scholarly journals Ecosystem-level controls on root-rhizosphere respiration

2013 ◽  
Vol 199 (2) ◽  
pp. 339-351 ◽  
Author(s):  
Francesca Hopkins ◽  
Miquel A. Gonzalez-Meler ◽  
Charles E. Flower ◽  
Douglas J. Lynch ◽  
Claudia Czimczik ◽  
...  
Keyword(s):  
Rhizosphere Respiration ◽  
Ecosystem Level

Ecosystems processes

2018 ◽  
Author(s):  
Karen J. Esler ◽  
Anna L. Jacobsen ◽  
R. Brandon Pratt
Keyword(s):  
Ecosystem Function ◽  
Mineral Nutrients ◽  
Structure And Function ◽  
Water Dynamics ◽  
Ecosystem Level ◽  
Key Drivers ◽  
And Function ◽  
Mediterranean Type Ecosystems

Ecosystems are assemblages of organisms interacting with one another and their environment (Chapter 1). Key to the functioning of ecosystems is the flow of energy, carbon, mineral nutrients, and water in these systems. The numerous processes involved are chiefly driven by climate, soil, and fire (Chapter 2). In cases where the key drivers are the same in different areas, then ecosystems should converge in their structure and function, which has been a motivation for comparing across mediterranean-type climate (MTC) regions. Convergence of MTC regions has been evaluated, but such comparisons at the ecosystem level are challenging because ecosystems are complex and dynamic entities. Here we review carbon, nutrient, and water dynamics of mediterranean-type ecosystems in the context of ecosystem function. As nutrients in soils are low in some MTC regions, we review how this has led to unique adaptations to meet this challenge.

scholarly journals Biological Control of Pest Non-Marine Molluscs: A Pacific Perspective on Risks to Non-Target Organisms

Insects ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 583
Author(s):  
Carl C. Christensen ◽  
Robert H. Cowie ◽  
Norine W. Yeung ◽  
Kenneth A. Hayes
Keyword(s):  
Biological Control ◽  
Environmental Impacts ◽  
Pacific Islands ◽  
Generalist Predators ◽  
Snail Species ◽  
Marine Mollusk ◽  
The Pacific ◽  
History Of ◽  
Ecosystem Level ◽  
Scientific Framework

Classic biological control of pest non-marine mollusks has a long history of disastrous outcomes, and despite claims to the contrary, few advances have been made to ensure that contemporary biocontrol efforts targeting mollusks are safe and effective. For more than half a century, malacologists have warned of the dangers in applying practices developed in the field of insect biological control, where biocontrol agents are often highly host-specific, to the use of generalist predators and parasites against non-marine mollusk pests. Unfortunately, many of the lessons that should have been learned from these failed biocontrol programs have not been rigorously applied to contemporary efforts. Here, we briefly review the failures of past non-marine mollusk biocontrol efforts in the Pacific islands and their adverse environmental impacts that continue to reverberate across ecosystems. We highlight the fact that none of these past programs has ever been demonstrated to be effective against targeted species, and at least two (the snails Euglandina spp. and the flatworm Platydemus manokwari) are implicated in the extinction of hundreds of snail species endemic to Pacific islands. We also highlight other recent efforts, including the proposed use of sarcophagid flies and nematodes in the genus Phasmarhabditis, that clearly illustrate the false claims that past bad practices are not being repeated. We are not making the claim that biocontrol programs can never be safe and effective. Instead, we hope that in highlighting the need for robust controls, clear and measurable definitions of success, and a broader understanding of ecosystem level interactions within a rigorous scientific framework are all necessary before claims of success can be made by biocontrol advocates. Without such amendments to contemporary biocontrol programs, it will be impossible to avoid repeating the failures of non-marine mollusk biocontrol programs to date.

scholarly journals Scarcity of scale-free topology is universal across biochemical networks

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Harrison B. Smith ◽  
Hyunju Kim ◽  
Sara I. Walker
Keyword(s):  
Large Body ◽  
Biochemical Networks ◽  
Biological Organization ◽  
Scale Free ◽  
Levels Of Organization ◽  
Common Structure ◽  
Domains Of Life ◽  
Ecosystem Level ◽  
Different Levels ◽  
Organizing Principles

AbstractBiochemical reactions underlie the functioning of all life. Like many examples of biology or technology, the complex set of interactions among molecules within cells and ecosystems poses a challenge for quantification within simple mathematical objects. A large body of research has indicated many real-world biological and technological systems, including biochemistry, can be described by power-law relationships between the numbers of nodes and edges, often described as “scale-free”. Recently, new statistical analyses have revealed true scale-free networks are rare. We provide a first application of these methods to data sampled from across two distinct levels of biological organization: individuals and ecosystems. We analyze a large ensemble of biochemical networks including networks generated from data of 785 metagenomes and 1082 genomes (sampled from the three domains of life). The results confirm no more than a few biochemical networks are any more than super-weakly scale-free. Additionally, we test the distinguishability of individual and ecosystem-level biochemical networks and show there is no sharp transition in the structure of biochemical networks across these levels of organization moving from individuals to ecosystems. This result holds across different network projections. Our results indicate that while biochemical networks are not scale-free, they nonetheless exhibit common structure across different levels of organization, independent of the projection chosen, suggestive of shared organizing principles across all biochemical networks.

scholarly journals Coral Communities as Indicators of Ecosystem-Level Impacts of the Deepwater Horizon Spill

BioScience ◽  
2014 ◽  
Vol 64 (9) ◽  
pp. 796-807 ◽  
Author(s):  
Charles R. Fisher ◽  
Amanda W. J. Demopoulos ◽  
Erik E. Cordes ◽  
Iliana B. Baums ◽  
Helen K. White ◽  
...  
Keyword(s):  
Deepwater Horizon ◽  
Coral Communities ◽  
Ecosystem Level

scholarly journals Trophic control of cryptic coralline algal diversity

2019 ◽  
Vol 116 (30) ◽  
pp. 15080-15085 ◽  
Author(s):  
Katharine R. Hind ◽  
Samuel Starko ◽  
Jenn M. Burt ◽  
Matthew A. Lemay ◽  
Anne K. Salomon ◽  
...  
Keyword(s):  
Algal Species ◽  
Trophic Dynamics ◽  
Kelp Forests ◽  
Negative Consequences ◽  
Food Web Structure ◽  
Nearshore Ecosystems ◽  
Keystone Predation ◽  
Ecological Patterns ◽  
Ecosystem Level ◽  
Algal Assemblages

Understanding how trophic dynamics drive variation in biodiversity is essential for predicting the outcomes of trophic downgrading across the world’s ecosystems. However, assessing the biodiversity of morphologically cryptic lineages can be problematic, yet may be crucial to understanding ecological patterns. Shifts in keystone predation that favor increases in herbivore abundance tend to have negative consequences for the biodiversity of primary producers. However, in nearshore ecosystems, coralline algal cover increases when herbivory is intense, suggesting that corallines may uniquely benefit from trophic downgrading. Because many coralline algal species are morphologically cryptic and their diversity has been globally underestimated, increasing the resolution at which we distinguish species could dramatically alter our conclusions about the consequences of trophic dynamics for this group. In this study, we used DNA barcoding to compare the diversity and composition of cryptic coralline algal assemblages at sites that differ in urchin biomass and keystone predation by sea otters. We show that while coralline cover is greater in urchin-dominated sites (or “barrens”), which are subject to intense grazing, coralline assemblages in these urchin barrens are significantly less diverse than in kelp forests and are dominated by only 1 or 2 species. These findings clarify how food web structure relates to coralline community composition and reconcile patterns of total coralline cover with the widely documented pattern that keystone predation promotes biodiversity. Shifts in coralline diversity and distribution associated with transitions from kelp forests to urchin barrens could have ecosystem-level effects that would be missed by ignoring cryptic species’ identities.

scholarly journals Water release through plant roots: new insights into its consequences at the plant and ecosystem level

2012 ◽  
Vol 193 (4) ◽  
pp. 830-841 ◽  
Author(s):  
Iván Prieto ◽  
Cristina Armas ◽  
Francisco I. Pugnaire
Keyword(s):  
Plant Roots ◽  
Water Release ◽  
Ecosystem Level
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