Monitoring mangroves from afar

  • This month’s blog is written by our Remote Sensing Analyst, Helena Schindler Dite, highlights the importance of mangrove forests for marine conservation. Many of TCarta’s projects fall within the realm of the Blue Economy with projects globally.

    Mangroves are crucial as their roots secure the ground, ensuring a natural defence mechanism to protect our coastlines from erosion. Simultaneously, they act as fish nurseries, providing habitats to foster sustainable fishing practices and boost biodiversity. They also absorb a significant amount of Carbon, helping to offset our Carbon footprints globally.

    In the words of Pisit Charnsanoh (MAP, 2018), “The mangrove forest sustains the people who sustain the mangrove forest”.

    Mangroves and us

    The Blue Carbon Initiative estimates that despite covering 2% of the Earth’s surface, Marine and Coastal Habitats store 83 % of the world’s Carbon. These estimations encompass Mangrove Forests. Mangroves are of significant ecological interest due to their ability to protect the coastline from erosion as well as sequester (take in and store) atmospheric Carbon Dioxide, globally occupying 13.8 Mha. They can store such high levels of Carbon for several reasons.

    Preferring warmer climes, they are situated along most of the world’s tropical coastlines, meaning that they are highly productive for long periods of the day, mostly all year round. With climate change inducing warming, this is means that their locations are migrating to other higher latitudes.

    Monitoring mangrovesMonitoring mangroves

    Figure 1 - Views from outside (left), and inside (right) Abu Dhabi mangrove forests as captured by the field team at Nautica Environmental Associates. Notice the interesting root (propagules) structure where they stick out of the ground. These can be seen both in their exposed (left) and submerged (right) environment. These mangroves are especially unique in that they are stunted, growing to approximately 5 m in height, due to the unique environmental conditions.

    These environments are now under threat, primarily because of human activities altering the characteristics of marine environments. Yes, we are once again to blame!

    Changes in salinity, pollutants and sedimentation resulting from human effects upon the intertidal/marine environment all contribute to the severe endangerment of these crucial habitats, with an estimated loss of 19% between 1980 – 2005.

    Altering water flow dynamics changes the location of mangroves, as reproduction occurs via floating propagules. It also changes salinity gradients, which mangroves, specially adapted to be salt tolerant, are particularly sensitive to.

    Protecting and monitoring these forests facilitates the mitigation of climate change, offering a cost effective natural solution for the protection of humans from floods, erosion, and mass wasting from extreme weather events.

    Innovations in Remote Sensing

    The only way to monitor mangrove health on a large enough scale is by employing the use of satellite imaging technologies. The benefit of satellite imagery includes the ability to utilise historical imagery to provide a change analysis to examine the effects of climate change and development on mangroves over time, allowing trends to be identified and mitigation to be implemented.

    Monitoring mangroves

    Figure 2 - The images above over Mangrove National Park, show how manipulating remotely sensed data beyond the visible can be used to guide the identification (Image 2) and health (Image 3) of protected habitats for conservation. Images are derived from DigitalGlobe’s WorldView-2 at 50 cm resolution.

    The remote sensing team at TCarta have already been involved in exciting projects contributing to the preservation and monitoring of mangroves on an ecosystem scale. Through using the latest in satellite imaging technology, TCarta have been performing in-depth, highly valuable analyses to quantify the biophysical status of mangrove forests, with the ability to view features with a pixel size of 30 cm! Though we may not be able to prevent climate change, we can manage and understand the health and impact on these fragile ecosystems while observing remotely from space with no environmental impact.

    Traditionally marine focussed, TCarta are now encroaching on the intertidal and coming closer to land, whilst remaining as far away as feasibly possible from the comfort of our Bristol based desks!

    Well ….. we do get out sometimes!

    Monitoring mangroves