Joint research project

Monitoring macrophyte physiology using proximal and remote sensing (MacroSense)

Project leaders
Paolo Villa, Viktor Toth
UNGHERIA - HAS (MTA) - Accademia Ungherese delle Scienze
CNR/HAS (MTA) 2016-2018
Earth system science and environmental technologies
Thematic area
Earth system science and environmental technologies
Status of the project

Research proposal

Introduction and study areas
Macrophytes communities are a key component of shallow inland water ecosystems and remote/proximal sensing can effectively contribute to understand and monitor their dynamics. Spectroradiometric information can give crucial information about physiological, e.g. leaf pigments and chlorophyll fluorescence, as well as morphological parameters, e.g. canopy density and LAI. The combination of these parameters constitutes a synoptic description of plant photosynthetic activity and health status. The integration of physiology and spectroradiometric can describe spatial heterogeneity of vegetation and retrospectively assess ecological dynamics that could highlight mechanism of response to external stressors and environmental changes.A strong link between spectral response and macrophyte physiology features is the basis for effectively exploiting Earth Observation (EO) data in order to deliver large scale monitoring products. The new generation of EO platforms, and in particular the Copernicus Sentinel-2 mission equipped with the MSI multispectral high resolution sensor, are a step forward in terms of operational flexibility and spectral-temporal capabilities for environmental monitoring in inland water ecosystems.
This joint proposal will focus on the study of macrophyte physiology using proximal and remote sensing in two European areas where aquatic vegetation plays and important role for ecosystem services: Lake Balaton and wetlands of the Kis-Balaton Water Protection System (Hungary) and Mantua lakes system (Italy): i) Lake Balaton (centre coordinates: 46°50'8.47" N, 17°43'47.29" E) is a large and shallow lake characterized by a biological gradient of trophic; ii) the Kis-Balaton Water Protection System area (KBWPS; centre coordinates: 46°39'31.02" N, 17°11'37.72" E) was designed in response to the increasingly eutrophication of Lake Balaton and consists of a system of shallow lakes and floodable wetlands; iii) the Mantua lakes system (centre coordinates: 45°10'06" N, 10°47'02" E), are three semi-artificial shallow hypertrophic lakes, hosting annual stands of macrophytes communities.

The study areas were subject of extensive in situ data collection by the proponent institutes: MTA ÖK-BLI and CNR-IREA. Data available cover: i) Lake Balaton and KBWPS: water quality data (2000-2015), morphological data of emergent (1999-2015) and submerged macrophytes (1999-2015), photo-physiological data of submerged (2002-2015) and emergent macrophytes (2009-2015), sediment characteristics (2003, 2006, 2010, 2012), hyperspectral airborne data (EUFAR, 2010), LIDAR airborne data (EUFAR, 2010); ii) Mantua lakes system: in situ spectra of water and aquatic plants (2007-2015), biomass and elemental content data of floating-leaved and submerged macrophytes (2006, 2007, 2014), hydro-chemical data (2006-2015), sediment characteristics (2007, 2014), hyperspectral airborne data (MIVIS 2007; APEX 2011 and 2014).

The methodological approach of MacroSense is articulated into two main activities:

Eco-physiological and spectroradiometric data gathering and analysis (A1)
1) Data gathering (available from past campaigns): seasonal data of macrophytes (emergent, floating-leaved and submerged) monitoring: growth dynamics, plant morphology, plant photo-physiology, macrophyte genetics. Physico-chemical properties of water and sediment.
2) Data collection: in situ and laboratory determination of photo-physiological, morphological and spectroradiometeric parameters of major emergent and floating leaved macrophytes: Phragmites australis, Typha angustifolia, Nelumbo nucifera, Nuphar lutea, Nymphaea alba and Trapa natans. They will be acquired over a gradient of trophic status and water/sediment characteristics, at the maximal growth time (May-June) and at the climax of vegetation period (July/August).
3) Parameters covered: morphological assessment of plants, spectroradiometric and photo-physiological (chlorophyll fluorescence, leaf pigments content) measures. Additional data for sediment and water quality characterization for selected sampling sites.
4) Instruments used: chlorophyll fluorometer (WALZ, PAM-2500), leaf chlorophyll meter (atLEAF+), spectroradiometers (Ocean Optics, USB2000+, ASD FieldSpec Full Resolution Pro, Spectral Evolution SR3500) laboratory spectrophotometers (Shimadzu UV-1601) and spectrometer (Varian AA240FS).

EO data processing and mapping products analysis (A2)
1) Data gathering: collection of seasonal (2016-2018) multitemporal Sentinel-2 MSI data (one satellite operational from October 2015, the second to be launched in 2016) covering the growing season from emergence to senescence (March-October). The areal coverage of will comprise KBWPS and Mantua lakes, and selected parts of Lake Balaton coastal areas. UAV camera images will be collected over test vegetation stands.
2) Pre-processing: including atmospheric effect correction (6SV1 and/or ATCOR codes), derivation of time series of spectral vegetation indices (SVIs) combining two or three spectral bands.
3) Optimal spectral proxies evaluation and model assessment: selection of optimal spectral proxies (i.e. SVIs) for different physiological parameters from in situ spectroradiometric and ecophysiology-morphology data through statistical separability analysis. Assessment of best semi-empirical model relating selected proxies and macrophyte bio-physical parameters.
5) Bio-physical and photo-physiological mapping: derivation of products showing spatial and temporal (seasonal and inter-annual) patterns of macrophyte eco-physiological parameters derived from EO data (including validation for most relevant parameters) using the calibrated models.
6) Ecological analysis: studying the implications of environmental factors connected to spatial and temporal patterns emerged from the analysis of photo-physiological activity of macrophytes over the study areas.

Research goals

The objective of this proposal is to set up a multidisciplinary experiment based on proximal and remote sensing data for studying macrophyte physiology under two main aspects: assessing spatial-temporal patterns of different communities (emergent floating-leaved, and free-floating plants) and monitoring their eco-physiological and morphological parameters. The results expected will comprise: 1) accurate mapping of macrophytes communities and analysis of spatial evolution of their phenological cycles, and 2) mapping the evolution of eco-physiological and morphological parameters through semi-empirical modelling based on spectral EO data. The approach and demo of EO capabilities could be extended to similar environments (shallow and wetland ecosystems). Moreover, the results of the joint project activities could help regional and local authorities involved in ecosystem management to better understand, monitor and act in order to protect and control macrophytes in shallow water ecosystems and their provision of ecosystem services.
The proposal is closely related to the EU FP7 INFORM ( project, where the Lake Balaton (including KBWPS) and Mantua lakes system are case studies for macrophytes detection and monitoring. MacroSense activities will further strengthen the collaboration between IREA and BLI, through sharing of expertise, joint data analysis and presentation to conferences, and publication of two papers in relevant international journals.

Last update: 18/07/2024