Seahorse (Hippocampinae) population fluctuations in the Ria Formosa Lagoon, south Portugal

2015 ◽  
Vol 87 (3) ◽  
pp. 679-690 ◽  
Author(s):  
M. Correia ◽  
I. R. Caldwell ◽  
H. J. Koldewey ◽  
J. P. Andrade ◽  
J. Palma
Keyword(s):  
Population Fluctuations ◽  
Ria Formosa ◽  
South Portugal

scholarly journals Monitoring of Seahorse Populations, in the Ria Formosa Lagoon (Portugal), Reveals Steep Fluctuations: Potential Causes and Future Mitigations

2021 ◽  
Author(s):  
Miguel Correia
Keyword(s):  
Natural Habitat ◽  
Current Status ◽  
Population Fluctuations ◽  
Illegal Fishing ◽  
Hippocampus Guttulatus ◽  
Ria Formosa ◽  
Caulerpa Prolifera ◽  
South Portugal ◽  
Local Extirpation ◽  
The Impact

AbstractAfter seahorse population fluctuations were revealed in previous studies, probably due to changes in their natural habitat, this study sought to determine the current status of the populations of the two existing seahorse species in the Ria Formosa lagoon, by revisiting previously surveyed sites, while assessing the main drivers for detected changes. Hippocampus guttulatus densities decreased significantly between 2002 and 2008, followed by a significant increase between 2008 and 2012 and a significant decrease between 2012 and 2018. There were no significant differences in H. guttulatus populations between the 2002 and 2012 surveys, and between 2008 and 2018. As for Hippocampus hippocampus, there were no significant differences comparing densities from all the different dates. Among the different variables tested in this study, holdfast coverage seems to have played a crucial role in seahorse decline. It is important to further assess the impact on seahorse populations of two recently reported events, the illegal fishing of seahorses and the expansion of Caulerpa prolifera algae in the Ria Formosa lagoon, South Portugal. Considering the existent threats and the probable causes behind the recent seahorse abundance decline, seahorses’ low densities make them even more susceptible to local extirpation due to continuous threats, which emphasizes the dire urgency to put in place mitigative actions to contribute to the conservation of these iconic species.

Salt marshes adjustment to anthropogenic pressures and sea-level rise

2021 ◽  
Author(s):  
A. Rita Carrasco ◽  
Katerina Kombiadou ◽  
Miguel Amado
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Salt Marshes ◽  
Anthropogenic Pressures ◽  
The Past ◽  
Ria Formosa ◽  
Sediment Loads ◽  
Human Interventions ◽  
South Portugal ◽  
And Sea Level

<p>It is predictable that salt marshes in regions, where sediment loads are high, should be stable against a broader range of relative sea level scenarios than those in sediment-poor systems. Despite extensive theoretical and laboratory studies, additional syntheses of marsh ‘persistence’ indicators under human interventions and accelerated sea-level rise rates are still needed. This study investigates the recent lateral changes occurring in lagoon-type marshes of the Ria Formosa lagoon (south Portugal) in the presence of human interventions and sea-level rise, to identify the major drivers for past marsh evolution and to estimate potential future trends. The conducted analysis assessed the past geomorphological adjustment based on imagery analysis and assessed its potential future adjustment to sea-level rise (~100 years) based on modelled land cover changes (by employing the SLAMM model within two sea-level rise scenarios).</p><p>Salt marshes in the Ria Formosa showed slow lateral growth rates over the last 70 years (<1 mm∙yr<sup>-1</sup>), with localized erosion along the main navigable channels associated with dredging activities. Higher change rates were noted near the inlets, with stronger progradation near the natural inlets of the system, fed by sediment influx pulses. Any potential influence of sea-level increase to an intensification of marsh-edge erosion in the past, could not be distinguished from human-induced pressures in the area. No significant sediment was exchanged between the salt marshes and tidal flats, and no self-organization pattern between them was observed in past. The related analysis showed that landcover changes in the salt marsh areas are likely to be more prominent in the future. The obtained results showed evidence of non-linearity in marsh response to high sea-level rise rates, which could indicate to the presence of critical thresholds and potential negative feedbacks within the system, with significant implications to marsh resilience.</p>

scholarly journals Discerning natural and anthropogenic organic matter inputs to salt marsh sediments of Ria Formosa lagoon (South Portugal)

2020 ◽  
Vol 27 (23) ◽  
pp. 28962-28985
Author(s):  
Mukesh Kumar ◽  
Tomasz Boski ◽  
Francisco J. González-Vila ◽  
José Mª de la Rosa ◽  
José A. González-Pérez
Keyword(s):  
Organic Matter ◽  
Salt Marsh ◽  
Ria Formosa ◽  
Marsh Sediments ◽  
Salt Marsh Sediments ◽  
South Portugal

scholarly journals Biogeochemical modelling of Ria Formosa (South Portugal)

Hydrobiologia ◽  
2008 ◽  
Vol 611 (1) ◽  
pp. 115-132 ◽  
Author(s):  
P. Duarte ◽  
B. Azevedo ◽  
M. Guerreiro ◽  
C. Ribeiro ◽  
R. Bandeira ◽  
...  
Keyword(s):  
Ria Formosa ◽  
South Portugal

First record of the Mediterranean parrotfish, Sparisoma cretense in Ria Formosa (south Portugal)

2008 ◽  
Vol 1 ◽  
Author(s):  
David Abecasis ◽  
Luís Bentes ◽  
Joaquim Ribeiro ◽  
Daniel Machado ◽  
Frederico Oliveira ◽  
...  
Keyword(s):  
First Record ◽  
Ria Formosa ◽  
The Mediterranean ◽  
South Portugal

scholarly journals Biomass and leaf dynamics of Cymodocea nodosa in the Ria Formosa lagoon, South Portugal

2007 ◽  
Vol 50 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Alexandra H. Cunha ◽  
Carlos M. Duarte
Keyword(s):  
Cymodocea Nodosa ◽  
Ria Formosa ◽  
South Portugal ◽  
Leaf Dynamics
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