scholarly journals Is the impact of eutrophication on phytoplankton diversity dependent on lake volume/ecosystem size?

2016 ◽  
Author(s):  
Didier L. Baho ◽  
Stina Drakare ◽  
Richard K. Johnson ◽  
Craig R. Allen ◽  
David G. Angeler
Keyword(s):  
Species Diversity ◽  
Growing Season ◽  
Phytoplankton Diversity ◽  
Habitat Features ◽  
Anthropogenic Stressors ◽  
Lake Volume ◽  
Ecosystem Size ◽  
Phytoplankton Communities ◽  
The Impact ◽  
Local Habitat

<p>Research focusing on biodiversity responses to the interactions of ecosystem size and anthropogenic stressors are based mainly on correlative gradient studies, and may therefore confound size-stress relationships due to spatial context and differences in local habitat features across ecosystems. We investigated how local factors related to anthropogenic stressors (<em>e.g.,</em> eutrophication) interact with ecosystem size to influence species diversity. In this study, constructed lake mesocosms (with two contrasting volumes: 1020 (shallow mesocosms) and 2150 (deep mesocosms) litres) were used to simulate ecosystems of different size and manipulated nutrient levels to simulate mesotrophic and hypertrophic conditions. Using a factorial design, we assessed how the interaction between ecosystem size and nutrients influences phytoplankton diversity. We assessed community metrics (richness, diversity, evenness and total biovolumes) and multivariate community structure over a growing season (May to early November 2011). Different community structures were found between deep and shallow mescosoms with nutrient enrichment: Cyanobacteria dominated in the deep and Charophyta in the shallow mesocosms. In contrast, phytoplankton communities were more similar to each other in the low nutrient treatments; only Chlorophyta had generally a higher biovolume in the shallow compared to the deep mesocosms. These results suggest that ecosystem size is not only a determinant of species diversity, but that it can mediate the influence of anthropogenic effects on biodiversity. Such interactions increase the uncertainty of global change outcomes, and should therefore not be ignored in risk/impact assessment and management.</p>

scholarly journals The state of hydrobionts in the Tyub‐Karagan Bay structure, Kazakhstan

2021 ◽  
Vol 16 (1) ◽  
pp. 138-150
Author(s):  
A. Kenzhegaliev ◽  
A. Sh. Kanbetov ◽  
A. A. Abilgazieva ◽  
A. К. Sakhmanova ◽  
D К. Kulbatyrov 
Keyword(s):  
Species Richness ◽  
Species Diversity ◽  
Species Composition ◽  
Seasonal Dynamics ◽  
Growing Season ◽  
The State ◽  
Average Weight ◽  
Research Station ◽  
Phytoplankton Communities ◽  
Quantitative Indicators

Aim. The purpose of the research was to study the state of hydrobionts in the Tyub‐Karagan Bay structure by season for a comparative analysis of their state with previous studies by the authors.Material and Methods. The conditions of hydrobionts (phyto, zoo‐plankton and macrozoobenthos) of the Tyub‐Karagan Bay structure have been studied for three seasons. Studies were carried out by traditional methodology.Results. The species composition of phytoplankton communities in spring was found to be less constant than in autumn; this is associated with heterogeneity in external conditions at the beginning of the growing season. The seasonal dynamics of zooplankton conformed to certain patterns. As a rule, from the beginning to the end of the growing season there was an enrichment of species composition and an increase in the quantitative indicators of zooplankton communities. The highest biomass was formed by bottom cenoses, where large mollusks play a leading role.Conclusion. During the 2018 research period, species richness and species diversity of phytoplankton were at a high level. Representatives of two categories were observed most often. Blue‐green dominated in number, while diatoms formed the basis of biomass. Species richness and species diversity of zooplankton was at a low or moderate level and most often constant. The seasonal dynamics of macrozoobenthos had common and specific features, depending on the research station location. Disproportionate changes in the quantitative indicators of bentonites are associated with a decrease in the average weight of individuals by autumn. This happened both through the strengthening of the role of small species and by an increase in the proportion of younger age stages in populations of bottom invertebrates.

scholarly journals Phytoplankton diversity in relation to different weather conditions in two urban made lakes

2016 ◽  
Vol 4 (1) ◽  
Author(s):  
Munay Abdulqadir Omar ◽  
Mohamed Amar Naqqiuddin ◽  
Shamarina Shohaimi ◽  
Hishamuddin Omar ◽  
Ahmad Ismail
Keyword(s):  
Global Warming ◽  
Dominant Species ◽  
Diversity Index ◽  
Weather Conditions ◽  
Engineering Faculty ◽  
Phytoplankton Diversity ◽  
Phytoplankton Communities ◽  
Rain Fall ◽  
Weather Changes ◽  
The Impact

ABSTRACTMany scientists have reported that global warming have significant impact on phytoplankton community, however, the impact of global warming on phytoplankton communities in suburban made lake is less understood. Therefor the objective of this study are to observe the effect of variable weather conditions on the diversity and succession of phytoplankton in mesotrophic lake (Seri Serdang) and oligotrophic lake (Engineering Faculty Lake). Samples were collected from surface water and species diversity (Shannon Weaver Diversity Index) was calculated. Daily weather and rain fall were recorded. A total of 65 species from five divisions (Chlorophyta, Euglenophyta, Cyanophyta, Bacillariophyta and Dinophyta) and 52 species belonging to six divisions (Chlorophyta, Cyanophyta, Bacillariophyta, Euglenophyta, Cryptophyta & Charophyta) were recorded from Engineering Faculty Lake and Seri Serdang Lake respectively. Division of Chlorophyta was found most dominant in both lakes during all the weeks (67%). The most dominant species in Faculty Engineering Lake was Microcystis aeruginosa during all weather conditions. Whereas, the most dominant species in Seri Serdang Lake during all weather conditions were Chlamydomonas reinhardtii, Planktothrix agardhii. The phytoplankton density was low during dry weather conditions for both lakes. The present finding suggested noticeable correlation between weather changes to the alteration of population density of phytoplankton. 

Understory use by terrestrial small mammals in an unflooded forest patch in the Pantanal floodplain

Mammalia ◽  
2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Nayara Yoshie Sano ◽  
Heitor Miraglia Herrera ◽  
Grasiela Edith de Oliveira Porfirio ◽  
Filipe Martins Santos
Keyword(s):  
Small Mammals ◽  
Small Mammal ◽  
Understory Vegetation ◽  
Monodelphis Domestica ◽  
Forest Patch ◽  
Habitat Features ◽  
Species Characteristics ◽  
Local Habitat

AbstractTo date, there have been no studies that have evaluated small mammal utilization of the understory of forests. In this study, we described the use of vertical strata by small mammals in patches of unflooded forests, known as “cordilheiras”, in the Nhecolândia sub-region of the Pantanal, Brazil. We collected all species using the ground and understory, including the terrestrial didelphid Monodelphis domestica. We suppose that local habitat features (e.g., Acuri palms), rather than intrinsic species characteristics, may be more conducive to the use of understory vegetation by small mammals in the Nhecolândia region.

scholarly journals The Impact of Climate Change on the Sugar Content of Grapes and the Sustainability of their Production in the Czech Republic

2020 ◽  
Vol 13 (1) ◽  
pp. 222
Author(s):  
Miroslava Navrátilová ◽  
Markéta Beranová ◽  
Lucie Severová ◽  
Karel Šrédl ◽  
Roman Svoboda ◽  
...  
Keyword(s):  
Climate Change ◽  
Czech Republic ◽  
Sugar Content ◽  
Growing Season ◽  
Vegetation Period ◽  
The Czech Republic ◽  
Impact Of Climate Change ◽  
Secondary Sources ◽  
The Impact ◽  
Growing Region

The aim of the presented article is to evaluate the impact of climate change on the sugar content of grapes in the Czech Republic during the period 2000–2019 through selected indicators on the basis of available secondary sources. Attention is focused on the developments in both the main wine-growing regions of Moravia and Bohemia. In the field of viticulture and wine-growing, the sugar content of grapes, as a basic parameter for the classification of wines, plays an important role. In the Czech Republic, the average sugar content of grapes has had a constantly growing trend. This trend is evident both in the wine-growing region of Bohemia and in the wine-growing region of Moravia. The impact of climate change, especially the gradual increase of average temperatures in the growing season, cannot be overlooked. It greatly affects, among other things, the sugar content of grapes. Calculations according to the Huglin Index and the Winkler Index were used to determine the relationship between climate and sugar content. These indexes summarize the course of temperatures during the entire vegetation period into a single numerical value. The results show that both indexes describe the effect of air temperature on sugar content in both wine regions of the Czech Republic in a statistically significant way. The Huglin Index shows a higher correlation rate. The Winkler Index proved to be less suitable for both areas. Alternatively, the Winkler Index calculated for a shorter growing season was tested, which showed a higher degree of correlation with sugar content, approaching the significance of the Huglin Index.

scholarly journals Vegetation Dynamic Assessment by NDVI and Field Observations for Sustainability of China’s Wulagai River Basin

2021 ◽  
Vol 18 (5) ◽  
pp. 2528
Author(s):  
Panpan Chen ◽  
Huamin Liu ◽  
Zongming Wang ◽  
Dehua Mao ◽  
Cunzhu Liang ◽  
...  
Keyword(s):  
Species Diversity ◽  
River Basin ◽  
Vegetation Change ◽  
Vegetation Index ◽  
Dynamic Assessment ◽  
Indicator System ◽  
Vegetation Changes ◽  
Vegetation Dynamic ◽  
Management Policies ◽  
The Impact

Accurate monitoring of grassland vegetation dynamics is essential for ecosystem restoration and the implementation of integrated management policies. A lack of information on vegetation changes in the Wulagai River Basin restricts regional development. Therefore, in this study, we integrated remote sensing, meteorological, and field plant community survey data in order to characterize vegetation and ecosystem changes from 1997 to 2018. The residual trend (RESTREND) method was utilized to detect vegetation changes caused by human factors, as well as to evaluate the impact of the management of pastures. Our results reveal that the normalized difference vegetation index (NDVI) of each examined ecosystem type showed an increasing trend, in which anthropogenic impact was the primary driving force of vegetation change. Our field survey confirmed that the meadow steppe ecosystem increased in species diversity and aboveground biomass; however, the typical steppe and riparian wet meadow ecosystems experienced species diversity and biomass degradation, therefore suggesting that an increase in NDVI may not directly reflect ecosystem improvement. Selecting an optimal indicator or indicator system is necessary in order to formulate reasonable grassland management policies for increasing the sustainability of grassland ecosystems.

scholarly journals Facilitation Effects of Haloxylon salicornicum Shrubs on Associated Understory Annuals, and a Modified “Stress-Gradient” Hypothesis for Droughty Times

Plants ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1726
Author(s):  
Nasr H. Gomaa ◽  
Ahmad K. Hegazy ◽  
Arafat Abdel Hamed Abdel Latef
Keyword(s):  
Species Richness ◽  
Water Availability ◽  
Stress Gradient ◽  
Growing Season ◽  
Annual Species ◽  
Negative Effects ◽  
Growing Seasons ◽  
Dry Seasons ◽  
The Impact ◽  
Haloxylon Salicornicum

Perennial shrub-annual plant interactions play key roles in desert regions influencing the structure and dynamics of plant communities there. In the present study, carried out in northwestern Saudi Arabia, we examined the effect of Haloxylon salicornicum shrubs on their associated understory annual species across four consecutive growing seasons, along with a record of the seasonal rainfall patterns. We measured density and species richness of all the annual species in permanent quadrats located beneath individual shrubs, as well as in the spaces between shrubs. During wet growing season H. salicornicum shrubs significantly enhanced the density and species richness of sub-canopy species, whereas in the relatively dry seasons they exerted negative effects on the associated species. In all growing seasons, the presence of shrubs was associated with enhanced soil properties, including increased organic carbon content, silt + clay, and levels of nutrients (N, P and K). Shrubs improved soil moisture content beneath their canopies in the wet growing season, while in the dry seasons they had negative effects on water availability. Differences in effects of H. salicornicum on understory plants between growing seasons seem due to the temporal changes in the impact of shrubs on water availability. Our results suggest the facilitative effects of shrubs on sub-canopy annuals in arid ecosystems may switch to negative effects with increasing drought stress. We discuss the study in light of recent refinements of the well-known “stress-gradient hypothesis”.

scholarly journals Modeling the Impact of Climate Changes on Crop Yield: Irrigated vs. Non-Irrigated Zones in Mississippi

2021 ◽  
Vol 13 (12) ◽  
pp. 2249
Author(s):  
Sadia Alam Shammi ◽  
Qingmin Meng
Keyword(s):  
Climate Change ◽  
Crop Yield ◽  
Crop Yields ◽  
Negative Impact ◽  
Positive Impact ◽  
Information Criterion ◽  
Growing Season ◽  
Maximum Temperature ◽  
Linear Regression Models ◽  
The Impact

Climate change and its impact on agriculture are challenging issues regarding food production and food security. Many researchers have been trying to show the direct and indirect impacts of climate change on agriculture using different methods. In this study, we used linear regression models to assess the impact of climate on crop yield spatially and temporally by managing irrigated and non-irrigated crop fields. The climate data used in this study are Tmax (maximum temperature), Tmean (mean temperature), Tmin (minimum temperature), precipitation, and soybean annual yields, at county scale for Mississippi, USA, from 1980 to 2019. We fit a series of linear models that were evaluated based on statistical measurements of adjusted R-square, Akaike Information Criterion (AIC), and Bayesian Information Criterion (BIC). According to the statistical model evaluation, the 1980–1992 model Y[Tmax,Tmin,Precipitation]92i (BIC = 120.2) for irrigated zones and the 1993–2002 model Y[Tmax,Tmean,Precipitation]02ni (BIC = 1128.9) for non-irrigated zones showed the best fit for the 10-year period of climatic impacts on crop yields. These models showed about 2 to 7% significant negative impact of Tmax increase on the crop yield for irrigated and non-irrigated regions. Besides, the models for different agricultural districts also explained the changes of Tmax, Tmean, Tmin, and precipitation in the irrigated (adjusted R-square: 13–28%) and non-irrigated zones (adjusted R-square: 8–73%). About 2–10% negative impact of Tmax was estimated across different agricultural districts, whereas about −2 to +17% impacts of precipitation were observed for different districts. The modeling of 40-year periods of the whole state of Mississippi estimated a negative impact of Tmax (about 2.7 to 8.34%) but a positive impact of Tmean (+8.9%) on crop yield during the crop growing season, for both irrigated and non-irrigated regions. Overall, we assessed that crop yields were negatively affected (about 2–8%) by the increase of Tmax during the growing season, for both irrigated and non-irrigated zones. Both positive and negative impacts on crop yields were observed for the increases of Tmean, Tmin, and precipitation, respectively, for irrigated and non-irrigated zones. This study showed the pattern and extent of Tmax, Tmean, Tmin, and precipitation and their impacts on soybean yield at local and regional scales. The methods and the models proposed in this study could be helpful to quantify the climate change impacts on crop yields by considering irrigation conditions for different regions and periods.

scholarly journals The impact of spatial isolation and local habitat conditions on colonization of recent forest stands by ectomycorrhizal fungi

2018 ◽  
Vol 429 ◽  
pp. 84-92 ◽  
Author(s):  
Margaux Boeraeve ◽  
Olivier Honnay ◽  
Nele Mullens ◽  
Kris Vandekerkhove ◽  
Luc De Keersmaeker ◽  
...  
Keyword(s):  
Ectomycorrhizal Fungi ◽  
Habitat Conditions ◽  
Forest Stands ◽  
Spatial Isolation ◽  
The Impact ◽  
Local Habitat

Can management improve the lawn’s functioning in the conditions of multiple anthropogenic stressors?

2021 ◽  
Author(s):  
Olga Gavrichkova ◽  
Dario Liberati ◽  
Viktoriya Varyushkina ◽  
Kristina Ivashchenko ◽  
Paolo De Angelis ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Soil Respiration ◽  
Green Infrastructure ◽  
Urban Areas ◽  
Ecosystem Respiration ◽  
Heterotrophic Respiration ◽  
Sand Mixture ◽  
Anthropogenic Stressors ◽  
Unplanted Soil ◽  
The Impact

&lt;p&gt;Release of heavy metals, salts and other toxic agents in the environment is of increasing concern in urban areas. Contaminants not solely decline the quality of the local environment and affect the health of human population and urban ecosystems but are also spread through runoff and leaching into non-contaminated areas. Urban lawns are the most distributed green infrastructure in the cities. Management of lawn system may either exacerbate the negative effects of contaminants on lawn functioning either help to withstand the toxic effects and maintain the lawn ecosystem health and the efficient release of ecosystem services. &amp;#160;&lt;/p&gt;&lt;p&gt;The aim of this study was to evaluate the interactions between the lawn management, the lawn functioning, and the release into the soil of typical urban contaminants. For this purpose, &lt;em&gt;Festuca arundinacea&lt;/em&gt; grass was planted in a turf-sand mixture with and without amendment addition (zeolite + vermicompost). To reproduce the impact of traffic-related contaminants in proximity of the road, pots were treated with a solution containing de-icing salt (NaCl) and 6 heavy metals (Zn, Cd, Pb, Cr, Cu, Ni), imitating road runoff solution. After contamination, half of pots was maintained at optimum soil water content (Smart irrigation), another half was left to periodical drying in order to simulate conditions with discontinuous watering (Periodical irrigation). The same experimental scheme was reproduced for unplanted soil. CO&lt;sub&gt;2&lt;/sub&gt; net ecosystem exchange (NEE), soil and ecosystem respiration as well as flux from unplanted soil (heterotrophic respiration) were measured shortly after the treatment (short-term) and up 3 months since the treatment start (long-term).&lt;/p&gt;&lt;p&gt;Soil amendment stimulated plant productivity and increased the efficiency of the system in C uptake (+56% NEE). A relevant reduction of NEE was observed from 14 to 40 days after the application of traffic-related contaminants in both amended and non amended pots. During this period the contaminants had the greatest impact on lawn NEE subjected to Periodic irrigation (-49% and -66% in amended and non amended pots, respectively), while lawn under Smart irrigation was less affected (-35% and -26% in amended and non amended pots, respectively). Different respiration sources (ecosystem respiration, soil respiration, heterotrophic respiration) were characterized by different sensitivity to management and contamination. Heterotrophic flux was not sensitive to soil amending but declined with contamination with enhanced negative effect under Smart irrigation. Response of ecosystem respiration to contamination was less pronounced in confront to soil respiration suggesting leaf-level buffering.&amp;#160; &amp;#160;&amp;#160;&lt;/p&gt;&lt;p&gt;Three months later,&amp;#160; the effect of contaminants on lawn gas exchange ceased for all treated pots. Instead, the irrigation effect persisted depending on whether pots were amended or not. In non amended pots NEE was reduced by 18% under Periodic irrigation, while this effect was not present in amended pots. We conclude, that performance of such green infrastructure as lawns in terms of C sequestration under multiple anthropogenic stressors could be efficiently improved through soil amending and irrigation control.&lt;/p&gt;&lt;p&gt;Current research was financially supported by RFBR No. 19-29-05187 and RSF No. 19-77-30012.&lt;/p&gt;

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