Taking into account uncertainties should be a mandatory aspect to include in the viability analysis of populations

Disentangling effects of uncertainties on population projections: climate change impact on an epixylic bryophyte

Alejandro Ruete,Wei Yang,Lars Bärring,Nils Chr. Stenseth andTord Snäll

Published online before print March 28, 2012, doi:10.1098/rspb.2012.0428Proc. R. Soc. B

Assessment of future ecosystem risks assumes great significance against the backdrop of climate change. This assessment should take in to account relevant uncertainty sources. Studying joint effects of climate variables and using modelling techniques that allow proper treatment of uncertainties becomes imperative.

Here the researchers investigated the influence of three of the IPCC's scenarios of greenhouse gas emissions (special report on emission scenarios (SRES)) on projections of the future abundance of a bryophyte model species. They also compared the relative importance of uncertainty sources on the population projections.

According to the researchers the whole chain global climate model (GCM)—regional climate model—population dynamics model is addressed. The researchers say uncertainty depends on both natural- and model-related sources, in particular on GCM uncertainty. Ignoring the uncertainties gives an unwarranted impression of confidence in the results. The researchers affirm that most likely population development of the bryophyte Buxbaumia viridis towards the end of this century is negative. Even with a low-emission scenario, there is more than a 65 per cent risk for the population to be halved.

The conclusion of a population decline is valid for all SRES scenarios investigated. The researchers say uncertainties are no longer an obstacle, but a mandatory aspect to include in the viability analysis of populations.