Biodiminution of lithium in forest floor food webs.

Forest ecosystems are vital for sustaining biodiversity, and tree-dwelling snakes, as integral parts of forest food webs, are extremely sensitive to environmental alterations caused by deforestation. The goal of this study is to explore how deforestation influences the way treedwelling snakes in southern forests untilize their habitats. Through field investigations and data analysis, we found that deforestation led to a substantial reduction in canopy cover, directly decreasing the available habitat area for tree-dwelling snakes. The simplified vegetation structure, such as the decline in understory vegetation and hollow trees, impaired their foraging and reproductive abilities. Furthermore, the simplification of vegetation structure—such as fewer understory plants and hollow trees—impairs the snakes’ capacity to find food and reproduce. Additionally, habitat fragmentation resulting from deforestation restricted their movement range and gene flow. This research not only enhances our comprehension of the ecological consequences of deforestation but also provides a scientific foundation for formulating targeted conservation strategies for tree-dwelling snakes and their habitats.

Global biogeochemical cycling of trace elements is under influences of anthropogenic inputs and climate change, and their trophic transfers within natural food webs are not yet fully characterized. The present study investigated the trophodynamics of four trace elements (essential: copper and zinc, and non-essential: arsenic and cadmium) in a river food web and compared those with an upland forest food web in a semi-remote watershed in northern California, United States. We found empirical evidence of biomagnification for copper, zinc, and cadmium in the lower trophic levels of both aquatic and terrestrial food webs while we showed biodiminution for arsenic in food webs within the river, but not the forest as shown by calculating Trophic Magnification Factor (TMF), a direct and robust approach to explore the biomagnification efficiency of trace elements along the food web. There was a positive intercorrelation between copper, zinc, and cadmium among the food web components, indicating potential common mechanisms in controlling the trophic transfer of these three cationic trace elements in the natural food webs.

Riverine songbirds capture high levels of atmospheric mercury pollution from brown food webs in forests by mercury isotopic evidence.

Effects of biopedturbation by European badger Meles meles on the forest soil food web persist for years as revealed by nematode indicators

Temporal and spatial variations of soil nematode assemblages across distinct forest ecosystems

Abstract The introduction of non‐native tree species has become a global concern and may disrupt native communities and related ecosystem functions. Soil food webs regulate organic matter decomposition and nutrient cycling in forests with their feeding activities, but evaluating consequences of the introduction of tree species on soil invertebrates is challenging due to the complex trophic structure and wide range in body size of soil invertebrates. Here, we employed an energetic food web approach and estimated the energy flux in soil food webs using a four‐node model including soil meso‐ and macrofauna decomposers and predators. We examined pure and mixed stands of native European beech (Fagus sylvatica), introduced Douglas fir (Pseudotsuga menziesii) and native range‐expanding Norway spruce (Picea abies) across site conditions. Compared to native forests, introduced tree species reduced total fresh mass of macrofauna predators by 92% at sandy sites but not that of decomposers, suggesting trophic downgrading in soil food webs by Douglas fir. The energy flux in mixed forests was intermediate between respective monocultures, suggesting that tree mixtures mitigate potential negative impacts of introduced tree species on food web functioning. Across size classes, soil macrofauna responded more sensitively to changes in environmental conditions than soil mesofauna. Additionally, total energy flux positively correlated with species richness, pointing to the significance of soil biodiversity for trophic functionality. The energy flux through mesofauna outweighed that through macrofauna when considering energy loss to predators, highlighting the importance of mesofauna for decomposition processes in forest soil food webs. Overall, the study emphasizes the critical role of tree species composition, site conditions and soil biodiversity in driving energy flux through soil food webs and maintaining forest ecosystem functions. Read the free Plain Language Summary for this article on the Journal blog.

Distinct food-web transfers of 137Cs to fish in river and lake ecosystems: A case study focusing on masu salmon in the Fukushima evacuation zone

The Influence of Management Practice on the Snakes in Forest Food Webs

Anthropogenic activities in disturbance-mediated ecosystems might affect certain ecological processes that, in turn, can affect the stability and resilience of those ecosystems. In upland pine forests, land-use practices such as intensive silviculture and fire suppression have contributed to the loss of diversity-rich pine savannahs throughout the southeast. Whereas the application of management strategies has been shown to alter forest structure in pine ecosystems, less is known about how these efforts influence pathways of energy flow and the consumer–resource relationships therein. Here, we investigated the effects of frequency of forest management on the trophic structure and resource use of snake communities in two pine forests under high and low frequencies of management (i.e., shorter fire return intervals and thinning versus longer fire return intervals and limited thinning). We sampled snakes, prey, and dominant basal resources across each site for three summers from 2018 to 2020. Using stable isotope analysis, we compared community-wide metrics of trophic structure and generated isotopic mixing models to determine the relative contribution of resources to snake consumers. We found that the high-frequency site supported an increased diversity of snake species, and that species exhibited increased trophic redundancy. The low-frequency site supported fewer snake species that relied on a wider range of resources, and occupied a wider range of relative tropic positions. Mixing models of consumer–resource relationships, and prey relative abundance, indicated that snakes were more generalized in their resource use in the high-frequency site, and utilized a broader diversity of prey more evenly. In contrast, snakes in the low-frequency site were more specialized in their prey use. We suggest that anthropogenic activities mimicking natural disturbances can drive food-web structure in these forest ecosystems. Increased frequency of forest management practices such as prescribed fires and thinning operations might support snake species diversity while also increasing trophic redundancy. Consequently, such management applications can lead to greater stability and resilience in pine-forest ecosystems. Our research further highlights the importance of ecological restoration that incorporates food-web perspectives to ensure the health of pine ecosystems.

Kelp forest food webs as hot spots for the accumulation of microplastic and polybrominated diphenyl ether pollutants

Fungi are organisms that enrich the diversity of living things in the plant world. Macroscopic fungi significantly affect the forest food web, the survival or germination of saplings, tree growth, and the overall health of the forest. Ganoderma has been widely cultivated in various countries due to its benefits as a medicine which is known to have the ability to treat hypertension, hyperglycemia, acute bronchitis, hepatitis, leukopenia, and arteriosclerosis. Research on mushrooms is still very minimally documented, so this research needs to be done. This study aims to identify the types of macroscopic fungi of the ganodermataceae that exist in Martelu Purba Nature Reserve. This study uses a direct survey method in the field. This method can be done by exploring in an area. Based on the research results, 6 types of macroscopic fungi from the Ganoderma family were obtained, namely Amauroderma rude, Cymatoderma elegans, Ganoderma applanatum, Ganoderma adspersum, Ganoderma pfeifferi, and Ganoderma boninense. The six types of mushrooms come from 3 genera, namely Amauroderma, Cymatoderma, and Ganoderma. Each type has different morphological characteristics which are the basis for distinguishing them. The potential utilization of Ganoderma has now been widely developed in the medical world

Abstract Motion‐sensitive cameras are commonly used to monitor wildlife occupancy rates; however, few studies have assessed whether data from cameras are correlated with density estimates obtained from more traditional labor‐intensive methods such as those based on capture‐mark‐recapture. We used data from a boreal forest community to test whether camera data were correlated with densities estimated from independent monitoring methods. We placed 72 covert cameras in the forest around Lhù'ààn Mân' (Kluane Lake), Yukon, Canada, for 7 years and tracked changes in population densities by camera hit rates. We independently estimated population densities of snowshoe hares (Lepus americanus) and red squirrels (Tamiasciurus hudsonicus) using capture‐mark‐recapture via live trapping, and Canada lynx (Lynx canadensis), coyotes (Canis latrans), and moose (Alces americanus) by snow track transects. Density estimates obtained from conventional aerial surveys were also periodically available for moose. Except for red squirrels, camera hit rates were highly correlated with population density estimates obtained by traditional methods, including across a large range of estimated densities corresponding to cyclic population dynamics in several species. Accordingly, we infer that motion‐sensitive cameras could supplement or replace traditional methods for monitoring key species in boreal forest food webs. Using cameras to monitor population change has several advantages; they require less effort in the field, are non‐invasive compared to live‐trapping, include multiple species at the same time, and rely less on weather than either aerial surveys or snow track transects. Tracking changes across the vast boreal forest is becoming increasingly necessary because of climate and landscape change and our data validate the use of motion‐sensitive cameras to provide a useful quantitative method for state‐of‐the‐environment reporting.

Cadmium accumulation in organisms from a spruce plantation amended with wood ash - an environmental risk?

Modified SEIB-DGVM enables simulation of masting in a temperate forest

Fertilization and combustion of fossil fuels have increased nitrogen (N) deposition over the last decades. Most boreal forests are N-limited; thus, increased N availability may have considerable implications for boreal forest food web structure and functioning. Soil biota are important drivers of ecosystem processes through their effect on carbon (C) and nutrient cycling. Among these, nematodes are ubiquitous in soil and respond quickly to environmental changes. They are thus useful in determining changes in ecosystem status. Boreal forest plants produce large quantities of condensed tannins (hereafter tannins), and these may decrease following N addition. As defence compounds, tannins may alter soil community structure by reducing microbial activity and deter microfauna. Using nematodes as indicators, we here investigated the linkages between N-induced changes in soil food web and soil tannin concentration. We utilized an experimental site where N has been added since 2003 at a rate of ca. 37 kg N ha−1 year−1. This have resulted in a shift in the understory, and consequently a 23 % lower soil tannin concentration. Fertilization led to a less structured nematode community dominated by bacterivores. Channel Index was 35 % lower in fertilized plots, indicating an increasing decomposition dominance by bacteria. Furthermore, the dominance of bacteria appears to have been inhibited by soil tannin concentrations in the fertilized plots. Overall, our study demonstrate that soil community structure strongly changes upon increased N availability, and lower soil tannin concentrations further facilitate the dominance of bacteria.

Acidification can have broad effects on forest ecosystems, ranging from consequences for individual organisms to alterations in trophic dynamics. While the effects of acidification on certain aspects of forest ecosystems have been well studied, less is known about the influence of soil acidification on the forest floor food web that includes amphibians and invertebrates. We investigated the effects of acidification on the American Toad (Anaxyrus americanus) and its interaction with the forest floor invertebrate community. We evaluated survival, growth, and diet of newly metamorphosed toads placed in terrestrial enclosures in forest plots with either experimentally elevated soil pH or untreated, acidified soils. We also conducted invertebrate pitfall sampling in these two soil pH types to evaluate the trophic interactions between toads and invertebrates. Toad mass after 90 days tended to be larger in plots with elevated soil pH, although survival and diet did not differ between soil pH types. We found no effect of soil pH on invertebrate abundances nor overall invertebrate diversity. We also found no evidence that toads exhibited top-down control of the invertebrate community. Collectively, our results indicate that acidified soils did not affect forest floor trophic dynamics. The presence of temporary enclosures we constructed, however, significantly reduced invertebrate abundances and overall diversity. Thus, the strong effect these structures can have on invertebrate communities should be considered when used in future studies.

ABSTRACT Eurasian red squirrels Sciurus vulgaris have unusually high δ 13C values compared to other forest rodents, which is seemingly related to the consumption of 13C-enriched conifer seeds. To test this hypothesis, we analyzed the hair of wild and zoo-kept red squirrels, seeds of pine and spruce, and feathers of specialized and opportunistic consumers of conifer seeds, crossbills Loxia spp., and woodpeckers Dendrocopos major. Data on the isotopic composition (δ 13C and δ 15N values) of hair or feathers of other species of forest rodents and birds were obtained from published studies. The range of mean δ 13C values of hair of wild forest rodents (19 species) exceeded 10 ‰. All squirrel species had high 13C content, S. vulgaris having maximum δ 13C values. In contrast, S. vulgaris kept in captivity had an isotopic composition similar to other captive rodents. The feathers of crossbills were enriched in 13C compared to other forest birds (15 species), while seeds of coniferous trees often had higher δ 13C values compared to seeds of other woody plants. Distinctiveness of the isotopic composition of mammals and birds feeding on the seeds of coniferous trees suggests that this resource can be traced through the entire forest food web.

Spiders play a key role in forest food webs, where they regulate decomposer populations and may act as predators of pests and disease vectors. Spider community composition is determined in part by vegetation structure. Therefore, the exclusion of large mammals, such as deer and wild boar, through wildlife fencing may affect the composition of spider communities and their prey in forest ecosystems. Web-building spiders and their prey were hand-collected in plots that had been fenced for three years, as well as adjacent unfenced plots in a mixed temperate forest in north-eastern Germany. Additionally, spiders in the leaf litter were sampled in fenced and unfenced subareas by sieving litter. Wildlife fencing did not significantly affect spider densities or community composition per microhabitat. However, fencing affected the cover of different microhabitats significantly as there was a higher density of larger trees and higher leaflitter cover in fenced plots while there was a higher percentage of bare ground and deadwood in unfenced plots. Spider communities and their prey composition differed significantly between microhabitats (deciduous trees, coniferous trees, dead wood, understory vegetation, leaf litter) independent of fencing. Thysanoptera prey was mainly caught by spiders on coniferous trees and in the understory vegetation. Heteroptera prey were captured most frequently in the understory vegetation while Hymenoptera (excl. Formicidae) prey were mostly caught on deciduous trees. Several spider species showed a preference between deciduous and coniferous trees in the mixed forest. Wildlife fencing alters the vegetation structure of mixed forests and has indirect effects on spider communities and their role in forest food webs due to alteration of microhabitat availability.

AimOur goal was to quantify nitrogen flows and stocks in green–brown food webs in different ecosystems, how they differ across ecosystems and how they respond to nutrient enrichment.LocationGlobal.Time periodContemporary.Major taxa studiedPlants, phytoplankton, macroalgae, invertebrates, vertebrates and zooplankton.MethodsData from >500 studies were combined to estimate nitrogen stocks and fluxes in green–brown food webs in forests, grasslands, brackish environments, seagrass meadows, lakes and oceans. We compared the stocks, fluxes and metabolic rates of different functional groups within each food web. We also used these estimates to build a dynamical model to test the response of the ecosystems to nutrient enrichment.ResultsWe found surprising symmetries between the green and brown channels across ecosystems, in their stocks, fluxes and consumption coefficients and mortality rates. We also found that nitrogen enrichment, either organic or inorganic, can disrupt this balance between the green and brown channels.Main conclusionsLinking green and brown food webs reveals a previously hidden symmetry between herbivory and detritivory, which appears to be a widespread property of natural ecosystems but can be disrupted by anthropogenic nitrogen additions.