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opencc-zeroDec 2015View details →

Data from: Translocation strategies for multiple species depend on interspecific interaction type

Conservation translocations – anthropogenic movements of species to prevent their extinction – have increased substantially over the last few decades. Although multiple species are frequently moved to the same location, current translocation guidelines consider species in isolation. This practice ignores important interspecific interactions, and thereby risks translocation failure. We model three different two-species systems to illustrate the inherent complexity of multi-species translocations, and to assess the influence of different interaction types (consumer-resource, mutualism, and competition) on translocation strategies. We focus on how these different interaction types influence the optimal founder population sizes for successful translocations, and the order in which the species are moved (simultaneous or sequential). Further, we assess the effect of interaction strength in simultaneous translocations, and the time delay between translocations when moving two species sequentially. Our results show that translocation decisions need to reflect the type of interaction. While all translocations of interacting species require a minimum founder population size, which is demarked by an "extinction boundary", consumer-resource translocations also have a maximum founder population limit. Above the minimum founder size, increasing the number of translocated individuals leads to a substantial increase in the extinction boundary of competitors and consumers, but not of mutualists. Competitive and consumer-resource systems benefit from sequential translocations; but the order of translocations does not change the outcomes for mutualistic interaction partners noticeably. Interspecific interactions are important processes that shape population dynamics, and should therefore be incorporated into the quantitative planning of multispecies translocations. Our findings apply whenever interacting species are moved, for example, in reintroductions, conservation introductions, biological control or ecosystem restoration.

opencc-zeroDec 2017View details →

Data from: Introduced ants reduce interaction diversity in a multi-species, ant-aphid mutualism

Mutualisms contribute in fundamental ways to the origin, maintenance and organization of biological diversity. Introduced species commonly participate in mutualisms, but how this phenomenon affects patterns of interactions among native mutualists remains incompletely understood. Here we examine how networks of interactions among aphid-tending ants, ant-tended aphids, and aphid-attacking parasitoid wasps differ between 12 spatially paired riparian study sites with and without the introduced Argentine ant Linepithema humile in southern California. To resolve challenges in species identification, we used DNA barcoding to identify aphids and screen for parasitoid wasps (developing inside their aphid hosts) from 170 aphid aggregations sampled on arroyo willow Salix lasiolepis. Compared to uninvaded sites, invaded sites supported significantly fewer species of aphid-tending ants and ant-tended aphids. At invaded sites, for example, we found only two species of ant-tended aphids, which were exclusively tended by L. humile, whereas at uninvaded sites we found 20 unique ant–aphid interactions involving eight species of ant-tended aphids and nine species of aphid-tending ants. Ant–aphid linkage density was thus significantly lower at invaded sites compared to uninvaded sites. We detected aphid parasitoids in 14% (28/198) of all aphid aggregations. Although the level of parasitism did not differ between invaded and uninvaded sites, more species of wasps were detected within uninvaded sites compared to invaded sites. These results provide a striking example of how the assimilation of introduced species into multi-species mutualisms can reduce interaction diversity with potential consequences for species persistence.

Data from: Species richness and interacting factors control invasibility of a marine community

Anthropogenic vectors have moved marine species around the world leading to increased invasions and expanded species' ranges. The biotic resistance hypothesis of Elton (in The ecology of invasions by animals and plants, 1958) predicts that more diverse communities should have greater resistance to invasions, but experiments have been equivocal. We hypothesized that species richness interacts with other factors to determine experimental outcomes. We manipulated species richness, species composition (native and introduced) and availability of bare space in invertebrate assemblages in a marina in Monterey, CA. Increased species richness significantly interacted with both initial cover of native species and of all organisms to collectively decrease recruitment. Although native species decreased recruitment, introduced species had a similar effect, and we concluded that biotic resistance is conferred by total species richness. We suggest that contradictory conclusions in previous studies about the role of diversity in regulating invasions reflect uncontrolled variables in those experiments that modified the effect of species richness. Our results suggest that patches of low diversity and abundance may facilitate invasions, and that such patches, once colonized by non-indigenous species, can resist both native and non-indigenous species recruitment.

opencc-zeroDec 2016View details →

Data from: Using traits to assess nontransitivity of interactions among coral species

Simulations and experiments have shown that species coexistence can be maintained via nontransitive competition, of which a simple case is the rock-paper-scissors game. Reef-building corals exemplify high biodiversity competing for a few limiting resources via several mechanisms. Thus, corals represent fertile ground for exploring competition and nontransitivity. This article aimed to test hypotheses about the effects of species-level traits on competitive outcomes, specifically, that more upright growth, larger corallites, smaller ranges, and difference in commonness co-occur with competitive superiority. Further aims were to test whether closely related species show less predictable competitive outcomes and greater nontransitivity and to examine the level of nontransitivity among a large number of species. These goals were addressed by fitting a mixed-effects model to outcomes of 2,322 interspecific interactions. Among species-level traits, corallite width had the greatest impact on outcome, followed by geographical range size, growth form, and the typical commonness of conspecifics in assemblages. These fixed effects had smaller estimated impacts than a random effect associated with species pair, suggesting a primary role for idiosyncratic species-pair or other factors. Closely related species had more variable, less predictable interaction outcomes. Nearly a quarter of three-way species relations were nontransitive. The observed degree of competitive nontransitivity and extent of idiosyncratic species-pair effects together provide an empirical baseline for further investigations of mechanisms of species coexistence.

Data from: Inferring species interactions in ecological communities: a comparison of methods at different levels of complexity

1. Natural communities commonly contain many different species and functional groups, and multiple types of species interactions act simultaneously, such as competition, predation, commensalism or mutualism. However, experimental and theoretical investigations have generally been limited by focusing on one type of interaction at a time or by a lack of a common methodological and conceptual approach to measure species interactions. 2. We compared four methods to measure and express species interactions. These approaches are, with increasing degree of model complexity, an extinction-based model, a relative yield model and two generalized Lotka-Volterra (LV) models. All four approaches have been individually applied in different fields of community ecology, but rarely integrated. We provide an overview of the definitions, assumptions and data needed for the specific methods and apply them to empirical data by experimentally deriving the interaction matrices among 11 protist and rotifer species, belonging to three functional groups. Furthermore, we compare their advantages and limitations to predict multispecies community dynamics and ecosystem functioning. 3. The relative yield method is, in terms of final biomass production, the best method in predicting the 11-species community dynamics from the pairwise competition experiments. The LV model, which is considering equilibrium among the species, suffers from experimental constraints given the strict equilibrium assumption, and this may be rarely satisfied in ecological communities. 4. We show how simulations of a LV stochastic community model, derived from an empirical interaction matrix, can be used to predict multispecies community dynamics across multiple functional groups. 5. Our work unites available tools to measure species interactions under one framework. This improves our ability to make management-oriented predictions of species coexistence/extinction and to compare ecosystem processes across study systems.

Data from: Process-based species pools reveal the hidden signature of biotic interactions amid the influence of temperature filtering

A persistent challenge in ecology is to tease apart the influence of multiple processes acting simultaneously and interacting in complex ways to shape the structure of species assemblages. We implement a heuristic approach that relies on explicitly defining species pools and permits assessment of the relative influence of the main processes thought to shape assemblage structure: environmental filtering, dispersal limitations and biotic interactions. We illustrate our approach using data on the assemblage composition and geographic distribution of hummingbirds, a comprehensive phylogeny and morphological traits. The implementation of several process-based species pool definitions in null models suggests that temperature, but not precipitation or dispersal limitation, acts as the main regional filter of assemblage structure. Incorporating this environmental filter directly into the definition of assemblage-specific species pools revealed an otherwise hidden pattern of phylogenetic evenness, indicating that biotic interactions might further influence hummingbird assemblage structure. Such hidden patterns of assemblage structure call for a reexamination of a multitude of phylogenetic- and trait-based studies that did not explicitly consider potentially important processes in their definition of the species pool. Our heuristic approach provides a transparent way to explore patterns and refine interpretations of the underlying causes of assemblage structure.

opencc-zeroDec 2013View details →

Data from: Linking phenological shifts to species interactions through size-mediated priority effects

1. Inter-annual variation in seasonal weather patterns causes shifts in the relative timing of phenological events of species within communities, but we currently lack a mechanistic understanding of how these phenological shifts affect species interactions. Identifying these mechanisms is critical to predicting how inter-annual variation affects populations and communities. 2. Species' phenologies, particularly the timing of offspring arrival, play an important role in the annual cycles of community assembly. We hypothesize that shifts in relative arrival of offspring can alter interspecific interactions through a mechanism called size-mediated priority effects (SMPE), in which individuals that arrive earlier can grow to achieve a body size advantage over those that arrive later. 3. In this study, we used an experimental approach to isolate and quantify the importance of SMPE for species interactions. Specifically, we simulated shifts in relative arrival of the nymphs of two dragonfly species to determine the consequences for their interactions as intraguild predators. 4. We found that shifts in relative arrival altered not only predation strength but also the nature of predator-prey interactions. When arrival differences were great, SMPE allowed the early arriver to prey intensely upon the late arriver, causing exclusion of the late arriver from nearly all habitats. As arrival differences decreased, the early arriver's size advantage also decreased. When arrival differences were smallest, there was mutual predation, and the two species coexisted in similar abundances across habitats. Importantly, we also found a nonlinear scaling relationship between shifts in relative arrival and predation strength. Specifically, small shifts in relative arrival caused large changes in predation strength while subsequent changes had relatively minor effects. 5. These results demonstrate that SMPE can alter not only the outcome of interactions but also the demographic rates of species and the structure of communities. Elucidating the mechanisms that link phenological shifts to species interactions is crucial for understanding the dynamics of seasonal communities as well as for predicting the effects of climate change on these communities.

opencc-zeroDec 2017View details →

Data from: A multi-state dynamic occupancy model to estimate local colonization-extinction rates and patterns of co-occurrence between two or more interacting species

1. Although ecology is rife with theory that explores how multiple species co-occur through space and time, the field lacks robust statistical models to parameterize this theory with empirical data, particularly when species are detected imperfectly and data are collected as a time-series. 2. We address this need by developing an occupancy model that estimates local colonization and extinction rates for two or more interacting species when data are collected across multiple sampling occasions. This model estimates how community composition at a site may change across sampling occasions by assuming the latent occupancy state is a categorical random variable. We used a multinomial-logit model to parameterize species-specific parameters and pairwise interactions between species, both of which can be made a function of covariates. These transition probabilities between community states can then be converted to occupancy or co-occurrence probabilities to determine how community composition varies along an environmental gradient or through time. 3. As an example, we estimate patterns of co-occurrence between coyote (Canis latrans), Virginia opossum (Didelphis virginiana), and raccoon (Procyon lotor) in Chicago, Illinois, USA with data from a multi-year camera trapping study. Models with pairwise interactions between species greatly out performed models that assumed independence between species. Opossum and raccoon, for example, were far less likely to go extinct in habitat patches where coyotes were present. 4. Community composition at a site depends on species interactions and the local environment. Our model can separate such effects by estimating the underlying processes that define species occurrence patterns. As a result, our model can more explicitly quantify a wide range of ecological dynamics and therefore be used to empirically test ecological theory, such as estimating priority effects at a site or turnover rates between species, both of which can be made to vary as a function of covariates.

Data from: Species-specific plant-soil feedback effects on above-ground plant-insect interactions

1. Plant–soil feedback (PSF) effects on plant performance strongly depend on the plant species that conditioned the soil. Recent studies have shown that PSF can change above-ground plant–insect interactions via soil-mediated changes in plant quality, but whether these effects depend on species-specific soil conditioning is unknown. We examined how PSF effects of several plant species influence above-ground plant–aphid interactions. 2. We grew ragwort (Jacobaea vulgaris) in field soil conditioned specifically by 10 plant species, belonging to three functional groups (grasses, forbs and legumes), in a multispecies mixture of the conditioned soils and in control (unconditioned) field soil. We measured plant biomass, concentrations of primary (amino acids) and secondary (pyrrolizidine alkaloids) metabolites in phloem exudates, and performance of the generalist aphid Brachycaudus cardui and the specialist Aphis jacobaeae. 3. We observed that plant species, via species-specific effects on soil fungal communities, exerted unique plant–soil effects on J. vulgaris biomass, amino acid concentrations in phloem exudates and aphid performance. The direction and magnitude of the species-specific PSF effects on aphid performance differed between both aphid species. PSF effects on soil fungal communities, plant biomass and A. jacobaeae performance also differed between grasses, forbs and legumes, with soil conditioning by forbs resulting in lowest plant biomass and aphid performance. 4. Synthesis. Our study provides novel evidence that PSF effects on above-ground plant–insect interactions are highly species specific. Our results add a new dimension to the rapidly developing research fields of PSF and above-below-ground interactions, and highlights that these fields are tightly linked.

FIGURE 8 in Description and host interactions of a new species of Exetasis Walker (Diptera: Acroceridae), with a key to species of the genus

FIGURE 8. Exetasis jujuyensis Gillung sp. nov. pupa. A. dorsal view; B. lateral view.

FIGURE 5 in Description and host interactions of a new species of Exetasis Walker (Diptera: Acroceridae), with a key to species of the genus

FIGURE 5. Acanthoscurria sternalis, dead spider showing the parasitoid's emergence opening.

FIGURE 4 in Description and host interactions of a new species of Exetasis Walker (Diptera: Acroceridae), with a key to species of the genus

FIGURE 4. Acanthoscurria sternalis, size of parasitoid's emergence opening.

FIGURE 3 in Description and host interactions of a new species of Exetasis Walker (Diptera: Acroceridae), with a key to species of the genus

FIGURE 3. Exetasis jujuyensis Gillung sp. nov. A. lateral view; B. dorsal view.

FIGURE 6 in Description and host interactions of a new species of Exetasis Walker (Diptera: Acroceridae), with a key to species of the genus

FIGURE 6. Exetasis jujuyensis Gillung sp. nov. larva attached to the spider tree trunk shelter.

FIGURE 1 in Description and host interactions of a new species of Exetasis Walker (Diptera: Acroceridae), with a key to species of the genus

FIGURE 1. Acanthoscurria sternalis, male, dorsal view.

opencc-by-4.0Nov 2023View details →

Raw data associated to the paper "Analysis of species pair associations combined with functional traits reveals the effects of environmental filtering and biotic interactions in an unmanaged temperate forest"

Open the record for dataset details and reuse information.

opencc-by-4.0Jun 2023View details →

Data accompanying "Oxidative stress changes interactions between two bacterial species from competitive to facilitative"

Raw data used to generate all figures in the associated manuscript.

opencc-by-4.0Mar 2024View details →

Pharsalus repandus (Hemiptera: Ricaniidae) with mutualistic interaction with two species of Camponotus

The ants who were attending the planthoppers was identified as Camponotus rufipes (Fabricius, 1775) and Camponotus crassus Mayr, 1862 (Fig. 2A, D, arrow 2). We noted direct contact and observed the ants employing antennal palpation behavior to stimulate the planthoppers. The ant positions itself just behind the planthopper, delicately and repeatedly touching its wings with the tips of its antennae. In response to this interaction, the planthopper gradually elevates its forewings, although they do not fully open, and the anal margins remain unseparated. Concurrently, a droplet of honeydew is released. Additionally, we observed the planthoppers reacting to the presence of ants walking nearby with an extremely rapid movement of the wings, even though there was no physical contact between them.

opencc-zeroOct 2021View details →

Data from: Spatial variation in bidirectional pollinator-mediated interactions between two co-flowering species in serpentine plant communities

Pollinator-mediated competition and facilitation are two important mechanisms mediating co-flowering community assembly. Experimental studies, however, have mostly focused on evaluating outcomes for a single interacting partner at a single location. Studies that evaluate spatial variation in the bidirectional effects between co-flowering species are necessary if we aim to advance our understanding of the processes that mediate species coexistence in diverse co-flowering communities. Here, we examine geographic variation (i.e., at landscape level) in bidirectional pollinator-mediated effects between co-flowering Mimulus guttatus and Delphinium uliginosum. We evaluated effects on pollen transfer dynamics (conspecific and heterospecific pollen deposition) and plant reproductive success. We found evidence of asymmetrical effects (one species is disrupted and the other one is facilitated) but the effects were highly dependent on geographical location. Furthermore, effects on pollen transfer dynamics did not always translate to effects on overall plant reproductive success (i.e., pollen tube growth) highlighting the importance of evaluating effects at multiple stages of the pollination process. Overall, our results provide evidence of a spatial mosaic of pollinator-mediated interactions between co-flowering species and suggest that community assembly processes could result from competition and facilitation acting simultaneously. Our study highlights the importance of experimental studies that evaluate the prevalence of competitive and facilitative interactions in the field, and that expand across a wide geographical context, in order to more fully understand the mechanisms that shape plant communities in nature.