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At least 91 records · Page 5Linked to original sources
USGS2002

Dynamics of the Lake Michigan food web, 1970-2000

Herein, we document changes in the Lake Michigan food web between 1970 and 2000 and identify the factors responsible for these changes. Control of sea lamprey ( Petromyzon marinus ) and alewife ( Alosa pseudoharengus ) populations in Lake Michigan, beginning in the 1950s and 1960s, had profound effects on the food web. Recoveries of lake whitefish ( Coregonus clupeaformis ) and burbot ( Lota lota ) populations, as well as the buildup of salmonine populations, were attributable, at least in part, to sea lamprey control. Based on our analyses, predation by salmonines was primarily responsible for the reduction in alewife abundance during the 1970s and early 1980s. In turn, the decrease in alewife abundance likely contributed to recoveries of deepwater sculpin ( Myoxocephalus thompsoni ), yellow perch ( Perca flavescens ), and burbot populations during the 1970s and 1980s. Decrease in the abundance of all three dominant benthic macroinvertebrate groups, including Diporeia , oligochaetes, and sphaeriids, during the 1980s in nearshore waters ( 50 m deep) of Lake Michigan, was attributable to a decrease in primary production linked to a decline in phosphorus loadings. Continued decrease in Diporeia abundance during the 1990s was associated with the zebra mussel ( Dreissena polymorpha ) invasion, but specific mechanisms for zebra mussels affecting Diporeia abundance remain unidentified.

Canadian Journal of Fisheries and Aquatic Sciences↗
USGS2019

Timber harvest alters mercury bioaccumulation and food web structure in headwater streams

Timber harvest has many effects on aquatic ecosystems, including changes in hydrological, biogeochemical, and ecological processes that can influence mercury (Hg) cycling. Although timber harvest’s influence on aqueous Hg transformation and transport are well studied, the effects on Hg bioaccumulation are not. We evaluated Hg bioaccumulation, biomagnification, and food web structure in 10 paired catchments that were either clear-cut in their entirety, clear-cut except for an 8-m wide riparian buffer, or left unharvested. Average mercury concentrations in aquatic biota from clear-cut catchments were 50% higher than in reference catchments and 165% higher than in catchments with a riparian buffer. Mercury concentrations in aquatic invertebrates and salamanders were not correlated with aqueous THg or MeHg concentrations, but rather treatment effects appeared to correspond with differences in the utilization of terrestrial and aquatic basal resources in the stream food webs. Carbon and nitrogen isotope data suggest that a diminished shredder niche in the clear-cut catchments contributed to lower basal resource diversity compared with the reference of buffered treatments, and that elevated Hg concentrations in the clear-cut catchments reflect an increased reliance on aquatic resources in clear-cut catchments. In contrast, catchments with riparian buffers had higher basal resource diversity than the reference catchments, indicative of more balanced utilization of terrestrial and aquatic resources. Further, following timber harvest THg concentrations in riparian songbirds were elevated, suggesting an influence of timber harvest on Hg export to riparian food webs. These data, coupled with comparisons of individual feeding guilds, indicate that changes in organic matter sources and associated effects on stream food web structure are important mechanisms by which timber harvest modifies Hg bioaccumulation in headwater streams and riparian consumers.

Oregon↗
USGS2023

Mercury isotope values in shoreline spiders reveal transfer of aquatic mercury sources to terrestrial food webs

The transfer of aquatic contaminants, including mercury (Hg), to terrestrial food webs is an often-overlooked exposure pathway to terrestrial animals. While research has implemented the use of shoreline spiders to assess aquatic to terrestrial Hg transfer, it is unclear whether Hg sources, estimated from isotope ratios, can be successfully resolved to inform site assessments and remedy effectiveness. To examine aquatic to terrestrial Hg transfer, we collected shoreline spiders ( Tetragnatha spp.) and aquatic insect larvae (suborder Anisoptera) across a mosaic of aquatic and shoreline habitats in the St. Louis River and Bad River, tributaries to Lake Superior. The fraction of industrial Hg in sediments was reflected in the δ 202 Hg values of aquatic dragonfly larvae and predatory fish, connecting benthic Hg sources to the aquatic food web. Shoreline spiders mirrored these aquatic Hg source signatures with highly positive correlations in δ 202 Hg between tetragnathids and dragonfly larvae ( r 2 = 0.90). Further assessment of different spider taxa (i.e., araneids and pisaurids) revealed that differences in prey consumption and foraging strategies resulted in isotope differences, highlighting the importance of spider taxa selection for Hg monitoring efforts.

Minnesota, Wisconsin↗
USGS2015

Changes in the Lake Michigan food web following dreissenid mussel invasions: A synthesis

Using various available time series for Lake Michigan, we examined changes in the Lake Michigan food web following the dreissenid mussel invasions and identified those changes most likely attributable to these invasions, thereby providing a synthesis. Expansion of the quagga mussel ( Dreissena rostriformis bugensis ) population into deeper waters, which began around 2004, appeared to have a substantial predatory effect on both phytoplankton abundance and primary production, with annual primary production in offshore (> 50 m deep) waters being reduced by about 35% by 2007. Primary production likely decreased in nearshore waters as well, primarily due to predatory effects exerted by the quagga mussel expansion. The drastic decline in Diporeia abundance in Lake Michigan during the 1990s and 2000s has been attributed to dreissenid mussel effects, but the exact mechanism by which the mussels were negatively affecting Diporeia abundance remains unknown. In turn, decreased Diporeia abundance was associated with reduced condition, growth, and/or energy density in alewife ( Alosa pseudoharengus ), lake whitefish ( Coregonus clupeaformis ), deepwater sculpin ( Myoxocephalus thompsonii ), and bloater ( Coregonus hoyi ). However, lake-wide biomass of salmonines, top predators in the food web, remained high during the 2000s, and consumption of alewives by salmonines actually increased between the 1980–1995 and 1996–2011 time periods. Moreover, abundance of the lake whitefish population, which supports Lake Michigan's most valuable commercial fishery, remained at historically high levels during the 2000s. Apparently, counterbalancing mechanisms operating within the complex Lake Michigan food web have enabled salmonines and lake whitefish to retain relatively high abundances despite reduced primary production.

Lake Michigan↗
USGS2024

Allochthonous marsh subsidies enhances food web productivity in an estuary and its surrounding ecosystem mosaic

Terrestrial organic matter is believed to play an important role in promoting resilient estuarine food webs, but the inherent interconnectivity of estuarine systems often obscures the origins and importance of these terrestrial inputs. To determine the relative contributions of terrestrial (allochthonous) and aquatic (autochthonous) organic matter to the estuarine food web, we analyzed carbon, nitrogen, and sulfur stable isotopes from multiple trophic levels, environmental strata, and habitats throughout the estuarine habitat mosaic. We used a Bayesian stable isotope mixing model (SIMM) to parse out relationships among primary producers, invertebrates, and a pelagic and demersal fish species (juvenile Chinook salmon and sculpin, respectively). The study was carried out in the Nisqually River Delta (NRD), Washington, USA, a recently-restored, macrotidal estuary with a diverse habitat mosaic. Plant groupings of macroalgae, eelgrass, and tidal marsh plants served as the primary base components of the NRD food web. About 90% of demersal sculpin diets were comprised of benthic and pelagic crustaceans that were fed by autochthonous organic matter contributions from aquatic vegetation. Juvenile salmon, on the other hand, derived their energy from a mix of terrestrial, pelagic, and benthic prey, including insects, dipterans, and crustaceans. Consequently, allochthonous terrestrial contributions of organic matter were much greater for salmon, ranging between 26 and 43%. These findings demonstrate how connectivity among estuarine habitat types and environmental strata facilitates organic matter subsidies. This suggests that management actions that improve or restore lateral habitat connectivity as well as terrestrial-aquatic linkages may enhance allochthonous subsidies, promoting increased prey resources and ecosystem benefits in estuaries.

Washington↗
USGS2015

Mercury and selenium accumulation in the Colorado River food web, Grand Canyon, USA

Mercury (Hg) and selenium (Se) biomagnify in aquatic food webs and are toxic to fish and wildlife. The authors measured Hg and Se in organic matter, invertebrates, and fishes in the Colorado River food web at sites spanning 387 river km downstream of Glen Canyon Dam (AZ, USA). Concentrations were relatively high among sites compared with other large rivers (mean wet wt for 6 fishes was 0.17–1.59 μg g –1 Hg and 1.35–2.65 μg g –1 Se), but consistent longitudinal patterns in Hg or Se concentrations relative to the dam were lacking. Mercury increased (slope = 0.147) with δ 15 N, a metric of trophic position, indicating biomagnification similar to that observed in other freshwater systems. Organisms regularly exceeded exposure risk thresholds for wildlife and humans (6–100% and 56–100% of samples for Hg and Se, respectfully, among risk thresholds). In the Colorado River, Grand Canyon, Hg and Se concentrations pose exposure risks for fish, wildlife, and humans, and the findings of the present study add to a growing body of evidence showing that remote ecosystems are vulnerable to long-range transport and subsequent bioaccumulation of contaminants. Management of exposure risks in Grand Canyon will remain a challenge, as sources and transport mechanisms of Hg and Se extend far beyond park boundaries. Environ Toxicol Chem 2015;9999:1–10

Arizona↗
USGS2006

Early Cretaceous terrestrial ecosystems in East Asia based on food-web and energy-flow models

In recent years, there has been global interest in the environments and ecosystems around the world. It is helpful to reconstruct past environments and ecosystems to help understand them in the present and the future. The present environments and ecosystems are an evolving continuum with those of the past and the future. This paper demonstrates the contribution of geology and paleontology to such continua. Using fossils, we can make an estimation of past population density as an ecosystem index based on food-web and energy-flow models. Late Mesozoic nonmarine deposits are distributed widely on the eastern Asian continent and contain various kinds of fossils such as fishes, amphibians, reptiles, dinosaurs, mammals, bivalves, gastropods, insects, ostracodes, conchostracans, terrestrial plants, and others. These fossil organisms are useful for late Mesozoic terrestrial ecosystem reconstruction using food-web and energy-flow models. We chose Early Cretaceous fluvio-lacustrine basins in the Choyr area, southeastern Mongolia, and the Tetori area, Japan, for these analyses and as a potential model for reconstruction of other similar basins in East Asia. The food-web models are restored based on taxa that occurred in these basins. They form four or five trophic levels in an energy pyramid consisting of rich primary producers at its base and smaller biotas higher in the food web. This is the general energy pyramid of a typical ecosystem. Concerning the population densities of vertebrate taxa in 1 km2 in these basins, some differences are recognized between Early Cretaceous and the present. For example, Cretaceous estimates suggest 2.3 to 4.8 times as many herbivores and 26.0 to 105.5 times the carnivore population. These differences are useful for the evaluation of past population densities of vertebrate taxa. Such differences may also be caused by the different metabolism of different taxa. Preservation may also be a factor, and we recognize that various problems occur in past ecosystem reconstructions. Counts of small numbers of confirmed species and estimates of maximum numbers of species present in the basin are used for the analysis and estimation of energy flow. This approach applies the methods of modern ecosystem analysis. ?? 2005 Elsevier Ltd. All rights reserved.

Cretaceous Research↗
USGS2016

Sea lamprey carcasses exert local and variable food web effects in a nutrient-limited Atlantic coastal stream

Resource flows from adjacent ecosystems are critical in maintaining structure and function of freshwater food webs. Migrating sea lamprey ( Petromyzon marinus ) deliver a pulsed marine-derived nutrient subsidy to rivers in spring when the metabolic demand of producers and consumers are increasing. However, the spatial and temporal dynamics of these nutrient subsidies are not well characterized. We used sea lamprey carcass additions in a small stream to examine changes in nutrients, primary productivity, and nutrient assimilation among consumers. Algal biomass increased 57%–71% immediately adjacent to carcasses; however, broader spatial changes from multiple-site carcass addition may have been influenced by canopy cover. We detected assimilation of nutrients (via δ 13 C and δ 15 N) among several macroinvertebrate families including Heptageniidae, Hydropsychidae, and Perlidae. Our research suggests that subsidies may evoke localized patch-scale effects on food webs, and the pathways of assimilation in streams are likely coupled to adjacent terrestrial systems. This research underscores the importance of connectivity in streams, which may influence sea lamprey spawning and elicit varying food web responses from carcass subsidies due to fine-scale habitat variables.

Canadian Journal of Fisheries and Aquatic Sciences↗
USGS2017

Food-web structure in canyon and slope-associated fauna revealed by stable isotopes

Food webs and associated trophic linkages among organisms are central themes in ecology that provide insight into the structure and function of ecosystems. In the deep sea, food webs rely on particulate flux raining from surface waters for energy (Klages et al. 2003), except for chemosynthetic communities, which rely on in situ production via chemosynthesis (Van Dover 2007). In general, the deep sea is a food limited environment because only a small percentage of organic carbon produced in surface waters settles to the seafloor (Gage and Tyler 1991, Klages et al. 2003, De La Rocha and Passow 2007). In contrast, relative to more quiescent slope environments, canyons can experience dynamic flow and turbulence. Internal tides can enhance turbulent mixing near the canyon seafloor leading to resuspension of sediments. Channeling of organic matter in deepsea canyons can enhance benthic productivity leading to high biodiversity (Vetter and Dayton 1998, 1999) and trophic complexity (Stefanescu et al. 1994, Cartes and Sorbe 1999). Thus, there may be a decoupling between the benthic-productivity relationships in canyon environments where food limitation may not be a driving factor influencing community structure. However, there have been only a few studies, often limited in depth range and spatial scale, that have examined the trophic pathways of deepsea canyons relative to adjacent slope environments (Duineveld et al. 2001, Fanelli et al. 2009, Cartes et al. 2010, Jeffreys et al. 2011).

OCS Study↗
USGS2009

Shifts in the trophic base of intermittent stream food webs

Understanding spatial and temporal variation in the trophic base of stream food webs is critical for predicting population and community stability, and ecosystem function. We used stable isotope ratios ( 13 C/ 12 C, and 15 N/ 14 N) to characterize the trophic base of two streams in the Ozark Mountains of northwest Arkansas, U.S.A. We predicted that autochthonous resources would be more important during the spring and summer and allochthonous resources would be more important in the winter due to increased detritus inputs from the riparian zone during autumn leaf drop. We predicted that stream communities would demonstrate increased reliance on autochthonous resources at sites with larger watersheds and greater canopy openness. The study was conducted at three low-order sites in the Mulberry River Drainage (watershed area range: 81-232 km 2 ) seasonally in 2006 and 2007. We used circular statistics to examine community-wide shifts in isotope space among fish and invertebrate consumers in relation to basal resources, including detritus and periphyton. Mixing models were used to quantify the relative contribution of autochthonous and allochthonous energy sources to individual invertebrate consumers. Significant isotopic shifts occurred but results varied by season and site indicating substantial variation in the trophic base of stream food webs. In terms of temporal variation, consumers shifted toward periphyton in the summer during periods of low discharge, but results varied during the interval between summer and winter. Our results did not demonstrate increased reliance on periphyton with increasing watershed area or canopy openness, and detritus was important at all the sites. In our study, riffle-pool geomorphology likely disrupted the expected spatial pattern and stream drying likely impacted the availability and distribution of basal resources.

Hydrobiologia↗
USGS2004

Modeling selenium bioaccumulation through arthropod food webs in San Francisco Bay, California, USA

Trophic transfer is the main process by which upper trophic level wildlife are exposed to selenium. Transfers through lower levels of a predator's food web thus can be instrumental in determining the threat of selenium in an ecosystem. Little is known about Se transfer through pelagic, zooplankton‐based food webs in San Francisco Bay ([SFB], CA, USA), which serve as an energy source for important predators such as striped bass. A dynamic multipathway bioaccumulation model was used to model Se transfer from phytoplankton to pelagic copepods to carnivorous mysids ( Neomysis mercedis ). Uptake rates of dissolved Se, depuration rates, and assimilation efficiencies (AE) for the model were determined for copepods and mysids in the laboratory. Small (73‐250 μm) and large (250‐500 μm) herbivorous zooplankton collected from SFB ( Oithona/Limnoithona and Acartia sp.) assimilated Se with similar efficiencies (41‐52%) from phytoplankton. Mysids assimilated 73% of Se from small herbivorous zooplankton; Se AE was significantly lower (61%) than larger herbivorous zooplankton. Selenium depuration rates were high for both zooplankton and mysids (12‐25% d −1 ), especially compared to bivalves (2‐3% d −1 ). The model predicted steady state Se concentrations in mysids similar to those observed in the field. The predicted concentration range (1.5‐5.4 μg g −1 ) was lower than concentrations of 4.5 to 24 μg g −1 observed in bivalves from the bay. Differences in efflux between mysids and bivalves were the best explanation for the differences in uptake. The results suggest that the risk of selenium toxicity to predators feeding on N. mercedis would be less than the risk to predators feeding on bivalves. Management of selenium contamination should include food webs analyses to focus on the most important exposure pathways identified for a given watershed.

California↗
USGS2015

The rapid return of marine-derived nutrients to a freshwater food web following dam removal

Dam removal is increasingly being recognized as a viable river restoration action. Although the main beneficiaries of restored connectivity are often migratory fish populations, little is known regarding recovery of other parts of the freshwater food web, particularly terrestrial components. We measured stable isotopes in key components to the freshwater food web: salmon, freshwater macroinvertebrates and a river specialist bird, American dipper ( Cinclus mexicanus ), before and after removal of the Elwha Dam, WA, USA. Less than a year after dam removal, salmon returned to the system and released marine-derived nutrients (MDN). In that same year we documented an increase in stable-nitrogen and carbon isotope ratios in American dippers. These results indicate that MDN from anadromous fish, an important nutrient subsidy that crosses the aquatic–terrestrial boundary, can return rapidly to food webs after dams are removed which is an important component of ecosystem recovery.

Washington↗
USGS2019

Linking demographic and food-web models to understand management trade-offs

Alternatives in ecosystem-based management often differ with respect to trade-offs between ecosystem values. Ecosystem or food-web models and demographic models are typically employed to evaluate alternatives, but the approaches are rarely integrated to uncover conflicts between values. We applied multi-state models to a capture-recapture dataset on common guillemots Uria aalge breeding in the Baltic Sea to identify factors influencing survival. The estimated relationships were employed together with Ecopath-with-Ecosim food-web model simulations to project guillemot survival under six future scenarios incorporating climate change. The scenarios were based on management alternatives for eutrophication and cod fisheries, issues considered top priority for regional management, but without known direct effects on the guillemot population. Our demographic models identified prey quantity (abundance and biomass of sprat Sprattus sprattus) as the main factor influencing guillemot survival. Most scenarios resulted in projections of increased survival, in the near (2016-2040) and distant (2060-2085) future. However, in the scenario of reduced nutrient input and precautionary cod fishing, guillemot survival was projected to be lower in both future periods due to lower sprat stocks. Matrix population models suggested a substantial decline of the guillemot population in the near future, 24% per 10 years; and a smaller reduction, 1.1% per 10 years, in the distant future. To date, many stakeholders and Baltic Sea governments have supported reduced nutrient input and precautionary cod fishing and implementation is underway. Negative effects on non-focal-species have previously not been uncovered, but our results show that the scenario is likely to negatively impact the guillemot population. Linking model results allowed identifying trade-offs associated with management alternatives. This information is critical to thorough evaluation by decision-makers, but not easily obtained by food-web models or demographic models in isolation. Appropriate datasets are often available, making it feasible to apply a linked approach for better-informed decisions in ecosystem-based management.

Ecology and Evolution↗
USGS2007

Application of information theory methods to food web reconstruction

In this paper we use information theory techniques on time series of abundances to determine the topology of a food web. At the outset, the food web participants (two consumers, two resources) are known; in addition we know that each consumer prefers one of the resources over the other. However, we do not know which consumer prefers which resource, and if this preference is absolute (i.e., whether or not the consumer will consume the non-preferred resource). Although the consumers and resources are identified at the beginning of the experiment, we also provide evidence that the consumers are not resources for each other, and the resources do not consume each other. We do show that there is significant mutual information between resources; the model is seasonally forced and some shared information between resources is expected. Similarly, because the model is seasonally forced, we expect shared information between consumers as they respond to the forcing of the resources. The model that we consider does include noise, and in an effort to demonstrate that these methods may be of some use in other than model data, we show the efficacy of our methods with decreasing time series size; in this particular case we obtain reasonably clear results with a time series length of 400 points. This approaches ecological time series lengths from real systems.

Ecological Modelling↗
USGS2010

Dreissenid mussels are not a "dead end" in Great Lakes food webs

Dreissenid mussels have been regarded as a “dead end” in Great Lakes food webs because the degree of predation on dreissenid mussels, on a lakewide basis, is believed to be low. Waterfowl predation on dreissenid mussels in the Great Lakes has primarily been confined to bays, and therefore its effects on the dreissenid mussel population have been localized rather than operating on a lakewide level. Based on results from a previous study, annual consumption of dreissenid mussels by the round goby (Neogobius melanostomus) population in central Lake Erie averaged only 6 kilotonnes (kt; 1 kt = one thousand metric tons) during 1995–2002. In contrast, our coupling of lake whitefish (Coregonus clupeaformis) population models with a lake whitefish bioenergetics model revealed that lake whitefish populations in Lakes Michigan and Huron consumed 109 and 820 kt, respectively, of dreissenid mussels each year. Our results indicated that lake whitefish can be an important predator on dreissenid mussels in the Great Lakes, and that dreissenid mussels do not represent a “dead end” in Great Lakes food webs. The Lake Michigan dreissenid mussel population has been estimated to be growing more than three times faster than the Lake Huron dreissenid mussel population during the 2000s. One plausible explanation for the higher population growth rate in Lake Michigan would be the substantially higher predation rate by lake whitefish on dreissenid mussels in Lake Huron.

Journal of Great Lakes Research↗
USGS2023

Can spatial food web subsidies associated with river hydrology and lateral connectivity be detected using stable isotopes?

During and following lateral connections, aquatic organisms residing in the river channel may assimilate material from sources imported from oxbows, and oxbow residents may consume and assimilate material imported from the channel. Hydrology, lateral connectivity, and stable isotope ratios of fishes and mussels were analyzed for evidence of spatial food web subsidies between the active channel and oxbow lakes in the floodplain of the Guadalupe River, Texas. During surveys conducted between March 2016 and April 2017, fish, mussel, periphyton, seston, and riparian plant samples were collected in and around two oxbows and adjacent channel sites for analysis of stable isotope ratios. Biplots of δ 13 C and δ 15 N were graphed for basal sources and specimens of six common fish species, four sunfish species ( Lepomis spp. combined), and two mussel species (Unionidae combined) captured from oxbows and the channel. Within each graph, polygons were drawn to indicate the space occupied by animals that could have assimilated feasible combinations of source materials originating from either oxbows or the river channel. Based on positions of animals within source polygons, riparian C4 grasses were not an important source of organic matter supporting biomass of fishes and mussels within the channel or oxbows. Overall, 84% of organisms had isotopic signatures consistent with assimilation of in situ sources, but also 76% of all organisms were inconclusive with regards to cross-habitat exchanges. Outliers that may have assimilated ex situ source material were observed for only 4% of 313 organisms from oxbows and 9% of 232 organisms from the channel, and some but not all of these cases followed high flow pulses that connected oxbows for extended periods. Several issues that compromise inferences from stable isotope analysis were identified, and estimation of spatial food web subsidies in fluvial systems could be enhanced by analyzing additional biomarkers, such as isotopic ratios of other elements and compound-specific stable isotopes, as well as additional sources, time-specific biotracers, and experimental approaches that directly track movement of sources and organisms in spatially structured food webs.

Texas↗
USGS2009

Methylmercury enters an aquatic food web through acidophilic microbial mats in Yellowstone National Park, Wyoming

Microbial mats are a visible and abundant life form inhabiting the extreme environments in Yellowstone National Park (YNP), WY, USA. Little is known of their role in food webs that exist in the Park's geothermal habitats. Eukaryotic green algae associated with a phototrophic green/purple Zygogonium microbial mat community that inhabits low-temperature regions of acidic (pH ∼ 3.0) thermal springs were found to serve as a food source for stratiomyid (Diptera: Stratiomyidae) larvae. Mercury in spring source water was taken up and concentrated by the mat biomass. Monomethylmercury compounds (MeHg + ), while undetectable or near the detection limit (0.025 ng l −1 ) in the source water of the springs, was present at concentrations of 4–7 ng g −1 dry weight of mat biomass. Detection of MeHg + in tracheal tissue of larvae grazing the mat suggests that MeHg + enters this geothermal food web through the phototrophic microbial mat community. The concentration of MeHg + was two to five times higher in larval tissue than mat biomass indicating MeHg + biomagnification occurred between primary producer and primary consumer trophic levels. The Zygogonium mat community and stratiomyid larvae may also play a role in the transfer of MeHg + to species in the food web whose range extends beyond a particular geothermal feature of YNP.

Wyoming↗
USGS2012

More than a meal: integrating non-feeding interactions into food webs

Organisms eating each other are only one of many types of well documented and important interactions among species. Other such types include habitat modification, predator interference and facilitation. However, ecological network research has been typically limited to either pure food webs or to networks of only a few (<3) interaction types. The great diversity of non-trophic interactions observed in nature has been poorly addressed by ecologists and largely excluded from network theory. Herein, we propose a conceptual framework that organises this diversity into three main functional classes defined by how they modify specific parameters in a dynamic food web model. This approach provides a path forward for incorporating non-trophic interactions in traditional food web models and offers a new perspective on tackling ecological complexity that should stimulate both theoretical and empirical approaches to understanding the patterns and dynamics of diverse species interactions in nature.

Ecology Letters↗