scholarly journals Trophic downgrading decreases species asynchrony and community stability regardless of climate warming

2021 ◽  
Author(s):  
Felipe Rezende ◽  
Pablo Antiqueira ◽  
Owen Petchey ◽  
Luiz Velho ◽  
Luzia Rodrigues ◽  
...  
Keyword(s):  
Climate Warming ◽  
Environmental Changes ◽  
Temporal Stability ◽  
Biodiversity Loss ◽  
Trophic Levels ◽  
Community Stability ◽  
Top Predator ◽  
Top Predators ◽  
Consequent Reduction ◽  
Current Scenario

Theory and some evidence suggest that biodiversity promotes stability. However, evidence of how trophic interactions and environmental changes modulate this relationship in multitrophic communities is lacking. Given the current scenario of biodiversity loss and climate changes, where top predators are disproportionately more affected, filling these knowledge gaps is crucial. We simulated climate warming and top predator loss in natural microcosms to investigate their direct and indirect effects on temporal stability of microbial communites. We also investigated the role of underlying stabilizing mechanisms on community stability. Community stability was insensitive to warming, but indirectly decreased due to top predator loss via increased mesopredator abundance and consequent reduction of species asynchrony and stability. The magnitude of destabilizing effects differed among trophic levels, being disproportionally higher at lower trophic levels (e.g. producers). Our study unravels major patterns and causal mechanisms by which trophic downgrading destabilizes large food webs, regardless of climate warming scenarios.

Functional diversity alters the effects of a pulse perturbation on the dynamics of tritrophic food webs

2021 ◽  
Author(s):  
Ruben Ceulemans ◽  
Laurie Anne Myriam Wojcik ◽  
Ursula Gaedke
Keyword(s):  
Food Web ◽  
Food Webs ◽  
Functional Diversity ◽  
Feedback Loop ◽  
Environmental Changes ◽  
Biodiversity Loss ◽  
Trophic Levels ◽  
Nutrient Pulse ◽  
Trade Offs ◽  
Food Web Model

Biodiversity decline causes a loss of functional diversity, which threatens ecosystems through a dangerous feedback loop: this loss may hamper ecosystems' ability to buffer environmental changes, leading to further biodiversity losses. In this context, the increasing frequency of climate and human-induced excessive loading of nutrients causes major problems in aquatic systems. Previous studies investigating how functional diversity influences the response of food webs to disturbances have mainly considered systems with at most two functionally diverse trophic levels. Here, we investigate the effects of a nutrient pulse on the resistance, resilience and elasticity of a tritrophic---and thus more realistic---plankton food web model depending on its functional diversity. We compare a non-adaptive food chain with no diversity to a highly diverse food web with three adaptive trophic levels. The species fitness differences are balanced through trade-offs between defense/growth rate for prey and selectivity/half-saturation constant for predators. We showed that the resistance, resilience and elasticity of tritrophic food webs decreased with larger perturbation sizes and depended on the state of the system when the perturbation occured. Importantly, we found that a more diverse food web was generally more resistant, resilient, and elastic. Particularly, functional diversity dampened the probability of a regime shift towards a non-desirable alternative state. In addition, despite the complex influence of the shape and type of the dynamical attractors, the basal-intermediate interaction determined the robustness against a nutrient pulse. This relationship was strongly influenced by the diversity present and the third trophic level. Overall, using a food web model of realistic complexity, this study confirms the destructive potential of the positive feedback loop between biodiversity loss and robustness, by uncovering mechanisms leading to a decrease in resistance, resilience and elasticity as functional diversity declines.

scholarly journals Trophic cascades alter eco-evolutionary dynamics and body size evolution

2020 ◽  
Vol 287 (1938) ◽  
pp. 20200526
Author(s):  
Thomas M. Luhring ◽  
John P. DeLong
Keyword(s):  
Body Mass ◽  
Trophic Level ◽  
Evolutionary Dynamics ◽  
Trophic Cascades ◽  
Trophic Levels ◽  
Chain Model ◽  
Top Predator ◽  
Predator Prey ◽  
Top Predators ◽  
Time Changes

Trait evolution in predator–prey systems can feed back to the dynamics of interacting species as well as cascade to impact the dynamics of indirectly linked species (eco-evolutionary trophic cascades; EETCs). A key mediator of trophic cascades is body mass, as it both strongly influences and evolves in response to predator–prey interactions. Here, we use Gillespie eco-evolutionary models to explore EETCs resulting from top predator loss and mediated by body mass evolution. Our four-trophic-level food chain model uses allometric scaling to link body mass to different functions (ecological pleiotropy) and is realistically parameterized from the FORAGE database to mimic the parameter space of a typical freshwater system. To track real-time changes in selective pressures, we also calculated fitness gradients for each trophic level. As predicted, top predator loss generated alternating shifts in abundance across trophic levels, and, depending on the nature and strength in changes to fitness gradients, also altered trajectories of body mass evolution. Although more distantly linked, changes in the abundance of top predators still affected the eco-evolutionary dynamics of the basal producers, in part because of their relatively short generation times. Overall, our results suggest that impacts on top predators can set off transient EETCs with the potential for widespread indirect impacts on food webs.

scholarly journals Plant and soil biodiversity have non-substitutable stabilizing effects on biomass production

2021 ◽  
Author(s):  
Gaowen Yang ◽  
Masahiro Ryo ◽  
Julien Roy ◽  
Stefan Hempel ◽  
Matthias Rillig
Keyword(s):  
Biomass Production ◽  
Plant Diversity ◽  
Plant Biomass ◽  
Temporal Stability ◽  
Terrestrial Ecosystem ◽  
Biodiversity Loss ◽  
Trophic Levels ◽  
Plant Functional Groups ◽  
Soil Biodiversity ◽  
Simulated Precipitation

The stability of plant biomass production in the face of environmental change is fundamental for maintaining terrestrial ecosystem functioning, as plant biomass is the ultimate source of energy for nearly all life forms. However, most studies have focused on the stabilizing effect of plant diversity, neglecting the effect of soil biodiversity, the largest reservoirs of biodiversity on Earth. Here we investigated the effects of plant and soil biodiversity on the temporal stability of biomass production under varying simulated precipitation in grassland microcosms. Soil biodiversity loss reduced temporal stability by suppressing asynchronous responses of plant functional groups. Greater plant diversity, especially in terms of functional diversity, promoted temporal stability, but this effect was independent of soil biodiversity loss. Moreover, multitrophic biodiversity, plant and soil biodiversity combined, was positively associated with temporal stability. Our study highlights the importance of maintaining the biodiversity of multiple trophic levels for sustainable biomass production.

scholarly journals Asynchrony Drives Plant and Animal Community Stability in Mediterranean Coastal Dunes

2021 ◽  
Vol 11 (13) ◽  
pp. 6214
Author(s):  
Tania L.F. Bird ◽  
Pua Bar (Kutiel) ◽  
Elli Groner ◽  
Amos Bouskila
Keyword(s):  
Species Interactions ◽  
Plant Cover ◽  
Temporal Stability ◽  
Coastal Dunes ◽  
Biodiversity Loss ◽  
Community Stability ◽  
Perennial Plant ◽  
Strong Positive Relationship ◽  
Long Term Ecological Research ◽  
Animal Community

Substantial evidence now suggests that a positive diversity–stability relationship exists. Yet few studies examine the facets of biodiversity that contribute to this relationship, and empirical research is predominantly conducted on grassland communities under controlled conditions. We investigate the roles of species richness, environmental condition (vegetation cover), asynchrony, and weighted population stability in driving community stability across multiple taxa. We used data from a Long-term Ecological Research project to investigate temporal stability of annual plants, beetles, reptiles, and rodents in Nizzanim Coastal Sand Dune Nature Reserve in Israel. All four taxa had a strong positive relationship between asynchrony and community stability. Only rodents showed a positive richness–stability relationship. Perennial plant cover had a significant relationship with community stability for three taxa, but the direction of the correlation varied. Asynchrony had a stronger relationship with perennial plant cover than it did with richness for both plants and beetles. We suggest that community stability is driven by asynchrony for flora as well as fauna. Stability appears to be determined by species’ interactions and their responses to the environment, and not always by diversity. This has important consequences for understanding the effects of environmental degradation on ecosystem stability and productivity, which have destabilizing consequences beyond biodiversity loss.

Trophic Cascades in Grasslands

2018 ◽  
Author(s):  
Brian J. Wilsey
Keyword(s):  
Indirect Effects ◽  
Prey Species ◽  
Trophic Levels ◽  
Herbaceous Plant ◽  
Direct Effects ◽  
Temperate Grasslands ◽  
Cascading Effect ◽  
Top Predators ◽  
Invertebrate Predators ◽  
Ecology Of Fear

Top predators have effects that can ‘cascade down’ on lower trophic levels. Because of this cascading effect, it matters how many trophic levels are present. Predators are either ‘sit and wait’ or ‘active’. Wolves are top predators in temperate grasslands and can alter species composition of smaller-sized predators, prey, and woody and herbaceous plant species, either through direct effects or indirect effects (‘Ecology of Fear’). In human derived grasslands, invertebrate predators fill a similar ecological role as wolves. Migrating populations of herbivores tend to be more limited by food than non-migratory populations. The phenology and synchrony of births vary among prey species in a way that is consistent with an adaptation to predation. Precocious species have highly synchronous birth dates to satiate predators. Non-precocious species (‘hiders’) have asynchronous births. Results from studies that manipulate both predators and food support the hypothesis that bottom-up and top-down effects interact.

scholarly journals Fine-scale structures as spots of increased fish concentration in the open ocean

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Alberto Baudena ◽  
Enrico Ser-Giacomi ◽  
Donatella D’Onofrio ◽  
Xavier Capet ◽  
Cedric Cotté ◽  
...  
Keyword(s):  
Coherent Structures ◽  
Trophic Levels ◽  
Fish Distribution ◽  
Lagrangian Coherent Structures ◽  
Mesopelagic Fish ◽  
Fine Scale ◽  
Conservation Policies ◽  
Top Predators ◽  
Frontal Zones ◽  
Spatio Temporal

AbstractOceanic frontal zones have been shown to deeply influence the distribution of primary producers and, at the other extreme of the trophic web, top predators. However, the relationship between these structures and intermediate trophic levels is much more obscure. In this paper we address this knowledge gap by comparing acoustic measurements of mesopelagic fish concentrations to satellite-derived fine-scale Lagrangian Coherent Structures in the Indian sector of the Southern Ocean. First, we demonstrate that higher fish concentrations occur more frequently in correspondence with strong Lagrangian Coherent Structures. Secondly, we illustrate that, while increased fish densities are more likely to be observed over these structures, the presence of a fine-scale feature does not imply a concomitant fish accumulation, as other factors affect fish distribution. Thirdly, we show that, when only chlorophyll-rich waters are considered, front intensity modulates significantly more the local fish concentration. Finally, we discuss a model representing fish movement along Lagrangian features, specifically built for mid-trophic levels. Its results, obtained with realistic parameters, are qualitatively consistent with the observations and the spatio-temporal scales analysed. Overall, these findings may help to integrate intermediate trophic levels in trophic models, which can ultimately support management and conservation policies.

scholarly journals Climate change drives mountain butterflies towards the summits

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Dennis Rödder ◽  
Thomas Schmitt ◽  
Patrick Gros ◽  
Werner Ulrich ◽  
Jan Christian Habel
Keyword(s):  
Climate Change ◽  
Life History ◽  
Climate Warming ◽  
Environmental Changes ◽  
Range Shifts ◽  
Solar Irradiation ◽  
High Mountain ◽  
Detailed Knowledge ◽  
Annual Range

AbstractClimate change impacts biodiversity and is driving range shifts of species and populations across the globe. To understand the effects of climate warming on biota, long-term observations of the occurrence of species and detailed knowledge on their ecology and life-history is crucial. Mountain species particularly suffer under climate warming and often respond to environmental changes by altitudinal range shifts. We assessed long-term distribution trends of mountain butterflies across the eastern Alps and calculated species’ specific annual range shifts based on field observations and species distribution models, counterbalancing the potential drawbacks of both approaches. We also compiled details on the ecology, behaviour and life-history, and the climate niche of each species assessed. We found that the highest altitudinal maxima were observed recently in the majority of cases, while the lowest altitudes of observations were recorded before 1980. Mobile and generalist species with a broad ecological amplitude tended to move uphill more than specialist and sedentary species. As main drivers we identified climatic conditions and topographic variables, such as insolation and solar irradiation. This study provides important evidence for responses of high mountain taxa to rapid climate change. Our study underlines the advantage of combining historical surveys and museum collection data with cutting-edge analyses.

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 Premises of Sustainable Development Concept Occurence

2019 ◽  
Vol 24 (1) ◽  
pp. 45-53
Author(s):  
Elisabeta-Emilia Halmaghi ◽  
Mihai-Marcel Neag
Keyword(s):  
Sustainable Development ◽  
Animal Species ◽  
Environmental Changes ◽  
Environmental Issues ◽  
Biodiversity Loss ◽  
Point Of View ◽  
Pesticide Use ◽  
Political Debate ◽  
Toxic Product ◽  
Difficult Issue

Abstract It has long been considered that the environment can withstand all the pressure exerted by human activities on it: extensive agriculture, pesticide use, strong industrialization, noxious gas emissions into the atmosphere, toxic product discharge into lakes, rivers, seas and oceans, massive deforestation to obtain new areas for housing or agriculture. The result was environmental and soil degradation, increased water and/or air pollution, climate change, biodiversity loss, the disappearance of plant and/or animal species, the depletion of some natural resources. These environmental changes have begun to be studied by specialists in the field, who have raised a flag to irreversible environmental changes. The concept of “sustainable development” arose at a time when environmental issues were at the heart of political debate: sustainable development is seen as a complex and difficult issue to solve because there is a diversity of interests of different states. International agreements and cooperation from the point of view of globalization and economic harmonization have also had as their object the issues of sustainable development, by launching the attempt to reconcile the economy with the environment.

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
Sign in / Sign up

Export Citation Format

Share Document