Disentangling patterns in population parameters of the wedge clam Donax hanleyanus from sandy beaches of Argentina: The role of environmental variability

Unravelling the role of local and large-scale factors in structuring sandy beach populations: the wedge clam Donax hanleyanus

“…Oceanic beaches harbored a population structure fully represented by all size classes and higher body size than estuarine beaches. Similar macroscale patterns were detected for this species on the Argentinean coast (Risoli et al 2022) and for other macrofaunal species on Uruguayan beaches (Celentano et al 2010, Lozoya et al 2010. Freshwater runoff also affected D. serra abundance and population structure on a South African beach (Schoeman & Richardson 2002).…”

“…Worldwide macrofaunal patterns highlight the role of local morphodynamic features as explanatory variables of species richness, abundance and biomass, which increase toward wide dissipative beaches with gentle slopes and finegrain sands (Defeo & McLachlan 2013, Barboza & Defeo 2015. Oceanographic fronts, upwellings, primary production and estuarine discharges, operating at several temporal and spatial scales, also play pivotal roles as predictors of macrofaunal diversity and abundance on sandy shores (Gray 2016, Defeo et al 2017, Risoli et al 2022.…”

“…These predictions have been successfully tested in intertidal beach-type generalist species (sensu McLachlan & Defeo 2018) that can colonize a wide spectrum of morphodynamic conditions (Celentano & Defeo 2006, Corte et al 2014. However, in estuarine environments, local physical features and estuarine-related conditions affect sandy beach macrofauna in different ways that cannot be explained by only one factor (Rodil et al 2014, Carcedo et al 2015, Ortega-Cisneros et al 2017, Risoli et al 2022. Therefore, an overarching challenge in sandy beach ecology is to assess the effects of combined forces of local and regional factors on macrofauna structure, dynamics and function (Fanini et al 2020).…”

“…These bivalves are well-suited to inhabit different beach morphodynamic types (McLachlan et al , 1996. On the Atlantic coast of South America, the wedge clam D. hanleyanus Philippi, 1945 inhabits sandy beaches spanning a broad range of morphodynamic types (Defeo & McLachlan 2011), from Caravelas, Brazil (17°S;Cardoso & Veloso 2003), through Uruguay (Delgado & Defeo 2007) to Mar del Plata, Argentina (38° S; Risoli et al 2022). The Uruguayan coastline is characterized by microtidal sandy beaches with a wide variety of morphodynamic features, including transitional environments influenced by the Rio de la Plata (RdlP) estuary, which is the widest estuary in the world and strongly influences coastal marine waters (Piola et al 2005, Lercari & Defeo 2006.…”

Testing macroecological hypotheses in sandy beach populations: the wedge clam Donax hanleyanus in South America

“…Latitudinal patterns in life-history traits have been observed in a broad range of intertidal organisms (Dugan et al 1994, Defeo & McLachlan 2005, Mc -Lachlan & Defeo 2018, including bivalves that dominate sandy-beach biota (Cardoso & Veloso 2003, Fiori & Defeo 2006, Moss et al 2016). These species also exhibit higher individual growth rates and lower longevity with increasing SSTs (Marquardt et al 2022), and a reduced abundance, survival, growth, and fecundity in beaches affected by large-scale salinity gradients (Schoeman & Richardson 2002, Risoli et al 2020, Celentano et al 2022 or low food availability (Risoli et al 2022). Concerning the role of local morphodynamics, a negative impact on life-history traits is expected in populations inhabiting reflective beaches compared to dissipative ones, according to the habitat harshness hypothesis (HHH).…”