Spatiotemporal Assessment of Littoral Waterbirds for Establishing Ecological Indicators of Mediterranean Coastal Lagoons

Pablo Farinós-Celdrán,Francisco Robledano-Aymerich,María Francisca Carreño,Javier Martínez-López

doi:10.3390/ijgi6080256

Abstract

Waterbirds are vital indicators of anthropogenic influence on the ecological status of Mediterranean coastal lagoons. Our study relates temporal waterbird data to key environmental gradients at catchment scale that have a structural or functional influence on littoral waterbird assemblages at different scales. During two full-year cycles and two additional wintering seasons, the nearshore waterbird assemblages of the Mar Menor coastal lagoon (Murcia Region, SE Spain) were monitored monthly. Several biological indicator variables were related to the anthropogenic environmental gradient in the catchment area. Results showed that there was a strong dependence of waterbird assemblages on the distance to shore, emphasizing the importance of the first 100-m band, in which many species relevant to conservation converge on food resources. Well-preserved shoreline tracts therefore had a clear positive effect on community richness and diversity values, and were correlated with the occurrence of some species. These results clearly support the need for effective protection and restoration measures of such littoral habitats. Specific responses to local disturbing processes were nested within habitat and landscape preferences, supporting the value of aquatic birds as integrative ecological signals in semi-enclosed coastal systems. Moreover, waterbird-based indicators responded positively to environmental improvements both qualitatively and quantitatively.

Highlights

The need to understand how wildlife responds to the broad-ranging impacts of development is becoming increasingly important as human populations continue to grow and urbanization spreads around the globe [1]
In winter Total Bird Use (TBU) did not differ significantly between B1 and B4, but with respect to B2 and B3, while in summer it behaved like other indices (B1 differs from the remaining bands)
Our study showed that in such semi-enclosed coastal lagoon systems, the richness and abundance of waterbirds can be favored under moderate degradation states, but usually only in the presence of well-preserved natural environments (NDS, NCS) that act as buffers for pollution in the long term

Summary

Introduction

The need to understand how wildlife responds to the broad-ranging impacts of development is becoming increasingly important as human populations continue to grow and urbanization spreads around the globe [1]. Integrated, quantitative expressions of anthropogenic stress over large geographic areas (e.g., watersheds and their associated aquatic ecosystems) can be valuable tools in environmental research and management, and a basis for the study of the response of key indicator taxa to anthropogenic pressure [2,3]. The identification of potential indicator species, their monitoring, and the ecological quantification of their responses have been proven to be useful tools in environmental management [4]. In this regard, relating ecological status to anthropogenic landscape processes helps in the development of cost-effective environmental indicators and in the implementation of remedial action [5]. Coastal lagoons (CLs), as semi-enclosed coastal systems, and Mediterranean lagoons in particular, are especially threatened by human stressors given the high occurrence of intensive activities associated with a dense human population around them [8,9]

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