Variations in Posidonia oceanica meadow structure along the coast of the Dugi Otok Island (eastern Adriatic Sea)

2008 ◽  
Vol 88 (5) ◽  
pp. 883-892 ◽  
Author(s):  
Petar Kru΂ić
Keyword(s):  
Adriatic Sea ◽  
Structural Characteristics ◽  
Outer Part ◽  
Posidonia Oceanica ◽  
Shoot Density ◽  
The Other ◽  
Impact Factors ◽  
Index Number ◽  
Area Index ◽  
The Status

Although the anthropogenic impact on Posidonia oceanica meadows in the Mediterranean Sea has been studied over the last few decades, the data about the status of this endemic magnoliophyte are scarcer from the Adriatic Sea. Samples of P. oceanica meadows were collected in June and July 2004 using SCUBA diving at 8 sites in the area of the Dugi Otok Island, all at depths of 10 m. The meadow's shoot density was measured, and shoots were collected to be examined and compared through number of leaves per shoot, leaf surface per shoot, leaf area index, number and biomass of taxa of epiphytic flora. Significant differences in P. oceanica meadow structure were found among investigated sites, especially between sites in the vicinity of the fish farm and the other sites. Meadow density decreased at sites in the Dugi Otok channel and the main impact factors seem to be the input of organic matter, originating from the fish cages and sewage input. These human activities are a source of nutrient pollution and stimulate blooms of phytoplankton and higher algae. The sea grass meadow vitality seems to be more negatively affected in the channel. The highest values of shoot density were recorded at investigated sites VR and ME at the outer part of the Dugi Otok Island. The shoot density was very low at site FU, situated in the channel. Biomass of the epiphytic algae exhibited the highest values at the site FU, while at the other investigated sites the values were significantly lower. Concerning the epiphytic macroflora, a total of 55 taxa of epiphytic macroalgae were identified and the class Rhodophyta dominated in all samples. The present study shows the high differences in morphological and structural characteristics of Posidonia oceanica meadows among various sites with and without anthropogenic influence.

scholarly journals Monitoring of marine phanerogams’ habitats and assessment of areas exposed to anchoring in the International Marine Park of Bonifacio (Sardinia Area)

2015 ◽  
Author(s):  
Andrea Cossu ◽  
Mario De Luca ◽  
Yuri Donno
Keyword(s):  
Direct Method ◽  
Structural Characteristics ◽  
Ecological Status ◽  
Posidonia Oceanica ◽  
Monitoring And Control ◽  
Area Index ◽  
Marine Park ◽  
Minimum Requirements ◽  
Marine Areas ◽  
The Impact

The International Marine Park of the Strait of Bonifacio and the National Park of La Maddalena have started a series of investigations in the marine areas under their jurisdiction. Through the European project, GECT (European Group of Territorial Cooperation), studies have been carried out to define the type, the structural characteristics of the Posidonia oceanica seagrass and to evaluate the impact of dropping anchors. The study, carried out by a team of experts from the institutions named above, used shared methodologies in relation to the same type of challenges and problems. The study areas on the Sardinian side were Passo Asinelli pass, Porto della Madonna harbor and Cala Portese cove. For each site two stations were identified, a monitoring and a control one. The type of meadow, its morphological and structural characteristics (matte, rocks, degree of fragmentation, height of matte, etc.) and the possible presence of marks/signs caused by the dropping of anchors were assessed in selected areas. The compactness of the matte, estimated using a penetrometer, the percentage of seabed covered by the plant and density were assessed by direct method by divers. The results for the leaf density show the meadows are in regression; however, there are better conditions in Porto Madonna where the monitoring and control stations show density near to normal values. Particularly low values were measured in Passo Asinelli where, despite prohibitions, the high pressure of tourism generates stress to the plant formation. The leaf standing crop, the leaf area index and measures penetrometric lead to conclusions almost similar indicating best ecological conditions in Porto Madonna, confirming previous results. The indicators used show an ecological status of lesser quality for the sites of both Passo Asinelli and, more visible, of Cala Portese. Porto Madonna, on the other hand, shows values equal to the minimum requirements for a meadow surface.

scholarly journals Patch types in Posidonia oceanica meadows around Corsica: How can we use them in seascape ecology?

2015 ◽  
Author(s):  
Arnaud Abadie ◽  
Marina Bonacorsi ◽  
Sylvie Gobert ◽  
Pierre Lejeune ◽  
Gérard Pergent ◽  
...  
Keyword(s):  
Large Scale ◽  
Water Movement ◽  
Human Impacts ◽  
Structural Characteristics ◽  
Posidonia Oceanica ◽  
Radius Of Gyration ◽  
Index Number ◽  
Fish Farms ◽  
Patch Type ◽  
Seagrass Meadows

The meadows formed by the Mediterranean seagrass Posidonia oceanica are subjected to various natural (e.g., water movement, light availability, sedimentation) and anthropogenic (e.g., anchoring, trawling, fish farms, explosives) phenomena that erode them and create diverse types of patches. The assemblage of the P. oceanica matrix and these patches creates particular seascapes. On the basis of this assessment, we aimed to investigate the importance of the patch type in structuring P. oceanica seascapes and to offer new prospects in the large scale studies of seagrass meadows. Five sites encompassing large P. oceanica meadows ranging from 1.86 km² to 4.42 km² along the Corsican coast (France) were considered. Eleven patch types with different sizes, shapes and origins were identified using side scan sonar images (sonograms). Five were recognized as natural and five as anthropogenic. One can be of both origins. The resolution of the sonograms allowed to detect patches of various sizes ranging from 1 m² to 111 829 m². The relation between structural characteristics of patches and the whole seascape aspect was explored using seven landscape metrics relevant for the study of meadows patchiness (patch area, mean radius of gyration, area-weighted radius of gyration, coefficient of variation of the Euclidean nearest-neighbor distance, area-weighted perimeter-area ratio, landscape division index, number of patches). Only a small number of patch types appears to play the strongest role in the characterization of the P. oceanica seascapes. Furthermore, the use of seascape structures seems to be suitable for the development of new tools like indices for the assessment of human impacts on P. oceanica meadows. In this perspective we propose a new and simple index, the Patchiness Source Index (PaSI), to estimate the origin of the patchiness (natural or anthropogenic) for a given area. A landscape approach, as well as information on patch dynamic, should be integrated in the new indices that aim to assess the state of conservation of the whole P. oceanica ecosystem.

scholarly journals Assessment of Posidonia oceanica status along the north Croatian coast (Adriatic Sea)

2015 ◽  
Author(s):  
Ivan Guala ◽  
Ljiljana Iveša ◽  
Patrik Krstinić ◽  
Zrinka Jakl ◽  
Milena Šijan ◽  
...  
Keyword(s):  
Lower Limit ◽  
Adriatic Sea ◽  
Posidonia Oceanica ◽  
Shoot Density ◽  
Monitoring Programme ◽  
Habitats Directive ◽  
Anthropogenic Factors ◽  
Northern Adriatic ◽  
National Monitoring ◽  
The North

Monitoring of Posidonia oceanica was carried out in the framework of the MedMPAnet Project in eight meadows not formerly explored in an area along the north coast of Croatia (Primorje-Gorski Kotar County, Northern Adriatic Sea). The survey was aimed to collect preliminary data as a baseline for future surveillance cycles of the priority habitat 1120 "Posidonia beds" within the framework of the National Monitoring Programme, according to the requirements of the EU Habitats Directive. Fieldwork was carried out in 2013 and 2014 through direct SCUBA diving surveys. At each site, general information on coastal features and potential human pressures was recorded and the following descriptors of meadow conditions were assessed at three depth ranges: shoot density, percent coverage of Posidonia oceanica, dead matte and substrate type; depth and type of lower limits were also recorded for each meadow. Two meadows, located in the island of Rab (Uvala Planka and Frkanj), were investigated during both years of survey in order to test any differences due to the methodological approach we used. Overall, results indicated signs of distress for several meadows. Density ranged from 355±22 to 629±21 shoot per m2 at shallow stations (<10 m depth), from 141±8 to 324±23 shoot per m2 at intermediate depth (about 15 m), and from 79±5 to 157±10 shoot per m2 at the lower limit. Regression was also testified by high coverage of dead matte (locally >40%) especially at the lower limit, which was regressive in four meadows and in no case did it exceed 27 meters in depth. The temporal comparison provided consistent results between the two years for investigation of shoot density, at all sites and throughout the bathymetric range. However, some changes were detected in the deepest portions of both meadows in the coverage of Posidonia oceanica (lower than 50% in 2014). Further monitoring and research campaigns are recommended to improve the level of knowledge on the status of meadows in this area, to develop a baseline for assessing trends on a long-term temporal scale as requested by Habitats Directive, and to shed light on the relevance of both environmental and anthropogenic factors in determining the health status of the meadows. Intercalibration among operators is also suggested to ensure reliable data in implementing the National Monitoring Programme.

Posidonia oceanica lower depth limits along a latitudinal gradient in the eastern Adriatic Sea

2020 ◽  
Vol 63 (3) ◽  
pp. 209-214
Author(s):  
Ivana Zubak ◽  
Hrvoje Cizmek ◽  
Melita Mokos
Keyword(s):  
Latitudinal Gradient ◽  
Depth Distribution ◽  
Adriatic Sea ◽  
Environmental Changes ◽  
Marine Species ◽  
Posidonia Oceanica ◽  
Shoot Density ◽  
Eastern Coast ◽  
Depth Limit ◽  
Lower Depth

AbstractAlthough extensive studies have been made on Posidonia oceanica ecosystems, in terms of their phenological characteristics, shoot density, biomass, and associated faunal assemblages, little attention has been given to the depth distribution of this species in the Adriatic Sea. The depth limits of the Mediterranean endemic seagrass P. oceanica growing along the eastern coast of the Croatian Adriatic Sea were examined by the use of SCUBA diving. Fifty-two independent measurements show that the lower depth limit of P. oceanica in the Croatian Adriatic Sea ranges from 24 m in the north to 36 m in the south, with a strong latitudinal gradient. The information on maximum depth distribution is an important asset when the increased human pressure and rapid environmental changes pose a threat to the survival of this slow-growing marine species.

scholarly journals Assessment of Posidonia oceanica status along the north Croatian coast (Adriatic Sea)

2015 ◽  
Author(s):  
Ivan Guala ◽  
Ljiljana Iveša ◽  
Patrik Krstinić ◽  
Zrinka Jakl ◽  
Milena Šijan ◽  
...  
Keyword(s):  
Lower Limit ◽  
Adriatic Sea ◽  
Posidonia Oceanica ◽  
Shoot Density ◽  
Monitoring Programme ◽  
Habitats Directive ◽  
Anthropogenic Factors ◽  
Northern Adriatic ◽  
National Monitoring ◽  
The North

Monitoring of Posidonia oceanica was carried out in the framework of the MedMPAnet Project in eight meadows not formerly explored in an area along the north coast of Croatia (Primorje-Gorski Kotar County, Northern Adriatic Sea). The survey was aimed to collect preliminary data as a baseline for future surveillance cycles of the priority habitat 1120 "Posidonia beds" within the framework of the National Monitoring Programme, according to the requirements of the EU Habitats Directive. Fieldwork was carried out in 2013 and 2014 through direct SCUBA diving surveys. At each site, general information on coastal features and potential human pressures was recorded and the following descriptors of meadow conditions were assessed at three depth ranges: shoot density, percent coverage of Posidonia oceanica, dead matte and substrate type; depth and type of lower limits were also recorded for each meadow. Two meadows, located in the island of Rab (Uvala Planka and Frkanj), were investigated during both years of survey in order to test any differences due to the methodological approach we used. Overall, results indicated signs of distress for several meadows. Density ranged from 355±22 to 629±21 shoot per m2 at shallow stations (<10 m depth), from 141±8 to 324±23 shoot per m2 at intermediate depth (about 15 m), and from 79±5 to 157±10 shoot per m2 at the lower limit. Regression was also testified by high coverage of dead matte (locally >40%) especially at the lower limit, which was regressive in four meadows and in no case did it exceed 27 meters in depth. The temporal comparison provided consistent results between the two years for investigation of shoot density, at all sites and throughout the bathymetric range. However, some changes were detected in the deepest portions of both meadows in the coverage of Posidonia oceanica (lower than 50% in 2014). Further monitoring and research campaigns are recommended to improve the level of knowledge on the status of meadows in this area, to develop a baseline for assessing trends on a long-term temporal scale as requested by Habitats Directive, and to shed light on the relevance of both environmental and anthropogenic factors in determining the health status of the meadows. Intercalibration among operators is also suggested to ensure reliable data in implementing the National Monitoring Programme.

scholarly journals Patch types in Posidonia oceanica meadows around Corsica: How can we use them in seascape ecology?

2015 ◽  
Author(s):  
Arnaud Abadie ◽  
Marina Bonacorsi ◽  
Sylvie Gobert ◽  
Pierre Lejeune ◽  
Gérard Pergent ◽  
...  
Keyword(s):  
Large Scale ◽  
Water Movement ◽  
Human Impacts ◽  
Structural Characteristics ◽  
Posidonia Oceanica ◽  
Radius Of Gyration ◽  
Index Number ◽  
Fish Farms ◽  
Patch Type ◽  
Seagrass Meadows

The meadows formed by the Mediterranean seagrass Posidonia oceanica are subjected to various natural (e.g., water movement, light availability, sedimentation) and anthropogenic (e.g., anchoring, trawling, fish farms, explosives) phenomena that erode them and create diverse types of patches. The assemblage of the P. oceanica matrix and these patches creates particular seascapes. On the basis of this assessment, we aimed to investigate the importance of the patch type in structuring P. oceanica seascapes and to offer new prospects in the large scale studies of seagrass meadows. Five sites encompassing large P. oceanica meadows ranging from 1.86 km² to 4.42 km² along the Corsican coast (France) were considered. Eleven patch types with different sizes, shapes and origins were identified using side scan sonar images (sonograms). Five were recognized as natural and five as anthropogenic. One can be of both origins. The resolution of the sonograms allowed to detect patches of various sizes ranging from 1 m² to 111 829 m². The relation between structural characteristics of patches and the whole seascape aspect was explored using seven landscape metrics relevant for the study of meadows patchiness (patch area, mean radius of gyration, area-weighted radius of gyration, coefficient of variation of the Euclidean nearest-neighbor distance, area-weighted perimeter-area ratio, landscape division index, number of patches). Only a small number of patch types appears to play the strongest role in the characterization of the P. oceanica seascapes. Furthermore, the use of seascape structures seems to be suitable for the development of new tools like indices for the assessment of human impacts on P. oceanica meadows. In this perspective we propose a new and simple index, the Patchiness Source Index (PaSI), to estimate the origin of the patchiness (natural or anthropogenic) for a given area. A landscape approach, as well as information on patch dynamic, should be integrated in the new indices that aim to assess the state of conservation of the whole P. oceanica ecosystem.

scholarly journals Monitoring of marine phanerogams’ habitats and assessment of areas exposed to anchoring in the International Marine Park of Bonifacio (Sardinia Area)

2015 ◽  
Author(s):  
Andrea Cossu ◽  
Mario De Luca ◽  
Yuri Donno
Keyword(s):  
Direct Method ◽  
Structural Characteristics ◽  
Ecological Status ◽  
Posidonia Oceanica ◽  
Monitoring And Control ◽  
Area Index ◽  
Marine Park ◽  
Minimum Requirements ◽  
Marine Areas ◽  
The Impact

The International Marine Park of the Strait of Bonifacio and the National Park of La Maddalena have started a series of investigations in the marine areas under their jurisdiction. Through the European project, GECT (European Group of Territorial Cooperation), studies have been carried out to define the type, the structural characteristics of the Posidonia oceanica seagrass and to evaluate the impact of dropping anchors. The study, carried out by a team of experts from the institutions named above, used shared methodologies in relation to the same type of challenges and problems. The study areas on the Sardinian side were Passo Asinelli pass, Porto della Madonna harbor and Cala Portese cove. For each site two stations were identified, a monitoring and a control one. The type of meadow, its morphological and structural characteristics (matte, rocks, degree of fragmentation, height of matte, etc.) and the possible presence of marks/signs caused by the dropping of anchors were assessed in selected areas. The compactness of the matte, estimated using a penetrometer, the percentage of seabed covered by the plant and density were assessed by direct method by divers. The results for the leaf density show the meadows are in regression; however, there are better conditions in Porto Madonna where the monitoring and control stations show density near to normal values. Particularly low values were measured in Passo Asinelli where, despite prohibitions, the high pressure of tourism generates stress to the plant formation. The leaf standing crop, the leaf area index and measures penetrometric lead to conclusions almost similar indicating best ecological conditions in Porto Madonna, confirming previous results. The indicators used show an ecological status of lesser quality for the sites of both Passo Asinelli and, more visible, of Cala Portese. Porto Madonna, on the other hand, shows values equal to the minimum requirements for a meadow surface.

scholarly journals Assessment of Posidonia oceanica status along the north Croatian coast (Adriatic Sea)

2015 ◽  
Author(s):  
Ivan Guala ◽  
Ljiljana Iveša ◽  
Patrik Krstinić ◽  
Zrinka Jakl ◽  
Milena Šijan ◽  
...  
Keyword(s):  
Lower Limit ◽  
Adriatic Sea ◽  
Posidonia Oceanica ◽  
Shoot Density ◽  
Monitoring Programme ◽  
Habitats Directive ◽  
Anthropogenic Factors ◽  
Northern Adriatic ◽  
National Monitoring ◽  
The North

Monitoring of Posidonia oceanica was carried out in the framework of the MedMPAnet Project in eight meadows not formerly explored in an area along the north coast of Croatia (Primorje-Gorski Kotar County, Northern Adriatic Sea). The survey was aimed to collect preliminary data as a baseline for future surveillance cycles of the priority habitat 1120 "Posidonia beds" within the framework of the National Monitoring Programme, according to the requirements of the EU Habitats Directive. Fieldwork was carried out in 2013 and 2014 through direct SCUBA diving surveys. At each site, general information on coastal features and potential human pressures was recorded and the following descriptors of meadow conditions were assessed at three depth ranges: shoot density, percent coverage of Posidonia oceanica, dead matte and substrate type; depth and type of lower limits were also recorded for each meadow. Two meadows, located in the island of Rab (Uvala Planka and Frkanj), were investigated during both years of survey in order to test any differences due to the methodological approach we used. Overall, results indicated signs of distress for several meadows. Density ranged from 355±22 to 629±21 shoot per m2 at shallow stations (<10 m depth), from 141±8 to 324±23 shoot per m2 at intermediate depth (about 15 m), and from 79±5 to 157±10 shoot per m2 at the lower limit. Regression was also testified by high coverage of dead matte (locally >40%) especially at the lower limit, which was regressive in four meadows and in no case did it exceed 27 meters in depth. The temporal comparison provided consistent results between the two years for investigation of shoot density, at all sites and throughout the bathymetric range. However, some changes were detected in the deepest portions of both meadows in the coverage of Posidonia oceanica (lower than 50% in 2014). Further monitoring and research campaigns are recommended to improve the level of knowledge on the status of meadows in this area, to develop a baseline for assessing trends on a long-term temporal scale as requested by Habitats Directive, and to shed light on the relevance of both environmental and anthropogenic factors in determining the health status of the meadows. Intercalibration among operators is also suggested to ensure reliable data in implementing the National Monitoring Programme.

The integrated interventional radiology match: a bibliometric analysis of matched first-year residents

2019 ◽  
Vol 3 ◽  
pp. 13 ◽  
Author(s):  
Vishnu Chandra ◽  
Neil Jain ◽  
Pratik Shukla ◽  
Ethan Wajswol ◽  
Sohail Contractor ◽  
...  
Keyword(s):  
Interventional Radiology ◽  
Bibliometric Analysis ◽  
Statistical Significance ◽  
Univariate Analysis ◽  
Impact Factors ◽  
Index Number ◽  
Research Information ◽  
H Index ◽  
Scopus Database ◽  
Journal Impact

Objectives: The integrated interventional radiology (IR) residency has only been established relatively recently as compared to other specialties. Although some preliminary information is available based on survey data five, no comprehensive bibliometric analysis documenting the importance of the quantity and quality of research in applying to an integrated-IR program currently exists. As the first bibliometric analysis of matched IR residents, the data obtained from this study fills a gap in the literature. Materials and Methods: A list of matched residents from the 2018 integrated-IR match were identified by contacting program directors. The Scopus database was used to search for resident research information, including total publications, first-author publications, radiology-related publications, and h-indices. Each matriculating program was categorized into one of five tiers based on the average faculty Hirsch index (h-index). Results: Sixty-three programs and 117 matched residents were identified and reviewed on the Scopus database. For the 2018 cycle, 274 total publications were produced by matched applicants, with a mean of 2.34 ± 0.41 publication per matched applicant. The average h-index for matched applicants was 0.96 ± 0.13. On univariate analysis, the number of radiology-related publications, highest journal impact factor, and h-index were all associated with an increased likelihood of matching into a higher tier program (P < 0.05). Other research variables displayed no statistical significance. All applicants with PhDs matched into tier one programs. Conclusions: Research serves as an important element in successfully matching into an integrated-IR residency. h-index, number of radiology-related manuscripts, and highest journal impact factors are all positively associated with matching into a higher tier program.

Status of Family Fissidentaceae in Gujarat

2016 ◽  
Vol 1 (1) ◽  
Author(s):  
D.G. Shah ◽  
D.N. Mehta ◽  
R.V. Gujar
Keyword(s):  
Distinct Species ◽  
The State ◽  
The Other ◽  
Land Plants ◽  
Reproductive Structures ◽  
The Family ◽  
The Status ◽  
Vegetative Characters ◽  
First Time ◽  
Different Parts

Bryophytes are the second largest group of land plants and are also known as the amphibians of the plant kingdom. 67 species of bryophytes have been reported from select locations across the state of Gujrat. The status of family fissidentaceae which is a large moss family is being presented in this paper. Globally the family consists of 10 genera but only one genus, Fissidens Hedw. has been collected from Gujarat. Fissidens is characterized by a unique leaf structure and shows the presence of three distinct lamina, the dorsal, the ventral and the vaginant lamina. A total of 8 species of Fissidens have been reported from the state based on vegetative characters as no sporophyte stages were collected earlier. Species reported from the neighboring states also showed the absence of sporophytes. The identification of different species was difficult due to substantial overlap in vegetative characters. Hence a detailed study on the diversity of members of Fissidentaceae in Gujarat was carried out between November 2013 and February 2015. In present study 8 distinct species of Fissidens have been collected from different parts of the state. Three species Fissidens splachnobryoides Broth., Fissidens zollingerii Mont. and Fissidens curvato-involutus Dixon. have been identified while the other five are still to be identified. Fissidens zollingerii Mont. and Fissidens xiphoides M. Fleisch., which have been reported as distinct species are actually synonyms according to TROPICOS database. The presence of sexual reproductive structures and sporophytes for several Fissidens species are also being reported for the first time from the state.

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