Artificial light at night may increase the predation pressure in a salt marsh keystone species

NUÑEZ, J.D.; BAS, C.C.; PÉREZ GARCÍA, M.; OCAMPO, E.H.; RIBEIRO, P.D.; LUPPI, T.A.

MARINE ENVIRONMENTAL RESEARCH

ELSEVIER SCI LTD

Año: 2021 vol. 167

0141-1136

Artificial light at night (ALAN) has the potential to alter ecological processes such as the natural dynamics ofpredator-prey interactions. Although understanding of ALAN effect on faunal groups has increased in recentyears, few studies have explicitly tested for direct consequences of ALAN on predator-prey systems. Here, weevaluated the effect of ALAN on juvenile mortality due to cannibalism and general predation of the SouthAmerican intertidal burrowing crab Neohelice granulata, a key ecosystem engineer of salt marshes. For this, weconducted tethering and crab enclosure experiments for both night and day periods during successive tidal floodsin a semidiurnal tidal regime. Both experimental approaches were deployed simultaneously in the field and theylasted four consecutive days during new moon nights. ALAN was simulated by a white LED lamp (30W) with asolar panel as a source of power in five separated areas selected as replicates. For general predation, juvenilesurvival under ALAN was 44% lower than during the daytime and 61% lower than under natural dark conditions.For cannibalism, juvenile survival under ALAN and during the daytime was similar and about 30% lower thanunder natural dark conditions. We also found that the abundance of adult male crabs (cannibals) under ALANwas nearly five times higher than at natural dark conditions. Our field experiments provide evidence that ALANcan increase the mortality of juvenile crabs and is at least partially driven by cannibalistic interactions.