Tarek S. El-Madany

Tarek S. El-Madany
Max Planck Institute for Biogeochemistry Jena | BGC · Department of Biogeochemical Integration

Dr. of Landscape Ecology

About

84
Publications
38,316
Reads
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1,109
Citations
Introduction
I'm curious to understand the interactions between nutrient and water availability and ecosystem functioning. To measure and understand how ecosystems respond to changes in resource availability I design experiments, analyze ecosystem-scale flux data, plant traits, remote sensing data, and use modeling approaches to gain new insight into ecosystem processes, interactions and feedbacks. Currently, I'm working in the MaNiP project with a focus on nutrient-availability and plant trait interactions.
Additional affiliations
September 2021 - present
Max Planck Institute for Biogeochemistry Jena
Position
  • Group Leader
Description
  • I'm leading the Biosphere-Atmosphere-Interactions and Experiments (BAIE) group. with a special emphasis on the MaNiP project.
November 2014 - present
Max Planck Institute for Biogeochemistry Jena
Position
  • PostDoc Position
June 2014 - November 2014
University of Münster
Position
  • Research Assistant
Education
October 2004 - May 2009
University of Münster
Field of study
  • Landscape ecology

Publications

Publications (84)
Article
Full-text available
Anthropogenic nitrogen (N) deposition and resulting differences in ecosystem N and phosphorus (P) ratios are expected to impact photosynthetic capacity, i.e. maximum gross primary productivity (GPPmax). However, the interplay between N and P availability with other critical resources on seasonal dynamics of ecosystem productivity remain largely unk...
Article
The inter-annual variability (IAV) of the terrestrial carbon cycle is tightly linked to the variability of semi-arid ecosystems. Thus, it is of utmost importance to understand what the main meteorological drivers for the IAV of such ecosystems are, and how they respond to extreme events such as droughts and heatwaves. To shed light onto these quest...
Article
Full-text available
Nutrient availability, especially of nitrogen (N) and phosphorus (P), is of major importance for every organism and at a larger scale for ecosystem functioning and productivity. Changes in nutrient availability and potential stoichiometric imbalance due to anthropogenic nitrogen deposition might lead to nutrient deficiency or alter ecosystem functi...
Article
Full-text available
Evapotranspiration denotes the transport of water vapor between an ecosystem and atmosphere comprising the biotic (transpiration) and abiotic (evaporation) components. Additionally, the water vapor transports the energy used for its vaporization, the latent heat. In the present study we compare the ecohydrological cycle of a mangrove on the Bay of...
Article
Full-text available
Understanding the impact of land use and land cover change on surface energy and water budgets is increasingly important in the context of climate change research. Eddy covariance (EC) methods are the gold standard for high temporal resolution measurements of water and energy fluxes, but cannot resolve spatial heterogeneity and are limited in scope...
Article
Remote sensing capabilities to monitor evergreen broadleaved vegetation are limited by the low temporal variability in the greenness signal. With canopy greenness computed from digital repeat photography (PhenoCam), we investigated how canopy greenness related to seasonal changes in leaf age and traits as well as variation of trees’ water fluxes (c...
Article
Understanding the CO2 flux over agricultural crop fields is critical because the temporal cycle is driven by both ecological environment and anthropogenic change. We analyzed the net ecosystem exchange of CO2 measured over a barley–rice double-cropping field using the eddy covariance method for 5 years. We conducted gap-filling based on u*-threshol...
Article
Full-text available
Peatlands have acted as net CO2 sinks over millennia, exerting a global climate cooling effect. Rapid warming at northern latitudes, where peatlands are abundant, can disturb their CO2 sink function. Here we show that sensitivity of peatland net CO2 exchange to warming changes in sign and magnitude across seasons, resulting in complex net CO2 sink...
Preprint
Full-text available
The Australian continent contributes substantially to the year-to-year variability of the global terrestrial carbon dioxide (CO2) sink. However, the scarcity of in-situ observations in remote areas prevents deciphering the processes that force the CO2 flux variability. Here, examining atmospheric CO2 measurements from satellites in the period 2009-...
Preprint
Evapotranspiration (ET) represents the largest water loss flux in drylands, but ET and its partition into plant transpiration (T) and soil evaporation (E) are poorly quantified, especially at fine temporal scales. Physically-based remote sensing models relying on sensible heat flux estimates, like the two-source energy balance model, could benefit...
Article
The eddy-covariance technique measures carbon, water, and energy fluxes between the land surface and the atmosphere at hundreds of sites globally. Collections of standardised and homogenised flux estimates such as the LaThuile, Fluxnet2015, National Ecological Observatory Network (NEON), Integrated Carbon Observation System (ICOS), AsiaFlux, AmeriF...
Article
Mixed species forests are known to have a higher gross primary productivity (GPP) and net primary productivity (NPP) than forests containing only one single tree species. Trees growing in mixtures are characterized by higher autotrophic respiration (Ra), this results in a lower carbon use efficiency of mixed species forests compared to monocultures...
Preprint
Full-text available
While the eddy covariance (EC) technique is a well-established method for measuring water fluxes (i.e., evaporation or 'evapotranspiration’, ET), the method is susceptible to many uncertainties. One such issue is the potential underestimation of ET when relative humidity (RH) is high (>70%), due to low-pass filtering with some EC systems. The influ...
Article
Understanding the critical soil moisture (SM) threshold (θcrit) of plant water stress and land surface energy partitioning is a basis to evaluate drought impacts and improve models for predicting future ecosystem condition and climate. Quantifying the θcrit across biomes and climates is challenging because observations of surface energy fluxes and...
Article
Full-text available
Sun-induced fluorescence in the far-red region (SIF) is increasingly used as a remote and proximal-sensing tool capable of tracking vegetation gross primary production (GPP). However, the use of SIF to probe changes in GPP is challenged during extreme climatic events, such as heatwaves. Here, we examined how the 2018 European heatwave (HW) affected...
Preprint
Full-text available
The eddy-covariance technique measures carbon, water, and energy fluxes between the land surface and the atmosphere at several hundreds of sites globally. Collections of standardised and homogenised flux estimates such as the LaThuile, Fluxnet2015, National Ecological Observatory Network (NEON), Integrated Carbon Observation System (ICOS), AsiaFlux...
Article
It is well documented that energy balance and other remote sensing-based evapotranspiration (ET) models face greater uncertainty over water-limited tree-grass ecosystems (TGEs), representing nearly 1/6th of the global land surface. Their dual vegetation strata, the grass dominated understory and tree dominated overstory, make for distinct structura...
Preprint
Full-text available
The input of liquid water to terrestrial ecosystems is composed of rain and non-rainfall water input (NRWI). The latter comprises dew, fog, and adsorption of atmospheric vapor on soil particle surfaces. Although NRWIs can be relevant to support ecosystem functioning in seasonally dry ecosystems, they are understudied, being relatively small, and th...
Article
Full-text available
The leaf economics spectrum1,2 and the global spectrum of plant forms and functions³ revealed fundamental axes of variation in plant traits, which represent different ecological strategies that are shaped by the evolutionary development of plant species². Ecosystem functions depend on environmental conditions and the traits of species that comprise...
Article
Full-text available
Remote sensing of solar-induced chlorophyll fluorescence (SIF) provides new possibilities to estimate terrestrial gross primary production (GPP). To mitigate the angular and canopy structural effects on original SIF observed by sensors (SIF obs ), it is recommended to derive total canopy SIF emission (SIF total ) of leaves within a canopy using can...
Article
Full-text available
Plant transpiration links physiological responses of vegetation to water supply and demand with hydrological, energy, and carbon budgets at the land–atmosphere interface. However, despite being the main land evaporative flux at the global scale, transpiration and its response to environmental drivers are currently not well constrained by observatio...
Article
The coupling of radiative transfer, energy balance, and photosynthesis models has brought new opportunities to characterize vegetation functional properties from space. However, these models do not accurately represent processes in ecosystems characterized by mixtures of green vegetation and senescent plant material (SPM), in particular grasslands....
Article
Full-text available
Understanding the dependencies of the terrestrial carbon and water cycle with meteorological conditions is a prerequisite to anticipate their behaviour under climate change conditions. However, terrestrial ecosystems and the atmosphere interact via a multitude of variables across temporal and spatial scales. Additionally these interactions might di...
Article
Many satellite missions rely on modeling approaches to acquire global or regional evapotranspiration (ET) products. However, a current challenge in ET modeling lies in dealing with sub-pixel heterogeneity, as models often assume homogeneous conditions at the pixel level. This is particularly an issue for heterogeneous landscapes , such as tree-gras...
Article
Full-text available
Analyzing tree structural features and capturing their temporal dynamic is challenging but crucial for determining key state variables related to plant function, management practices, and aboveground vegetation stocks. Terrestrial laser scanning (TLS) provides a mean for representing those key variables in three-dimensional space and through time....
Article
Full-text available
Understanding the dependencies of the terrestrial carbon and water cycle is a prerequisite to anticipate their be- haviour under climate change conditions. However, terrestrial ecosystems and the atmosphere interact via a multitude of vari- ables, time- and space scales. Additionally the interactions might differ among vegetation types or climatic...
Article
Full-text available
Globally, soils store two to three times as much carbon as currently resides in the atmosphere, and it is critical to understand how soil greenhouse gas (GHG) emissions and uptake will respond to ongoing climate change. In particular, the soil-toatmosphere CO2 flux, commonly though imprecisely termed soil respiration (RS), is one of the largest car...
Preprint
Full-text available
Understanding the dependencies of the terrestrial carbon and water cycle is a prerequisite to anticipate their behaviour under climate change conditions. However, terrestrial ecosystems and the atmosphere interact via a multitude of variables, time- and space scales. Additionally the interactions might differ among vegetation types or climatic regi...
Article
Full-text available
Plant transpiration links physiological responses of vegetation to water supply and demand with hydrological,energy and carbon budgets at the land-atmosphere interface. However, despite being the main land evaporative flux at the global scale, transpiration and its response to environmental drivers are currently not well constrained by observations...
Data
This is the supplementary material to the manuscript 'Drought and heatwave impacts on semi-arid ecosystems' carbon fluxes along a precipitation gradient'
Article
Drought and heat events, such as the 2018 European drought, interact with the exchange of energy between the land surface and the atmosphere, potentially affecting albedo, sensible and latent heat fluxes, as well as CO 2 exchange. Each of these quantities may aggravate or mitigate the drought, heat, their side effects on productivity, water scarcit...
Article
Full-text available
In summer 2018, Europe experienced a record drought, but it remains unknown how the drought affected ecosystem carbon dynamics. Using observations from 34 eddy covariance sites in different biomes across Europe, we studied the sensitivity of gross primary productivity (GPP) to environmental drivers during the summer drought of 2018 versus the refer...
Article
Full-text available
Soil CO2 efflux is the second-largest carbon flux in terrestrial ecosystems. Its feedback to climate determines model predictions of the land carbon sink, which is crucial to understanding the future of the earth system. For understanding and quantification, however, observations by the most widely applied chamber measurement method need to be aggr...
Article
Full-text available
The thermal-based two-source energy balance (TSEB) model has accurately simulated energy fluxes in a wide range of landscapes with both remote and proximal sensing data. However, tree-grass ecosystems (TGE) have notably complex heterogeneous vegetation mixtures and dynamic phenological characteristics presenting clear challenges to earth observatio...
Article
Full-text available
The dynamics of biochemical processes in terrestrial ecosystems are tightly coupled to local meteorological conditions. Understanding these interactions is an essential prerequisite for predicting, e.g. the response of the terrestrial carbon cycle to climate change. However, many empirical studies in this field rely on correlative approaches and on...
Preprint
Full-text available
Abstract. Remote Sensing (RS) has traditionally provided estimates of key biophysical properties controlling light interaction with the canopy (e.g., chlorophyll content ( C <sub>ab</sub>) or leaf area index (LAI)). However, recent and upcoming developments in hyperspectral RS are expected to lead to a new generation of products such as vegetation...
Preprint
Full-text available
Semi-arid grasslands and other ecosystems combine green and senescent leaves featuring different biochemical and optical properties, as well as functional traits. Knowing how these properties vary is necessary to understand the functioning of these ecosystems. However, differences between green and senescent leaves are not considered in recent mode...
Article
Full-text available
Sun-Induced fluorescence at 760 nm (F760) is increasingly being used to predict gross primary production (GPP) through light use efficiency (LUE) modeling, even though the mechanistic processes that link the two are not well understood. We analyzed the effect of nitrogen (N) and phosphorous (P) availability on the processes that link GPP and F760 i...
Article
Full-text available
Evaporation (E) and transpiration (T) respond differently to ongoing changes in climate, atmospheric composition, and land use. It is difficult to partition ecosystem-scale evapotranspiration (ET) measurements into E and T, which makes it difficult to validate satellite data and land surface models. Here, we review current progress in partitioning...
Article
Full-text available
The most recent efforts to provide remote sensing (RS) estimates of plant function rely on the combination of Radiative Transfer Models (RTM) and Soil-Vegetation-Atmosphere Transfer (SVAT) models, such as the Soil-Canopy Observation Photosynthesis and Energy fluxes (SCOPE) model. In this work we used ground spectro-radiometric and chamber-based CO...
Article
Full-text available
The thermal-based Two-Source Energy Balance (TSEB) model has successfully simulated energy fluxes in a wide range of landscapes. However, tree-grass ecosystems (TGE) have notably complex heterogenous vegetation mixtures and dynamic phenological characteristics presenting clear challenges to earth observation and modeling methods. Therefore, the TSE...
Article
Full-text available
Local meteorological conditions and biospheric activity are tightly coupled. Understanding these links is an essential prerequisite for predicting the Earth system under climate change conditions. However, many empirical studies on the interaction between the biosphere and the atmosphere are based on correlative approaches that are not able to dedu...
Article
Full-text available
Soil CO2 efflux is the second largest carbon flux in terrestrial ecosystems. Its feedback to climate determines model predictions of the land carbon sink, which is crucial to understanding the future of the earth system. For understanding and quantification, however, observations by the most widely applied chamber measurement method need to be aggr...
Article
Full-text available
Plain Language Summary Plants are Earth's biggest contributor for cleaning the atmosphere of carbon dioxide and remove around one quarter of the carbon dioxide emitted by humans each year. However, this contribution cannot be measured directly and has to be inferred or modelled on the basis of related parameters. This introduces large uncertainties...
Article
Full-text available
Evaporation (E) and transpiration (T) respond differently to ongoing changes in climate, atmospheric composition, and land use. Our ability to partition evapotranspiration (ET) into E and T is limited at the ecosystem scale, which renders the validation of satellite data and land surface models incomplete. Here, we review current progress in partit...
Article
Full-text available
To understand what is driving spatial flux variability within a savanna type ecosystem in central Spain, data of three co-located eddy covariance (EC) towers in combination with hyperspectral airborne measurements and footprint analysis were used. The three EC systems show consistent, and unbiased mass and energy fluxes. Nevertheless, instantaneous...
Article
Eddy covariance (EC) provides ecosystem-scale estimates of photosynthesis (Ph) and evapotranspiration (ET; the sum of plant transpiration [T] and evaporation [Es]). Separating ET into its components is becoming necessary for linking plant-water use strategies to environmental variability. Based on optimality principles, a data-model based approach...
Article
Full-text available
Tree-grass ecosystems are widely distributed. However, their phenology has not yet been fully characterized. The technique of repeated digital photographs for plant phenology monitoring (hereafter referred as PhenoCam) provide opportunities for long-term monitoring of plant phenology, and extracting phenological transition dates (PTDs, e.g., start...
Article
Full-text available
We present the R package bigleaf (version 0.6.5), an open source toolset for the derivation of meteorological, aerodynamic, and physiological ecosystem properties from eddy covariance (EC) flux observations and concurrent meteorological measurements. A ‘big-leaf’ framework, in which vegetation is represented as a single, uniform layer, is employed...