Biology subjects

Baiser, B.

Publications and source records attributed to Baiser, B..

4 recordsLinked to original sources

bioRxiv2023

Plant-mediated effects of fire and fragmentation drive plant-pollinator interaction β-diversity in fire-dependent pine savannas

Interaction {beta}-diversity is an essential measure to understand and conserve species interactions and ecosystem functioning. Interaction {beta}-diversity explains the variation in species interactions across spatial and temporal gradients, resulting from species turnover or interaction rewiring. Each component of interaction {beta}-diversity has different ecological implications and practical consequences. While interaction {beta}-diversity due to species turnover is related to assembly processes and fragmentation, rewiring can support high biodiversity and confer resilience to ecological networks. Despite this, it is unclear whether both components respond to the same or different ecological drivers. Here, we assessed the ecological drivers of plant-pollinator interaction {beta}-diversity and its components across 24 sites in 9 Longleaf Pine (LLP) savannas in north and central Florida. We evaluated the effects of flowering plant composition and flower abundance, vegetation, fire regime, soil moisture, terrain characteristics, climate, spatial context, and geographic location. We used path analysis to evaluate the drivers of spatial interaction {beta}-diversity and its main components. We then used generalized linear mixed models to assess the temporal patterns of spatial {beta}-diversity among sites within preserves. We found that plant-pollinator networks in LLP savannas are highly variable across space and time, mainly due to species turnover and possibly in response to abiotic gradients and dispersal boundaries. Flower abundance and flowering plant composition, geographic location, fire seasonality, soil moisture, and landscape context were the main drivers of plant-pollinator {beta}-diversity, highlighting the role of fire management and habitat connectivity in preserving plant-pollinator networks.

ecology↗

bioRxiv2018

Homogenization of species composition and species association networks are decoupled

Ecological communities are comprised of both species and the biotic relationships among them. Biotic homogenization in species composition (i.e. increased site-to-site similarity) is recognized a common consequence of global change, but less is known about how species relationships change over space and time. Does homogenization of species composition lead to homogenization of species relationships or are the dynamics of species relationships decoupled from changes in species composition? To answer this question, we used long-term resurvey data to analyze changes in plant species association patterns between the 1950s and 2000s at 266 sites distributed among three community types in Wisconsin, USA. We used species associations (quantified via local co-occurrence patterns) as a proxy for species relationships. Species pairs that co-occur more/less than expected by chance have positive/negative associations. Shifts in species associations consistently exceeded the shifts observed in species composition. Less disturbed forests of northern Wisconsin have converged somewhat in species composition but not much in species associations. In contrast, forests in central Wisconsin succeeding from pine barrens to closed-canopy forests have strongly homogenized in both species composition and species associations. More fragmented forests in southern Wisconsin also tended to converge in species composition and in the species negative associations, but their positive associations diverged over the last half century. We conclude that long-term shifts in species relationships may be decoupled from those of species composition despite being affected by similar environmental variables.

ecology↗

bioRxiv2017

Ecological Network Metrics: Opportunities For Synthesis

Network ecology provides a systems basis for approaching ecological questions, such as factors that influence biological diversity, the role of particular species or particular traits in structuring ecosystems, and long-term ecological dynamics (e.g. stability). Whereas the introduction of network theory has enabled ecologists to quantify not only the degree, but also the architecture of ecological complexity, these advances have come at the cost of introducing new challenges, including new theoretical concepts and metrics, and increased data complexity and computational intensity. Synthesizing recent developments in the network ecology literature, we point to several potential solutions to these issues: integrating network metrics and their terminology across sub-disciplines; benchmarking new network algorithms and models to increase mechanistic understanding; and improving tools for sharing ecological network research, in particular \"model\" data provenance, to increase the reproducibility of network models and analyses. We propose that applying these solutions will aid in synthesizing ecological subdisciplines and allied fields by improving the accessibility of network methods and models.

ecology↗

bioRxiv2016

Regime shifts, alternative states and hysteresis in the Sarracenia microecosystem

Changes in environmental conditions can lead to rapid shifts in the state of an ecosystem (\"regime shifts\"), which, even after the environment has returned to previous conditions, subsequently recovers slowly to the previous state (\"hysteresis\"). Large spatial and temporal scales of dynamics, and the lack of frameworks linking observations to models, are challenges to understanding and predicting ecosystem responses to perturbations. The naturally-occurring microecosystem inside leaves of the northern pitcher plant (Sarracenia purpurea) exhibits oligotrophic and eutrophic states that can be induced by adding insect prey. Here, we further develop a model for simulating these dynamics, parameterize it using data from a prey addition experiment and conduct a sensitivity analysis to identify critical zones within the parameter space. Simulations illustrate that the microecosystem model displays regime shifts and hysteresis. Parallel results were observed in the plant itself after experimental enrichment with prey. Decomposition rate of prey was the main driver of system dynamics, including the time the system remains in an anoxic state and the rate of return to an oxygenated state. Biological oxygen demand in fluenced the shape of the systems return trajectory. The combination of simulated results, sensitivity analysis and use of empirical results to parameterize the model more precisely demonstrates that the Sarracenia microecosystem model displays behaviors qualitatively similar to models of larger ecological systems.

ecology↗