In a collaborative study led by researchers at the University of Helsinki, analysis of 900 species over a 20-year period showed that biodiversity enhances ecosystem stability and helps safeguard natural communities in a changing environment.
Alongside climate change, biodiversity loss caused by human activity is one of the greatest environmental challenges of our time. A study conducted at the Research Centre for Ecological Change, University of Helsinki investigated how the diversity of natural communities affects their stability amid rapid environmental change.
The results of the study show that diverse natural communities are more stable over time than those with fewer species. This is due to the fact that different species respond differently to environmental change – while some species suffer, others can continue functioning and help maintain the stability of the community as a whole. The researchers also observed that the mechanisms associated with stability vary between taxonomic groups: for some, stability is mainly based on the number of species, while the key factor for others is the functional composition of the community and the way in which species traits supplement each other.
The study was based on an exceptionally comprehensive dataset covering the distributions of 900 species—including birds, butterflies and moths, small and large mammals, and freshwater phytoplankton—in Finland over a 20-year period.
The researchers also demonstrated that so-called functional diversity is a key factor in stabilising natural communities. For example, the functional diversity of a community composed of strictly insectivore birds is narrower than that of a community comprising birds that eat insects, berries and fish. The greatest threat is faced by communities whose species richness and functional diversity are both narrow – the number of species is low, and the species are very alike. In such cases, most of the species in the community are sensitive to the same environmental changes, making it more vulnerable to changes for example in key food resources or abiotic conditions.§
“The findings help us understand mechanisms through which diversity boosts the stability and constancy of natural communities,” says Dr. Tuuli Rissanen, one of the first authors of the study from the University of Helsinki’s Faculty of Biological and Environmental Sciences. “They also help us identify communities that are particularly sensitive to environmental change, allowing us to target conservation measures where they are most effective in curbing biodiversity loss and safeguarding ecosystem services,” adds Dr. Arthur Rodrigues, also a first author of the study.
“For our research, it’s invaluable to have nationwide datasets that include observations on hundreds of species collected over several decades by both professionals and dedicated volunteers. These long-term, large-scale data allow us to uncover ecological processes that would remain hidden if we focused only on individual species or short time series,” adds Professor Anna-Liisa Laine, Director of the Research Centre for Ecological Change.
Fact box:
Biodiversity and natural capital
The role of biodiversity in maintaining ecosystem stability is a classic hypothesis in ecology, and a key assumption at the core of the natural capital concept. The concept sees diversity as capital that maintains ecosystem services, thus laying the foundation for human wellbeing and economy. In this study, the validity of the hypothesis was investigated in natural populations of hundreds of species, using the unique Finnish longitudinal datasets. The findings confirm the validity of this principle broadly in nature.
Functional diversity
Functional diversity is a key factor stabilising natural communities. The functional traits of species refer to their physical appearance, or morphology, physiology, behaviour, growth, reproduction, survival and resource use. Functional diversity measures the diversity of species’ functional traits.