1. Context
Dehesa of Siruela pilot farm is located in the municipality of Siruela, in Badajoz. The municipality of Siruela is the owner of the farm, which covers an area of 7,500 ha. The dehesa is largely within RN2000. The farm has a communal management, in which different farmers and livestock breeders of the municipality lease lots of the same for their exploitation on an annually basis. The farm is divided into areas with cereal crops and fallow areas for sheep pasture. Crops are rotated every four years. There is an area of the farm that is not suitable for sowing, being used only as permanent pasture for livestock.
The dehesa habitat in general is quite degraded, with limited regeneration of trees and practically no brush. The holm oaks are very old.
During the previous visit to the farm in the spring of 2022, some interesting elements and places for the implementation of the project actions were identified:
• The meadow is crossed in its northern part by a royal cattle track (not yet demarcated) that the municipality wants to recover (Vías pecuarias has required them to act on several occasions). So they plan to install a fence this year to delimit the cattle track for several kilometers. This is an element that can be considered in the project.
• There is the option of reserving an area of the farm (extension to be considered according to budget and agreement with the city council), in the area of non-arable permanent pastures, to concentrate different actions of regeneration, planting of islands of biodiverse scrub, naturalization of livestock pond, wildlife refuges, etc…). This area could be fenced perimetrically to ensure protection against livestock and wild animals, and act within it. Small ponds for amphibians and reptiles could be included in this area (actions to improve water points).
• An existing livestock pond is identified in which naturalization and study of a model for improvement in a livestock pond is proposed.
2. Actions
Following the two visits, the specific actions to be implemented on this farm in relation to actions C1, C2, C3 and C4 are defined below:
Measure 1: Naturalization of cattle pond
A pond located in the central-western area of the mountain has been selected that maintains water throughout the year, an uncommon feature in the environment where there are multiple ponds that dry up during the summer season. The field visits carried out at different stations revealed a significant degradation of the slope that acts as a retaining wall, with scarce vegetation cover and the formation of gullies caused by the continuous transit of livestock.
Actions carried out
Protection and spatial planning:
- Installation of a perimeter enclosure of approximately 250 linear meters with livestock mesh to protect the areas under rehabilitation
- Enabling dedicated side access for maintenance personnel
- Interior fencing that delimits a third of the water surface, allowing livestock to access the shallower area to water while protecting the areas under restoration
Stratified revegetation:
Front line (banks of the pond): 100 specimens of marsh and aquatic species:
- Carex pseudocyperus (Sedge)
- Eleocharis palustris (Lagoon rush)
- Cyperus longus (Smelly sedge)
- Scirpoides holoschoenus (Churrero Rush)
- Iris pseudacorus (Yellow Lily)
- Mentha aquatica (Water Mint)
- Mentha pulegium (Pennyroyal)
- Phalaris tuberrosa (Tuberous birdseed)
Second line (slope and perimeter): 100 specimens of shrub species:
- Nerium oleander (Oleander)
- Frangula tinctoria (Arraclán)
- Dog Rose (Wild Rose)
Regeneration of the tree layer:
- Planting of 50 holm oak acorns encapsulated using various techniques in the area around the drainage, from specimens from the farm itself
Infrastructure for biodiversity:
- Insect Hotel Installation
Objectives
Renaturing the pond, stabilising the slope and recovering the ecological corridor associated with the drainage area, creating a functional ecosystem that combines livestock use with the conservation of aquatic and riparian biodiversity.
Measure 2. Regeneration of cultivation and grazing area
An area of 1.5 hectares has been fenced that integrates areas of cultivation and sowing of cereals together with grazing areas, including a pond, its drainage and natural rock accumulations. This enclosure allows various restoration actions to be implemented in a coordinated and protected manner. The project integrates multiple ecological restoration techniques – hydraulic, soil and vegetation – aimed at recovering the functionality of the dehesa ecosystem. The combination of water infiltration actions, stratified revegetation, creation of microhabitats and protection of sensitive areas makes it possible to make traditional livestock use compatible with the conservation and improvement of biodiversity, establishing the foundations for a more resilient and productive system in the long term.
Actions carried out
2.1. Enclosure
The enclosure consists of a simple twisting mesh of 148 cm in height and variable span, anchored on treated wood posts of 4-6 cm in diameter every 5 meters, braced every 50 meters with 50x50x5 mm steel metal braces. In addition, this enclosure has a double-leaf access door for vehicles. This infrastructure has been topped in some areas with gabion walls to prevent the passage of fauna in areas where the mesh is not at ground level. A few meters downstream from the pond that is inside this enclosure, drinking troughs for cattle have been installed, since that pond is currently inaccessible. An infrastructure has been installed to pump water from the pond to the drinking fountains, including a level sensor so that the filling works according to the demand for water.
2.2. Plantations
- Regeneration of trees using encapsulated acorns: Planting of 75 holm oak acorns (Quercus ilex) collected on the farm itself and encapsulated, strategically distributed within the fenced enclosure.
- Revegetation of the pond: 250 plants on the front line, 250 plants in the second line and 4 ceramic pots with reeds inside the water surface to facilitate natural colonization
- Rock structures for pollinators: In the surroundings of the pond, 5 rock accumulations have been built (approximately 1.5 × 1.5 meters at the base and 0.5 meters in height) located according to the availability of stone material in the enclosure. Topsoil has been provided on each structure and 10 specimens per structure (50 plants in total) of the same mixture of species used in the gabions have been planted in the hollows, creating microhabitats for pollinators and small fauna.
2.3. Protection of springs by means of gabions and seeding
During the field visits, three points were identified where water emerges and persists during the summer months. To protect the springs, dry stone gabions and shrub plantations have been implemented. In total, 20 linear meters of gabions ( 1 meter high × 0.5 meters wide) to protect areas with natural springs or springs, heavily trampled and degraded by livestock. With these dry stone constructions, the water is filtered and continues its course, generating accumulations of water and preventing the trampling of these springs by livestock. Up to three springs have been protected, with a volume of 10 cubic meters of gabions. The stone has been collected in the pasture itself and its configuration has been in crossed sections and parallel to the stream on both sides, acting as a barrier that prevents direct access by livestock without hindering the flow of water. Along the gabinas, 80 specimens of native scrub have been planted, distributed among the species Sage Spp. Retama sphaerocarpa, Lavandula stoechas and Quercus ilex.
2.4. Infiltration lines (swales)
Execution of 200 linear meters of small trenches following the contours of the terrain to favor the retention and infiltration of runoff water. These ditches have been filled with pruning remains and local branches to prevent exposure and erosion. Surface soil has been provided on them and native herbaceous species have been planted, thus improving the capacity of water capture and storage of the soil on the hillside.
2.5. Installation of insect hotels
4 insect hotels built with remains of branches, reeds and wood, distributed inside the enclosure after the work was completed
Measure 3. Shrub Islands for Biodiversity Enhancement
A total of 16 islands have been planted on the farm, distributed as follows:
- Surroundings of the small cattle pond: 6 islands of 36 m² each, protected with electrowelded mesh, with 180 seedlings per island and 12 species selected according to their ecosystem function in the dehesa
- Interior of the enclosure of 1.5 ha: 10 scrub islands, with 156 plants per island (12 species with 13 specimens of each)
Monitoring results (after 2.5 years): Mean survival rate of 39%. Generally speaking, most species show acceptable survival rates. The differences observed reflect the different ecological requirements of each species and their ability to adapt to the soil and climatic conditions of the site and to the pressure of livestock in non-protected areas.
Most successful species:
- Cistus monspeliensis (Rockrose of Montpellier): 65%
- Salvia officinalis (Common Salvia): 68%
- Phillyrea angustifolia (Labyrnago): 55%
- Teucrium fruticans (Olivilla): 51%
Species with the lowest survival:
- Arbutus unedo (Strawberry Tree): 11%
- Myrtus communis (Myrtle): 15%
Measure 4. Construction and installation of wildlife shelters on the farm
4.1. Construction of amphibian ponds
7 small ponds have been built using a backhoe to serve as a refuge for amphibians and reptiles.
4.2. Installation of nest boxes
Birdlife: 10 nest boxes for passerines installed in holm oaks inside and around the fence
Chiroptera: 10 bat shelters located in trees on the periphery of the fenced area, within their area of influence
