ECR feature: Tobi Oke on data synthesis as a diagnostic tool for capturing biodiversity problems

Tobi is a post-doctoral fellow at University of Saskatchewan and Wildlife Conservation Society, Canada. He is interested in assessing species distributions and vulnerability in relation to climate change and natural disturbance. Here, Tobi shares his perspetive on quantifying biodiversity change in relation to data gathering tools.

Tobi during a fieldwork to explore how fish use seagrass beds following disturbance (Stredman Island, Gulf of Mexico, Aransas Pass, Texas United States)

Institute. Wildlife Conservation Society Canada & University of Saskatchewan, Saskatoon.

Academic life stage. Postdoc.

Recent JBI paper. Oke, T. A., Zhang, S. Y., Keyser, S. R., & Yeager, L. A. (2022). Sea‐surface temperature anomalies mediate changes in fish richness and abundance in Atlantic and Gulf of Mexico estuaries. Journal of Biogeography 49(9), 1609-1617.

Data synthesis as a diagnostic tool for capturing biodiversity problems. Evaluating biodiversity change is becoming a valuable diagnostic tool for capturing the impacts of global change on our ecosystems. We now have data gathering tools (e.g., biodiversity databases) and open-source programming and computational platforms that allow for data processing, analytics and visualization at a scale that we are still beginning to appreciate. While this area of research is exciting, it also presents us with a new set of debates that extends our traditional views about ecological concepts and scale-dependent effects in ecology and biogeography. In particular, how should we quantify biodiversity and can we meaningfully quantify biodiversity change at a regional or global scale given data deficiencies? The latter part of the question particularly pertains to global analyses of biodiversity change because we often lack data from key biodiversity regions, namely the global south. Also for diagnostic purposes, the ultimate interest is to identify the mechanisms influencing biodiversity change rather than changes in biodiversity per se, which can be challenging.

We addressed some of these issues in our recent paper in Journal of Biogeography on the relationships between sea-surface temperature anomalies and fish diversity. Our approach was, first, to acknowledge that there are different aspects of biodiversity and thus we need complementary metrics that would capture all dimensions of biodiversity, rather than relying on richness alone. We thus explored richness, abundance and turnover patterns, and the relationships between these metrics, to get insight into different aspects of change in estuarine fish diversity. Second, we acknowledged that drivers of biodiversity are hierarchical and there can be a mismatch between the scale at which biodiversity is quantified and the scale at which different drivers may be relevant. Such conceptual mismatches perhaps underlie some of the contentions from differing analyses of biodiversity. We thus addressed this by parsing our biodiversity and environmental data into biogeographic boundaries, which helped with some of the patterns that we described in the paper. Specifically, using long-term fisheries independent surveys that comprised over 500 fish species and over 30 million individual fish, we showed that species richness, abundance and turnover have increased across the Atlantic and Gulf of Mexico estuaries since the 1980s. These changes were due to sea-surface temperature anomalies, especially in the more northern estuaries where ocean warming has been pronounced. Also, contrary to the poleward range shifts that have been documented in marine systems, we found strong bidirectional range shifts among estuarine fish species. We attributed the southward movements of species to periods of cooling, which we detected in the sea-surface temperature anomalies for southern estuaries. The various insights derived from this study were far beyond what we could have imagined from only looking at a subset of the data.

Perhaps the less appreciated but most important aspect of our study was data gathering. The success of our study, and of other similar ones, depends on the efforts of field biologists and researchers across different institutions. Further, acquiring the kind of data required for biodiversity synthesis is often expensive, especially in marine systems and less adaptable to citizen science. More so, many of these data were collected for non-academic purposes and often by small government departments. Thus, the data are often hidden and rarely deployed beyond their original purposes, especially if they have not been included in a published document. For these reasons, pulling data from primary sources and compiling them into usable formats can be laborious. There can also be resistance to data sharing in some places, which in our experience has derailed the implementation of similar research ideas. Although journals like the Journal of Biogeography, through their data sharing policies, have been instrumental in putting some of these data into public places, those captured are still a fraction of what is out there because most of these data were gathered by non-academics and for non-academic purposes. At the same time, most of these long-term surveys were public-funded. Perhaps government and funding agencies can take a lead to ensure that data from public-funded programs are routinely archived in public places. To my knowledge, there are currently no such requirements. This would also entail developing data gathering infrastructure, especially for time-series data. Sensitive data such as those involving endangered and species at risk can be handled on an individual basis. There is no doubt that large-scale quantitative protocols would be a part of the tools for addressing the issue of dwindling biodiversity across the globe. But progress would depend on changes in attitude toward data sharing.

Tobi during a helicopter ride for a climate refugia project in Northern Yukon, Yukon Territory, Canada.

Published by jbiogeography

Contributing to the growth and societal relevance of the discipline of biogeography through dissemination of biogeographical research.

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