scholarly journals Ecological status assessment and Non-Indigenous Species in industrial and fishing harbours of the Gulf of Gabès (central Mediterranean Sea)

2021 ◽  
Author(s):  
Nawfel Mosbahi ◽  
Jean-Philippe Pezy ◽  
Lassad Neifar ◽  
Jean-Claude Dauvin
Keyword(s):  
Biological Invasions ◽  
Ecological Status ◽  
Baseline Survey ◽  
Indigenous Species ◽  
Biotic Indices ◽  
Edaphic Factors ◽  
Gulf Of Gabes ◽  
Gulf Of Gabès ◽  
Non Indigenous Species ◽  
The Impact

Abstract This study from January to December 2018 was the first initiative of a Port Baseline Survey (PBS) aimed at assessing the impact of biological invasions in harbours of the Gulf of Gabès (GG). A total of 12 fishing and industrial harbours were seasonally prospected during 2018. A total of 174 macrobenthos taxa were recorded, belonging to eight zoological groups, with a dominance of crustaceans (32%), molluscs (31%) and polychaetes (20%). Among these taxa, 57 were Non-Indigenous Species (NIS) for Tunisian waters, while 27 species were recorded for the first time in GG harbours and three decapods ( Dyspanopeus sayi, Hippolyte prideauxiana and Pilumnus minutus ) and one amphipod ( Hamimaera hamigera ) were newly recorded from Tunisian waters. Two main categories of harbours are distinguished according to their macrobenthic communities and environmental features (essentially edaphic factors). The industrial harbours yield higher numbers of species and abundance of NIS than the fishing ports. The ALEX metric is used to evaluate the biological invasion status of the Gulf of Gabès harbours, showing that their status ranges from unaffected in fishing harbours to extremely affected in industrial harbours. Three biotic indices (AMBI, BO2A and BENTIX) are applied to assess the ecological status of harbours, which varies from moderate to good. ALEX and the other biotic indices are significantly correlated with harbour characteristics, maritime traffic and edaphic factors (organic matter and chemical contamination). The present study gives an overview of all available benthic data, the impact of biological invasions and the ecological quality status of harbours in the Gulf of Gabès. The results could be considered as providing important baseline data for the implementation of environmental policies and management plans in the future.

scholarly journals High diversified benthic habitats in a tidal Mediterranean sub-tropical environment: the case of the Gulf of Gabès (Tunisia)

2018 ◽  
Author(s):  
Abir Fersi ◽  
Nawfel Mosbahi ◽  
Ali Bakalem ◽  
Jean-Philippe Pezy ◽  
Alexandrine Baffreau ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Eastern Mediterranean ◽  
Tropical Environment ◽  
Gulf Of Gabes ◽  
Annual Cycles ◽  
Gulf Of Gabès ◽  
Zostera Noltei ◽  
Sediment Types ◽  
The Mediterranean ◽  
The Impact

The Gulf of Gabès on the southern coasts of Tunisia in the central part of the Mediterranean is a very shallow basin, characterized by semidiurnal tides, attaining a range of 2.3 m during spring tides. The intertidal zone was covered by extended Zostera (Zosterella) noltei Hornemann, 1832 beds mainly developed around the Kneiss Islands while tidal channels ensured the water circulation in this sub-tropical environment with very low freshwater input and high summer temperature. In spite of protected conventions, the area remained under high human pressures: overfishing, and the impact of the pollution of the phosphate industry. Intensive sampling in both intertidal and shallow subtidal zones during annual cycles permitted to identify a rich macrofauna which increase considerably the species known in this eastern part of the Mediterranean Sea. More than 50 species are added for the Tunisian fauna. Moreover, patterns of diversity are analysed with the sediment types, presence or absence of Zostera noltei seagrass bed, and human pressures. The list of the collected species are compared with those of surrounding areas in both Western and Eastern Mediterranean Sea.

scholarly journals Denitrification by benthic foraminifera and their contribution to N-loss from a fjord environment

2021 ◽  
Vol 18 (1) ◽  
pp. 327-341 ◽  
Author(s):  
Constance Choquel ◽  
Emmanuelle Geslin ◽  
Edouard Metzger ◽  
Helena L. Filipsson ◽  
Nils Risgaard-Petersen ◽  
...  
Keyword(s):  
Nitrogen Cycle ◽  
Benthic Foraminifera ◽  
Nitrate Removal ◽  
Nitrate Respiration ◽  
Indigenous Species ◽  
Overlying Water ◽  
Spatial And Temporal Scales ◽  
Chemical Gradients ◽  
Non Indigenous Species ◽  
The Impact

Abstract. Oxygen and nitrate availabilities impact the marine nitrogen cycle at a range of spatial and temporal scales. Here, we demonstrate the impact of denitrifying foraminifera on the nitrogen cycle at two oxygen and nitrate contrasting stations in a fjord environment (Gullmar Fjord, Sweden). Denitrification by benthic foraminifera was determined through the combination of specific density counting per microhabitat and specific nitrate respiration rates obtained through incubation experiments using N2O microsensors. Benthic nitrate removal was calculated from submillimeter chemical gradients extracted from 2D porewater images of the porewater nitrate concentration. These were acquired by combining the DET technique (diffusive equilibrium in thin film) with chemical colorimetry and hyperspectral imagery. Sediments with high nitrate concentrations in the porewater and oxygenated overlying water were dominated by the non-indigenous species (NIS) Nonionella sp. T1. Denitrification by this species could account for 50 %–100 % of the nitrate loss estimated from the nitrate gradients. In contrast sediments below hypoxic bottom waters had low inventories of porewater nitrate, and denitrifying foraminifera were rare. Their contribution to benthic nitrate removal was negligible (< 5 %). Our study showed that benthic foraminifera can be a major contributor to nitrogen mitigation in oxic coastal ecosystems and should be included in ecological and diagenetic models aiming to understand biogeochemical cycles coupled to nitrogen.

Assessing biological invasions in European Seas: Biological traits of the most widespread non-indigenous species

2018 ◽  
Vol 201 ◽  
pp. 17-28 ◽  
Author(s):  
Alice Cardeccia ◽  
Agnese Marchini ◽  
Anna Occhipinti-Ambrogi ◽  
Bella Galil ◽  
Stephan Gollasch ◽  
...  
Keyword(s):  
Biological Invasions ◽  
Biological Traits ◽  
Indigenous Species ◽  
Non Indigenous Species ◽  
European Seas

scholarly journals Biological invasions: winning the science battles but losing the conservation war?

Oryx ◽  
2003 ◽  
Vol 37 (2) ◽  
pp. 178-193 ◽  
Author(s):  
Philip E. Hulme
Keyword(s):  
Invasive Species ◽  
Biological Invasions ◽  
Global Environmental Change ◽  
Species Traits ◽  
Screening Tools ◽  
Indigenous Species ◽  
Invasion History ◽  
Invasion Process ◽  
Distribution Maps ◽  
Non Indigenous Species

Biological invasions by non-indigenous species (NIS) are widely recognized as a significant component of human-caused global environmental change. However, the standard programme of mapping distributions, predicting future ranges, modelling species spread, assessing impacts, developing management guidelines and screening species suffers from a number of serious limitations. NIS distribution maps can often be as misleading as they are instructive. Perceptions of the intensity, scale and rate of invasion are a function of mapping resolution, and the lack of common mapping standards prevents accurate comparative assessments. Coarse resolution data may overestimate the role of climate in the invasion process relative to other variables such as land use or human population density. Climate envelopes have therefore been widely used to predict species future ranges, but often overestimate potential distributions. Without an appropriate mechanistic understanding of the invasion process, correlative approaches may misinterpret the relative risks posed by different NIS. In addition, statistical models of invasion fail to encapsulate the complexity of human-mediated dispersal, which includes such diverse processes as transatlantic timber trade, horticultural fashion and the continuing expansion of road networks. Screening tools based on species traits, taxonomy and/or invasion history can sometimes result in high discrimination rates. Yet where the cost of false positives outweighs the risks from false negatives, a higher discriminatory power is required. Certain research outputs have perhaps been counterproductive in the war against invasive species. Studies have highlighted that only a tiny proportion of NIS are invasive, that most invasions occur in human dominated rather than pristine ecosystems, that indigenous and non-indigenous species are sufficiently similar that their impacts may not necessarily be different, and that there is evidence that introduced species augment rather than reduce species diversity. It is crucial to address these wider perceptions of the problem in order to mobilize the resources necessary for a global invasive species management programme.

Current and future threats from non-indigenous animal species in northern Australia: a spotlight on World Heritage Area Kakadu National Park

2007 ◽  
Vol 34 (6) ◽  
pp. 419 ◽  
Author(s):  
Corey J. A. Bradshaw ◽  
Iain C. Field ◽  
David M. J. S. Bowman ◽  
Chris Haynes ◽  
Barry W. Brook
Keyword(s):  
National Park ◽  
Animal Species ◽  
World Heritage ◽  
Effective Control ◽  
Indigenous Species ◽  
Northern Australia ◽  
World Heritage Area ◽  
Non Indigenous Species ◽  
The Impact ◽  
Heritage Area

Non-indigenous animal species threaten biodiversity and ecosystem stability by damaging or transforming habitats, killing or out-competing native species and spreading disease. We use World Heritage Area Kakadu National Park, northern Australia, as a focal region to illustrate the current and potential threats posed by non-indigenous animal species to internationally and nationally recognised natural and cultural values. Available evidence suggests that large feral herbivores such as Asian swamp buffalo, pigs and horses are the most ecologically threatening species in this region. This may reflect the inherent research bias, because these species are highly visible and impact primary production; consequently, their control has attracted the strongest research and management efforts. Burgeoning threats, such as the already established cane toad and crazy ant, and potentially non-indigenous freshwater fish, marine invertebrates and pathogens, may cause severe problems for native biodiversity. To counter these threats, management agencies must apply an ongoing, planned and practical approach using scientifically based and well funded control measures; however, many stakeholders require direct evidence of the damage caused by non-indigenous species before agreeing to implement control. To demonstrate the increasing priority of non-indigenous species research in Australia and to quantify taxonomic and habitat biases in research focus, we compiled an extensive biography of peer-reviewed articles published between 1950 and 2005. Approximately 1000 scientific papers have been published on the impact and control of exotic animals in Australia, with a strong bias towards terrestrial systems and mammals. Despite the sheer quantity of research on non-indigenous species and their effects, management responses remain largely ad hoc and poorly evaluated, especially in northern Australia and in high-value areas such as Kakadu National Park. We argue that improved management in relatively isolated and susceptible tropical regions requires (1) robust quantification of density–damage relationships, and (2) the delivery of research findings that stimulate land managers to develop cost-effective control and monitoring programs.

scholarly journals High diversified benthic habitats in a tidal Mediterranean sub-tropical environment: the case of the Gulf of Gabès (Tunisia)

2018 ◽  
Author(s):  
Abir Fersi ◽  
Nawfel Mosbahi ◽  
Ali Bakalem ◽  
Jean-Philippe Pezy ◽  
Alexandrine Baffreau ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Eastern Mediterranean ◽  
Tropical Environment ◽  
Gulf Of Gabes ◽  
Annual Cycles ◽  
Gulf Of Gabès ◽  
Zostera Noltei ◽  
Sediment Types ◽  
The Mediterranean ◽  
The Impact

The Gulf of Gabès on the southern coasts of Tunisia in the central part of the Mediterranean is a very shallow basin, characterized by semidiurnal tides, attaining a range of 2.3 m during spring tides. The intertidal zone was covered by extended Zostera (Zosterella) noltei Hornemann, 1832 beds mainly developed around the Kneiss Islands while tidal channels ensured the water circulation in this sub-tropical environment with very low freshwater input and high summer temperature. In spite of protected conventions, the area remained under high human pressures: overfishing, and the impact of the pollution of the phosphate industry. Intensive sampling in both intertidal and shallow subtidal zones during annual cycles permitted to identify a rich macrofauna which increase considerably the species known in this eastern part of the Mediterranean Sea. More than 50 species are added for the Tunisian fauna. Moreover, patterns of diversity are analysed with the sediment types, presence or absence of Zostera noltei seagrass bed, and human pressures. The list of the collected species are compared with those of surrounding areas in both Western and Eastern Mediterranean Sea.

scholarly journals Bryozoa from the Mediterranean coast of Israel

2016 ◽  
Vol 17 (2) ◽  
pp. 440 ◽  
Author(s):  
N. SOKOLOVER ◽  
P. D. TAYLOR ◽  
M. ILAN
Keyword(s):  
Eastern Mediterranean ◽  
Mediterranean Coast ◽  
Indigenous Species ◽  
Baseline Information ◽  
Higher Temperature ◽  
The Mediterranean ◽  
1960S And 1970S ◽  
The 1960S ◽  
Non Indigenous Species ◽  
The Impact

The impact of global warming on the composition of marine biotas is increasing, underscoring the need for better baseline information on the species currently present in given areas. Little is known about the bryozoan fauna of Israel; the most recent publication concerning species from the Mediterranean coast was based on samples collected in the 1960s and 1970s. Since that time, not only have the species present in this region changed, but so too has our understanding of bryozoan taxonomy. Here we use samples collected during the last decade to identify 47 bryozoan species, of which 15 are first records for the Levantine basin. These include one new genus and species (Crenulatella levantinensis gen. et. sp. nov.), two new species (Licornia vieirai sp. nov. and Trematooecia mikeli sp. nov.), and two species that may be new but for which available material is inadequate for formal description (Reteporella sp. and Thalamoporella sp.). In addition, Conopeum ponticum is recorded for the first time from the Mediterranean Sea. Non-indigenous species make up almost one-quarter of the 47 species identified. All of the non-indigenous species are native to tropical and subtropical regions, implying a change of the Levant bryozoan biota from a temperate to a more tropical state, probably related to both higher temperature and salinity and to the opening of the Suez Canal connecting the Red Sea and the Eastern Mediterranean.  

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