scholarly journals Cushion plants are foundation species with positive effects extending to higher trophic levels

Ecosphere ◽  
2012 ◽  
Vol 3 (11) ◽  
pp. art96 ◽  
Author(s):  
Anya M. Reid ◽  
Christopher J. Lortie
Keyword(s):  
Trophic Levels ◽  
Foundation Species ◽  
Cushion Plants ◽  
Positive Effects

scholarly journals Cushion plants act as facilitators for soil microarthropods in high alpine Sweden

2021 ◽  
Author(s):  
Peter Ľuptáčik ◽  
Peter Čuchta ◽  
Patrícia Jakšová ◽  
Dana Miklisová ◽  
Ľubomír Kováč ◽  
...  
Keyword(s):  
Species Richness ◽  
Diversity Index ◽  
Elevation Gradient ◽  
Oribatid Mite ◽  
Soil Samples ◽  
Trophic Levels ◽  
Soil Microarthropods ◽  
Cushion Plant ◽  
Cushion Plants ◽  
Positive Effects

AbstractCushion plants can have positive impacts on plant richness in severe environments and possibly across trophic levels on arthropods, an under-studied topic. This study examined whether soil communities under cushions have higher richness and abundance of soil microarthropods than adjacent non-cushion vegetation, and whether differences in collembolan and mite abundance and species richness between cushions and adjacent vegetation increase with elevation. Paired soil samples were taken under cushions of Silene acaulis along the elevation gradient (1000, 1100, 1200, 1300, 1400 m a.s.l.), under cushions of Diapensia lapponica on the exposed ridge above the treeline (1000 m a.s.l.), and under adjacent non-cushion plant vegetation. In total, 5853 individuals of collembolans (n = 1705) and mites (n = 4148) were obtained from soil samples and identified to order/species level. S. acaulis cushions had a positive effect on species richness and abundance of collembolans, with richness effects from 1100 m a.s.l. upwards. Oribatid mite richness and abundance were also higher under cushions compared with adjacent vegetation. Species richness of collembolans and oribatids declined with increasing elevation from 1200 m a.s.l. Collembolan abundance peaked at mid-elevation (1200 m a.s.l.) under cushions and adjacent vegetation, while oribatid mite abundance peaked at 1300 m a.s.l. under both vegetation types. D. lapponica cushions on the exposed ridge had significant positive effects on species richness, abundance and diversity index of collembolans, and abundance of oribatids. Cushion plants play an important role in supporting the biodiversity of soil fauna in severe alpine environments, with the positive effects of cushion plants increasing with environmental severity.

Effects of Two Cultivated Brassica spp. on the Development and Performance of Diadegma semiclausum (Hymenoptera: Ichneumonidae) and Cotesia vestalis (Hymenoptera: Braconidae) Parasitizing Plutella xylostella (Lepidoptera: Plutellidae) in Kenya

2019 ◽  
Vol 112 (5) ◽  
pp. 2094-2102 ◽  
Author(s):  
Ruth Kahuthia-Gathu ◽  
Stephen T O Othim
Keyword(s):  
Host Plant ◽  
Plutella Xylostella ◽  
Development Time ◽  
Trophic Levels ◽  
Pupal Weight ◽  
Vegetable Production ◽  
Diadegma Semiclausum ◽  
Cotesia Vestalis ◽  
Positive Effects ◽  
And Performance

AbstractThe diamondback moth (DBM), Plutella xylostella L., is the most destructive pest affecting vegetable production in Kenya and around the world. Parasitoids have shown promising results in lowering the pest populations and damage caused by DBM. However, variations in host plant quality have been reported to have bottom-up effects up to the third and fourth trophic levels. We assessed the effects of two cultivated Brassica varieties (cabbage, Brassica oleracea var. capitata L. cultivar ‘Gloria F1’ and kale, B. oleracea var. acephala L. cultivar ‘Thousand headed’) on the development and performance of the specialist pest P. xylostella and two exotic parasitoids Diadegma semiclausum (Hellen) and Cotesia vestalis (Haliday). The exposed larval period of DBM took about 1.5 d longer on kale than cabbage and the total immature development time of both females and males was significantly longer on kale than cabbage. Higher pupal weight and higher fecundity were recorded on DBM fed on kale. Development time of D. semiclausum and C. vestalis was not affected by the host crop as was the parasitism rate of D. semiclausum. Heavier male pupae and larger adults of D. semiclausum, as well as more fecund adults of C. vestalis, were obtained from hosts fed on cabbage. Larger adults of C. vestalis were obtained from herbivores fed on kale. These results show potentially positive effects of host plant allelochemicals that are detrimental to herbivores while promoting parasitoid development and performance, which can be harnessed for the control of DBM.

scholarly journals Mesopredator suppression by an apex predator alleviates the risk of predation perceived by small prey

2015 ◽  
Vol 282 (1802) ◽  
pp. 20142870 ◽  
Author(s):  
Christopher E. Gordon ◽  
Anna Feit ◽  
Jennifer Grüber ◽  
Mike Letnic
Keyword(s):  
Population Level ◽  
Trophic Levels ◽  
Foraging Efficiency ◽  
Apex Predator ◽  
Apex Predators ◽  
Small Prey ◽  
Positive Effects ◽  
Risk Of Predation ◽  
Habitat Breadth ◽  
Access To Food

Predators can impact their prey via consumptive effects that occur through direct killing, and via non-consumptive effects that arise when the behaviour and phenotypes of prey shift in response to the risk of predation. Although predators' consumptive effects can have cascading population-level effects on species at lower trophic levels there is less evidence that predators' non-consumptive effects propagate through ecosystems. Here we provide evidence that suppression of abundance and activity of a mesopredator (the feral cat) by an apex predator (the dingo) has positive effects on both abundance and foraging efficiency of a desert rodent. Then by manipulating predators' access to food patches we further the idea that apex predators provide small prey with refuge from predation by showing that rodents increased their habitat breadth and use of ‘risky′ food patches where an apex predator was common but mesopredators rare. Our study suggests that apex predators' suppressive effects on mesopredators extend to alleviate both mesopredators' consumptive and non-consumptive effects on prey.

scholarly journals Species Diversity Associated with Foundation Species in Temperate and Tropical Forests

Forests ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 128 ◽  
Author(s):  
Aaron Ellison ◽  
Hannah Buckley ◽  
Bradley Case ◽  
Dairon Cardenas ◽  
Álvaro Duque ◽  
...  
Keyword(s):  
Tropical Forests ◽  
Beta Diversity ◽  
Spatial Association ◽  
Western Hemisphere ◽  
Foundation Species ◽  
Ecological Communities ◽  
Size Frequency Distribution ◽  
Positive Effects ◽  
Size Frequency ◽  
Species Groups

Foundation species define and structure ecological communities but are difficult to identify before they are declining. Yet, their defining role in ecosystems suggests they should be a high priority for protection and management while they are still common and abundant. We used comparative analyses of six large forest dynamics plots spanning a temperate-to-tropical gradient in the Western Hemisphere to identify statistical “fingerprints” of potential foundation species based on their size-frequency and abundance-diameter distributions, and their spatial association with five measures of diversity of associated woody plant species. Potential foundation species are outliers from the common “reverse-J” size-frequency distribution, and have negative effects on alpha diversity and positive effects on beta diversity at most spatial lags and directions. Potential foundation species also are more likely in temperate forests, but foundational species groups may occur in tropical forests. As foundation species (or species groups) decline, associated landscape-scale (beta) diversity is likely to decline along with them. Preservation of this component of biodiversity may be the most important consequence of protecting foundation species while they are still common.

scholarly journals Characteristics of the Biochemical Composition and Bioavailability of Phytoplankton-Derived Particulate Organic Matter in the Chukchi Sea, Arctic

Water ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2355
Author(s):  
Bo Kim ◽  
Jinyoung Jung ◽  
Youngju Lee ◽  
Kyoung-Ho Cho ◽  
Jong-Ku Gal ◽  
...  
Keyword(s):  
Organic Matter ◽  
Enzymatic Hydrolysis ◽  
Particulate Organic Matter ◽  
Biochemical Composition ◽  
Chukchi Sea ◽  
Total Concentration ◽  
Trophic Levels ◽  
Food Utilization ◽  
Positive Effects ◽  
Bioavailable Fraction

Analysis of the biochemical composition (carbohydrates, CHO; proteins, PRT; lipids, LIP) of particulate organic matter (POM, mainly phytoplankton) is used to assess trophic states, and the quantity of food material is generally assessed to determine bioavailability; however, bioavailability is reduced or changed by enzymatic hydrolysis. Here, we investigated the current trophic state and bioavailability of phytoplankton in the Chukchi Sea (including the Chukchi Borderland) during the summer of 2017. Based on a cluster analysis, our 12 stations were divided into three groups: the southern, middle, and northern parts of the Chukchi Sea. A principal component analysis (PCA) revealed that relatively nutrient-rich and high-temperature waters in the southern part of the Chukchi Sea enhanced the microphytoplankton biomass, while picophytoplankton were linked to a high contribution of meltwater derived from sea ice melting in the northern part of the sea. The total PRT accounted for 41.8% (±7.5%) of the POM in the southern part of the sea, and this contribution was higher than those in the middle (26.5 ± 7.5%) and northern (26.5 ± 10.6%) parts, whereas the CHO accounted for more than half of the total POM in the northern parts. As determined by enzymatic hydrolysis, LIP were more rapidly mineralized in the southern part of the Chukchi Sea, whereas CHO were largely used as source of energy for higher trophic levels in the northern part of the Chukchi Sea. Specifically, the bioavailable fraction of POM in the northern part of the Chukchi Sea was higher than it was in the other parts. The findings indicate that increasing meltwater and a low nutrient supply lead to smaller cell sizes of phytoplankton and their taxa (flagellate and green algae) with more CHO and a negative effect on the total concentration of POM. However, in terms of bioavailability (food utilization), which determines the rate at which digested food is used by consumers, potentially available food could have positive effects on ecosystem functioning.

scholarly journals Tree species richness attenuates the positive relationship between mutualistic ant–hemipteran interactions and leaf chewer herbivory

2017 ◽  
Vol 284 (1862) ◽  
pp. 20171489 ◽  
Author(s):  
Andreas Schuldt ◽  
Felix Fornoff ◽  
Helge Bruelheide ◽  
Alexandra-Maria Klein ◽  
Michael Staab
Keyword(s):  
Species Richness ◽  
Tree Species ◽  
Positive Relationship ◽  
Biodiversity Loss ◽  
Trophic Levels ◽  
Ecosystem Functions ◽  
Positive Effects ◽  
Tree Species Richness ◽  
Species Richness Gradient ◽  
Herbivore Communities

Interactions across trophic levels influence plant diversity effects on ecosystem functions, but the complexity of these interactions remains poorly explored. For example, the interplay between different interactions (e.g. mutualism, predation) might be an important moderator of biodiversity–ecosystem function relationships. We tested for relationships between trophobioses (facultative ant–hemipteran mutualism) and leaf chewer herbivory in a subtropical forest biodiversity experiment. We analysed trophobiosis and herbivory data of more than 10 000 trees along a tree species richness gradient. Against expectations, chewing damage was higher on trees with trophobioses. However, the net positive relationship between trophobioses and overall herbivory depended on tree species richness, being most pronounced at low richness. Our results point to indirect, positive effects of ant-tended sap suckers on leaf chewers, potentially by altering plant defences. Direct antagonistic relationships of trophobiotic ants and leaf-chewing herbivores—frequently reported to drive community-wide effects of trophobioses in other ecosystems—seemed less relevant. However, antagonistic interactions likely contributed to the attenuating effect of tree species richness, because trophobiotic ant and herbivore communities changed from monocultures to species-rich mixtures. Our findings, therefore, suggest that biodiversity loss might lead to complex changes in higher trophic level effects on ecosystem functions, mediated by both trophic and non-trophic interactions.

scholarly journals Cushion plants act as facilitators for soil microarthropods in high alpine Sweden

2020 ◽  
Author(s):  
Peter Ľuptáčik ◽  
Peter Čuchta ◽  
Patrícia Jakšová ◽  
Dana Miklisová ◽  
Ľubomír Kováč ◽  
...  
Keyword(s):  
Species Richness ◽  
Elevation Gradient ◽  
Oribatid Mite ◽  
Trophic Levels ◽  
Soil Microarthropods ◽  
Cushion Plant ◽  
Cushion Plants ◽  
Diapensia Lapponica ◽  
Silene Acaulis ◽  
Positive Effect

1.Cushion plants can have positive impacts on plant richness in severe environments and possibly across trophic levels on arthropods, an under-studied topic. 2.This study examined whether soil communities under cushions of Silene acaulis and Diapensia lapponica have higher richness and abundance of soil microarthropods (Acari, Collembola) than adjacent non-cushion vegetation; and whether differences in collembolan and mite abundance and species richness between S. acaulis cushions and adjacent vegetation increase with elevation.3.In total, 5199 individuals of Collembola (n=1392) and mites (n=3807) were identified to order/species level in samples along an elevation transect (1000, 1100, 1200, 1300, and 1400 m a.s.l.), and an exposed ridge above the treeline (1000 m a.s.l.) in northern Sweden. Paired soil samples were taken within cushions of Silene acaulis (along the elevation gradient) and Diapensia lapponica (on the exposed ridge) and adjacent non-cushion plant vegetation. 4.Silene acaulis had a positive effect on species richness and abundance of Collembola, with richness effects from 1100 m a.s.l. upwards. Oribatid mite abundance and richness were also higher in S. acaulis compared with adjacent vegetation. 5.Species richness of Collembola and Oribatida declined with increasing elevation from 1200 m a.s.l. Collembola abundance peaked at mid-elevation (1200 m a.s.l.) in both S. acaulis and adjacent vegetation, while oribatid mite abundance peaked at 1300 m a.s.l. in both vegetation types. 6.Cushions of D. lapponica on the exposed ridge had a significant positive effect on species richness, abundance and diversity of Collembola, and abundance of Oribatida. 7.Alpine cushion plants play an important role in supporting biodiversity of soil fauna in severe alpine environments, with the positive effect of cushion plants increasing with environment severity.

scholarly journals Phytoplankton Diversity Effect on Ecosystem Functioning in a Coastal Upwelling System

2020 ◽  
Vol 7 ◽  
Author(s):  
Jaime Otero ◽  
Xosé Antón Álvarez-Salgado ◽  
Antonio Bode
Keyword(s):  
Functional Diversity ◽  
Ecosystem Functioning ◽  
Coastal Upwelling ◽  
Explanatory Power ◽  
Taxonomic Diversity ◽  
Least Square ◽  
Trophic Levels ◽  
Phytoplankton Diversity ◽  
Positive Effects ◽  
Upwelling System

Species composition plays a key role in ecosystem functioning. Theoretical, experimental and field studies show positive effects of biodiversity on ecosystem processes. However, this link can differ between taxonomic and functional diversity components and also across trophic levels. These relationships have been hardly studied in planktonic communities of coastal upwelling systems. Using a 28-year time series of phytoplankton and zooplankton assemblages, we examined the effects of phytoplankton diversity on resource use efficiency (RUE, ratio of biomass to limiting resource) at the two trophic levels in the Galician upwelling system (NW Iberian peninsula). By fitting generalized least square models, we show that phytoplankton diversity was the best predictor for RUE across planktonic trophic levels. This link varied depending on the biodiversity component considered: while the effect of phytoplankton richness on RUE was positive for phytoplankton RUE and negative for zooplankton RUE, phytoplankton evenness effect was negative for phytoplankton RUE and positive for zooplankton RUE. Overall, taxonomic diversity had higher explanatory power than functional diversity, and variability in phytoplankton and zooplankton RUE decreased with increasing phytoplankton taxonomic diversity. Phytoplankton used resources more efficiently in warmer waters and at greater upwelling intensity, although these effects were not as strong as those for biodiversity. These results suggest that phytoplankton species numbers in highly dynamic upwelling systems are important for maintaining the planktonic biomass production leading us to hypothesize the relevance of complementarity effects. However, we further postulate that a selection effect may operate also because assemblages with low evenness were dominated by diatoms with specific functional traits increasing their ability to exploit resources more efficiently.

scholarly journals Climate Change Increases Susceptibility to Grazers in a Foundation Seaweed

2021 ◽  
Vol 8 ◽  
Author(s):  
Alexandra Kinnby ◽  
Gunilla B. Toth ◽  
Henrik Pavia
Keyword(s):  
Climate Change ◽  
C:N Ratio ◽  
Brown Seaweed ◽  
Coastal Ecosystems ◽  
Chemical Defenses ◽  
Foundation Species ◽  
Interactive Effects ◽  
Physical Factors ◽  
Positive Effects ◽  
Phlorotannin Content

Climate change leads to multiple effects caused by simultaneous shifts in several physical factors which will interact with species and ecosystems in complex ways. In marine systems the effects of climate change include altered salinity, increased temperature, and elevated pCO2 which are currently affecting and will continue to affect marine species and ecosystems. Seaweeds are primary producers and foundation species in coastal ecosystems, which are particularly vulnerable to climate change. The brown seaweed Fucus vesiculosus (bladderwrack) is an important foundation species in nearshore ecosystems throughout its natural range in the North Atlantic Ocean and the Baltic Sea. This study investigates how individual and interactive effects of temperature, salinity, and pCO2 affect F. vesiculosus, using a fully crossed experimental design. We assessed the effects on F. vesiculosus in terms of growth, biochemical composition (phlorotannin content, C:N ratio, and ∂13C), and susceptibility to the specialized grazer Littorina obtusata. We observed that elevated pCO2 had a positive effect on seaweed growth in ambient temperature, but not in elevated temperature, while growth increased in low salinity at ambient but not high temperature, regardless of pCO2-level. In parallel to the statistically significant, but relatively small, positive effects on F. vesiculosus growth, we found that the seaweeds became much more susceptible to grazing in elevated pCO2 and reduced salinity, regardless of temperature. Furthermore, the ability of the seaweeds to induce chemical defenses (phlorotannins) was strongly reduced by all the climate stressors. Seaweeds exposed to ambient conditions more than doubled their phlorotannin content in the presence of grazers, while seaweeds exposed to any single or combined stress conditions showed only minor increases in phlorotannin content, or none at all. Despite the minor positive effects on seaweed growth, the results of this study imply that climate change can strongly affect the ability of fucoid seaweeds to induce chemical defenses and increase their susceptibility to grazers. This will likely lead to widespread consequences under future climate conditions, considering the important role of F. vesiculosus and other fucoids in many coastal ecosystems.

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