ABSTRACT: Orientation of sandhoppers at different points along a dynamic shoreline in southern Tuscany
Scapini F., Chelazzi L., Colombini I., Fallaci M. and Fanini L. 2005.
Orientation of sandhoppers at different points along a dynamic shoreline in southern Tuscany.
Marine Biology 147: 919-926.
Orientation experiments were carried out on Talitrus saltator (Crustacea Amphipoda) at four points along three kilometres on a dynamic sandy beach inside the Maremma Regional Park (Grosseto, Italy) to highlight behavioural variation related to distance from river mouth, to erosion or accretion of shoreline and to human trampling on the beach. Tests were performed using circular transparent Plexiglas arenas, contemporaneously at the four points. Replicates were made in two different months (September 2002 and May 2003), on two-three successive days, in the morning and afternoon. The distributions of the angles of orientation were compared for the different points and seasons, and multiple regression analyses were performed to test the effects of environmental and intrinsic variables on orientation. Sandhoppers showed the highest scatter at the eroded shoreline, intermediate scatter at the accreting beach most distant from the river mouth, and consistent orientation seaward in the least disturbed point. Orientation of sandhoppers was significantly affected by season, global radiation, time of day, distance from the river mouth and human trampling. Sex and air humidity were of minor significance in the multiple regression model. The results, on one hand, confirm plasticity in orientation of sandhoppers living on a dynamic shoreline, and on the other hand, show that variation in orientation could potentially be used as a bioindicator of shoreline changes.
Addresses of the authors:
Felicita Scapini, Dipartimento di Biologia Animale e Genetica “Leo Pardi”, Università di Firenze, via Romana 17, 50125 Firenze, Italy
Lucia Fanini, Dipartimento di Biologia Animale e Genetica “Leo Pardi”, Università di Firenze, via Romana 17, 50125 Firenze, Italy
Lorenzo Chelazzi, Isabella Colombini and Mario Fallaci, Istituto per lo Studio degli Ecosistemi, Sezione di Firenze, Florence, Italy