Habitat stability modulates temporal β-diversity patterns of
seagrass-associated fauna across biogeographical scales
Abstract
Aim Identifying drivers that shape biodiversity across biogeographical
regions is important to predict ecosystem responses to environmental
changes. While beta diversity has been widely used to describe
biodiversity patterns across space, the dynamic assembly of species over
time has been comparatively overlooked. Insights from terrestrial and
marine studies on temporal beta diversity has mostly considered
environmental drivers, while the role of biotic mechanisms has been
largely ignored. Here, we investigated patterns of temporal variation in
beta diversity of seagrass-associated animals (amphipods, as model
organisms). Location We conducted a study in three biogeographical
regions across a temperate to subtropical latitudinal gradient
(approximately 2,000 km, 13º of latitude). In each region, we randomly
selected three C. nodosa meadows, totalling nine meadows sampled
seasonally (i.e., four times per year) from 2016 to 2018. Methods We
partitioned temporal beta diversity into its turnover (i.e. species
replacement) and nestedness (i.e. differences in species composition
caused by species losses) components and addressed the relative
influence of both temporal variation in habitat structure (i.e., biotic
driver) and environmental conditions on such patterns. Results Our study
revealed high temporal beta diversity of amphipod assemblages across the
three biogeographical regions, denoting significant fluctuations in
species composition over time. We identified species turnover as the
primary driver of temporal beta diversity, strongly linked to temporal
variability in local habitat structure rather than regional climatic
drivers. Subtropical Atlantic meadows with high structural stability
over time exhibited the largest turnover rates compared with temperate
Mediterranean meadows, under lower structural stability, where
nestedness was a more relevant component of temporal beta diversity.
Main conclusions Our results highlight the crucial role of habitat
stability in modulating temporal beta diversity patterns on animals
associated with seagrasses, stressing its importance for developing
management and restoration actions in the context of diversity loss and
fragmentation of ecosystems.