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Biology subjects

Gelber, S.

Publications and source records attributed to Gelber, S..

3 recordsLinked to original sources

Disturbance and landscape characteristics interactively drive dispersal strategies in continuous and fragmented metacommunities

Habitat fragmentation, driven by human activities, disrupts habitat connectivity and alters ecological processes through geometric and demographic fragmentation effects. Dispersal plays a fundamental role in shaping the distribution, abundance, and persistence of species in modified landscapes. While previous research looked at the evolution of dispersal strategies at the species level, community-level dynamics remain underexplored. Species exhibit diverse dispersal strategies to persist in modified landscapes, yet predicting how these strategies interact at the community level requires a more integrated approach. This study employed an individual-based simulation model to explore how fragmentation and other landscape characteristics influence community-level dispersal strategies. We tested the effects of varying fragmentation levels, environmental autocorrelation, habitat amount, and disturbance levels on the emerging distribution of dispersal distances within a community in modified and continuous landscapes. We hypothesised that fragmentation and other spatial patterns would significantly shape community composition, favouring particular dispersal strategies under specific environmental conditions. The findings reveal that higher disturbance levels and greater habitat amount increased the community-weighted mean of dispersal distance, while fragmentation showed only minor variation. Additionally, low autocorrelation was associated with the highest community-weighted mean of dispersal distance. These results highlight the importance of considering community-level dynamics when predicting ecosystem responses to landscape modification. By clarifying how landscape structure and disturbance shape community-level dispersal strategies, this study advances our understanding of the mechanisms underlying species persistence and community structure in modified landscapes.

ecology↗

Geometric and demographic effects explain contrasting fragmentation-biodiversity relationships across scales

There is consensus that habitat loss is a major driver of biodiversity loss, while the effects of fragmentation, given a constant total habitat amount, are still debated. Here, we use a process-based metacommunity model to show how strongly scale- and context-dependent fragmentation-biodiversity relationships can emerge from the interplay of two types of fragmentation effects - geometric and demographic. Geometric effects arise from the spatial distribution of species and landscape modification, whereas demographic effects reflect long-term changes in species demographic rates following landscape modification. We introduce a novel approach to partitioning these two types of effects and assess how key ecological processes and factors, such as dispersal, habitat heterogeneity, and edge effects, influence geometric, demographic, and net fragmentation effects across spatial scales. We conclude that the framework of geometric and demographic effects can reconcile previous apparently conflicting results and hopefully unlock and advance the debate on biodiversity change in modified landscapes.

ecology↗

Discovery of a multipotent cell type from the term human placenta

We identify a population of multipotent CDX2 cells from term human placentas with clonal expansion, migratory capacity, and immune-privileged transcriptional profiles. Isolated from 180 healthy pregnancies, these cells differentiate into cardiomyocyte and vascular lineages in vitro and in vivo. Single-cell RNA sequencing uncovers distinct cardiogenic and vasculogenic subpopulations, along with immune-modulatory and chemotactic programs, providing a blueprint for precision-guided cardiovascular cell therapy. In a NOD/SCID myocardial infarction model, CDX2 cells restore cardiac function, and clonal propagation preserves their cardiovascular differentiation potential. These findings position placental CDX2 cells as an ethically accessible, regenerative platform for targeted treatment of cardiovascular disease.

cell biology↗