scholarly journals Seasonal Patterns of Sporophyte Growth, Fertility, Fouling, and Mortality ofSaccharina latissimain Skagerrak, Norway: Implications for Forest Recovery

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Guri Sogn Andersen ◽  
Henning Steen ◽  
Hartvig Christie ◽  
Stein Fredriksen ◽  
Frithjof Emil Moy
Keyword(s):  
Seasonal Variations ◽  
Life Stage ◽  
Kelp Forest ◽  
Forest Recovery ◽  
Saccharina Latissima ◽  
Seasonal Patterns ◽  
Study Sites

On the Skagerrak coast the kelpSaccharina latissimahas suffered severe stand reductions over the last decade, resulting in loss of important habitats. In the present study, healthy kelp plants were transplanted into four deforested areas and their patterns of growth, reproduction, and survival were monitored through subsequent seasons. Our main objective was to establish whether the kelp plants were able to grow and mature in deforested areas. We observed normal patterns of growth and maturation at all study sites. However, heavy fouling by epiphytes occurred each summer, followed by high kelp mortality. The study shows that the seasonal variations and the life stage timing ofS. latissimamake formation of self-sustainable populations impossible in the present environment. Most noteworthy, we suggest that fouling by epiphytes is involved in the lack of kelp forest recovery in Skagerrak, Norway.

Mechanisms leading to recruitment inhibition of giant kelp Macrocystis pyrifera by an understory alga

2021 ◽  
Vol 657 ◽  
pp. 59-71
Author(s):  
BA Beckley ◽  
MS Edwards
Keyword(s):  
Field Experiments ◽  
Local Community ◽  
Kelp Forest ◽  
Macrocystis Pyrifera ◽  
Forest Recovery ◽  
Kelp Forests ◽  
Giant Kelp ◽  
Combined Effects ◽  
Life Stages ◽  
Survival And Growth

The forest-forming giant kelp Macrocystis pyrifera and the communities it supports have been decreasing across their native ranges in many parts of the world. The sudden removal of giant kelp canopies by storms increases space and light for the colonization by understory macroalgae, such as Desmarestia herbacea, which can inhibit M. pyrifera recovery and alter local community composition. Understanding the mechanisms by which algae such as D. herbacea interact with M. pyrifera can provide insight into patterns of kelp forest recovery following these disturbances and can aid in predicting future community structure. This study experimentally tested the independent and combined effects of two likely competitive mechanisms by which D. herbacea might inhibit recovery of M. pyrifera in the Point Loma kelp forest in San Diego, California (USA). Specifically, we conducted field experiments to study the individual and combined effects of shade and scour by D. herbacea on the survival of M. pyrifera microscopic life stages, and the recruitment, survival, and growth of its young sporophytes. Our results show that scour had the strongest negative effect on the survival of M. pyrifera microscopic life stages and recruitment, but shade and scour both adversely affected survival and growth of these sporophytes as they grew larger. Canopy-removing storms are increasing in frequency and intensity, and this change could facilitate the rise of understory species, like D. herbacea, which might alter community succession and recovery of kelp forests.

Seagrass surveys in Shwe Thaung Yan coastal areas, the southern part of Rakhine Coastal Region, Myanmar: biodiversity, coverage and biomass

2019 ◽  
Vol 8 (3) ◽  
pp. 105-112
Author(s):  
Thu- Rein
Keyword(s):  
Seasonal Variations ◽  
Seagrass Meadow ◽  
Monsoon Season ◽  
Coastal Region ◽  
Coastal Areas ◽  
Dry Season ◽  
Percent Cover ◽  
Study Sites ◽  
Seagrass Coverage

Studies on percent cover and biomass of seagrasses from Shwe Thaung Yan coastal areas (Inn Din Gyi, Kyauk Nagar and Phoe Htaung Gyaing), the Southern parts of Rakhine Coastal Region, were carried out between March and August, 2018. A total of 8 species of seagrasses, namely Syringodiumisoetifolium (Ascherson) Danty, Halodulepinifolia (Miki) den Hartog, Haloduleuninervis (Forsskal) Ascherson, Cymodocearotundata Ehrenberg et Hemprich ex Ascherson, C. serrulata (R. Brown) Ascherson et Magnus, Thalassiahemprichii(Ehrenberg) Ascherson, Halophila major (Zoll.) Miquel and Enhalusacoroides (Linnaeus f.) Royle, were recorded in three study sites. Seagrass meadow in this study showed seasonal variations in both percent cover and biomass. Total seagrass coverage and biomass were higher in the dry season than in the monsoon season. Total seagrass coverage ranged between 8% and 75% in Phoe Htaung Gyaing, between 10% and 42% in Kyauk Nagar, and between 15% and 43% in Inn Din Gyi. Total seagrass mean biomass was 50.2413-259.846gdry.wtm-2 in Phoe Htaung Gyaing, 63.0194 -321.535gdry.wtm-2 in Kyauk Nagar, and 98.6819-416.237gdry.wtm-2 in Inn Din Gyi.

scholarly journals ESTUDIO DEMOGRÁFICO DE Emilia sonchifolia (ASTERACEAE) EN UNA FINCA CAFETERA DE ARMENIA, QUINDÍO, COLOMBIA

2014 ◽  
Vol 20 (2) ◽  
Author(s):  
Irene Duarte Gandica ◽  
Maryam Chaib de Mares ◽  
David Andrés Luna ◽  
Oscar Alexander Aguirre-Obando ◽  
Rosa María Méndez Parra
Keyword(s):  
Logistic Model ◽  
Research Study ◽  
Life Stage ◽  
Coffee Plantation ◽  
Simulation Based ◽  
Coffee Farm ◽  
Number Of Leaves ◽  
Potential Strategy ◽  
Study Sites ◽  
Number Of Individuals

<p>Se realizó un estudio con el fin de determinar la estructura demográfica de <em>Emilia sonchifolia </em>(L.) DC<em> </em>en una finca cafetera del Municipio de Armenia, Quindío, Colombia, donde se recolectaron datos durante 4 semanas, en tres sitios: exterior, borde e interior del cultivo. Usando parámetros calculados a partir de los datos de campo, se construyó un modelo logístico para describir el comportamiento poblacional en el tiempo. Se encontraron diferencias significativas en las variables: número de individuos por estado etario en el tiempo, porcentaje de mortalidad, tiempo de cambio del estado plántula a juvenil y de juvenil a adulto, número de hojas y de ramas; no se encontraron diferencias significativas en la densidad poblacional, número de inflorescencias e infrutescencias en los sitios de estudio. En general, se puede atribuir este comportamiento a la estrategia de reproducción <em>r</em> que sigue <em>E. sonchifolia</em>. Finalmente, las simulaciones hechas a partir del modelo logístico sugieren que la especie tiende a desaparecer si alguno de los estados etarios no está presente inicialmente; así, una alternativa plausible para el control sería su eliminación en el estado juvenil. Los resultados ofrecen alternativas con respecto al manejo de<em> </em>poblaciones de arvenses.</p><p><strong>ABSTRACT</strong></p><p>A research study was conducted to determine the demographic structure of <em>Emilia sonchifolia</em> L. in a coffee plantation in Armenia, Quindío, Colombia. Data were collected over a period of four weeks on three sites: inside, at the border and outside a coffee farm. A logistic population model was built to describe the population behavior of <em>E. sonchifol</em><em>ia </em>over time. Statiscally significant differences were found between: number of individuals per life stage in time, mortality rate, transition time from seedling to juvenile and from juvenile to adult; and number of leaves and branches. There was no evidence for statistically significant differences in population density or in number of inflorescences and fruits between study sites. In general, the observed behavior may be attributed to the <em>r</em> strategy used by this species. Finally, our results suggest the survival of the species is conditioned by the presence of all life stages at the beginning of each simulation based on the logistic model; so, a potential strategy for its controlling would require the removal during the juvenile stage. The considerations offer alternatives regarding weed population management.  </p>

scholarly journals Spatial and Seasonal Variations of Standardized Photosynthetic Parameters under Different Environmental Conditions for Young Planted Larix olgensis Henry Trees

Forests ◽  
2018 ◽  
Vol 9 (9) ◽  
pp. 522 ◽  
Author(s):  
Qiang Liu ◽  
Fengri Li
Keyword(s):  
Environmental Conditions ◽  
Seasonal Variations ◽  
Seasonal Pattern ◽  
Repeated Measurements ◽  
Seasonal Patterns ◽  
Photosynthetic Parameters ◽  
Relative Depth ◽  
Larix Olgensis ◽  
Vertical Variations ◽  
Larix Olgensis Henry

Understanding the spatial and seasonal variations in leaf physiology is critical for accurately modeling the carbon uptake, physiological processes and growth of entire canopies and stands. For a 17-year-old Larix olgensis Henry plantation, vertical whorl-by-whorl sampling and analyses of seasonally repeated measurements of major photosynthetic parameters were conducted, and the correlations between photosynthetic parameters and environmental conditions, leaf morphological traits and spatial position within the crown were analyzed. According to the correlations, the photosynthetic parameters were standardized based on the environmental conditions to avoid the influence of the changing environment on the patterns of spatial and seasonal variations of photosynthetic parameters. The results showed that the standardized light-saturated net photosynthetic rate (SPmax), standardized dark respiration (SRd) and standardized stomatal conductance under saturated light (Sgs-sat) were all negatively related to the relative depth into the crown (RDINC) throughout the growing season. However, their vertical patterns were different during the development of the phenological phase. In addition, different gradients of environmental conditions also influenced the values and the range of the vertical variation in photosynthesis. High temperature and low humidity usually resulted in smaller values and weaker vertical variations of SPmax and Sgs-sat, but larger values and more obvious vertical variations in SRd. SPmax and Sgs-sat usually exhibited a parabolic seasonal pattern in different vertical positions within the crown; however, SRd generally followed a concave pattern. These seasonal patterns were all weaker with increasing RDINC. Different environments also exhibited a significant influence on the seasonal patterns of photosynthesis. We suggested that standardization is necessary before analyzing spatial and seasonal variations. A single environmental condition could not represent the spatial and seasonal patterns under all gradients of the environment. Spatial and seasonal variations should be simultaneously analyzed because they are related to each other.

Seasonal variations in intertidal density of invertebrate prey in a tropical lagoon and effects of shorebird predation

1994 ◽  
Vol 72 (10) ◽  
pp. 1755-1763 ◽  
Author(s):  
Francine Mercier ◽  
Raymond McNeil
Keyword(s):  
Seasonal Variations ◽  
Census Data ◽  
Invertebrate Prey ◽  
Exclosure Experiment ◽  
Tropical Environments ◽  
Energy Demands ◽  
Study Sites ◽  
Intertidal Surface ◽  
The Impact ◽  
Prey Depletion

We analyzed the relationship between the abundance of shorebirds and that of their intertidal invertebrate prey, and attempted to determine if shorebird predation significantly affects prey density. The study was conducted at three sites in the Chacopata Lagoon complex in northeastern Venezuela between January 1985 and September 1986, using shorebird census data, monthly sampling of intertidal invertebrates, and exclosure experiments. The invertebrates collected were divided into three groups: (i) polychaetes (≤50 mm in length), (ii) small bivalves (2 – 3 mm in length), and (iii) other species. The overall density of shorebirds foraging in the Chacopata Lagoon complex was very high, exceeding the densities reported for most other staging and overwintering areas by a wide margin. The abundance of shorebirds in the study area was related primarily to the density of polychaetes, their main prey. At two of the study sites, the arrival of fall migrants followed a significant increase in polychaete numbers. The increase in shorebird numbers in autumn was negligible at the third site, where polychaete density was lower than at the other sites. The impact of shorebird predation on their invertebrate prey varied seasonally, as did the extent of the foraging area available to them. The exclosure experiment revealed significant differences in the density of polychaetes inside and outside the exclosures only during, or shortly after, the fall migration period. The variability in the conclusions drawn from other studies examining prey depletion by shorebirds in tropical environments may be explained by differences in the length of sampling periods and seasonal variations in the numbers of foraging shorebirds, the energy demands of moult, fat deposition, and the intertidal surface area available for feeding. The impact of seasonal variables such as these should be taken into consideration when designing studies to measure prey depletion by shorebirds; such objectives may necessitate long-term studies.

scholarly journals Lack of sea urchin settlement may explain kelp forest recovery in overgrazed areas in Norway

2013 ◽  
Vol 488 ◽  
pp. 119-132 ◽  
Author(s):  
CW Fagerli ◽  
KM Norderhaug ◽  
HC Christie
Keyword(s):  
Sea Urchin ◽  
Kelp Forest ◽  
Forest Recovery

scholarly journals Habitat utilisation by Cape mountain zebras in the Mountain Zebra National Park, South Africa

Koedoe ◽  
1995 ◽  
Vol 38 (1) ◽  
Author(s):  
A. Winkler ◽  
N. Owen-Smith
Keyword(s):  
South Africa ◽  
Seasonal Variations ◽  
Seasonal Cycle ◽  
National Park ◽  
Annual Rainfall ◽  
Seasonal Patterns ◽  
Wet Season ◽  
Vegetation Community ◽  
Grassland Vegetation ◽  
Vegetation Communities

This study investigated the seasonal patterns of vegetation community use by the Cape mountain zebra within the Mountain Zebra National Park over one seasonal cycle. Day-time censuses revealed that the zebras utilised all the different vegetation commu- nities that were defined in the park, with the exception of the riparian bush community. Year-round the zebras made greatest use of the grassland vegetation communities, together with those shrubland and dwarf shrubland communities that offered high grass biomasses. Selectivity for vegetation communities was greatest during the wet season, when the zebras favoured those grassland communities on the plateaus over other vegetation communities on the mountain slopes and in the ravines. During the dry season the zebras showed a greater diversity in their use of vegetation communities, and made greater use of those vegetation communities on the mountain slopes and in the ravines. The results suggest that the seasonal variations in vegetation community use by the zebras were in response to changes in the annual rainfall pattern.

scholarly journals Monitoring of temporal trend of atmospheric metals by moss Hypnum cupressiforme Hedw in Jammu (India)

2020 ◽  
Vol 17 (02) ◽  
Keyword(s):  
Seasonal Variations ◽  
Cost Effective ◽  
Atmospheric Pollutants ◽  
Percentage Increase ◽  
Jammu And Kashmir ◽  
Moss Species ◽  
Average Percentage ◽  
Hypnum Cupressiforme ◽  
Metal Load ◽  
Study Sites

Atmospheric pollutants, such as metals, are extremely variable in space and time and it is cumbersome and expensive to deduce detailed information over a vast area using traditional instruments. Consequently, a cost-effective bio-monitor was preferred in the present study to analyze the atmospheric metal load. For this purpose, a moss Hypnum cupressiforme Hedw was inducted amongst moss species available to evaluate the intensity and trend of atmospheric deposition of Zn, Cu, Cd, and Pb in Jammu in the state of Jammu and Kashmir, India for a period of three years, 2014- 2016. The biomonitoring experimentation was performed by transplanting moss bags prepared from Hypnum cupressiforme, after validating its tolerance against metals using a photosynthetic efficiency analyzer in the field. Moss Hypnum cupressiforme Hedw exposed seasonally, covering summer, monsoon, and winter periods, upon the analysis provided time-integrated patterns of metal bioavailability at the study sites. An attempt was made to compare the seasonal variations during the three years of study and findings exhibited significant seasonal variations in metal. The gradient of the metal load was in the order of Cu>Cd>Zn>Pb. The total average percentage increase in the metals under consideration, Zn, Pb, Cu, and Cd, was 40%, 37%,79%, and 76%, respectively during three subsequent years. It is worth mentioning here that biomonitoring studies on atmospheric metals have never been explored for this region.

scholarly journals Deep longitudinal multiomics profiling reveals two biological seasonal patterns in California

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
M. Reza Sailani ◽  
Ahmed A. Metwally ◽  
Wenyu Zhou ◽  
Sophia Miryam Schüssler-Fiorenza Rose ◽  
Sara Ahadi ◽  
...  
Keyword(s):  
Seasonal Variations ◽  
Cardiovascular Health ◽  
Molecular Data ◽  
Seasonal Patterns ◽  
Biological Processes ◽  
Early Winter ◽  
Insulin Resistant ◽  
Psychiatric Conditions ◽  
Clinical Measures ◽  
Calendar Dates

Abstract The influence of seasons on biological processes is poorly understood. In order to identify biological seasonal patterns based on diverse molecular data, rather than calendar dates, we performed a deep longitudinal multiomics profiling of 105 individuals over 4 years. Here, we report more than 1000 seasonal variations in omics analytes and clinical measures. The different molecules group into two major seasonal patterns which correlate with peaks in late spring and late fall/early winter in California. The two patterns are enriched for molecules involved in human biological processes such as inflammation, immunity, cardiovascular health, as well as neurological and psychiatric conditions. Lastly, we identify molecules and microbes that demonstrate different seasonal patterns in insulin sensitive and insulin resistant individuals. The results of our study have important implications in healthcare and highlight the value of considering seasonality when assessing population wide health risk and management.

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