Marine ecosystems are subject to global and local impacts, both contributing to dramatic changes in coastal communities. Assessing such changes requires time series or the revisitation of sites first surveyed in the past. In both cases, data are not necessarily collected by the same observers, which could lead to a bias in the results. In the Marine Protected Area (MPA) of Capo Carbonara (Sardinia, Italy), established in 1998, rocky reef communities were first assessed in 2000 by two diving scientists. Twenty years later, the same rocky reefs were resurveyed using the same method by two other diving scientists. In both surveys, semi-quantitative data on conspicuous species were collected at five sites in four depth zones, providing the possibility of assessing change over time. To explore the influence of climate and local pressures, existing data on sea surface temperature, resident population, tourism and diving activities were analysed. The reef communities of the Capo Carbonara MPA have distinctly changed over time, mostly under the effect of seawater warming, as highlighted by the occurrence of thermophilic species and by other climate-related indicators. On the other side, species vulnerable to local human pressures have increased over time, demonstrating the effectiveness of the protection measures undertaken by the MPA. Comparing data collected by four different observers in the two periods demonstrated that change over time was significantly greater than variability between the observers.

Variability between observers does not hamper detecting change over time in a temperate reef

Azzola A.;Bianchi C. N.;Morri C.;Oprandi A.;Montefalcone M.
2022

Abstract

Marine ecosystems are subject to global and local impacts, both contributing to dramatic changes in coastal communities. Assessing such changes requires time series or the revisitation of sites first surveyed in the past. In both cases, data are not necessarily collected by the same observers, which could lead to a bias in the results. In the Marine Protected Area (MPA) of Capo Carbonara (Sardinia, Italy), established in 1998, rocky reef communities were first assessed in 2000 by two diving scientists. Twenty years later, the same rocky reefs were resurveyed using the same method by two other diving scientists. In both surveys, semi-quantitative data on conspicuous species were collected at five sites in four depth zones, providing the possibility of assessing change over time. To explore the influence of climate and local pressures, existing data on sea surface temperature, resident population, tourism and diving activities were analysed. The reef communities of the Capo Carbonara MPA have distinctly changed over time, mostly under the effect of seawater warming, as highlighted by the occurrence of thermophilic species and by other climate-related indicators. On the other side, species vulnerable to local human pressures have increased over time, demonstrating the effectiveness of the protection measures undertaken by the MPA. Comparing data collected by four different observers in the two periods demonstrated that change over time was significantly greater than variability between the observers.
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11567/1085700
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? 0
  • Scopus 0
  • ???jsp.display-item.citation.isi??? 0
social impact