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Blooms of marine phytoplankton fix complex pools of dissolved organic matter (DOM) that are thought to be partitioned among hundreds of heterotrophic microbes at the base of the food web. While the relationship between microbial consumers and phytoplankton DOM is a key component of marine carbon cycling, microbial loop metabolism is largely understood from model organisms and substrates. Here, we took an untargeted approach to measure and analyze partitioning of four distinct phytoplankton-derived DOM pools among heterotrophic populations in a natural microbial community using a combination of ecogenomics, stable isotope probing (SIP), and proteomics. Each 13C-labeled exudate or lysate from a diatom or a picocyanobacterium was preferentially assimilated by different heterotrophic taxa with specialized metabolic and physiological adaptations. Bacteroidetes populations, with their unique high-molecular-weight transporters, were superior competitors for DOM derived from diatom cell lysis, rapidly increasing growth rates and ribosomal protein expression to produce new relatively high C:N biomass. Proteobacteria responses varied, with relatively low levels of assimilation by Gammaproteobacteria populations, while copiotrophic Alphaproteobacteria such as the Roseobacter clade, with their diverse array of ABC- and TRAP-type transporters to scavenge monomers and nitrogen-rich metabolites, accounted for nearly all cyanobacteria exudate assimilation and produced new relatively low C:N biomass. Carbon assimilation rates calculated from SIP data show that exudate and lysate from two common marine phytoplankton are being used by taxonomically distinct sets of heterotrophic populations with unique metabolic adaptations, providing a deeper mechanistic understanding of consumer succession and carbon use during marine bloom events.

Central place foraging pollinators tend to develop multi-destination routes (traplines) to exploit patchily distributed plant resources. While the formation of traplines by individual pollinators has been studied in detail, how populations of foragers use resources in a common area is an open question, difficult to address experimentally. We explored conditions for the emergence of resource partitioning among traplining bees using agent-based models built from experimental data of bumblebees foraging on artificial flowers. In the models, bees learn to develop routes as a consequence of feedback loops that change their probabilities of moving between flowers. While a positive reinforcement of movements leading to rewarding flowers is sufficient for the emergence of resource partitioning when flowers are evenly distributed, the addition of a negative reinforcement of movements leading to unrewarding flowers is necessary when flowers are patchily distributed. In environments with more complex spatial structures, the negative experiences of individual bees on flowers favour spatial segregation and efficient collective foraging. Our study fills a major gap in modelling pollinator behaviour and constitutes a unique tool to guide future experimental programs.

Resource partitioning, and especially dietary partitioning, is a mechanism that has been studied for several canid species as a means to understand competitive relationships and the ability of these species to coexist. Coyotes ( Canis latrans ) and gray foxes ( Urocyon cinereoargenteus ) are two canid species that are widely distributed, in Mexico, and they are sympatric throughout most of their distribution range. However, trophic dynamic and overlap between them have not been thoroughly studied. In order to better understand their ecological relationship and potential competitive interactions, we studied the trophic niche overlap between both canids in a temperate forest of Durango, Mexico. The results are based on the analysis of 540 coyote and 307 gray fox feces collected in 2018. Both species consumed a similar range of food items, but the coyote consumed large species while the gray fox did not. For both species, the most frequently consumed food categories throughout the year and seasonally were fruit and wild mammals (mainly rodents and lagomorphs). Coyotes had higher trophic diversity in their annual diet ( H’ = 2.33) than gray foxes ( H’ = 1.80). When analyzing diets by season, trophic diversity of both species was higher in winter and spring and tended to decrease in summer and autumn. When comparing between species, this parameter differed significantly during all seasons except for summer. Trophic overlap throughout the year was high ( R 0 = 0.934), with seasonal variation between R 0 = 0.821 (autumn) and R 0 = 0.945 (spring). Both species based their diet on the most available food items throughout each season of the year, having high dietary overlap which likely can lead to intense exploitative competition processes. However, differences in trophic diversity caused by differential prey use can mitigate competitive interactions, allowing these different sized canid species to coexist in the study area.

Investigating resource partitioning of marine predators is essential for understanding coexistence of sympatric species and the functional role they play in marine ecosystems. Baleen whales are a key component of sub-Antarctic ecosystems, foraging predominantly on zooplankton and small forage fish. During the twentieth century, baleen whales were unsustainably exploited across the Southern Ocean. Within the exclusive economic zone of South Georgia and the South Sandwich Islands (SGSSI EEZ) in the South Atlantic, approximately 98,000 fin whales (Balaenoptera physalus) and 16,000 sei whales (B.borealis) were harvested. Despite both species historically occurring in high numbers and feeding in sub-polar waters, little is known about the mechanisms of coexistence. Here, by measuring stable isotope ratios of carbon (δ13C) and nitrogen (δ15N) in archived baleen plates and analysing historic catch data, we investigate resource partitioning of fin and sei whale during the commercial whaling period. Temporal and spatial occupancy at SGSSI EEZ (inferred from whaling catches that occurred between 1904 and 1976), alongside historic stomach contents (from the literature), and δ13C and δ15N results (observed in this study), suggests that despite using a common prey resource there was limited overlap in isotopic niches between the two species, with sei whales using SGSSI waters later in the season and for a shorter period than fin whales. We hypothesise that the isotopic differences were most likely due to sei whales foraging at lower latitudes prior to arrival at SGSSI. Our data provide novel insight into how two sympatric whale species co-occurring at SGSSI during the commercial whaling period may have partitioned resources and provide a potential ecological baseline to assess changes in resource use in recovering whale populations.

Across the northern hemisphere, ungulates are expanding in range and abundance, forming novel communities in increasingly human‐modified landscapes. These shifts drive new interactions over available food resources, but patterns of resource use and partitioning in Europe's multi‐species systems remain poorly understood. This study examined seasonal diets and resource partitioning in diverse cervid communities (moose, roe deer, red deer, and fallow deer) across two Swedish landscapes (coastal‐boreal and boreo‐nemoral) differing in deer density and land use. Based on their foraging strategies, we expected (Hypothesis 1) diet richness and dietary niche width to be greater in intermediate feeders (red and fallow deer) than in browsers (moose and roe deer), (Hypothesis 2) trophic partitioning between browsers and intermediate feeders to be driven mainly by graminoid use, and (Hypothesis 3) intra‐ and interspecific overlap to vary with season, deer density, habitat diversity, and proportion of arable land. DNA metabarcoding of 2568 fecal samples showed that deer consumed plants from over 70 families, though diets were typically dominated by fewer than 10. Vaccinium shrubs were key forages year‐round, while birch and willow dominated during the growing season. Moose consumed large amounts of pine in spring and winter (> 50% in the boreo‐nemoral, 35%–40% in the coastal‐boreal landscape), with less during summer‐autumn (~15%). Forbs were important for smaller deer, especially in spring and summer‐autumn, and more heavily used in winter in the boreo‐nemoral landscape, likely due to supplementary feeding with human‐provided food like hay or silage. Spruce use was low overall (< 5%), with fallow deer showing the highest intake. Consistent with Hypothesis 1, diet richness and niche width increased from moose to fallow deer. In partial support of Hypothesis 2, principal coordinates analysis (PCoA) revealed that graminoids contributed to trophic partitioning, but the pattern was not a strict browser–intermediate feeder divide. Moose consistently separated from the smaller deer due to avoidance of graminoids and reliance on pine and juniper, while roe deer, although a browser, sometimes overlapped with red and fallow deer through greater use of graminoids. During winter in the coastal‐boreal landscape, wavy hairgrass (Avenella flexuosa) contributed to the significant separation between browsing roe deer and intermediate‐feeding red deer diets, consistent with Hypothesis 2. Diet overlap among smaller deer varied with season and landscape. Intraspecific overlap was the highest in moose and the lowest in fallow deer, declining during summer–autumn across species. Overlap was influenced by deer density, habitat diversity, and arable land, consistent with Hypothesis 3, but effects were species‐specific and explained only limited variation. Our results highlight the dietary plasticity of red and fallow deer, which may intensify resource competition with moose and roe deer in multi‐species systems, particularly where supplementary feeding is common. These insights support adaptive, multi‐species management of deer in northern ecosystems. We used DNA metabarcoding of 2,568 fecal samples to examine seasonal diets and resource partitioning among four deer species (moose, roe deer, red deer, fallow deer) across two Swedish landscapes. Deer consumed a wide range of plants, but diets were typically dominated by a few key taxa, with distinct dietary separation between moose and smaller deer. Results reveal species‐specific plasticity and seasonal shifts in resource use, emphasizing the need for adaptive, multi‐species management in changing northern ecosystems.

Bacteria are ubiquitous on the Earth, and many use chemotaxis to colonise favourable microenvironments. The colonisation process is continuous, where animals, plants, protists, viruses and chemical and physical factors frequently remove bacteria from wide volume ranges. Colonisation processes are poorly understood in natural communities. Here, we investigated niche partitioning during colonisation in aquatic microbial communities using bands of bacterial chemotaxis in petri dishes from mixed-species communities. The community partitioned into loiterers, primary and secondary colonisers, each having distinct abundances and taxonomy. Within marine samples, Shewanella dominated the primary colonisers, whilst Enterobacteriaceae dominated this group within the freshwater samples. Whether the success of these specific groups translates to what occurs within natural communities is uncertain, but here we show these taxa have the capacity to colonise new, unexplored environments. A strong negative association existed between the primary colonisers and viral abundance, suggesting that successful colonisers simultaneously move toward areas of heightened resources, which correlated with lower virus-like particles. Here, we show that microbial communities constantly sort themselves into distinct taxonomic groups as they move into new environments. This sorting during colonisation may be fundamental to microbial ecology, industry, technology, and disease development by setting the initial conditions that determine the winners as a community develops.

Energy sources and trophic interactions among vent fauna were investigated in deep-sea hydrothermal vents in the North Fiji Basin (NFB), Southwest Pacific, using stable sulfur, carbon, and nitrogen isotopes. A Bayesian isotope mixing model (MixSIAR) was used to quantify the proportions of energy sources for symbiont-bearing taxa. Based on these results, symbionts of host taxa such as the hairy snail Alviniconcha boucheti, black snail Ifremeria nautilei, and vent mussel Bathymodiolus sp. showed different carbon fixation pathways or nutrient preferences. We also observed niche partitioning among the omnivores by utilizing different resources or by occupying different microhabitats. For example, the squat lobster Munidopsis spp. occupied the bottom part of the chimney where dead shells were scattered around, as it was predatory to mussels. The scale worm Branchinotogluma segonzaci exploited energy from particulate organic matter or free-living bacteria on the chimney, whereas shrimp Rimicaris variabilis, which were clustered around I. nautilei and Echionelamus ohtai communities, had isotopic compositions similar to them. In contrast, limpets attached to I. nautilei did not share resources with snails and derived energy from mixed carbon sources. Among the vent fauna that we sampled, the crab was the top predator in the NFB, possibly consuming everything but with a lower preference for mussels. Overall, we found a non-overlapping diet or spatial niche of the vent fauna, with each taxon having a unique source or metabolism, or proportion. Such diversification in resource use may play an important role in sustaining the coexistence of species in a small area.

Assessment of resource partitioning in pollinators at a particular place can be used to conserve plant communities by minimizing their inter-specific competition. Current study was conducted to investigate the occurrence of this phenomenon among plant communities under sub-tropical conditions for the first time in Pakistan. We considered the entire available flowering plant and floral visitor communities in the study area—Lal Suhanra forest of Bahawalpur, Pakistan- along with different variations among them based on morphology, color and symmetry (functional groups) i.e. four functional groups among insects and nine among plants. Weekly floral visitor censuses were conducted during spring season -from the first week of March to the fourth week of May 2018. Thirty individuals of each plant species -in bloom- were observed for floral visitors in each census. Plant species with different floral shapes, colors and symmetry did not show any significant resource partitioning. The Non-metric multidimensional scaling analysis followed by one-way ANOSIM test showed non- significant differences among all the pair of floral shapes, colors (except white and yellow) and symmetry (R-value < 0.168). However, SIMPER test suggested that flies were the most common group that contributed more towards within group similarities of different floral shapes (19 to 21% similarity), colors (16 to 30%) and symmetry (19%) followed by long-tongue bees i.e. 14 to 21%, 9 to 19% and 18%, respectively. Our results suggest that plant communities under sub-tropical conditions of Pakistan exhibit a generalist pollination system with no significant resource partitioning in pollinator species. Therefore, plant communities may have high competition for pollinator species which exhibits fewer implications of species loss on overall pollination process. Our study provides the basis for understanding the partitioning of pollinator guilds under sub-tropical conditions. Future studies should focus on functional traits in more detail at the community and the population scales for their possible impact on resource partitioning.

Exploring host preference and resource partitioning among seed predator species is essential for understanding the coexistence mechanisms and guiding effective forest pest management. This study aimed to elucidate how seed traits influence infestation dynamics and species interactions, focusing on acorn weevils infesting Quercus mongolica. Species identification and clarification of their evolutionary relationships within the Curculio genus were performed through phylogenetic analyses of the mitochondrial cytochrome c oxidase subunit I gene sequences. The seed infestation patterns were assessed by comparing the infestation rates across various seed size classes. Furthermore, the correlations between the seed morphological traits (length, width, aspect ratio, and weight) and weevil abundance were analyzed. The phylogenetic results revealed well-supported monophyletic clades corresponding to Curculio arakawai and Curculio sikkimensis. This confirmed the clear genetic separation between these two distinct weevil species, thereby substantiating the divergence observed in weevil populations correlated with different seed hosts. The infestation patterns revealed the association of weevil species-specific preferences with seed size: C. arakawai predominantly infested larger acorn seeds, whereas C. sikkimensis predominantly infested smaller acorn seeds. C. sikkimensis favored smaller ones. Both species exhibited positive correlations between abundance and seed length and width in larger seeds; however, the seed weight displayed no significant effect. These results indicate niche differentiation mediated by seed size and morphology, which likely reduced interspecific competition and facilitated coexistence. This study elucidates species-specific host selection patterns in acorn weevils and highlights acorn traits as crucial factors shaping seed predator assemblages. The findings provide valuable insights for developing targeted pest management strategies and supporting sustainable oak forest regeneration.

Soil phosphorus (P) partitioning could contribute to species diversity and structure in plant communities, but field-scale evidence for P partitioning remains scarce. We hypothesized that the presence of P partitioning could be inferred from statistical associations between the spatial distributions of plants and chemical forms of bioavailable soil P. We investigated this in a diverse tropical tree community on Barro Colorado Island, Panama. We quantified potentially bioavailable forms of soil P by extraction in 2 mM citric acid followed by treatment with phosphatase enzymes. We then linked these P forms to the distribution of 189 tree species in a 50 ha forest dynamics plot by testing species–P associations against null models of random dispersal. We found that 20% of tree species were significantly (α = 0.05) associated with the depletion of at least one soil organic P fraction, although around half of these associations might be false rejections of the null hypothesis due to type I error. Species in the Fabaceae (legumes), which are known to express high rates of phosphatase in their roots, were most frequently associated with soil P fractions. We interpret our findings as evidence of widespread P partitioning at the community scale, affecting a relatively small proportion of tree species in this moderately fertile forest. We predict that stronger evidence of partitioning will be found at sites with lower P availability.