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Biology subjects

Tylianakis, J. M.

Publications and source records attributed to Tylianakis, J. M..

12 recordsLinked to original sources

Effects of management on global crop pest damage depends on coevolutionary indicators

Pests and pathogens reduce yields of major food crops by 15% globally1. Interventions such as pesticides can mitigate yield loss, but pests can evolve resistance to pesticides over short timescales2,3. Pest damage to crops may also be determined by (co)evolutionary selection on pests by crops themselves and vice versa4, yet it is unclear whether the relative evolutionary potential of pests versus crops predicts the outcome of this arms race. Here we test whether readily available indicators of the evolutionary potential5-9 of crops and their pests or pathogens influence global yield loss10 and its response to agricultural management11-13. We find that evolutionary potential of the pest (measured as its genome size) and crop (measured as population density or proximity of wild relatives) moderated the effect of agricultural management (seed importation, fertiliser and pesticide use) on crop damage. Crucially, statistical interactions among crop and pest evolutionary potentials explained as much variation in yield loss as did agricultural management. Our results show a huge spatial variability in management effectiveness and suggest greatest benefit in places with a stronger imbalance in the evolutionary potential between crop and pest. More broadly, our findings reveal a key role of evolution in determining present-day pest damage.

evolutionary biology↗

Partner fidelity with root symbionts impacts plant performance in the face of changing above- and belowground community context

Global environmental changes generate novel communities. Some species adapt to novel community contexts by demonstrating interaction fidelity, or consistently interacting with the same species, while others demonstrate interaction flexibility, or interacting with whichever partners are available (i.e., rewiring). However, the drivers and benefits of fidelity are unclear. Here, we use data from a large-scale mesocosm experiment to determine whether plant characteristics (e.g., provenance, functional group) and community contexts impact plant interaction fidelity to belowground mutualist and antagonist partners (i.e., root fungi and bacteria), and how this fidelity relates to plant performance. We found that the plant-antagonist relationships exhibited higher fidelity than plant-mutualist relationships with the strength of fidelity depending on a combination of plant characteristics and community context. Conversely, plant-mutualist fidelity impacted plant performance with competing effects depending on plant provenance and aboveground herbivore presence. Our study advances understanding of how species interactions influence plant performance in a changing world. Statement of authorshipAMM, JDT, JMT and DBS designed the concept. All authors contributed to refining the ideas. AM coded the analysis to produce the results with contributions from JDT, DBS, and BBM. HRL and DBS helped AMM with the statistical analysis. LPW, WJA, IAD, and JMT designed the experiment while LPW and WJA conducted the experiment. AMM wrote the first draft of the manuscript with assistance from all authors. IAD, JMT, and JDT obtained funding. All authors contributed to further editing of the manuscript.

ecology↗

Mobile species' responses to surrounding land use generate trade-offs among nature's contributions to people

Agricultural landscapes provide material, non-material and regulating contributions that affect human wellbeing. The responses of these natures contributions to people (NCP) to land-use patterns depend on supporting biota with different habitat requirements, generating trade-offs and synergies. Predictions of NCP trade-offs could inform land-use decisions, but these do not typically account for the effects of land-use patterns on the movement of NCP-providing species, nor for interactions among NCP providers. To explore spatial trade-offs and synergies in eight indicators of NCP, we used Bayesian models that allow for interactions among land uses and among NCP using data from 150 grassland sites across rural Germany. We found that spatial arrangements of forest and open habitat influenced many NCP: acoustic diversity, birdwatching potential, natural enemy abundance and pollination. In particular, the amount and proximity of land uses in the surrounding landscape, especially forest and open habitat, drove the supply of most NCP. However, NCP provided by smaller-bodied taxa (herbivory and pathogen infection) responded weakly to landscape factors. Multiple NCP provided by a given taxon responded differently to their surrounding landscape (e.g. bird-provided caterpillar predation and seed predation), leading to trade-offs among NCP over short distances ([≤]60 m). These were caused by different rates and directions of response to amount and location of land uses. Resulting spatial predictions revealed that grassland-dominated or mixed forest-grassland areas better maximize beneficial NCP and minimize detrimental NCP across landscapes than purely forest-dominated areas. This suggests promoting semi-natural vegetation in agricultural landscapes to provide greater-than-additive benefits to net NCP supply. Significance StatementLand use affects natures contributions to people (NCP), including those provided by mobile species, in complex ways. Variation in the responses of species to the amount and location of land uses results in NCP trade-offs across landscapes, but decision-makers lack the capacity to spatially predict these trade-offs. We predict how the supply of both beneficial and detrimental NCP and associated trade-offs vary across diverse rural landscapes and find that grassland-dominated or mixed forest-grassland areas deliver higher net NCP supply than forest-dominated areas in our study system. Our findings support policies for promoting semi-natural vegetation cover in agricultural landscapes, as these may provide non-additive benefits for NCP.

ecology↗

Phenological turnover matters when making trait-based predictions of plant-pollinator interactions

1. Understanding the processes determining species interactions is key to predicting and safeguarding ecological networks under rapid environmental change. One approach to estimating interactions is to use morphologies of taxa interacting across trophic levels to reveal suites of traits they are more likely to interact with (i.e. a trait niche). 2. Previous work studying these morphological trait niches has typically used interactions between species that are pooled in space and time. However, species assemblages, and the traits of individuals within species, can change across even small landscapes over a season, leading to morphological trait space being dynamically reshaped. Therefore, it is unclear how morphological trait turnover affects our inferences of trait niches, and our ability to answer this is in part limited by a lack of individual-level trait data. 3. Here, we directly address this by studying a montane Arctic plant-pollinator community over five growing seasons (>1,300 hours of fieldwork). Specifically, we linked every recorded plant-bumblebee interaction with the traits of the bee individual involved (n = 1,150), to investigate 1) whether plant taxa (n = 10) exhibited bee trait niches by interacting with specific regions of multidimensional trait space of visiting bumblebees, and 2) how our inference of these trait niches was affected by considering bumblebee trait turnover and plant taxon turnover. 4. When not considering turnover (interactions in space and time are pooled), plant taxa demonstrated bee trait niches. However, next we considered how bee trait space is reshaped over the elevational and seasonal gradient (especially with the emergence of different castes), and how this reshaping co-occurs with different spatiotemporal ranges of the plant taxa. From this we found the degree to which plant taxa exhibited trait niches declined significantly, and that seasonal reshaping of bee trait space was the primary driver of this trend. 5. Overall, in highly dynamic systems, like the Arctic, overlooking community turnover could mask and even overestimate the ability of morphology to explain interactions. Hence, determining how morphological traits of individual interaction partners are in phenological synchrony at localised scales will be fundamental to understanding the role morphology plays in underpinning plant-pollinator interactions.

ecology↗

Plant interaction traits determine the biomass of arbuscular mycorrhizal fungi and bacteria in soil

Plant-arbuscular mycorrhizal fungal (AMF) mutualisms play key roles in the biodiversity and productivity of ecosystems. Yet we have limited understanding of the functional roles of plants as AMF generalists or specialists, and the consequences of these plant interaction traits for soil ecosystems are virtually unknown. We grew eight pasture plant species under two experimental conditions and determined their root AMF communities by sequencing. We determined plant species interaction traits with AMF using a set of numeric and phylogenetic -, {beta}- and {gamma}-diversities and characterized plant species relative interaction generalism for AMF. We used lipid analysis of rhizosphere soils and Bayesian modelling to explore how host interaction traits affected carbon allocation to AMF and bacteria. Plant interaction traits for AMF appear to be stable despite large variation in edaphic conditions and AMF pools. We show that host interaction generalism was associated with opposite patterns of bacterial and AMF biomass; the phylogenetic diversity of host interactions was positively associated with AMF biomass whereas the richness of host interactions was negatively associated with bacterial biomass in rhizosphere soils. Explicit consideration of plant interaction niches may enhance understanding of how changes in biodiversity affect ecosystem carbon cycling. Open research statementThis publication does not use novel code, and the bioinformatic and statistic pipelines for this manuscript will be made available at https://github.com/NLewe/Bayes-interaction-niche. Raw data will be made available at NCBI as BioProject: PRJNA997080

ecology↗

Species traits and community structure can drive large-scale spatial propagation of effects in ecosystems

Species can directly and indirectly affect others across communities and habitats, yet the spatial scale over which such effects spread remains unclear. This uncertainty arises partly because the species traits and landscape structures allowing indirect effects to propagate may differ across scales. Here, we use a topological network metric, communicability, to explore the spatial propagation of effects in a large-scale plant-frugivore network projected across the territory of Aotearoa New Zealand. We show that generalism and species prevalence, and complementary morphological traits such as fruit and body size, are important predictors of species capacity to propagate effects, but their importance differed across scales. Further-more, native bird species (but not exotics) showed a positive relationship between body size and their potential to propagate effects. Habitat composition was the most important land-scape factor in our study, generating hotspots of effect propagation around forested areas, whereas landscapes containing a variety of habitats acted as a buffer against propagation. Overall, our results indicate that species displaying specific sets of traits, including ubiquity, interaction generalism, and a combination of large body size and native status, are the most likely to propagate large-scale ecological impacts in the plant-frugivore communities studied, yet landscape properties may moderate this spread.

ecology↗

Mapping trait versus species turnover reveals spatiotemporal variation in functional redundancy in a plant-pollinator network

Functional overlap between species (redundancy) shapes competitive and mutualistic interactions, determining community responses to perturbations. Most studies view functional redundancy as static, even though individuals within species vary in traits over seasonal or spatial gradients. Consequently, we lack knowledge on trait turnover within species, how functional redundancy spatiotemporally varies, and when and where interaction networks are vulnerable to functional loss. Studying an Arctic bumblebee community, we investigated how body-size turnover over elevation and season shapes their host-plant interactions, and test how sensitive networks are to sequentially losing body-size groups. With trait turnover being larger than species, we found: i) late-season networks were less specialised when nodes comprised functionally similar bumblebees; ii) removal of bumblebee-body-size groups over species accelerated coextinction of host plants, with the magnitude varying in space and time. We demonstrate functional redundancy can vary spatiotemporally, and functional loss impacts interaction partners more than expected from species loss alone.

ecology↗

Less is worse than none: ineffective adaptive foraging can destabilise food webs

O_LIConsumers can potentially adjust their diet in response to changing resource abundances, thereby achieving better foraging payoffs. Although previous work has explored how such adaptive foraging scales up to determine the structure and dynamics of food webs, consumers may not be able to perform perfect diet adjustment due to sensory or cognitive limitations. Whether the effectiveness of consumers diet adjustment alters food-web consequences remains unclear. C_LIO_LIHere, we study how adaptive foraging, specifically the effectiveness (i.e. rate) with which consumers adjust their diet, influences the structure, dynamics, and overall species persistence in synthetic food webs. C_LIO_LIWe model metabolically-constrained optimal foraging as the mechanistic basis of adaptive diet adjustment and ensuing population dynamics within food webs. We compare food-web dynamical outcomes among simulations sharing initial states but differing in the effectiveness of diet adjustment. C_LIO_LIWe show that adaptive diet adjustment generally makes food-web structure resilient to species loss. Effective diet adjustment that maintains optimal foraging in the face of changing resource abundances facilitates species persistence in the community, particularly reducing the extinction of top consumers. However, a greater proportion of intermediate consumers goes extinct as optimal foraging becomes less-effective and, unexpectedly, slow diet adjustment leads to higher extinction rates than no diet adjustment at all. Therefore, food-web responses cannot be predicted from species responses in isolation, as even less-effective adaptive foraging benefits individual species (better than non-adaptive) but can harm species persistence in the food web as a whole (worse than non-adaptive). C_LIO_LIWhether adaptive foraging helps or harms species coexistence has been contradictory in literature Our finding that it can stabilise or destabilise the food web depending on how effectively it is performed help reconcile this conflict. Inspired by our simulations, we deduce that there may exist a positive association between consumers body size and adaptive-foraging effectiveness in the real world. We also infer that such effectiveness may be higher when consumers cognise complete information about their resources, or when trophic interactions are driven more by general traits than by specific trait-matching. We thereby suggest testable hypotheses on species persistence and food-web structure for future research, in both theoretical and empirical systems. C_LI

ecology↗

Global and regional ecological boundaries drive abrupt changes in avian frugivory interactions

Species interactions can propagate disturbances across space, though ecological and biogeographic boundaries may limit this spread. We tested whether large-scale ecological boundaries (ecoregions and biomes) and human disturbance gradients increase dissimilarity among ecological networks, while accounting for background spatial and elevational effects and differences in network sampling. We assessed network dissimilarity patterns over a broad spatial scale, using 196 quantitative avian frugivory networks (encompassing 1,496 plant and 1,003 bird species) distributed across 67 ecoregions and 11 biomes. Dissimilarity in species and interactions, but not in network structure, increased significantly across ecoregion and biome boundaries and along human disturbance gradients. Our findings suggest that ecological boundaries contribute to maintaining the worlds biodiversity of interactions and mitigating the propagation of disturbances at large spatial scales. One-Sentence SummaryEcoregions and biomes delineate the large-scale distribution of plant-frugivore interactions.

ecology↗

Environment affects specialisation of plants and pollinators

What determines whether or not a species is a generalist or a specialist? Evidence that the environment can influence species interactions is rapidly accumulating. However, a systematic link between environment and the number of partners a species interacts with has been elusive so far. Presumably, because environmental gradients appear to have contrasting effects on species depending on the environmental variable. Here, we test for a relationship between the stresses imposed by the environment, instead of environmental gradients directly, and species specialisation using a global dataset of plant-pollinator interactions. We found that the environment can play a significant effect on specialisation, even when accounting for community composition, likely by interacting with species traits and evolutionary history. Species that have a large number of interactions are more likely to focus on a smaller number of, presumably higher-quality, interactions under stressful environmental conditions. Contrastingly, the specialists present in multiple locations are more likely to broaden their niche, presumably engaging in opportunistic interactions to cope with increased environmental stress. Indeed, many apparent specialists effectively behave as facultative generalists. Overall, many of the species we analysed are not inherently generalist or specialist. Instead, species level of specialisation should be considered on a relative scale depending on where they are found and the environmental conditions at that location.

ecology↗

The trade-offs of sharing pollinators: pollination service is determined by the community context

A fundamental feature of pollination systems is the indirect facilitation and competition that arises when plants species share pollinators. When plants share pollinators, the pollination service can be influenced. This depends not only on how many partners plant species share, but also by multiple intertwined factors like the plant species abundance, visitation, or traits. These factors inherently operate at the community level. However, most of our understanding of how these factors may affect the pollination service is based on systems of up to a handful of species. By examining comprehensive empirical data in eleven natural communities, we show here that the pollination service is--surprisingly--only partially influenced by the number of shared pollinators. Instead, the factors that most influence the pollination service (abundance and visit effectiveness) also introduce a trade-off between the absolute amount of conspecific pollen received and the amount relative to heterospecific pollen. Importantly, the ways plants appear to balance these trade-offs depend strongly on the community context, as most species showed flexibility in the strategy they used to cope with competition for pollination.

ecology↗

Meta-analysis reveals that the provision of multiple ecosystem services requires a diversity of land covers

Sustaining multiple ecosystem services across a landscape requires an understanding of how consistently services are shaped by different categories of land uses. Yet, this understanding is generally constrained by the availability of fine-resolution data for multiple services across large areas and the spatial variability of land-use effects on services. We systematically surveyed published literature for New Zealand (1970 - 2015) to quantify the supply of 17 services across 25 land covers (as a proxy for land use). We found a consistent trade-off in the services supplied by anthropogenic land covers with a high production intensity (e.g., cropping) versus those with extensive or no production. In contrast, forest cover was not associated with any distinct patterns of service supply. By drawing on existing research findings we reveal complementarity and redundancy (potentially influencing resilience) in service supply from different land covers. This can guide practitioners in shaping land systems that sustainably support human well-being.

ecology↗