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123 results for “bottom-up”
Variation in the relative effects of top-down and bottom-up forces on herbivores and herbivory along an elevational gradient in the southern Appalachian mountains in 2001
It is a well established fact that top-down (predation), bottom-up (resource availability) and lateral (interference) interactions are the dominant biotic forces in terrestrial ecosystems in addition to a host of other interactions like mutualism and symbiosis. The primary emphasis has always been to look for a singular mechanistic explanation in determining community dynamics. The ecological literature is replete with controversy on the subject of whether top-down or bottom-up forces predominate in ecosystems and their role in dynamics of ecological communities. The emerging consensus is that both top-down and bottom-up forces act in concert and the impetus is shifting towards the elucidation of the context, biotic and abiotic, under which these forces come into play. There are very few studies that have addressed this question and looked at the simultaneous interaction of these forces. I propose to study the effects of spatial heterogeneity in biotic and abiotic factors along an elevation gradient on the relative impacts of top-down and bottom-up forces and the result of their interactive effects on folivory. Specifically, I shall address the effects of spatial variation in plant quality and predation pressure and their interactive impacts on insect herbivore biomass and consumption. I shall also address the effects of complexity within/among trophic levels on the impact of these forces. The study aims to bring about a greater understanding of the role played by abiotic factors and complexity in community dynamics.
Dataset of 'Search for top-down and bottom-up drivers of latitudinal trends in insect herbivory in oak trees in Europe'
<p>This file correspond to the dataset that has being used in the article ‘Search for top-down and bottom-up drivers of latitudinal trends in insect herbivory in oak trees in Europe’ by Elena Valdés-Correcher et al. in Global Ecology and Biogeography.</p>
Legacy effect of grazing intensity mediates the bottom-up controls of resource addition on soil food webs
<p>1. Large-scale studies have demonstrated that nitrogen (N) and water (W) availability greatly affect terrestrial ecosystems worldwide, and this is especially true for the resource-poor semi-arid grasslands. Yet, experimental evidence is lacking for how N and W availability affect soil food webs across historical grazing intensity-altered environments at a local scale.</p> <p>2. Here, we included N- and W-addition treatments in an 8-year grazing experiment (with four grazing intensities) to determine how the legacy effects of grazing intensity mediate the responses of key components of soil food webs (plants, microorganisms, and nematodes) to resource addition in a semi-arid grassland.</p> <p>3. After 4 years of N- and W-addition treatments (with no grazing during that 4-year period), we found that a legacy of grazing, even light grazing, had significant negative effects on the components of plant community and soil food webs. Both N and W addition increased above- and below-ground plant biomass, especially under moderate and heavy grazing. N addition had negative effects on the biomass of bacteria under no grazing, while W addition increased the biomass of actinomycetes under light grazing. N addition decreased the abundance of omnivorous + carnivorous nematodes under light and heavy grazing, while W addition increased their abundance under heavy grazing. Overall, the effects of resource addition on soil food webs progressively decreased from the lowest trophic level (primary producers, i.e., plants), to intermediate tropic levels (microorganisms and root-feeding nematodes), to higher trophic levels (microbial-feeding nematodes and omnivorous + carnivorous nematodes).</p> <p>4. Synthesis and applications. Our results, which are the first data concerning the effects of resource addition on key components of soil food webs across a historical grazing-induced environmental gradient, show that the strong bottom-up controls of resource addition on soil food webs are mediated by the legacy of grazing intensity. These finding should be useful for predicting the responses of grassland ecosystems to future climate change and suggest that the recovery of degraded grasslands will require more than restoration measure of resource inputs alone.</p>
Data from: Disturbance-mediated consumer assemblages determine fish community structure and moderate top-down influences through bottom-up constraints
<ol> <li>Disturbance is a strong structuring force that can influence the strength of species interactions at all trophic levels, but controls on the contributions to community structure of top-down and bottom-up processes across such gradients remain poorly understood. Changes in the composition of predator and consumer assemblages, and their associated traits, across gradients of environmental harshness (e.g., flooding) are likely to be a particularly important influence on the strength of top-down control and may drive bottom-up constraints.</li> <li>We examined how consumers with particular traits, and the predators that consumed them, varied across a gradient of stream flooding disturbance and used experiments to assess the predation impact on those contrasting consumer communities (ultimately quantifying how flood disturbance altered the strength of top-down control).</li> <li>Consumer community composition and mobility were strongly related to flood disturbance; the biomass and drift of protected primary consumers (i.e., those with morphological defences) decreased with increasing flood disturbance. Predatory fish species had different disturbance niches, and path analysis identified that both direct flood-disturbance effects and indirect bottom-up constraints of flood-disturbance on consumers influenced predatory fish composition and biomass. Fishes generally fed most effectively on consumer types associated with their particular niche, but all fishes were strongly size-selective when feeding on protected consumers. Although protected consumers did not grow large enough to escape predation, an <i>in situ </i>experiment showed protected consumers were at a reduced risk of predation as disturbance increased compared to unprotected consumers.</li> <li>Overall, top-down control declined with flood disturbance, but the effect depended on consumer traits. Predatory fishes were only capable of exerting top-down control on protected consumers in benign habitats but impacted unprotected consumers across a larger range of the disturbance gradient. Collectively our findings suggest that a shift towards a more disturbed state will probably result in reduced predator impacts and a weakening of top-down control. Moreover, predicted increases in the frequency and intensity of climatic events causing disturbance, such as flooding, are likely to result in a community shift that disproportionately impacts protected consumers and the predators that utilise them as prey through the subsequent bottom-up constraints.</li> </ol>
Bottom-up when it is not top-down: Predators and plants control biomass of grassland arthropods
1) We investigate where bottom-up and top-down control regulates ecological communities as a mechanism linking ecological gradients to the geography of consumer abundance and biomass. We use standardized surveys of 54 North American grasslands to test alternate hypotheses predicting 100-fold shifts in the biomass of four common grassland arthropod taxa—Auchenorrhyncha, sucking herbivores, Acrididae, chewing herbivores, Tettigoniidae, omnivores, and Araneae, predators. 2) Bottom-up models predict that consumer biomass tracks plant quantity (e.g. productivity and standing biomass) and quality (nutrient content) and that ectotherm access to food increases with temperature. Each of the focal trophic groups responded differently to these drivers: the biomass of sucking herbivores and omnivores increased with plant biomass; that of chewing herbivores tracked plant quality; and predator biomass did not depend on plant quality, plant quantity, or temperature. 3) The exploitation ecosystem hypothesis (EEH) is a top-down hypothesis that predicts a shift from resource limitation of herbivores when plant production is low, to predator limitation when plant production is high. In grasslands where spider biomass was low, herbivore biomass increased with plant biomass, whereas bottom-up structuring was not evident when spiders were abundant. Furthermore, neither predator biomass nor trophic position (via stable isotope analysis) increased with plant biomass, suggesting predators themselves are top-down limited. 4) Stable isotope analysis revealed that trophic position of the chewing herbivore and omnivore increased significantly with plant biomass, suggesting these groups increased scavenging and meat consumption in grasslands with higher carbohydrate availability. 5) Taken together, our snapshot sampling documents gradients of food web structure across 54 grasslands, consistent with multiple hypotheses of bottom-up and top-down regulation. 10-Jan-2020
Evaluating bottom-up forcing of a rocky intertidal resource harvest on a high trophic-level consumer group
<p>The importance of ecosystem-based management (EBM) frameworks for resource harvest has increased over the past several decades as ecosystems face numerous anthropogenic stressors. In these frameworks, resource managers must consider the suite of interactions that comprise food webs and how resource harvest drives responses in non-target organisms. In rocky intertidal zones along North Atlantic coastlines, rockweed (<em>Ascophyllum nodosum</em>)—a canopy-forming brown seaweed—has been commercially harvested for centuries, yet most research on the effects of harvest have focused on the responses of the target resource and the macroinvertebrate assemblage. In this study, we used a Before-After Control-Impact experiment to assess the bottom-up effects of commercial rockweed harvest on a high trophic-level consumer group (birds) in Maine (USA). Overall, there was no evidence for strong bottom-up forcing of rockweed harvest on birds' site visitation. There was a small (fewer than two birds) positive effect size of harvest during the one-year post-harvest recovery interval. Several of the trends observed for the full bird assemblage appear to be driven more strongly by the low tide than the high tide bird assemblage. Independent of treatment, site visitation by birds was low in our study (60% of surveys recorded no birds) and highlights questions about the use of rocky intertidal habitats relative to other habitat types in coastal birds' home ranges. To our knowledge, there are no comparable assemblage-level bird studies in this system that can provide context to our results. Further research on coastal birds' habitat use within home ranges and food-web connections with rockweed-associated macroinvertebrates is needed to more confidently incorporate this high trophic-level consumer group into an EBM framework for a rocky intertidal resource harvest.</p>
Vertical stratification of leaf physical traits exerts bottom-up pressures on insect herbivory in a sugar maple temperate forest
<p>Do vertical gradients in temperate forest structure insect herbivore communities? We tested the hypothesis that the increase in light intensity from understory to forest canopy level drives differences in leaf physical traits and budburst phenology that impact insect herbivores and thus play a role in structuring both herbivore communities and the leaf damages they cause. Twelve sugar maple <em>(Acer saccharum)</em> sites were monitored in southern Quebec, examining insect herbivore patterns from understory to the shaded and sun canopy over the summers of 2020, 2021, and 2022. Additionally, we recorded leaf physical traits, temperature, humidity, and sun exposure. Our findings revealed that leaf thickness increased along the vertical gradient in 2021, making leaves less favorable to herbivores in the canopy level. Accordingly, we recorded a consistent decrease in insect herbivory damage rates from the understory to the shaded canopy and sun canopy in 2020 and 2021, driven by leaf cutters, skeletonizers, stipplers, and leaf miners. These results support our hypothesis that variation in plant physical traits due to sun exposure contributes to the vertical stratification of insect damage. In 2022, the gradient of insect herbivore abundance corroborated the observed damage trends from the previous years. Moreover, we calculated an average annual herbivory rate of 9.1% of the leaf surface in our study site, suggesting limited evidence supporting a significant contribution of background herbivory to the decline of sugar maple forests. Overall, our study highlights the importance of vertical gradients in structuring insect herbivore communities and emphasizes the role of leaf traits in mediating these interactions.</p>
A bottom-up coarse-grained model for interactions of lipids with TiO2 nanoparticles
<p>Supplemetary information data to the paper:</p> <p>M.Ivanov and A.P.Lyubartsev, "Development of a bottom-up coarse-grained model for interactions of lipids with TiO<br> nanoparticles", J. Comput. Chem.m 2024. Doi: <a href="https://doi.org/10.1002/jcc.27310">10.1002/jcc.27310</a></p>
Bottom-up effect of host protective symbionts on parasitoid diversity: Limited evidence from two field experiments
<p>1. Protective symbionts can provide effective and specific protection to their hosts. This protection can differ between different symbiont strains with each strain providing protection against certain components of the parasite and pathogen community their host faces. Protective symbionts are especially well known from aphids where, among other functions, they provide protection against different parasitoid wasps. However, most of the evidence for this protection comes from laboratory experiments.</p> <p>2. Our aim was to understand how consistent protection is across different symbiont strains under natural field conditions and whether symbiont diversity enhanced the species diversity of colonizing parasitoids, as could be expected from the specificity of their protection.</p> <p>3. We used experimental colonies of the black bean aphid, Aphis fabae, to investigate symbiont conferred protection under natural field conditions over two seasons. Colonies differed only in their symbiont composition, carrying either no symbionts, a single strain of the protective symbiont Hamiltonella defensa, or a mixture of three H. defensa strains. These aphid colonies were exposed to natural parasitoid communities in the field. Subsequently, we determined the parasitoids hatched from each aphid colony.</p> <p>4. The evidence for a protective effect of H. defensa was limited and inconsistent between years, and aphid colonies harboring multiple symbiont strains did not support a more diverse parasitoid community. Instead, parasitoid diversity tended to be highest in the absence of H. defensa.</p> <p>5. Symbiont conferred protection, although a strong and repeatable effect under laboratory conditions, may not always cause the predicted bottom-up effects under natural conditions in the field.</p>
Data related to: Bottom-up effects of fungicides on tadpoles of the European common frog (Rana temporaria)
<p>We have uploaded a range of files informding about ergosterol and bacteria levels on leaf litter (LeafMicrobes.xlsx); the feces production, leaf consumption and legnth development of tadpoles during the study and among the two experimental phases as detailed in the mansucript (FecesFeedingLength.xlxs); composition of fatty acids in tadpoles and leaf litter (NFLA.xlxs); metamophoses event (Metamorphosis.xlsx)</p> <p> </p> <p>Paper abstract as submitted:</p> <p><span><span><span><span><span><span><span><span><span><span><span>Biodiversity is under pressure world-wide, with amphibians being particularly threatened. Stressors related to human activity, such as chemicals, are contributing to this decline. It remains, however, unclear whether chemicals exhibiting a fungicidal activity could indirectly affect tadpoles, that depend on microbially conditioned leaf litter as food source. The indirect effect of fungicides (sum concentration of a fungicide mixture composed of azoxystrobin, carbendazim, crybrodinil, quinoxifen and tebuconcazole: 100 µg/L) on tadpoles was assessed relative to leaf litter colonised by microbes in absence of fungicides (control) and a worst case scenario, that is leached leaf litter without microbial colonisation. The quality of leaf litter as food for tadpoles of the European common frog (<i>Rana temporaria</i>) was characterised through neutral lipid fatty acid profiles and microbial sum parameters and verified by sublethal responses in tadpoles (i.e. feeding rate, feces production, growth and fatty acid composition). Fungicides changed the nutritious quality of leaf litter likely through alterations in leaves' neutral lipid fatty acid profiles (i.e., changes in some physiologically important highly unsaturated fatty acids reached more than 200%) in combination with a potential adsorption onto leaves during conditioning. These changes were reflected by differences in the development of tadpoles ultimately resulting in an earlier start of metamorphosis. Our data provide a first indication that fungicides potentially affect tadpole development indirectly through bottom-up effects. This pathway is so far not addressed in fungicide environmental risk assessment and merits further attention.</span></span></span></span></span></span></span></span></span></span></span></p>
Bottom-up effects of plant quantity and quality on arthropod diversity across multiple trophic levels in a semi-arid grassland
<p><span>1. </span><span>Plant quantity and quality can independently affect the diversity of the entire arthropod communities and multiple arthropod taxa in grassland ecosystems. However, it remains unclear how these effects on arthropod taxa at one trophic level propagate through food web to influence the diversity of higher trophic levels.</span></p> <p><span>2. </span><span>We performed a monoculture experiment with 15 herbaceous species in the Inner Mongolian grassland to investigate how natural variations in plant productivity and host leaf traits affect herbivore taxon richness, which in turn affects predator taxon richness.</span></p> <p><span>3. </span><span>For herbivores, plant productivity indirectly promoted herbivore taxon richness by increasing herbivore biomass, which was attributed to the increases in the richness of dominant sucking herbivores and endophytes</span> <span>with high food requirements. However, the high plant quality indicator (e.g. high leaf protein, phosphorus and water contents, and high leaf protein to carbohydrate ratio) directly increased, whereas the low plant quality indicator (e.g. high leaf lignin content) directly decreased herbivore taxon richness. Taxon richness of chewing and sucking herbivores with specific feeding modes (tearing or sucking mouthparts) showed strong positive responses to increas</span><span>ing</span><span> plant quality.</span></p> <p><span>4. </span><span>For predators, herbivore taxon richness, rather than herbivore biomass, mainly mediated the positive effects of plant productivity and the high plant quality indicator, but the negative effect of the low plant quality indicator, on predator taxon richness. At the feeding guild level, the taxon richness of parasitoids, other predators and spiders exhibited positive responses to different herbivores, which was attributed to their different diet preferences. Predator diversity could be promoted by prey partitioning among predator guilds facilitating species coexistence. At the family level, the taxon richness of most predator families was positively correlated with that of more than one herbivore family, suggesting that high predator diversity may </span><span>be caused by balanced diets owing to high prey diversity.</span></p> <p><span>5. Synthesis</span><span>.</span><span> Natural variations in plant quantity and quality can substantially affect the diversity of herbivores and cascade up the food web to affect predators. Specificity and mechanisms of feeding have a large impact on the responses of arthropod guilds at each trophic level.</span></p>
Bottom-up Fabrication of 2D Rydberg Exciton Arrays in Cuprous Oxide
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Data mining antibody sequences for database searching in bottom-up proteomics
<p>Mass spectrometry (MS)-based proteomics is a powerful method for identifying and quantifying antibodies. Among the various MS approaches, bottom-up proteomics is especially effective for analyzing thousands of antibodies in complex mixtures. In this method, proteins are enzymatically digested into smaller peptides, typically using the protease trypsin, which are then analyzed via mass spectrometry. These peptides are matched to sequences in standard databases like UniProt or NCBI-RefSeq for identification.</p> <p>However, a major limitation of this approach is the absence of comprehensive disease-specific antibody databases. Current databases, such as UniProt, include only a fraction of the antibody sequences present in the human body. For instance, as of January 2024, UniProt contains just 38,800 immunoglobulin sequences, far short of the billions of antibodies the human immune system can produce. As a result, relying on such limited databases can lead to under-detection of antibodies, particularly those associated with specific diseases. Expanding antibody databases with disease-specific sequences is crucial for improving the accuracy of MS-based proteomics in identifying antibodies relevant to human health.</p> <p>Recently, through next-generation sequencing of antibody gene repertoires, it has become possible to obtain billions of antibody sequences (in amino acid format) by annotating, translating, and numbering antibody gene sequences. These large numbers of sequences are now available in public databases such as the <a href="https://opig.stats.ox.ac.uk/webapps/oas/" rel="nofollow">Observed Antibody Space</a>. We hypothesize that using these theoretical antibody sequences as new databases for bottom-up proteomics could address the current lack of antibody coverage in standard databases.</p> <p>We developed a workflow to create disease-specific antibody peptide databases for bottom-up proteomics. The workflow details are available on <a href="https://github.com/trinhxt/SDU_Immunoinformatics">GitHub</a>. The database and metadata files generated by this workflow are stored in this Zenodo dataset, and they are used in DAT-DB — a web application that allows researchers to obtain FASTA files of disease-specific antibody peptides for direct use in bottom-up proteomics (see <a href="https://trinhxt.shinyapps.io/DAT-DB/">Demo version</a>).</p> <p>Each database file in this dataset is in <em>.duckdb</em> format and contains tables with 10 columns: Sequence, Filename, Patient, BSource, BType, Isotype, N_patient, N_antibody, Length_aa, and CDR3. The "<strong>Sequence</strong>" column contains tryptic peptides. "<strong>Filename</strong>" is the file where the data was collected. "<strong>Patient</strong>" refers to the patient number as listed in <em>metadata2.csv</em>. "<strong>BSource</strong>" refers to the B-cells' source, and "<strong>BType</strong>" refers to the type of B-cells. "<strong>Isotype</strong>" specifies the antibody isotype (IgA, IgD, IgE, IgG, IgM, or Bulk). "<strong>N_patient</strong>" indicates the number of patients having this peptide, and "<strong>N_antibody</strong>" specifies the number of antibodies containing this peptide. "<strong>Length_aa</strong>" indicates the number of amino acids in the peptide, while "<strong>CDR3</strong>" shows whether the peptide is found in the CDR3 region.</p> <p>The file <em>metadata1.csv</em> contains information about each database file, while <em>metadata2.csv</em> provides details about the sources of the collected antibodies.</p>
Helminth-associated changes in host immune phenotype connect top-down and bottom-up interactions during co-infection
<p>Within-host parasite interactions can be mediated by the host and changes in host phenotypes often serve as indicators of the presence or intensity of parasite interactions.</p> <p>Parasites like helminths induce a range of physiological, morphological, and immunological changes in hosts that can drive bottom-up (resource-mediated) or top-down (immune-mediated) interactions with co-infecting parasites. Although top-down and bottom-up interactions are typically studied in isolation, the diverse phenotypic changes induced by parasite infection may serve as a useful tool for understanding if, and when, these processes act in concert.</p> <p>Using an anthelmintic treatment study of African buffalo (Syncerus caffer), we tracked changes in host immunological and morphological phenotypes during helminth-coccidia co-infection to investigate their role in driving independent and combinatorial bottom-up and top-down parasite interactions. We also examined repercussions for host fitness.</p> <p>Clearance of a blood-sucking helminth, Haemonchus, from the host gastrointestinal tract induced a systemic Th2 immune phenotype, while clearance of a tissue-feeding helminth, Cooperia, induced a systemic Th1 phenotype. Furthermore, the Haemonchus-associated systemic Th2 immune phenotype drove simultaneous top-down and bottom-up effects that increased coccidia shedding by changing the immunological and morphological landscapes of the intestine.</p> <p>Higher coccidia shedding was associated with lower host body condition, a lower chance of pregnancy, and older age at first pregnancy, suggesting that coccidia infection imposed significant condition and reproductive costs on the host.</p> <p>Our findings suggest that top-down and bottom-up interactions may commonly co-occur and that tracking key host phenotypes that change in response to infection can help uncover complex pathways by which parasites interact.</p>
Integrating top-down and bottom-up approaches to understand the genetic architecture of speciation across a monkeyflower hybrid zone
<p><span>Understanding the phenotypic and genetic architecture of reproductive isolation is a longstanding goal of speciation research. In several systems, large-effect loci contributing to barrier phenotypes have been characterized, but such causal connections are rarely known for more complex genetic architectures. In this study, we combine 'top-down' and 'bottom-up' approaches with demographic modeling toward an integrated understanding of speciation across a monkeyflower hybrid zone. Previous work suggests that pollinator visitation acts as a primary barrier to gene flow between two divergent red- and yellow-flowered ecotypes of <em>Mimulus</em> <em>aurantiacus</em>. Several candidate isolating traits and anonymous SNP loci under divergent selection have been identified, but their genomic positions remain unknown. Here, we report findings from demographic analyses that indicate this hybrid zone formed by secondary contact, but that subsequent gene flow was restricted by widespread barrier loci across the genome. Using a novel, geographic cline-based genome scan, we demonstrate that candidate barrier loci are broadly distributed across the genome, rather than mapping to one or a few 'islands of speciation.' Quantitative trait locus (QTL) mapping reveals that most floral traits are polygenic, with little evidence that QTL co-localize, indicating that most traits are genetically independent. Finally, we find little evidence that QTL and candidate barrier loci overlap, suggesting that some loci contribute to other forms of reproductive isolation. Our findings highlight the challenges of understanding the genetic architecture of reproductive isolation and reveal that barriers to gene flow aside from pollinator isolation may play an important role in this system.</span></p>
Habitat isolation interacts with top-down and bottom-up processes in a seagrass ecosystem
<p>Habitat loss is accelerating at unprecedented rates, leading to the emergence of smaller, more isolated habitat remnants. Habitat isolation adversely affects many ecological processes independently, but little is known about how habitat isolation may interact with ecosystem processes such as top-down (consumer-driven) and bottom-up (resource-driven) effects. To investigate the interactive influence of habitat isolation, resource availability and consumer distribution and impact on community structure, we tested two hypotheses using invertebrate and algal epibionts on temperate seagrasses, an ecosystem of ecological and conservation importance. First, we hypothesized that habitat isolation will change the structure of the seagrass epibiont community, and isolated patches of seagrass will have lower epibiont biomass and different epibiont community composition. Second, we hypothesized that habitat isolation would mediate top-down (i.e., herbivory) and bottom-up (i.e., nutrient enrichment) control for algal epibionts. We used observational studies in natural seagrass patches, and experimental artificial seagrass to examine three levels of habitat isolation. We further manipulated top-down and bottom-up processes in artificial seagrass through consumer reductions and nutrient additions, respectively. We indeed found that habitat isolation of seagrass patches decreased epibiont biomass and modified epibiont community composition. This pattern was largely due to dispersal limitation of invertebrate epibionts that resulted in a decline in their abundance and richness in isolated patches. Further, habitat isolation reduced consumer abundances, weakening top-down control of algal epibionts in isolated seagrass patches. Nutrient additions, however, reversed this pattern, and allowed a top-down effect on algal richness to emerge in isolated habitats, demonstrating a complex interaction between patch isolation and top-down and bottom-up processes. Habitat isolation may therefore shape the relative importance of central processes in ecosystems, leading to changes in community composition and food web structure in marine habitats.</p>
Top-down vs. bottom-up: Grazing and upwelling regime alter patterns of primary productivity in a warm-temperate system
<p>Community structure is driven by biological interactions and physical processes that can vary across environmental gradients and spatial scales. Early ecological models focused on the role of resource availability (i.e. bottom-up effects), predicting that the strength of top-down control varied along gradients of primary productivity and that local species interactions determined community structure. However, the role of regional scale oceanographic processes in determining species interactions and community structure is now widely recognized, with bottom-up effects such as coastal upwelling driving regional scale patterns of resource availability. Such nutrient subsidies can significantly alter primary production and drive changes in algae-herbivore interactions in rocky intertidal habitats. However, despite the potential for upwelling to alter these interactions, studies investigating the effects of upwelling and grazing pressure are scarce, particularly for warm-temperate systems, and generally cover narrow geographical ranges. Using in-situ herbivore exclusion experiments replicated across multiple upwelling regimes, we investigated the effects of both grazing pressure and upwelling, as well as their interactions, on the sessile invertebrate community and primary production of macroalgal communities in a warm-temperate system. Invertebrate cover remained consistently low at upwelling sites and was reduced at non-upwelling sites when grazers were excluded. Macroalgal cover was greater at upwelling sites when grazers were excluded and there was a strong effect of succession throughout the experimental period. Grazing pressure was greater at upwelling sites, particularly during winter months. There was a non-significant trend towards greater grazing pressure on early than later successional stages. Our results show that the positive impacts of bottom-up effects of nutrient supply on algal production do not overwhelm top-down control in this warm-temperate system. We speculate that global increases in air and sea-surface temperatures in warm-temperate systems will promote top-down effects in upwelling regions by increasing herbivore metabolic and growth rates.</p>
Helminth-associated changes in host immune phenotype connect top-down and bottom-up interactions during co-infection
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Bottom-up effect of host protective symbionts on parasitoid diversity: Limited evidence from two field experiments
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Data related to: Bottom-up effects of fungicides on tadpoles of the European common frog (Rana temporaria)
Open the record for dataset details and reuse information.
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Allen Brain Atlas
Allen Brain Atlas is an Allen Institute collection of brain map atlases, datasets, APIs, and analysis tools covering mouse, human, and non-human primate brain resources.
Annotated Behaviour and Observability Dataset (ABODe)
ABODe is a University of Edinburgh DataShare dataset for behavior classification in group-housed mice using home-cage video, identities, bounding boxes, ground-plate positions, and annotator labels.
DANDI Archive for NWB datasets
DANDI is a BRAIN Initiative archive for publishing and sharing neurophysiology data, including electrophysiology, optophysiology, and behavioral data packaged as NWB and related standards.
International Brain Laboratory public data
The International Brain Laboratory public data releases expose standardized mouse decision-making experiments, including Neuropixels recordings, widefield calcium imaging, behavior, and session metadata accessed through the ONE API.
OpenNeuro
OpenNeuro is a free, open platform for sharing neuroimaging datasets, with public search, dataset pages, and download paths for web, S3, DataLad, and the OpenNeuro CLI.