Author: nadiahkristensen

code, python, sage

Import self-made Sage modules and functions into Sage script?

Let’s say that I have created a bunch of Sage code — Sage functions etc. — that I wish to reuse by importing into various Sage scripts. In straight Python, one would put these functions into their own separate file and import them using the usual from foo import funcname as localfuncname type procedure. It is unclear to me what the proper procedure for doing … Continue reading Import self-made Sage modules and functions into Sage script?

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code, python, qualitative modelling

“ValueError: expected a DNF expression” when trying espresso_exprs example from pyeda docs

I’ve recently been working on a qualitative modelling project where I am trying to uncover “truths” about the response of species in an ecosystem to control of invasive species. Long story short, I’ve been looking into various boolean minimisation techniques. I’ve been playing with Python EDA, a Python library that I think provides a front-end to the Robert Brayton and Richard Rudell espresso heuristic logic … Continue reading “ValueError: expected a DNF expression” when trying espresso_exprs example from pyeda docs

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qualitative modelling

The Principle of Indifference in ecological modelling

(Update April 2019: a paper on the topic below has now been published in MEE) Qualitative modelling Qualitative modelling (QM) holds the promise of obtaining predictions from dynamical models even when we don’t have all the data needed to parameterise them. How does QM achieve this? In short, the idea is to explore the range of possible parameter values to create an ensemble of possible … Continue reading The Principle of Indifference in ecological modelling

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conservation

Biodiversity versus ecosystem services

This is a brief summary of a debate about the relationship between biodiversity conservation (BD) and managing for ecosystem services (ES) and the proper role of conservation. The debate centers around an article by Kareiva and Marvier (2012) and the discussion that followed. Some threads of the discussion were: A reply by Soule (2013), followed by Marvier (2014), and those below. A reply by Miller … Continue reading Biodiversity versus ecosystem services

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evolution, phenology, stochasticity

On phenology and bet-hedging

Environmental fluctuations may cause natural selection to favor phenologies that systematically deviate from the resource maximizing strategy. In temporally variable environments, because fitness is taken from the geometric (not arithmetic) mean growth rate (Gillespie, 1974), this permits the evolution of bet-hedging strategies (Simons, 2011), which are strategies that maximises total fitness by reducing temporal variation at the cost of arithmetic mean fitness (Ripa et al. … Continue reading On phenology and bet-hedging

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evolution, local adaptation, phenology, recently read

The interesting case of blue tits in France

I’ve recently been reading about a several decade long study centred around blue tits in France and on the island of Corsica. The work is being carried out by a group in the evolutionary ecology unit at the Centre D’Ecologie Fonctionnelle & Evolutive and it crosses over all kinds of interesting areas of ecology and evolution. The mainland study area is dominated by deciduous habitat … Continue reading The interesting case of blue tits in France

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climate change

The IPCC First Assessment Report and phenological synchrony

I just found a pretty early reference to the possibility of climate change leading to asynchrony between plant and animal phenology. From Chapter 10 page 295 of Climate Change: The IPCC Scientific Assessment (1990) Of crucial importance in plant community functioning is the synchronous operation of the life cycles of interacting plants, animals and soil organisms. Complex synchronies are found in communities in which the … Continue reading The IPCC First Assessment Report and phenological synchrony

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climate change, phenology

Are caterpillars really that important?

Typically the the kinds of models that I’m interested in assume that fledging rate is very dependent upon a phenological match between nestlings’ peak food requirements and the peak in caterpillar abundance. However I recently read a study by Cholewa and Wesołowski (2011; Acta Ornithologica) pointing out that, while literature shows that blue tits and marsh tits are indeed strongly dependent upon this food type, … Continue reading Are caterpillars really that important?

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