scholarly journals Top-down effects of foraging decisions on local, landscape and regional biodiversity of resources (DivGUD)

2021 ◽  
Author(s):  
Jana Eccard ◽  
Clara Ferreira ◽  
Andres Peredo Arce ◽  
Melanie Dammhahn
Keyword(s):  
Foraging Behaviour ◽  
Spatial Scales ◽  
Functional Trait ◽  
Trophic Levels ◽  
Wild Rodents ◽  
Cascading Effects ◽  
Giving Up Density ◽  
Predation Effects ◽  
Novel Concept ◽  
Adaptive Foraging

Foraging by consumers acts as a biotic filtering mechanism for biodiversity at the trophic level of resources. Variation in foraging behaviour have cascading effects on abundance, diversity, and functional trait composition of the community of resource species. Here we propose diversity at giving-up density (DivGUD), when foragers quit exploring a patch, as a novel concept and simple measure to quantify these effects at multiple spatial scales. In experimental landscapes, patch residency of wild rodents decreased local α-DivGUD (via elevated mortality of species with large seeds) and regional γ-DivGUD, while dissimilarity among patches in a landscape (ß-DivGUD) increased. Thus, DivGUD provides a framework linking theories of adaptive foraging behaviour with community ecology allowing to investigate cascading indirect predation effects across multiple trophic levels e.g. the ecology-of-fear framework; feedbacks between functional trait composition of resource species and consumer communities; and effects of inter-individual differences among foragers on the biodiversity of resource communities.

scholarly journals Giving-up diversity (GUDiv): top-down effects of foraging decisions on local, landscape and regional biodiversity of resources

2021 ◽  
Author(s):  
Jana Eccard ◽  
Clara Ferreira ◽  
Andres Peredo Arce ◽  
Melanie Dammhahn
Keyword(s):  
Foraging Behaviour ◽  
Functional Trait ◽  
Spatial Diversity ◽  
Trophic Levels ◽  
Community Effects ◽  
Wild Rodents ◽  
Cascading Effects ◽  
Predation Effects ◽  
Novel Concept ◽  
Adaptive Foraging

Foraging by consumers has direct effects on the community of their resource species, and may serve as a biotic filtering mechanism of diversity. Determinants of foraging behaviour may thus have cascading effects on abundance, diversity, and functional trait composition of the resource community. Here we propose giving-up diversity (GUDiv) as a novel concept and simple measure to quantify community effects of foraging at multiple spatial diversity scales. GUDiv provides a framework linking theories of adaptive foraging behaviour with community ecology. In experimental resource landscapes we showcase effects of patch residency of foraging wild rodents on α-GUDiv, ß-GUDiv and γ- GUDiv, and on functional trait composition of resources. Using GUDiv allows for prediction-based investigation of cascading indirect predation effects (ecology of fear) across multiple trophic levels, of feedbacks between functional trait composition of resource and consumer communities, and of effects of inter-individual differences among foragers on the diversity of resource communities.

Scale-dependent drivers of ungulate patch use along a temporal and spatial gradient of snow depth

2012 ◽  
Vol 90 (8) ◽  
pp. 972-983 ◽  
Author(s):  
J.C. Witt ◽  
C.R. Webster ◽  
R.E. Froese ◽  
T.D. Drummer ◽  
J.A. Vucetich
Keyword(s):  
Spatial Scales ◽  
Abiotic Factors ◽  
Landscape Composition ◽  
Trophic Levels ◽  
Spatial Gradient ◽  
Winter Habitat ◽  
Generalist Species ◽  
Patch Use ◽  
Cascading Effects ◽  
Decrease Use

Anthropogenic changes in landscape composition or configuration have the potential to increase the abundance of generalist species, often resulting in cascading effects on other trophic levels and ecosystem function. The selection or utilization of individual patches of habitat, however, may vary in both time and space, as a result of patch and landscape attributes as well as dynamic abiotic factors (i.e., snowfall). We hypothesized that the use of high-quality habitat would be most strongly influenced by snow at local scales and by composition and the configuration of the landscape at greater spatial scales. To test this, we examined white-tailed deer ( Odocoileus virginianus (Zimmermann, 1780)) selection of eastern hemlock ( Tsuga canadensis (L.) Carrière) patches as winter habitat over a 3-year period. Patch-level attributes were poor predictors of patch use in areas with strong gradients in abiotic factors relevant to the energetics of movement or forage acquisition. Additionally, heterogeneity in the greater landscape (3000 m radius buffer) served to increase use, while homogeneity appeared to decrease use. Our results suggest that interactions between deer migratory behavior, interannual variation in winter severity, and landscape context might provide spatial and temporal refugia for hemlock regeneration; a better understanding of which could aide conservation and restoration.

scholarly journals Increasing land use drives changes in plant phylogenetic diversity and prevalence of specialists

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e1740 ◽  
Author(s):  
Soraya Villalobos ◽  
Jana C. Vamosi
Keyword(s):  
Land Use ◽  
Mixed Forest ◽  
Functional Trait ◽  
Diagnostic Value ◽  
Trophic Levels ◽  
Cascading Effects ◽  
Human Land Use ◽  
Composition And Structure ◽  
Phylogenetic Composition ◽  
High Representation

Increased human land use has resulted in the increased homogenization of biodiversity between sites, yet we lack sufficient indicators to predict which species decline and the consequence of their potential loss on ecosystem services. We used comparative phylogenetic analysis to (1) characterize how increasing conversion of forest and grasslands to grazing pasturelands changes plant diversity and composition; (2) examine how changes in land use relate to declines in functional trait diversity; and (3) specifically investigate how these changes in plant composition affect the prevalence of zygomorphy and the possible consequences that these changes may have on pollinator functional groups. As predicted, we found that the conversion to grazing pasturelands negatively impacted species richness and phylogenetic composition. Clades with significantly more represented taxa in grasslands (GL) were genera with a high representation of agricultural weeds, while the composition was biased towards clades of subalpine herbaceous wildflowers in Mixed Forest (MF). Changes in community composition and structure had strong effects on the prevalence of zygomorphic species likely driven by nitrogen-fixing abilities of certain clades with zygomorphic flowers (e.g., Fabaceae). Land conversion can thus have unexpected impacts on trait distributions relevant for the functioning of the community in other capacities (e.g., cascading effects to other trophic levels (i.e., pollinators). Finally, the combination of traits represented by the current composition of species in GL and MF might enhance the diagnostic value of productivity and ecosystem processes in the most eroded ecosystems.

Functional trait diversity across trophic levels determines herbivore impact on plant community biomass

2015 ◽  
Vol 18 (12) ◽  
pp. 1346-1355 ◽  
Author(s):  
Hélène Deraison ◽  
Isabelle Badenhausser ◽  
Nicolas Loeuille ◽  
Christoph Scherber ◽  
Nicolas Gross
Keyword(s):  
Plant Community ◽  
Functional Trait ◽  
Trophic Levels ◽  
Community Biomass ◽  
Trait Diversity ◽  
Herbivore Impact ◽  
Functional Trait Diversity

scholarly journals Tree Diversity Reduces Fungal Endophyte Richness and Diversity in a Large-Scale Temperate Forest Experiment

Diversity ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 234 ◽  
Author(s):  
Eric A. Griffin ◽  
Joshua G. Harrison ◽  
Melissa K. McCormick ◽  
Karin T. Burghardt ◽  
John D. Parker
Keyword(s):  
Phylogenetic Diversity ◽  
Large Scale ◽  
High Throughput Sequencing ◽  
Spatial Scales ◽  
Fungal Endophytes ◽  
Fungal Endophyte ◽  
Tree Diversity ◽  
Trophic Levels ◽  
Community Diversity ◽  
And Function

Although decades of research have typically demonstrated a positive correlation between biodiversity of primary producers and associated trophic levels, the ecological drivers of this association are poorly understood. Recent evidence suggests that the plant microbiome, or the fungi and bacteria found on and inside plant hosts, may be cryptic yet important drivers of important processes, including primary production and trophic interactions. Here, using high-throughput sequencing, we characterized foliar fungal community diversity, composition, and function from 15 broadleaved tree species (N = 545) in a recently established, large-scale temperate tree diversity experiment using over 17,000 seedlings. Specifically, we tested whether increases in tree richness and phylogenetic diversity would increase fungal endophyte diversity (the “Diversity Begets Diversity” hypothesis), as well as alter community composition (the “Tree Diversity–Endophyte Community” hypothesis) and function (the “Tree Diversity–Endophyte Function” hypothesis) at different spatial scales. We demonstrated that increasing tree richness and phylogenetic diversity decreased fungal species and functional guild richness and diversity, including pathogens, saprotrophs, and parasites, within the first three years of a forest diversity experiment. These patterns were consistent at the neighborhood and tree plot scale. Our results suggest that fungal endophytes, unlike other trophic levels (e.g., herbivores as well as epiphytic bacteria), respond negatively to increasing plant diversity.

scholarly journals Contrasting responses of above- and belowground diversity to multiple components of land-use intensity

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Gaëtane Le Provost ◽  
Jan Thiele ◽  
Catrin Westphal ◽  
Caterina Penone ◽  
Eric Allan ◽  
...  
Keyword(s):  
Land Use ◽  
Forest Cover ◽  
Spatial Scales ◽  
Biodiversity Loss ◽  
Trophic Levels ◽  
Land Use Intensity ◽  
Trophic Groups ◽  
Multiple Components ◽  
Belowground Diversity ◽  
Landscape Level

AbstractLand-use intensification is a major driver of biodiversity loss. However, understanding how different components of land use drive biodiversity loss requires the investigation of multiple trophic levels across spatial scales. Using data from 150 agricultural grasslands in central Europe, we assess the influence of multiple components of local- and landscape-level land use on more than 4,000 above- and belowground taxa, spanning 20 trophic groups. Plot-level land-use intensity is strongly and negatively associated with aboveground trophic groups, but positively or not associated with belowground trophic groups. Meanwhile, both above- and belowground trophic groups respond to landscape-level land use, but to different drivers: aboveground diversity of grasslands is promoted by diverse surrounding land-cover, while belowground diversity is positively related to a high permanent forest cover in the surrounding landscape. These results highlight a role of landscape-level land use in shaping belowground communities, and suggest that revised agroecosystem management strategies are needed to conserve whole-ecosystem biodiversity.

scholarly journals Cascading effects of a top predator on intraspecific competition at intermediate and basal trophic levels

2018 ◽  
Vol 32 (9) ◽  
pp. 2241-2252 ◽  
Author(s):  
Catherine M. Matassa ◽  
Patrick J. Ewanchuk ◽  
Geoffrey C. Trussell
Keyword(s):  
Intraspecific Competition ◽  
Trophic Levels ◽  
Top Predator ◽  
Cascading Effects

Large mammals generate both top-down effects and extended trophic cascades on floral-visitor assemblages

2019 ◽  
Vol 35 (4) ◽  
pp. 185-198 ◽  
Author(s):  
Allison Louthan ◽  
Emily Valencia ◽  
Dino J. Martins ◽  
Travis Guy ◽  
Jacob Goheen ◽  
...  
Keyword(s):  
Trophic Cascade ◽  
Structural Equation ◽  
Trophic Cascades ◽  
Trophic Levels ◽  
Large Mammals ◽  
Top Down ◽  
Cascading Effects ◽  
Floral Visitor ◽  
Show Evidence ◽  
Floral Visitors

AbstractCascading effects of high trophic levels onto lower trophic levels have been documented in many ecosystems. Some studies also show evidence of extended trophic cascades, in which guilds dependent on lower trophic levels, but uninvolved in the trophic cascade themselves, are affected by the trophic cascade due to their dependence on lower trophic levels. Top-down effects of large mammals on plants could lead to a variety of extended trophic cascades on the many guilds dependent on plants, such as pollinators. In this study, floral-visitor and floral abundances and assemblages were quantified within a series of 1-ha manipulations of large-mammalian herbivore density in an African savanna. Top-down effects of large mammals on the composition of flowers available for floral visitors are first shown, using regressions of herbivore activity on metrics of floral and floral-visitor assemblages. An extended trophic cascade is also shown: the floral assemblage further altered the assemblage of floral visitors, according to a variety of approaches, including a structural equation modelling approach (model with an extended trophic cascade was supported over a model without, AICc weight = 0.984). Our study provides support for extended trophic cascades affecting floral visitors, suggesting that trophic cascades can have impacts throughout entire communities.

Zooplankton growth and survival differentially respond to interactive warming and acidification effects

2020 ◽  
Vol 42 (2) ◽  
pp. 189-202
Author(s):  
Jessica Garzke ◽  
Ulrich Sommer ◽  
Stefanie M H Ismar-Rebitz
Keyword(s):  
Ocean Acidification ◽  
Single Species ◽  
Functional Trait ◽  
Trophic Levels ◽  
Growth And Survival ◽  
Geographical Regions ◽  
Wide Range ◽  
Set Up ◽  
Taxonomic Groups ◽  
Zooplankton Growth

Abstract The copepod Acartia tonsa is a key component of a wide range of marine ecosystems, linking energy transfer from phytoplankton to higher trophic levels, and has a central role in productivity and biogeochemistry. The interaction of end-of-century global warming and ocean acidification scenarios with testing moderate temperature effects on a seminatural copepod community is needed to understand future community functioning. Here, we deployed a mesocosm experimental set-up with a full factorial design using two temperatures (13°C and 19°C) crossed with a pCO2 gradient ranging from ambient (550 μatm) to 3000 μatm. We used the natural bacteria, phyto- and microzooplankton species composition and biomass of the Kiel Bight and tested the response of A. tonsa development, carbon growth, mortality, size and condition. The tested traits were differently affected by the interaction of temperature and acidification. Ocean acidification increased development, carbon growth, size and mortality under the warming scenario of 19°C. At 13°C mortality rates decreased, while carbon growth, size and condition increased with acidification. We conclude from our experimental approach that a single species shows a variety of responses depending on the focal functional trait. Trait-specific mesozooplankton responses need to be further investigated and compared between geographical regions, seasons and taxonomic groups.

scholarly journals Comparative use of longline oysterbeds and adjacent tidal flats by waterbirds

2005 ◽  
Vol 15 (3) ◽  
pp. 237-255 ◽  
Author(s):  
LINDA M. CONNOLLY ◽  
MARK A. COLWELL
Keyword(s):  
Foraging Behaviour ◽  
Tidal Flats ◽  
Trophic Levels ◽  
Ardea Herodias ◽  
Interspecific Differences ◽  
Great Blue Heron ◽  
Species Abundances ◽  
Underlying Causes ◽  
Intertidal Habitats ◽  
And Control

Commercial oyster Crassostrea spp. cultivation in intertidal habitats may degrade foraging habitat of waterbirds. Consequently, we compared species abundances, community similarity and diversity of waterbirds using longline oyster culture beds and adjacent control plots on tidal flats of Humboldt Bay, California. Abundances of most species differed significantly between treatments, with seven of 13 shorebirds Charadriiformes and three of four wading birds Ciconiiformes more abundant on longline plots. By contrast, Black-bellied Plover Pluvialis squatarola were more abundant on control plots. Marbled Godwit Limosa fedoa, Long-billed Curlew Numenius americanus and Dunlin Calidris alpina showed mixed results depending on location and Great Blue Heron Ardea herodias were more abundant only on one control plot. Community composition was similar on longline and control plots, although diversity (H′) was greater on longline plots. Varying species' responses to longline techniques may have been associated with interspecific differences in diet and foraging behaviour, and the impacts of longlines and oyster-harvesting on prey distribution. Overall, longlines did not negatively affect the foraging behaviour of most species, but the underlying causes for increased bird use may lead to impacts on other trophic levels and over a longer temporal scale.

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