EcoScan · guano-based monitoring of ecosystems – a novel approach to capture ecological processes underlying ecosystem health

guano-based monitoring of ecosystems – a novel approach to capture ecological processes underlying ecosystem health

Biodiversity loss, exacerbated by climate change is a great challenge facing all life on earth. Rapid and informative assessments of biodiversity are needed to detect and combat declines in biodiversity. Although many monitoring programs exist using various technologies and approaches (e.g. remote sensing, acoustics, visual observations, citizen science), such approaches tend to have limited taxonomic scope and tell little about the underlying processes that precede these end states. Many researchers are working on developing novel methods for the ‘Next Generation of Biodiversity Monitoring’ to complement existing monitoring approaches. Such new methods should standardisable across a large spatial scales and be amenable to automation. Environmental DNA (eDNA) based monitoring is acknowledged as a key element in future protocols for terrestrial and aquatic biomes. In our project, we aimed to test whether bats could contribute as landscape samplers to help deliver an improved eDNA-based monitoring for terrestrial ecosystems. Why bats? • Many monitoring schemes are site based, whereas bats actively sample at the landscape-scale, in a relatively fixed radius of a few kilometres around their roost. • eDNA is typically characterised by low amounts of degraded DNA and the associations between taxa detected can be difficult to infer, as it not certain that they were present in the same place at the same time. The short gut retention time of insectivorous bats ensures that freshly collected droppings contain a relatively well defined temporal sampling (12-24 hrs) of taxa who were present in the same sampling area, with good quality DNA. • Bats eat not only a wide diversity of prey items but huge quantities too – up to their own body weight per night during energetically demanding periods – ensuring diverse and plentiful samples. • Depending on species, temperate bat species either exclusively or regularly use the same sites as day roosts, ensuring a reliable and predictable collection point for fresh droppings. Using bats as samplers, it is possible to retrieve the DNA or RNA of many different groups due to trophic aggregation in the diet. In our project, we focused on bats, insects, plants, fungi and viruses. Plants form the base of ecosystem functioning and accumulate increased viral- and fungal load in response to stressors like climatic events. The fungi and viruses which grow on plants are ingested along with plant matter by insect herbivores who similarly have microorganisms (viruses and fungi) and may be eaten by a secondary consumer such as a bat. By collecting and sequencing bat droppings, we can get a rich temporal snap-shot of multiple levels of diversity in the environment. However, we can go far beyond simple presence-absence of the species in these groups. We can also reconstruct the interactions between them to understand ecological relationships, how these change over time, and in relation to climate and land use.

Data: CORDIS, © European Union