Análisis de la implementación de un ciclo de mejora docente en la asignatura Ciencia y Tecnología del Medio Ambiente

El presente ciclo de mejora docente (CMD) ha sido realizado en la asignatura Ciencia y Tecnología del Medio Ambiente de 2º curso del Grado de Ingeniería Agrícola (Universidad de Sevilla). Los principales problemas detectados en esta asignatura, en los cursos previos a este CMD, han sido: escasa asistencia a clase, poca o nula asistencia a tutorías y aplazamiento del estudio de los contenidos a los días previos al examen final. Este CMD se ha centrado en las interacciones biológicas entre poblaciones y se ha llevado a cabo en 5 sesiones (4 teóricas y 1 práctica), durante las cuales se planificaron un conjunto de actividades basadas en ejemplos prácticos y dinámicas grupales que potenciaron la reflexión sobre los contenidos por parte de los estudiantes. La experiencia realizada ha sido muy gratificante y los resultados obtenidos indican una valoración muy positiva por parte de los estudiantes por este tipo de metodología docente

Carbon footprint of dairy goat production systems: A comparison of three contrasting grazing levels in the Sierra de Grazalema Natural Park (Southern Spain)

The main objective of this study was to analyze the carbon footprint (CF) of grazing dairy goat systems in a natural park according to their grazing level. A total of 16 representative grazing goat farms in southern Spain were selected and grouped into three farming systems: low productivity grazing farms (LPG), more intensified grazing farms (MIG) and high productivity grazing farms (HPG). Their CF was analyzed, including greenhouse gas emissions and soil C sequestration according to the farms’ grazing level and milk productivity, taking into account different functional units (one kilogram of fat and protein corrected milk (FPCM) and one hectare) and milk correction. Results showed that all variables differed according to the milk correction applied as the values for cow's milk correction were 41% lower than for sheep's milk correction. Total emissions and contributions of soil carbon sequestration differed according to farming system group; LPG farms had higher total emissions than MIG and HPG farms, however total carbon sequestration was lower in the MIG farms than in the LPG and HPG farms. The CF values ranged from 2.36 to 1.76 kg CO2e kg⁻¹ FPCM for sheep's milk correction and from 1.40 to 1.04 kg CO2e kg⁻¹ FPCM for cow's milk correction. No differences were found between farming system groups in either of the two cases but when calculations took hectare of land as a functional unit, the contribution of MIG farms to the CF was 85% higher than LPG and HPG farms. Therefore it is important to take into account the functional unit used to calculate the CF by analyzing this indicator in a broader context, and including carbon sequestration by grazing livestock in the calculation. In order to reduce the CF of this type of system, it is advisable to make appropriate use of the natural resources and to reach an optimum level of milk productivity, high enough for pastoral livestock farming to be viable

Efectividad cualitativa del ganado caprino en la dispersión de especies de frutos secos y carnosos

[ES] mediterráneo: Cistus salviifolius, C. libanotis, Halimum halimifolium H. calycinum, Myrtus communis, Phillyrea angustifolia, Pistacia lentiscus y Rhamnus lycioides. Frutos de estas especies fueron ofrecidos a seis cabras estabuladas individualmente. Tras la ingestión, se procedió a recoger las heces a intervalos de 24 horas. En las heces recuperadas, se determinó el porcentaje de pérdida de semillas (masticación y digestión), distribución de la recuperación de las semillas en el tiempo y la eficacia germinativa tras el paso por el tracto digestivo. Menos del 30% de las semillas ingeridas fueron recuperadas, con diferencias significativas entre las especies. C. salviifolius presentó el mayor porcentaje de recuperación (casi 30%) y P. lentiscus el menor (0%). Esta tasa de recuperación estuvo significativamente relacionada positivamente con la dureza de las semillas. En la mayoría de las especies, la máxima tasa de recuperación se dio entre las 24-72 horas tras la ingestión. El paso por el intestino de las cabras aumentó significativamente la germinación de C. salviifolius, H. halimifolium, H. calycinum y P. angustifolia. Los resultados de este estudio pusieron de manifiesto que el ganado caprino puede favorecer la dispersión de la mayoría de las semillas de especies cistáceas estudiadas e inhibir la dispersión de semillas de frutos carnosos. El conocimiento de los mecanismos de dispersión por ungulados generalistas son aspectos importantes a tener en cuenta en los planes de gestión, restauración y conservación de los ecosistemas Mediterráneos[EN] We evaluated the role of domestic goats as seed dispersers of eight representative Mediterranean shrub species (Cistus salviifolius, C. libanotis, Halimum halimifolium, H. calycinum, Myrtus communis, Phillyrea angustifolia, Pistacia lentiscus and Rhamnus lycioides). Six female goats of similar size and age were fed with fruits of study species. Following fruits ingestion by goats, total faeces were collected at 24-h intervals. The seeds retrieved were tested for germination and viability, along with seeds not eaten by the goats. Less than 30% of the seeds eaten were retrieved from the dung, with significant differences between species. C. salviifolius showing the maximum recovery percentage (30%), and P. lentiscus the minimum (0%). Seed recovery was significantly related to seed hardness. In most species, the maximum amount of seeds recovered occurred 24-72 h after ingestion. The passage through the goat gut significantly increased seed germination in C. salviifolius, H. halimifolium, H. calycinum and P. angustifolia. The results of this study show that goats can potentially favour (Cistaceae) or inhibit (fleshy fruits) seed dispersal of browsed Mediterranean shrub species. Therefore, these results should be considered when developing conservation and restoration plans of natural vegetation in Mediterranean areasPeer reviewe

Endozoochorus seed dispersal by goats: recovery, germinability and emergence of five Mediterranean shrub species

Herbivores can play an important role as seed dispersal vectors, ungulates constituting potential seed dispersal agents of Mediterranean grasses and shrubs. We evaluated the role of domestic goats as seed dispersers of five representative Mediterranean forage shrub species [Cistus albidus L., Phillyrea angustifolia L., Calicotome villosa (Poir.) Link., Rhamnus lycioides L. and Atriplex halimus L.]. Following seed ingestion by goats, total faeces were collected at 24-h intervals for five days. The total number of seeds recovered varied among species, with R. lycioides showing the minimum recovery percentage (1.3%) and C. albidus (35.8%), the maximum. Seed recovery was significantly related to seed hardness and length. In most species, the maximum amount of seeds recovered occurred 48-72 h after ingestion. The passage through the goat gut significantly depressed seed germination in C. albidus, C. villosa and A. halimus; inhibited it in R. lycioides and increased it in P. angustifolia. Seedling emergence was significantly lower in intact dung pellets than in broken-down ones, and both significantly lower than in uneaten seeds (control). The results of this study show that goats can potentially favor or inhibit seed dispersal of browsed Mediterranean shrub species. Therefore, goat grazing could be a potential management tool for expanding target shrub species populations or preventing shrub encroachment in undesired areas

The Contribution of Traditional Meat Goat Farming Systems to Human Wellbeing and Its Importance for the Sustainability of This Livestock Subsector

Traditional meat goat farming systems are characterized by rearing autochthonous breeds and using natural resources through grazing, often within protected natural areas. In a context of reduction of the number of farms, due to the low income derived from the sale of kids, the role of those systems as suppliers of presently non-remunerated ecosystem services becomes more relevant. The objective of this article is to analyze the current situation of those systems, focusing on their connection with human wellbeing, and to formulate proposals that can contribute to guaranteeing their profitability and continuity. A technical-economic and environmental study of a sample of farms and an analysis of the limiting factors affecting the subsector were carried out. As a result, a set of multifactorial problems was identified, with the lack of acknowledgement and remuneration of some services—mainly environmental and cultural—provided by those systems and the low selling price of kids standing as the main threats. The consideration of meat goat farms as “producers of meat of high functional quality and providers of ecosystem services”, which should be properly quantified and remunerated, would contribute to their preservation and guarantee the provision of benefits associated with the activity

Efecto del pastoreo caprino y vacuno en pastos oligotrofos del Espacio Natural de Doñana

Se estudia el efecto del pastoreo sobre la composición del pasto, la frecuencia de plantas y suelo (descubierto y/o cubierto de acículas de pino), la producción, la biomasa acumulada y el tamaño del banco de semillas, en tres tipos de vegetación (alcornocal adehesado, pinar adehesado y pinar con sotobosque de matorral y claros herbáceos) en una formación forestal representativa de la provincia de Huelva. Los resultados indican un aumento significativo de suelo descubierto, por efecto del pastoreo, tanto en el pinar adehesado como en los claros de pinar pero no en el alcornocal adehesado. El pastoreo también redujo significativamente la frecuencia de herbáceas en todas las unidades de vegetación y produjo una tendencia a la reducción de acículas de pino. La composición del pasto varió considerablemente entre el alcornocal adehesado, mucho más productivo (327±20 gMS .m-2 .año-1) y las otras unidades, mucho menos productivas (43 a 97 gMS .m-2 .año-1) pero no hubo diferencias en composición entre el pinar adehesado y los claros de pinar. El banco de semillas se redujo significativamente por pastoreo en el alcornocal y en el pinar adehesado, pero no en los claros del pinar

Effect of different digestates derived from anaerobic co-digestion of Olive Mill Solid Waste (OMSW) and various microalgae as fertilizers for the cultivation of ryegrass

Aims The aim of this work was to evaluate the fertilizing effect of three anaerobic co-digestates on the growth of the herbaceous plant Lolium rigidum. Methods Nine treatments, combining different nutritional solutions (organic and inorganic) and number of fertilizations (one or two) were evaluated. Organic nutritive solution: plants grown with different olive mill solid waste (OMSW) -microalgae co-digestates: 75% OMSW-25% Raphidocelis subcapitata, volatile solids (VS) basis (OMSW-Rs); 50% OMSW- 50% Chlamydomonas Reinhardtii, VS basis (OMSW-Chl); and 75% OMSW-25% Secenedesmus quadricauda, VS basis (OMSW-Sq). Inorganic nutritive solution (INS): plants grown with inorganic Hoagland nutrient solution at 50%. After 60 days of experimentation, biometric and nutritional characteristics and photosynthetic activity were measured. Results The results showed a favourable growth, development and nutritional quality of L. rigidum plants when digestates obtained from the anaerobic co-digestion of OMSW-microalgae are used as organic nutritional solutions as opposed to INS ones. The highest total biomass of L. rigidum was obtained with the treatments that involved two fertilizations. No inhibition due to excess nutrients was observed. A higher root/shoot ratio was achieved with the digestates of OMSW-Rs and OMSW-Ch as compared to that obtained with OMSW-Sq (F = 17.23 p ≤ 0.001). The nitrogen shoot biomass obtained after the organic treatments with the above-mentioned co-digestates was higher than that obtained after the inorganic treatment. Net photosynthesis rates did not present differences in the co-digestates treatments, being equal or superior to the INS treatments. Conclusions The use of the anaerobic co-digestates from OMSW-microalgae can be considered a viable and promising alternative to inorganic fertilization

El papel del ganado doméstico autóctono en la mejora de pastos herbáceos

En la región Mediterránea la dispersión endozoócora de semillas es una alternativa potencial para recuperar pastizales y matorrales degradados o abandonados. Los objetivos de este estudio fueron determinar si el paso a través del sistema digestivo de cabras afectó la recuperación de semillas, la germinación y emergencia de plántulas de tres leguminosas herbáceas comunes del área Mediterránea (Ornithopus compressus L., Medicago polymorpha L. y Melilotus officinalis L. Pall.). El porcentaje total de recuperación de semillas osciló entre 0,31% y 6,80%. En todas las especies las semillas recuperadas tras la ingestión presentaron una germinación significativa menor que las semillas control, con porcentajes de germinación de 26,7% a 50,0%. La emergencia de plántulas fue menor en las heces intactas que en las disgregadas. No se encontró emergencia de plántulas de las semillas de O. compressus para ninguno de los tratamientos ni tiempos de muestreo. Aunque los porcentajes de recuperación de semillas, la germinación y emergencia de plántulas fueron bajos en términos absolutos, se concluye que las semillas de M. polymorpha y M. officinalis podrían establecerse desde el estiércol y representar una alternativa potencial para recuperar áreas de pastoreo degradadas o abandonadas

Endozoochory by goats of two invasive weeds with contrasted propagule traits

Invasive plants have very important ecological and socioeconomic impacts. Producing and dispersing many viable seeds are key plant functional traits for invaders. Ungulate grazing plays an important role in the endozoochorous seed dispersal within grasslands and rangelands. Grazing can be applied as a practical and economical control method for plant invasions. We analyzed the effects of seed passage through the goat digestive system on the germination and viability for Sorghum halepense and Malva parviflora, common invasive species with contrasted propagules and seed traits. Both studied species produced seeds able to survive, in a small percentages (c. 0.80-1.70%), after being eaten by goats. Most of the seeds (c. 40-55%) of both species were retrieved between 24-48 h after ingestion. Goat passage provoked a decrease (> 60%) in the germination percentage and seed viability of S. halepense that was higher with longer gut retention times. In M. parviflora, the goat gut passage did not break its primary physical dormancy, since no retrieved seed germinated with similar viability as the uneaten seeds (c. 90%). In view of our results, goat grazing can be applied as a useful method to control S. halepense and M. parviflora invasions. Goats should be kept in corrals for at least 4 days after grazing to prevent transferring viable seeds to uninfected areas.Deanship of Scientific Research King Khalid University R.G.P.1/210/4