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opencc-zeroDec 2012View details →

Data from: Increasing zooplankton size diversity enhances the strength of top-down control on phytoplankton through diet niche partitioning

1. The biodiversity-ecosystem functioning debate is a central topic in ecology. Recently, there has been a growing interest in size diversity because body size is sensitive to environmental changes and is one of the fundamental characteristics of organisms linking many ecosystem properties. However, how size diversity affects ecosystem functioning is an important yet unclear issue. 2. To fill the gap, with large-scale field data from the East China Sea, we tested the novel hypothesis that increasing zooplankton size diversity enhances top-down control on phytoplankton (H1) and compared it with five conventional hypotheses explaining the top-down control: flatter zooplankton size spectrum enhances the strength of top-down control (H2); nutrient enrichment lessens the strength of top-down control (H3); increasing zooplankton taxonomic diversity enhances the strength of top-down control (H4); increasing fish predation decreases the strength of top-down control of zooplankton on phytoplankton through trophic cascade (H5); increasing temperature intensifies the strength of top-down control (H6). 3. The results of univariate analyses support the hypotheses based on zooplankton size diversity (H1), zooplankton size spectrum (H2), nutrient (H3), and zooplankton taxonomic diversity (H4), but not the hypotheses based on fish predation (H5) and temperature (H6). More in depth analyses indicate that zooplankton size diversity is the most important factor in determining the strength of top-down control on phytoplankton in the East China Sea. 4. Our results suggest a new potential mechanism, that increasing predator size diversity enhances the strength of top-down control on prey through diet niche partitioning. This mechanism can be explained by the optimal predator-prey body-mass ratio concept. Suppose each size group of zooplankton predators has its own optimal phytoplankton prey size, increasing size diversity of zooplankton would promote diet niche partitioning of predators and thus elevates the strength of top-down control.

opencc-by-4.0May 2019View details →

Trophic niche partitioning of seven skate species (Rajidae), in the Northern and Central Patagonia, Argentina-Raw data

Skate´s content stomach information and statistics information

opencc-zeroDec 2017View details →

Data from: Isotopic and dietary niches as indicators for resource partitioning in the gleaner bats M. bechsteinii, M. nattereri, and P. auritus

The n-dimensional ecological niche summarizes all living requirements of a species. According to the competition and niche theory, co-occurring species have to differ in at least one dimension to live in stable coexistence. Measuring the overall ecological niche within natural ecosystems is probably impossible but methods that describe several dimensions at once like the isotopic niche are good approximations. However, the impact of each factor contributing to the isotopic niche might be difficult to estimate. The dietary niche, as one part of the isotopic niche, can be examined with high resolution using molecular techniques. In this study we aimed to improve our understanding of species coexistence. We outlined the importance of the isotopic and dietary niches in the context of resource partitioning using the bat species M. bechsteinii, M. nattereri, and P. auritus of the gleaner guild as examples. The dietary and isotopic niches were estimated with stable isotope analysis and molecular fecal analysis. We tested (i) how distinct the occupied dietary niches of members of the same guild are and (ii) how similar the dietary and isotopic niches are to each other. While the inter-specific overlap was high for the dietary niche, no overlap could be observed for the isotopic niche. In general, the isotopic niche can describe a more complete picture of the ecological niche, while the dietary niche provides highly detailed information. The combination of both niches might advance our understanding of stable species coexistences.

opencc-zeroDec 2014View details →

Data from: DNA metabarcoding illuminates dietary niche partitioning by African large herbivores

Niche partitioning facilitates species coexistence in a world of limited resources, thereby enriching biodiversity. For decades, biologists have sought to understand how diverse assemblages of large mammalian herbivores (LMH) partition food resources. Several complementary mechanisms have been identified, including differential consumption of grasses versus nongrasses and spatiotemporal stratification in use of different parts of the same plant. However, the extent to which LMH partition food-plant species is largely unknown because comprehensive species-level identification is prohibitively difficult with traditional methods. We used DNA metabarcoding to quantify diet breadth, composition, and overlap for seven abundant LMH species (six wild, one domestic) in semiarid African savanna. These species ranged from almost-exclusive grazers to almost-exclusive browsers: Grass consumption inferred from mean sequence relative read abundance (RRA) ranged from >99% (plains zebra) to <1% (dik-dik). Grass RRA was highly correlated with isotopic estimates of % grass consumption, indicating that RRA conveys reliable quantitative information about consumption. Dietary overlap was greatest between species that were similar in body size and proportional grass consumption. Nonetheless, diet composition differed between all species—even pairs of grazers matched in size, digestive physiology, and location—and dietary similarity was sometimes greater across grazing and browsing guilds than within them. Such taxonomically fine-grained diet partitioning suggests that coarse trophic categorizations may generate misleading conclusions about competition and coexistence in LMH assemblages, and that LMH diversity may be more tightly linked to plant diversity than is currently recognized.

opencc-zeroDec 2017View details →

Data from: Assessing niche partitioning of co-occurring sibling bat species by DNA metabarcoding

Niche partitioning through foraging is a mechanism likely involved in facilitating the coexistence of ecologically similar and co-occurring animal species by separating their use of resources. Yet, this mechanism is not well understood in flying insectivorous animals. This is particularly true of bats, where many ecologically similar or cryptic species coexist. The detailed analysis of the foraging niche in sympatric, cryptic sibling species provides an excellent framework to disentangle the role of specific niche factors likely involved in facilitating coexistence. We used DNA metabarcoding to determine the prey species consumed by a population of sympatric sibling Rhinolophus euryale and R. mehelyi whose use of habitat in both sympatric and allopatric ranges has been well established through radio tracking. Although some subtle dietary differences exist in prey species composition, the diet of both bats greatly overlapped (Ojk = 0.83) due to the consumption of the same common and widespread moths. Those dietary differences we did detect might be related to divergences in prey availabilities among foraging habitats, which prior radio tracking on the same population showed are differentially used and selected when both species co-occur. This minor dietary segregation in sympatry may be the result of foraging on the same prey-types and could contribute to reduce potential competitive interactions (e.g. for prey, acoustic space). Our results highlight the need to evaluate the spatial niche dimension in mediating the co-occurrence of similar insectivorous bat species, a niche factor likely involved in processes of bat species coexistence.

opencc-zeroJun 2021View details →

Habitat alteration facilitates the dominance of invasive species through disrupting niche partitioning in floodplain wetlands

Aim: Exotic species invasion often leads to declines in local and regional biodiversity, particularly in freshwater ecosystems. This biodiversity loss is generally facilitated by human activities such as land cover change and hydrological alternation. Recent advances in stable isotope analysis (SIA) have been highlighted in many studies addressing fundamental issues in invasion ecology, especially in quantifying competition for resources between native and exotic species. However, how anthropogenic disturbance influences trophic relationships among invasive and native species remains poorly understood. Location: Middle-lower Yangtze River region, China Methods: To investigate the effects of human disturbance on interspecific trophic interactions, this study compared isotopic niche space and overlap of the introduced red swamp crayfish (Procambarus clarkii) and the native oriental river shrimp (Macrobrachium nipponense) and freshwater snail (Bellamya aeruginosa) in natural and modified wetlands. Results: Based on carbon and nitrogen SIA, we found ubiquitous niche shifts in macroinvertebrates with increased competition, which might lead to significant niche contraction in modified habitats at both community and population scales. Moreover, the isotopic niche width of the exotic crayfish was twice as larger as that of natives at both habitats, suggesting that the exotic P. clarkii had great competitive superiority over the native species. However, the effects of habitat modification on niche overlap were inconsistent. While the niche overlap between crayfish and shrimp was significantly higher in modified habitats than in natural open waters, niche overlap between crayfish and the snail was significantly reduced. Main conclusions: Collectively, our findings highlight that the competitive outcomes of interspecific trophic interactions can be dependent on the prey availability and diversity, which embraces both the classic optimal foraging theory and competition theory to understand how environmental change, such as habitat alternation, affects the biological invasion processes.

Figure 2 in Body size estimation and evolution in metriorhynchid crocodylomorphs: implications for species diversification and niche partitioning

Figure 2. Evolutionary relationships of metriorhynchid genera based on the new phylogenetic analysis presented herein. Geological ranges are based on the taxonomic compendium in Young et al. (2010). Labelled nodes represent clades: (1) Metriorhynchidae; (2) Metriorhynchinae; (3) Geosaurinae; and (4) Geosaurini.

Figure 5 in Body size estimation and evolution in metriorhynchid crocodylomorphs: implications for species diversification and niche partitioning

Figure 5. Ordination plot of femoral length against total body length in living and fossil crocodylomorphs. The taxa from Farlow et al. (2005) are in light grey, and their Alligator 95% prediction interval is shown by the two parallel oblique lines.

Figure 4 in Body size estimation and evolution in metriorhynchid crocodylomorphs: implications for species diversification and niche partitioning

Figure 4. Ordination plot of cranial length against total body length in living and fossil crocodylomorphs. Convex hulls surround the different clades of crocodylomorphs.

Figure 3 in Body size estimation and evolution in metriorhynchid crocodylomorphs: implications for species diversification and niche partitioning

Figure 3. Evolutionary relationships of metriorhynchid species with body size data. Phylogeny based on the new phylogenetic analysis presented herein. Labelled nodes represent clades: (1) Metriorhynchidae; (2) Metriorhynchinae; (3) Geosaurinae; and (4) Geosaurini.

opencc-zeroOct 2021View details →

Timing is everything: Acoustic niche partitioning in two tropical wet forest bird communities

When acoustic signals sent from individuals overlap in frequency and time, acoustic interference and signal masking may occur. Under the acoustic niche hypothesis (ANH), signaling behavior has evolved to partition acoustic space and minimize overlap with other calling individuals through selection on signal structure and/or the sender's ability to adjust the timing of signals. Alternately, under the acoustic clustering hypothesis, there is potential benefit to convergence and synchronization of the structural or temporal characteristics of signals in the avian community, and organisms produce signals that overlap more than would be expected by chance. Interactive communication networks may also occur, where species living together are more likely to have songs with convergent spectral and or temporal characteristics. In this study, we examine the fine-scale use of acoustic space in montane tropical wet forest bird communities in Costa Rica and Hawai'i. At multiple recording stations in each community, we identified the species associated with each recorded signal, measured observed signal overlap, and used null models to generate random distributions of expected signal overlap. We then compared observed vs. expected signal overlap to test predictions of the acoustic niche and acoustic clustering hypotheses. We found a high degree of overlap in the signal characteristics (frequency range) of species in both Costa Rica and Hawai'i, however, as predicted under ANH, species significantly reduced observed overlap relative to the random distribution through temporal partitioning. There was little support for acoustic clustering or the prediction of the network hypothesis that species segregate across the landscape based on the frequency range of their vocalizations. These findings constitute strong support that there is competition for acoustic space in these signaling communities, and this has resulted primarily in temporal partitioning of the soundscape.

opencc-by-4.0Dec 2022View details →

Multi-proxy dentition analyses reveal niche partitioning between sympatric herbivorous dinosaurs

In this link we uploaded the raw data related to the MS entitled "Multi-proxy dentition analyses reveal niche partitioning between sympatric herbivorous dinosaurs" submitted to Scientific Reports. These files are used for 3D modelling (volumetric calculation and OPCR tooth crown complexity), CT imaging and 2D and 3D microwear files.

opencc-zeroMar 2023View details →

Data for the article: Trophic niche partitioning between two prey and their incidental predators revealed various threats for an endangered species

Documenting trophic niche partitioning and resource use within a community is critical to evaluate underlying mechanisms of coexistence, competition or predation. Detailed knowledge about foraging is essential as it may influence the vital rates, which, in turn, can affect trophic relationships between species and population dynamics. The aims of this study were to evaluate resource and trophic niche partitioning in summer/autumn between the endangered Atlantic-Gaspésie caribou (Rangifer tarandus caribou) population, moose (Alces americanus) and their incidental predators, the black bear (Ursus americanus) and coyote (Canis latrans), and to quantify the extent to which these predators consumed caribou. Bayesian isotopic analysis showed a small overlap in trophic niche for the two sympatric ungulates suggesting a low potential for resource competition. Our result also revealed that caribou occupied a larger isotopic niche area than moose, suggesting a greater diversity of resources used by caribou. Not surprisingly, coyote consumed mainly deer (Odocoileus virginianus), moose, snowshoe hare (Lepus americanus), and occasionally caribou, while bears consumed mainly vegetation and, to a lesser extent, moose and caribou. As coyotes and bears also feed on plant species, we documented trophic niche overlap between caribou and their predators, as searching for similar resources can force them to use the same habitats and thus increase the encounter rate and, ultimately, mortality risk for caribou. Although the decline of the Gaspésie caribou population is mostly driven by habitat-mediated predation, we found evidence that the low level of resource competition with moose added to the shared resources with incidental predators, mainly bears, may contribute to jeopardize the recovery of this endangered caribou population. Highlighting the trophic interaction between species is needed to establish efficient conservation and management strategies to insure the persistence of endangered populations. The comparison of trophic niches of species sharing the same habitat or resources is fundamental to evaluate the mechanisms of coexistence or competition and eventually predict the consequences of ecosystem changes in the community.

opennotspecifiedJan 2023View details →

FIG. 1 in Habitat Usage, Dietary Niche Overlap, and Potential Partitioning between the Endangered Spotted Turtle (Clemmys guttata) and Other Turtle Species

FIG. 1. The path analysis shows the relationship between habitat parameters associated with PC1 (which was strongly positively loaded with salinity, depth, dissolved O2, canopy cover, and pH) and three turtle species: Chrysemys picta, Kinosternon subrubrum, and Clemmys guttata on the Atlantic Coastal Plain. The solid and dashed lines represent direct and indirect effects, respectively, and black lines indicate positive effects while gray lines indicate negative effects. The numbers associated with each line represent the direction and magnitude of each effect, with the strength of the interaction increasing as the values approach 1.

opennotspecifiedJan 2023View details →

FIG. 2 in Habitat Usage, Dietary Niche Overlap, and Potential Partitioning between the Endangered Spotted Turtle (Clemmys guttata) and Other Turtle Species

FIG. 2. Biplots of d15N and d13C for four turtle species at all sites with ellipses around each species (filled squares/solid black line ¼ Kinosternon subrubrum, filled triangles/solid gray line ¼ Chrysemys picta, open circles/gray dashed line¼ Chelydra serpentina, filled diamonds/ lack dashed line ¼ Clemmys guttata). There is a large overlap in isotopic compositions for all species, resulting in no significant differences in isotopic niche space between species (see text).

opennotspecifiedJan 2023View details →

FIG. 3 in Habitat Usage, Dietary Niche Overlap, and Potential Partitioning between the Endangered Spotted Turtle (Clemmys guttata) and Other Turtle Species

FIG. 3. Bivariate SIBER (Stable Isotope Bayesian Ellipses in R) plots of ellipses estimating isotopic niche based on the d13C and d15N compositions with all species, excluding C. serpentina. The black circles represent the mode, while the three ellipses from the center outwards show where 50%, 75%, and 95% of the data lie, respectively. The numbers indicate the site numbers, while the letter codes indicate species names (MUDT ¼ Kinosternon subrubrum, PATU ¼ Chrysemys picta, SPTU ¼ Clemmys guttata). Together, these bivariate data of the isotopic compositions create ellipses which represent the relative sizes of the isotopic niche of each turtle species at all of our sites on the Atlantic Coastal Plain. Despite the lack of any significant differences in isotopic niche, these ellipses allow us to see some degree of niche overlap among C. guttata at all sites.

FIGURE 9 in Two new Thereus species from Peru, with notes on ecological niche partitioning (Lepidoptera: Lycaenidae: Theclinae)

FIGURE 9. Type locality of Thereus tierralinda sp. nov., with the Manu Road going through Chontachaca on the North along the Cosñipata river (source: Google Earth).

FIGURES 15–19 in Two new Thereus species from Peru, with notes on ecological niche partitioning (Lepidoptera: Lycaenidae: Theclinae)

FIGURES 15–19. Male genitalia, ventral view (on right), left lateral view (at left). 15. Thereus tierralinda sp. nov. (HT, Peru, MUSM). 16. T. illex (Colombia, MNHN). 17. T. columbicola (Peru, CF). 18. T. eryssus (Brazil, CF). 19. T. vicens sp. nov. (HT, Peru, MUSM).

FIGURE 24 in Two new Thereus species from Peru, with notes on ecological niche partitioning (Lepidoptera: Lycaenidae: Theclinae)

FIGURE 24. Flight zone of T. tierralinda sp. nov. in 2019 and 2021 (higher oval) and the approximate flight zone of T. columbicola in 2017 and 2018 (lower oval) from a riverside clearing adjacent to the Tierra Linda Reserve camp (picture taken in 2021). Arrows indicate the preferred location for the observation posts.

FIGURES 20–22 in Two new Thereus species from Peru, with notes on ecological niche partitioning (Lepidoptera: Lycaenidae: Theclinae)

FIGURES 20–22. Female genitalia. Ventral view (at left), lateral view (middle), papilla analis in lateral view (at right). 20. Thereus columbicola (Peru, CF). 21. T. eryssus (Brazil, CF). 22. T. vicens sp. nov. (HT, Peru, MUSM).