Rapid Biodiversity Assessment and Monitoring Method for Highly Diverse Benthic Communities: A Case Study of Mediterranean Coralligenous Outcrops

Abstract

Increasing anthropogenic pressures urge enhanced knowledge and understanding of the current state of marine biodiversity. This baseline information is pivotal to explore present trends, detect future modifications and propose adequate management actions for marine ecosystems. Coralligenous outcrops are a highly diverse and structurally complex deep-water habitat faced with major threats in the Mediterranean Sea. Despite its ecological, aesthetic and economic value, coralligenous biodiversity patterns are still poorly understood. There is currently no single sampling method that has been demonstrated to be sufficiently representative to ensure adequate community assessment and monitoring in this habitat. Therefore, we propose a rapid non-destructive protocol for biodiversity assessment and monitoring of coralligenous outcrops providing good estimates of its structure and species composition, based on photographic sampling and the determination of presence/absence of macrobenthic species. We used an extensive photographic survey, covering several spatial scales (100s of m to 100s of km) within the NW Mediterranean and including 2 different coralligenous assemblages: Paramuricea clavata (PCA) and Corallium rubrum assemblage (CRA). This approach allowed us to determine the minimal sampling area for each assemblage (5000 cm2 for PCA and 2500 cm2 for CRA). In addition, we conclude that 3 replicates provide an optimal sampling effort in order to maximize the species number and to assess the main biodiversity patterns of studied assemblages in variability studies requiring replicates. We contend that the proposed sampling approach provides a valuable tool for management and conservation planning, monitoring and research programs focused on coralligenous outcrops, potentially also applicable in other benthic ecosystems.

Coralligenous and maërl habitats: predictive modelling to identify their spatial distributions across the Mediterranean Sea

“…Therefore, coralligenous outcrops and maërl beds are two complex habitats featured by a suite of different species, which will vary locally and regionally 51,52 . The coralligenous habitat can even be considered to be a submarine seascape, or community mosaic, rather than a single community 17 .…”

Effectiveness of different investigation procedures in detecting anthropogenic impacts on coralligenous assemblages

“…Coralligenous assemblages have been widely studied in relation to species composition (Laubier 1966, Hong 1982, Garrabou et al 2002, Casellato and Stefanon 2008, patterns of spatial and temporal variability (Ferdeghini et al 2000, Cocito et al 2002, Piazzi et al 2004, Balata et al 2005, 2006a, 2006b, Virgilio et al 2006, Ponti et al 2011, and responses to anthropogenic impacts (Hong 1983, Garrabou et al 1998, Balata et al 2007a, 2007b, Piazzi et al 2007, Roghi et al 2010. Recently, several methods have been developed to assess ecological quality of coralligenous assemblages through a non-destructive approach (Kipson et al 2011, Deter et al 2012a, Gatti et al 2012. In this context, a minimal area was defined for photographic samples (Kipson et al 2011, Teixido et al 2013).…”

“…Recently, several methods have been developed to assess ecological quality of coralligenous assemblages through a non-destructive approach (Kipson et al 2011, Deter et al 2012a, Gatti et al 2012. In this context, a minimal area was defined for photographic samples (Kipson et al 2011, Teixido et al 2013). However, several aspects necessary to assess the suitability of the sampling methods, such as the comparison between destructive and non-destructive approaches or the spatial scales to be examined, were not evaluated.…”

Integración de el índice ESCA por medio de los macro-invertebrados sésiles

“…Thus, combining macroalgae and macro-invertebrates into the ESCA-TA index may increase the efficiency of the index in determining the ecological quality of marine coastal areas, as the response spectrum of the index to human pressures can be extended by the use of a higher number of descriptors. Moreover, the use of the ESCA-TA index may allow a finer intercalibration with other monitoring methods that consider the whole coralligenous assemblages (Kipson et al 2011, Deter et al 2012, Gatti et al 2015a, and therefore meet the requirements of the European directives.…”

“…Conversely, little is known about the response of sessile coralligenous macroinvertebrates to stress, even if some taxa are recognized to be sensitive to human-induced alterations (Bavestrello et al 1997, Garrabou et al 1998, Gatti et al 2015b). The concurrent use of both macroalgae and sessile macro-invertebrates allows a wider spectrum of human-induced alterations to be detected than when a single component is used, thus better evaluating the ecological quality of coralligenous assemblages (Kipson et al 2011, Sartoretto et al 2014, Gatti et al 2012.…”