Abstract
Benthic suspension feeding mussels are an important functional guild in coastal and estuarine ecosystems. To date we lack information on how various environmental gradients and biotic interactions separately and interactively shape the distribution patterns of mussels in non-tidal environments. Opposing to tidal environments, mussels inhabit solely subtidal zone in non-tidal waterbodies and, thereby, driving factors for mussel populations are expected to differ from the tidal areas. In the present study, we used the boosted regression tree modelling (BRT), an ensemble method for statistical techniques and machine learning, in order to explain the distribution and biomass of the suspension feeding mussel Mytilus trossulus in the non-tidal Baltic Sea. BRT models suggested that (1) distribution patterns of M. trossulus are largely driven by separate effects of direct environmental gradients and partly by interactive effects of resource gradients with direct environmental gradients. (2) Within its suitable habitat range, however, resource gradients had an important role in shaping the biomass distribution of M. trossulus. (3) Contrary to tidal areas, mussels were not competitively superior over macrophytes with patterns indicating either facilitative interactions between mussels and macrophytes or co-variance due to common stressor. To conclude, direct environmental gradients seem to define the distribution pattern of M. trossulus, and within the favourable distribution range, resource gradients in interaction with direct environmental gradients are expected to set the biomass level of mussels.
Highlights
A key mission in ecology is to understand biotic patterns and their changes in nature
boosted regression tree modelling (BRT) models suggested that (1) distribution patterns of M. trossulus are largely driven by separate effects of direct environmental gradients and partly by interactive effects of resource gradients with direct environmental gradients
The generic results of our study are that direct environmental gradients seem to define the distribution pattern of the suspension feeding bivalve M. trossulus and within the favourable distribution range, the resource gradient is expected to have an important role in shaping the biomass distribution of M. trossulus
Summary
A key mission in ecology is to understand biotic patterns and their changes in nature. A suitable habitat is often defined by complex interrelationships among a multitude of environmental variables that can be largely divided into three broad categories [4]. These include indirect environmental gradients, resource gradients and direct environmental gradients. Water movement can indirectly affect the habitat of suspension feeding bivalves by modifying sedimentation rates or affect sessile mussels directly by physically disturbing or detaching animals [1,7]. Thereby, water movement can impact benthic suspension feeders through a third pathway, by modifying the resource supply while limiting the amount of food reached by mussels [8,9]
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have