Management interventions
Set of actions that should be implemented in order to minimize and/or mitigate any threats on your target populations.
Different potential or existing threats may compromise the viability of target CWR populations in the genetic reserve. Once all threats are identified and scored at the time the genetic reserve is established or because of a periodical monitoring survey, proper management interventions must be implemented to minimize and/or mitigate their effects.
Management interventions aimed at mitigating adverse human interactions, may involve changes to the physical environment, biotic interactions and target CWR population(s) to enhance their self-sustainability.
Where to focus on
Depending on the nature and impacts of the threat, management interventions may be directed at different levels focusing on:
Human interactions
Most threats are likely to be caused as a result of human mismanagement of the habitat due to residential, infrastructural and commercial development, agriculture and forestry, energy production and mining, transportation, hunting and collecting, accidental introductions and recreational activities. Abandonment of land, elimination or reduction of grazing in grasslands, and overgrowth are also other relevant causes for loss of CWR biodiversity.
What should I do?
Interact with people responsible for the threats and adopt measures to limit any harmful activities. Eventually, you may need some kind of agreement/regulation to ensure their effectiveness and prevent any recurrence.
For example, you can include activities such as meetings with local authorities and community leaders to explain the value of the site and to implement agreements on how to limit the impacts. Other activities that you could consider are awareness campaigns to educate local people.
Important
Develop a specific action plan. Include this plan in the Management Plan of your genetic reserve.
Physical environment
Attempt management interventions in the physical environment only when severe damage has been caused to the habitat (e.g. habitat loss, fire, chemical pollution, flooding, etc.).
Interventions may involve the excavation or earth filling to change the topography of the site to control or prevent soil erosion, for soil amelioration, retention of soil moisture, and/or drainage improvement. They may be needed as a result of habitat alteration after a great fire, intensive logging and wood harvesting, intensification of agriculture and housing and commercial development in the surroundings. It should be carried out by experts in habitat restoration bearing in mind the needs and limitations of the target CWR species. Although they can seem highly impacting at first, these kind of interventions can be essential for a long-term improvement of the habitat.
A much simpler intervention of the physical environment involves fencing the genetic reserve to prevent access to humans (e.g. in recreational areas with large human visitation rate) or to cattle. However, the former may be undesirable and the latter may end up being harmful for the CWR populations, so this type of intervention should be used with caution (Shands, 1991).
Biotic interactions
Other than humans, the biotic community can have a profound influence (both positive and negative) on the target CWR populations you are trying to protect. This biotic community may include beneficial species, such as pollinators and seed dispersers which are important for the survival and regeneration of the target CWR species, but they can also be other plants or animal species that are competing with or predating on the target species, as well as pest and diseases.
Management interventions will very much depend on both the type of habitat and biotic components interacting in the site. Some common measures may include:
A) Eradication or control of introduced mammals which may cause overgrazing, soil trampling, seed predation and nitrification. Techniques include trapping and relocation, exclusion with fencing and culling.
B) Chemical and/or biological control of pests and diseases.
C) Control of invasive exotic plants through manual removal, biological control, mowing and/or selective herbicide applications.
D) Population enhancement of useful species, such as pollinators and seed dispersers, either directly or through the creation of appropriate nesting sites, or microhabitats, or plant species that act as facilitators for the target species providing optimal shading conditions or protecting from wind or extreme temperatures.
E) Control of genetic pollution from crops that can potentially cross with the target CWR populations by avoiding their cultivation in a buffer area around the genetic reserve.
Please note that implementing any of these measures should be carefully assessed, taking into account all potential direct and indirect effects.
Target CWR populations
Management interventions to regenerate or reinforce target CWR populations should only be applied in extreme situations where, for some reason (e.g. habitat destruction, pests, diseases, fire, etc.), population size has decreased dramatically, and population trends are declining.
As much as possible, regeneration of target CWR populations should be done in situ. This can be achieved by applying some of the measures discussed under the 'human interactions', 'physical environment' and 'biotic interactions' sections.
However, if these measures are not sufficient the population can be reinforced and threats minimized. This may simply consist of collecting seeds or other propagules from plants of the target populations and spreading them in the same population. If seed recruitment or early life stages of the plants are very vulnerable at the natural site, seeds can be germinated elsewhere, and plantlets transferred back to the natural site at the most appropriate time.
Since you are interested in conserving the genetic diversity of the target population, reinforcement with plant material from other populations should not be considered. It is highly advisable to collect a representative sample of seeds of the target CWR populations and to conserve them ex situin collaborating gene banks. It is important to repeat this task at appropriate intervals of time to record and store any changes in the populations' genetic diversity. These seed accessions would be of great value to perform a reinforcement intervention when needed.
These types of operations are highly complex and should be carefully prepared following the indications and suggestions provided in specialized literature (Guerrant et al., 2004; Hunter and Heywood, 2011; IUCN/SSC, 2013). If the genetic reserve is subject to threats which will take a long time to reduce, quasi-in situ conservation approaches (Volis and Blecher, 2010) may also be considered. Plant propagules obtained from the target population are then translocated and established in nearby-areas with similar habitat conditions, where they can be further propagated to provide locally-adapted plant material to be later used in the reinforcement of the original population.