Dehesa regeneration does not depend on a single measure. Trees, scrub, grassland, livestock, soil, water and biodiversity form part of the same system, and decisions affecting one component influence the others. The LIFE ScrubsNet protocol brings together knowledge and management tools to support more diverse, functional dehesas capable of maintaining their productive and environmental values over time.
Throughout this series we have explored natural regeneration, nurse shrubs, forage species, grazing calendars, fencing, plant guards, browsing assessment and mixed grazing. These may appear to be separate issues, but they all lead to the same conclusion: the dehesa needs to be managed as a system.
The LIFE ScrubsNet document stresses that a system is defined by the relationships between its components and warns that using one element without considering its links with the others can lead to unexpected outcomes.
More than trees scattered across grassland
A well-managed dehesa is not simply a collection of holm oaks or cork oaks standing over grass.
The protocol describes it as an intimate mixture of different habitats, bringing together woodland elements, grassland, scrub and sometimes crops. This diversity allows woodland organisms and species associated with open habitats to coexist.
Problems arise when this system becomes excessively simplified. The disappearance of scrub and excessive pressure on vegetation can create a landscape that appears productive in the short term but is less stable and less able to replace ageing trees.
Scrub is also part of the solution
One of the central ideas in the LIFE ScrubsNet approach is to reconsider the role of shrub vegetation.
The objective is not uncontrolled scrub expansion. It is to maintain an appropriate amount and distribution of scrub according to the characteristics and objectives of each area.
The document explains that controlled increases in shrub cover can support natural tree regeneration and increase the range of grazing resources available, although associated risks must also be managed.
Scrub can protect seeds and young trees from livestock, contribute to nutrient cycling and create conditions that support regeneration.
Grass, trees and shrubs: complementary resources
Plant diversity also provides different resources at different times of year.
Herbaceous pasture is a fundamental component of extensive livestock diets. Trees can provide browse, pruning residues and woodland fruit, while shrubs add shoots, leaves, flowers and fruit with different nutritional characteristics.
Managing the dehesa therefore means finding a balance between these resources rather than maximising one by removing the others.
Soil and water matter too
Woody vegetation also performs functions that extend far beyond livestock feeding.
On steep, shallow or rocky ground, woody plants can help retain and build soil. Scrub patches, hedgerows, small woodland areas and riparian vegetation can also create islands of fertility and biodiversity, increasing the stability and resilience of the livestock ecosystem.
Along watercourses, conserving woody vegetation can help reduce erosion, improve water quality and maintain biodiversity.
Livestock are also a management tool
Livestock should not be seen simply as consumers of what a holding produces.
Species, breed, stocking rate, timing, duration of grazing and grazing behaviour all influence vegetation.
The protocol therefore combines approaches such as temporarily resting paddocks, protecting selected patches, rotational grazing, choosing less browsing-prone animals and mixed grazing. Different areas may require different objectives, from supporting young trees to conserving biodiversity islands or using scrub as forage.
Regeneration takes time
Lack of tree replacement is one of the major challenges facing many dehesas.
The document describes how the progressive loss of mature trees combined with insufficient regeneration has left many dehesas ageing without adequate replacement. It therefore emphasises natural regeneration and the need to protect young holm oaks, cork oaks and other Quercus species during their early development.
Regeneration means accepting that some management measures take years to deliver results.
Observe, measure and adapt
There is no single recipe suitable for every dehesa.
Soils, rainfall, vegetation, livestock, tree structure and management objectives differ from one holding to another.
This is why many LIFE ScrubsNet tools — monitoring browsing, adapting grazing calendars, rotating livestock, protecting selected areas and deciding which scrub to retain — form part of an adaptive management approach.
Observe what is happening, assess the results and adjust management where necessary.
Keeping the dehesa alive for the future
The message that concludes this series is also the one connecting everything that came before:
regenerating the dehesa is not simply about planting trees. It requires maintaining functional relationships between trees, scrub, grassland, livestock, soil, water and biodiversity.
LIFE ScrubsNet provides knowledge and management tools for working with these relationships and supporting mosaic landscapes that combine livestock production, natural regeneration and conservation.
A dehesa with a future is not necessarily the one with the least scrub, the most grass or the greatest number of animals.
It is one that maintains enough balance to continue regenerating itself.
The LIFE ScrubsNet project is co-funded by the European Union through the LIFE programme, LIFE20 NAT/ES/000978.