Abstract
AbstractThe notion that closely related species resemble each other in ecological niche space (i.e., phylogenetic dependence) has been a long‐standing, contentious paradigm in evolutionary biology, the incidence of which is important for predicting the ecosystem‐level effects of species loss. Despite being examined across a multitude of terrestrial taxa, many aspects of niche conservatism have yet to be explored in marine species, especially for characteristics related to resource use and trophic behavior (Eltonian niche characteristics, ENCs). We combined ENCs derived from stable isotope ratios at assemblage‐ and species‐levels with phylogenetic comparative methods, to test the hypotheses that benthic marine fishes (1) exhibit similar assemblage‐wide ENCs regardless of geographic location and (2) display phylogenetically dependent ENCs at the species level. We used a 12‐species sub‐set of the monophyletic group Rajidae sampled from three independent assemblages (Central California, Gulf of Alaska, and Northwest Atlantic), which span two ocean basins. Assemblage‐level ENCs implied low trophic diversity and high evenness, suggesting that Rajidae assemblages may exhibit a well‐defined trophic role, a trend consistent regardless of geographic location. At the species level, we found evidence for phylogenetic dependence of ENCs relating to trophic diversity (i.e., isotopic niche width; SEAc). Whether individuals can be considered functional equivalents across assemblages is hard to ascertain because we did not detect a significant phylogenetic signal for ENCs relating to trophic function (e.g., trophic position). Thus, additional, complimentary approaches are required to further examine the phylogenetic dependence of species functionality. Our approach illustrates the potential of stable isotope‐derived niche characteristics to provide insight on macroecological processes occurring across evolutionary time, which could help predict how assemblages may respond to the effects of species loss.
Highlights
The extent to which closely related species share similar ecological characteristics, such as morphology, thermal tolerance, habitat, and diet, defined as phylogenetic niche conservatism (PNC, Cooper et al 2010), has long fascinated evolutionary biologists (Harvey and Pagel 1991, Holt and Barfield 2008, Losos 2008, Wiens et al 2010)
Skate white-muscle tissue samples from central California were collected during bottom trawl and longline surveys conducted by the National Marine Fisheries Service (NMFS) Southwest Fisheries Science Center between 2002 and 2005 (Bizzarro et al 2014)
Assemblage-level ENCs Carbon ranges were consistent and did not exceed 1.1&, but nitrogen ranges were greater for Central California (1.32&) than for Gulf of Alaska and NW Atlantic assemblages (
Summary
The extent to which closely related species share similar ecological characteristics, such as morphology, thermal tolerance, habitat, and diet, defined as phylogenetic niche conservatism (PNC, Cooper et al 2010), has long fascinated evolutionary biologists (Harvey and Pagel 1991, Holt and Barfield 2008, Losos 2008, Wiens et al 2010). Despite the proliferation of phylogenetic comparative methods, much of the published work has been limited to examining niche evolution in terrestrial fauna, such as birds (Rice et al 2003, Maldonado et al 2017), lizards (Harmon et al 2003, Knouft et al 2006), and mammals (OlallaTarraga et al 2017), with fewer attempts having been made in marine organisms, including fishes (e.g., Ingram et al 2010, Egan et al 2018) This emphasis on terrestrial fauna is likely an artifact of the logistical challenges of studying marine organisms, especially those which display complex and cryptic life histories. Considering the multitude of threats facing marine ecosystems (Cozar et al 2014, McCauley et al 2015, Molinos et al 2016), understanding how ecological niches have evolved is intricately tied to our ability to identify vulnerable taxa, predict how associated distributions and functional roles are likely to change over time, and understand how protecting specific niches may help preserve marine biodiversity (Brooker et al 2016)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
