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Home » Practical Cases » Pteridium Project. - Adaptation to climate change in the Cantabrian Mountains by controlling common fern (Pteridium aquilinium) populations in a circular economy system

Pteridium Project. - Adaptation to climate change in the Cantabrian Mountains by controlling common fern (Pteridium aquilinium) populations in a circular economy system

Autor de la imagen: Javier Incera Goyenechea/Fototeca CENEAM

The project "Adaptation to Climate Change in the Cantabrian Mountains through the control of common fern (Pteridium aquilinum) populations in a Circular Economy system" led by the Association of Sustainable Municipalities of Cantabria, in addition to having the support of the Ministry for Ecological Transition through the Biodiversity Foundation, had also with the participation of the Environmental Research Center (CIMA), the Institute of Biomedicine and Biotechnology of Cantabria (CSIC-IBBTEC) and the Cultural Association Bosques de Cantabria. The Pteridium project  has aimed to analyse the economic viability of controlling common fern (Pteridium aquilinum) populations in a circular economy system for adaptation to climate change in the Cantabrian Mountains, reducing forest fires caused or favoured by the presence of climate change, by controlling their expansion in an environmentally friendly way.

In addition, some active ingredients have been obtained from the plant residue resulting from the elimination of the fern, such as ecdysone and its ecdysteroid counterparts, studying the economic profitability of its commercialization for its use as a biological insecticide, economically profitable and ecologically proven.

Case Study Description
Challenges: 

Fern species of the genus Pteridium are considered among the most successful invasive plants. In particular, the common fern (Pteridium aquilinum) is one of the most abundant plant species in the Cantabrian Mountains and is also widely distributed. It is a native species with exceptional adaptability to temperatures, rainfall, and various locations. However, under certain circumstances, especially due to cultural factors or the lack of effective methods for its removal as in the past, it has become invasive, occupying most of the abandoned farmland and forests. These plants exhibit rapid and robust growth, creating extensive shaded areas in the understory.

Its large shrub masses pose a significant risk factor for the spread of forest fires during drought conditions, as they serve as highly flammable fuel.

Moreover, the common fern demonstrates remarkable resilience to fire, which not only stimulates the germination of its spores but also leaves its rhizomes largely unaffected, allowing it to resprout quickly after fires.

These characteristics, along with its extensive chemical and allelopathic arsenal, promote its invasive and colonizing tendencies compared to other native species, which are generally less harmful in these respects. This dynamic leads to a reduction in biodiversity in the affected areas.

Based on these considerations, the main challenge of the project was to determine the economic viability of controlling populations of the common fern (Pteridium aquilinum) in certain locations of the Cantabrian Mountains within a circular economy framework for climate change adaptation. This approach aimed to develop a replicable and effective method of forest management that would:

  • Reduce the risks of forest fires caused or exacerbated by large fern masses.
  • Control their spread in an environmentally friendly way through continuous selective mowing.
  • Minimize the costs associated with mowing and control efforts by obtaining and recovering industrial products from the removed material.
Objectives: 

The general objective of the project was to determine the economic viability of adapting to climate change in the Cantabrian Mountains by controlling populations of the common fern (Pteridium aquilinum) within a circular economy system.

Based on the biological characteristics of the ferns and in line with this objective, four specific goals were fundamentally established for the project’s execution:

  1. Reduce the risk of forest fires caused or exacerbated by the presence of Pteridium aquilinum by controlling its expansion through environmentally friendly methods.
  2. Extract active ingredients from the plant residue produced during the elimination of ferns, assessing the potential economic profitability of their commercialization as a biological insecticide.
  3. Develop a public awareness campaign to inform the public about the risks posed by the excessive proliferation of P. aquilinum in the context of climate change, as well as its harmful effects on biodiversity and health (both human and livestock).
  4. Disseminate and promote the project’s results to facilitate their application, replication, and improvement.
Adaptation measures implemented in the case study: 
Structural/physical: Technology options
Structural/physical: Ecosystemic options
Institutional: Economic options
Institutional: National and governmental policies and programs
Social: Information options
Social: Behavior options
Solutions: 

In order to meet the proposed objectives, the measures adopted in the development of the project were the following:

  1. Eliminating fire risks in a pair of experimental plots, each covering an area of 2 ha, located in the municipalities of Colindres and Liendo. This involved:
  2. Removal of flammable material: An initial clearing and crushing of the ferns located in each of the plots were carried out in autumn, just at the end of the plants' vegetative period. This timing ensured that they did not resprout until the following spring. The crushed biomass was degraded directly on the ground, providing nutrients to the soil. As a result, the presence of dry ferns in the cleared areas was avoided during autumn and winter, completely eliminating their high flammability potential.
  3. Preventing the reappearance of flammable material: In spring, selective clearing was carried out periodically in both plots, organized by sector, to address regrowth. It was observed that new outbreaks consistently occurred, even in sectors cleared three consecutive times (every 21 days). However, in the most frequently cleared sectors, the biomass was significantly reduced (approximately 75%). Consequently, it was proposed for future actions to extend the clearing period until August to further deplete the rhizome reserves.
  • Recovery actions: These focused on characterizing and extracting active ingredients from fern plant waste to evaluate the potential profitability of their production and commercialization as biological insecticides. Specifically:
  • Extraction and quantification of active ingredients: Significant amounts of ecdysone were detected in certain parts of the plant, demonstrating high insecticidal capacity and harmlessness to vertebrates, plants, and other organisms.
  • Studies of bioavailability and biological activity: Ecdysteroids (β- and α-ecdysone) were identified in fern fronds. Neurotoxicity studies, using a human neuroblastoma line (IBBTEC), and efficacy tests on pest-causing insects (CSIC) such as Myzus persicae and Rhopalosiphum padi were conducted, with the former being the most sensitive to the extracts.
  • Market potential assessment: The results indicate a real opportunity for commercialization, supported by existing environmental strategies, favorable legislation, and new technologies that enable further developments.

4. Citizen awareness campaign: Conducted during the project's execution through various communication efforts, including the preparation of materials such as leaflets, posters, and presentations, as well as press releases.

Importance and relevance of the adaptation: 

The different expected climate change scenarios may provide a possible advantage for the propagation and proliferation of large fern masses in the Cantabrian Mountains, given the remarkable adaptability of the common fern (Pteridium aquilinum). This potential increase in combustible biomass, especially during times of extreme drought, poses an intrinsic danger for the development of forest fires in the area.

The development of a system for the management and control of common fern populations in this area represents a measure of local adaptation within a circular economy framework, reducing forest fires caused or exacerbated by the presence of these ferns in an environmentally friendly manner.

Additional Details
Stakeholder engagement: 

The idea for the project originated from the Bosques de Cantabria Cultural Association, an entity that coordinated the various actions carried out, under the supervision of the Association of Sustainable Municipalities of Cantabria (MMSC).

It received support from the Biodiversity Foundation of the Ministry of Agriculture and Fisheries, Food and Environment, along with collaboration from the Institute of Biomedicine and Biotechnology of Cantabria (IBBTEC), the Center for Environmental Research (CIMA) under the Ministry of University and Research, Environment and Social Policy of the Government of Cantabria, and the City Councils of Colindres and Liendo.

In this context, the MMSC oversaw the technical and administrative management of the project, in partnership with the Bosques de Cantabria Cultural Association, while IBBTEC provided laboratory and technical analysis support.

Project interest: 

The main problem with eliminating P. aquilinum populations is that its rhizome is deeply buried, making it very difficult to uproot. If the soil is disturbed, the only result is the elimination of the accompanying flora, leaving P. aquilinum with full potential for vigorous regrowth and no competition. The use of herbicides is also not advisable due to their high cost and soil toxicity. Thus, it becomes necessary to adopt alternative strategies.

In this project, the application of selective clearing techniques has been tested, which keep the rest of the plants intact, allowing them to gain certain growth advantages. These advantages help to shade the new shoots that may arise after clearing. The aim is to deplete the energy reserves of the rhizomes by repeating the process several times so that the fern eventually becomes exhausted or, at the very least, produces stunted individuals with a reduced load of flammable material.

On the other hand, implementing risk elimination actions, such as clearing and control tasks, involves a high labour cost. Therefore, another point of particular interest in the project has been to reduce this cost by obtaining and recovering by-products from the eliminated material. In this sense, the viability of extracting and obtaining a chemical product such as ecdysone offers a way to make these types of interventions profitable. From the extracted ecdysteroids, a biological insecticide can be produced that would allow pests to be controlled in crops or garden plants in an environmentally friendly way, as it causes premature molting in insects but has no effect on other fauna and plants.

The conclusions of the project have been:

Risk Elimination Actions

  1. Actions were carried out in experimental plots with an area of 2 hectares each, located in the municipalities of Colindres and Liendo.
  1. Removal of flammable material. In autumn 2017, an initial clearing and crushing of the ferns was carried out in each plot. As this action was performed at the end of the plant's vegetative period, it did not resprout until the following spring. The crushed biomass decomposed directly on the ground, enriching it with nutrients. In this way, during part of the autumn and winter, the presence of dry ferns on the ground was avoided in the cleared areas, thereby completely eliminating their high flammable potential.
  2. Preventing the reappearance of flammable material. In spring 2018, from the moment the ferns began to sprout (April), selective clearing was periodically carried out in both plots, which were divided into sectors. In each sector, a different number of clearings were conducted (1, 2, or 3) to study the plant's response. After clearing, it was observed that regrowth occurred in all cases, even in those sectors where action had been taken three consecutive times (every 21 days).

However, when quantifying the regrowth, it was found that in the sectors cleared most frequently, the biomass was considerably reduced (approximately 75%). For future campaigns, it is recommended to extend the clearing period until August to further deplete the rhizome reserves.

2. Valuation Actions

a. Extraction and quantification of active ingredients. At different points during the project, various types of samples and extracts from the plant were taken to quantify the amount of ecdysone present. This biomolecule has insecticidal properties and is harmless to vertebrates, plants, and other organisms. Preliminary results indicate a high concentration of this hormone in specific parts of the plant.

b. Study of bioavailability and biological activity. LC-MS analyses of the samples so far indicate that the highest content of ecdysteroids (β- and α-ecdysone) is found in the fern fronds. In anti-feeding activity tests, a correlation was observed between the ecdysteroid content and the anti-feeding activity against aphids (M. persicae and R. padi), with M. persicae being the most sensitive insect to these extracts.

c. Market Potential. Five trends have been identified that suggest a window of opportunity for the development of new, natural-origin alternatives for pest control and management, such as ecdysteroids:

i. Global agricultural production needs.

ii. Market demand and changes in production chains.

iii. Biopesticides as part of strategies employed by major market leaders.

iv. National and international legislation aligned with the use of biopesticides.

v. New technologies enabling innovative developments

Success and limiting factors: 

The control of natural populations of Pteridium aquilinum has traditionally been carried out through the application of herbicides (a method that is costly and often has undesirable environmental effects), controlled fires (which can sometimes exacerbate the problem), or periodic mowing (a more effective system but expensive due to the high labor costs involved).

In addition, Pteridium aquilinum possesses a significant chemical arsenal that is allelopathic to other plant species and toxic to many animal species, including livestock and even humans (e.g., thiaminase, HCN, ptaquiloside, among others). While some of these chemicals can be beneficial and usable, exposure to others can occasionally be particularly harmful.

The project’s greatest success lies in demonstrating the effectiveness of continuous selective mowing techniques in controlling and limiting the propagation of ferns. This approach has reduced the associated costs by utilizing the plant residue for the extraction and purification of chemical compounds such as ecdysone, which has the potential to become an important economic resource, adding value to these management actions.

Thus, identifying, characterizing, extracting, purifying, and commercially formulating the fern's chemical compounds of industrial interest, such as ecdysteroids, may prove essential for the continued use of these mowing techniques to control fern biomass. This would help reduce costs while fostering the development of a locally applied industry.

Budget, funding and additional benefits: 

In terms of budget, the project amounted to a total cost of € 53,239.01 for which financing was supported by the Ministry of Agriculture and Fisheries, Food and Environment through the Biodiversity Foundation, which contributed € 28,565.95 (53.66%).

The rest, €24,673.06 (46.34%) were contributed by the Environmental Research Centre (CIMA) of the Ministry of University and Research, Environment and Social Policy of the Government of Cantabria, which contributed €14,850.00 (27.83%) and by the Association of Sustainable Municipalities of Cantabria, which contributed €9,050.00 (16.96%).

Budget items have been allocated to staff costs, travel and subsistence, external assistance, inventoriable material, consumables and overheads.

Legal aspects: 

The development of this project is affected by the local and regional regulations for the exploitation of crop farms, as well as those dedicated to livestock, forest lands and mountains of public utility. 

The results of the project have been sent to the Government of Cantabria for assessment within the framework of regional management plans, strategies and instruments.

On the other hand, the extraction of ecdysteroids from the plant remains obtained and the development and marketing of possible natural insecticides from them, imply the impact of broader national and international legislation, aligned with the use of biopesticides.

In this sense, biocidal products are regulated at European level by Regulation (EU) No. 528/2012 of the European Parliament and of the Council of 22 May 2012. However, each Member State authorises the placing on the market of biocidal products within its borders separately, although biocidal active substances are approved at Community level. In Spain, Royal Decree 971/2014 is the one that regulates the evaluation procedure for these phytosanitary products.

In any case, biocidal products may only be marketed and used in the national territory if they have been previously authorised and registered in the Official Register of Biocides. The list of approved active substances can be consulted at the European Chemicals Agency (ECHA) and the procedure and requirements can be consulted at the Directorate General for Public Health and Foreign Health of the Ministry of Health, Social Services and Equality.

Implementation time: 

The project lasted 10 months, running between August 2017 and June 2018.The project lasted 10 months, running between August 2017 and June 2018.

Reference Information
Contact: 
  • Javier Hernández Blanco

Technical Director

Association of Sustainable Municipalities of Cantabria

Email: hernandez-j@municipiossostenibles.com

Phone: 942663111

  • Eduardo Clemente Rasines del Río

President of the Cultural Association Bosques de Cantabria

Email: info@bosquesdecantabria.org

Telephone: 609 668 673

Websites: 
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