Hedgerows along field boundaries and woody vegetation associated with streams and watercourses may receive less attention than the large grasslands and trees of the dehesa, but they perform essential functions. They provide food and shelter, protect livestock from heat, wind and cold, and help conserve soil, water and biodiversity.
Not every part of an extensive livestock holding needs to perform the same function. Grasslands provide the basis of livestock feeding, trees offer shade, browse and fruit, and scrub diversifies the resources available. But other, apparently secondary, landscape elements can also play a decisive role: hedgerows, vegetated boundaries and riparian woodland associated with watercourses.
The LIFE ScrubsNet document “Livestock and scrub management for dehesa regeneration” highlights that maintaining patches of woody vegetation in the form of hedgerows, small woodland patches and riparian formations creates genuine islands of fertility and biodiversity, helping to improve the stability and resilience of the livestock ecosystem.
Hedgerows: much more than field boundaries
Hedgerows are formations of shrubs and trees that can be conserved or established along paddock and field boundaries.
Their function goes far beyond marking property or grazing limits. When they contain a good diversity of species, they can provide leaves, browse and fruit that supplement livestock diets when herbaceous pasture becomes scarce.
They also act as shelter and provide protection against adverse conditions such as heat, wind and cold.
In a livestock system exposed to the strong seasonal variation of the Mediterranean climate, having these resources distributed across the holding can be particularly valuable during critical periods.
A source of food when pasture becomes scarce
The feeding value of a hedgerow does not depend solely on the amount of vegetation it contains. Its capacity to diversify the resources available is equally important.
Trees can provide browse, pruning residues and woodland fruit, while shrubs offer shoots, leaves and, depending on the species, flowers and fruit with different nutritional values.
Field edges therefore cease to be merely marginal spaces and become part of livestock management planning.
When appropriately conserved and managed, they can complement grassland without requiring the whole holding to become covered in scrub.
Riparian woodland: protecting watercourses
Alongside hedgerows, the protocol places particular emphasis on riparian woodland and scrub, meaning woody formations growing around streams and watercourses.
Many streams in the dehesa are temporary, but this does not reduce the importance of the vegetation growing along their margins. These areas can be especially valuable within the wider farm mosaic.
The document explains that conserving riparian vegetation can help prevent soil erosion, improve water quality, conserve biodiversity and complement the food supplied by herbaceous vegetation.
A stream and its associated vegetation should therefore not be viewed simply as a feature crossing the holding. They are also part of its ecological infrastructure.
Green forage during summer
The value of riparian vegetation may become even more evident in summer.
When grassland has dried out, shrubs in these areas and material from tree pruning can provide green forage of particular value to livestock.
This complementarity is especially relevant in Mediterranean systems, where feed availability changes substantially throughout the year.
Maintaining different types of vegetation provides resources at different times and reduces dependence on a single source of feed.
Shelter from the weather
The benefits of woody vegetation extend beyond food.
The protocol highlights its capacity to provide shade and shelter from cold, rain and wind. It can also help retain water and soil during heavy rainfall and thereby reduce erosion.
These formations can also create a local microclimate that favours the establishment of herbaceous communities and the growth of trees.
A hedgerow therefore benefits more than animals seeking food or shade. It can improve environmental conditions in its immediate surroundings.
Small corridors for biodiversity
Hedgerows, riparian formations, small woodland patches and other areas of woody vegetation also provide refuge for many species.
The document states that they can offer shelter, nesting sites and food for beneficial fauna, while also helping protect natural tree regeneration through the nurse-plant effect.
They can also supply resources for pollinators and woodland fruit for insect-eating birds during autumn and winter.
This network of small vegetated areas helps distribute biodiversity throughout the holding rather than concentrating it only in large scrub patches.
Field margins can also support regeneration
Woody vegetation along boundaries and other areas of the holding can also contribute to dehesa renewal.
The protocol explains that a controlled increase in native shrub cover can support the regeneration of hedgerows, boundaries and trees. Scrub can protect seeds and seedlings from grazing and contributes to processes such as nutrient recycling.
This makes certain field margins particularly suitable for allowing vegetation to develop under reduced grazing pressure.
Not every part of a holding needs to maximise short-term grass production. Some strips of land can provide services that increase long-term productivity, diversity and resilience.
Conserving rather than simplifying
There may be a temptation in livestock management to remove vegetation from boundaries in order to increase usable land or simplify farm operations.
The LIFE ScrubsNet approach encourages managers to consider which functions are lost when these elements disappear.
A hedgerow can provide food, shade and shelter. Riparian vegetation can protect soil, improve water quality and maintain biodiversity. A scrub patch can protect the trees of the future.
Each may occupy a relatively small area, but its influence can extend far beyond its physical boundaries.
A green network within the dehesa
The dehesa is not simply a landscape of scattered trees over grassland.
Its edges, boundaries, shrubs, small woodland patches, streams and associated vegetation are also part of the system. Together they create a mosaic that provides food, shelter and ecological services throughout the year.
The LIFE ScrubsNet message is clear: conserving hedgerows and riparian vegetation means using existing landscape elements to combine livestock production with the protection of soil, water, biodiversity and dehesa regeneration.
Sometimes, an important part of the solution lies precisely in those discreet spaces surrounding paddocks and following streams.
The LIFE ScrubsNet project is co-funded by the European Union through the LIFE programme, LIFE20 NAT/ES/000978.