Traditional Silvopastoral Systems Research Articles

Effects of livestock on arthropod biodiversity in Iberian holm oak savannas revealed by metabarcoding

Increasing food production while avoiding negative impacts on biodiversity constitutes one of the main challenges of our time. Traditional silvopastoral systems like Iberian oak savannas (“dehesas”) set an example, where free-range livestock has been reared for centuries while preserving a high natural value. Nevertheless, factors decreasing productivity need to be addressed, one being acorn losses provoked by pest insects. An increased and focalized grazing by livestock on infested acorns would kill the larvae inside and decrease pest numbers, but increased livestock densities could have undesired side effects on ground arthropod communities as a whole. We designed an experimental setup including areas under trees with livestock exclosures of different ages (short-term: 1-year exclusion, long-term: 10-year exclusion), along with controls (continuous grazing), using DNA metabarcoding (mitochondrial markers COI and 16S) to rapidly assess arthropod communities’ composition. Livestock removal quickly increased grass cover and arthropod taxonomic richness and diversity, which was already higher in short-term (1-year exclosures) than beneath the canopies of control trees. Interestingly, arthropod diversity was not highest at long-term exclosures (≥10 years), although their community composition was the most distinct. Also, regardless of treatment, we found that functional diversity strongly correlated with the vegetation structure, being higher at trees beneath which there was higher grass cover and taller herbs. Overall, the taxonomic diversity peak at short term exclosures would support the intermediate disturbance hypothesis, which relates it with the higher microhabitat heterogeneity at moderately disturbed areas. Thus, we propose a rotatory livestock management in dehesas: plots with increased grazing should co-exist with temporal short-term exclosures. Ideally, a few long-term excluded areas should be also kept for the singularity of their arthropod communities. This strategy would make possible the combination of biological pest control and arthropod conservation in Iberian dehesas.

Co-Creating Strategies to Optimize Traditional Silvopastoral Systems through the Management of Native Trees in Caívas in Southern Brazil

The conservation of forest remnants in southern Brazil is closely related to historical land use, for example in systems such as caívas that occur within remnants of the Araucaria Forest and include livestock production and the extraction of yerba mate. Over the last decade, technologies adapted for these systems have been developed that promote a significant increase in animal productivity, without harming forest regeneration or the maintenance of the tree layer. However, the fertilization of pastures proposed in the technology has also promoted greater growth of native trees, with a consequent increase in shade levels. This, in turn, has affected the maintenance of pasture and yerba mate in the understory. Thus, this study sought to develop a methodology to adjust shade levels based on forest management that adheres to the limits permitted by current legislation. The objective was to evaluate the effect of tree management to maintain 50% shade levels on environmental indicators in a caíva that has been implementing pasture improvement technology since 2013. Native tree management occurred in 2020 and 2022 and the results were compared with data from the floristic survey of the area carried out in 2013. The results indicate that although the adoption of forest management to adjust shade levels reduced the density of individuals, it did not affect forest diversity, nor the basal area of the caíva tree layer. As such, it is possible to maintain pasture and yerba mate production in the area. Strategies like this are fundamental so that the forest landscape can continue to offer a source of production while also supporting environmental conservation.

Viability of a macauba palm–Brachiaria grass intercropping system as an alternative to agroforestry production

In intercropping systems, shading is one of the main limiting factors for the development of plants in the understory, especially C4 plants. However, successful pasture production in silvopastoral systems can be achieved through proper spatial arrangement. This study provides fundamental information that validates the macauba-grass consortium. For 20 months, during two dry seasons and two rainy seasons, microclimatic and physical variables in an Acrocomia aculeata–Brachiaria decumbens intercropping system were monitored. The spacings of the trees were 5 m × 4 m, 6 m × 4 m, 7 m × 4 m, and 8 m × 4 m and were compared to a traditional pasture. The aboveground biomass in the intercropping system was estimated as well as its ability to assimilate atmospheric CO2 and store carbon. Macauba palm presence in the intercropping system had a regulatory effect on the microclimatic conditions of the understory, regardless of tree spacing and season. In spacing, wider, the intercropped forage biomass was satisfactory and similar to that in the monocrop pastures. The spacing 7 m × 4 m and 8 m × 4 m improved the understory microclimatic conditions, allowing efficient forage growth and thus offering livestock food and comfort. These values were equivalent to those of traditional silvopastoral systems that use woody plant species. The estimates of aboveground biomass, carbon stock, and CO2 assimilation in the intercropping system with a spacing of 8 m × 4 m were 1.6 times greater than those of traditional pastures. Therefore, here, we show for the first time that A. aculeata–B. decumbens grass intercropping system is a viable alternative agroforestry practice for tropical regions, since sufficient amounts of fodder are provided alongside beneficial environmental services, such as the efficient sequestration and storage of atmospheric carbon.

Effects of Domestic and Wild Ungulate Management on Young Oak Size and Architecture

Scattered oaks in traditional silvopastoral systems (i.e., “dehesas”) provide important ecological services. However, livestock intensification applied to these systems over the last century has affected the architecture of young oak plants. This unsuitable rangeland management practice jeopardizes the long-term system sustainability. Here we examine the alterations in architecture of regenerating oak plants in Mediterranean dehesas under three representative management regimes: (1) traditional management with extensive sheep grazing; (2) commercially driven management with extensive cattle grazing, and (3) native deer grazing at moderate stocking rates (<0.11 livestock units × ha−1). Plant architecture was considerably altered in cattle-grazed “dehesas”, finding a 50% reduction in plant height–diameter ratios, compared to sheep-grazed dehesas where plants with higher height–diameter ratios predominated. Young oak plants, however, showed less altered architecture and less probability of damage on shoot apex (0.20-fold difference) in areas with deer grazing at moderate stocking rates. In addition, those young oak plants with multi-stemmed individual architecture were more stunted (lower values of crown height–diameter ratio) in areas with livestock grazing than wildlife areas (0.78-fold difference). Shrub presence, under all management schemes, helped to increase in plant height, except when shrubs were located under tree canopies. Conversely, plants without shrub protection showed stunted architecture with well-developed basal diameters but short stature. Appropriate sustainable practices should include cattle stocking rate reduction, traditional sheep grazing promotion, nurse shrub preservation and fencing stunted individuals along with pruning basal sprouts. Our study indicates that management may have important consequences on dehesa regeneration via alterations of plant architecture and therefore on system sustainability.

The multifunctional role of linear features in traditional silvopastoral systems: the sabana de morro in Dolores (El Salvador) and the pastures with carob trees in Ragusa (Italy)

Traditional agro-silvo-pastoral systems are becoming each day more important, representing multifunctional systems that can contribute to the preservation of agrobiodiversity and of traditional knowledge and associated culture, to the wellbeing of local communities and to sustainable development of rural areas, as testified by the increasing interest regarding the Globally Important Agricultural Heritage Systems (GIAHS) Programme of the Food and Agriculture Organization (FAO). Despite many researches on traditional agro-silvo-pastoral systems tend to focus only on land uses and land use changes, is also important to analyse the different features that characterize cultural landscapes, as well as to produce detailed spatial maps, in order to preserve and valorise these systems as a whole. The paper intends to compare two traditional silvopastoral systems in two different continents and environments: sabana de morro (El Salvador) and pastures with carob trees (Italy), considered as good example of biocultural diversity. Both these sites are characterized by extensive cattle breeding in a hot climate under the shade of trees, whose fruits can also integrate the animal diet. The study analyzed the traditional landscape structure, with particular attention to the presence of linear elements, that act as property divisions and as ecological corridors, contributing to biodiversity at landscape scale. Sabana de Morro is characterized by a complex system of hedges that enhances the variety of species, while an extensive network of dry-stone walls divides the Sicilian pastures with carob trees. These two different types of linear elements created thanks to the local farmers’ knowledge are made of different materials but can play a similar ecological and social function, acting as a division between one pasture and another, as a delimitation of property boundaries, and are necessary to allow a correct pasture management. Despite the differences, these two traditional linear features deeply characterize the landscape structure and fragmentation, creating important microhabitat for many animal and vegetal species and a network of ecological corridors. For these reasons the conservation of linear features should be promoted at planning level, as well as their restoration. Thanks to the applied methodology, it was possible to identify peculiarities and vulnerabilities of linear features and of the systems as a whole, so that it will be possible to create effective management and conservation tools.

Trees Increase Ant Species Richness and Change Community Composition in Iberian Oak Savannahs

Iberian man-made oak savannahs (so called dehesas) are traditional silvopastoral systems with a high natural value. Scattered trees provide shelter and additional food to livestock (cattle in our study sites), which also makes possible for animals depending on trees in a grass-dominated landscape to be present. We compared dehesas with nearby treeless grasslands to assess the effects of oaks on ant communities. Formica subrufa, a species associated with decayed wood, was by far the most abundant species, especially in savannahs. Taxa specialized in warm habitats were the most common both in dehesas and grasslands, as expected in areas with a Mediterranean climate. Within dehesas, the number of species was higher below oak canopies than outside tree cover. Compared to treeless grasslands, the presence of oaks resulted in a higher species richness of aphid-herding and predator ants, probably because trees offer shelter and resources to predators. The presence of oaks changed also the species composition, which differed between grasslands and dehesas. In self-standing scattered oaks, ant communities did not differ between the trunks and soil below canopies. These results stress the conservation value of trees in dehesas; within grasslands, they offer an additional microhabitat for species that would otherwise be scarce or absent.

Intraguild predation of weevils by livestock reduces acorn pests in oak silvopastoral systems

Iberian oak savannahs are traditional silvopastoral systems in which acorns constitute a key food source for livestock. Acorn feeding insects provoke significant economic losses; however, the high natural value of Iberian oak savannahs precludes any chemical treatment. This paper shows a novel way of biological pest control based on promoting livestock predation on these insects. Female Curculio elephas (Coleoptera: Curculionidae) oviposit into developing acorns, which are prematurely abscised before reaching their potential size. Larvae still spend 20 days feeding on the cotyledons after acorn drop, being during this period very vulnerable to predation by livestock. We experimentally assessed that cows, pigs and sheep ate sound and infested acorns in the same proportion, so that infestation rates were lower in those Iberian oak savannahs in which livestock density was higher. An effective biological control of Curculio elephas weevils should involve an early predation of infested acorns by livestock, preferentially within 10 days after falling. Doing this, most larvae will be predated before completing their development and, in addition, the nutritional value of infested acorns will still be high (cotyledons not yet depleted by weevils). We encourage landowners to increase livestock densities during September–October, when the infested acorn dropping peaks. These increased densities should rotate over the farm and be maintained at the same plot for a maximum of 3 years in a row. Otherwise, a prolonged and concentrated livestock predation on sound acorns and seedlings would hamper long-term oak regeneration.

Evaluating Sustainability in Traditional Silvopastoral Systems (caívas): Looking Beyond the Impact of Animals on Biodiversity

Caívas are traditional silvopastoral systems that occur in the Araucaria Forest biome, Southern Brazil, in which animal production and erva-mate extraction are integrated. Participatory research was conducted in caívas in the Northern Plateau, Santa Catarina State, to identify strategies to intensify pasture use and increase animal productivity. To better understand the outcomes of these strategies, a sustainability assessment was conducted in properties that participated in the research (improved caívas; IC) and those that did not (traditional caívas; TC). The Sustainability Assessment of Food and Agriculture Systems (SAFA) tool 2.0.0 for smallholders was chosen as it evaluates the productive unit as a whole using environmental, social, economic, and governance indicators and is tailored for small-scale production. All evaluated indicators showed higher scores for IC properties in relation to TC. In general, the SAFA analysis showed that when evaluated as productive systems, TCs are a strategic option for rural development, as 65% of their indicators were evaluated as good. With the support of rural outreach and research and the adoption of appropriate technologies, this percentage increased to 86% in ICs. These results confirm that with adequate support caívas can significantly contribute to the development of more sustainable livestock farming in Southern Brazil.

Ecological structure and carbon storage in traditional silvopastoral systems in Nicaragua

Forests and agroforestry systems in the tropics play a decisive role in global carbon fixation strategies. The amount and type of coverage, along with the specific land use and land use change in a given area, determines whether carbon is stored or released into the atmosphere. The aim of this study was to evaluate the traditional silvopastoral systems (TSPS) through quantitative analysis of biomass and soil carbon storage whilst simultaneously qualitatively determining the ecological structure in terms of tree richness and diversity. The study was carried out in Matiguas, a sub-humid tropical region of Nicaragua, on five land use types: shrubland; intervened secondary forest; pasture with high tree density; pasture with low tree density and degraded pasture. Biomass carbon was estimated by allometric equations and soil organic carbon was evaluated at four depths (0–10, 10–20, 20–40 and 40–100 cm). Of the land uses studied, shrubland had the highest diversity. The biomass carbon ranged from 1.9 to 13.2 t C ha−1 for degraded pasture and intervened secondary forest, respectively. The highest soil organic carbon (SOC) storage at 1 m depth was for intervened secondary forest (163 t C ha−1), whereas degraded pastures had the lowest value (76 t C ha−1). Since SOC was the largest pool of total carbon in all cases, it should be evaluated down to a depth of at least 1 m. Increasing tree coverage in degraded and low-tree density pastures can contribute not only to enhance carbon sequestration but also to restore degraded lands in livestock landscapes.

Analysis of land-use/land-cover changes in a livestock landscape dominated by traditional silvopastoral systems: a methodological approach

ABSTRACTRemote sensing, which is a common method to examine land-use/land-cover (LULC) changes, could be useful in the analysis of livestock ecosystem transformations. In the last two decades, before Landsat images were free, developing countries could not afford monitoring through remote sensing because of the high cost of acquiring satellite imagery and commercial software. However, Landsat time series nowadays allows the characterization of changes in vegetation across large areas over time. The aim of this study is to analyse the LULC changes affecting forest frontiers and traditional silvopastoral systems (TSPS) in a representative livestock area of Nicaragua. Nearly cloud-free Landsat scenes – a Landsat 5 Thematic Mapper (TM) scene from 1986 and a Landsat 8 Operational Land Imager (OLI) scene from 2015 – have been the data sets used in the study. A process chain following a four-step definition of the remote-sensing process was conceptually developed and implemented based onfree open source software components and by applying the random forest (RF) algorithm. A conceptual LULC classification scheme representing TSPS was developed. Although the imagery shows a heterogeneous surface cover and mixed pixels, it is possible to achieve promising classification results with the RF algorithm with out-of-the-bag (OOB) errors below 13% for both images along with an overall accuracy level of 85.9% for the 2015 subset and 85.2% for the 1986 subset. The classification shows that from 1986 to 2015 (29 years) the intervened secondary forest (ISF) increased 2.6 times, whereas the degraded pastures decreased by 34.5%. The livestock landscape in Matiguás is in a state of constant transformation, but the main changes head towards the positive direction of tree-cover recovery and an increased number of areas of natural regeneration.

Traditional uses of dispersed trees in the pastures of the mountainous region of Tabasco, Mexico

The rapid deforestation in the state of Tabasco due to extensive livestock farming has resulted in the decrease of the original forest cover. Only 4% of the original vegetation remains and that vegetation is concentrated in the mountainous regions of the state. This destructive process continues due to support by the current government livestock policies. Under these circumstances, the traditional silvopastoral systems of dispersed trees can present an option for reversing and mitigating deforestation practices. The objective of this study was to generate information on the tree species common to silvopastoral systems of dispersed trees in the pastures for two mountainous areas in Tabasco. In the study, 64 tree species, representing 26 plant families were identified. All species were characterized as multipurpose, with at least three reported uses and a maximum of seven for each species. In total, nine categories of local uses were identified for the trees. The main category of use was fuel (firewood), followed by timber and shade for the livestock. Although leguminous species (Fabaceae) were dominant, these species were utilized for uses other than the provision of fodder. Since 12 of the total species identified were recognized as sources of food for animals; the assumption that livestock farmers do not recognize the utility of these species for improving production yields is apparent. The results suggest that there is potential need to expand research and offer further education on the subject in Tabasco.

Viabilidad económica y financiera de sistemas silvopastoriles con Jatropha curcas L. en Manabí, Ecuador

Objetivo. Evaluar la viabilidad económica y financiera de los sistemas silvopastoriles tradicionales para la producción de Biocombustibles como aporte a la sostenibilidad del proyecto “Piñón para Galápagos”. Materiales y Métodos. Se llevaron a cabo encuestas a 450 pequeños productores ganaderos de 10 cantones de la provincia de Manabí con la finalidad de colectar información agronómica, manejo, costos implicados en establecimiento y producción de los sistemas silvopastoriles vigentes de Piñón (Jatropha curcas L.)/Saboya (Megathyrsus maximus). Para recopilar datos de producción del Piñón establecido en cercas vivas de Piñón INIAP CP041 e igualmente se registró la producción de sistemas en 10 sitios, desde el año 2009. Con estos datos se calcularon los siguientes indicadores financieros radio beneficio/costo (B/C), valor actual neto (VAN), tasa interna de retorno (TIR) y valor de expectativa de la tierra (VET). Resultados. El estudio mostró una disminución de la producción del Piñón con el transcurso del tiempo. El sistema silvopastoril mejorado con Piñón INIAP CP041 mostró B/C 1.07, VAN de USD$ 404.11, VET USD$ 970.23 y TIR de 18%. Seguido del sistema silvopastoril con Piñón local con un B/C 1.06, VAN de USD$ 363.66, VET USD$ 873.10 y TIR de 17% y finalmente sistema silvopastoril sin cosecha del Piñón con un B/C 1.05, VAN de USD$ 285.72, VET USD$ 685.99 y TIR de 15%. Conclusiones. La alternativa de producción de biocombustibles con sistemas silvopastoriles Piñón (INIAP CP041)/Saboya en Manabí es el sistema de mayor rentabilidad y no competiría por superficies de cultivo para la producción de alimentos, sin afectar a la seguridad alimentaria.

Livestock vs. wild ungulate management in the conservation of Mediterranean dehesas: Implications for oak regeneration

Dehesas are traditional silvo-pastoral systems with scattered oak trees that maintain considerably high biodiversity. Over the last five decades, dehesas have undergone significant management changes, causing a reduction in oak recruitment that threatens their long-term persistence. Here we examine oak regeneration in Mediterranean dehesas of Central Spain under three distinct and representative management regimes for more than 30years: (1) traditional management of extensive sheep rearing; (2) high commercially-competitive management with extensive cattle grazing, and (3) wildlife grazing, mostly by deer. We found that cattle-grazed dehesas sustained a very low density of young oaks (0.05 young plants per 4m2), one third and one fifth of that found in sheep and wildlife areas, respectively. We also found differences in young oak densities depending on plant growth stage, revealing that saplings (late-stage regeneration), but not seedlings, were more abundant under traditional sheep management. Overall, the probability of herbivory damage was higher in areas with cattle (0.85 probability) than in areas with sheep (0.68) and wildlife (0.30). Cattle areas presented, by far, the highest intensity of herbivory, with 63% of the plants showing very high browsing levels (>70% of the biomass damaged). For all management regimes, shrubs were important microhabitat (nurse plants) for seedlings but not for saplings or oak bushes. Our results suggest that conservation practices should include promotion of traditional sheep rearing, reduction of cattle stocking rates, protection of saplings and oak bushes, rotational grazing and preservation of some shrubs. We conclude that agriculture policies that favor traditional sheep rearing and sustainable wildlife populations can promote the conservation of these valuable systems.

Silvopastoral systems with traditional management in southeastern Mexico: a prototype of livestock agroforestry for cleaner production

Abstract Silvopastoral systems are a prototype of agroforestry with a livestock component, which may be characterized as cleaner production as they provide a variety of goods and services to society; one of their functions is to help adapt to and mitigate climate change. In this article, traditional silvopastoral systems with cattle are characterized, and 35 pastures with silvopastoral management in communities of the Lower Grijalva hydrographic region of Chiapas and Tabasco in Southeastern Mexico are evaluated. This article discusses the general context as well as technical and economic aspects of the cattle raising units (CRU). The high frequency (71%) of land use conversion from maize fields to pastures demonstrates that a significant process of increased establishment of cattle raising is under way. Pastures have an average age of 17.9 years, soils are of medium to high quality, and the dominant herbaceous species are grasses. Scattered trees (ST) in pastures are remnants of the original vegetation which has largely disappeared due to change in land use, with 53 species belonging to 24 botanical families and an average density of 12.3 trees ha−1. In living fences (LF), 32 tree species belonging to 18 botanical families were found, with an average density of 45.8 trees per 100 linear m. It is estimated that on average, one hectare of pasture with a dominance of Cynodon plectostachyus grass (13.10 Mg C ha−1) surrounded by a living fence (7.28 Mg C ha−1) and containing scattered trees (3.00 Mg C ha−1) has a total accumulation of 23.38 Mg C ha−1. Finally, provision of several environmental services, levels of production or yields, and animal products of the CRU with treeless pastures and with two types of silvopastoral systems are analyzed. In order to be considered a form of sustainable development, traditional silvopastoral systems must gradually be transformed into intensive silvopastoral systems. This requires the commitment and co-responsibility of all social actors involved in order to plan community-based, municipal, state-wide, and national policy related to agroforestry with an animal component.

Acacia woodlots, cattle and dung beetles (Coleoptera: Scarabaeinae) in a Mexican silvopastoral landscape

In landscapes where tropical dry forest was once the dominant vegetation type, traditional silvopastoral systems generate a range of natural and semi-natural habitats, namely fragments of secondary forest and fallow land in various stages of succession; essentially Acacia woodlots. This level of heterogeneity seems to favor the arrival and persistence of a large number of Scarabaeinae species. Changes in dung and carrion beetle assemblages were assessed in a silvopastoral landscape in Chiapas, Mexico by intensive sampling using baited pitfall traps. Total species richness decreased from late successional habitats to early successional habitats and average abundance per site was higher in the intermediate successional stages. The silvopastoral system studied is very dynamic; its components may remain constant or change over time, depending on management. These changing conditions lead to a variable local species richness and allow the permeability of certain species within the landscape. There was high species turnover among successional habitats, generating a gamma diversity similar to that of tropical dry forest landscapes and 2-fold higher than the highest recorded alpha diversity value. Silvopastoral systems can buffer the adverse effects of rapid expansion of open areas and the consequent reduction of tropical dry forest area generated by technified conventional systems.

Agroforestry research and practice in Sri Lanka

A review of agroforestry research and practice in Sri Lanka is provided with emphasis on traditional systems, plantation intercropping, silvopastoral systems, fertility improvement and community approaches. Comments are presented on the potentials and difficulties of each technology along with recommendations for further research and training. Some information on components of a number of agroforestry systems has been collected during the last 8 years. A brief account of the results is presented together with comments on current agroforestry practices.