title: The spread of Caulerpa racemosa var. cylindracea in the Mediterranean Sea: an example of how biological invasions can influence beta diversity.
abstract: The present study aims to evaluate if invasion of Caulerpa racemosa var. cylindracea can affect both alpha and beta diversity in Mediterranean coastal system. The following hypotheses were tested: (i) measures of alpha diversity differ between invaded and non-invaded assemblages (ii) this pattern is consistent between different habitats, (iii) assemblages from habitats which are naturally very different tend to be more similar when invaded compared to non-invaded situations. Results showed that Mediterranean benthic assemblages invaded by C. racemosa var. cylindracea were characterized by lower values of alpha diversity than non-invaded assemblages; moreover, differences between deep (25 m) and shallow water (5m) assemblages appeared lower in invaded than in non-invaded areas, with a decrease of beta diversity. This homogenisation of habitats was related to a lack of several characteristic species and to a higher abundance of few opportunistic species in invaded areas, particularly turf-forming algae. Moreover, variability in taxa composition was lower in invaded than in non-invaded assemblages in both habitats.
authors: Dipartimento di Biologia, Università di Pisa, Via A. Volta 6, 56126 Pisa, Italy.
authors: Luigi
authors: L
authors: Piazzi
authors: David
authors: D
authors: Balata
mesh_terms: D000818:Animals; D044822:Biodiversity; D046068:Caulerpa / Q000502:physiology*; D017753:Ecosystem; D004784:Environmental Monitoring; D056890:Eukaryota / Q000502:physiology; D007448:Invertebrates / Q000502:physiology; D008522:Mediterranean Sea; D011157:Population Dynamics