The shallow coastal areas of lakes are often inhabited by a variety of aquatic plants, known as “macrophytes”. The rooted macrophytes comprise many different species and constitute an extremely valuable component of the aquatic ecosystem, as an important long-term indicator of water and sediment quality. This is why their monitoring is often prescribed by law (e.g. for EU Member States by the Water Framework Directive[1] and by Natura 2000[2]).

When compared to in situ measurements, products based on Earth Observation are better suited to tackle such needs, as they can cover large and remote areas with remarkable frequency.

What is the problem?

  • Ecological researchers often need to carry out environmental assessments at temporal and spatial scales which can be difficult to achieve using in situ-only sampling methods.
  • Monitoring and reporting on the status of aquatic vegetation is an obligation of each EU Member State. Field sampling, however, may be time-consuming and costly when it comes to assessing large or remote areas.

How does EOMORES address it?

There are several options available for aquatic vegetation monitoring.

  • Mapping the presence of macrophytes, both historically and in near-real-time: the synoptic assessment of submerged and emerged communities of aquatic plants, and their variations, as provided by EOMORES, can be used both for Water Framework Directive reporting and for performing ecological studies.
  • Assessing plant health: analysing the way in which sunlight interacts with plants in different portions of the electromagnetic spectrum, EOMORES can provide information on biochemical and structural water quality
  • Satellite data, acquired in multi-spectral bands, can be used to observe any variations of the leaf area index (LAI), a proxy of plant health (the higher the better) over time and space.

[1] Directive 2000/60/EC of the European Parliament and of the Council of 23 October 2000 establishing a framework for Community action in the field of water policy

[2] Council Directive 92/43/EEC of 21 May 1992 on the conservation of natural habitats and of wild fauna and flora

EOMORES in action: Mapping macrophytes in perialpine lakes

The perialpine lakes in northern Italy are characterised by the presence of large quantities of aquatic vegetation. Both helophytes (mainly Phragmites australis) and floating hydrophytes are present. These local species are an important element of the freshwater ecosystem, fulfilling multiple functions, such as carbon sequestration, habitat provision and nutrient uptake.

Figure one: High resolution spatial imagery from WorldView-2 data acquired on 17 June 2018 was used to map macrophyte types (on the left) and leaf area index (on the right) in Lake Annone, a peri-alpine lake in the Italian region of Lombardia).