Seasonal variation in the free-running period in two Talitrus saltator populations from Italian beaches differing in morphodynamics and human disturbance

Nardi, M.; Morgan, Elfed; Scapini, Felicita

doi:10.1016/s0272-7714(03)00034-9

Cited by 65 publications

(33 citation statements)

References 24 publications

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“…Other highly significant factors on orientation were those involved in the use of the sun compass (sun azimuth, solar time, sky cloudiness) that played its role mainly when the landscape was not visible, and the time (month) of the experiments. This result highlights a close relation between the amphipods' behaviour and the immediate climatic conditions (Nardi et al, 2003;Scapini et al, 2005), and is confirmed by the significance of air humidity and temperature and the tidal phase. The site was not included in the model, which actually is not surprising, as behaviour represents the immediate response of animals to changes in their life-environment.…”

Section: Discussionsupporting

confidence: 71%

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

Nourisson

Bessa

Scapini

et al. 2014

Ecological Indicators

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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.

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Section: Discussionsupporting

confidence: 71%

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

Nourisson

Bessa

Scapini

et al. 2014

Ecological Indicators

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“…Lower mortality rates on reflective beaches were explained by coastline stability; intrusion of wave-dominated tides is mitigated by the steep face slope on the lower shore, making incoming waves and backwash collide (Gómez & Defeo 1999). This should imply habitat-driven shifts in sandhopper abundance and behaviour according to beach morphodynamics; substantial variations in sandhopper orientation (Scapini et al 1995) and in the circadian rhythm of locomotor activity (Nardi et al 2003) were found as a function of coast stability and dynamics.…”

Section: Discussionmentioning

confidence: 98%

Morphodynamics and habitat safety in sandy beaches: life-history adaptations in a supralittoral amphipod

Defeo

Gómez²

2005

Mar. Ecol. Prog. Ser.

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Understanding the relationships between beach morphodynamics and descriptors of macrofauna assemblages has been a major step in theoretical development in sandy beach ecology. However, the role of morphodynamics in shaping life-history traits is still uncertain. Here, we test the predictions of the habitat harshness hypothesis (HHH) on the life-history traits of the sandhopper Atlantorchestoidea brasiliensis, based on information compiled from 7 Uruguayan sandy beaches spanning a continuum from reflective to dissipative states, over a period of almost 2 yr. A. brasiliensis showed clear population responses to physical variables in a trend opposite to that predicted by the HHH, including an increase in abundance (total, ovigerous females and juveniles) and individual sizes from dissipative to reflective beaches. A generalized additive model explained 46.1% of the deviance in sandhopper abundance and retained all 4 physical descriptors in the model as significant. Sandhopper abundance increased with grain size and beach face slope, and decreased with low values of water content and compaction of the sand. Per capita rate of recruitment increased linearly with adult abundance, i.e. there was a positive density-dependent effect of adults on recruitment rates, which exponentially decreased from reflective to dissipative beaches. Only the proportion of ovigerous females increased towards the dissipative domain. We conclude that the HHH did not accurately predict spatio-temporal fluctuations in population features of A. brasiliensis, particularly because of a limited appreciation of the role played by life-history strategies in explaining population responses to the environment. Our results have important implications for sandy beach macrofauna, particularly supralittoral organisms, and suggest a novel hypothesis (termed here the 'hypothesis of habitat safety'), which states that the combination of narrow swashes and steep slopes makes reflective beaches a more stable and safer environment for supralittoral species.

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“…In the case of the genus Phoxocephalopsis, there is no other evidence regarding the vulnerability of these organisms in the face of human impacts; however, several authors have considered other species of amphipods such as Atlantorchestoidea brasiliensis and Talitrus saltator as bioindicators of anthropogenic and/or tourist activity (WESLAWSKI et al, 2000;NARDI et al, 2003;FANINI et al, 2005;VELOSO et al, 2006;UGOLINI et al, 2008;VELOSO et al, 2008VELOSO et al, , 2009. A. brasiliensis has several interesting features for an indicator species: direct development, distribution in intermediate and upper beach zones, surface burrowing in the sediment, easy visual identification and short life cycle (CARDOSO; .…”

Section: Discussionmentioning

confidence: 99%

Human impact on the benthic macrofauna of two beach environments with different morphodynamic characteristics in southern Brazil

et al. 2012

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A B S T R A C TPollution, exploitation of resources, erosion and recreational activities produce the most common impacts that somehow alter the natural balance of beach ecosystems. The aim of this study was to compare the richness and abundance of the benthic macrofauna of two sectors, one non-urbanized and the other urbanized, on each of two morphodynamically different beaches. Sectors of each beach were analyzed taking into account morphodynamic, anthropogenic (recreational activities) and ecological aspects. Morphodynamically, one of the beaches presented sediment formed of fine sand with a gentle slope and morphodynamism with dissipative characteristics. The other was of sediment formed of medium sand with a steep profile and of intermediate to reflective morphodynamic characteristics. On both beaches during the summer, the urbanized sector was frequented by a greater number of users than the non-urbanized sector. On the beach with dissipative morphodynamism, negative relationships were observed between user abundance and the species Bledius bonariensis, Donax hanleyanus, Thoracophelia furcifera, Excirolana armata, Phoxocephalopsis sp. and Tholozodium rhombofrontalis. On the beach with intermediate to reflective morphodynamics, low abundances of Atlantorchestoidea brasiliensis and Excirolana braziliensis were recorded in the urbanized sector. Thus the results of this study suggest the use of certain species as indicators of human impacts on beach ecosystems. R E S U M OPoluição, exploração de recursos, erosão e atividades recreativas são os impactos mais comuns que de alguma forma alteram o equilíbrio natural do ecossistema praial. O objetivo deste trabalho foi comparar a riqueza e a abundância da macrofauna bentônica entre um setor não urbanizado e outro urbanizado de duas praias morfodinamicamente distintas. Os setores de cada praia foram analisados levando em consideração aspectos morfodinâmicos, antrópicos (atividades recreativas) e ecológicos. Morfodinamicamente, uma das praias apresentou sedimentos formados por areia fina, suave inclinação e morfodinamismo com características dissipativas. A outra praia apresentou sedimentos formados por areia média, perfil íngreme e características morfodinâmicas entre intermediárias a refletivas. Em ambas as praias, durante o verão, o setor urbanizado apresentou maior abundância de usuários do que o setor não urbanizado. Na praia com morfodinamismo dissipativo, relações negativas foram observadas entre a abundância de usuários e a dos organismos Bledius bonariensis, Donax hanleyanus, Thoracophelia furcifera, Excirolana armata, Phoxocephalopsis sp. e Tholozodium rhombofrontalis. Já na praia com morfodinamismo intermediário a refletivo, foram registradas baixas abundâncias de Atlantorchestoidea brasiliensis e Excirolana braziliensis no setor urbanizado. Assim, os resultados do presente estudo sugerem a utilização de algumas espécies como indicadores de impactos antrópicos nos ecossistemas praiais.

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Seasonal variation in the free-running period in two Talitrus saltator populations from Italian beaches differing in morphodynamics and human disturbance

Cited by 65 publications

References 24 publications

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

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

Morphodynamics and habitat safety in sandy beaches: life-history adaptations in a supralittoral amphipod

Human impact on the benthic macrofauna of two beach environments with different morphodynamic characteristics in southern Brazil

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