Seagrass Distribution Research Articles

Growth indicator response of Zostera japonica under different salinity and turbidity stresses in the Yellow River Estuary, China

Estuaries are special geographical units of sea and land alternation, and are sensitive to changes in environmental factors. Zostera japonica is a very widespread seagrass species in the Yellow River Estuary, China and seagrass beds consisted of them are important estuary ecosystem resources. Water and sediment regulation at the Xiaolangdi Reservoir on the Yellow River can change the water environment in the estuary and threaten seagrass distribution. We evaluated the salinity and turbidity stress on Z. japonica by site sampling and laboratory tests, and compared both sets of growth conditions. We then set turbidity and salinity gradients to quantify the variation in sediment and salinity conditions imposed by the water and sediment regulation. Results showed that changes in Z. japonica biomass can be used as a stress indicator. Salinity levels of 20 ppt and turbidity levels below 50 NTU were the most suitable for growth. Biomass decreased as turbidity increased. At high turbidity (> 100 NTU), growth in low salinity (< 20 ppt) was significantly better than at high salinity (> 25 ppt). The rank of inhibitory effect of salinity, turbidity and interactive salinity–turbidity treatment on the juvenile stage was salinity > salinity–turbidity interaction > turbidity. The rank of inhibitory effect on the mature stage was turbidity > salinity–turbidity interaction > salinity. Salinity inhibited growth at the juvenile stage, while turbidity inhibited growth at the mature stage. Our research suggested that Z. japonica can adapt to resist the stress of changing salinity and turbidity, and this has great significance to the sustainability of the seagrass bed in the Yellow River Estuary.

Seagrass distribution using remote sensing along the Ujunggenteng Coastal, Sukabumi

Seagrass beds play an important role in marine ecosystems, primarily as a habitat that supports marine life. This study was undertaken to address the lack of available research regarding changes in seagrass density from year to year along the Ujunggenteng coastal, which is necessary to preserve seagrass beds in this area. More specifically, the purpose of this study was to determine the distribution of seagrass beds along the Ujunggenteng coastal and analyze their physical characteristics over a sixteen year period, from 2000–2016. The method used remote sensing technology that is used to look at the distribution of seagrass beds by performing calculations based on Lyzenga algorithms. Based on the results of data processing, seagrass in the study area was found to be distributed on three coral reefs. From year to year, the area of seagrass along the Ujunggenteng coastal appeared to increase. The physical characteristics affecting the distribution of seagrass along the Ujunggenteng coastal wered found to be sea surface temperature, salinity, and depth of sea water, and the physical characteristics that did not affect the distribution of seagrass were currents and sea water transparency.

Estimating the change in regional scale distribution of seagrass and macroalgal beds using discrete local distribution data analyzed from aerial images

AbstractThe sensitivity of vegetated habitats to climate change and catastrophic disturbance, as well as their benefits to human beings, motivate efforts to estimate regional changes in distribution. This study examined the regional changes in the distribution of submerged macrophyte vegetation using aerial and satellite images from before and after the 2011 tsunami disturbance along the Pacific coast of northeastern Japan. We conducted an estimation of the change in the distribution of seagrass and macroalgal beds after the tsunami along the whole coastline (1,635 km). This was based on vegetation change in the 13 local areas (each &lt;40 km) spanning 27% of the coastline and included 28% of the macroalgal area and 59% of the seagrass area documented in satellite imagery before the tsunami, using generalized linear modeling (GLM). We found that in the 13 local areas 716.8 and 1,990.3 ha of macroalgal beds and seagrass beds had disappeared, respectively, suggesting that seagrass beds were more impacted by the tsunami than macroalgal beds. Significant predictors in GLM indicated that more seagrass beds disappeared in geographically complex coastal areas, whereas macroalgal beds were only marginally affected in such areas. It was estimated that the total decline in seagrass beds was at least 76% along the whole coastline, whereas macroalgal beds decreased only by about 20%. The magnitude and predictors of losses in these two vegetated habitats were similar to earlier estimates, suggesting that our simplified method with GLM is sufficient to extrapolate monitoring data to a regional scale.

Satellite image analysis reveals changes in seagrass beds at Van Phong Bay, Vietnam during the last 30 years

Seagrass meadows are fragile ecosystems in the coastal zone. Natural disasters, land reclamation and various human activities seem to exert negative impacts on the distribution and biological performance of seagrass beds in Vietnam. In this present study, satellite Landsat TM/OLI image analysis was applied to determine changes in seagrass distribution at Van Phong Bay, Vietnam in the last 30 years. The maximum likelihood decision rule was used to extract seagrass bed distribution data. The error matrix using the in situ reference data for HLM image classification was 81–95% accurate, and Kappa coefficients were between 0.72 and 0.91. The results indicated that 186.2 ha (or 35.8%) of the original seagrass beds were lost in the last three decades at Van Phong Bay, and decline in each specific site may have been due to different causes. Typhoons may have caused the loss of seagrass beds at open-sea sites whereas aquaculture activities, excavation and terrigenous obliteration may have caused such losses in protected sites.

Distribution and healthy status of seagrass bed in Lamongan coastal area

The important role of ecology and the high economic value of a seagrass beds are strongly influenced by its health status. The purposes of this study were to 1. analyze the distribution, extent and type of seagrass; 2. identify the seagrass covering and density; 3. analyze the health status of seagrass in the coastal village of Lamongan. This research was conducted in July to August 2019, along the coast of Lamongan Regency. Stages of research conducted include: tracking to determine the distribution and extent of seagrass beds, quadratic transects to determine seagrass covering and density, and analysis of seagrass health status. Lamongan consists of two coastal districts, namely: Paciran (9 coastal villages) and Brondong (9 coastal villages). Of the 18 coastal villages there are three coastal villages that have seagrass beds, namely: Banjarwati (7.7 Ha), Kranji (12 Ha), Tunggul (3.8 Ha), with the same type ofEnhalus acoroides, andThalassia hemprichiionly at Kranji village. Seagrass covering in the three villages were 83.7%, 15.1%, and 15.1%, while the density values were 160 stands/m2, 172 stands/m2, and 185 stands/m2. The seagrass beds in the study areas were classified as poor (&lt; 30%) to healthy (&gt; 60%).

Phân bố cỏ biển tại quần đảo Hải Tặc, thành phố Hà Tiên, tỉnh Kiên Giang

The study was conducted to assess the distribution of seagrass around Hai Tac archipelago, Ha Tien city, Kien Giang province. From two survey trips in September 2018 and March 2019, using the field survey methods of deep diving with SCUBA, photographing and sampling, the study has recorded 6 species of seagrass. These species were morphologically identified, namely: Cymodocea rotundata, Cymodocea serrulata, Halodule uninervis, Enhalus acoroides, Thalassia hemprichii, and Halophila ovalis. The seagrass beds occupied a surface area of approximately 30 hectares in Hai Tac archipelago. They mainly distributed in the Northeastern of Hon Doc, the East of Hon Truc Mon and the North of Hon Doi. In which, Thalassia hemprichii is always the most dominant species. In Hai Tac archipelago, the segrass’s shoots density was about 201 ± 34 shoots/m2; the average of coverage was 33.8 ± 15.1%; the average of biomass was 690 ± 267 g/m2; seagrass resource was estimated at 207 ± 80 tons. The research results are an important scientific basis for orienting the rational use of biodiversity and aquatic resources in the Southwestern of Vietnam.

Literature Synthesis for Assessment and Management of Seagrasses

This paper collates seagrass studies from 2008- 2017. The focus of review is on the studies conducted in Philippines and in some areas of world in relation to this dynamic and most productive marine ecosystem the seagrass meadows. The review reveals that there is an abundance in diversity, distribution and cover of seagrass in different parts of the country, wherein articles written in other part of the world provides data and information on physical, biological and economic importance of Seagrass in the human lives. The cause of its destruction was found out to be mostly anthropogenic activities. Limitations on the conducted studies in the Philippines was shown as reflected in the collected studies that are generally done along the coastal areas in the Visayas and Mindanao regions. Which practically shows an opportunity to explore different places in Luzon for an assessment of Seagrass for its ecosystem resiliency, stability, management and sustainability. Foreign studies included in the review reflects studies on assessment of biophysical characteristics of the seagrasses with the use of modern technologies like remote sensing and management practices that illustrates market value of ecosystem services of seagrass meadows on its application for some small-scale fisheries. Knowledge gap on socio-ecological importance of seagrasses, economic valuation of this marine habitat ecosystem services and wake up call for policy maker to consider seagrasses in their proposal for management shift of this ecologically significant habitat are topics needing further investigations.

The condition and composition of seagrass and mollusca on Biak island, Papua

This research was purposed to assess coverage and species distribution of seagrass as well as mollusca in Biak Island, Biak Numfor Regency, Papua. Field sampling was conducted in February, March and September 2017 at 18 observation stations. Eight seagrass species were recorded during the sampling period namely Thalassia hemprichii, Enhalus acoroides, Halodule uninervis, Halodule pinifolia, Syiringodium isoetifolium, Cymodocea rotundata, C. serrulata, and Halophila ovalis. The highest coverage was T. hemprichii, followed by C. rotundata and the least was C. serrulata. The range of seagrass coverage from 5.11% (St.1) to 75.76% (St.17) with the average of coverage in Biak was 35.7%. Furthermore, there were 4 groups based on Bray-Curtis similarity according to the seagrass assemblage in the research area. In addition, a total of 156 molluscan species were recorded consisted of 123 species from gastropod and 33 species from bivalvia. The most distributed species from gastropod were Conomurex luhuanus and Canarium urceus, while from bivalvia was Anadara antiquata. Station 15 has the highest species number with 33 species and the lowest, with just 9 species, were found at station 1 and 7.

SEAGRASS HABITAT SUITABILITY MAP AT MERAMBONG SHOAL, JOHOR: A PRELIMINARY STUDY USING MULTIBEAM ECHOSOUNDER AND MAXENT MODELLING

Abstract. In recent years, there has been an increasing interest to use high-resolution multibeam dataset and Species Distribution Modelling (SDM) for seagrass habitat suitability model. This requires a specific variable derived from multibeam data and in-situ seagrass occurrence samples. The purpose of this study was (1) to derive variables from multibeam bathymetry data to be used in seagrass habitat suitability model, (2) to produce seagrass habitat suitability model using Maximum Entropy (MaxEnt), and (3) to quantify the contribution of each variable for predicting seagrass habitat suitability map. The study area was located at Merambong Shoal, covering an area of 0.04 km2, situated along Johor Strait. First, twelve (12) variables were derived from bathymetry data collected from multibeam echosounder using Benthic Terrain Modeller (BTM) tool. Secondly, all variables and seagrass occurrence samples were integrated in MaxEnt to produce seagrass habitat suitability map. The results showed that the Area Under Curve (AUC) values based on training and test data were 0.88 and 0.65, respectively. The northwest region of survey area indicated higher habitat suitability of seagrass, while the southeast region of survey area indicated lower suitability. Bathymetry mean found to be the most contributed variables among others. The spatial distribution of seagrass from modelling technique agreed with the previous studies and they are found to be distributed at depths ranging from 2.2 to 3.4 meters whilst less suitable with increasing of water depth. This study concludes that seagrass habitat suitability map with high-resolution pixel size (0.5 meter) can be produced at Merambong Shoal using acoustic data from multibeam echosounder coupled with MaxEnt and underwater video observations.

Morphological plasticity in a Fijian Seagrass: Halophila ovalis subsp. bullosa

Seagrasses are marine flowering plants found along both tropical and temperate coastlines; they possess great ecological importance as nurseries, nutrient sinks, and providers of critical marine habitat. Understanding the distribution and diversity of seagrass habitats is important for their conservation and management, however this is impeded by varying species’ diversity, the extensive distribution of seagrasses and taxonomic uncertainty. In the Fiji Islands, the tropical seagrass Halophila ovalis and its subspecies H. ovalis bullosa are the subject of taxonomic controversy, as a singular morphological characteristic distinguishes the two. This characteristic is the bullated, or blister-like leaves of the latter, compared to the smooth leaves of the former, which in some instances have been observed on the same plant (S.S., pers. obs.). This study examined material from both taxa, along with three other seagrass species (Halodule pinifolia, H. uninervis and Syringodium isoetifolium; total n=95) and used independent morphological and molecular barcoding approaches to assess the conspecificity of the two Halophila taxa. Examination of vegetative and reproductive characters was not able to distinguish between H. ovalis and H. ovalis subsp. bullosa, while phylogenetic reconstructions using ITS2, matK and trnH-psbA barcodes supported their monophyly. We recommend revision and merger of these taxa, while the approach used here is highly useful for taxonomic resolution in other seagrass taxa, for their conservation, restoration and management.

Single beam sonar reveals the distribution of the eelgrass Zostera marina L. and threats from the green tide algae Chaetomorpha linum K. in Swan-Lake lagoon (China)

Seagrass meadows are declining at alarming rates globally due to both anthropogenic activities and natural threats. Seagrasses play key ecological roles in coastal ecosystems as primary producers and providers of habitat and environmental structure. Therefore, mapping seagrass beds is indispensable for the effective monitoring and management of coastal vegetated habitats. In contrast to direct sampling techniques and optical remote sensing, active hydroacoustic techniques are relatively inexpensive and efficient for the detection of seagrass. We used a single beam echosounder to detect the spatial and temporal distribution characteristics of the eelgrass Zostera marina L. in an important overwintering habitat for the whooper swan Cygnus cygnus (Swan-Lake lagoon), northern China. We also distinguished echograms of the macroalgae Chaetomorpha linum K. and outlined its threat to seagrass. We also propose a method for calculating the accuracy of interpolation analyses. Results showed that: (1) The distribution of seagrass in Swan Lake varies with seasons, with maximum distribution area in summer. The maximum distribution area of seagrass beds in Swan Lake was 199.09 ha–231.67 ha, accounting for 41.48%–48.26% of the area of Swan Lake; (2) C. linum is a growing threat for seagrass beds of Swan-lake, with distribution area as high as 129.28 ha in May 2018. The invasion and competition by C. linum against seagrass beds could be one of the reasons for the decline in seagrass beds in Swan-Lake; (3) Topo to Raster has the highest interpolation accuracy and is the most conservative among three interpolation methods. Topo to Raster was the most suitable interpolation method for the sonar detection of seagrass beds. The findings may facilitate the application of sonar technology in seagrass monitoring and provide data for the formulation of appropriate seagrass bed management and restoration strategies and policies.

Geomorphological and sedimentological surrogates for the understanding of seagrass distribution within a temperate nearshore setting (Esperance Western Australia)

Seagrass meadows are important benthic habitats contributing to many aspects of ecological community health, beach stability and sediment supply. Relationships between morpho-sedimentary features and distribution of seagrass meadows were investigated through an integrated analysis of geomorphology, sediments and benthic habitat structure in a temperate nearshore setting (Esperance Bay, Western Australia). The results demonstrate that seagrass distribution is related to gradients in sediment texture and composition, hydrodynamics and human impact. Dense seagrass meadows occurred in more sheltered regions of the bay, whereas sparser vegetation was found in areas of higher wave energy and artificial activities (like ship anchoring and dredging activities). A preferential retention of heavier siliciclastic sediments was recorded in the seagrass meadows especially in areas with high sediment supply resulting in elevated beds and formation of intermates. Sediment characteristics suggest that carbonate sediment is transported onshore from the seagrass meadow supplying the beach system. The combined analyses of geomorphological features and sediment characteristics at Esperance have allowed identification of a prevalent eastward oriented sediment transport current. Seagrass beds are confirmed to be a sediment source in terms of sediment budget contributing to beach stability. Integrated geomorphological data, sediment analyses and benthic habitat mapping provide useful information for the management of coastal environments characterized by the presence of seagrass meadows by providing new insights on coastal processes.

Influence of Water Temperature Anomalies on the Growth of Zostera marina Plants Held Under High and Low Irradiance Levels

Coastal water temperature anomalies are expected to intensify during the current period of global climate change. Sudden water temperature elevation (e.g., heat waves) or decrease (e.g., summer upwelling) can have a far-reaching influence on seagrasses in temperate regions. We examined the influence of anomalously elevated and decreased water temperatures on the growth of Zostera marina plants held under two different levels of irradiance. Core samples of wild Z. marina shoots were cultured under either suddenly elevated (from the in situ level of 20 to 27 °C during the fall experiment) or decreased (from the in situ level of 27 to 20 °C during the summer experiment) temperature. We included light as an experimental factor because the light requirements of seagrasses increase when plants are under thermal stress. The growth of Z. marina shoots under anomalously elevated water temperature conditions, which simulated marine heat waves, was significantly declined, whereas the plant growth under suddenly decreased water temperature conditions, which simulated summer upwelling events, was maintained or slightly increased. In the fall 2014 experimental period, Z. marina shoots under the suddenly elevated water temperature condition (27 °C) showed significant decreases in shoot density, biomass, and leaf productivity by ca. 40–80%, whereas plants held under the ambient water temperature condition (20 °C) maintained or slightly increased their growths. In the summer 2015 experimental period, Z. marina under the sudden temperature reduction conditions (20 °C) maintained relatively high shoot density and leaf productivity, whereas plants under the in situ high water temperature condition (27 °C) showed significantly reduced growths. The growth of Z. marina shoots, which were cultured in the optimal temperature condition (20 °C), was enhanced by increasing underwater irradiance. However, the adverse effects of high water temperature on Z. marina growth could not be reversed by increasing irradiance levels at the end of the experiments. According to the results of this study, the intensified sea surface water temperature anomalies induced by global climate change will alter the growth and distribution of temperate seagrasses and, consequently, the structure and function of the coastal seagrass ecosystems in the temperate region.

Species-specific distribution of intertidal seagrasses along environmental gradients in a tropical estuary (Brunei Bay, Borneo)

Seagrass diversity and distribution in Southeast Asia have been mainly studied in backreef zones but have rarely been studied on intertidal mudflats in estuaries. This research article aims to study seagrass distribution (species diversity, shoot density, and biomass) and morphology (leaf length and leaf number per shoot) on intertidal mudflats in Brunei Bay, Borneo, to understand seagrass responses to water and sediment conditions along the environmental gradient in the estuary. In total, five seagrass species (Cymodocea rotundata, Halodule pinifolia, Halophila ovalis, Halophila minor, and Thalassia hemprichii) were found at five different intertidal sites, and the diversity and biomass were highest at the most upstream site. H. pinifolia was the only species found at all five sites, indicating that this species is the most tolerant of and adaptable to varying water and sediment conditions. H. pinifolia had the highest biomass and longest leaf length at the site with the highest silt and clay percentage (SC%) and organic matter content of sediment, where no other seagrass species were found, suggesting that H. pinifolia could efficiently acquire nutrients without interspecies competition. In contrast, H. ovalis and T. hemprichii were found at the upstream sites and preferred a relatively low SC% in sediment. H. minor was found only at the most downstream site, which had the lowest SC% and is likely to experience the strongest hydrodynamics and receive the least nutrients of all the sites. Based on this study, the seagrass response to environmental gradients in estuaries is proposed to be species-specific, which would have led to the unique seagrass distribution in Brunei Bay.

Changes in hydrodynamics and wave energy as a result of seagrass decline along the shoreline of a microtidal back-barrier estuary

Seagrasses are marine flowering plants that provide key ecological services. In recent decades, multiple stressors have caused a worldwide decline in seagrass beds. Changes in bottom friction associated with seagrass loss are expected to influence the ability of estuarine systems to trap sediment inputs through local and regional changes in hydrodynamics. Herein, we document a numerical study using six historical maps of seagrass distribution in Barnegat Bay, USA, to demonstrate that reductions in seagrass coverage destabilize estuarine systems, decreasing flood-dominance in areas affected by seagrass disappearance and increasing bed-shear stress values across the entire back-barrier basin. Furthermore, we reveal how seagrass decline has considerably increased the impact of wind-waves on marsh edges between 1968 and 2009. From a comparison with a numerical experiment without submerged aquatic vegetation, we estimate that up to 40% of the computed wave thrust on marsh boundaries can be reduced by seagrass beds and we find that the location of a seagrass patch in addition to its aerial extent plays a crucial role in this attenuation process. This study highlights the benefits of seagrass meadows in enhancing estuarine resilience and reducing marsh-edge retreat by wind-wave attack, which is recognized as a chief agent in lateral marsh loss.

Seagrass Resource Assessment Using WorldView-2 Imagery in the Redfish Bay, Texas

Seagrass meadows play important roles as habitats for many marine organisms, traps for sediment, and buffers against wave actions. The objective of this paper is to map seagrass meadows in the Redfish Bay, Texas from WorldView-2 imagery. Seagrass meadows grow in shallow and clear water areas in the Redfish Bay. The WorldView-2 satellite can acquire multispectral imagery from the bay bottom with 2 m spatial resolution 8 multispectral bands and 0.46 m panchromatic imagery. The top of atmosphere radiance was transformed to the bottom reflectance through the atmospheric correction and the water column correction. The object based image analysis was used to identify seagrass meadows distributions in the Redfish Bay. This investigation demonstrated that seagrass can be identified with 94% accuracy, although seagrass species cannot be satisfactorily recognized. The results implied that the WorldView-2 satellite imagery is a suitable data source for seagrass distribution mapping.

An affordable and portable autonomous surface vehicle with obstacle avoidance for coastal ocean monitoring

Abstract Bathymetry measurements are needed in shallow, near-shore environments to estimate the potential distribution of macroalgae and seagrass, which contribute to oceanic carbon sinks in Greenland and other Arctic locations. Additionally, ocean current observations near icebergs and marine-terminating glaciers are necessary to estimate their melt rates. Rocky coastlines, icebergs and glaciers, however, present a significant safety risk to manned vessels. We developed an affordable and portable autonomous surface vehicle (ASV) that can safely obtain bathymetry and ocean current measurements in dangerous environments. The Arctic Research Centre Autonomous Boat (ARCAB) is a student-built ASV that can be transported on a euro-pallet and operated from a small boat and from shore. ARCAB has a minimum battery life of 2 h and accommodates a SonTek M9 RiverSurveyor system for bathymetry and ocean current measurements. ARCAB is controlled by a National Instruments myRIO-1900 and features autonomous waypoint navigation, obstacle avoidance, and return-to-home functionality. We demonstrate the use of ARCAB in Greenland in January 2019.

The spatial pattern of seagrass distribution and the correlation with salinity, sea surface temperature, and suspended materials in Banten Bay

Seagrass is a flowering plant (Angiospermae) that lives submerged in the water. The sustainability of seagrass meadow depends on oceanographic conditions on its habitats including salinity, sea surface temperature, and total suspended solids (TSS). In the Banten Bay, there has been a change in oceanographic condition by natural process and human activities. The change of oceanographic condition will have an impact on the seagrass growth. Remote sensing method can be used to determine the spatial distribution of seagrass and the oceanographic condition that consist of salinity, sea surface temperature, and suspended materials. Therefore, this purposes of this study were 1) mapping the spatial distribution of seagrass and oceanographic condition using Sentinel-2A and Landsat 8 OLI/TIRS imagery and 2) to explain the correlation between seagrass distribution and the salinity, temperature, and suspended materials distribution. The results of this study areseagrasses in Banten Bay were lives are in the salinity condition between 27‰ - 32‰, at the sea surface temperatures between 29°C-31°C, and at total suspended solids value between 19mg/l −30 mg/l.The sea surface temperature is the oceanographic parameters that have the highest correlation with seagrass, followed by total suspended solids and salinity.

Analysis of Seagrass Condition Using Spectral Reflection of Quickbird Imagery on Saronde Island North Gorontalo

This study was encouraged by the importance of understanding the conditions of seagrass which becomes the source of food for many species of marine fish. Seagrass condition will indirectly affect the quantity and quality of fish obtained by fishermen who live in coastal areas. High-resolution imagery can simplify and accelerate data collection process of conditions of seagrass on the outer islands of Gorontalo Province. This study used digital remote sensing method using unsupervised classification and also assisted by the measurements of the transcule based on the pixel size that aims to detect and to match the information obtained from QuickBird imagery, to ultimately obtain information about seagrass condition. Seagrass with abundant/good condition can be found at station 1,3,4,5, and 6 with an average cover up to 67,70%, 63,54%, 68,75%, 62,5%, and 65,62% respectively. Meanwhile, seagrass with the less abundant/poor condition can be found at station 2 with an average cover up to 50% and at station 7 with an average cover up to 52,08%. Distribution of seagrass on Saronde Island covers up to 6. 9654 Ha. Seagrass with abundant/good condition covers 4,2025 Ha, and lowly abundant/poor seagrass covers 2,7629 Ha. Seagrass on Saronde Island is still in abundant/good condition with an average cover up to 61,45 % and form mixed vegetation.

Seagrass meadow cover and species composition drive the abundance of Eurasian wigeon (Mareca penelope L.) in a lagoon ecosystem of the northern Adriatic Sea

A comprehensive understanding of the interactions between primary producers and consumers plays an important role for the conservation of sensitive ecosystems such as lagoons. In this light, we studied the relationships between the flocks' size of Mareca penelope and the distribution of three seagrass species (Cymodocea nodosa, Zoostera marina and Nanozostera noltei) occurring in the Marano and Grado lagoon (Northern Adriatic Sea). Twelve bird monitoring areas were monthly surveyed for 3 years whereas seagrass distribution data were collected for the whole lagoon in the following years. The overall number of individuals of M. penelope was related to seagrass meadow extension and species cover by using a multiscale approach in four circle buffers (with radius of 500, 750, 1,000 and 1,250 m). Among the considered scales, the 750 m radius scale showed the best performance. The overall number of M. penelope increased where the occupied area by seagrass meadows was larger. Results also showed that when C. nodosa mean percentage cover increased the number of M. penelope decreased, while if N. noltei mean percentage cover increased also M. penelope number increased. Z. marina showed a negligible influence for all the tested scales. Our findings demonstrate that M. penelope populations depend not only on the extension of seagrass meadows but also on their species assembly, evidencing that M. penelope seem to prefer N. noltei stands, avoiding meadows with high abundance of C. nodosa.