Response Doctoral Program

The tropics lost a whopping 4.1 million hectares of primary forests in 2022, equivalent to losing 11 football fields of forest per minute, according to research from the World Resources Institute. Numerous restoration projects worldwide target counteracting these large scales of forest destruction that are causing insurmountable loss of biodiversity. By planting native vegetation as well as by assisting in natural regrowth of vegetation, these projects aim to restore degraded forests back to their flourishing state. These efforts are not just about the trees. They are crucial for the recovery of animal communities too. However, it is unfortunately undermined by the limited data available on the influence of forest loss and regeneration on recovery of faunal species and communities.  

Need for Robust Biodiversity Monitoring Methods

Endeavors of forest regeneration are riddled with an interplay of ecological processes and feedback, often leading us down unexpected paths. This could, in turn, prevent forest ecosystems from realizing desired outcomes, which are typically the state of the forest ecosystem prior to degradation. To steer these efforts effectively, robust monitoring of ecosystem changes, especially wildlife health, is crucial. However, current challenges in monitoring terrestrial fauna often limit the evaluation of forest restoration projects to the assessment of plant diversity.

Monika Goralczyk, is a PhD student in the Ecosystems and Landscape Evolution Group at ETH Zurich as well as a RESPONSE fellow in the PhD program Science and Policy. She tackles this challenge by using a novel approach based on environmental DNA (eDNA) to quantify biodiversity in forests of differing conditions. eDNA consists of nuclear or mitochondrial DNA released by animals, plants, fungi, protists and prokaryotes into their environment. By utilizing eDNA metabarcoding, comprehensive data on the presence of multiple species can be gathered from a single sample. Additionally, since water transports particles with its flow, research confirms that collecting eDNA from rivers and streams holds potential for rapid and large-scale biodiversity monitoring.

Advancing the field of environmental DNA (eDNA)

Studies in the world of eDNA reveal that the traces of DNA left behind by wildlife are treasure troves of information, mingling with river waters and traversing landscapes these rivers meander through. However, many complex processes influence how long DNA can remain in water and how far it can travel. Monika’s PhD research combines multiple methods of data analysis to enhance the understanding of the application of eDNA in monitoring wildlife. Part of her project involves applying a hydrology-based transport model to an eDNA metabarcoding data to reveal mammal distributions and eDNA patterns in river catchments. This approach allowed her to test sampling strategies, with downstream sampling emerging as an efficient method to uncover the most mammal diversity using eDNA in the mountainous catchment.  

Monitoring wildlife in reforested watersheds in Colombia using eDNA

In spring and summer 2022, together with collaborators, Monika visited six sites of regenerating forests to assess biodiversity using eDNA metabarcoding. They selected sites within tropical humid forests in Colombia due to their global significance and crucial role in delivering ecosystem services, such as regulating the climate and water cycle. In each site they visited, they collected samples of soil and water. For comparison, they also sampled sites of pasture and well-conserved old growth forests to represent two reference states in forest succession. 

From these samples, DNA copies were amplified, sequenced and matched with reference databases to produce a list of detected mammals and soil biota. Mammals can disperse seeds, shape vegetation structure, and indicate food web balance, while soil biota plays vital roles in nutrient cycling and organic matter decomposition. These organisms both shape and respond to changes in environmental and biotic conditions, therefore allowing us to gain a better idea of forest health. By studying these forest communities and their responses to environmental factors, Monika’s research aims to provide a comprehensive understanding of the potential of eDNA to help assess and guide restoration and conservation efforts.

The sampling campaign was possible thanks to invaluable assistance of collaborators, including researchers and practitioners from organizations such as Instituto Alexander von Humboldt, PNN Sierra Nevada de Santa Marta, WWF Colombia, Biodiversa Foundation Colombia, Fundación Natura Colombia (Reserve Biological El Encenillo), Fundación Guanacas, representatives from the Ankamechu community, and forest reserves El Zoque, Bosque Guajira, and La Helenita. These collaborators work to promote healthy ecosystems through initiatives like assisted regrowth, protected area management, tree planting, watershed restoration, and more. Combining their expertise and local knowledge with eDNA assessment can provide a new view on the impact of forest restoration.

Stakeholder Workshops for Knowledge Co-Creation and Dissemination

To address the biodiversity crisis, it is crucial to bridge scientific research and conservation practice. Monika hopes to facilitate application of eDNA-based methods tailored to the needs of conservation practitioners through close collaboration. In 2023, Monika and colleagues from the ETH laboratory of Ecosystem and Landscape Evolution led an 8-day workshop with representatives of WWF Bhutan, Bhutanese government and WWF US. They focused on critical study design choices, data analysis, and effective ways to disseminate eDNA results to inform decision-makers. 

Building on the findings of her project, Monika is collaborating with WWF US, an organization with a longstanding commitment to wildlife and ecosystem conservation. Together, they are working to evaluate the feasibility and key areas where eDNA can provide cost-effective and relevant metrics for measuring conservation impact. 

Steps Forward for Knowledge Sharing: Online Course on Empowering Biodiversity Assessment Using eDNA 

Furthermore, Ecosystems and Landscape Evolution Group has also developed an online course on utilizing eDNA for assessing biodiversity, featuring data collected in this project as one of the case studies. This initiative aims to empower a wider audience with the knowledge of eDNA workflow from theory to application.

This article is co-authored by Monika Goralczyk and Mary Ann George (University of Zurich, RESPONSE Program office assistant).

The images are owned by Dominik Kirschner and the ELE Group, ETH.