Functional diversity loss and taxonomic delays of European freshwater fish and North American Breeding birds

Lucie Kuczynski, Ana Maria Bastidas Urrutia, Helmut Hillebrand

This is a plain language summary of a Functional Ecology research article which can be found here.

We looked at how biodiversity in ecosystems changes over time by focusing on the arrival of new species and the departure of old ones from a given habitat, using data on freshwater fish from the RivFishTime database and breeding birds from the American Breeding Bird Survey.

We found that new species may not possess as many novel characteristics as expected based on random dynamics. This could result in the collapse of the ecosystem (i.e., loss of ecosystem services) over the long run as species are not diverse enough. This result challenges the idea that ecosystems can quickly adapt to environmental changes, such as climate change or habitat alterations, with a community composition shift. Although new species can help to restore the deficit in unique species characteristics found in a given habitat, an overabundance of similar species can also hinder the ecosystem’s ability to cope with environmental fluctuations.

To protect species and their ecosystems, it is crucial to understand their characteristics and how they change over time and across space. Novel indices are being developed to better grasp the changes in diversity over time.

The number of species found in a community may be uncorrelated to the number of unique features (i.e., functional traits) found in this community. Given the observed changes in the number of species (i.e., taxonomic diversity) and the lack of a corresponding increase in functional diversity (i.e., accounting for functional traits), it can be expected that the temporal dynamics of functional diversity will also show specific patterns, which may not be predictable from the trends in taxonomic diversity (Credit: the authors)