Sebastian Schreiber
@sebastianschreiber.bsky.social
1.8K followers 390 following 200 posts
Population biologist and mathematician wrestling with the complexities of nature armed with the theories of stochastic processes and dynamical systems. Dynamics of Ecological and Evolutionary Processes Lab https://schreiber.faculty.ucdavis.edu
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sebastianschreiber.bsky.social
Delighted to see the online publication of my paper "Coexistence and extinction in flow-kick systems: An invasion growth rate approach" in the 50th anniversary issue of the Journal of Mathematical Biology. 1/5

link.springer.com/article/10.1...
Coexistence and extinction in flow-kick systems: An invasion growth rate approach - Journal of Mathematical Biology
Natural populations experience a complex interplay of continuous and discrete processes: continuous growth and interactions are punctuated by discrete reproduction events, dispersal, and external disturbances. These dynamics can be modeled by impulsive or flow-kick systems, where continuous flows alternate with instantaneous discrete changes. To study species persistence in these systems, an invasion growth rate theory is developed for flow-kick models with state-dependent timing of kicks and auxiliary variables that can represent stage structure, trait evolution, or environmental forcing. The invasion growth rates correspond to Lyapunov exponents that characterize the average per-capita growth of species when rare. Two theorems are proven that use invasion growth rates to characterize permanence, a form of robust coexistence where populations remain bounded away from extinction. The first theorem uses Morse decompositions of the extinction set and requires that there exists a species with a positive invasion growth rate for every invariant measure supported on a component of the Morse decomposition. The second theorem uses invasion growth rates to define invasion graphs whose vertices correspond to communities and directed edges to potential invasions. Provided the invasion graph is acyclic, permanence and extinction are fully characterized by the signs of the invasion growth rates. Invasion growth rates are also used to identify the existence of extinction-bound trajectories and attractors that lie on the extinction set. To demonstrate the framework’s utility, these results are applied to three ecological systems: (i) a microbial serial transfer model where state-dependent timing enables coexistence through a storage effect, (ii) a spatially structured consumer-resource model showing intermediate reproductive delays can maximize persistence, and (iii) an empirically parameterized Lotka-Volterra model demonstrating how disturbance can lead to extinction by disrupting facilitation. Mathematical challenges, particularly for systems with cyclic invasion graphs, and promising biological applications are discussed. These results reveal how the interplay between continuous and discrete dynamics creates ecological outcomes not found in purely continuous or discrete systems, providing a foundation for predicting population persistence and species coexistence in natural communities subject to gradual and sudden changes.
link.springer.com
sebastianschreiber.bsky.social
INKTOBER 2025
Day 7 - Starfish (catching a butterpi)
#inktober2025 #starfish #pi
pen and ink drawing of Patrick Starfish trying to catch a flying Pi symbol
Reposted by Sebastian Schreiber
theferrarilab.bsky.social
Come and work with us! Review of candidates will begin ~1 October with rolling consideration thereafter. If you are unable to apply early, contact the search committee chair (me) to discuss timelines.
Reposted by Sebastian Schreiber
evodynamics.bsky.social
Looking forward to this! A non-Elsevier alternative to Theoretical Population Biology / Journal of Theoretical Biology
stanfordpress.bsky.social
Population Biology Modeling & Theory (PBMT) is a peer-reviewed journal reporting advances in modeling and theory within population biology. Its scope spans demography, ecology, epidemiology, evolutionary biology, population genetics, and phylogenetics. PBMT will be online soon.
Reposted by Sebastian Schreiber
steve-lucas.bsky.social
INKTOBER 2025
Day 7 - Starfish

#Inktober #Inktober2025 #Sketch #ink #Art #Day7 #Starfish
INKTOBER 2025
Day 7 - Starfish

#Inktober #Inktober2025 #Sketch #ink #Art #Day7 #Starfish
sebastianschreiber.bsky.social
INKTOBER 2025
Day 4 - MURKY
#inktober2025
pen and ink drawing of an octobus in a fountain pen ink bottle with some of its tentacles reaching outward to hold onto a quill
Reposted by Sebastian Schreiber
abara71628.bsky.social
気まぐれゆるゆるインクトーバー
5.Deer/シカ
6.Pierce/突き刺す、貫通する
#inktober2025

よし…アレでいくかっ…!合体!!
sebastianschreiber.bsky.social
INKTOBER 2025
Day 3 - CROWN
#inktober2025
Reposted by Sebastian Schreiber
steve-lucas.bsky.social
INKTOBER 2025
Day 2 - Weave

#Inktober #Inktober2025 #Sketch #ink #Art #Day2 #Weave
INKTOBER 2025
Day 2 - Weave 

#Inktober #Inktober2025 #Sketch #ink #Art #Day2 #Weave
Reposted by Sebastian Schreiber
biologyjoe87.bsky.social
We use invasion growth rates to develop the "Community Disassembly Graph". Nodes represent coexisting communities and directed edges represent transitions from one community composition to another due to extinction. We can use this graph to identify possible secondary extinctions. (4/X)
Reposted by Sebastian Schreiber
biologyjoe87.bsky.social
We apply recently-developed techniques from dynamical systems theory and modern coexistence theory to identify (1) WHEN and WHY secondary extinctions occur. We demonstrate that invasion growth rates (per capita growth rates of species when rare) can achieve these goals! (3/X)
Reposted by Sebastian Schreiber
biologyjoe87.bsky.social
Coexistence outcomes often depend on the complex interplay of species interactions. Consequently in some cases, the extinction of one species can trigger the loss of another, a process known as secondary extinction, as explained by a plaque I came across at the Bronx Zoo. (2/X)
Reposted by Sebastian Schreiber
biologyjoe87.bsky.social
Excited to share a new pre-print in collaboration with @sebastianschreiber.bsky.social, "Using Modern Coexistence Theory to understand community disassembly"! We set out to understand how techniques used to study coexistence can be extended to understand community disassembly. (1/X)
Using modern coexistence theory to understand community disassembly
Community disassembly examines how species extinction alters ecological communities. Sometimes, the extinction of one species can trigger the loss of others, known as secondary extinction. These secon...
www.biorxiv.org
Reposted by Sebastian Schreiber
corriemoreau.bsky.social
UPDATE: The 2025-2026 list of faculty and postdoc positions in ecology and evolutionary biology is out! Be sure to check out this active and helpful community run resources! docs.google.com/spreadsheets...
ecoevojobs.net 2025-26
docs.google.com
Reposted by Sebastian Schreiber
rafamarcondes.bsky.social
🚨🚨 DREAM JOB ALERT 🚨 🚨
scottpegan.bsky.social
The Dept. of BioSciences at #RiceUniversity, in Houston, Texas, invites applications for a tenure-track assistant professor position in Evolutionary Biology, with a preferred focus on organismal responses to environmental change. Please RT!

Apply: apply.interfolio.com/173889
Apply - Interfolio {{$ctrl.$state.data.pageTitle}} - Apply - Interfolio
apply.interfolio.com
Reposted by Sebastian Schreiber
seemasheth.bsky.social
NSF GRFP solicitation is finally up. Life Sci deadline extended to Nov 10 but 2nd year grad students no longer eligible www.nsf.gov/funding/oppo...
NSF Graduate Research Fellowship Program (GRFP)
www.nsf.gov
sebastianschreiber.bsky.social
Applications are provided to serial transfer models, data-based Lotka-Volterra models with mortality pulses, & spatial models of consumers with reproductive pulses. They illustrate the storage effect, unexpected extinctions, and the importance of the timing between reproductive pulses. 5/5
sebastianschreiber.bsky.social
When the invasion graph is acyclic, coexistence occurs iff every subcommunity has at least one missing species with a positive invasion growth rate (IGR). Alternatively, if a subcommunity is permanent and all missing species have negative IGRs, there is an extinction attractor 4/5
sebastianschreiber.bsky.social
I introduce the average per-capita growth rates associated with any stationary community state (i.e., ergodic measure) and a directed graph (the invasion graph) representing potential transitions between community states due to invasions of one or more species. 3/5
sebastianschreiber.bsky.social
I consider models that track species densities and auxiliary variables and that alternate between continuous-time processes (the flow) and discrete updates (the kick). The time between discrete updates can be state-dependent, e.g., serial transfers at critical optical densities. 2/5
sebastianschreiber.bsky.social
Delighted to see the online publication of my paper "Coexistence and extinction in flow-kick systems: An invasion growth rate approach" in the 50th anniversary issue of the Journal of Mathematical Biology. 1/5

link.springer.com/article/10.1...
Coexistence and extinction in flow-kick systems: An invasion growth rate approach - Journal of Mathematical Biology
Natural populations experience a complex interplay of continuous and discrete processes: continuous growth and interactions are punctuated by discrete reproduction events, dispersal, and external disturbances. These dynamics can be modeled by impulsive or flow-kick systems, where continuous flows alternate with instantaneous discrete changes. To study species persistence in these systems, an invasion growth rate theory is developed for flow-kick models with state-dependent timing of kicks and auxiliary variables that can represent stage structure, trait evolution, or environmental forcing. The invasion growth rates correspond to Lyapunov exponents that characterize the average per-capita growth of species when rare. Two theorems are proven that use invasion growth rates to characterize permanence, a form of robust coexistence where populations remain bounded away from extinction. The first theorem uses Morse decompositions of the extinction set and requires that there exists a species with a positive invasion growth rate for every invariant measure supported on a component of the Morse decomposition. The second theorem uses invasion growth rates to define invasion graphs whose vertices correspond to communities and directed edges to potential invasions. Provided the invasion graph is acyclic, permanence and extinction are fully characterized by the signs of the invasion growth rates. Invasion growth rates are also used to identify the existence of extinction-bound trajectories and attractors that lie on the extinction set. To demonstrate the framework’s utility, these results are applied to three ecological systems: (i) a microbial serial transfer model where state-dependent timing enables coexistence through a storage effect, (ii) a spatially structured consumer-resource model showing intermediate reproductive delays can maximize persistence, and (iii) an empirically parameterized Lotka-Volterra model demonstrating how disturbance can lead to extinction by disrupting facilitation. Mathematical challenges, particularly for systems with cyclic invasion graphs, and promising biological applications are discussed. These results reveal how the interplay between continuous and discrete dynamics creates ecological outcomes not found in purely continuous or discrete systems, providing a foundation for predicting population persistence and species coexistence in natural communities subject to gradual and sudden changes.
link.springer.com
Reposted by Sebastian Schreiber
felixled.bsky.social
Open-rank open-area faculty search in the Department of Mathematics at the University of Illinois Urbana-Champaign.

Application deadline: November 3, 2025.

Please share widely!

www.mathjobs.org/jobs/list/26...
MathJobs from the the American Mathematical Society
Mathjobs is an automated job application system sponsored by the AMS.
www.mathjobs.org
Reposted by Sebastian Schreiber
whistberry.bsky.social
It's dangerous to go alone....so what invertebrate are you taking with you?

#Invertefest

This guy
Drawing of a praying mantis with front legs and wings outspread in a charmingly threatening pose. Its wings are translucent and tinged with the pink, white, and blue colors of the trans flag.
Reposted by Sebastian Schreiber
gautamdey.bsky.social
Final year PhD students, I know you’re desperately trying to finish experiments/revisions/submissions/write a thesis & just survive - but please spare a few minutes to apply to your dream postdoc labs.

It easily takes A YEAR from first contact, even if everything goes to plan on both sides.