Biology subjects

Melian, C.

Publications and source records attributed to Melian, C..

4 recordsLinked to original sources

bioRxiv2026

Unexpected global biodiversity responses to climate change arise from complex adaptation, seascape, and dispersal dynamics

Global marine biodiversity peaks in the tropics and is widely projected to shift polewards under climate warming as species track thermal optima. These projections rely largely on phenomenological models that treat species responses as shifts in climate suitability and neglect fundamental eco-evolutionary dynamics. The consequences of these dynamics in fluctuating populations for global biodiversity patterns therefore remain unresolved. We addressed this deficit by integrating local adaptation, dispersal, and gene flow - mediated trait homogenisation into spatially explicit global simulations of >1,400 tropical reef fishes under climate change. Biodiversity responses departed systematically from simple poleward redistribution. Depending on the interaction between dispersal and adaptive capacity, latitudinal richness peaks widened or narrowed, shifted equatorward or poleward, or collapsed entirely. These alternative regimes emerged from threshold-dependent interactions between seascape connectivity, metapopulation trait homogenisation, and accumulating thermal stress. Critically, greater dispersal enhanced persistence only below seascape-driven connectivity thresholds; beyond which homogenisation of traits across thermally heterogeneous populations disrupted local adaptation - particularly at metapopulation peripheries - and increased extinction risk. Continuous demographic feedback further generated cumulative stress and extinction tipping dynamics absent from snapshot suitability models. Our results show that eco-evolutionary dynamics can invert or destabilise expected climate-driven redistribution patterns, indicating that projections excluding these mechanisms may systematically misestimate the magnitude and direction of global biodiversity change in a rapidly warming ocean.

ecology↗

bioRxiv2024

Ecological diversification in sexual and asexual lineages

The presence or absence of sex can have a strong influence on the processes whereby species arise. Yet, the mechanistic underpinnings of this influence are poorly understood. To gain insights into the mechanisms whereby the reproductive mode may influence diversification, we investigate how natural selection, genetic mixing and the reproductive mode interact and how this interaction affects the evolutionary dynamics of diversifying lineages. To do so, we formulate and analyze trait-based eco-evolutionary models of ecological diversification for sexual and asexual lineages, in which diversification is driven by intraspecific resource competition. We find that the reproductive mode strongly influences the diversification rate and thus the ensuing diversity of a lineage. Our results reveal that natural selection is stronger in asexual lineages because asexual organisms have a higher reproductive potential than sexual ones. As a consequence, an asexual population can reach a higher population density than a sexual population under the very same ecological conditions. This causes competition, and thus ecologically-based selection, to be stronger in asexual lineages, promoting faster diversification. However, a small amount of genetic mixing accelerates the trait expansion process in sexual lineages, overturning the effect of selection alone and enabling a faster niche occupancy than asexual lineages. As a consequence, sexual lineages can occupy more ecological niches, eventually resulting in higher diversity. This suggests that sexual reproduction may be widespread among species because it increases rates of diversification.

evolutionary biology↗

bioRxiv2023

The architecture of multifunctional ecological networks

Understanding how biotic interactions affect ecosystem functioning has been a research priority in natural sciences due to their critical role in bolstering ecological resilience1-3. Yet, traditional assessment of ecological complexity typically focus on species-species effective interactions that mediate a particular function (e.g. pollination4 or seed dispersal5), overlooking the synergistic effect of multiple functions that further underpin species-function and function-function interactions in multifunctional ecosystems. At the same time, while ecological network theory holds a potential to quantify the relationship between biodiversity and ecosystem multifunctionality6, 7, its connection has been done mainly conceptually, due to challenges measuring different interactions and establishing their relevance across multiple niche dimensions8, 9. Such lack of quantitative studies therefore limits our ability to determine which species and interactions are important to maintain the multiple functions of ecosystems10. Here we develop a framework -derived from a resource-consumer-function tensor analysis-that bridges these gaps by framing biodiversity-ecosystem multifunctionality in terms of multilayer ecological network theory. Its application to recently collected ecological data -- reporting weighted interactions between plants, animals and fungi across multiple function types--allows to (i) unveil and quantify the existence of both (multi-functional) keystone species and a dual function keystoneness pattern, and (ii) project plants and functions into a similarity space where clear clusters emerge and the importance of weak links is manifested. This dual insight from species and functional perspectives will better guide conservation efforts to reduce biodiversity loss.

ecology↗

bioRxiv2021

Plant-insect chemical communication in ecological communities: an information theory perspective

Cross-species communication, where signals are sent by one species and perceived by others, is one of the most intriguing types of communication that functionally links different species to form complex ecological networks. Yet, global changes and human activities can affect communication by increasing the fluctuations of species composition and phenology, altering signal profiles and intensity, and introducing noises. So far, most studies on cross-species communication have focused on a few specific species isolated from ecological communities. Scaling up investigations of cross-species communication to the community level is currently hampered by a lack of conceptual and practical methodologies. Here, we propose an interdisciplinary framework based on information theory to investigate mechanisms shaping cross-species communication at the community level. We use plants and insects, the cornerstones of most ecosystems, as a showcase; and focus on chemical communication as the key communication channel. We first introduce some basic concepts of information theory, then we illustrate information patterns in plant-insect chemical communication, followed by a further exploration of how to integrate information theory into ecological and evolutionary processes to form testable mechanistic hypotheses. We conclude by highlighting the importance of community-level information as a vehicle to better understand the maintenance of ecological systems, especially when facing rapid global changes.

ecology↗