Dinard Herbarium: A Source of Information to Infer Temporal Changes in Seaweed Communities?

Abstract

Recent changes in seaweed communities due to rapid shifts of their environment have been largely documented in temperate waters; however, long-term studies are much scarcer. In this study, we investigated the potential of Dinard Herbarium to inform us on temporal changes in seaweed communities of Brittany since the second half of the 19 th century. From nearly 3000 specimens collected in France, we identified and, when possible, corrected taxonomic and localisation errors usually encountered in unchecked natural history collections therefore minimising data inaccuracies. This original study aimed to describe the temporal dynamics of this collection and discuss the relevance of Dinard Herbarium in assessing temporal changes in seaweed communities of Brittany. The use of herbaria to assess spatio-temporal changes of seaweed biodiversity is limited, and to our knowledge, this is the first study trying to investigate this potential in the European Atlantic. This work presents new perspectives for inferring temporal changes of seaweed biodiversity.

Exploring the Influence of Temperature on Aspects of the Reproductive Phenology of Temperate Seaweeds

“…Also, additional caution needs to be taken with herbarium data because temporal patterns might be confounded by sampling bias, spatial patterns, (e.g., more records and taxa are collected closer to major research centers than at any other location, and haphazard collections tend to occur closer to the summer during periods of good weather), and/or decadal variation of local temperatures. An analysis of the Dinard Herbarium in France demonstrated such bias with its algal collection reflecting changes in laboratory locations and differences in sampling strategies (exhaustive approach = few specimens for many taxa as possible vs. biocenotic approach = many specimen from different habitat for common taxa only) (Robuchon et al, 2016).…”