DOI: 10.5061/dryad.ngf1vhj0k
title: Data from: Enigmatic freshwater mussel declines could be explained by the biodiversity-disease relationship

description: The biodiversity-disease relationship states that increased species
 richness leads to lower pathogen pressure (i.e., the dilution effect), an
 effect that erodes with biodiversity loss. However, whether losses of the
 dilution effect can trigger extinction cascades remains largely
 unexplored. To explore this idea, we consider declines in freshwater
 mussels, on average the most threatened non-marine group of organisms in
 the world. We argue that anthropogenically-stimulated declines in mussel
 richness amplify pathogens in remaining species. Pathogen amplification
 triggers further local losses in both mussel abundance and richness,
 explaining the observed so-called “enigmatic” declines in freshwater
 mussels.  Vulnerable communities could become trapped in cycles
 of pathogen amplification and host decline. We highlight knowledge gaps
 and provide key steps to assess the likelihood of this occurring; these
 key steps are applicable to any host group.  Policy implications.
 Our argument constitutes a testable hypothesis that may explain richness
 or abundance declines in previously intact communities. We provide further
 impetus for the consideration and preservation of diversity at a local
 scale, and show that effective conservation requires integration of both
 host and parasite ecology.
description: This dataset is based on a review of host-parasite interactions
 in the freshwater mussel families Unionidae and Margaritiferidae,
 originally carried out according to Brian & Aldridge (2019,
 <em>Biological Conservation</em> 237, 155-165) and refined and
 described in detail in Brian & Aldridge
 (2022, <em>Conservation Biology</em> 36, e13979). It consists
 of a column of mussel host species, and all parasites previously recorded
 as being associated with that host species.
description: Microsoft office and R software are required to process these
 data files.
description: # Data from: Enigmatic freshwater mussel declines could be explained by
 the biodiversity-disease relationship --- ### Background: This dataset is
 based on a literature review of host-parasite interactions in the
 freshwater mussel families Unionidae and Margaritiferidae, originally
 carried out according to Brian & Aldridge (2019, Biological
 Conservation 237, 155-165) and refined and described in detail in Brian
 & Aldridge (2022, Conservation Biology 36, e13979). It consists of a
 column of mussel host species, and all parasites previously recorded as
 being associated with that host species. Parasite taxa are limited to the
 four main groups of freshwater mussel parasites (digenean trematodes,
 aspidogastrean trematodes, mites, ciliates). The current submission is
 limited to the data required to replicate results in the present study
 (Journal of Applied Ecology, 2023); other data files are available in
 Brian & Aldridge (2019, 2022). --- ### Data description and file
 structure: The data consists of two files: supplementary_data_1.csv *
 Column 1 (Host) contains freshwater mussel species. * Column 2 (Parasite)
 contains a list of every parasite that have been recorded as being
 associated with that mussel species. Therefore, if a mussel species has
 multiple parasites recorded, the mussel species will occur multiple times
 in Column 1; similarly, if a parasite is recorded from multiple mussel
 species then the parasite will occur multiple times in Column 2.
 supplementary_code_1.R * Describes how to use the file
 supplementary_data_1.csv to produce Fig. 1a in the main manuscript. ---
 ### Sharing and access information: The dataset is also publicly available
 attached as supplementary information to the following article: Brian, J.
 I., & Aldridge, D. C. (2022). Mussel parasite richness and risk of
 extinction. Conservation Biology, 36(6), e13979.
 Comprehensive data from the
 original literature review (Brian & Aldridge 2019) is also publicly
 available as Tables A1.2 and A1.3 in the thesis of Joshua Brian: Brian, J.
 (2022). Parasites in freshwater mussels: community ecology and
 conservation (Doctoral dissertation, University of Cambridge).