Correlation between species composition and soil properties in the pastures of Plana de Vic (Catalonia, Spain)

The correlation between the species composition of pasture communities and soil properties in Plana de Vic has been studied using two multivariate methods, Correspondence Analysis (CA) for the vegetation data and Principal Component Analysis (PCA) for the soil data. To analyse the pastures, we took 144 vegetation relevés (comprising 201 species) that have been classified into 10 phytocoenological communities elsewhere. Most of these communities are almost entirely built up by perennials, ranging from xerophilous, clearly Mediterranean, to mesophilous, related to medium-European pastures, but a few occurring in shallow soils are dominated by therophytes. As for the soil properties, we analysed texture, pH, depth, bulk density, organic matter, C/N ratio and the carbonates content of 25 samples, correspondingto representative relevés of the communities studied.

Phenological patterns in Mediterranean pastures and scrubs of Catalonia

On the basis of two parallel data sets refering to phenological events in open scrubs and pastures at two sites (Balaguer and Vic), the authors present a comprehensive report of the phenology of these Mediterranean communities. Four main phenophases (vegetative growth, flowering, fruiting and resting) were recorded monthly in 11 communities over 15 months. The results allow comparisons to be drawn between localities and communities, both at community and species levels, and to consider the effects of contemporary climatic data. This yielded useful information on general trends and on the particular responses of each community type to their corresponding constraints.

Multiscale assessment of plant diversity in wooded pastures of the Jura mountains

Résumé La diminution de la biodiversité, à toutes les échelles spatiales et sur l'ensemble de la planète, compte parmi les problèmes les plus préoccupants de notre époque. En terme de conservation, il est aujourd'hui primordial de mieux comprendre les mécanismes qui créent et maintiennent la biodiversité dans les écosystèmes naturels ou anthropiques. La présente étude a pour principal objectif d'améliorer notre compréhension des patrons de biodiversité végétale et des mécanismes sous jacents, dans un écosystème complexe, riche en espèces et à forte valeur patrimoniale, les pâturages boisés jurassiens. Structure et échelle spatiales sont progressivement reconnues comme des dimensions incontournables dans l'étude des patrons de biodiversité. De plus, ces deux éléments jouent un rôle central dans plusieurs théories écologiques. Toutefois, peu d'hypothèses issues de simulations ou d'études théoriques concernant le lien entre structure spatiale du paysage et biodiversité ont été testées de façon empirique. De même, l'influence des différentes composantes de l'échelle spatiale sur les patrons de biodiversité est méconnue. Cette étude vise donc à tester quelques-unes de ces hypothèses et à explorer les patrons spatiaux de biodiversité dans un contexte multi-échelle, pour différentes mesures de biodiversité (richesse et composition en espèces) à l'aide de données de terrain. Ces données ont été collectées selon un plan d'échantillonnage hiérarchique. Dans un premier temps, nous avons testé l'hypothèse élémentaire selon laquelle la richesse spécifique (le nombre d'espèces sur une surface donnée) est liée à l'hétérogénéité environnementale quelque soit l'échelle. Nous avons décomposé l'hétérogénéité environnementale en deux parties, la variabilité des conditions environnementales et sa configuration spatiale. Nous avons montré que, en général, la richesse spécifique augmentait avec l'hétérogénéité de l'environnement : elle augmentait avec le nombre de types d'habitats et diminuait avec l'agrégation spatiale de ces habitats. Ces effets ont été observés à toutes les échelles mais leur nature variait en fonction de l'échelle, suggérant une modification des mécanismes. Dans un deuxième temps, la structure spatiale de la composition en espèces a été décomposée en relation avec 20 variables environnementales et 11 traits d'espèces. Nous avons utilisé la technique de partition de la variation et un descripteur spatial, récemment développé, donnant accès à une large gamme d'échelles spatiales. Nos résultats ont montré que la structure spatiale de la composition en espèces végétales était principalement liée à la topographie, aux échelles les plus grossières, et à la disponibilité en lumière, aux échelles les plus fines. La fraction non-environnementale de la variation spatiale de la composition spécifique avait une relation complexe avec plusieurs traits d'espèces suggérant un lien avec des processus biologiques tels que la dispersion, dépendant de l'échelle spatiale. Dans un dernier temps, nous avons testé, à plusieurs échelles spatiales, les relations entre trois composantes de la biodiversité : la richesse spécifique totale d'un échantillon (diversité gamma), la richesse spécifique moyenne (diversité alpha), mesurée sur des sous-échantillons, et les différences de composition spécifique entre les sous-échantillons (diversité beta). Les relations deux à deux entre les diversités alpha, beta et gamma ne suivaient pas les relations attendues, tout du moins à certaines échelles spatiales. Plusieurs de ces relations étaient fortement dépendantes de l'échelle. Nos résultats ont mis en évidence l'importance du rapport d'échelle (rapport entre la taille de l'échantillon et du sous-échantillon) lors de l'étude des patrons spatiaux de biodiversité. Ainsi, cette étude offre un nouvel aperçu des patrons spatiaux de biodiversité végétale et des mécanismes potentiels permettant la coexistence des espèces. Nos résultats suggèrent que les patrons de biodiversité ne peuvent être expliqués par une seule théorie, mais plutôt par une combinaison de théories. Ils ont également mis en évidence le rôle essentiel joué par la structure spatiale dans la détermination de la biodiversité, quelque soit le composant de la biodiversité considéré. Enfin, cette étude souligne l'importance de prendre en compte plusieurs échelles spatiales et différents constituants de l'échelle spatiale pour toute étude relative à la diversité spécifique. Abstract The world-wide loss of biodiversity at all scales has become a matter of urgent concern, and improving our understanding of local drivers of biodiversity in natural and anthropogenic ecosystems is now crucial for conservation. The main objective of this study was to further our comprehension of the driving forces controlling biodiversity patterns in a complex and diverse ecosystem of high conservation value, wooded pastures. Spatial pattern and scale are central to several ecological theories, and it is increasingly recognized that they must be taken -into consideration when studying biodiversity patterns. However, few hypotheses developed from simulations or theoretical studies have been tested using field data, and the evolution of biodiversity patterns with different scale components remains largely unknown. We test several such hypotheses and explore spatial patterns of biodiversity in a multi-scale context and using different measures of biodiversity (species richness and composition), with field data. Data were collected using a hierarchical sampling design. We first tested the simple hypothesis that species richness, the number of species in a given area, is related to environmental heterogeneity at all scales. We decomposed environmental heterogeneity into two parts: the variability of environmental conditions and its spatial configuration. We showed that species richness generally increased with environmental heterogeneity: species richness increased with increasing number of habitat types and with decreasing spatial aggregation of those habitats. Effects occurred at all scales but the nature of the effect changed with scale, suggesting a change in underlying mechanisms. We then decomposed the spatial structure of species composition in relation to environmental variables and species traits using variation partitioning and a recently developed spatial descriptor, allowing us to capture a wide range of spatial scales. We showed that the spatial structure of plant species composition was related to topography at the coarsest scales and insolation at finer scales. The non-environmental fraction of the spatial variation in species composition had a complex relationship with several species traits, suggesting a scale-dependent link to biological processes, particularly dispersal. Finally, we tested, at different spatial scales, the relationships between different components of biodiversity: total sample species richness (gamma diversity), mean species .richness (alpha diversity), measured in nested subsamples, and differences in species composition between subsamples (beta diversity). The pairwise relationships between alpha, beta and gamma diversity did not follow the expected patterns, at least at certain scales. Our result indicated a strong scale-dependency of several relationships, and highlighted the importance of the scale ratio when studying biodiversity patterns. Thus, our results bring new insights on the spatial patterns of biodiversity and the possible mechanisms allowing species coexistence. They suggest that biodiversity patterns cannot be explained by any single theory proposed in the literature, but a combination of theories is sufficient. Spatial structure plays a crucial role for all components of biodiversity. Results emphasize the importance of considering multiple spatial scales and multiple scale components when studying species diversity.

Effects of rotation period on biomass production and atmospheric CO‚́‚ emissions from broadleaved stands growing on abandoned farmland

Abstract

Soil biological attributes in pastures of different ages in a crop-livestock integrated system

The objective of this work was to evaluate the effect of the pasture (Urochloa brizantha) component age on soil biological properties, in a crop-livestock integrated system. The experiment was carried out in a Brazilian savannah (Cerrado) area with 92 ha, divided into six pens of approximately 15 ha. Each pen represented a different stage of the pasture component: formation, P0; one year, P1; two years, P2; three years, P3; and final with 3.5 years, Pf. Samples were taken in the 0-10 cm soil depth. The soil biological parameters - microbial biomass carbon (MBC), microbial biomass respiration (C-CO2), metabolic quotient (qCO2), microbial quotient (q mic), and total organic carbon (TOC) - were evaluated and compared among different stages of the pasture, and between an adjacent area under native Cerrado and another area under degraded pasture (PCD). The MBC, q mic and TOC increased and qCO2 reduced under the different pasture stages. Compared to PCD, the pasture stages had higher MBC, q mic and TOC, and lower qCO2. The crop-livestock integrated system improved soil microbiological parameters and immobilized carbon in the soil in comparison to the degraded pasture.

Soil organic matter in fire-affected pastures and in an Araucaria forest in South-Brazilian Leptosols

The objective of this work was to evaluate the distribution pattern and composition of soil organic matter (SOM) and its physical pools of Leptosols periodically affected by fire over the last 100 years in South Brazil. Soil samples at 0-5, 5-10, and 10-15 cm depths were collected from the following environments: native pasture without burning in the last year and grazed with 0.5 livestock per hectare per year (1NB); native pasture without burning in the last 23 years and grazed with 2.0 livestock per hectare per year (23NB); and an Araucaria forest (AF). Physical fractionation was performed with the 0-5 and 5-10 cm soil layers. Soil C and N stocks were determined in the three depths and in the physical pools, and organic matter was characterized by infrared spectroscopy and thermogravimetry. The largest C stocks in all depths and physical pools were found under the AF. The 23NB environment showed the lowest soil C and N stocks at the 5-15 cm depth, which was related to the end of burning and to the higher grazing intensity. The SOM of the occluded light fraction showed a greater chemical recalcitrance in 1NB than in 23NB. Annual pasture burning does not affect soil C stocks up to 15 cm of depth.

Publicacions sobre farratges i pastures a Catalunya (1800-2004)

A causa de la ràpida evolució de la tecnologia, una gran quantitat de publicacions sobre pastures i farratges fetes a Catalunya han quedat oblidades. S'aprofita l'oportunitat de participar en el projecte «Tipificación, cartografía y evolución de los pastos españoles (1800-2004)» per posar al dia la revisió bibliogràfica. Amb la nostra recerca s'han trobat 316 articles o llibres sobre cultius farratgers i 159 sobre prats i pastures que en aquest treball es presenten ordenats per cultius.

Publicacions sobre farratges i pastures a Catalunya (1800-2004)

A causa de la ràpida evolució de la tecnologia, una gran quantitat de publicacions sobre pastures i farratges fetes a Catalunya han quedat oblidades. S’aprofita l’oportunitat de participar en el projecte «Tipificación, cartogra- fía y evolución de los pastos españoles (1800-2004)» per posar al dia la revisió bibliogràfica.Amb la nostra recerca s’han trobat 316 articles o llibres sobre cultius farratgers i 159 sobre prats i pastures que en aquest treball es presenten ordenats per cultius.

Estudi de la producció i de la qualitat farratgera de les pastures de la finca dels Cingles de l'Avenc (Tavertet). 2011

A Catalunya, la protecció i gestió de zones d’especial interès natural ha estat majoritàriament realitzada pel conjunt de les administracions públiques. Tot i així, en els últims anys han sorgit un conjunt d’iniciatives privades que a través d’acords de custòdia han passat a tenir un paper actiu en la protecció i gestió d’algunes finques amb un alt valor natural. És el cas de la finca els Cingles de l’Avenc, on s’ha dut a terme aquest treball, en la qual es pretén desenvolupar una activitat ramadera compatible amb la conservació dels valors naturals de la finca. L’objectiu principal d’aquest treball és conèixer la producció i qualitat farratgera dels diferents tipus de pastures que hi ha a la finca, i establir la càrrega ramadera que poden admetre. Aquest estudi ha tingut una durada de 3 anys i en aquest treball es presenten els resultats del 2011 i es fa l’anàlisi dels resultats dels 3 anys (2009, 2010, i 2011). L’estudi s’ha portat a terme en els 4 tipus principals de pastures que hi ha a la finca: joncedes, pastures mesòfiles, prats de dall i pastures sembrades. S’han utilitzat 11 parcel·les permanents excloses de la pastura, establertes l’any 2009, que inclouen la diversitat de tipus i zones de pastura. S’ha realitzat un mostreig de la biomassa mensual, d’abril a novembre, que ha consistit en dallar 4 quadrats de 50 x 50 cm, i s’ha calculat la producció anual. S’ha determinat la qualitat farratgera de l’herba de 4 moments de l’any: maig, juny, juliol i octubre. Després dels tres anys d’estudi hem obtingut que les pastures sembrades i els prats de dall són els més productius (1.067 g/m2.any i 1.005 g/m2.any, respectivament). La producció de les pastures mesòfiles i de les joncedes són més baixes (554 g/m2.any i 291 g/m2.any, respectivament). La qualitat farratgera de les pastures és bona a totes les comunitats, amb valors mitjans de proteïna digerible de 6,63%, de fibra bruta de 29,13%, de lignina de 7,29% i de 0,69 (ENL/1,700) unitats farratgeres. La producció anual global obtinguda a la finca durant aquests tres anys permet suportar una càrrega ramadera admissible d’unes 208 UBG (Unitats de Bestiar Gros. 1 U.B.G equival a 1 vaca a partir de 2 anys).

Soil quality assessment through a multi-approach analysis in soils of abandoned terraced land in NE Spain

The abandonment of agricultural land in mountainous areas has been an outstanding problem along the last century and has captured the attention of scientists, technicians and administrations, for the dramatic consequences sometimes occurred due to soil instability, steep slopes, rainfall regimes and wildfires. Hidromorfological and pedological alterations causing exceptional floods and accelerated erosion processes has therefore been studied, identifying the cause in the loss of landscape heterogeneity. Through the disappearance of agricultural works and drainage maintenance, slope stability has resulted severely affected. The mechanization of agriculture has caused the displacement of vines, olives and corks trees cultivation in terraced areas along the Mediterranean catchment towards more economically suitable areas. On the one hand, land use and management changes have implicated sociological changes as well, transforming areas inhabited by agricultural communities into deserted areas where the colonization of disorganized spontaneous vegetation has buried a valuable rural patrimony. On the other hand, lacking of planning and management of the abandoned areas has produced badlands and infertile soils due to wildfire and high erosion rates strongly degrading the whole ecosystems. In other cases, after land abandonment a process of soil regeneration has been recorded. Investigations have been conducted in a part of NE Spain where extended areas of terraced soils previously cultivated have been abandoned in the last century. The selected environments were semi-abandoned vineyards, semi-abandoned olive groves, abandoned stands of cork trees, abandoned stands of pine trees, scrubland of Cistaceaea, scrubland of Ericaceaea, and pasture. The research work was focused on the study of most relevant physical, chemical and biological soil properties, as well as runoff and erosion under soils with different plant cover to establish the abandonment effect on soil quality, due to the peculiarity and vulnerability of these soils with a much reduced depth. The period of observation was carried out from autumn 2009 to autumn 2010. The sediment concentration of soil erosion under vines was recorded as 34.52 g/l while under pasture it was 4.66 g/l. In addition, the soil under vines showed the least amount of organic matter, which was 12 times lower than all other soil environments. The carbon dioxide (CO2) and total glomalin (TG) ratio to soil organic carbon (SOC) in this soil was 0.11 and 0.31 respectively. However, the soil under pasture contained a higher amount of organic matter and showed that the CO2 and TG ratio to SOC was 0.02 and 0.11 respectively indicating that the soil under pasture better preserves the soil carbon pool. A similar trend was found in the intermediate soils in the sequence of land use change and abandonment. Soil structural stability increased in the two soil fractions investigated (0.25-2.00 mm, 2.0-5.6 mm) especially in those soils that did not undergo periodical perturbations like wildfires. Soil quality indexes were obtained by using relevant physical and chemical soil parameters. Factor analysis carried out to study the relationship between all soil parameters allowed to related variables and environments and identify those areas that better contribute to soil quality towards others that may need more attention to avoid further degradation processes

Estudi de la producció i de la qualitat farratgera de les pastures de la finca dels Cingles de l'Avenc (Tavertet). 2010

El present estudi s’emmarca dins les accions prioritàries del Pla de Gestió de la finca dels Cingles de l’Avenc, que té com a finalitat principal potenciar una explotació ramadera on la conservació dels recursos naturals, la protecció de la diversitat biològica i paisatgística i l’equilibri territorial, siguin els seus objectius fonamentals, garantint la viabilitat econòmica i el manteniment de les activitats agrícoles i ramaderes. L’objectiu principal d’aquest treball és conèixer la producció i la qualitat farratgera dels diferents tipus de comunitats pastorals presents a la finca dels Cingles de l’Avenc, i establir la càrrega ramadera que poden suportar les pastures durant l’any 2010, així com el d’observar la variabilitat d’aquest factors entre els anys 2009 i 2010. L’estudi s’ha portat a terme en les 4 tipologies de comunitats pradenques que hi ha a la finca: joncedes, pastures mesòfiles, prats de dall i pastures sembrades. S’han utilitzat les 11 parcel·les permanents excloses de la pastura, instal·lades l’any anterior (2009), que inclouen la diversitat de tipus i zones de pastura. S’ha realitzat un mostreig de la biomassa mensual, d‘abril a novembre, que ha consistit en dallar 4 quadrats de 50 x 50 cm, i s’ha calculat la producció anual. S’ha determinat la qualitat farratgera de l’herba de 4 moments de l’any: maig, juny, juliol i octubre. I finalment s’ha calculat la capacitat de càrrega de cada tipus pastura i del conjunt de la finca. Les pastures sembrades i els prats de dall són els més productius (961,33 g/m2 any i 876,73 g/m2 any, respectivament). La producció de les pastures mesòfiles i de les joncedes és més baixa (578,24 g/m2 ·any i 211,76 g/m2 any, respectivament). A les pastures de la part baixa s’obtenen en general produccions superiors a les de la part alta. La qualitat farratgera de l’herba és bona a totes les comunitats, amb valors mitjans de: 7,25% de proteïna digerible, 28,22% de fibra bruta, 7,08% de lignina i 0,72 unitats farratgeres(ENL/1,700). La producció anual obtinguda en global de la finca a l’any 2010 és molt semblant a la obtinguda l’any 2009, i permet suportar una càrrega ramadera d’unes 190 UBG (Unitats de Bestiar Gros. 1 U.B.G equival a 1 vaca a partir de 2 anys).

Natural regeneration in abandoned fields following intensive agricultural land use in an Atlantic Forest Island, Brazil

The time required to regrowth a forest in degraded areas depends on how the forest is removed and on the type of land use following removal. Natural regeneration was studied in abandoned old fields after intensive agricultural land use in areas originally covered by Brazilian Atlantic Forests of the Anchieta Island, Brazil in order to understand how plant communities reassemble following human disturbances as well as to determine suitable strategies of forest restoration. The fields were classified into three vegetation types according to the dominant plant species in: 1) Miconia albicans (Sw.) Triana (Melastomataceae) fields, 2) Dicranopteris flexuosa (Schrader) Underw. (Gleicheniaceae) thickets, and 3) Gleichenella pectinata (Willd.) Ching. (Gleicheniaceae) thickets. Both composition and structure of natural regeneration were compared among the three dominant vegetation types by establishing randomly three plots of 1 x 3 m in five sites of the island. A gradient in composition and abundance of species in natural regeneration could be observed along vegetation types from Dicranopteris fern thickets to Miconia fields. The gradient did not accurately follow the pattern of spatial distribution of the three dominant vegetation types in the island regarding their proximity of the remnant forests. A complex association of biotic and abiotic factors seems to be affecting the seedling recruitment and establishment in the study plots. The lowest plant regeneration found in Dicranopteris and Gleichenella thickets suggests that the ferns inhibit the recruitment of woody and herbaceous species. Otherwise, we could not distinguish different patterns of tree regeneration among the three vegetation types. Our results showed that forest recovery following severe anthropogenic disturbances is not direct, predictable or even achievable on its own. Appropriated actions and methods such as fern removal, planting ground covers, and enrichment planting with tree species were suggested in order to restore the natural forest regeneration process in the abandoned old fields.