Seasonal variability in ecosystem functioning across estuarine gradients: The role of sediment communities and ecosystem processes

2020 ◽  
Vol 162 ◽  
pp. 105096
Author(s):  
Sebastiaan Mestdagh ◽  
Xiaoyu Fang ◽  
Karline Soetaert ◽  
Tom Ysebaert ◽  
Tom Moens ◽  
...  
Keyword(s):  
Seasonal Variability ◽  
Ecosystem Functioning ◽  
Ecosystem Processes ◽  
Estuarine Gradients

First comparison of quantitative estimates of termite biomass and abundance reveals strong intercontinental differences

2014 ◽  
Vol 30 (2) ◽  
pp. 143-152 ◽  
Author(s):  
Cecilia A.L. Dahlsjö ◽  
Catherine L. Parr ◽  
Yadvinder Malhi ◽  
Homathevi Rahman ◽  
Patrick Meir ◽  
...  
Keyword(s):  
Functional Groups ◽  
Functional Diversity ◽  
Ecosystem Processes ◽  
Global Scale ◽  
Species Density ◽  
Abundance Data ◽  
Standardized Protocol ◽  
Biogeographical Distribution ◽  
Belt Transect

Abstract:Termite species and functional groups differ among regions globally (the functional-diversity anomaly). Here we investigate whether similar differences in biomass and abundance of termites occur among continents. Biomass and abundance data were collected with standardized sampling in Cameroon, Malaysia and Peru. Data from Peru were original to this study, while data from Cameroon and Malaysia were compiled from other sources. Species density data were sampled using a standardized belt transect (100 × 2 m) while the biomass and abundance measurements were sampled using a standardized protocol based on 2 × 2-m quadrats. Biomass and abundance data confirmed patterns found for species density and thus the existence of the functional diversity anomaly: highest estimates for biomass and abundance were found in Cameroon (14.5 ± 7.90 g m−2 and 1234 ± 437 ind m−2) followed by Malaysia (0.719 ± 0.193 g m−2 and 327 ± 72 ind m−2) and then Peru (0.345 ± 0.103 g m−2 and 130 ± 39 ind m−2). The biomass and abundance for each functional group were significantly different across sites for most termite functional groups. Biogeographical distribution of lineages was the primary cause for the functional diversity anomaly with true soil-feeding termites dominating in Cameroon and the absence of fungus-growing termites from Peru. These findings are important as the biomass and abundance of functional groups may be linked to ecosystem processes. Although this study allowed for comparisons between data from different regions further comparable data are needed to enhance the understanding of the role of termites in ecosystem processes on a global scale.

scholarly journals Stochastic Assembly Leads to Alternative Communities with Distinct Functions in a Bioreactor Microbial Community

mBio ◽  
2013 ◽  
Vol 4 (2) ◽  
Author(s):  
Jizhong Zhou ◽  
Wenzong Liu ◽  
Ye Deng ◽  
Yi-Huei Jiang ◽  
Kai Xue ◽  
...  
Keyword(s):  
Community Structure ◽  
Microbial Community ◽  
Microbial Diversity ◽  
Microbial Community Structure ◽  
Community Assembly ◽  
Ecosystem Functioning ◽  
Dominant Role ◽  
Microbial Biodiversity ◽  
Stochastic Assembly

ABSTRACTThe processes and mechanisms of community assembly and its relationships to community functioning are central issues in ecology. Both deterministic and stochastic factors play important roles in shaping community composition and structure, but the connection between community assembly and ecosystem functioning remains elusive, especially in microbial communities. Here, we used microbial electrolysis cell reactors as a model system to examine the roles of stochastic assembly in determining microbial community structure and functions. Under identical environmental conditions with the same source community, ecological drift (i.e., initial stochastic colonization) and subsequent biotic interactions created dramatically different communities with little overlap among 14 identical reactors, indicating that stochastic assembly played dominant roles in determining microbial community structure. Neutral community modeling analysis revealed that deterministic factors also played significant roles in shaping microbial community structure in these reactors. Most importantly, the newly formed communities differed substantially in community functions (e.g., H2production), which showed strong linkages to community structure. This study is the first to demonstrate that stochastic assembly plays a dominant role in determining not only community structure but also ecosystem functions. Elucidating the links among community assembly, biodiversity, and ecosystem functioning is critical to understanding ecosystem functioning, biodiversity preservation, and ecosystem management.IMPORTANCEMicroorganisms are the most diverse group of life known on earth. Although it is well documented that microbial natural biodiversity is extremely high, it is not clear why such high diversity is generated and maintained. Numerous studies have established the roles of niche-based deterministic factors (e.g., pH, temperature, and salt) in shaping microbial biodiversity, the importance of stochastic processes in generating microbial biodiversity is rarely appreciated. Moreover, while microorganisms mediate many ecosystem processes, the relationship between microbial diversity and ecosystem functioning remains largely elusive. Using a well-controlled laboratory system, this study provides empirical support for the dominant role of stochastic assembly in creating variations of microbial diversity and the first explicit evidence for the critical role of community assembly in influencing ecosystem functioning. The results presented in this study represent important contributions to the understanding of the mechanisms, especially stochastic processes, involved in shaping microbial biodiversity.

Unified Framework II Ecosystem Processes: A Link Between Species and Landscape Diversity

2005 ◽  
Author(s):  
Robert Waide ◽  
Peter M. Groffman
Keyword(s):  
Landscape Ecology ◽  
Nutrient Cycling ◽  
Community Ecology ◽  
Energy Flow ◽  
Ecosystem Processes ◽  
Landscape Diversity ◽  
Ecosystem Ecology ◽  
Unified Framework ◽  
Ecosystem Diversity

The discipline of ecology can be subdivided into several subdisciplines, including community, ecosystem, and landscape ecology. While all the subdisciplines are important to the study of biodiversity, there is great variation in the extent to which their contributions have been analyzed. For example, the role of community ecology in biodiversity studies is well established. In community ecology, the entities of study are species that differ in their properties and generate a web of interactions that, in turn, organize the species into a community. Similar to community ecology, the contribution of landscape ecology to biodiversity is apparent. The entities of study, definable “patches,” are tangible. They differ in their properties and generate a web of interactions that organize the patches into a landscape mosaic. In contrast to community and landscape ecology, the role of ecosystem ecology in biodiversity is less apparent. In ecosystem ecology, it often is not clear what the entities are, and how they are organized. To the extent that ecosystem ecology focuses on energy flow and nutrient cycling, we can define fundamental entities as compartments and vectors in models that depict the flows of water, energy, and nutrients through communities. If we apply diversity criteria to these entities, we can use the term ecosystem diversity to refer to the number of compartments and vectors, the differences among them in type and size, and their organization in promoting energy flow or nutrient cycling. To our knowledge, ecosystem scientists have not yet developed criteria for ecosystem diversity similar to those used for species and landscape diversity. There has been some use of the term “ecosystem diversity” to refer to a diversity of ecosystems, implying a variety of habitats, landscapes, or biomes. As discussed above, we suggest that to define the role of ecosystem ecology in biodiversity studies, the approach should be to study the relationships among species, landscape, and ecosystem diversities (chapters 1 and 13). However, since the concept of ecosystem diversity awaits further development, we adopt a different approach for understanding the role of ecosystem science in biodiversity studies. In this chapter, we examine relationships among ecosystem processes, species diversity, and landscape diversity.

scholarly journals Interactive effects of foundation species on ecosystem functioning and stability in response to disturbance

2019 ◽  
Vol 286 (1913) ◽  
pp. 20191857 ◽  
Author(s):  
Anita Narwani ◽  
Marta Reyes ◽  
Aaron Louis Pereira ◽  
Hannele Penson ◽  
Stuart R. Dennis ◽  
...  
Keyword(s):  
Ecosystem Functioning ◽  
Foundation Species ◽  
Interactive Effects ◽  
Important Species ◽  
Nutrient Additions ◽  
The Face ◽  
Ecosystem Level ◽  
Primary Producer ◽  
Cyanobacterial Dominance

A major challenge in ecology is to understand determinants of ecosystem functioning and stability in the face of disturbance. Some important species can strongly shape community structure and ecosystem functioning, but their impacts and interactions on ecosystem-level responses to disturbance are less well known. Shallow ponds provide a model system in which to study the effects of such species because some taxa mitigate transitions between alternative ecosystem states caused by eutrophication. We performed pond experiments to test how two foundation species (a macrophyte and a mussel) affected the biomass of planktonic primary producers and its stability in response to nutrient additions. Individually, each species reduced phytoplankton biomass and tended to increase rates of recovery from disturbance, but together the species reversed these effects, particularly with larger nutrient additions. This reversal was mediated by high cyanobacterial dominance of the community and a resulting loss of trait evenness. Effects of the foundation species on primary producer biomass were associated with effects on other ecosystem properties, including turbidity and dissolved oxygen. Our work highlights the important role of foundation species and their interactive effects in determining responses of ecosystem functioning to disturbance.

scholarly journals Global distribution and conservation status of ecologically rare mammal and bird species

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Nicolas Loiseau ◽  
Nicolas Mouquet ◽  
Nicolas Casajus ◽  
Matthias Grenié ◽  
Maya Guéguen ◽  
...  
Keyword(s):  
Human Development ◽  
Rare Species ◽  
Human Development Index ◽  
Ecosystem Functioning ◽  
Conservation Status ◽  
Bird Species ◽  
Ecosystem Processes ◽  
Potential Contribution ◽  
Development Index

Abstract Identifying species that are both geographically restricted and functionally distinct, i.e. supporting rare traits and functions, is of prime importance given their risk of extinction and their potential contribution to ecosystem functioning. We use global species distributions and functional traits for birds and mammals to identify the ecologically rare species, understand their characteristics, and identify hotspots. We find that ecologically rare species are disproportionately represented in IUCN threatened categories, insufficiently covered by protected areas, and for some of them sensitive to current and future threats. While they are more abundant overall in countries with a low human development index, some countries with high human development index are also hotspots of ecological rarity, suggesting transboundary responsibility for their conservation. Altogether, these results state that more conservation emphasis should be given to ecological rarity given future environmental conditions and the need to sustain multiple ecosystem processes in the long-term.

scholarly journals Seasonal Variability in the Microbial Plankton Community in a Semienclosed Bay Affected by Upwelling: The Role of a Nutrient Trap

2020 ◽  
Vol 7 ◽  
Author(s):  
Francisco G. Figueiras ◽  
Isabel G. Teixeira ◽  
María Froján ◽  
Diana Zúñiga ◽  
Belén Arbones ◽  
...  
Keyword(s):  
Seasonal Variability ◽  
Plankton Community ◽  
Microbial Plankton

scholarly journals Seasonal variability of tropical wetland CH<sub>4</sub> emissions: the role of the methanogen-available carbon pool

2012 ◽  
Vol 9 (8) ◽  
pp. 2821-2830 ◽  
Author(s):  
A. A. Bloom ◽  
P. I. Palmer ◽  
A. Fraser ◽  
D. S. Reay
Keyword(s):  
Atmospheric Chemistry ◽  
Seasonal Variability ◽  
Transport Model ◽  
Global Scale ◽  
Plant Litter ◽  
Carbon Pool ◽  
Spatial And Temporal Variability ◽  
Ch4 Emissions ◽  
Available Carbon

Abstract. We develop a dynamic methanogen-available carbon model (DMCM) to quantify the role of the methanogen-available carbon pool in determining the spatial and temporal variability of tropical wetland CH4 emissions over seasonal timescales. We fit DMCM parameters to satellite observations of CH4 columns from SCIAMACHY CH4 and equivalent water height (EWH) from GRACE. Over the Amazon River basin we found substantial seasonal variability of this carbon pool (coefficient of variation = 28 ± 22%) and a rapid decay constant (φ = 0.017 day−1), in agreement with available laboratory measurements, suggesting that plant litter is likely the prominent methanogen carbon source over this region. Using the DMCM we derived global CH4 emissions for 2003–2009, and determined the resulting seasonal variability of atmospheric CH4 on a global scale using the GEOS-Chem atmospheric chemistry and transport model. First, we estimated that tropical emissions amounted to 111.1 Tg CH4 yr−1, of which 24% was emitted from Amazon wetlands. We estimated that annual tropical wetland emissions increased by 3.4 Tg CH4 yr−1 between 2003 and 2009. Second, we found that the model was able to reproduce the observed seasonal lag of CH4 concentrations peaking 1–3 months before peak EWH values. We also found that our estimates of CH4 emissions substantially improved the comparison between the model and observed CH4 surface concentrations (r = 0.9). We anticipate that these new insights from the DMCM represent a fundamental step in parameterising tropical wetland CH4 emissions and quantifying the seasonal variability and future trends of tropical CH4 emissions.

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