing, within a defined framework of expectations, the current status and probable future direction of the interactions between human beings and forests, using certain criteria and indicators (Prabhu et al. 1996). Assessment can thus be seen as an important step in a process that Munda (1993) describes as cycling through initial disorientation, reorientation or choice, towards a solution or decision.

Criteria and indicators, which are neutral assessment tools for monitoring trends, provide a means to measure, assess, monitor and demonstrate progress towards achieving the sustainability of forests in a given country or in a specified forest area, over a period of time. By contrast certification is a means to certify the achievement of certain, pre-defined standards of forest management in a given forest area, at a given point in time, agreed upon between producers and consumers. However, it may be possible to draw on criteria and indicators when developing standards or guidelines for performance at the management unit level, for forest certification, as has been done in many cases (see Annex 2 for relationship between the concepts).

Probable users of criteria and indicators will include government institutions trying to design more sustainable policies pertaining to forestry and other related sectors, forest owners, or donors wanting to evaluate the sustainability of the activities undertaken in various natural resource management projects. Potentially the most relevant users would be those forest managers who want to improve the sustainability of their management at the forest management unit level through a process of continuous monitoring of the impacts of management interventions and modification of practices in response to those impacts - that is, applying the principles of “adaptive management”.

The application of criteria and indicators for sustainable forest management is very attractive because it provides for continuing assessment and adaptation, rather than periodic assessment at which time the damage may have been already done. However, if criteria and indicators are to be applied by untrained or semi-trained teams in forest management units (FMU), the assessment process needs to be straight-forward and easily interpretable. These requirements have guided our design and assessment of criteria and indicators focusing on genetic conservation.

When criteria and indicators at the forest management unit level are applied and made operational, they would ideally be incorporated into standard FMU management activities, such as inventory. Any additional effort would be limited to, perhaps, adding a small team of 3-5 people, over a period of 1-2 weeks. This is because criteria and indicators assessment will clearly be a costly exercise, and larger teams or longer periods will make the process too costly to be acceptable to those who bear the costs, be it governments, non-governmental organizations or industry. In the time available, these teams will need to assess indicators related to all criteria and thus to all aspects of sustainability: biophysical (environmental), social, and economic. These considerations dictate that the most important characteristic of an effective indicator or verifier will be its relevance, and the practicality of assessment in a short period. The need for practicality is a serious constraint for the assessment of “conservation”, which implies a need to consider temporal dynamics.

It is not anticipated that criteria and indicators will be applied to situations where land-use change is planned, for example on areas scheduled for conversion to agriculture urban areas, or industrial/infrastructure development, or establishment of non-native forest tree plantations. The impacts of such land-use changes on native genetic resources fall outside the scope of the present paper. Furthermore, it is noted that it may not be necessary to include conservation of genetic variation as a major goal for every FMU. Various authors (e.g. Seip 1996), and documentation in the on-going criteria and indicators processes, stress that different forest units may be managed for different purposes, with varying emphasis on conservation, production, protection, recreation, etc..

Criteria and indicators are at times developed within a conceptual framework which recognizes “pressure”, “state”, and “response” indicators. In a complementary process to the present one, aimed at identifying criteria and indicators of biodiversity conservation, Stork et al. (1997) showed the equivalence of pressure-state-response indicators to different components of a system involving human interventions, mediating processes, processes that conserve biological diversity, and the response of biological diversity itself (Figure 1). Brown et al. (1997) pointed out that pressure, state, and process (equivalent to response) indicators have different information contents. For example, assessing verifiers of the mating process is potentially very valuable, but it is also rather difficult and expensive. Verifiers of population size may be used as surrogates of mating, but its information content is less. Conversely, individual genetic variation provides more information on the actual response to mating, but the effects of other developmental processes are confounded in verifiers of individual variation. Therefore, the choice of appropriate indicators and verifiers is always going to be a trade-off between information content, scale of monitoring, and costs.

We are encouraged in our approach by the report of the CIFOR project on testing criteria and indicators for sustainable forest management (Prabhu et al. 1996), which documents the lack of criteria and indicators for assessing biological diversity at all levels of the biotic hierarchy. It suggests that a “tool box approach” would have the highest utility for potential users. The term “tool box” reflects the fact that prescriptive approaches to assess sustainability for such complex systems as forests, which are used for many diverse purposes, would be doomed to failure. Rather, providing forest managers with a tool box allows them to select and apply the most appropriate tools for their specific needs.

It is important to assess genetic variation in order to determine sustainability because genetic variation and diversity provide the basis for adaptation to changing conditions. The loss of genetic variation within a species leaves that species vulnerable to local extinction. For the same reason, genetic variation and diversity are far better indicators of ecosystem stress than measures related to population sizes, or such-like. For example, if individuals within a species are obliged to inbreed at a high rate, due to changes in the environment, reproductive success may not initially be affected, so that population levels may remain constant while genetic variation is being eroded. By the time that reduced reproductive success results in detectable decreases in population size, the damage may have been done at the genetic level, and the species may already be doomed to extinction. However, as genes are not easily measurable, and their individual effects often are subtle, it is an extremely difficult task to design effective and practical ways to measure genetic diversity. The various processes which support the establishment of systems of national and regional level criteria and indicators around the world have to date not succeeded in defining realistic indicators for genetic diversity (see Annex 3).

Figure 1. Conceptual model of the relationships between anthropogenic interventions under different forest management regimes, mediating processes, ecological processes which shape biodiversity, and biodiversity. Indicators that are relevant to the left-hand side of the figure are “Pressure” indicators, while those on the right are “State” or “Response” indicators, which are better surrogates for biological diversity than for genetic variation.

Adapted from Stork et al. (1997).

In the present paper, we focus mainly on tree species and variation in them. Tree species provide the basic structure in forests within which other organisms find suitable habitats. However, disruptions to genetic processes may well occur in other forest-related organisms even when the trees are not adversely affected. Therefore, a comprehensive assessment of conservation of genetic variation must not exclude other groups of species, such as forest shrubs and herbs, vertebrates and invertebrates.