Landscapes at a crossroads: using remote sensing to help nature recovery

Vast areas of land all around the globe have been reshaped by humans, often resulting in simplified and uniform landscapes. The UK stands out as a prime example of this transformation, having become one of the most nature-depleted countries on Earth. These changes have reduced how complex our landscapes are. As a result, people and the biodiversity that we share the planet with are more vulnerable to the rapid global changes.

While today’s landscapes tell a story of transformation, they also present a story of opportunity. Tackling the growing challenges of climate change and biodiversity loss (and all the uncertainties that they bring along) will require re-designing and restoring our landscapes into diverse and adaptable systems. The question is how can we adopt more sustainable landscape management practices that build resilient natural systems and bring a wealth of benefits for both people and biodiversity?

Through my PhD research, I am exploring how Nature-based Solutions (NbS) can play a part in increasing the complexity, function and resilience of ecosystems. NbS help us to manage, protect and restore ecosystems in ways that benefit both to people and biodiversity across entire landscapes. Through the lens of remote sensing technology (satellites, drones and other sensors) and the analysis of spatial patterns, this research is based at Sussex where I aim to bring new insights for landscape management and nature recovery plans.

Remote sensing is the process of gathering information about objects or areas from a distance, using specialist cameras or technology.

What is structural complexity and why do we need it?

Put simply, structural complexity is how vegetation is distributed within the 3D space of a given area. It refers not only to how the different vegetation elements, such as leaves or woody structures, are are arranged in vertical space, but also to the composition and spatial configuration of important elements within a landscape, such as patches and corridors.

On a landscape scale, greater complexity often enhances connectivity by offering a wider range of suitable habitats for biodiversity to move through a diversified network of landscape elements. It also leads to increased redundancy, with multiple patches, vegetation and habitat types performing similar ecological functions. All these properties enhance landscapes’ ability to resist and recover from disturbances, such as the spread of pests and diseases. At the same time, more complex and diverse landscapes have a greater ability to provide a wide range of ecosystem functions and services, such as carbon storage and nutrient cycling.

By restoring the diversity and complexity of ecosystems, we can transform simplified and depleted landscapes into functional systems. From a local to a large spatial scale, this restoration is essential to address future climate changes and tackle the damaging effects of biodiversity loss. However, many uncertainties remain on which restoration strategies are most effective, how to integrate them with other land uses, and how to combine the needs of the people that manage and depend on these landscapes.

Restoring ecological complexity and diversity through nature-based solutions

To reverse the trends of land use and land cover changes, NbS are attracting interest globally for their potential to put nature on a path of recovery while balancing it with food and resource production.

The scan above show Pearcelands Wood at Wakehurst, and one of its trees. The colours show shows the different heights, with the highest in red and lowest in blue. This technology allows us to study the structure of different ecosystems with a very high resolution.

This research project is assessing how some NbS, such as agroforestry, rewilding and natural regeneration, influence ecosystem functioning at a local scale. To study these intricate relationships, a combination of high-resolution remote sensing technology, including laser scanning (LiDAR) and unmanned aerial vehicles (i.e. drones), allows to unravel the impacts of different land management practices.

This project brings together Wakehurst, Sussex Wildlife Trust, Nymans National Trust, the Knepp Estate, and private landowners and local farmers across Sussex, combining management insights from areas where NbS are being implemented. These partnerships allow to study the impacts of NbS, whilst also generating scientific evidence that can inform future management and restoration strategies.

Exploring landscape multifunctionality and resilience

Understanding the local effects of NbS on ecosystems is crucial for evaluating their effectiveness in restoring biodiversity and mitigating the effects of climate change. However, studying the broader landscape-scale impacts of NbS is equally important. By exploring landscapes across Sussex, remote sensing (e.g. satellite imagery) reveals spatial patterns and measures ecosystem functions that allow to evaluate the impacts of different land uses and NbS on a larger scale.

By uncovering these complex links between patterns and processes, my research will help us to rethink how landscapes can provide multiple benefits to people while supporting biodiversity. In addition to this multifunctionality, ensuring that landscapes will be resilient to future climate scenarios will require more evidence. And for that, remote sensing data is being applied in this study to uncover ways to strengthen landscape’s ability to endure and recover from disturbances, such as droughts and floods.

From the High Weald to the South Downs, the diversity and complexity of Sussex landscapes offers a valuable setting to explore pathways for nature recovery through remote sensing in areas with increasing human pressures.

Despite the uncertainties about the most effective approaches to restore nature and how to integrate different solutions, ongoing research will help us to tell a story of opportunity - from uniform and simplified landscapes into resilient, multifunctional and thriving ones.

I am hoping that in the next 3 years of my PhD, the ideas and tools you have read here will allow us to shed light on effective and integrated approaches to recover our landscapes in a time where we need it the most. I envision a future where our landscapes can sustain us all while flourishing with life and this research is dedicated to make that vision closer to reality.

Guilherme Castro is a PhD student supervised by Dr. Cristina Garcia and Professor Julia Koricheva from Royal Holloway University of London and by Dr. Justin Moat from Royal Botanic Gardens, Kew. The PhD project is supported by London NERC Doctoral Training Programme.