scholarly journals Marine biodiversity and ecosystem functioning: what’s known and what’s next?

2014 ◽  
Author(s):  
Lars Gamfeldt ◽  
Jonathan S Lefcheck ◽  
Jarrett E K Byrnes ◽  
Bradley J Cardinale ◽  
J. Emmett Duffy ◽  
...  
Keyword(s):  
Species Richness ◽  
Meta Analysis ◽  
Nutrient Release ◽  
Marine Ecosystems ◽  
Trophic Levels ◽  
Marine Biodiversity ◽  
Full Data ◽  
Negative Effect ◽  
Marine Realm ◽  
Pervasive Loss

Marine ecosystems are experiencing rapid and pervasive loss of species. Understanding the consequences of species loss is critical to effectively managing these systems. Over the last several years, numerous experimental manipulations of species richness have been performed, yet existing quantitative syntheses have focused on a just a subset of processes measured in experiments and, as such, have not summarized the full data available from marine systems. Here, we present the results of a meta-analysis of 174 marine experiments from 42 studies that have manipulated the species richness of organisms across a range of taxa and trophic levels and analysed the consequences for various ecosystem processes (categorised as production, consumption or biogeochemical fluxes). Our results show that, generally, mixtures of species tend to enhance levels of ecosystem function relative to the average component species in monoculture, but have no or negative effect on functioning relative to the ‘highest-performing' species. These results are largely consistent with those from other syntheses, and extend conclusions to ecological functions that are most commonly measured in the marine realm (e.g. nutrient release from sediment bioturbation). For experiments that manipulated three or more levels of richness, we attempted to discern the functional form of the BEF relationship. We found that, for response variables categorised as consumption, a power-function best described the relationship, which is also consistent with previous findings. However, we identified a linear relationship between richness and production. Combined, our results suggest that losses of species will, on average, tend to alter the functioning of marine ecosystems. We outline several research frontiers that will allow us to more fully understand how, why, and when diversity may drive the functioning of marine ecosystems.

scholarly journals Marine biodiversity and ecosystem functioning: what’s known and what’s next?

2014 ◽  
Author(s):  
Lars Gamfeldt ◽  
Jonathan S Lefcheck ◽  
Jarrett E K Byrnes ◽  
Bradley J Cardinale ◽  
J. Emmett Duffy ◽  
...  
Keyword(s):  
Species Richness ◽  
Meta Analysis ◽  
Nutrient Release ◽  
Marine Ecosystems ◽  
Trophic Levels ◽  
Marine Biodiversity ◽  
Full Data ◽  
Negative Effect ◽  
Marine Realm ◽  
Pervasive Loss

Marine ecosystems are experiencing rapid and pervasive loss of species. Understanding the consequences of species loss is critical to effectively managing these systems. Over the last several years, numerous experimental manipulations of species richness have been performed, yet existing quantitative syntheses have focused on a just a subset of processes measured in experiments and, as such, have not summarized the full data available from marine systems. Here, we present the results of a meta-analysis of 174 marine experiments from 42 studies that have manipulated the species richness of organisms across a range of taxa and trophic levels and analysed the consequences for various ecosystem processes (categorised as production, consumption or biogeochemical fluxes). Our results show that, generally, mixtures of species tend to enhance levels of ecosystem function relative to the average component species in monoculture, but have no or negative effect on functioning relative to the ‘highest-performing' species. These results are largely consistent with those from other syntheses, and extend conclusions to ecological functions that are most commonly measured in the marine realm (e.g. nutrient release from sediment bioturbation). For experiments that manipulated three or more levels of richness, we attempted to discern the functional form of the BEF relationship. We found that, for response variables categorised as consumption, a power-function best described the relationship, which is also consistent with previous findings. However, we identified a linear relationship between richness and production. Combined, our results suggest that losses of species will, on average, tend to alter the functioning of marine ecosystems. We outline several research frontiers that will allow us to more fully understand how, why, and when diversity may drive the functioning of marine ecosystems.

Impacts of nitrogen deposition on terrestrial plant diversity: a meta-analysis in China

2019 ◽  
Vol 12 (6) ◽  
pp. 1025-1033 ◽  
Author(s):  
Wen-Juan Han ◽  
Jia-Yu Cao ◽  
Jin-Liang Liu ◽  
Jia Jiang ◽  
Jian Ni
Keyword(s):  
Species Richness ◽  
Plant Diversity ◽  
Meta Analysis ◽  
N Deposition ◽  
Shannon Index ◽  
N Addition ◽  
Terrestrial Plant ◽  
Multiple Dimensions ◽  
Negative Effect ◽  
Experiment Duration

AbstractAimsWith the global atmospheric nitrogen (N) deposition increasing, the effect of N deposition on terrestrial plant diversity has been widely studied. Some studies have reviewed the effects of N deposition on plant species diversity; however, all studies addressed the effects of N deposition on plant community focused on species richness in specific ecosystem. There is a need for a systematic meta-analysis covering multiple dimensions of plant diversity in multiple climate zones and ecosystems types. Our goal was to quantify changes in species richness, evenness and uncertainty in plant communities in response to N addition across different environmental and experimental contexts.MethodsWe performed a meta-analysis of 623 experimental records published in English and Chinese journals to evaluate the response of terrestrial plant diversity to the experimental N addition in China. Three metrics were used to quantify the change in plant diversity: species richness (SR), evenness (Pielou index) uncertainty (Shannon index).Important FindingsResults showed that (i) N addition negatively affected SR in temperate, Plateau zones and subtropical zone, but had no significant effect on Shannon index in subtropical zones; (ii) N addition decreased SR, Shannon index and Pielou index in grassland, and the negative effect of N addition on SR was stronger in forest than in grassland; (iii) N addition negatively affected plant diversity (SR, Shannon index and Pielou index) in the long term, whereas it did not affect plant diversity in the short term. Furthermore, the increase in N addition levels strengthened the negative effect of N deposition on plant diversity with long experiment duration; and (iv) the negative effect of ammonium nitrate (NH4NO3) addition on SR was stronger than that of urea (CO(NH2)2) addition, but the negative effect of NH4NO3 addition on Pielou index was weaker than that of CO(NH2)2 addition. Our results indicated that the effects of N addition on plant diversity varied depending on climate zones, ecosystem types, N addition levels, N type and experiment duration. This underlines the importance of integrating multiple dimensions of plant diversity and multiple factors into assessments of plant diversity to global environmental change.

scholarly journals Marine biodiversity–ecosystem functions under uncertain environmental futures

2010 ◽  
Vol 365 (1549) ◽  
pp. 2107-2116 ◽  
Author(s):  
Mark T. Bulling ◽  
Natalie Hicks ◽  
Leigh Murray ◽  
David M. Paterson ◽  
Dave Raffaelli ◽  
...  
Keyword(s):  
Climate Change ◽  
Carbon Dioxide ◽  
Species Richness ◽  
Ecosystem Functioning ◽  
Atmospheric Carbon Dioxide ◽  
Nutrient Release ◽  
Future Climate Change ◽  
Marine Biodiversity ◽  
Invertebrate Species ◽  
Atmospheric Carbon

Anthropogenic activity is currently leading to dramatic transformations of ecosystems and losses of biodiversity. The recognition that these ecosystems provide services that are essential for human well-being has led to a major interest in the forms of the biodiversity–ecosystem functioning relationship. However, there is a lack of studies examining the impact of climate change on these relationships and it remains unclear how multiple climatic drivers may affect levels of ecosystem functioning. Here, we examine the roles of two important climate change variables, temperature and concentration of atmospheric carbon dioxide, on the relationship between invertebrate species richness and nutrient release in a model benthic estuarine system. We found a positive relationship between invertebrate species richness and the levels of release of NH 4 -N into the water column, but no effect of species richness on the release of PO 4 -P. Higher temperatures and greater concentrations of atmospheric carbon dioxide had a negative impact on nutrient release. Importantly, we found significant interactions between the climate variables, indicating that reliably predicting the effects of future climate change will not be straightforward as multiple drivers are unlikely to have purely additive effects, resulting in increased levels of uncertainty.

scholarly journals Trophic cascades and connectivity in coastal benthic marine ecosystems: a meta-analysis of experimental and observational research

2020 ◽  
Author(s):  
Aaron Matthius Eger ◽  
Julia Kathleen Baum
Keyword(s):  
Abiotic Factors ◽  
Meta Analysis ◽  
Trophic Cascades ◽  
Marine Ecosystems ◽  
Trophic Levels ◽  
Observational Research ◽  
Biotic Factors ◽  
Population Response ◽  
High Nutrient ◽  
Abiotic And Biotic Factors

Predators often exert top-down control on lower trophic levels, such that their removal or addition can trigger trophic cascades. Despite coastal ecosystems containing well known trophic cascades, the abiotic and biotic factors governing the occurrence and strength of these cascades are still unclear. We worked to explain the variability of trophic cascades in benthic marine ecosystems by conducting a meta-analysis of experimental (N = 17) and observational (N = 22) studies that recorded herbivore and producer populations in the presence and absence of a first level predator. From these data (147 predator-herbivore-producer measurements), we show that, although not as strong as previously estimated, the presence of predators decreased herbivore populations between 2.1 to 4.76 times and increased producer populations by 1.62 to 2.83 times. Biotic factors related to species’ body size were most influential in determining herbivore population response to predator presence, while abiotic factors, including nutrient concentration, best determined the producer population response. Our results also show producers responded more intensely to changes in herbivore populations in high nutrient and low temperature environments. Looking at populations in marine reserves we found that herbivore populations in reserves were 3.00 times lower on average, compared to areas outside the reserve, while producer populations were on average 1.84 times higher. Overall, this work advances our understanding of the factors modulating trophic cascade strength, demonstrates that reserves can have ecosystem wide impacts, and establishes a new baseline of trophic cascades in benthic marine systems.

scholarly journals Trophic cascades and connectivity in coastal benthic marine ecosystems: a meta-analysis of experimental and observational research

2020 ◽  
Vol 656 ◽  
pp. 139-152 ◽  
Author(s):  
AM Eger ◽  
JK Baum
Keyword(s):  
Abiotic Factors ◽  
Meta Analysis ◽  
Trophic Cascades ◽  
Past Research ◽  
Marine Ecosystems ◽  
Trophic Levels ◽  
Observational Research ◽  
Biotic Factors ◽  
Population Responses ◽  
Abiotic And Biotic Factors

Predators can exert top-down control on lower trophic levels, such that their removal or addition may trigger trophic cascades. Despite coastal ecosystems containing well known trophic cascades, there remains uncertainty about the abiotic and biotic factors governing the occurrence and strength of these cascades. Here, we sought to explain the variability of trophic cascades in benthic marine ecosystems by conducting a meta-analysis of experimental (n = 17) and observational (n = 22) studies that recorded herbivore and producer populations in the presence and absence of a predator. From these data (147 predator-herbivore-producer measurements), we show that predators decreased herbivore populations between 2.1-4.76 times and increased producer populations by 1.62-2.83 times their original biomass, abundance, or density. Contrary to past research, these values are comparable to other ecosystems. Biotic factors related to species body size were most influential in determining herbivore population responses to the presence of predators, while abiotic factors, including nutrient concentration, best determined producer population responses. Our results also show that producers responded more strongly to changes in herbivore populations in high-nutrient and low-temperature environments. We found that herbivore populations in marine reserves were 2.83 times lower on average compared to areas outside the reserve, while producer populations were on average 1.90 times higher. Overall, this work advances understanding of factors modulating trophic cascade strength, demonstrates that reserves can have ecosystem-wide impacts, and provides new information about the average strength of trophic cascades in benthic marine ecosystems.

Plant diversity and species richness of Ljubljana marsh grasslands under the influence of different cutting and fertilizing regimes

2009 ◽  
Vol 57 (2) ◽  
pp. 197-203 ◽  
Author(s):  
T. Sinkovč
Keyword(s):  
Species Richness ◽  
Plant Diversity ◽  
Grassland Management ◽  
Botanical Composition ◽  
Significant Negative Effect ◽  
Negative Effect ◽  
Cutting Regimes ◽  
N Rates ◽  
Exploitation Intensity ◽  
Plot Design

The botanical composition of grasslands determines the agronomic and natural values of swards. Good grassland management usually improves herbage value, but on the other hand it frequently decreases the plant diversity and species richness in the swards. In 1999 a field trial in a split-plot design with four replicates was therefore established on the Arrhenatherion type of vegetation in Ljubljana marsh meadows in order to investigate this relationship. Cutting regimes (2 cuts — with normal and delayed first cut, 3 cuts and 4 cuts per year) were allocated to the main plots and fertiliser treatments (zero fertiliser — control, PK and NPK with 2 or 3 N rates) were allocated to the sub-plots. The results at the 1 st cutting in the 5 th trial year were as follows: Fertilising either with PK or NPK had no significant negative effect on plant diversity in any of the cutting regimes. In most treatments the plant number even increased slightly compared to the control. On average, 20 species were listed on both unfertilised and fertilised swards. At this low to moderate level of exploitation intensity, the increased number of cuts had no significant negative effect on plant diversity either (19 species at 2 cuts vs. 20 species at 3 or 4 cuts). PK fertilisation increased the proportion of legumes in the herbage in the case of 2 or 3 cuts. The proportion of grasses in the herbage increased in all the fertilisation treatments with an increased numbers of cuts. Fertiliser treatment considerably reduced the proportion of marsh horsetail ( Equisetum palustre ) in the herbage of the meadows. This effect was even more pronounced at higher cut numbers. The proportion of Equisetum palustre in the herbage was the highest in the unfertilised sward with 2 cuts (26.4 %) and the lowest in the NPK-fertilised sward with 4 cuts (1.4%).

Linking fish and crustacean taxonomic composition with seasonal contrasts in the soft-bottom intertidal zone

2020 ◽  
Author(s):  
M. A. Gondal ◽  
S. Iqbal ◽  
U. Atique ◽  
N. U. Saher ◽  
N. A. Qureshi ◽  
...  
Keyword(s):  
Species Richness ◽  
Water Temperature ◽  
Fish Species ◽  
Diversity Index ◽  
Taxonomic Composition ◽  
Primary Objective ◽  
Negative Effect ◽  
Fish Species Composition ◽  
One Year ◽  
Sw Monsoon

Abstract The primary objective of this study was to investigate the seasonal fish and crustacean variations concerning taxonomic composition, species richness, and diversity in sandy beach habitat. For this purpose, we investigated the Sonmiani Hor lagoon area during four distinct seasons, i.e., northeast (NE) monsoon, pre-monsoon, south-west (SW) monsoon, and post-monsoon for one year. During each haul, the net was pulled about 100m along the beach in 0.5m depth. The results showed a strong linear correlation between the diversity index and equitability in fishes (r = 0.978). The diversity index was strong negatively correlated with the abundance and biomass (r = -0.978, -0.972, respectively). The physical attributes like sea surface water temperature and salinity showed a strong negative effect on species assemblages (r = -0.981 and -0.943, respectively). The mean air and water temperature illustrated approximately 3°C difference during NE and pre-monsoon seasons. However, salinity, pH, and electrical conductivity did not show any significant seasonal variabilities. Under the ecological indices, the fish species displayed higher diversity (H’ = 3.19) during SW monsoon, whereas the lowest diversity was observed during pre-monsoon (H’ = 1.58). The equitability and species richness, however, remained more noticeable during SW monsoon (J’ = 0.81). The total number of individuals of fish and crustaceans reached 4799 with 3813 fish individuals and 986 individuals of crustaceans. A total of 27 families of fish while five crustacean families comprising of 30 genera and 38 fish species while ten genera and 17 species of crustaceans were recorded. Liza subviridis displayed the highest abundance among the sampled fish species. In conclusion, fish species constituted a significant part of the coastal fauna in the study area. The seasonal variations displayed distinct variations in fish species composition and diversity.

Effects of nitrogen deposition on litter decomposition and nutrient release mediated by litter types and seasonal change in a temperate forest

2020 ◽  
Vol 100 (1) ◽  
pp. 11-25 ◽  
Author(s):  
Guoyong Yan ◽  
Xiongde Dong ◽  
Binbin Huang ◽  
Honglin Wang ◽  
Ziming Hong ◽  
...  
Keyword(s):  
Mass Loss ◽  
Litter Decomposition ◽  
Nutrient Release ◽  
N Deposition ◽  
Pinus Koraiensis ◽  
N Addition ◽  
Entire Study ◽  
Mixed Litter ◽  
Negative Effect ◽  
Four Levels

We conducted a field experiment with four levels of simulated nitrogen (N) deposition (0, 2.5, 5, and 7.5 g N m−2 yr−1, respectively) to investigate the response of litter decomposition of Pinus koraiensis (PK), Tilia amurensis (TA), and their mixture to N deposition during winter and growing seasons. Results showed that N addition significantly increased the mass loss of PK litter and significantly decreased the mass loss of TA litter throughout the 2 yr decomposition processes, which indicated that the different responses in the decomposition of different litters to N addition can be species specific, potentially attributed to different litter chemistry. The faster decomposition of PK litter with N addition occurred mainly in the winter, whereas the slower decomposition of TA litter with N addition occurred during the growing season. Moreover, N addition had a positive effect on the release of phosphorus, magnesium, and manganese for PK litter and had a negative effect on the release of carbon, iron, and lignin for TA litter. Decomposition and nutrient release from mixed litter with N addition showed a non-additive effect. The mass loss from litter in the first winter and over the entire study correlated positively with the initial concentration of cellulose, lignin, and certain nutrients in the litter, demonstrating the potential influence of different tissue chemistries.

scholarly journals Effect of plateletpheresis on hematocrit, hemoglobin and erythrocyte count: Meta-analysis 1980–2018

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Alejandro Gil-Betacur ◽  
Carmen Yulieth Mantilla-Gutiérrez ◽  
Jaiberth Antonio Cardona-Arias
Keyword(s):  
Blood Cell ◽  
Cell Count ◽  
Red Blood Cell ◽  
Meta Analysis ◽  
Erythrocyte Count ◽  
Blood Cell Count ◽  
Selection Processes ◽  
Negative Effect ◽  
Red Blood Cell Count ◽  
The Mean

AbstractThe effects of platelet donation by apheresis on different parameters of the erythrogram are still unclear. The objective was to meta-analyze the effect of plateletpheresis on hematocrit, hemoglobin, and erythrocyte count, with a systematic review with random effects meta-analysis of the mean difference. The PRISMA guidelines were considered, as well as 133 search strategies on four different databases. Reproducibility was guaranteed and methodological quality was evaluated. Heterogeneity was evaluated with Galbraith and DerSimonian-Laird’s, publication bias with a funnel plot and a Begg’s test, sensitivity analysis and a cumulative meta-analysis were also conducted. Eighteen (18) articles were included, 17 evaluated the effects on hematocrit in 2,564 donors; 13 on hemoglobin in 1,640 donors; and 4 on red blood cell count in 243 donors. A decrease of 2.26% (CI95% = 2.11–2.41) was observed in hematocrit, of 0.80 g/dL (CI95% = 0.75–0.86) in hemoglobin and −0.21 × 1012/L (CI95% = −0.13; −0.29) in red blood cell count. Plateletpheresis has a negative effect on the erythrogram parameters, explained by blood loss in the kits used for the procedure and cell lysis. Such evidence is relevant to secure the efficiency and safety of the procedure, improve selection processes or determine the number of donations that can be performed without affecting donors’ health.

Effects of trophic status and wetland morphology, hydroperiod, and water chemistry on mercury concentrations in fish

2000 ◽  
Vol 57 (1) ◽  
pp. 171-180 ◽  
Author(s):  
Joel W Snodgrass ◽  
Charles H Jagoe ◽  
A Lawrence Bryan, Jr. ◽  
Heather A Brant ◽  
J Burger
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Water Chemistry ◽  
Maximum Depth ◽  
Trophic Levels ◽  
Whole Body ◽  
Regression Analyses ◽  
Negative Effects ◽  
Depression Wetlands ◽  
Negative Effect

We sampled fish and selected water chemistry variables (dissolved organic carbon, sulfate, and pH) in nine southeastern depression wetlands to determine relationships among wetland morphology (surface area and maximum depth), hydrology, water chemistry, and bioaccumulation of mercury (Hg) in fishes. We concentrated on three fish species representing the range of trophic levels occupied by fish in southeastern depression wetlands. Whole-body Hg concentrations were lowest in lake chubsucker (Erimyzon sucetta), a benthic detritivore, and highest in redfin pickerel (Esox americanus americanus), a top carnivore. However, variation in Hg concentrations among wetlands was greater than variation among species. Regression analyses indicated that maximum depth and hydroperiod accounted for significant portions of variation among wetlands in standardized lake chubsucker and redfin pickerel Hg concentrations. Maximum depth and dissolved organic carbon had a negative effect on standardized Hg concentrations in mud sunfish (Acantharchus pomotis). Path analysis confirmed the results of regression analyses, with maximum depth and hydroperiod having relatively large direct negative effects on Hg concentrations. Our results suggest that leaching of Hg from sediments during the drying and reflooding cycle and binding of Hg species by dissolved organic carbon in the water column are primary factors controlling the bioavailability of Hg in southeastern depression wetlands.

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