Habitat loss and gain: Influence on habitat attractiveness for estuarine fish communities. (15th October 2017)

• Record Type: Journal Article
• Authors: Amorim, Eva; Ramos, Sandra; Elliott, Michael; Franco, Anita; Bordalo, Adriano A.
• Is Part Of: Estuarine, coastal and shelf science. Volume 197(2017)
• Page Start: 244
• Page End: 257
• Publication Date: 2017-10-15
• Subjects: Estuaries -- Habitat changes -- Fish habitat attractiveness -- Physiotopes; Estuarine oceanography -- Periodicals; Coasts -- Periodicals; Estuarine biology -- Periodicals; Seashore biology -- Periodicals; Coasts; Estuarine biology; Estuarine oceanography; Seashore biology; Periodicals; 551.461805
• DOI: 10.1016/j.ecss.2017.08.043
• Languages: English
• ISSNs: 0272-7714

Abstract

Abstract: Habitat structure and complexity influence the structuring and functioning of fish communities. Habitat changes are one of the main pressures affecting estuarine systems worldwide, yet the degree and rate of change and its impact on fish communities is still poorly understood. In order to quantify historical modifications in habitat structure, an ecohydrological classification system using physiotopes, i.e. units with homogenous abiotic characteristics, was developed for the lower Lima estuary (NW Portugal). Field data, aerial imagery, historical maps and interpolation methods were used to map input variables, including bathymetry, substratum (hard/soft), sediment composition, hydrodynamics (current velocity) and vegetation coverage. Physiotopes were then mapped for the years of 1933 and 2013 and the areas lost and gained over the 80 years were quantified. The implications of changes for the benthic and demersal fish communities using the lower estuary were estimated using the attractiveness to those communities of each physiotope, while considering the main estuarine habitat functions for fish, namely spawning, nursery, feeding and refuge areas and migratory routes. The lower estuary was highly affected due to urbanisation and development and, following a port/harbour expansion, its boundary moved seaward causing an increase in total area. Modifications led to the loss of most of its sandy and saltmarsh intertidal physiotopes, which were replaced by deeper subtidal physiotopes. The most attractive physiotopes for fish (defined as the way in which they supported the fish ecological features) decreased in area while less attractive ones increased, producing an overall lower attractiveness of the studied area in 2013 compared to 1933. The implications of habitat alterations for the fish using the estuary include potential changes in the nursery carrying capacity and the functioning of the fish community. The study also highlighted the poor knowledge of the impacts of habitat changes on fish due to coastal development and urbanisation and emphasises that ecosystem management and conservation will benefit from a wider understanding of habitat functional roles and habitat changes influencing the functioning and structure of the fish communities. Graphical abstract: Highlights: Investigation of the habitat loss and gain of an estuarine area over 80 years. An ecohydrological classification system was used to quantify changes. The lower estuary was highly affected due to urbanisation and development. The most attractive physiotopes for fish decreased in area. Overall lower attractiveness of the studied area for fish in 2013 compared to 1933.