Jardin botanique | EPFL Graph Search

thumb|upright=1.5|Jardin botanique de Curitiba (Brésil) thumb|upright=1.5|Jardin botanique de Buenos Aires (Argentine) Un jardin botanique est un territoire aménagé par une institution publique, privée, ou associative (parfois à gestion mixte) qui a pour but la présentation d'espèces et variétés végétales. Les nombreuses espèces et variétés de plantes sauvages et/ou horticoles présentes sont strictement identifiées et réunies en collections. Elles sont cultivées et étudiées pour satisfaire quatre objectifs principaux : la conservation, la recherche scientifique, l'éducation et l’enseignement, tout en restant compatible avec le tourisme. Mondialement, les plus importants jardins botaniques, en superficie et en taille de la collection, sont les Jardins botaniques royaux de Kew suivis par le Jardin botanique de Montréal. Historique Histoire des jardins botaniques vignette| Le jardin botanique de Padoue (Italie), fondé en 1545, le plus ancien encore existant (gravure du ). v

Evaporation over a Heterogeneous Mixed Savanna-Agricultural Catchment using a Distributed Wireless Sensor Network

Natalie Claire Ceperley

Small scale rain fed agriculture is the primary livelihood for a large part of the population of Burkina Faso. Regional climate change means that this population is becoming increasingly vulnerable. Additionally, as natural savanna is converted for agriculture, hydrological systems are observed to become less stable as infiltration is decreased and rapid runoff is increased to the detriment of crop productivity, downstream populations and local water sources. The majority of the Singou River Basin, located in South East Burkina Faso is managed by hunting reserves, geared to maintaining high populations of wild game; however, residents surrounding the protected areas have been forced to intensify agriculture that has resulted in soil degradation as well as increases in the frequency and severity of flooding and droughts. Agroforestry, or planting trees in cultivated fields, has been proposed as a solution to help buffer these negative consequences, however the specific hydrologic behavior of the watershed land cover is unknown. We have installed a distributed sensor network of 17 Sensorscope wireless meteorological stations. These stations are dispersed across cultivated rice and millet fields, natural savanna, fallow fields, and around agroforestry fields. Sensorscope routes data through the network of stations to be delivered by a GPRS connection to a main server. This multi hop network allows data to be gathered over a large area and quickly adapts to changes in station performance. Data are available in real time via a website that can be accessed by a mobile phone. The stations are powered autonomously by small photovoltaic panels. This deployment is the first time that these meteorological stations have been used on the African continent. Initial calibration with measures from 2 eddy covariance stations allows us to calculate the energy balance at each of the Sensorscope stations. Thus, we can observe variation in evaporation over the various land cover in the watershed. This research will both contribute to scientific understanding of West African vegetation and inform local reforestation and agricultural management. Concurrent to this scientific research, the community is improving natural resource management efforts including reforestation, a botanical garden and environmental education. Our hope is that the results of our evaporation modeling will inform local farmers and thus help improve their adaption to changing weather patterns and land cover.

2010

Cutover peatland regeneration assessment using organic matter and microbial indicators (bacteria and testate amoebae)

Alexandre Buttler, Edward Mitchell

Cutover peatlands cover large surfaces of high potential value for biodiversity and carbon sequestration function if successfully restored but the evaluation of restoration success is not straighforward. We assessed the bioindicator value of organic matter (OM), testate amoebae (protozoa) and bacteria in peat from two regeneration stages and a reference site of a cutover bog. 2. Contrasting biochemical signatures of peat OM were observed along the regenerating profiles allowing clear differentiation between the newly regenerated peat and the old peat. Where peat macrofossils were absent sugar biomarkers allowed to infer peat botanical origin and OM alteration. 3. Over the succession, the OM composition of the new peat differed: peat from the recent stage was more dominated by Sphagnum-derived tissues and was characterised by lesser carbohydrate preservation and higher bacterial biomass than the advanced regeneration stage. 4. Surface testate amoeba communities also changed from the recent to the advanced stages of regeneration indicating a shift from wet and moderately acidic conditions to drier and more acidic conditions. Over this regeneration sequence (i) biomass and average size of species declined but were higher in the unexploited site (ii) species richness and diversity increased but density declined. 5. Synthesis and applications. Although the secondary succession in the cutover bog leads to an ecosystem similar to that of the reference site in terms of surface vegetation, OM and testate amoebae continue to reflect disturbances associated with peat harvesting. Nevertheless, the described dynamics of both microbial and biochemical variables over the succession showed similarities between the advanced stage and the reference: a higher testate amoeba diversity is associated with better carbohydrate preservation and a more heterogeneous botanical composition of the peat. The quantitative inference of water table depth and pH based on testate amoebae indicators represents an alternative to labour-intensive repeated measurements in the field. Botanical and biochemical composition of peat OM provides additional information on past anthropogenic perturbations of the bog and can be used for restoration monitoring. The combination of several indicators therefore provides a more complete assessment of ecological conditions which could be valuable for the management of cutover peatlands.

2008

Evaporation over a Heterogeneous Mixed Savanna-Agricultural Catchment using a Distributed Wireless Sensor Network

Natalie Claire Ceperley

2010

Cutover peatland regeneration assessment using organic matter and microbial indicators (bacteria and testate amoebae)

Alexandre Buttler, Edward Mitchell

Cutover peatlands cover large surfaces of high potential value for biodiversity and carbon sequestration function if successfully restored but the evaluation of restoration success is not straighforward. We assessed the bioindicator value of organic matter (OM), testate amoebae (protozoa) and bacteria in peat from two regeneration stages and a reference site of a cutover bog. 2. Contrasting biochemical signatures of peat OM were observed along the regenerating profiles allowing clear differentiation between the newly regenerated peat and the old peat. Where peat macrofossils were absent sugar biomarkers allowed to infer peat botanical origin and OM alteration. 3. Over the succession, the OM composition of the new peat differed: peat from the recent stage was more dominated by Sphagnum-derived tissues and was characterised by lesser carbohydrate preservation and higher bacterial biomass than the advanced regeneration stage. 4. Surface testate amoeba communities also changed from the recent to the advanced stages of regeneration indicating a shift from wet and moderately acidic conditions to drier and more acidic conditions. Over this regeneration sequence (i) biomass and average size of species declined but were higher in the unexploited site (ii) species richness and diversity increased but density declined. 5. Synthesis and applications. Although the secondary succession in the cutover bog leads to an ecosystem similar to that of the reference site in terms of surface vegetation, OM and testate amoebae continue to reflect disturbances associated with peat harvesting. Nevertheless, the described dynamics of both microbial and biochemical variables over the succession showed similarities between the advanced stage and the reference: a higher testate amoeba diversity is associated with better carbohydrate preservation and a more heterogeneous botanical composition of the peat. The quantitative inference of water table depth and pH based on testate amoebae indicators represents an alternative to labour-intensive repeated measurements in the field. Botanical and biochemical composition of peat OM provides additional information on past anthropogenic perturbations of the bog and can be used for restoration monitoring. The combination of several indicators therefore provides a more complete assessment of ecological conditions which could be valuable for the management of cutover peatlands.

2008