Few plant functional types (PFTs) with fixed average traits are used in land surface models (LSMs) to consider feedback between vegetation and the changing atmosphere. It is uncertain if highly diverse vegetation requires more local PFTs. Here, we analyzed how 52 tree species of a megadiverse mountain rain forest separate into local tree functional types (TFTs) for two functions: biomass production and solar radiation partitioning. We derived optical trait indicators (OTIs) by relating leaf optical metrics and functional traits through factor analysis. We distinguished four OTIs explaining 38%, 21%, 15%, and 12% of the variance, of which two were considered important for biomass production and four for solar radiation partitioning. The clustering of species-specific OTI values resulted in seven and eight TFTs for the two functions, respectively. The first TFT ensemble (P-TFTs) represented a transition from low to high productive types. The P-TFT were separated with a fair average silhouette width of 0.41 and differed markedly in their main trait related to productivity, Specific Leaf Area (SLA), in a range between 43.6 to 128.2 (cm2/g). The second delineates low and high reflective types (E-TFTs), were subdivided by different levels of visible (VIS) and near-infrared (NIR) albedo. The E-TFTs were separated with an average silhouette width of 0.28 and primarily defined by their VIS/NIR albedo. The eight TFT revealed an especially pronounced range in NIR reflectance of 5.9% (VIS 2.8%), which is important for ecosystem radiation partitioning. Both TFT sets were grouped along elevation, modified by local edaphic gradients and species-specific traits. The VIS and NIR albedo were related to altitude and structural leaf traits (SLA), with NIR albedo showing more complex associations with biochemical traits and leaf water. The TFTs will support LSM simulations used to analyze the functioning of mountain rainforests under climate change.
<p>Ecosystems play an important role in controlling the exchange of energy, water and carbon between the land surface and the atmosphere, which contributes to the regulation of the climate through biogeochemical process. Changes in vegetation or biomass impacts the microclimatological conditions of the landscapes with feedbacks to the heat and water budgets. Knowledge about the dynamics and driving factors of the exchange processes contributes to our understanding of the land surface &#8211; atmosphere interactions as drivers of the Earth&#8217;s surface energy budget.</p> <p>In the Tumbesian mountain dry forest (MDF) in the Laipuna reserve on the western escarpment of the Andes mountains in South Ecuador two eddy-covariance measurement stations have been installed over natural forest and an anthropogenic replacement system to observe atmospheric water and carbon fluxes. The MDF is characterized by a distinct seasonality, which can be divided into a dry (May - December) and wet (November - May) season following the inter-hemispherical shift of the ITCZ. Mean monthly precipitation totals ranges between 50 and 400mm with an annual amount of 650mm, while the temperature varies between 21 &#8211; 26&#176;C. The forest ecosystem is dominated by deciduous trees and hold a clear annual cycle in the water budget and carbon sequestration. In the scope of global climate change such water limited landscapes are strongly vulnerable to climatic stress situations which lead to changes in the phenological cycles in the ecosystem associated with feedbacks to the water and carbon cycle. The aim is thus, to investigate the energy, water and carbon dynamics along a land use gradient in order to estimate the impact of deforestation on net-ecosystem exchange and evapotranspiration in the MDF region. The study shows first results of microclimatological conditions, such as radiative fluxes, moisture and soil conditions of both sites as well as water and carbon fluxes.</p>
<p>The tropical mountain forest (TMF) in the Andes of SE-Ecuador is globally one of the hottest hotspots of biodiversity. However, biodiversity and ecosystem services are threatened by environmental changes (climate and land use changes). This particularly holds for the mountain rain forest in the river valley of the Rio San Francisco between Loja and Zamora (Ecuador), where ecosystem water and carbon regulation are important services, expected to be especially affected adversely. An interdisciplinary team of Geo-, Bioscientists and researchers from socio-economy have investigated environmental change impacts on ecosystem water services over the last two decades in this area. Particularly changes in canopy water fluxes due to environmental change are one major objective of the ongoing research unit RESPECT (Environmental changes in biodiversity hotspot ecosystems of South Ecuador: RESPonse and feedback effECTs). In the talk, a general overview on environmental change impacts on canopy water fluxes derived from field measurements such as Eddy Covariance and Remote Sensing are presented. To look into future developments, well-adopted Land Surface Models (LSM) are required including suitable plant functional types (PFTs) and focal ecological processes, properly adapted to the complexity of the TMF. In the second part of the talk, the concept and first results of a new way of LSM modelling will be presented. The integrated concept will be finally used to unveil the resistance of the two ecosystem services against future climate change under different land use scenarios.&#160;&#160;</p>
<p>Knowledge about microclimatological conditions strongly contributes to our understanding of land surface &#8211; atmosphere interactions as drivers of the Earth&#8217;s surface energy budget. Particularly the radiative fluxes are major determinants providing energy for vital climate processes and are crucial for climate warming, water availability, primary productivity and ecosystem services. The partitioning into sensible and latent heat fluxes are highly dependent on the land coverage and represent feedback effects affecting the cycling of heat and water in the vegetation-atmosphere continuum. In the Reserva Biologica San Francisco (RBSF) on the eastern escarpment of the South Ecuadorian Andes on 2000m elevation above sea level (a.s.l.) two eddy-covariance measurement stations have been installed over natural rain forest and pasture ecosystem to observe atmospheric water and carbon fluxes. The aim is to assess net-ecosystem exchange (NEE) and evapotranspiration (ET) in order to estimate the impact of deforestation on the carbon sink function and the water availability. Additionally, microclimatological conditions in terms of e.g. radiative fluxes and soil conditions are supposed to further disentangle effects of the respective land surface properties on the environmental conditions. Over the last three years generally higher water fluxes could be observed during daytime over the forest ecosystem compared to pasture. Concerning NEE a clear carbon sink was revealed for both ecosystems indicated by a mean gross primary productivity (GPP) of 12.7 gC/m&#178;day (forest) and 6.5 gC/m&#178;day (pasture), while a mean ecosystem respiration (Reco) of 10.6 gC/m&#178;day (forest) and 5.9 gC/m&#178;day (pasture) was obtained. However, a mean NEE of 2.1 gC/m&#178;day (forest) and 0.6 gC/m&#178;day (pasture) clearly shows the stronger productivity of the forest ecosystem and thus, a higher carbon sink as a contribution to climate change mitigation.</p>
<p>The megadiverse Andean mountain rain forests in southern Ecuador are threatened by climate and land use change, which are expected to alter biodiversity and thus functional traits impacting ecosystem processes. However, the high biodiversity of tropical mountain forests is still poorly represented in Land Surface Models (LSMs). We developed a biodversity-informed LSM entitled HUMBOL-TD (Hydroatmo Unified Model of Biotic interactions and Local Trait Diversity) to analzye the impact of climate and land-use change on carbon- and water fluxes. HUMBOL-TD consists of three coupled submodels specialized to represent different processes at the land surface. As such, energy- and water fluxes between land surface and atmosphere (LSMatmo) are simulated by the Community Land Model (CLM), vegetation dynamics including C, N and P cycling (LSMbio) are simulated by the Lund-Potsdam-Jena General Ecosystem Simulator (LPJ-GUESS), while the soil hydrology (LSMhydro) is represented by the Catchment Modeling Framework (CMF). A first test towards the simulation of the mountain forests and their replacement systems is conducted for a pasture site at 2000 m elevation. The model is parameterized and validated using a year of local site data. The first runs of the model enable the investigation of the differences in accuracy of modeled changes in the carbon- and water fluxes between coupled, partially coupled (LSMatmo &#8211; LSMbio, LSMatmo &#8211; LSMhydro, LSMbio &#8211; LSMhydro) and the fully coupled model (LSMatmo &#8211; LSMbio &#8211; LSMhydro).</p>
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