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.

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 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 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.

Beavers and lilies: selective herbivory and adaptive foraging behaviour

2013 ◽  
Vol 59 (2) ◽  
pp. 224-232 ◽  
Author(s):  
A. Law ◽  
N. Bunnefeld ◽  
N. J. Willby
Keyword(s):  
Foraging Behaviour ◽  
Selective Herbivory ◽  
Adaptive Foraging

Effects of juvenile fish predation (Cyprinus carpio L.) on the composition and diversity of free-living freshwater nematode assemblages

Nematology ◽  
2016 ◽  
Vol 18 (1) ◽  
pp. 39-52 ◽  
Author(s):  
Sebastian Weber ◽  
Walter Traunspurger
Keyword(s):  
Species Composition ◽  
Cyprinus Carpio ◽  
Juvenile Fish ◽  
Natural Habitat ◽  
Fish Predation ◽  
Trophic Levels ◽  
Free Living ◽  
Food Web Ecology ◽  
Freshwater Pond ◽  
Predation Effects

Free-living nematodes are well recognised as an abundant and ubiquitous component of meiobenthic communities, where they serve as a link between microbial production and higher trophic levels. However, the effect of fish predation on nematode assemblages is almost unknown. In this study, the predation effects of the benthivorous juvenile carp (Cyprinus carpio) on nematode abundance, biomass, diversity and species composition in the littoral zone of a natural freshwater pond were examined over 310 days using field enclosures and exclosures. Fish predation altered the abundance and biomass of nematodes, and especially of the dominant species Tobrilus gracilis, Eumonhystera filiformis and Monhystera paludicola/stagnalis. Species richness and species composition, but not the diversity and feeding type of nematode assemblages, were affected by fish predation. Our study provides insights into the food-web ecology of lakes and the first evidence of freshwater fish predation effects on nematode assemblages in a natural habitat.

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