Mapping present and future potential distribution patterns for a meso‐grazer guild in the Baltic Sea

Abstract

AimThe Baltic Sea is one of the world's largest semi-enclosed brackish water bodies characterized by many special features, including endemic species that may be particularly threatened by climate change. We mapped potential distribution patterns under present and future conditions for a community with three trophic levels. We analysed climate-induced changes in the species' distribution patterns and examined possible consequences for the chosen food web.LocationBaltic Sea and northern Europe.MethodsWe developed two open-source workflow-based analytical tools: one for ecological niche modelling and another for raster layer comparison to compute the extent and intensity of change in species' potential distributions. Individual ecological niche models were generated under present conditions and then projected into a future climate change scenario (2050) for a food web consisting of a guild of meso-grazers (Idotea spp.), their host algae (Fucus vesiculosus and Fucus radicans) and their fish predator (Gasterosteus aculeatus). We used occurrence data from the Global Biodiversity Information Facility (GBIF), literature and museum collections, together with five environmental layers at a resolution of 5 and 30 arc-minutes.ResultsHabitat suitability for Idotea balthica and Idotea chelipes in the Baltic Sea seems to be mostly determined by temperature and ice cover rather than by salinity. 2050 predictions for all modelled species show a northern/north-eastern shift in the Baltic Sea. The distribution ranges for Idotea granulosa and G. aculeatus are predicted to become patchier in the Baltic than in the rest of northern Europe, where the species will gain more suitable habitats.Main conclusionsFor the Baltic Sea, climate-induced changes resulted in a gain of suitable habitats for F. vesiculosus,I. chelipes and I. balthica, whereas lower habitat suitability was predicted for I. granulosa,F. radicans and G. aculeatus. The predicted north-eastern shift of I. balthica and I. chelipes into the distribution area of F. radicans in the Baltic Sea may result in increased grazing pressure. Such additional threats to isolated Baltic populations can lead to a higher extinction risk for the species, especially as climate changes are likely to be very rapid.

Evaluating the potential of ecological niche modelling as a component in marine non-indigenous species risk assessments

“…Among them is the fact that model shapes produced by this algorithm are n-dimensional ellipsoids, better reflecting the principle of central tendency in niche theory (Farber and Kadmon, 2003) and matching convex representations as hypothesized by Soberón and Nakamura (2009). Additionally, only presence points are required, with no need to generate pseudo-absence or background points, therefore not requiring prior knowledge of the species' origin and dispersal ability for model calibration, according to a recent study (Barve et al, 2011) (see also Leidenberger et al, 2015 for more information). Models were created using each species´maximum distribution range and then projected into the North East Atlantic area.…”

“…For more information on the ENM workflow see Leidenberger et al (2015). We used the Mahalanobis distance method (Mahalanobis, 1936;Farber and Kadmon, 2003) by means of the openModeller Environmental Distance algorithm (Muñoz et al, 2011).…”

“…At present, low temperatures prevent numerous NIS from establishing in the colder Baltic Sea or Northern Europe, where large areas are covered with ice in winter. But this may change in future (Meier et al, 2012) and ENMs based on future climate models can play an important role in RAs in the future (Jones et al, 2013;Leidenberger et al, 2015), to forecast the effects of climate change on the establishment of NIS.…”

“…It allows us to predict suitable habitats and forecast distribution changes using future climate models (Jones et al, 2013;Leidenberger et al, 2015). Today, important environmental raster data for benthic marine environments are still lacking to further improve ENM (e.g.…”

High climate velocity and population fragmentation may constrain climate‐driven range shift of the key habitat former Fucus vesiculosus

“…However, due to the coarse resolution of the global models, they are often not suitable for studies of regional conditions, while higher resolution models can give a more correct representation of air temperature, wind patterns and precipitation. Thus, it is not surprising that the projections of Assis, Serrão, Claro, Perrin, and Pearson () and Leidenberger, De Giovanni, Kulawik, Williams, and Bourlat () came to a different conclusion with a moderate increase in the future distribution of F. vesiculosus within the Baltic Sea. The simulated increase in these studies was mainly driven by an increase in temperature.…”