Long Term Decline of a Common Tern (Sterna hirundo) Population Nesting in Salt Marshes in Venice Lagoon, Italy

Wetlands ◽  
2010 ◽  
Vol 30 (6) ◽  
pp. 1153-1159 ◽  
Author(s):  
Francesco Scarton
2018 ◽  
Vol 88 (1) ◽  
pp. 23-32 ◽  
Author(s):  
Francesca Coccon ◽  
Stefano Borella ◽  
Nicola Simeoni ◽  
Stefano Malavasi

The Venice lagoon hosts the 15% of the entire Italian breeding population of Common terns, Sterna hirundo, highlighting the great value of the area for this species. However, in the last 25 years, a substantial decline of Common terns has been detected in the Lagoon, which culminated in 2008. The main causes of this negative trend were the loss of salt marsh habitats, where terns typically breed in the Venice lagoon. This was due to the increase in the mean sea level and the greater frequency of high tides during the reproductive period with consequent flooding of their breeding sites; competition with yellowlegged gulls (Larus michahellis), predation and human disturbance. As a preliminary experimental approach to counter the depletion of the species and favour its recovery, we performed a habitat loss compensation project by setting up four floating rafts (3x2m), covered by two different types of substrate (sandy and vegetal substrate). This was to function as an artificial nesting site safe from flooding, positioned in a protected internal wetland area of the Venice lagoon, Valle Averto (Sourthern Lagoon). We studied the colonization patterns of the rafts and the reproductive success of Common tern breeding pairs during the 2014 and 2015 breeding seasons. We also investigated those environmental and structural variables that could favour the use of the rafts and the nesting success of the species. In both years, the rafts were successfully colonized and used by terns for nesting. Our results also indicated higher temperature, lower rainfall and greater distance from the shore as the main habitat factors favouring the occurrence and the reproductive success of the breeding pairs, while a windrow of dead plants was indicated as the preferred substrate for covering rafts in order to make them more attractive. The results provided some suggestions for successful restoration plans to be developed in similar lagoon areas.


Acrocephalus ◽  
2019 ◽  
Vol 40 (180-181) ◽  
pp. 5-48
Author(s):  
Damijan Denac ◽  
Luka Božič

AbstractAn overview of the long-term (1980–2019) population development of colonial Laridae species in continental part of Slovenia, their nest sites at anthropogenic water bodies, and various conservation measures with special focus on Common Tern Sterna hirundo along the Slovenian/border part of the Drava River is given. Breeding of these species occurs only on the westernmost fringes of the Pannonian plain, on lowland floodplains of the main rivers of the Danube Basin. Altogether, breeding of Common Tern and Black-headed Gull Larus ridibundus was recorded at 11 and 10 sites, respectively. Lake Ptuj is the single site with mixed-species colony residing there in all years of the study period, while at Ormož (two sites) it was established during the early 1990s in the Slovenian territory but moved completely to the Croatian side by the second half of the 2010s. At all other sites, a suitable breeding habitat became available or was provided by management in just a few years, or created only recently. The percentage of Common Tern national population breeding in continental Slovenia was usually well above 50% throughout the 1980s and 1990s (52–136 pairs), while in the last 16 years (77–258 pairs) it ranged between 40.8% and 69.0%. Breeding of Black-headed Gull remains largely limited to continental Slovenia. Overall, continental populations of both species in the last few years have been substantially higher compared to the most of the study period. Long-term trends were estimated as a moderate increase for Common Tern and a strong increase for Black-headed Gull. Since 2006, the Mediterranean Gull L. melanocephalus has been a regular breeder at Lake Ptuj (up to 28 pairs), the only such site in Slovenia. Three general types of conservation measures implemented at different nesting locations are described in detail: (1) measures to create/increase the total surface of breeding habitat – the construction of new breeding structures, such as artificial islands and nesting rafts, (2) measures to maintain and enhance breeding habitat through recurring management activities, and (3) measures aimed to increase chick/nest survival and improve breeding success.


2002 ◽  
Author(s):  
Ian C. T. Nisbet
Keyword(s):  

2008 ◽  
Vol 44 (5) ◽  
Author(s):  
Simonetta Cola ◽  
Lorenzo Sanavia ◽  
Paolo Simonini ◽  
Bernhard A. Schrefler
Keyword(s):  

2021 ◽  
Vol 9 (4) ◽  
pp. 363
Author(s):  
Camilla Bertolini ◽  
Edouard Royer ◽  
Roberto Pastres

Effects of climatic changes in transitional ecosystems are often not linear, with some areas likely experiencing faster or more intense responses, which something important to consider in the perspective of climate forecasting. In this study of the Venice lagoon, time series of the past decade were used, and primary productivity was estimated from hourly oxygen data using a published model. Temporal and spatial patterns of water temperature, salinity and productivity time series were identified by applying clustering analysis. Phytoplankton and nutrient data from long-term surveys were correlated to primary productivity model outputs. pmax, the maximum oxygen production rate in a given day, was found to positively correlate with plankton variables measured in surveys. Clustering analysis showed the occurrence of summer heatwaves in 2008, 2013, 2015 and 2018 and three warm prolonged summers (2012, 2017, 2019) coincided with lower summer pmax values. Spatial effects in terms of temperature were found with segregation between confined and open areas, although the patterns varied from year to year. Production and respiration differences showed that the lagoon, despite seasonality, was overall heterotrophic, with internal water bodies having greater values of heterotrophy. Warm, dry years with high salinity had lower degrees of summer autotrophy.


2018 ◽  
Vol 10 (8) ◽  
pp. 1191 ◽  
Author(s):  
Luigi Tosi ◽  
Cristina Lio ◽  
Pietro Teatini ◽  
Tazio Strozzi

The use of satellite SAR interferometric methods has significantly improved the monitoring of ground movements over the last decades, thus opening new possibilities for a more accurate interpretation of land subsidence and its driving mechanisms. TerraSAR-X has been extensively used to study land subsidence in the Venice Lagoon, Italy, with the aim of quantifying the natural and anthropogenic causes. In this paper, we review and update the main results achieved by three research projects supported by DLR AOs (German Aerospace Center Announcement of Opportunity) and conducted to test the capability of TerraSAR-X PSI (Persistent Scatterer Interferometry) to detect ground movements in the complex physiographic setting of the Venice transitional coastal environment. The investigations have been focused on the historical center of Venice, the lagoon inlets where the MoSE is under construction, salt marshes, and newly built-up areas in the littoral. PSI on stacks of stripmap TerraSAR-X images covering short- to long-time periods (i.e., the years 2008–2009, 2008–2011 and 2008–2013) has proven particularly effective to measure land subsidence in the Venice coastland. The very high spatial resolution (3 m) and the short repeat time interval (11 days) of the TerraSAR-X acquisitions make it possible to investigate ground movements with a detail unavailable in the past. The interferometric products, properly calibrated, allowed for a millimetric vertical accuracy of the land movements at both the regional and local scales, even for short-term analyses, i.e., spanning one year only. The new picture of the land movement resulted from processing TerraSAR-X images has significantly contributed to update the knowledge on the subsidence process at the Venice coast.


Acrocephalus ◽  
2019 ◽  
Vol 40 (180-181) ◽  
pp. 79-92
Author(s):  
Al Vrezec ◽  
Urška Kačar

AbstractThe catalogue presents the data on all specimens of terns (Sterninae) that have been inventoried into the ornithological collection of the Slovenian Museum of Natural History (PMS). The catalogue includes data on preserved as well as lost specimens. The data have been collected from all inventory books at hand in the Slovenian Museum of Natural History. By the end of 2019, 66 different specimens of eight tern species have been recorded in the ornithological collection, of which 56 specimens are still preserved. Most specimens were collected in the 1940–1970 period. The largest number of specimens concerns the Black Tern Chlidonias niger and Common Tern Sterna hirundo. Among the collected terns, the specimens found in Slovenia predominate. Five specimens originate from other countries, specifically Eritrea, Oman, Serbia and Croatia.


1968 ◽  
Vol 41 (2) ◽  
pp. 210-219 ◽  
Author(s):  
Maryanne Robinson Hughes

Ecosystems ◽  
2019 ◽  
Vol 23 (3) ◽  
pp. 498-510
Author(s):  
Jessica L. O’Connell ◽  
Merryl Alber ◽  
Steven C. Pennings

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