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Animal Sciences Commons

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Full-Text Articles in Animal Sciences

Dynamic Observers For Unknown Populations, Chris Guiver, Nathan Poppelreiter, Richard Rebarber, Brigitte Tenhumberg, Stuart Townley Jun 2021

Dynamic Observers For Unknown Populations, Chris Guiver, Nathan Poppelreiter, Richard Rebarber, Brigitte Tenhumberg, Stuart Townley

Brigitte Tenhumberg Papers

Dynamic observers are considered in the context of structuredpopulation modeling and management. Roughly, observers combine a known measured variable of some process with a model of that process to asymptotically reconstruct the unknown state variable of the model. We investigate the potential use of observers for reconstructing population distributions described by density-independent (linear) models and a class of density-dependent (nonlinear) models. In both the density-dependent and -independent cases, we show, in several ecologically reasonable circumstances, that there is a natural, optimal construction of these observers. Further, we describe the robustness these observers exhibit with respect to disturbances and uncertainty in …


Spectral Properties Of A Non-Compact Operator In Ecology, Matthew Reichenbach, Richard Rebarber, Brigitte Tenhumberg Jan 2021

Spectral Properties Of A Non-Compact Operator In Ecology, Matthew Reichenbach, Richard Rebarber, Brigitte Tenhumberg

Brigitte Tenhumberg Papers

Ecologists have recently used integral projection models (IPMs) to study fish and other animals which continue to grow throughout their lives. Such animals cannot shrink, since they have bony skeletons; a mathematical consequence of this is that the kernel of the integral projection operator T is unbounded, and the operator is not compact. To our knowledge, all theoretical work done on IPMs has assumed the operator is compact, and in particular has a bounded kernel. A priori, it is unclear whether these IPMs have an asymptotic growth rate λ, or a stable-stage distribution ψ. In the case of a compact …