| Title | Spatial variability and human disturbance in shallow subtidal hard substrate assemblages: a regional approach. |
| Abstract | Quantitative information about spatial patterns in subtidal hard substrate assemblages is scant. Such information is necessary to understand the responses to anthropogenic disturbances in these habitats. Along the coast of Apulia (Southern Italy), the collection of the European date mussel Lithophaga lithophagais a strong source of disturbance: harvesting is carried out by demolition of the rocky substrate and causes epibiota disappearance. A hierarchical sampling design was used to quantify the spatial variability of subtidal epibenthic assemblages and the extent of rock damage due to L. lithophagaharvesting along 360 km of rocky coasts in Apulia. The surveyed coast was divided into 8 adjacent sectors, and replicate samples were taken by visual inspection at each of the 3 sites nested in each sector. Multivariate analyses indicated that assemblages differed consistently with spatial scale, variability being higher at the largest scale. However, variability among sites within each sector was also detected. Patchiness (i.e., average similarity among quadrats) was consistent among sectors. Some species were identified as important in characterising and/or differentiating sectors. The pattern of distribution of these species as well as total cover and number of species were analysed by analysis of variance. Results recorded a considerable source of variation at site level. Damage by L. lithophagafishing was shown to be extremely widespread. A humped relationship between patchiness and disturbances by L. lithophagafisheries was obtained. In particular, patchiness at a small scale was highest at intermediate levels of damage, because disturbance produces patches of different size and/or age, leading to mosaic landscapes of epibenthic assemblages. |
| Source | Marine ecology. Progress series (Halstenbek) 212, pp. 1–12 |
| Keywords | Subtidal assemblagesSpatial scaleHuman disturbanceLithophaga lithophagaMediterrane |
| Journal | Marine ecology. Progress series (Halstenbek) |
| Editor | Inter-Research, Oldendorf/Luhe, Germania |
| Year | 2001 |
| Type | Articolo in rivista |
| Authors | Fraschetti S.1, Bianchi C.N.2, Terlizzi A.1, Fanelli G.3, Morri C.4, Boero F.1 |
| Text | 6303 2001 Subtidal assemblages Spatial scale Human disturbance Lithophaga lithophaga Mediterrane Spatial variability and human disturbance in shallow subtidal hard substrate assemblages a regional approach. Fraschetti S.1, Bianchi C.N.2, Terlizzi A.1, Fanelli G.3, Morri C.4, Boero F.1 1 Dipartimento di Biologia, Stazione di Biologia Marina di Porto Cesareo, CoNISMa, Universita di Lecce, 73100 Lecce, Italy 2 Marine Environmental Research Centre, ENEA Santa Teresa, PO Box 316, 19100 La Spezia, Italy 3 IAMC CNR, Sede Talassografico A. Cerruti, Via Roma 4, 74100 Taranto, Italy 4 DipTeRis, Dipartimento per lo studio del Territorio e delle sue Risorse, Universita di Genova, Corso Europa 26, 16132 Genoa, Italy Quantitative information about spatial patterns in subtidal hard substrate assemblages is scant. Such information is necessary to understand the responses to anthropogenic disturbances in these habitats. Along the coast of Apulia Southern Italy , the collection of the European date mussel Lithophaga lithophagais a strong source of disturbance harvesting is carried out by demolition of the rocky substrate and causes epibiota disappearance. A hierarchical sampling design was used to quantify the spatial variability of subtidal epibenthic assemblages and the extent of rock damage due to L. lithophagaharvesting along 360 km of rocky coasts in Apulia. The surveyed coast was divided into 8 adjacent sectors, and replicate samples were taken by visual inspection at each of the 3 sites nested in each sector. Multivariate analyses indicated that assemblages differed consistently with spatial scale, variability being higher at the largest scale. However, variability among sites within each sector was also detected. Patchiness i.e., average similarity among quadrats was consistent among sectors. Some species were identified as important in characterising and/or differentiating sectors. The pattern of distribution of these species as well as total cover and number of species were analysed by analysis of variance. Results recorded a considerable source of variation at site level. Damage by L. lithophagafishing was shown to be extremely widespread. A humped relationship between patchiness and disturbances by L. lithophagafisheries was obtained. In particular, patchiness at a small scale was highest at intermediate levels of damage, because disturbance produces patches of different size and/or age, leading to mosaic landscapes of epibenthic assemblages. 212 Published version Articolo in rivista Inter Research 0171 8630 Marine ecology. Progress series Halstenbek Marine ecology. Progress series Halstenbek Mar. ecol., Prog. ser. Halstenbek Marine ecology. Halstenbek Marine ecology. Progress series Print Halstenbek MEPS Halstenbek giovanni.fanelli FANELLI GIOVANNI |
