Monitoring

Monitoring method

Periodic collection of demographic data is perhaps the most commonly used method for monitoring plant populations. Monitoring using ecological data identifies changes in the physical environment that shape the target CWR population and affect the dynamics and composition of the living communities with which it is associated.

Overall, a combined approach using demographic, ecological and anthropogenic parameters is desirable. This way not only the target species is monitored directly, but also the biotic and abiotic conditions and the human activities that might contribute to changes in population dynamics are examined and taken into account.

Genetic diversity monitoring programmes may also be carried out. However, given that this type of monitoring requires staff with specific skills, specialized equipment and/or higher financial resources, it may be less likely to implement unless there is a need to answer a specific question that requires such data.

Physical environment

Parameters like climatic conditions (temperature, rainfall, humidity) or soil nutrient content need regular monitoring to assess their impact on the population dynamics. A periodic assessment of these variables can be useful to identify any changes in the physical environment of the species, such as land use or stochastic events that can lead to either population reduction or increase.

Use temperature and moisture sensors to obtain a daily record of these variables in the site, and a pluviometer to record rainfall. Consider using devices to store all data collected. Another possibility is to collect data from nearby weather stations. Monitoring of soil nutrients will require periodic sampling and chemical analysis by a competent laboratory. The need and periodicity of such tests will have to be assessed by the genetic reserve manager. Other variables that are not likely to change, such as topography, soil structure and texture do not require periodic monitoring.

Use this data sheet to collect field data when monitoring the physical environment.

Biotic interactions

Most CWR species rely on pollinators and seed dispersers to maintain the gene flow within and between populations. Assess regularly the presence of flower visitors and seed dispersers, their relative abundance and frequency of visits, as well as the target species' phenology.

Similary, regularly monitor the presence of pests and pathogens in the target CWR, and changes in frequency and composition of the plant community.

All this information is of utmost importance to be able to associate changes in population size or genetic diversity with possible underlying causes. It will be very useful for the management of the target CWR populations.

The periodicity of the biotic interactions monitoring will depend on the conservation status of the target CWR population. For healthy CWR populations with stable demographic trends, one monitoring event every six years may be enough, while endangered CWR populations may need surveys on biotic interactions every year.

Use this data sheet to periodically monitor the biotic interactions.

Anthropogenic factors

Include in the monitoring programme threat assessments of the CWR populations. It will allow you to identify the levels of endangerment of the different species and to assess the effectiveness of conservation measures in place.

Monitor accidental introductions of alien invasive species, deforestation or active logging of habitats, pollution, climate change and other human-induced disturbances to determine their impacts on the population size and interactions at the local scale.

The periodicity of the threat assessments will depend on the degree of human intervention in the area where the genetic reserve is located, and changes in ownership, occupation, management and land use. Accordingly, it may vary from yearly assessments to one every six years.

Use this data sheet to gather information on the threats to the target CWR populations (based on the IUCN Threats Classification Scheme)

Demographic monitoring of target CWR populations

Systematically collect data over time to detect changes in population size, age/size structure, trends and to estimate extinction risk. Therefore, to assess the population's viability.

The monitoring of CWR populations may indicate demographically unstable populations, hence, a need for specific conservation measures. Assessing the structure of the population and its size requires the stratified sampling of a number of seedlings, juveniles and adults, while population trends can be assessed through data collection of survival, growth and fertility of concerned plants in the target CWR population.

The simplest way of conducting the demographic monitoring is by periodically following the same procedures that were initially defined to characterize both the population size and structure.

There are several ways of developing a population viability analysis for the target population. Morris and Doak (2002) provide a good account and procedure details about them.

Genetic monitoring of target CWR populations

Analysis and assessment of the genetic diversity within CWR populations is a crucial step to understand the dynamics of the populations and their adaptive potential.

Genetic monitoring is important to understand the:

• genetic diversity in populations
• degree of inbreeding in the target population
• effective size of the population
• population structure for a target CWR species
• rate of gene flow
• minimum viable population
• allelic diversity for a particular gene responsible for a given phenotype.

Neutral markers, such as microsatellites or more recently SNPs corresponding to non-transcriptional regions of the genome are the most appropriate for estimating genetic diversity, inbreeding, population structure and gene flow, whereas the determination of allelic diversity for particular genes will ideally involve the complete sequencing of that gene.

The economic resources available and the collaboration with research laboratories with genetic or genomic capacities will determine the extent of the genetic studies in the genetic reserve. Ideally, in addition to an initial screening of the genetic diversity of the population it would be advisable to repeat the genetic characterization periodically to monitor the genetic dynamics of the population. The periodicity of the genetic survey will greatly depend on the life history characteristics of the target species. Thus, long-lived species with high generation times will require fewer surveys. On the contrary, for annual species, it would be advisable to conduct a genetic monitoring every six years (Goldringer et al., 2006).