Staff

LAJAAITI Ismaël

	Theme(s) : Spatial dynamics, connectivity, habitat and functional area Trophic interaction Ecosystems assessment and multiple anthrophic pressure Email : ismael.lajaaiti@inrae.fr Address: UMR DECOD, 65 rue de Saint-Brieuc, Bât. 19, CS 84215, 35042 Rennes Cedex, France Keywords : Ecologie spatiale / Interactions trophiques / Réseaux d’interaction / Stabilité des réseaux / Méta-écosystèmes / Poissons / Modèles de réseaux / Modélisation statistique

Research

My research aims to understand how anthropogenic pressures alter ecosystems. The challenge in addressing this question is twofold. First, species respond in different ways to the same disturbance due to variability in their life-history traits. Second, species form complex networks, which make their dynamics intertwined and difficult to predict. I combine theoretical models and data analysis to address the following question: How do species interactions shape the effects of environmental pressures on ecological systems?

In particular, my current postdoctoral project focuses on quantifying the effects of dams and nutrient enrichment on food-web structure across France.

Current projects

The influence of spatial fluxes on meta-ecosystem dynamics: theoretical perspectives and practical applications along the river-sea continuum

RIVERSEA

Timeframe : 2025 - 2027
Keywords : cascades trophiques / Connectivité / Ecologie spatiale / Inférence de réseaux / Interactions trophiques / Réseaux d’interaction / Stabilité des réseaux / Stress abiotique / Barrages / Eutrophisation / Méta-communautés / Méta-écosystèmes / Poissons / Analyses de séries temporelles / Modélisation statistique

Past projects

Expertises

My expertise lies at the interface between theoretical ecology, network science, and data-driven ecological analysis. I have a strong background in theoretical ecology, particularly in the development and analysis of dynamical models to study species interactions and their impact on species stability. This includes extensive experience with network theory and food-web ecology.

I am currently developing expertise in spatio-temporal Bayesian modeling, with an emphasis on accounting for spatial auto-correlation in stream networks.

I also have strong programming skills, with experience in R, Python, and Julia, which I use for to develop open-source libraries for the scientific community.

Publications

Selection of Scientific Products

Leroy Amélie, Lajaaiti Ismaël, Lambert Sophia, Voznica Jakub, Pichler Maximilian, Morlon Hélène, Hartig Florian, Jacob Laurent (2025). Graph Neural Networks for Likelihood-Free Inference in Diversification Models. 2025

Ardichvili Alice, Loreau Michel, Onimus Thomas, Galiana Nuria, Lajaaiti Ismaël, Kéfi Sonia, Arnoldi Jean-François (2025). Beyond biomass: how interactions shape species’ importance for ecosystem functioning. 2025

Lajaaiti Ismaël, Kéfi Sonia, Loreau Michel, Ardichvili Alice, Arnoldi Jean-François (2025). Linking biotic interactions to species stability. 2025

Garcia-Callejas David, Thebault Elisa, Lajaaiti Ismael, Martins Lucas, Laux Louise, Kefi Sonia (2025). Ecological networks across interaction types are modular and highly driven by sampling intensity at biogeographical scales. 2025

Aguadé-Gorgorió Guim, Lajaaiti Ismaël, Arnoldi Jean‐françois, Kéfi Sonia (2025). Unpacking sublinear growth: diversity, stability and coexistence. Oikos, 2025, 2025 (1), pp.e10980. ⟨10.1111/oik.10980⟩

Lajaaiti Ismaël, Bonnici Iago, Kéfi Sonia, Mayall Hana, Danet Alain, Beckerman Andrew, Malpas Thomas, Delmas Eva (2025). EcologicalNetworksDynamics.jl: A Julia package to simulate the temporal dynamics of complex ecological networks. Methods in Ecology and Evolution, 2025, 16 (3), pp.520-529. ⟨10.1111/2041-210X.14497⟩

Pichon Benoît, Kéfi Sonia, Loeuille Nicolas, Lajaaiti Ismaël, Gounand Isabelle (2024). Integrating ecological feedbacks across scales and levels of organization. Ecography, In press, ⟨10.1111/ecog.07167⟩

Lajaaiti Ismaël, Kéfi Sonia, Arnoldi Jean-François (2024). How biotic interactions structure species’ responses to perturbations. Proceedings of the Royal Society B: Biological Sciences, 2024, 291 (2032), ⟨10.1098/rspb.2024.0930⟩

Lajaaiti Ismaël, Bonnici Iago, Kéfi Sonia, Mayall Hana, Danet Alain, Beckerman Andrew, Malpas Thomas, Delmas Eva (2024). EcologicalNetworksDynamics.jlA Julia package to simulate the temporal dynamics of complex ecological networks. 2024, ⟨swh:1:dir:d2734fcc52ebd24cd81cfca33dd2929d91aebcd9;origin=https://hal.archives-ouvertes.fr/hal-04623870;visit=swh:1:snp:ca85589402311199e17dc9de31c5f45c61829868;anchor=swh:1:rel:dcbdd5bc275519771811f18fdd76dfff23355b81;path=/⟩