Lessons from the macroinvertebrates: species‐genetic diversity correlations highlight important dissimilar relationships

Abstract

Summary Species and genetic diversity patterns are predicted to co‐vary due to similar mechanistic processes. Previous studies assessing species and genetic diversity correlations (SGDCs) have focused primarily on local diversity patterns or island‐like systems and ignore the underlying dispersal network. Here we assessed local and regional SGDCs using freshwater macroinvertebrates sampled across the Rhine river network, a spatially large and highly connected system, in Switzerland. We utilised a set of polymorphic microsatellite markers to assess the genetic diversity of two amphipod species of the Gammarus fossarum complex, which were compared to species level diversities of Amphipoda, Ephemeroptera, Plecoptera, Trichoptera and family level macroinvertebrate diversity across 217 randomly selected sites. All sites were selected based on a representative and standardised species‐sampling scheme. We analysed within site (α‐SGDC) and between‐site SGDC (β‐SGDC). Against our expectation, we generally found negative or null α‐SGDCs and β‐SGDCs. However, we did find genetic diversity to be spatially structured, whereas species richness was related to local environmental factors. These findings suggest that the genetic and species levels of diversity observed are driven by different mechanisms (e.g., environment versus demography), or operate across different temporal or spatial scales (e.g., colonisation history or dendritic river network structure), and may be attributed to differences in the species' ecology or life history. Overall, conservation measures in riverine systems aiming at only one level of diversity may not necessarily benefit other levels of diversity.

Lessons from the fish: a multi‐species analysis reveals common processes underlying similar species‐genetic diversity correlations

“…Additionally, high inter‐specific variability in α‐SGDCs has recently been theoretically explained (Laroche et al ., ). However, our results are consistent with previous findings showing that similar positive α‐SGDCs are detected when species and genetic α‐diversity are extracted from ecologically similar taxonomic groups (He & Lamont, ; Seymour et al ., ). For instance, in a companion paper involving invertebrates across a large river basin, Seymour et al .…”

“…For instance, in a companion paper involving invertebrates across a large river basin, Seymour et al . () found that α‐SGDC was stronger when intraspecific genetic α‐diversity of Gammarus sp. was compared to species α‐diversity of Amphipoda than to other invertebrate taxa, such as Ephemeroptera, Plecoptera or Trichoptera.…”

“…In a companion article, Seymour et al . () provides complementary findings of patterns and processes of SGDC in DRNs, but focusing on a taxonomic group (invertebrates) whose dispersal is not restricted to water corridors.…”

Geomorphic influence on intraspecific genetic differentiation and diversity along hyporheic corridors

“…This hypothesis opens the door for empirical studies that explore whether parallel geomorphic processes can drive spatial patterns of species and genetic diversity, thereby resulting in species‐genetic diversity correlations among hyporheic corridors (see, e.g. Fourtune, Paz‐Vinas, Loot, Prunier, & Blanchet, ; Seymour, Seppälä, Mächler, & Altermatt, ; Vellend et al., ).…”

A cost‐and‐time effective procedure to develop SNP markers for multiple species: A support for community genetics

“…For instance, positive relationships between intraspecific genetic diversity and local species richness could be observed within an ecosystem and is referred to as species–genetic diversity correlation (SGDC, Lamy, Laroche, David, Massol, & Jarne, ; Vellend & Geber, ). Although the underlying mechanisms of SGDC have not been fully elucidated yet, examples from freshwater fish (Fourtune, Paz‐Vinas, Loot, Prunier, & Blanchet, ), macroinvertebrates (Seymour, Seppälä, Mächler, & Altermatt, ), or a coral reef community (Selkoe et al., ) have highlighted the interest of studying SGDC for conservation perspectives, particularly in systems facing anthropogenic or natural disturbances (Evanno, Castella, Antoine, Paillat, & Goudet, ; Frey et al., ). Likewise, life‐history traits are worthy of interest to explain neutral patterns of genetic diversity (Ellegren & Galtier, ; Romiguier et al., ).…”