scholarly journals Aridity Decouples C:N:P Stoichiometry Across Multiple Trophic Levels in Terrestrial Ecosystems

Ecosystems ◽  
2017 ◽  
Vol 21 (3) ◽  
pp. 459-468 ◽  
Author(s):  
Manuel Delgado-Baquerizo ◽  
David J. Eldridge ◽  
Fernando T. Maestre ◽  
Victoria Ochoa ◽  
Beatriz Gozalo ◽  
...  
Keyword(s):  
Terrestrial Ecosystems ◽  
Trophic Levels ◽  
C:N:P Stoichiometry

scholarly journals Identifying appropriate sampling and modelling approaches for analysing distributional patterns of Antarctic terrestrial arthropods along the Victoria Land latitudinal gradient

2010 ◽  
Vol 22 (6) ◽  
pp. 742-748 ◽  
Author(s):  
Tancredi Caruso ◽  
Ian D. Hogg ◽  
Roberto Bargagli
Keyword(s):  
Abiotic Factors ◽  
Relevant Literature ◽  
Biotic Interactions ◽  
Terrestrial Ecosystems ◽  
Climatic Conditions ◽  
Trophic Levels ◽  
Terrestrial Arthropods ◽  
Victoria Land ◽  
Dispersal Capability ◽  
Modelling Techniques

AbstractBiotic communities in Antarctic terrestrial ecosystems are relatively simple and often lack higher trophic levels (e.g. predators); thus, it is often assumed that species’ distributions are mainly affected by abiotic factors such as climatic conditions, which change with increasing latitude, altitude and/or distance from the coast. However, it is becoming increasingly apparent that factors other than geographical gradients affect the distribution of organisms with low dispersal capability such as the terrestrial arthropods. In Victoria Land (East Antarctica) the distribution of springtail (Collembola) and mite (Acari) species vary at scales that range from a few square centimetres to regional and continental. Different species show different scales of variation that relate to factors such as local geological and glaciological history, and biotic interactions, but only weakly with latitudinal/altitudinal gradients. Here, we review the relevant literature and outline more appropriate sampling designs as well as suitable modelling techniques (e.g. linear mixed models and eigenvector mapping), that will more adequately address and identify the range of factors responsible for the distribution of terrestrial arthropods in Antarctica.

The role of interactions between trophic levels in determining the effects of UV-B on terrestrial ecosystems

1997 ◽  
pp. 296-308 ◽  
Author(s):  
Nigel D. Paul ◽  
Sharima Rasanayagam ◽  
Sandra A. Moody ◽  
Paul E. Hatcher ◽  
Peter G. Ayres
Keyword(s):  
Terrestrial Ecosystems ◽  
Trophic Levels

Multiple feedbacks due to biotic interactions across trophic levels can lead to persistent novel conditions that hinder restoration.

2020 ◽  
pp. 402-420
Author(s):  
Stephanie G. Yelenik ◽  
Carla M. D'Antonio ◽  
Evan M. Rehm ◽  
Iain R. Caldwell
Keyword(s):  
Species Interactions ◽  
Native Species ◽  
Biotic Interactions ◽  
Terrestrial Ecosystems ◽  
Trophic Levels ◽  
Native Grasses ◽  
Positive Feedbacks ◽  
Mesic Forest ◽  
Management Context ◽  
Multiple Challenges

Abstract Unlike traditional successional theory, Alternate Stable Equilibrium (ASE) theory posits that more than one community state is possible in a single environment, depending on the order that species arrive. ASE theory is often invoked in management situations where initial stressors have been removed, but native-dominated communities are not returning to degraded areas. Fundamental to this theory is the assumption that equilibria are maintained by positive feedbacks between colonizers and their environment. While ASE has been relatively well studied in aquatic ecosystems, more complex terrestrial systems offer multiple challenges, including species interactions across trophic levels that can lead to multiple feedbacks. Here, we discuss ASE theory as it applies to terrestrial, invaded ecosystems, and detail a case study from Hawai'i that exemplifies how species interactions can favour the persistence of invaders, and how an understanding of interactions and feedbacks can be used to guide management. Our system includes intact native-dominated mesic forest and areas cleared for pasture, planted with non-native grasses, and later planted with a monoculture of a native nitrogen-fixing tree in an effort to restore forests. We discuss interactions between birds, understorey fruiting native species, understorey non-native grasses, soils and bryophytes in separate feedback mechanisms, and explain our efforts to identify which of these feedbacks is most important to address in a management context. Finally, we suggest that using models can help overcome some of the challenges that terrestrial ecosystems pose when studying ASE.

scholarly journals Declines in an abundant aquatic insect, the burrowing mayfly, across major North American waterways

2020 ◽  
Vol 117 (6) ◽  
pp. 2987-2992 ◽  
Author(s):  
Phillip M. Stepanian ◽  
Sally A. Entrekin ◽  
Charlotte E. Wainwright ◽  
Djordje Mirkovic ◽  
Jennifer L. Tank ◽  
...  
Keyword(s):  
Mississippi River ◽  
Animal Movement ◽  
Aquatic Insect ◽  
Terrestrial Ecosystems ◽  
Trophic Levels ◽  
Western Lake ◽  
Annual Biomass ◽  
Emergence Event ◽  
Western Lake Erie

Seasonal animal movement among disparate habitats is a fundamental mechanism by which energy, nutrients, and biomass are transported across ecotones. A dramatic example of such exchange is the annual emergence of mayfly swarms from freshwater benthic habitats, but their characterization at macroscales has remained impossible. We analyzed radar observations of mayfly emergence flights to quantify long-term changes in annual biomass transport along the Upper Mississippi River and Western Lake Erie Basin. A single emergence event can produce 87.9 billion mayflies, releasing 3,078.6 tons of biomass into the airspace over several hours, but in recent years, production across both waterways has declined by over 50%. As a primary prey source in aquatic and terrestrial ecosystems, these declines will impact higher trophic levels and environmental nutrient cycling.

scholarly journals Trait-mediated trophic cascade creates enemy-free space for nesting hummingbirds

2015 ◽  
Vol 1 (8) ◽  
pp. e1500310 ◽  
Author(s):  
Harold F. Greeney ◽  
M. Rocio Meneses ◽  
Chris E. Hamilton ◽  
Eli Lichter-Marck ◽  
R. William Mannan ◽  
...  
Keyword(s):  
Climate Change ◽  
Habitat Fragmentation ◽  
Breeding Success ◽  
Indirect Effects ◽  
Trophic Cascade ◽  
Terrestrial Ecosystems ◽  
Trophic Levels ◽  
Ecological Communities ◽  
Top Predators ◽  
Enemy Free Space

The indirect effects of predators on nonadjacent trophic levels, mediated through traits of intervening species, are collectively known as trait-mediated trophic cascades. Although birds are important predators in terrestrial ecosystems, clear examples of trait-mediated indirect effects involving bird predators have almost never been documented. Such indirect effects are important for structuring ecological communities and are likely to be negatively impacted by habitat fragmentation, climate change, and other factors that reduce abundance of top predators. We demonstrate that hummingbirds in Arizona realize increased breeding success when nesting in association with hawks. An enemy-free nesting space is created when jays, an important source of mortality for hummingbird nests, alter their foraging behavior in the presence of their hawk predators.

Multiple feedbacks due to biotic interactions across trophic levels can lead to persistent novel conditions that hinder restoration.

2020 ◽  
pp. 402-420
Author(s):  
Stephanie G. Yelenik ◽  
◽  
Carla M. D’Antonio ◽  
Evan M. Rehm ◽  
Iain R. Caldwell ◽  
...  
Keyword(s):  
Species Interactions ◽  
Native Species ◽  
Biotic Interactions ◽  
Terrestrial Ecosystems ◽  
Trophic Levels ◽  
Native Grasses ◽  
Positive Feedbacks ◽  
Mesic Forest ◽  
Management Context ◽  
Multiple Challenges

Unlike traditional successional theory, Alternate Stable Equilibrium (ASE) theory posits that more than one community state is possible in a single environment, depending on the order that species arrive. ASE theory is often invoked in management situations where initial stressors have been removed, but native-dominated communities are not returning to degraded areas. Fundamental to this theory is the assumption that equilibria are maintained by positive feedbacks between colonizers and their environment. While ASE has been relatively well studied in aquatic ecosystems, more complex terrestrial systems offer multiple challenges, including species interactions across trophic levels that can lead to multiple feedbacks. Here, we discuss ASE theory as it applies to terrestrial, invaded ecosystems, and detail a case study from Hawai'i that exemplifies how species interactions can favour the persistence of invaders, and how an understanding of interactions and feedbacks can be used to guide management. Our system includes intact native-dominated mesic forest and areas cleared for pasture, planted with non-native grasses, and later planted with a monoculture of a native nitrogen-fixing tree in an effort to restore forests. We discuss interactions between birds, understorey fruiting native species, understorey non-native grasses, soils and bryophytes in separate feedback mechanisms, and explain our efforts to identify which of these feedbacks is most important to address in a management context. Finally, we suggest that using models can help overcome some of the challenges that terrestrial ecosystems pose when studying ASE.

Across-trophic variation of potassium, calcium and magnesium stoichiometric traits in a parasitism food chain across temperate and subtropical biomes

2015 ◽  
Vol 66 (12) ◽  
pp. 1290 ◽  
Author(s):  
Xiao Sun ◽  
Andrea Rosanoff ◽  
Chunjiang Liu
Keyword(s):  
Nutrient Dynamics ◽  
Climatic Factors ◽  
Eastern China ◽  
Terrestrial Ecosystems ◽  
Trophic Levels ◽  
Physiological Status ◽  
Plant Tissues ◽  
Mean Annual Temperature ◽  
Concentration Changes ◽  
Chinese Cork Oak

Potassium (K), calcium (Ca) and magnesium (Mg) are three macro-elements essential for plants and animals. The ratios K : Mg or K :  (Ca + Mg) are viewed as indices of physiological status in livestock animals. In plants, Ca, Mg and K concentrations can vary with climate in terrestrial ecosystems. Here, with a widespread tree species (Chinese cork oak, Quercus variabilis Blume) and an acorn predator (the weevil Curculio davidi Fairmaire), we investigate how K, Ca and Mg vary in soils, plant tissues (leaves and acorns) and a consumer (herbivore insects) with climatic variables induced by latitude (LAT) across the temperate–subtropical areas of eastern China. Concentrations of K, Ca and Mg in soils, leaves, acorns and weevil larvae showed different degrees of variation across the study area, but only Mg concentration increased significantly with rising LAT across all four trophic levels, albeit with varying slopes. With rising mean annual temperature (MAT) and precipitation (MAP), soil Ca significantly decreased, as did leaf and acorn K concentrations, whereas all four tropic levels showed significant decreases in Mg content with both MAT and MAP (P < 0.05–0.001). Leaf and acorn Ca : Mg showed significant relationships with LAT and MAT (P < 0.05–0.01). The K : (Mg + Ca) ratio in soils and weevil larvae increased linearly with MAP (P < 0.05), and acorn K : (Mg + Ca) ratio varied in a concave manner (P < 0.001). Our results suggest that variations of Ca, Mg and K in plant tissues and weevil larva across a study area of 20° LAT range were largely driven by climatic factors, and that Mg concentration changes in all four trophic levels with climate (and LAT) largely drive changes in soil, plant and consumer ratios between Mg, Ca and/or K. These results provide information on possible effects of climate change on nutrient dynamics in terrestrial ecosystems.

scholarly journals Rare earth elements (REE) in freshwater, marine, and terrestrial ecosystems in the eastern Canadian Arctic

2017 ◽  
Author(s):  
Gwyneth Anne MacMillan ◽  
John Chételat ◽  
Joel Heath ◽  
Raymond Mickpegak ◽  
Marc Amyot
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Canadian Arctic ◽  
Terrestrial Ecosystems ◽  
Trophic Levels ◽  
Carbon And Nitrogen ◽  
Northern Regions ◽  
Order Of Magnitude ◽  
Mining Projects ◽  
Eastern Canadian Arctic

ABSTRACTFew ecotoxicological studies exist for rare earth elements (REEs), particularly field-based studies on their bioaccumulation and food web dynamics. REE mining has led to significant environment impacts in several countries (China, Brazil, U.S.), yet little is known about the fate and transport of these contaminants of emerging concern. To understand how REEs behave in pristine northern food webs, we measured REE concentrations and carbon and nitrogen stable isotope ratios (∂15N, ∂13C) in biota from marine, freshwater, and terrestrial ecosystems of the eastern Canadian Arctic (N=339). Northern ecosystems are potentially vulnerable to REE enrichment from prospective mining projects at high latitudes. Wildlife harvesting and tissue sampling was partly conducted by local hunters through a community-based monitoring project. Results show that REE generally follow a coherent bioaccumulation pattern for sample tissues, with some anomalies for redox-sensitive elements (Ce, Eu). Highest REE concentrations were found at low trophic levels, especially in vegetation and aquatic invertebrates. Terrestrial herbivores, ringed seal, and fish had low REE levels in muscle tissue (<0.1 nmolg-1), yet accumulation was an order of magnitude higher in all liver tissues. Age- and length-dependent REE accumulation also suggest that REE uptake is faster than elimination for some species. Overall, REE bioaccumulation patterns appear to be species- and tissue-species, with limited potential for biomagnification. This study provides novel ecotoxicological data on the behaviour of REE in ecosystems and will be useful for environmental impact assessment of REE enrichment in northern regions.

Structural, dynamic and energetic differences among biotic communities dominated by macrophytes, planktonic algae and cyanobacteria

1995 ◽  
Vol 32 (4) ◽  
pp. 1-23 ◽  
Author(s):  
C. S. Reynolds
Keyword(s):  
Aquatic Vegetation ◽  
Open Water ◽  
Terrestrial Ecosystems ◽  
Trophic Levels ◽  
Vegetation Types ◽  
Structural Dynamic ◽  
Planktonic Algae ◽  
Primary Products ◽  
Alternative State ◽  
Micro Organisms

Differences in the composition and organisation of three mutually alternative aquatic vegetation types are examined, paying particular attention to the influence exerted through the food webs in regulating the transfer of primary products to the higher trophic levels. Whereas limnoplanktonic communities of open water, whether transferring primary products directly to animals or largely through micro-organisms, are founded upon near-climactic vegetation, shallow margins supporting macrophytes provide a pioneer-stage to terrestrial ecosystems. Small or shallow lakes are entirely ‘marginal’ and are susceptible to dominance by one hydroseral stage or another but with an outcome which depends upon the operating alternative state. These factors change in time or may be altered artificially, to drive the system towards another natural or regulated alternative steady state.

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