Evidence Platform
Dominant plant species modulate responses to hydroseeding, irrigation and fertilization during the restoration of semiarid motorway slopes
Garcia-Palacios, P., et al., 2010. Ecological Engineering
Original research (primary data)View External Publication Link
Abstract
Restoring roadside slopes in semiarid regions of the Mediterranean Basin is often constrained by the difficulties arising when developing restoration projects (absence of nearby natural ecosystems serving as reference sites and slow natural colonization) and by the contradictions found between short-term (reduce soil erosion) and long-term (increase plant diversity) restoration goals. Restoration techniques developed in temperate climates are commonly applied in these regions without taking into account their specific characteristics; as a consequence, they often fail. We evaluated the effectiveness of three treatments widely used by practitioners (hydroseeding, fertilization and irrigation) to foster community composition changes that control soil erosion and increase species diversity (restoration goals) during the restoration of motorway embankments. The study was carried out during an 18-month period in five embankments from semiarid central Spain. The most outstanding result was that responses of the plant community to the treatments evaluated were site-specific. Several fast-growing dominant species, some hydroseeded and some already present in the study sites, were responsible for this idiosyncratic variation between sites. On embankments, where plant cover can easily reach values high enough to prevent erosion, the use of non-native herbs that can potentially dominate the community should be avoided. These fast-growing species, although effective as starters the first years following motorway building, can constrain vegetation dynamics in the long term. Our results indicate that these species should be controlled in the field, and their presence avoided in the commercial seed mixtures when the target is to enhance biodiversity and ecosystem stability and resilience.
Case studies
Basic information
- Case ID: INT-162-2
- Intervention type: Created habitats
- Intervention description:
Experimental -testing restoration technique on slopes near a motor-way that were degraded. Used 'hydroseeding' - Most of the species hydroseeded are non-native to Spain, which is the norm in restoration projects in the Mediterranean Basin "The stabilization of slopes and the control of soil erosion through the establishment of a dense herbaceous cover is a priority in the restoration of recently built roadside slopes ...The com- mercial hydroseeding mixtures are mainly composed by highly competitive forage grass and legume species non-native to these areas" [In addition to the hydroseeding also included] ...Restoration treatments were either fertilization (applied twice - a 20 g/m2 dose of a slow release N:P:K (16:11:11) inorganic fertil- izer) or irrigation (conducted from March to June in both 2007 and 2008, coin- ciding with the peak growing season of annual plant communities characterizing our study sites; at a level of 50% of the monthly total precipitation median from the 1971 to 2000 period). Also tested combo of fertilization and irrigation
- Landscape/sea scape ecosystem management: No
-
Climate change impacts Effect of Nbs on CCI Effect measures Soil erosion No effect volume of soil mobilized in each plot between beginning and end of experiment as a surrogate of soil erosion - Approach implemented in the field: Yes
- Specific location:
The study area is located in the R4 and AP36 motorways, between Pinto (Madrid; 40◦14′N, 3◦43′W) and Corral de Almaguer (Toledo; 39◦45′N, 3◦03′W), in the centre of the Iberian Peninsula (altitude c. 700 m a.s.l.).
- Country: Spain
- Habitat/Biome type: Created grassland |
- Issue specific term: Not applicable
Evidence
- Notes on intervention effectivness: Effectiveness compared to control experimental plot where no active restoration intervention was applied.
- Is the assessment original?: Yes
- Broadtype of intervention considered: Another NbS plus other non-NbS approach(s)
- Compare effectivness?: Yes
- Compared to the non-NBS approach: Same
- Report greenhouse gas mitigation?: No
- Impacts on GHG: Not applicable
- Assess outcomes of the intervention on natural ecosystems: Yes
- Impacts for the ecosystem: Mixed
- Ecosystem measures: Species diversity (shannon’s), community composition, % plant cover
- Assess outcomes of the intervention on people: No
- Impacts for people: Not reported
- People measures:
- Considers economic costs: No
- Economic appraisal conducted: No
- Economic appraisal described:
- Economic costs of alternative considered: No
- Compared to an alternative: Not reported
Evaluation methodology
- Type of data: Quantitative
- Is it experimental: Yes
- Experimental evalution done: In-situ/field
- Non-experimental evalution done: Not applicable
- Study is systematic:
Basic information
- Case ID: INT-162-1
- Intervention type: Restoration
- Intervention description:
Experimental -testing restoration technique on slopes near a motor-way that were degraded. Restoration treatments were either fertilization (applied twice - a 20 g/m2 dose of a slow release N:P:K (16:11:11) inorganic fertil- izer) or irrigation (conducted from March to June in both 2007 and 2008, coin- ciding with the peak growing season of annual plant communities characterizing our study sites; at a level of 50% of the monthly total precipitation median from the 1971 to 2000 period). Also tested combo of fertilization and irrigation
- Landscape/sea scape ecosystem management: No
-
Climate change impacts Effect of Nbs on CCI Effect measures Soil erosion No effect volume of soil mobilized in each plot between beginning and end of experiment as a surrogate of soil erosion - Approach implemented in the field: Yes
- Specific location:
The study area is located in the R4 and AP36 motorways, between Pinto (Madrid; 40◦14′N, 3◦43′W) and Corral de Almaguer (Toledo; 39◦45′N, 3◦03′W), in the centre of the Iberian Peninsula (altitude c. 700 m a.s.l.).
- Country: Spain
- Habitat/Biome type: Mediterranean shrubs and Forests |
- Issue specific term: Not applicable
Evidence
- Notes on intervention effectivness: Effectiveness compared to control experimental plot where no active restoration intervention was applied. Results of erosion were not significantly different from the control therefore no effect. [Although at one site, irrigation treatment had significant effect compared to controls, it was not through its effect on plant biomass but due to water application itself. This outcome is therefore not relevant for us to code for.] Mixed outcomes for natural ecosystem b/c fertilization increased diversity at one site but caused a decrease in another site.
- Is the assessment original?: Yes
- Broadtype of intervention considered: Another NbS plus other non-NbS approach(s)
- Compare effectivness?: Yes
- Compared to the non-NBS approach: Same
- Report greenhouse gas mitigation?: No
- Impacts on GHG: Not applicable
- Assess outcomes of the intervention on natural ecosystems: Yes
- Impacts for the ecosystem: Mixed
- Ecosystem measures: Species diversity (shannon’s), community composition, % plant cover
- Assess outcomes of the intervention on people: No
- Impacts for people: Not reported
- People measures:
- Considers economic costs: No
- Economic appraisal conducted: No
- Economic appraisal described:
- Economic costs of alternative considered: No
- Compared to an alternative: Not reported
Evaluation methodology
- Type of data: Quantitative
- Is it experimental: Yes
- Experimental evalution done: In-situ/field
- Non-experimental evalution done: Not applicable
- Study is systematic: