Macrofaunal community abundance and diversity and talitrid orientation as potential indicators of ecological long-term effects of a sand-dune recovery intervention

Abstract

a b s t r a c tIn the last decades the increasing urban development on coastal areas have produced extensive modifications on shores all over the world, making critical the active management of pressures on sandy beaches. The use of engineering solutions to counteract beach erosion has been significantly increasing; the ecological indicators used to monitor these interventions generally focus on short-and medium-term effects, while little is known on their effectiveness on long-term temporal scales. The following ecological indicators have been tested in the present study: (a) macrofaunal community abundance and diversity and (b) orientation behaviour of Talitrus saltator, a talitrid amphipod widespread on Mediterranean and European Atlantic sandy beaches. Two sites were considered on a sandy beach of the Portuguese Atlantic coast, one located in front of a natural dune and the other at about 500 m of distance, where the dune had been rebuilt between 2000 and 2008 using geotextile tubes. In 2011 and 2012, macrofauna sampling and orientation experiments on T. saltator were performed at both sites in spring and autumn; contemporaneously the main environmental variables were registered. Macrofaunal data were analysed through multivariate statistical tests, and for the orientation distributions the circular statistics were calculated and multivariate analyses for angular data were performed. Geotextiles appeared to be successful in stabilising the recovered dunes; accordingly, the diversity of the macrofaunal communities and the orientation performances of T. saltator showed no differences between the altered and control sites. Significant reductions were nevertheless observed in the artificial-dune site regarding the abundance of T. saltator and, to a lesser extent, macrofaunal densities, likely ascribable to the presence of geotextiles instead of a vegetated natural dune, preventing invertebrates to burrow into the sand. These results, complementing a more comprehensive study on these two sites, indicate the abundance of T. saltator as the best indicator to follow long-term effects of this kind of soft-engineering intervention. The use of this bioindicator may be recommended for the late phases of monitoring procedures in dune-recovery processes.

An ecological indicator to evaluate the effect of chemical insecticide pollution management on complex ecosystems

“…In this study we adopted the constructive strategies of optimizing insecticide variety structure (the use of eight insecticides with slight toxicity was rotated, and elimination of the two insecticides with moderate toxicity, 48% chlorpyrifos EC and 2.5% deltamethrin), installing lamps and installing trap devices to control insect pests in scallion fields, which have effectively reduced the use of chemical insecticides and ensure the yields and quality of scallions. However, the ecological indicator for chemical insecticide pollution management in scallion fields has scarcely been explored although the ecological indicators for urban ecosystem management (Chen and Wang, 2014), sanddune recovery intervention (Nourisson et al, 2014), wastewater treatment (Shao et al, 2014), ecological footprint (Al-mulali et al, 2015) have been studied.…”

Talitrid orientation as bioindicator of shoreline stability: Protected headland-bays versus exposed extended beaches

“…Arthropod community features and orientation of talitrids to the shoreline had been used in similar contexts to monitor the stability of the beach ecosystem with respect to changed sedimentary dynamics caused by soft and hard engineering measures to stabilise beaches against erosion (Fanini et al, 2007;Bessa et al, 2013;Nourisson et al, 2014). Measurable changes in talitrid orientation parameters, such as the precision with respect to the shoreline direction, would provide a tool for a monitoring programme of the impact of man-made structures on the beach ecosystem (Scapini, 2014).…”

“…The link between the behavioural adaptation of local populations strictly inhabiting sandy beaches, such as talitrids, and shoreline stability provided by natural and/or artificial headlands represent useful information for integrate (biotic and sedimentary) monitoring of coastal processes, and for the interpretation of species adaptation to changing environments. Other studies have proposed etho-assays (orientation tests) as indicators of environmental impacts, to monitor artificial coastline stabilisation both in the short-and medium-term (Fanini et al, 2007;Bessa et al, 2013;Nourisson et al, 2014) or as biomarker of metal pollution (Ungherese and Ugolini, 2009). The interest in using animal behaviour as ecological adaptation lies in the fact that behaviour integrates several driving forces at the level of individuals (that express the behaviour) and populations.…”

Habitat Preference and Effects of Coastal Fragmentation in the Sand-Dwelling Spider <i>Allocosa brasiliensis</i> (Lycosidae, Allocosinae)

“…Habitat fragmentation negatively affects species communities in ecosystems, leading to the reduction of its natural areas, the isolation of their populations, increasing of edge effect, and consequently, causing a trend towards species extinction [7]. Nowadays, a quarter of the world's population lives in coastal areas [5] [8]. This phenomenon, along with the impacts of changes in land use, results in the alteration of coastal ecosystems in many parts of the planet, causing fragmentation and reduction of the natural environments [5] [9] [10].…”

“…Nowadays, a quarter of the world's population lives in coastal areas [5] [8]. This phenomenon, along with the impacts of changes in land use, results in the alteration of coastal ecosystems in many parts of the planet, causing fragmentation and reduction of the natural environments [5] [9] [10]. Coastal areas generally are characterized by narrow shore parallel bands that comprise species assemblages specially adapted to live in changeable climatic conditions and environmental constraints such as strong winds, sand movements, high evaporation, high salinity, and limited nutrients [11] [12].…”