Spatio-temporal variability of benthic macrofauna in a coastal lagoon assessed by ecological interaction networks

Abstract

An ecological survey of the benthic communities was carried out, at both spatial and temporal scales, in Papapouli Lagoon, the first ecotouristic park in Greece by applying for the first time, ecological network analysis. The application of ecological network analysis provided novel information on the quality of interactions among species, undetected by the most frequently used methods. The sorting of substrate samples enabled the identification and density determination of 40,036 individuals belonging to 31 different taxa, although, strong dominance of only a few species was observed. "Deposit feeders" were the dominant trophic group in all sampling sites and seasons while "suspension feeders" exhibited relatively the lowest abundance. The periodic opening of the sea inlet seems to be of crucial importance. In coastal lagoons, where there is constant communication with the sea, benthic fauna patterns seem to change according to the sea-land gradient. However, in intermittently closed lagoons, such as Papapouli Lagoon, a more homogenous pattern is evident. The obtained networks showed that when communication with the sea is interrupted all the benthic fauna patterns tend to be destabilized and centralized around one species, which in most cases is a "deposit feeder". When the inlet opens and communication with the sea is restored, the benthic composition seems to be more cohesive, especially in the most distant regions. Knowledge generated by network analysis should provide a valuable tool in order to assess potential environmental changes and assist management decisions.

<i>Callinectes sapidus</i> Rathbun, 1896 (Brachyura: Portunidae): An assessment on its diet and foraging behaviour, Thermaikos Gulf, NW Aegean Sea, Greece: Evidence for ecological and economic impacts

“…The small inlet is almost always closed only under extreme conditions opens, the large inlet is periodically open (June-December). Wind direction and intensity are affecting the opening/closing of the large inlet (Paraskevopoulou et al, 2015). These condi-tions dictate a seasonality in sediment and sea water availability.…”

“…Seaweed sifting. Seaweeds in Papapouli Lagoon support a variety of taxa, such as amphipods and isopods (Paraskevopoulou et al, 2015), mysids (Nikolopoulou et al, 2013b), and larvae and sub-adult decapods (Nikolopoulou et al, 2013a). Blue crabs were observed to prey on these invertebrates using a sifting strategy: holding seaweeds to their mandibles and systematically manipulating the material (Fig.…”

Morphometric Relationships of the Global Invader Callinectes sapidus Rathbun, 1896 (Decapoda, Brachyura, Portunidae) from Papapouli Lagoon, NW Aegean Sea, Greece. with Notes on Its Ecological Preferences

“…Papapouli Lagoon is a chocked lagoon with two points of contact with the sea. The small inlet is almost always closed-it is open only under extreme conditions-and the large inlet is periodically open (June-December)-this is affected by the wind's direction and intensity [40]. The large central canal is 30 m long and 15-45 m wide, depending on weather conditions [41].…”

Neighbourhood benthic configuration reveals hidden co-occurrence social diversity

“…Unfortunately, these interactions have been overlooked since traditional methods of estimating benthic biodiversity [7,8] focus on counting the number of species and individuals within a transect (alpha diversity) and then analysing the differences and trends across sites and regions [6,9]. Studies with a specific focus on interactions have concentrated on isolated pairwise relationships, such as mutualism [10] and competition [11][12][13], and between specific species [14,15].…”