Marine climate biogeography
One of my main areas of interest is biogeography - where do we find marine species, what are the factors that control their distribution, and where might we find them in the future?
Future projections for the Bering Sea
Goodman, Reum, Barnes, Punt, Ianelli, McHuron, De Leo, & Holsman (2025). Climate covariate choice and uncertainty in projecting species range shifts: A case study in the Eastern Bering Sea, Fish and Fisheries
As a subarctic ecosystem at the sea ice margin, the eastern Bering Sea (EBS) is warming faster than much of the global ocean, resulting in the rapid redistribution of key fishery and subsistence resources. In this project, we used species distribution models (SDMs) to assess the relationship between spatiotemporal environmental variation and the prevalance and abundance of several species of groundfish and crabs in the EBS, and to model potential future changes in their distributions. While many approaches projecting marine species range shifts have incorporated the effects of temperature on movement, there is a need to incorporate a wider suite of ecologically relevant predictors as temperature-based SDMs can considerably under- or over-estimate the rate of species responses to climate shocks.
To support long-term planning and adaptation, we combined 40+ years of scientific surveys with a high-resolution oceanographic model to examine the effects of bottom temperature, oxygen, pH and a regional climate index (the extent of the EBS ‘cold pool’) on range projections through the end of the century. We use multimodel inference to partition uncertainty among earth systems models, climate scenarios and distribution model parameterizations for several ecologically and economically important EBS groundfish and crabs.
We found that covariate choice was the primary source of uncertainty for most species, with models that account for spatial responses to the cold pool performing better and suggesting more extensive northward movements than alternative models. Models predicted declines in the probability of occurrence at low pH and oxygen concentrations for most species. We project shifts that are directionally consistent with, yet larger than those previously estimated for most species, suggesting that accounting for large-scale climate variability in species distribution models may substantially alter range projections.
Patterns in species ranges across temperate seas
Goodman, Hannah, & Ruttenberg (2019). The relationship between geographic range extent, sea surface temperature and adult traits in coastal temperate fishes, Journal of Biogeography
Many of the classic questions in biogeography concern not just the factors that control the ranges of individual species, but why species ranges are so different in the first place - why are some species observed across huge swaths of the global ocean, while (at the other extreme) some can only be found within a single estuary? Clearly there’s no one answer to this question, but as the availability of high-quality data on species ranges and biology has increased, studies have begun to assess these patterns on a global scale. For our contribution to this question, we used data on over 1,200 temperate coastal fishes to assess the role of both environmental gradients (in sea surface temperature) that can form “soft” biogeographic barriers for marine species, and biological traits (such as body size) that can impact the ability of species to establish and persist in habitats and “fill out” their potential range.
We found strong positive relationships between the number of species northern range endpoints and the steepness of the latitudinal sea surface temperature gradient on the western margins of the Atlantic and Pacific Oceans, but no relationship on the eastern margins of these ocean basins. Our results suggest that sharp latitudinal temperature gradients may pose a barrier to dispersal and range expansion along the western margins of the Atlantic and Pacific Oceans, but not necessarily on the eastern margins.
The strongest predictors of range extent in a global model are ocean basin/margin and depth range, but maximum body length, schooling behavior and use of multiple habitats are also significant predictors of range extent in the global model. We found that the factors influencing range extent differ by basin and margin - which makes sense, because variation in the strength of environmental gradients among ecosystems can mean that traits which are limiting in some basins aren’t in others.