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One central challenge for humanity is to mitigate and adapt to an ongoing climate and biodiversity crisis while providing resources to a growing human population. Ecological intensification aims to maximise crop productivity while minimizing impacts on the environment, especially by using biodiversity to improve ecosystem functions and services. Many ecological intensification measures are based on trophic interactions between organisms (e.g. pollination, biocontrol). Here, we investigate how research on multitrophic effects of biodiversity on ecosystem functioning could advance the application of ecological intensification measures in agriculture and forestry. We review previous studies and use qualitative analyses of the literature to test how important variables such as land-use parameters or habitat complexity affect multitrophic diversity, ecosystem functions and multitrophic biodiversity–ecosystem functioning relationships. We found that positive effects of biodiversity on ecosystem functions are prevalent in production systems, largely across ecosystem function dimensions, trophic levels, study methodologies and different ecosystem functions, however, with certain context-dependencies. We also found strong impacts of land use and management on multitrophic biodiversity and ecosystem functions. We detected knowledge gaps in terms of data from underrepresented geographical areas, production systems, organism groups and functional diversity measurements. Additionally, we identified several aspects that require more attention in the future, such as trade-offs between multiple functions, temporal dynamics, effects of climate change, the spatial scale of the measures and their implementation. This information will be vital to ensure that agricultural and forest landscapes produce resources for humanity sustainably within the environmental limits of the planet.

The dynamics of interactions amongst natural enemies are central to the investigation of insect pest ecology. Ternary and quaternary interactions between parasitoids and predators in the presence of entomophagous organisms are yet to be comprehensively explored. We investigated the performance of a clone of green peach aphid (Myzus persicae(Sulzer); Hemiptera: Aphididae), raised on savoy cabbage (Brassica oleraceaLinnaeus; Brassicaceae), under all possible combinations of: I) the parasitoidAphidius colemaniViereck (Hymenoptera: Braconidae); II) the predatorChrysoperla carnea(Stephens) (Neuroptera: Chrysopidae); III) the predatorAdalia bipunctata(Linnaeus) (Coleoptera: Coccinellidae); and IV) the spiderParasteatoda tepidariorum(Koch) (Araneae: Theridiidae). We demonstrate a considerably differential green peach aphid abundance, polyphenism, and fine-scale spatial distribution in response to the combination, number, and identity of the present enemy species and their interactions. Surprisingly, certain combinations led to thriving green peach aphid populations due to interference between enemies; whereas, other combinations resulted in tangible collective suppression of the population. At the frontier of agroecology and entomology, we provide fresh insights on the effects of conflict and synergy between natural enemies sharing a pest of a cash crop as prey, highlighting the consequences of the presence of a novel synanthropic spider, as a top predator, on pest regulation.

Plankton communities constitute an important part of the biodiversity in shallow lentic ecosystems (SLEs). Understanding their diversity responses to increasing human pressure is required for the effective management of SLEs. Here we assessed the relationship between different properties of phytoplankton and zooplankton communities (abundance, taxonomic and functional diversity, and taxonomic and functional composition) and human impact (HII index), limnological features of SLEs (i.e., surface area and depth, trophic state, and hydrological connectivity), the biomass of submerged macrophytes, and the abundance of planktivorous fishes. For this, we sampled zooplankton from 28 sampling sites across nine SLEs (seven ponds, one channel, and one shallow lake). For 18 sampling sites across six of the ponds, we also sampled phytoplankton. We found that phytoplankton abundance was negatively associated with the higher HII, while zooplankton abundance and species richness increased with increasing HII. Hydrological connectivity was an important predictor of both phytoplankton and zooplankton diversity and composition. The functional diversity and composition of phytoplankton were more sensitive to environmental changes than their taxonomic diversity. Opposite patterns were recorded for zooplankton diversity metrics, presumably due to the dominance of non-predatory rotifers, which maintained constant functional diversity despite variations in taxonomic diversity along environmental gradients. Our results suggest that the taxonomic and functional diversity metrics of both phytoplankton and zooplankton should be considered simultaneously since they can show contrasting responses to human pressure and environmental changes in SLEs. © 2022, The Author(s), under exclusive licence to Springer Nature Switzerland AG.

The current global rates of human impact intensification in freshwater ecosystems and their surroundings have caused an alarming loss of freshwater biodiversity and functioning across multiple trophic levels. Particularly vulnerable to anthropogenic pressures are small water bodies (SWB). However, the majority of the evidence is limited to a single community, especially macroinvertebrates, thus leaving us uncertain about cross-community multitrophic responses of freshwater consumers to anthropogenic pressure. Furthermore, the effects of human impact on trophic composition and diversity of consumers may depend on the nature of human activities. We therefore tested the effects of different co-occurring human activities (agricultural land use, gravel exploitation, road proximity, and waste input) and of the overall human-impact intensification on trophic trait diversity and composition of different animal communities in SWB. For this, four types of consumer communities (i.e., zooplankton, benthic macroinvertebrates, epiphytic macroinvertebrates, and fish community) were sampled in a total of 58 study sites in two geographic areas in Serbia and Croatia for two years. In addition to human impact, we also tested the effects of altered water properties, macrophyte biomass, and predation. Our results clearly show that human impact induced changes in the trophic diversity and the trophic composition of different consumer communities. The direction and strength of such functional shifts depended on the nature of human impact and on the type of consumer community. Furthermore, we found that the effects of human impacts on the distribution of trophic traits across all consumer communities significantly differed between trophic groups (i.e., herbivores, decomposers, and carnivores) and trophic levels (i.e., trophic position in the food web). Our findings point toward the urgent need to consider multiple stressors and a range of animal community types in future research and management of freshwater ecosystems. These results highlight the importance of a multitrophic perspective when predicting the consequences of human impact for ecosystem biodiversity and functioning.

Grasslands comprise one of Earth's dominant biomes, accounting for up to 40% of its terrestrial area (Figure 1). The fundamental components of grassland habitats are grasses and grass-like plants, but diverse assemblages of other plant life forms and diverse animal communities also contribute to grassland biodiversity. Grasses have evolved traits allowing them to cope with climatic extremes, specific soil conditions, fires, and herbivory, all of which sustain grasslands by limiting the establishment, survival, growth, and dominance of woody vegetation. Grasslands occur in almost all climatic zones, except the poles, extreme arid zones, and the highest mountains (Figure 1). Temperate grassland habitats include Eurasian steppes, North American prairies, the pampas lowlands of South America, and Patagonian steppe. Tropical and subtropical grasslands (savannas) occur mostly in Africa and Australia, but are also found in the north of South America, in the southern United States, South Asia, and Southeast Asia.

While several studies have tested the effects of anthropogenic factors on specific taxa in ponds, the simultaneous effects of the overall anthropogenic pressure along the environmental gradient on the diversity of different groups of pond communities remain unknown. In this study, we evaluated the simultaneous effects of the overall intensity of human impact and characteristics of natural pond variability on the diversity and density of macrophytes, benthic and epiphytic macroinvertebrates, and fish community and water chemistry in pond ecosystems. We found a reduction in the diversity and density of macrophytes and in the diversity of epiphytic macroinvertebrates with an increased human pressure. The effects of the intensity of human impact on the diversity of epiphytic macroinvertebrates were mediated via changes in macrophyte diversity. Benthic macroinvertebrates were not affected by an increase in the intensity of human pressure. Fish community responded to the increased human pressure with shifts in abundance through the predominance of invasive species. Natural pond variability properties affected the pond communities and water chemistry in the majority of cases. Our results conclude that for understanding the effects of human activity on pond biodiversity, integrating the simultaneous effects of multiple anthropogenic and abiotic factors in ponds is desirable.

There is a consensus that human activities affect biodiversity in pond ecosystems. However, the majority of studies have mainly focused on the direct effect of human activities on a single group, despite the fact that anthropogenically induced biodiversity loss in ecosystems occurs across multiple trophic levels and may depend on both altered habitat (e.g., water chemistry) and on trophic interactions cascading up the trophic network. In this study, we analyzed the simultaneous direct, water-chemistry mediated and trophic network cascading effects of the overall human-impact intensification on density (biomass/abundance) and richness (number of taxa) across all trophic levels in pond ecosystems. For this, we collected and combined multi-taxon data (341 taxa) for macrophytes, phytoplankton, zooplankton, benthic and epiphytic macroinvertebrates, and fishes. We showed that human-impact intensification affected the densities and richness of almost all trophic levels across the study ecosystems, and resulted in an overall negative effect on the multitrophic diversity of the entire community. We detected direct effect of human-impact intensification, but no indirect effects, on the richness of primary producers. In contrast, the indirect effects mediated through the nutrient content in the water were the most influential drivers of multitrophic diversity in the invertebrate communities. At the same time, the indirect effects through the trophic network cascades were detected mainly within the fish community. Our findings improve the mechanistic understanding of multitrophic diversity responses in ponds under the ongoing intensification of anthropogenic pressure.

Grassland biodiversity is vulnerable to land use change. How to best manage semi-natural grasslands for maintaining biodiversity is still unclear in many cases because land-use processes may depend on environmental conditions and the indirect effects of land-use on biodiversity mediated by altered abiotic and biotic factors are rarely considered. Here we evaluate the relative importance of the direct and indirect effects of grazing intensity on plant communities along an elevational gradient on a large topographic scale in the Eastern Carpathians in Ukraine. We sampled for two years 31 semi-natural grasslands exposed to cattle grazing. Within each grassland site we measured plant community properties such as the number of species, functional groups, and the proportion of species undesirable for grazing. In addition, we recorded cattle density (as a proxy for grazing intensity), soil properties (bare soil exposure, soil organic carbon, and soil pH) and densities of soil decomposers (earthworms and soil microorganisms). We used structural equation modelling to explore the direct and indirect effects of grazing intensity on plant communities along the elevation gradient. We found that cattle density decreased plant species and functional diversity but increased the proportion of undesirable species. Some of these effects were directly linked to grazing intensity (i.e., species richness), while others (i.e., functional diversity and proportion of undesirable species) were mediated via bare soil exposure. Although grazing intensity decreased with elevation, the effects of grazing on the plant community did not change along the elevation gradient. Generally, elevation had a strong positive direct effect on plant species richness as well as a negative indirect effect, mediated via altered soil acidity and decreased decomposer density. Our results indicate that plant diversity and composition are controlled by the complex interplay among grazing intensity and changing environmental conditions along an elevation gradient. Furthermore, we found lower soil pH, organic carbon and decomposer density with elevation, indicating that the effects of grazing on soil and related ecosystem functions and services in semi-natural grasslands may be more pronounced with elevation. This demonstrates that we need to account for environmental gradients when attempting to generalize effects of land-use intensity on biodiversity.

Phloem-feeding insects strive to offset the disadvantageous effects of stressors to sustain their offspring and survive. Adaptive responses to environmental stress are not well understood under complex influences of companion planting, natural enemies, and host gradient. In this study, under predation by lacewing Chrysoperla carnea Stephens (Neuroptera: Chrysopidae), we survey the responses of green peach aphid Myzus persicae Sulzer (Hemiptera: Aphididae), reared on different densities of cabbage Brassica oleracea L. (Brassicales: Brassicaceae) to its shallot companion Allium cepa (L.) var. aggregatum G. Don (Asparagales: Amaryllidaceae). Firstly, aphid aggregative abundance was strongly influenced by shallot perturbation, predator presence and changes in cabbage-host biomass, altering aphid phenotypic plasticity. Interestingly, the shallot and predation negative impacts can be of similar magnitudes. Secondly, changes in the cabbage-host availability and biomass, especially under predation, had a strong impact on aphid traits. Our study underscores the benefits of including shallots as crop-companions in augmenting pest control, but also suggests that the outcome of coupling companion planting with natural enemies is context-dependent and thus should be empirically applied. At the confluence of ecology and agronomy, this work provides insights on how manipulated functional biodiversity may function as an alternative strategy for pestilent herbivory management in model and green-house systems.

Non-consumptive effect of predation is a well-researched subject of which certain temporal, non-consumptive and predator-mimetic facets are yet to be investigated in plant-parasite systems. Here we focus on the consequences of the exposure of a pest population to predator-associated risk. One clone of the green peach aphid Myzus persicae (Sulzer), raised on a model crop Brassica oleracea (L.), was exposed to different regimes of risks associated with the aphidophagous predator ladybird Coccinella septempunctata (L.). This encompassed consumption, consumption alternated by non-competitive predation risk, presence of isolated predators with and without aphid feed, dead predator, predator dummy, scented (mimed) dummy, treated plants (or soil) with predator-borne cues, and predator removal. Over time, the respective risk regimes led to variable yet conspicuous suppression of the prey population. For example, unlike predator removal, ladybird corpses and dummies had considerable persistent negative effects on aphid reproductive success. Also, by the end of the experiment, polyphenism (winged morph production) varied across the risk regimes and was animated under the presence of a starved isolated predator, but faded when a predator corpse was present, and vanished in the presence of a predator dummy. Using a model aphid-crop system, we provide timely and novel insights on differential impacts of a variety of predator-associated cues on the population growth and phenotypic plasticity of the parthenogenetic pest in question. This work has implications for the rapidly developing area of the ecology of fear and thus merits applications across different eco-agricultural contexts.

This article compares 13 network properties of food webs of 31 Ukrainian grasslands. The properties are: network size N, trophic link number L, trophic classes Cl, system connectance C, link density LD, total system throughflow TST, network cycling FCI, ascendency AS, developmental capacity DC, indirect effects dominance IE, system aggradation AI, system synergism SI, and mutualism MI. Our results show these properties are highly correlated and can be aggregated into the three latent factors. The first factor includes N, TST, AS, DC, SI, L, and LD, where network size N appears to be a central defining variable. The second latent factor includes FCI, AI, and Cl, and is driven by indirect effects dominance IE. The third factor includes mutualism MI and connectance C, the last being the driving variable. Network Synergism SI is negatively correlated with the other network properties, while all others are positively intercorrelated. Network connectance appears to be a scale invariant property, while link density is highly sensitive to network size. Our data also show that network mutualism MI is more tied to the network complexity than simply to system scale or number of feeding links.

Black locust colonization of floodplains can exacerbate the problems associated with increasing nitrogen inputs into the riparian area and river ecosystem. In this study we compare the nitrogen budgets of two sites of floodplain ecosystem, one is colonized by invasive black locust and the other is forested by the indigenous willow species. Our data report the considerably higher N-flow rates, nitrogen storage and the faster total N-related ecosystem processes in the Robinia site in comparison to the indigenous Salix site of the study floodplain. Black locust affects the nitrogen cycle in the study riparian ecosystem through the N-fixation, high N-content litterfall and rapid litter decomposition that results in the increase of the nitrogen flow into the river and contaminates the water. Black locust appeared to reduce the conservation values of colonized areas and adjacent river. Restoration strategies that remove the black locust from invaded sites and prevent the further invasion will slow down the contamination. However, high availability of nitrogen in soil and soil degradation might have a long-term effect on floodplain ecosystem after the restoration.

An important question in ecology is whether the food-web structure and ecosystem functions are related. This paper provide an empirical evidence for the food-web complexity–ecosystem properties relationships using the comparative analysis of food webs in seven mountain pastoral grasslands located in the Carpathian Mountain area of the Chernivtsi Region, Ukraine. Biomass of plant functional groups; grazing intensity; richness of different functional groups of the soil microorganisms; and geographical location of the study grasslands are observed ecosystem properties. Trophic networks consisting of N food and feeding categories (nodes, compartments) joined by L food transfers (links) were constructed for each studied pasture and the following network measures of their graph characteristics (“topology”) determined: food-web size ( N ), number of links ( L ), link density ( LD = L / N ), and connectance ( C = L / N 2 ). Also the number of trophic classes and size of each trophic class are incorporated as the properties of the food-web architecture. Our data reveal that increase in species richness and food-web complexity increases the biomass of forbs within the study grasslands. Grazing intensity shows negative but statistically insignificant correlation with network measures. Our findings also reveal the longitudinal changes in connectance variation across the study food webs. It shows that temperature and elevation changes may also contribute toward the food-web connectance variation within the study area. Overall, our findings report plants to be the defining in network architecture. Furthermore grazing-susceptible plants show to be the driving variable in a food-web structure of the study grasslands. Our findings also reveal new aspects in behavioral patterns of food-web properties in relation to each other. Our data report link density to be the most sensitive parameter in relation to the other food-web measures. In contrast, connectance shows the least sensitivity to all other network measures, but the most sensitivity to the observed ecosystem parameters.

This paper analyses the transient dynamics, steady states, and a set of diagnostic system-wide properties of a linear flow-quantified pastoral food web from the Chernivtsi Region of Ukraine. The web in question is one of 31 so-described; it contains 86 nodes and 496 links. On-line simulation and network analysis software EcoNet was used to quantify transient dynamics, steady states, and eleven system-wide index parameters. Food-web flows were classified into inputs, interior flows, and outputs. The last two (endogenous) were represented by linear, mass-balance, flow coefficients. The three sets, inputs plus these coefficients, were systematically manipulated in their entirety in different combinations over seven orders of magnitude to determine their effects on system properties. The results of these trials are described and interpreted. They show that linear descriptions of empirical food webs harbor considerable dynamic and relational complexity.

Ecological network analysis provides various indices that serve as whole-system properties. Several attempts were made to assess system-level organizational measures and investigate the relationships between them. But the limitations in data availability associated with the difference in type of network models, their aggregation, currency, and timescale make direct comparisons of network properties complicated. To overcome this problem we compared seven empirical trophic networks of geographically close pastoral ecosystems. For comparative network analysis to be valid, the study food webs were similarly constructed with no difference in aggregation, currency, or timescale. We investigated the sensitivity and robustness in the relations between the following network analysis system-wide properties: degree of system connectance, link density, total system throughflow, cycling degree, ascendency, developmental capacity, indirect effects dominance, system aggradation, system synergism, and mutualism.