Is faunal diversity on Maltese sandy beaches related to intensity of human use?

Sandy beaches are rare in the Maltese Islands where only some 2.4% of the ca 271km coastline is sedimentary; yet such beaches are much sought after for their amenity value by tourists and locals alike. Carrying capacity studies conducted by the Malta tourism authorities have shown that most beaches are under very heavy use while a study by Deidun et al. (2003) has indicated that the fauna of Maltese sandy beaches tends to be impoverished compared to other Mediterranean beaches and has hinted that this may be a result of lack of recruitment due to the relative isolation of these beaches. Therefore human use of Maltese sandy beaches may potentially be a key factor affecting faunal diversity of these beaches. We explored this hypothesis by sampling the faunal assemblages of four Maltese beaches (Gnejna and White Tower Bay on Malta, and Xatt l-Ahmar and Ramla l-Hamra on Gozo) using pitfall traps set up in the wet and dry zones of each beach during the summer, when human use is expected to be highest. Human use of these beaches was assessed by estimating human occupancy of the beaches from standardised photographs. Beach occupancy values of 2400, 5700, 6700, and 12300 persons per square km were estimated for Ramla, White Tower Bay, Xatt l-Ahmar and Gnejna, respectively, establishing a gradient of anthropogenic impact with Gnejna as the most impacted beach and Ramla the least. Three components of faunal diversity were considered: population size (number of individuals), species richness, and taxonomic composition. Faunal population size ranged from 7 individuals/trap/hour for Xatt l-Ahmar to 199 individuals/trap/hour for Ramla in the wet zone, and from 22 individuals/trap/hour for White Tower Bay to 87.33 individuals/trap/hour for Gnejna in the dry zone. The species richness ranged from 7 species (Xatt l-Ahmar) to 17 species (White Tower Bay). Between them, Amphipoda, Isopoda, Coleoptera Dermaptera and Hymenoptera accounted for the bulk of both species and individuals collected. There were no statistically significant correlations between population size, species richness and taxonomic composition. The species collected from the four beaches was categorized into psammophiles, coastal species (occurring in coastal habitats but not restricted to sandy beaches) and euryoecious (ubiquitous) species. Ramla exhibited the highest proportion of psammophiles (98.4% of all species collected at Ramla) and the lowest proportion of ubiquitous ones (1.5% of all species), whilst for Xatt L-Ahmar the equivalent figures were 31.8% and 61.8% for ubiquitous and psammophilic species respectively From the present study it results that there is no trend between any of the three components of faunal diversity analysed and the degree of human occupancy of the beaches, and the only tangible human impact was related to faunal habitat–use specificity. This suggests that human use of the beaches has no direct impact on the faunal assemblages of the mediolittoral and supralittoral zone of the beaches studied but that high levels of human disturbance result in generalists displacing specialist psammophilic species. In spite of these results, intense human use of Maltese sandy beaches is of conservation concern since previous work has indicated a high degree of ‘compartmentalisation’ with different beaches harbouring distinct faunal assemblages either due to natural inter-beach barriers to dispersal, or due to unique environmental conditions present on the different beaches, including the nature and intensity of anthropogenic pressures. In addition, the present study addresses only the direct effect of trampling by beach visitors; indirect negative impacts, such as those of beach cleaning, have been well documented in other studies.peer-reviewe

Preserve or retreat? Willingness-to-pay for Coastline Protection in New South Wales

Coastal erosion is a global and pervasive phenomenon that predicates a need for a strategic approach to the future management of coastal values and assets (both built and natural), should we invest in protective structures like seawalls that aim to preserve specific coastal features, or allow natural coastline retreat to preserve sandy beaches and other coastal ecosystems. Determining the most suitable management approach in a specific context requires a better understanding of the full suite of economic values the populations holds for coastal assets, including non-market values. In this study, we characterise New South Wales residents willingness to pay to maintain sandy beaches (width and length). We use an innovative application of a Latent Class Binary Logit model to deal with Yea-sayers and Nay-sayers, as well as revealing the latent heterogeneity among sample members. We find that 65% of the population would be willing to pay some amount of levy, dependent on the policy setting. In most cases, there is no effect of degree of beach deterioration characterised as loss of width and length of sandy beaches of between 5% and 100% on respondents willingness to pay for a management levy. This suggests that respondents who agreed to pay a management levy were motivated to preserve sandy beaches in their current state irrespective of the severity of sand loss likely to occur as a result of coastal erosion. Willingness to pay also varies according to beach type (amongst Iconic, Main, Bay and Surf beaches) a finding that can assist with spatial prioritisation of coastal management. Not recognizing the presence of nay-sayers in the data or recognizing them but eliminating them from the estimation will result in biased WTP results and, consequently, biased policy propositions by coastal managers.Comment: arXiv admin note: substantial text overlap with arXiv:1902.0241

Low faunal diversity on Maltese sandy beaches : fact or artefact?

Eight sandy beaches on Malta and two on Gozo were sampled for macrofauna to test the hypothesis that Maltese beaches have an intrinsically low diversity. Stations distributed in the supralittoral (dry zone), mediolittoral (wet zone) and upper infralittoral (submerged zone to 1m water depth) were sampled by sieving core samples and standardised searching during daytime, and pitfall trapping and standardised sweeping of the water column using a hand-net at night, as appropriate. Physical parameters of the sediment were measured and human occupancy of the beaches was estimated. From the supralittoral and mediolittoral, 39 species represented by 1584 individuals were collected by the combined techniques of pitfall trapping, sieving and standard searching. For Ramla beach, which had the highest diversity, 267 individuals representing 25 infaunal species were collected by sieving from a combined volume of 1.175m3 of sand, and 149 individuals representing 28 epifaunal species were collected by standardised searching from a combined area of 700m2 of sand during two winter and two summer sampling sessions between 1992 and 1993. For nine other beaches sampled during the summer of 2000, only six macrofaunal species were collected from core samples, with overall population densities ranging from 4.13 to 45.45 individualsm 2. Only 92 individuals belonging to 12 species were collected by hand-net from the uppermost infralittoral of five beaches sampled using this method during the summer of 2000. Taxa of gastropods, bivalves, decapods, mysids and staphylinid beetles generally abundant on Mediterranean sandy beaches, were entirely absent from the beaches sampled. Few correlations that could explain the impoverishment of Maltese sandy beaches were found between physical parameters and faunal abundances, and other factors such as inadequate sampling effort, human disturbance and marine pollution were also excluded; however, seasonally biased sampling may partly explain the results obtained. One factor that may explain why certain species are missing could be lack of recruitment, due to Malta’s geographical isolation from the European and African mainlands. 2003 Elsevier Ltd. All rights reserved.peer-reviewe

Nematode diversity and zonation patterns on sandy beaches

The European coastline consists for more than 30 % of sandy beaches. In spite of their rather barren and desert-like apperance, these European coasts harbour a highly diverse fauna and flora and some of them are even highly productive. On the other hand these beaches are subjected to strong anthropogenic pressure (e.g. pollution, eutrophication, coastal fisheries and tourism), which has substantial impact on the interstitial life and functioning of the sandy beach ecosystem. In contrast to the well-documented tropical sandy beaches, little is known about the structural and functional diversity of the different benthic components. This study aims to get an idea about the structural and functional diversity of meiobenthos (all Metazoans between 1 mm and 38 µm), emphasizing on free-living marine nematodes, of three European sandy beaches (i.e. Belgium, Poland and Italy). Nematodes are very suitable for monitoring and will be used in the second part of this study to compare and evaluate the diversity and productivity between ‘disturbed’ and ‘undisturbed’ sandy beaches. In order to document the structural and functional diversity of the meiobenthos of the above-mentioned European sandy beaches, quantitative samples along transects have been collected on both disturbed and undisturbed parts of the beaches. Meiobenthos was processed and identified by standard procedures and further analysed by means of statistical and multivariate techniques. Only nematodes have been analysed at species level. 12 different meiofaunal and around 150 species of free-living marine nematodes in total have been recognized on these beaches. Nematodes dominated almost all sampling stations. Among the free-living marine nematodes several new species have been found, indicating the very poor knowledge of the European sandy beach nematofauna. The nematode biodiversity was highest on the Belgian beaches (ca 90 species), followed by the Italian beaches (ca 40 species) and Polish beaches (ca 20 species). Nematode zonation patterns have been detected as well

Nematodes from sandy beaches of Guanabara Bay, Rio de Janeiro, Brazil

This work assessed the nematode composition in three sandy beaches located at Guanabara Bay, Rio de Janeiro, Brazil (22°24’ and 22°57’S; 42°33’ and 43°19’W). These microtidal, sheltered sandy beaches (Bica, Bananal and Coqueiros) were surveyed on January and June 2001, during the low tide. Samples were taken using a PVC core of 10cm2. Nematodes were extracted using the sugar-flotation methodology. The sediment of these beaches was mainly composed of sand and showed a variation between medium to very coarse sediments. In total 6312 specimens were identified up to the genus level or when possible to species level. At the three beaches, 62 genera were found, belonging to 25 families and distributed along of 8 orders. Chromadoridae was the most abundant family in terms of genera. All the families found have also been recorded from previously studied beaches. Amongst the genera found, four of them (Deontolaimus, Dracograllus, Phanodermella and Subsphaerolaimus) were for the first time recorded for Brazilian’s coastline. The number of genera occurring on the Guanabara beaches (31 for Bica, 39 for Bananal and 46 for Coqueiros) is more or less similar to another Brazilian sandy beach whereas these values showed higher variation concerning worldwide tropical and non-tropical beaches. The first occurrence of four genera for the Brazilian coastline suggest the possibility to discover new species in this bay, therefore to the need for further development of nematode taxonomy in Brazil

Interactions between nematode biodiversity and anthropogenic disturbances on European sandy beaches (poster)

The European coastline consists for more than 30% of sandy beaches. In spite of their rather barren and arid view, these European coasts harbour a highly diverse fauna and flora and some of them are even highly productive. In contrast to tropical sandy beaches little is known about the structural and functional diversity of the different benthic components. This project firstly aims to get an idea about the structural and functional diversity of meiobenthos (all Metazoans between 1mm and 38µm), emphasizing on free-living marine nematodes, of three European sandy beaches (i.e. Belgium, Poland and Italy).European sandy beaches are under strong anthropogenic pressure (e.g. pollution, eutrofication, coastal fisheries and tourism), which has substantial impact on the interstitial life and functioning of the sandy beach ecosystem. Nematodes are very suitable for monitoring and will be used in the second part of this study to compare diversity and productivity between ‘disturbed’ and ‘undisturbed’ sandy beaches of three European coasts. Finally, indicator species will be identified based on their occurrence in disturbed sediments. Those indicator species could be used in further investigation as a tool for measuring disturbance of sandy sediments and could also be useful in coastal conservation. In order to document the structural and functional diversity of meiobenthos of the above-mentioned European sandy beaches, quantitative samples along transects from the upper to the lower beach are collected at the end of the touristic season. Meiobenthic communities will be followed during a one year cycle by means of monthly sampling campaigns along the same transect between mean high and low water level on both disturbed and undisturbed parts of the beaches. Meiobenthos will be processed and determined by standard procedures and further analysed by means of statistical and multivariate techniques. Only nematodes will be enumerated and analysed at species level. In addition, productivity of nematodes will be calculated.Some field experiments to investigate effect of disturbance on sediment will be set up in order to monitor the recolonization of pristine beaches after different degrees of disturbance

Variabilidad morfométrica en crustáceos de playas arenosas de la Isla Grande de Chiloé, sur de Chile

Indexación: Web of Science; Scielo.The macroinfauna of exposed sandy beaches along the Chilean coast is dominated by crustaceans, which show an across-shore zonation; the talitrid amphipod Orchestoidea tuberculata as the dominant taxon in the upper levels, the cirolanid isopod Excirolana hirsuticauda is dominant in the mid-intertidal, and the anomuran crab Emerita analoga is common in the low levels. This study analyses samples collected during the spring of 2001 and 7 morphological characters were measured on 30 adults of each species: body length, body height, body width, antennae and uropodal exopod lengths. The study sites were located near 42°S, an area where various beach types (i.e., reflective, intermediate and dissipative) occur along the northern coasts of the Chilean archipelagos. The morphometric variability of O. tuberculata, E. hirsuticauda and E. analoga was analyzed using cluster and principal component analysis. The results of this study showed that independently of beach type, individuals of O. tuberculata inhabiting proximal beaches showed greater similarity than individuals inhabiting beaches located distant from each other. Individuals of E. analoga inhabiting similar beach types showed greater similarity than individuals living in different beach types. These results are discussed in relation to across-shore zonation and the natural history of these species.La macroinfauna de playas arenosas expuestas en la costa chilena está dominada por crustáceos, los cuales muestran una zonación transversal; el anfípodo talítrido Orchestoidea tuberculata es el taxón dominante en los niveles superiores, el isópodo cirolánido Excirolana hirsuticauda lo es en la parte media del intermareal y el anomuro Emerita analoga es dominante en los niveles bajos. Este estudio examinó la variabilidad morfométrica de estas 3 especies de crustáceos en relación a los tipos morfodinámicos de playas. Las muestras fueron recolectadas durante la primavera de 2001 y se examinaron 7 caracteres morfológicos medidos en 30 adultos de cada especie: longitud del cuerpo, alto del cuerpo, ancho de cuerpo, longitud de las antenas y longitud de los urópodos. Los sitios de estudio se localizaron cerca de los 42°S, un área donde los diferentes tipos de playa (i.e., reflectivo, intermedio y disipativo) se producen a lo largo de las costas septentrionales de los archipiélagos chilenos. La variabilidad morfométrica de O. tuberculata, E. hirsuticauda y E. analoga se analizó mediante análisis de cluster y de componentes principales. Los resultados de este estudio mostraron que, independientemente del tipo de playa, los individuos de O. tuberculata que habitan playas próximas presentan una mayor similitud que con aquellas que habitan playas lejanas. Los individuos de E. analoga que habitan en el mismo tipo de playa mostraron una mayor similitud que con aquellas que habitan en diferentes tipos de playas. Estos resultados se discuten en relación con la zonificación a través del intermareal y la historia natural de estas especies.http://ref.scielo.org/rcysp

A multidisciplinary coastal vulnerability assessment for local government focused on ecosystems, Santa Barbara area, California

Incorporating coastal ecosystems in climate adaptation planning is needed to maintain the well-being of both natural and human systems. Our vulnerability study uses a multidisciplinary approach to evaluate climate change vulnerability of an urbanized coastal community that could serve as a model approach for communities worldwide, particularly in similar Mediterranean climates. We synthesize projected changes in climate, coastal erosion and flooding, watershed runoff and impacts to two important coastal ecosystems, sandy beaches and coastal salt marshes. Using downscaled climate models along with other regional models, we find that temperature, extreme heat events, and sea level are expected to increase in the future, along with more intense rainfall events, despite a negligible change in annual rainfall. Consequently, more droughts are expected but the magnitude of larger flood events will increase. Associated with the continuing rise of mean sea level, extreme coastal water levels will occur with increasingly greater magnitudes and frequency. Severe flooding will occur for both natural (wetlands, beaches) and built environments (airport, harbor, freeway, and residential areas). Adaptation actions can reduce the impact of rising sea level, which will cause losses of sandy beach zones and salt marsh habitats that support the highest biodiversity in these ecosystems, including regionally rare and endangered species, with substantial impacts occurring by 2050. Providing for inland transgression of coastal habitats, effective sediment management, reduced beach grooming and removal of shoreline armoring are adaptations that would help maintain coastal ecosystems and the beneficial services they provide