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Trophic coherence and non-normality are both ways of describing the overall directionality of directed graphs or networks. Trophic coherence can be regarded as a measure of how neatly a graph can be divided into distinct layers, whereas non-normality is a measure of how unlike a matrix is with its transpose. We explore the relationship between trophic coherence and non-normality by first considering the connections that exist in literature and calculating the trophic coherence and non-normality for some toy networks. We then explore how persistence of an epidemic in an SIS model depends on coherence and how this relates to the non-normality. A similar effect on dynamics governed by a linear operator suggests that it may be useful to extend the concept of trophic coherence to matrices, which do not necessarily represent graphs. [ABSTRACT FROM AUTHOR]

There are two contrasting hypotheses regarding the drivers of biomass‐distribution among trophic levels within ecosystems. Energetic or bottom–up models propose control by supply of energy, either from autotrophy or from the underlying trophic level. Dynamical or top‐down models propose control by predators in the overlying trophic level. Although multiple approaches have been used to reconcile these hypotheses, they have rarely considered the evolutionary pressures created by different distributions of biomass. Here, we study the effects of these evolutionary processes using an agent‐based, spatially‐explicit, eco‐evolutionary model. We demonstrate that, when ecosystems are simple and predator–prey relationships between species are fixed and do not evolve, primary productivity limits the number of trophic levels. In this case, the abundance in the top trophic level is always limited by productivity. However, productivity‐limited trophic levels subject those below them to limitation by predation, and predation‐limited trophic levels allow trophic levels below them to grow until limited by productivity. These results match the expectations of the exploitation ecosystems hypothesis (EEH), which predicts the same pattern of alternating top–down and bottom–up control on trophic levels. When species are able to evolve to adaptively adjust their trophic levels, however, selection is liable to lead to collapse of the trophic pyramid through prey switching. Under these conditions, all trophic levels experience bottom–up control. When the evolution of prey switching is restricted, higher trophic levels are evolutionarily stable and the predictions of the EEH are once again met; the stability of long food chains is thus dependent on the difficulty associated with prey switching. These results suggest that, at least under the combinations of model parameters explored in this study, evolutionary limitation is key to maintaining trophic structure. [ABSTRACT FROM AUTHOR]

Globally, marine fish communities are being altered by climate change and human disturbances. We examined data on global marine fish communities to assess changes in community‐weighted mean temperature affinity (i.e., mean temperatures within geographic ranges), maximum length, and trophic levels, which, respectively, represent the physiological, morphological, and trophic characteristics of marine fish communities. Then, we explored the influence of climate change and fishing on these characteristics because of their long‐term role in shaping fish communities, especially their interactive effects. We employed spatial linear mixed models to investigate their impacts on community‐weighted mean trait values and on abundance of different fish lengths and trophic groups. Globally, we observed an initial increasing trend in the temperature affinity of marine fish communities, whereas the weighted mean length and trophic levels of fish communities showed a declining trend. However, these shift trends were not significant, likely due to the large variation in midlatitude communities. Fishing pressure increased fish communities' temperature affinity in regions experiencing climate warming. Furthermore, climate warming was associated with an increase in weighted mean length and trophic levels of fish communities. Low climate baseline temperature appeared to mitigate the effect of climate warming on temperature affinity and trophic levels. The effect of climate warming on the relative abundance of different trophic classes and size classes both exhibited a nonlinear pattern. The small and relatively large fish species may benefit from climate warming, whereas the medium and largest size groups may be disadvantaged. Our results highlight the urgency of establishing stepping‐stone marine protected areas to facilitate the migration of fishes to habitats in a warming ocean. Moreover, reducing human disturbance is crucial to mitigate rapid tropicalization, particularly in vulnerable temperate regions. [ABSTRACT FROM AUTHOR]

The role of keystone species in maintaining ecosystem stability is a crucial aspect of ecology. Identifying key mammalian species within an ecosystem requires a systematic approach, utilizing criteria and indicators derived from species characteristic variables. This study presents a framework to identify key mammalian species based on various ecological, structural, and functional factors. By developing a mechanistic model of energy flow in food webs and trophic levels, the model aims to pinpoint each species' role in the stability and sustainability of biomass flow within the ecosystem. Known as KVT version 1.0, the model explains the role of each characteristic variable of mammalian species, predicts population growth, elucidates species interactions at trophic levels, and assesses species-specific dietary compositions, including food requirements, reproduction, and activity. Factor analysis of model outputs has produced equations to determine the value of keystone species (Kv), indicating the role of mammalian species in the stability and sustainability of biomass flow in the ecosystem. Keystone species, as identified by this model, are primarily small mammals of the families Muridae, Sciuridae, Tupaiidae, Ptilocercidae, Hystricidae, Viverridae, and Herpestidae, demonstrating omnivorous and herbivorous trophic levels. This model can serve as a valuable framework for conservation management of biodiversity in an ecosystem, with potential for expansion to include characteristics of non-mammalian species in future research. [ABSTRACT FROM AUTHOR]

Foundation species, such as seagrasses, trees, and corals, form the biotic basis for many ecosystems. They engineer local habitats and can support many faunal species through trophic (e.g. providing feeding grounds) or non‐trophic (e.g. providing predation shelters and spawning grounds) mechanisms. How the supporting effects of foundation species on fauna change across multiple trophic levels remains poorly understood. We investigated how a foundational seagrass supported faunal species at different trophic levels, using a series of comparative surveys, diet analyses, and field experiments. We found that seagrasses substantially enhanced marine fauna across all but one of four trophic levels. Primary, secondary, and top consumers were significantly more abundant, whilst tertiary consumers were similarly or less abundant in seagrass beds than on unvegetated mudflats. Importantly, seagrasses supported fauna of different trophic levels via different trophic or non‐trophic mechanisms; seagrasses provided mainly feeding, refuging and feeding, feeding, and spawning grounds for primary, secondary, tertiary, and top consumers, respectively. Our work reveals that seagrasses support fauna from primary to top trophic levels via different trophic and non‐trophic mechanisms. Our findings highlight that protecting and restoring seagrasses is critical to enhancing fauna across multiple trophic levels and can inform conservation strategies targeted for fauna at different trophic levels. Our study can help stimulate future studies from other ecosystems to test how foundation species affect fauna across different trophic levels. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

The role of keystone species in maintaining ecosystem stability is a crucial aspect of ecology. Identifying key mammalian species within an ecosystem requires a systematic approach, utilizing criteria and indicators derived from species characteristic variables. This study presents a framework to identify key mammalian species based on various ecological, structural, and functional factors. By developing a mechanistic model of energy flow in food webs and trophic levels, the model aims to pinpoint each species’ role in the stability and sustainability of biomass flow within the ecosystem. Known as KVT version 1.0, the model explains the role of each characteristic variable of mammalian species, predicts population growth, elucidates species interactions at trophic levels, and assesses species-specific dietary compositions, including food requirements, reproduction, and activity. Factor analysis of model outputs has produced equations to determine the value of keystone species (Kv), indicating the role of mammalian species in the stability and sustainability of biomass flow in the ecosystem. Keystone species, as identified by this model, are primarily small mammals of the families Muridae, Sciuridae, Tupaiidae, Ptilocercidae, Hystricidae, Viverridae, and Herpestidae, demonstrating omnivorous and herbivorous trophic levels. This model can serve as a valuable framework for conservation management of biodiversity in an ecosystem, with potential for expansion to include characteristics of non-mammalian species in future research.

In plant‐associated communities, foraging insects aim to find different resources of interest. Herbivores look for the most nutritious plant tissues, pollinators for sweet nectar and protein‐rich pollen, and carnivores for their preferred prey. Although these foragers look for different resources, they face similar problems: resource cues are often highly variable and need to be detected in complex environments among non‐resources. Search templates—a subset of stimuli that is likely correlated with the occurrence of a particular resource—help foragers across trophic levels to find their resources. However, search‐template‐based foraging can also cause perception errors.Here, we synthesize knowledge on foraging by insects from functional groups belonging to different trophic levels to reveal common problems experienced by foragers and strategies to solve such problems. We focus mostly on volatile‐based foraging because this searching strategy is best studied across functional groups.We argue that search templates are both multimodal (including multiple trait types, e.g. odour and visual) and hierarchical (including multiple foraging steps). Search templates are plastic and updated by experience to match the dynamic foraging environment over time.By comparing insects from different functional groups spanning multiple trophic levels, we have identified important missing gaps on cue use and foraging strategies which should be addressed in the future in order to reduce knowledge asymmetries among functional groups about search‐template‐based foraging. We propose a way to achieve this goal arguing that studies on less well investigated functional groups can advance rapidly by borrowing, testing and adjusting already available hypotheses and theories formulated for other insect groups. Knowledge of search‐template‐based foraging across functional groups will give new insights into the evolution of foraging behaviour in complex ecological communities, help predict ecological consequences of large‐scale human‐made disturbances and help optimize insect‐delivered ecosystem services (pollination and biological control) in cropping systems. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Trophic coherence and non-normality are both ways of describing the overall directionality of directed graphs or networks. Trophic coherence can be regarded as a measure of how neatly a graph can be divided into distinct layers, whereas non-normality is a measure of how unlike a matrix is with its transpose. We explore the relationship between trophic coherence and non-normality by first considering the connections that exist in literature and calculating the trophic coherence and non-normality for some toy networks. We then explore how persistence of an epidemic in an SIS model depends on coherence and how this relates to the non-normality. A similar effect on dynamics governed by a linear operator suggests that it may be useful to extend the concept of trophic coherence to matrices, which do not necessarily represent graphs.

The dataset contains insights into the molluscan diversity associated with seagrass and seasonal dynamics in a subtropical arid zone in the southern Gulf of California. The dataset includes the number of species, taxonomy, seasonal abundance data, trophic composition, biomass of molluscan, and biomass of seagrass (H. wrightii). This dataset is referenced in the study titled: “Diversity and seasonal variation of the molluscan community associated with the seagrass Halodule wrightii in a marine protected area in the southern Gulf of California” (Pérez-Estrada et al., 2023) [1].

Predation causes suffering and the premature deaths of prey animals. With innovative technologies on the horizon, humanity could phase it out. We argue that herbivorisation, i.e., turning carnivorous species into herbivorous ones with biotechnologies, is better than other strategies for ending predation, because it is the one most likely to preserve environmental values such as biodiversity and receive democratic support. Pressure on vegetation in herbivorised ecosystems would increase, but fertility control could relieve this pressure. We respond to other objections and conclude that the process should be considered as a future megaproject to reduce naturogenic harms. [ABSTRACT FROM AUTHOR]

Ongoing habitat loss and fragmentation caused by human activities represent one of the greatest causes of biodiversity loss. However, the effects of habitat loss and fragmentation are not felt equally among species. Here, we examined how habitat loss influenced the diversity and abundance of species from different trophic levels, with different traits, by taking advantage of an inadvertent experiment that created habitat islands from a once continuous forest via the creation of the Thousand Island Lake, a large reservoir in China. On 28 of these islands with more than a 9000‐fold difference in their area (0.12–1154 ha), we sampled plants, herbivorous insects, and predatory insects using effort‐controlled sampling and analyses. This allowed us to discern whether any observed differences in species diversity were due to passive sampling alone or to demographic effects that disproportionately influenced some species relative to others. We found that while most metrics of sampling effort‐controlled diversity increased with island area, the strength of the effect was exacerbated for species in higher trophic levels. When we more explicitly examined differences in species composition among islands, we found that the pairwise difference in species composition among islands was dominated by species turnover but that nestedness increased with differences in island area, indicating that some species are more likely to be absent from smaller islands. Furthermore, by examining trends of several dispersal‐related traits of species, we found that species with lower dispersal propensity tended to be those that were lost from smaller islands, which was observed for herbivorous and predatory insects. Our results emphasize the importance of incorporating within‐patch demographic effects, as well as the taxa and traits of species when understanding the influence of habitat loss on biodiversity. [ABSTRACT FROM AUTHOR]

In the present world, everyone is health, hygiene, and beauty conscious. Most households use different personal care products (PCPs) to keep themselves clean and hygienic. But when it comes to disposal, not much care is taken. PCPs are being liberated into the environment on a regular basis causing harm to the ecosystem. The prevalence of these PCPs as soaps, nail paints, hair dyes, fragrances, emulsifiers, antioxidants, ultraviolet absorbers, preservatives, disinfectants, etc. is posing severe health concerns. It has been studied that together these PCPs being biologically active and highly persistent, in turn impacts the lives of living beings. This review work aimed to elucidate and analyze the problems associated with personal care products when discharged into the aquatic system from different sources that cause detrimental effects on the organisms at different trophic levels and on human beings which has been included in this discussion, the variety of sources and how they impact the aquatic life as well as the movement of the emerging toxicants to the higher trophic levels through the food chain. This work also has analyzed the bioremediation of a few toxicants like, paraben, phthalate, sulphate by some potential microorganisms and the limitations in the microbial remediation process. [ABSTRACT FROM AUTHOR]

Artificial light at night (ALAN) is a global change driver but how it interacts with plant invasions is unclear. Determining this requires understanding direct effects of ALAN on physiology, phenology, growth, and fitness of both invasive and native plant species and its indirect effects mediated through mutualistic and/or antagonistic interactions. [ABSTRACT FROM AUTHOR]

This study presents a comprehensive assessment of persistent organic pollutants (POPs) in the blubber of a stranded blue whale found on the coast of Taiwan. The analysis included polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane (DDT), Hexachlorobenzene (HCB), and polybrominated diphenyl ethers (PBDEs). The whale exhibited evident signs of emaciation, including low body weight, reduced blubber fat content, and thin blubber thickness. The dominant fatty acid type detected in the blubber was short-chain monounsaturated fatty acids (SC-MUFA), known to aid in thermoregulation. Stable isotope ratios indicated that the blue whale occupied a lower trophic position compared to a fin whale, suggesting its proximity to krill habitats in the Southern Ocean for feeding. The average concentrations of DDTs (1089.2 ± 4.7 ng/g lw; ΣDDT) and PCBs (1057.1 ± 49.8 ng/g lw) in the blubber were almost one order of magnitude higher than PAHs (41.7 ± 10.0 ng/g lw), HCB (70.6 ± 2. ng/g lw), and PBDEs (7.2 ± 1.2 ng/g lw). Pollutant concentrations in this individual blue whale were comparable to levels found in Norway, higher than those found in Chile, and notably lower than those found in Canada and Mexico. Calculating the biomagnification factor (BMF) for the POPs from krill (Euphausia superba) to the blue whale revealed significant bioaccumulation of pollutants in this particular whale. Additional research is imperative to achieve a thorough comprehension of bioaccumulation of POPs and their potential toxicological impacts on whale health. [ABSTRACT FROM AUTHOR]

The results of analysis on the feeding patterns and assessment of the trophic levels and niches in two Zoarcidae species Bothrocara brunneum and B. zestum from the deep-water areas in the Sea of Okhotsk and the Pacific Ocean off the Lesser Kuril Ridge have been reported. Both species feed on various benthic and mesobenthic forage organisms including crustaceans, mesopelagic fishes, cephalopods, bivalved mollusks, polychaetes, and echinoderms. Despite the dominant food component variability across different water areas, crustaceans represent the major food group. In addition, both fish species have similar food sources and, therefore, trophic niches. It is proven by estimation with the standard ellipse area method via the Bayesian probability, showing rather similar widths of trophic niches: 17.7 for B. zestum and 16.6 for B. brunneum. The actual values for stable nitrogen isotope ratios (δ15N) in food components indicate a wide range of trophic levels in the analyzed species: from 2.08 to 4.36 in B. zestum and from 1.97 to 4.42 in B. brunneum, which can prove their plasticity in selecting the food items. The ranges of values for the stable carbon isotope ratios (δ13C) in food components indicating the basal food sources reached 15.04 to 23.43‰ for B. zestum and 15.07 to 23.43‰ for B. brunneum. The survey-based new information on two species feeding was obtained to determine their roles in the trophic structures of ecosystems in the studied water areas. [ABSTRACT FROM AUTHOR]

Simple Summary: In this study, the author conducted a comparative analysis of Greater lizardfish (Saurida tumbil) in the Beibu Gulf during two distinct periods (2010 and 2020), aiming to comprehend the variations in dietary strategies and trophic levels while investigating the driving factors influencing S. tumbil in the study area. Over the past decade, the main prey items of this species have been fishes, followed by cephalopods and crustaceans. However, changes in the community structure and primary prey resources have led the S. tumbil population to diversify their prey species, utilize alternative resources, and expand their foraging space. The timing and magnitude of ODSs varied between the two periods. In comparison to 2010, the proportion of population feeding on pelagic–neritic prey significantly increased, and the δ15N values decreased, indicating that the shift in the ecological types of preferred prey from demersal to pelagic–neritic was the primary cause of the decrease in trophic levels. Understanding dietary behavior during the individual development of marine predators and its temporal variations elucidates how species adapt to changes in marine resources. This is crucial for predicting marine predators' habitat selection and the natural population's responses to environmental changes. The authors conducted a comparative analysis of dietary shift strategies and trophic level variations in Greater lizardfish (Saurida tumbil) in the Beibu Gulf during two distinct periods (2010 and 2020) using stomach content and stable isotope analysis methods. Possible driving factors for these changes were also explored. Changes in the fishery community structure and the decline in the abundance of primary prey resources have led the S. tumbil population to diversify their prey species, utilize alternative resources, and expand their foraging space. However, the species' foraging strategy, characterized by chasing and preying on schooling and pelagic prey, promoted stability in their feeding behavior across spatial and temporal scales. The main prey items remained demersal and pelagic fish species, followed by cephalopods and crustaceans. Similar to other generalist fish species, ontogenetic dietary shifts (ODSs) indicated a partial transition towards larger prey items. However, the timing and magnitude of the ODSs varied between the two periods, reflecting life-history variations and adaptive adjustments to environmental changes. In comparison to 2010, the population's mean body length (BL) increased in 2020, and the proportion of the population feeding on pelagic–neritic prey significantly increased. However, the δ15N values were lower, indicating that the shift in the ecological niche of preferred prey from demersal to pelagic–neritic was the primary cause of the decrease in trophic levels. In the future, we will conduct further quantitative research integrating the spatiotemporal data of both predators and prey to clarify the relationships between marine predators' feeding behavior, trophic levels, and changes in prey community structure. [ABSTRACT FROM AUTHOR]

Biodiversity loss is one of the major crises facing humanity today, and with none of the biodiversity targets represented by the Aichi Biodiversity Targets being met, there is an urgent need to promote transformative change to halt and reverse the trend of biodiversity loss. Nature-based solutions (NbS) have emerged as an important way to address the global crisis due to its inherent principles involving holistic and systemicness, diversity, stability, sustainability, trade-offs, and compatibility. The relationship between biodiversity and NbS is analyzed from a mechanistic and functional perspective, and the pathway of NbS as a proxy for biodiversity conservation is revealed by restoring of ecosystem complexity and trophic levels to put nature on the path. We here propose the dual intensions of promoting NbS for biodiversity conservation, as (1) the goal aimed at enhancing diversity, stability, and sustainability of ecosystem, and (2) the tool involves use natural processes. Based on the above understanding of the link between NbS and biodiversity, this paper further compares the conceptual connotation of NbS with the consistency of biodiversity conservation, as well as the NbS methods for biodiversity conservation including natural, agricultural and urban area. Practical cases of NbS for biodiversity conservation or synergy of NbS for biodiversity are summarized in align with differentiated typical ecosystems. The multiple benefits of NbS for biodiversity conservation, climate change and sustainable development are discussed. The vision of integrating NbS into strategic planning for biodiversity conservation is presented to provide a reference for promoting the implementation of Kunming-Montreal Global Biodiversity Framework and the mainstreaming of NbS in biodiversity conservation.

Biological interactions and associations underlie life's processes at every level of organization. Here, we present a classroom activity that allows students to visualize and understand the connections within almost any biological system, from cell functions to ecological relationships. We recommend that instructors implement this activity to review course content and enhance students' system-thinking abilities. [ABSTRACT FROM AUTHOR]

Understanding fire effects on multitrophic levels is critical to the context of changes in fire regime and climate. Insects located at higher trophic levels, like parasitoids, are more vulnerable to habitat changes than insect herbivores because they need well‐established populations of their hosts to survive. Currently, fire effects on parasitoids and their interactions with their hosts are unknown.Our aim was to study the changes in abundance, richness and species composition, as well as the food web structure in a system involving parasitoids and galling insects under different fire scenarios. We asked whether potential changes in abundance, species richness and composition of parasitoid communities are explained by galled plant abundance, species richness and composition of galling insects, and how fire affects the structure of galling insect–parasitoid food webs.The highest parasitoid richness was found in the 9 years after fire scenario, whereas parasitoid abundance was not affected by fire. The parasitoid species composition in the 9 years after fire scenario was different from that in the unburned and 3 years after fire scenarios. Parasitoid communities were modulated by galled plant abundance, species richness and composition of galling insect communities. Vulnerability was significantly higher in 9 years after fire scenarios, but it increased with increasing network size.Fire affects the community of parasitoids through changes in their host communities. Differences in exclusivity to fire scenarios and diet specialisation of parasitoid species and galling insect richness may explain the patterns found. Our study supports evidence that fire creates habitats heterogeneous in the availability of hosts shaping the parasitoid communities, with a bottom‐up effect in food webs. Additionally, in burned areas were recorded unique galling insect–parasitoid interactions. [ABSTRACT FROM AUTHOR]

Understanding environmental drivers of species diversity has become increasingly important under climate change. Different trophic groups (predators, omnivores and herbivores) interact with their environments in fundamentally different ways and may therefore be influenced by different environmental drivers. Using random forest models, we identified drivers of terrestrial mammals' total and proportional species richness within trophic groups at a global scale. Precipitation seasonality was the most important predictor of richness for all trophic groups. Richness peaked at intermediate precipitation seasonality, indicating that moderate levels of environmental heterogeneity promote mammal richness. Gross primary production (GPP) was the most important correlate of the relative contribution of each trophic group to total species richness. The strong relationship with GPP demonstrates that basal‐level resource availability influences how diversity is structured among trophic groups. Our findings suggest that environmental characteristics that influence resource temporal variability and abundance are important predictors of terrestrial mammal richness at a global scale. [ABSTRACT FROM AUTHOR]

Horizontal transmission of bacteria to varied hosts can maintain and even expand microbial niches. We previously found that the aphid gut bacterium Serratia symbiotica strain SsMj can be transmitted to ladybird beetles via predation, but whether the predator is a new host, a reservoir or a dead end of this bacterium is unknown. This study aims to provide a clear picture of SsMj circulation from aphids to plants and predators. We first found that SsMj in aphids and ladybirds was abundantly distributed not only in digestive tracts but also in droppings. We found no evidence for vertical transmission of SsMj to aphid offspring. Instead, we showed that it could be transmitted to conspecific aphids by sharing the same plant or contacting honeydews. The key finding of this study is that SsMj was transmitted from aphids to ladybirds through predation, while ladybirds could also transfer SsMj back to aphids, possibly through feces. Together, this evidence suggests that SsMj is able to survive in the digestive tracts and droppings of insects and to expand its host range with plants and predators as reservoirs. [ABSTRACT FROM AUTHOR]

The food chain length represents how much energy reaches different trophic levels in food webs. Environmental changes derived from human activities have the potential to affect chain length.We explore how habitat area and edges affect chain length through: (1) a bottom‐up effect of abundance ('pyramid hypothesis'); (2) the truncation of the highest trophic level ('trophic‐rank hypothesis'); and (3) changes in species connectivity patterns ('connectivity hypothesis').We built plant‐leaf miner‐parasitoid food webs in 19 remnants of a fragmented Chaco forest from central Argentina. On each remnant, we constructed food webs from different locations at the forest interior and edges. For each food web, we registered the abundance of species, the species richness of each trophic level, estimated the connectivity of their networks, and the average food chain length. We used structural equation models to evaluate the direct and indirect effects of habitat area and edge/interior location on food chain length mediated by species richness, abundance and connectivity.We found no direct effects of habitat area on chain length but chains were longer at forest edges than at their interior. The three mechanisms were supported by our results, although they showed different strengths. First, we found that the interior favours a bottom‐up abundance effect from herbivores to parasitoids that positively affected chain length; second, we found that the forest area positively affects plant richness, which has a strong effect on the number of resources used by consumers, with a positive effect on chain length. Third, the remnant area and interior position favoured plant richness with a negative effect on the abundance of parasitoids, which had a positive effect on chain length. In general, the strongest effects on chain length were detected through changes in abundance rather than species richness although abundance was less affected by habitat fragmentation.We evaluated for the first time the effects of human‐driven habitat fragmentation on the length of trophic chains in highly diverse plant‐herbivore‐parasitoid networks. Despite the loss of species, small habitat fragments and edges embedded in the agricultural matrix can support interaction networks, making them conservation targets in managed landscapes. [ABSTRACT FROM AUTHOR]

Carbon‐focused climate mitigation strategies are becoming increasingly important in forests. However, with ongoing biodiversity declines we require better knowledge of how much such strategies account for biodiversity. We particularly lack information across multiple trophic levels and on established forests, where the interplay between carbon stocks, stand age, and tree diversity might influence carbon–biodiversity relationships. Using a large dataset (>4600 heterotrophic species of 23 taxonomic groups) from secondary, subtropical forests, we tested how multitrophic diversity and diversity within trophic groups relate to aboveground, belowground, and total carbon stocks at different levels of tree species richness and stand age. Our study revealed that aboveground carbon, the key component of climate‐based management, was largely unrelated to multitrophic diversity. By contrast, total carbon stocks—that is, including belowground carbon—emerged as a significant predictor of multitrophic diversity. Relationships were nonlinear and strongest for lower trophic levels, but nonsignificant for higher trophic level diversity. Tree species richness and stand age moderated these relationships, suggesting long‐term regeneration of forests may be particularly effective in reconciling carbon and biodiversity targets. Our findings highlight that biodiversity benefits of climate‐oriented management need to be evaluated carefully, and only maximizing aboveground carbon may fail to account for biodiversity conservation requirements. [ABSTRACT FROM AUTHOR]

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Amphibians are a highly vulnerable taxonomic group that hate suffered population declines worldwide. As amphibians serve critical links between trophic levels and facilitate nutrient recycling, it is critical to understand how their species richness, abundance, and phenology shift over time. Because amphibian populations naturally fluctuate, short-term monitoring can provide insight into how amphibian communities respond to proximate changes in weather conditions, which is helpful for predicting long-term responses to climate change. We used pitfall traps to examine interannual variation of the amphibian community at Powdermill Nature Reserve (PNR) in Pennsylvania during 2020-2021 to protide critical details for future long-term monitoring. Mean monthly temperature and precipitation did not van significantly between years, but monthly captures per sampling effort declined and monthly biomass per sampling effort increased from 2020 to 2021. Despite a lack of significant relationships between total amphibian captures and temperature and precipitation, peak abundance shifted earlier, and individuals were larger in 2021 compared to 2020. Interestingly, individual species biomass was predicted by an interaction between temperature and precipitation, suggesting individual species will vary in vulnerability to climate change, but the amphibian community as a whole at PNR is resilient to minor fluctuations in temperature and precipitation., INTRODUCTION Amphibians are one of the most threatened taxonomic groups, with over 30% of species threatened globally (Stuart et aL, 2004) due to a suite of biological traits making them [...]

Biodiversity is threatened by global changes, but related research has focused primarily on species or functional group diversity, neglecting their interaction networks. The latter are particularly sensitive to global changes and essential for biodiversity maintenance. Furthermore, multiple global change factors are typically examined separately, rather than in concert which is more realistic in nature.To explore the responses of arthropod networks to multiple global changes, we conducted a field experiment in temperate grassland in northeast China, in which nitrogen (N) deposition, drought, snowmelt timing and their interactions were manipulated. We constructed and assessed networks of arthropod functional groups, and explored their responses to changes in plant communities and the abiotic environments.Nitrogen addition decreased arthropod network complexity because increased foliar N and simplified plant community strengthened trophic chains along a single pathway, weakening the net effect of other pathways. However, experimental drought decreased network complexity by filtering out plant species and changing micro‐habitats. While delayed snowmelt significantly increased arthropod abundance only in early spring, its interaction with N addition or with drought had various impacts on arthropod functional groups. Our results suggest that the interaction of arthropod consumers with plant species richness and with plant nutrients finally reduced the robustness, connectedness and function of entire species/functional group networks in response to global change factors.In conclusion, species loss and increasing plant nutrient concentrations are key factors simplifying networks under multiple global changes, and such simplification is likely to be strengthened if coupled with changes in micro‐habitats. Our study highlighted that the effects of multiple global change factors should be studied in concert, even though they occur in different seasons, so that their effects on ecological networks can be perceived as a panorama. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Plankton play a key role in marine food webs by producing and transferring organic matter and energy to higher trophic levels. To define the trophic structure and interactions within the planktonic communities in the Gulf of Naples, we determined carbon and nitrogen stable isotope ratios in particulate organic matter (POM, <20 μm), phytoplankton (20–200 μm), and bulk (unsorted) and sorted mesozooplankton (200–2000 μm) on a weekly basis in 2019. The stable isotope values of POM and, to a lesser extent, phytoplankton reflected the short‐term (weekly) alternation between offshore and coastal waters within seasonal variability. Although the isotopic signatures of coastal and offshore sources were still detectable in bulk mesozooplankton, δ13C and δ15N of single groups remained almost unchanged throughout the year. The trophic niches of mesozooplankton groups defined using the Stable Isotope Bayesian Ellipses in R software showed a high degree of overlap among them, which was corroborated by the tendency of most groups toward omnivory, beyond their known feeding habits, as indicated by MixSIAR models. Collectively, our results highlight that the complex network of interactions within the planktonic community in the Gulf of Naples can buffer natural variability due to the specific hydrographic features of the system. This characteristic makes the trophic structure of this community an ideal model for monitoring the response of planktonic food webs to climate‐ and anthropic‐driven changes. [ABSTRACT FROM AUTHOR]

In this study, we analyzed the trophic structure and carbon sources supporting fish assemblages of five low-productivity rivers with different dimensions. Using carbon (δ13C) and nitrogen (δ15N) isotope ratios, we identified the major carbon sources to fish species and estimated fish trophic positions in each river. We observed a similar trophic structure in almost all low-productivity rivers. Detritus (allochthonous resources derived from riparian zone—CPOM and processed organic matter from upstream sources—FPOM) were important to sustain the fish assemblages, especially in smaller rivers. We also observed a growing consumption of autochthonous primary producers, algae and periphyton, with the increase in river dimensions and especially for primary consumers. Fishes from the smallest river occupied lower mean trophic positions; however, the assemblage exhibited wider food-chain length than those from larger rivers. Our results indicate an important role of autochthonous primary producers even in rivers with low nutrient concentrations. These results are important to increase the knowledge about medium-size oligotrophic rivers, especially because tropical rivers can support highly diverse fish assemblages and productive fisheries even exhibiting low in situ primary productivity. [ABSTRACT FROM AUTHOR]

ABSTRACT Perennial ryegrass is one of the most important food sources in animal production. However, several pests affect this crop, and one of the primary control strategies is the symbiotic relationships between ryegrass endophyte fungi. This fungus produces alkaloids that exhibit toxic activity against arthropods. Furthermore, the effect of fungi may extend to higher trophic levels, including predators (spiders and/or insects), decreasing their abundance and diversity. Given the importance of spiders and insects as predators, whether the symbiotic interaction between perennial ryegrass and endophyte fungus reduces the abundance and diversity of predators pose an important question. To address this question, natural enemies in perennial ryegrass were collected and analyzed over a year, and the percentage of endophyte fungus was evaluated by the presence of hyphae from two ryegrass cultivars, Jumbo (E-) and Alto AR1 (E+). We observed an 80% endophyte infection rate for (E+) and 0% for (E-). Moreover, 222 individual spiders corresponding to 10 families were identified in both perennial ryegrasses, including 209 individuals for (E-) and 13 for (E+). The most abundant spider family was Lycosidae, representing 71.17% of the total spiders. In addition, 65 insects were collected, corresponding to 6 families, with Carabidae being the most abundant. Furthermore, the Simpson index indicated the dominance of the family Lycosidae. Overall, spider and insect abundance and diversity were reduced in (E+), suggesting a negative effect of the endophyte on predator populations.

In many marine ecosystems worldwide, overfishing is a prominent cause in removing large predatory fishes from ecological communities. Fluctuation in the abundance of higher trophic level species can transform an ecosystem's structure and function by altering trophic interactions through density-mediated top-down control. Accordingly, understanding the extent to which humans indirectly influence a community through altering predator abundance is of critical importance. Thus, during the summer of 2013 and 2014 the impacts of fishing on the trophic structure of kelp forest fishes were examined within the Southern California Bight. In 2013, we tested whether decreased abundance through fishing for higher trophic level predators relieves predation pressure on lower trophic level prey. Using a combination of underwater survey techniques, density (no. fish/100 [m.sup.2]) and biomass (g/100 [m.sup.2]) of conspicuous fish species were sampled inside and outside of three long-standing Marine Protected Areas (MPAs) off La Jolla, Santa Catalina Island, and Anacapa Island, California. We found that the secondary carnivore and herbivore/omnivore trophic levels were significantly lower in density and biomass outside of MPAs. Inversely, the primary carnivore trophic level biomass was higher outside of MPAs. At the species level, we observed a lower abundance outside MPAs of large kelp bass (>25 cm) and higher densities of potential prey, kelp perch. Other primary carnivore fishes (blacksmith and senorita) showed a non-significant trend of higher biomass outside MPAs. Our results provide evidence of trophic level changes due to fishing pressure and provide support for a possible weakening of top-down control on specifically the kelp perch population through the removal of large kelp bass outside MPAs. The removal or recovery of predators can greatly influence an ecosystem. As more recent studies suggest that indirect community effects of fishing and protection can take up to decades to detect, it is necessary to document the continued changes on the structure, function, and dynamics of the kelp forests and rocky reefs off southern California., In marine ecosystems, fishing is the most exploitative anthropogenic influence on the abundance, biomass, and diversity of organisms within these communities (Jackson et al. 2001; Aburto-Oropeza et al. 2011; Zellmer [...]

The increase in plastic debris and its environmental impact has been a major concern for scientists. Physical destruction, chemical reactions, and microbial activity can degrade plastic waste into particles smaller than 5 mm, known as microplastics (MPs). MPs may eventually enter aquatic ecosystems through surface runoff. The accumulation of MPs in aquatic environments poses a potential threat to finfish, shellfish, and the ecological balance. This study investigated the effect of MP exposure on freshwater and marine fish. MPs could cause significant harm to fish, including physical damage, death, inflammation, oxidative stress, disruption of cell signalling and cellular biochemical processes, immune system suppression, genetic damage, and reduction in fish growth and reproduction rates. The activation of the detoxification system of fish exposed to MPs may be associated with the toxicity of MPs and chemical additives to plastic polymers. Furthermore, MPs can enhance the bioavailability of other xenobiotics, allowing these harmful substances to more easily enter and accumulate in fish. Accumulation of MPs and associated chemicals in fish can have adverse effects on the fish and humans who consume them, with these toxic substances magnifying as they move up the food chain. Changes in migration and reproduction patterns and disruptions in predator-prey relationships in fish exposed to MPs can significantly affect ecological dynamics. These interconnected changes can lead to cascading effects throughout aquatic ecosystems. Thus, implementing solutions like reducing plastic production, enhancing recycling efforts, using biodegradable materials, and improving waste management is essential to minimize plastic waste and its environmental impact. [Display omitted] • Plastic additives represent an additional source of aquatic pollution. • MPs absorb other pollutants altering their toxicity, bioavailability, and fate. • MPs and associated contaminants impair organisms, environments, and human health. [ABSTRACT FROM AUTHOR]

Seit 1950 sind sowohl die Artenvielfalt von Ackerunkräutern als auch die Arthropoden und Vögel in Deutschland und darüber hinaus stark zurückgegangen. Es stellt sich die Frage, welche Rolle Ackerunkräuter bei der Unterstützung der Artenvielfalt, insbesondere von Arthropoden und Vögeln, spielen. In einer Literaturrecherche wurden 51 Ackerunkrautarten und 3 Unkrautgattungen, welche in Deutschland häufig vorkommen, auf ihre Rolle als Nahrung und Lebensraum für die Fauna untersucht. Direkte und indirekte Verbindungen zwischen Ackerunkräutern und Vögeln sowie Arthropoden wurden anhand von Daten aus der veröffentlichten Literatur gezählt. Es wurden 5180 Verbindungen zwischen den Ackerunkräutern und Arthropoden bzw. Vögeln gefunden. Die Daten weisen darauf hin, dass Ackerunkräuter nicht nur die landwirtschaftliche Erzeugung behindern, sondern auch eine Vielzahl von Ökosystemleistungen unterstützen.

Keywords: biodiversity; biological carbon sequestration; ecosystem function; forest regeneration; Global Biodiversity Monitoring System; remote sensing; species richness; trophic levels EN biodiversity biological carbon sequestration ecosystem function forest regeneration Global Biodiversity Monitoring System remote sensing species richness trophic levels 5117 5119 3 08/17/23 20230915 NES 230915 Ecosystem studies often consider the co-benefits of biodiversity and carbon sequestration, but these carbon-biodiversity links can be complex and multifaceted. Biodiversity, ecosystem function, forest regeneration, Global Biodiversity Monitoring System, biological carbon sequestration, remote sensing, species richness, trophic levels This work serves as a cautionary tale for ongoing efforts to assess biodiversity and ecosystem function by using remote sensing, which is now widely employed for large-scale evaluations of both biological carbon sequestration and biodiversity. [Extracted from the article]

The framework of the plant economics spectrum advanced our understanding of plant ecology and proved as a unifying concept across plant taxonomy, growth forms and biomes. Similar approaches for animals mostly focus on linking life‐history and metabolic theories, but not on their application in ecosystem research. To fill this gap, we propose the animal economics spectrum (AES) based on broadly available traits that describe organismal size, biological times and rates.To exemplify the feasibility and general usefulness of constructing the AES, we compiled data on adult and offspring body mass, life span, age at first reproduction, reproductive and metabolic rate of 98 terrestrial taxa from seven selected animal classes and mapped these taxa into an exemplary quantitative trait space.The AES consists of two principal axes related to reproductive strategies and the pace of life; both axes are linked by animal metabolism. The AES thus closely mirrors seminal ideas on fundamental life‐history strategies and more recent discoveries and developments in the fields of life‐history and metabolic theories. Furthermore, we find associations between the positions of animals within the AES and taxonomy, thermoregulation and body plan.The AES shows that key dimensions describing different ecological strategies of animals can be depicted with functional traits that are relatively easily accessible for a broad spectrum of animal taxa. We suggest future steps towards an application of the AES in ecosystem research aiming at the understanding of ecological processes and ecosystem functions. Additionally, we urge for databases that compile comparable functional traits for a large proportion of animals, but also for further groups of organisms with the ultimate goal to map the economics spectrum of life.The framework of the AES will be relevant for understanding ecological processes across animal taxa at species, community and ecosystem levels. We further discuss how it can facilitate predictions on how the functional composition and diversity of animal communities can be affected by global change. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Stable isotope ratios of carbon (13C/12C) and nitrogen (15N/14N) in soft tissues of 41 abundant macrobenthic species from the continental slope of the Sea of Okhotsk were determined. The δ15N and δ13С values of invertebrate species and groups studied were highly variable, reflecting the diversity of their ratio compositions. The range of δ 15N values (from 6.8 to 18.3‰) corresponded to four trophic levels: from second (for detritivorous bivalve molluscs) to fifth (for some species of carnivorous gastropods and starfish). [ABSTRACT FROM AUTHOR]