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Benthic macrofauna as an indicator of Ecological Integrity at an ocean beach with touristic purpose; Playa El Rivero, Punta Del Diablo, Rocha, Uruguay

2020; Elsevier BV; Volume: 39; Linguagem: Inglês

10.1016/j.rsma.2020.101441

2352-4855

Pablo Limóngi, Alvar Carranza,

Marine Bivalve and Aquaculture Studies

The concept of Ecological Integrity (EI) refers to the capacity of a place to sustain and maintain the biota in such conditions that allows it to function as a balanced, integrated and adaptive system, and can be derived by comparing present vs. past or spatial reference baseline conditions. Here we assess the EI of Playa El Rivero (34°2'29.35"S, 53∘32'21.14"W) in Punta Del Diablo resort, Uruguay. This 600 m-length, previously unstudied sandy beach is one of the main attractions of the resort, receiving thousands of tourists during summer. Accordingly, conspicuous human impacts are concentrated in the more dissipative end of the beach. In order to derive EI values, a large number of indicators (n=20), including population and community level univariate descriptors for benthic macrofauna, as well as direct indicators of EI (AMBI, M-AMBI and Buckland indices) were assessed and integrated. The distribution of population and community level variables were compared across the along-shore axis with the expected distribution under the Swash Exclusion Hypothesis (SHE) and the Habitat Harshness Hypothesis (HHH), which predict a decrease in richness, biomass and abundance from reflective to dissipative conditions. To derive a global value, an EI value was calculated for population and community levels as well as according to direct impact indicators. EI thus ranged from 1 (no measurable or significant impacts) to 0 (completely dysfunctional system). Integrating all types of indicators, a value of 0.76 was obtained for the beach under study. This value integrates both chronic and putative "press" disturbance occurring during the high tourist season in the period under study and suggests a sub-optimal state (ca. 20% reduction) of the health of the system studied, probably related to the sum of chronic anthropogenic impacts that the beach arc presents. This value is considered as an objective (but probably conservative) reference point in order to evaluate the effectiveness of future management measures.