Final Report Summary - CAPACITI (Carbon dynamics in Pyrenean grasslands: a first-time assessment with ecosystem fluxes, isotopic marking, and plant guilds)
The role of terrestrial ecosystems in the course of global change is paramount, and central to this is the feedback between carbon-cycle and climate. Terrestrial ecosystems are the valve that connects the atmosphere with huge reservoirs of carbon: plant biomass and soil organic carbon. Whether this carbon is sequestered in the land or released to the atmosphere depends on the balance between gains and losses of carbon in terrestrial ecosystems. This exchange is mediated by the biological processes that cycle the C in the plant-soil systems.
The importance of grasslands in the global C cycle lies in their large existing soil carbon stocks and their future carbon sequestration potential. Whether a particular grassland acts as sink or source of CO2 depends on management history and intensity. Estimates of the overall contribution remain, however, uncertain, due to the variety of grassland types that can be considered, which extend from semi-natural to intensively managed ecosystems along a wide geographical range. The particular case of mountain pastures has been poorly explored. The study of mountain environments has the added urgency of their intrinsic fragility. Mountains are particularly vulnerable to climate change; they are expected to be the first ones hit by climate change.
Both natural and antrophogenic drivers are changing through climate and land-use transformation. Vegetation responds to these changes. Grasslands are dynamic communities, whose adaptation to changing conditions is signalled by a change in community composition. Such changes in community composition will have direct impact in ecosystem functioning (long-term C and N accumulation, fine root processes, productivity, soil respiration).
With the motivation of describing, understanding and assessing the role of vegetation composition in the carbon cycle, the project CAPACITI has been following the annual course of environmental and ecological events at semi-natural mountain pastures at the Pyrenees. In other words, this project, studied the annual carbon dynamics of semi-natural mountain pastures in relation to the plant-soil system processes which are expected to modulate the C balance of the ecosystem.
Different types of plants follow different functional strategies for optimization of the resources, and they also present –along the year- different patterns of change in their capacities such as photosynthetic fixation, belowground C allocation, and C loss via respiration. Species can be grouped into functional types that represent these plant functions. Life-forms (grasses, sedges, legumes, forbs, woody, mosses) are indicators of plant functional types and were chosen as background for the trait-base approach which is transversal to all activities of the study.
The studied pastures were located in the south west Pyrenees at montane and sub-alpine altitudes, namely: La Bertolina, Alinyà, and Castellar at 1300, 1700, and 1900 m a.s.l. respectively. In addition, there was one low-land pasture at the North-face, Lannemezan also available to the study (see Table 1 for details attached).
The project has achieved two main objectives organized around two major methodological approaches:
• Monitoring of the dynamics of the annual net ecosystem CO2 exchange and determine its main controlling factors. A specific aim was to determine whether the seasonal distribution of plant functional types can be detected in the short-term ecosystem exchange and what role it plays. This was achieved with continuous measurements of meteorological and micrometeorological variables combined with a thorough description of the vegetation.
• Monitoring of the variation in plant-soil system processes along the growing season and between plant guilds. The project used the measurement of natural abundance of isotopes at different compartment of the system to detect whether different temporal patterns arise between different functional types.
The project proposed quite intense data gathering involving frequent and comprehensive field sampling. The automatic continuous measurements provided by the micrometeorological station were in the first year of implementation and required as well intense follow-up. Populating the proposed database has been the main activity carried out during the project. Preliminary analyses on the data show that:
There is a clear seasonal dynamics in all studied parameters
There is difference between plant functional types in most of the studied parameters. However, the detail of the data invites to have a critical look at the division of the functional types
The relation between the ecosystem-scale fluxes and the ecosystem-survey data is under analysis beyond the time-frame of the project.
The implementation of management styles that favour the carbon uptake can lead to net accumulation in grasslands and pastures, thereby sequestering atmospheric carbon. Mitigation of CO2 emissions (and green house gas in general) is envisioned as a relevant ecosystem service and involves an added-value to the agro-pastoral systems that can provide such. Therefore, in addition of achieving the understanding about the processes behind the carbon dynamics, there is also need to determine locally whether we are tackling systems with a tendency to lose or capture carbon. The results of projects like CAPACITI should provide relevant information to stakeholder such as Climate Change Agencies and Regulating Bodies for pasture management, as well as land-owners themselves.
Details on the stations, project and group and host institute at http://fluxpyr.eu/eng/index.htm , http://ecofun.ctfc.cat and http://www.ctfc.cat/
The importance of grasslands in the global C cycle lies in their large existing soil carbon stocks and their future carbon sequestration potential. Whether a particular grassland acts as sink or source of CO2 depends on management history and intensity. Estimates of the overall contribution remain, however, uncertain, due to the variety of grassland types that can be considered, which extend from semi-natural to intensively managed ecosystems along a wide geographical range. The particular case of mountain pastures has been poorly explored. The study of mountain environments has the added urgency of their intrinsic fragility. Mountains are particularly vulnerable to climate change; they are expected to be the first ones hit by climate change.
Both natural and antrophogenic drivers are changing through climate and land-use transformation. Vegetation responds to these changes. Grasslands are dynamic communities, whose adaptation to changing conditions is signalled by a change in community composition. Such changes in community composition will have direct impact in ecosystem functioning (long-term C and N accumulation, fine root processes, productivity, soil respiration).
With the motivation of describing, understanding and assessing the role of vegetation composition in the carbon cycle, the project CAPACITI has been following the annual course of environmental and ecological events at semi-natural mountain pastures at the Pyrenees. In other words, this project, studied the annual carbon dynamics of semi-natural mountain pastures in relation to the plant-soil system processes which are expected to modulate the C balance of the ecosystem.
Different types of plants follow different functional strategies for optimization of the resources, and they also present –along the year- different patterns of change in their capacities such as photosynthetic fixation, belowground C allocation, and C loss via respiration. Species can be grouped into functional types that represent these plant functions. Life-forms (grasses, sedges, legumes, forbs, woody, mosses) are indicators of plant functional types and were chosen as background for the trait-base approach which is transversal to all activities of the study.
The studied pastures were located in the south west Pyrenees at montane and sub-alpine altitudes, namely: La Bertolina, Alinyà, and Castellar at 1300, 1700, and 1900 m a.s.l. respectively. In addition, there was one low-land pasture at the North-face, Lannemezan also available to the study (see Table 1 for details attached).
The project has achieved two main objectives organized around two major methodological approaches:
• Monitoring of the dynamics of the annual net ecosystem CO2 exchange and determine its main controlling factors. A specific aim was to determine whether the seasonal distribution of plant functional types can be detected in the short-term ecosystem exchange and what role it plays. This was achieved with continuous measurements of meteorological and micrometeorological variables combined with a thorough description of the vegetation.
• Monitoring of the variation in plant-soil system processes along the growing season and between plant guilds. The project used the measurement of natural abundance of isotopes at different compartment of the system to detect whether different temporal patterns arise between different functional types.
The project proposed quite intense data gathering involving frequent and comprehensive field sampling. The automatic continuous measurements provided by the micrometeorological station were in the first year of implementation and required as well intense follow-up. Populating the proposed database has been the main activity carried out during the project. Preliminary analyses on the data show that:
There is a clear seasonal dynamics in all studied parameters
There is difference between plant functional types in most of the studied parameters. However, the detail of the data invites to have a critical look at the division of the functional types
The relation between the ecosystem-scale fluxes and the ecosystem-survey data is under analysis beyond the time-frame of the project.
The implementation of management styles that favour the carbon uptake can lead to net accumulation in grasslands and pastures, thereby sequestering atmospheric carbon. Mitigation of CO2 emissions (and green house gas in general) is envisioned as a relevant ecosystem service and involves an added-value to the agro-pastoral systems that can provide such. Therefore, in addition of achieving the understanding about the processes behind the carbon dynamics, there is also need to determine locally whether we are tackling systems with a tendency to lose or capture carbon. The results of projects like CAPACITI should provide relevant information to stakeholder such as Climate Change Agencies and Regulating Bodies for pasture management, as well as land-owners themselves.
Details on the stations, project and group and host institute at http://fluxpyr.eu/eng/index.htm , http://ecofun.ctfc.cat and http://www.ctfc.cat/