Medium- and Long-term Recovery of Estuarine and Coastal Ecosystems: Patterns, Rates and Restoration Effectiveness

Abstract

Many estuarine and coastal marine ecosystems have increasingly experienced degradation caused by multiple stressors. Anthropogenic pressures alter natural ecosystems and the ecosystems are not considered to have recovered unless secondary succession has returned the ecosystem to the pre-existing condition or state. However, depending upon the scales of time, space and intensity of anthropogenic disturbance, return along the historic trajectory of the ecosystem may: (1) follow natural restoration though secondary succession; (2) be re-directed through ecological restoration, or (3) be unattainable. In order to address the gaps in knowledge about restoration and recovery of estuarine and coastal ecosystems, this special feature includes the present overview and other contributions to provide a synthesis of our knowledge about recovery patterns, rates and restoration effectiveness. From the 51 examples collated in this contribution, we refine the recovery from the list of stressors into six recovery mechanisms: (1) recovery from sediment modification, which includes all aspects of dredging and disposal; (2) recovery by complete removal of stressors limiting natural ecosystem processes, which includes tidal marsh and inundation restoration; (3) recovery by speed of organic degradation, which includes oil discharge, fish farm wastes, sewage disposal, and paper mill waste; (4) recovery from persistent pollutants, which includes chemical discharges, such as TBT; (5) recovery from excessive biological removal, related to fisheries and (6) recovery from hydrological and morphological modification. Drawing upon experience both from these many examples and from an example of one comprehensive study, we show that although in some cases recovery can take <5 years, especially for the short-lived and high-turnover biological components, full recovery of coastal marine and estuarine ecosystems from over a century of degradation can take a minimum of 15-25 years for attainment of the original biotic composition and diversity may lag far beyond that period.

Influence of piers on functional groups of benthic primary producers and consumers in the channel of a subtropical coastal lagoon

“…All individuals were examined under the microscope, identified and counted. Subsequently, the organisms were classed as either living in or on the sediment, and their displacement potential (Table 2): motile epifauna, discretely motile epifauna, motile infauna and discretely motile infauna, was recorded (FAUCHALD; JUMARS, 1979;BREMNER et al, 2006). To check on whether piers could change sedimentation patterns we took three sediment samples of 200 cm 3 , 5 cm deep.…”

“…Regarding the macrofauna, artificial habitats may alter dominant feeding strategies (WEISSBERGER et al, 2008), morphotype (PAGLIOSA, 2005) and motility (BREMNER et al, 2006;GAMITO;FURTADO;) of soft sediments consumer-trophic level assemblages. In fact, the way to search for (motility), identify and take (morphology) food resources from the environment are so coupled that any other possible functional characteristics tend to be a secondary reflection of this interaction (FAUCHALD;JUMARS, 1979).…”

“…The macroalgal and macrofaunal benthic assemblages have been used historically as indicators of environmental quality, making them valuable tools for assessing potential changes within marine ecosystems (BORJA et al, 2010). Here, we used these two trophically distinct functional groups to assess the pressure from increased urbanization in coastal areas, specifically regarding piers structures.…”

Integrated coastal zone management in Italy: a gap between science and policy

“…In the following years, this kind of holistic approach to coastal system became the key issue for a sustainable development of coastal areas (Billè 2008). So, European Policy on Mediterranean Sea has been directed towards the protection of the ecological status of coastal systems (Ricketts and Harrison 2007;Barnes and McFadden 2008;Borja et al 2010). In this framework the Protocol on ICZM, signed by Mediterranean countries in 2008, is the first legal instrument on this subject (Barale and Özhan 2010).…”

Influence of oceanographic seasonality and dredging activities on the fish larvae assemblage in the Port of Aratu, Todos os Santos Bay

“…However, despite its economic importance, dredging introduces potential impacts to the environment and is currently one of the main problems in coastal management (Borja et al, 2010).…”