A common choice for a probability distribution of a probability is the beta distribution. It has the required support between 0 and 1, and with its two parameters we can obtain a pretty wide qualitative range for the probability density function. What should we do if we want to create correlated probabilities? We might look for some kind of multivariate generalisation of the beta distribution, … Continue reading Moments for a bivariate beta distribution
SMBC has a funny comic that’s also about the Principle of Indifference. Continue reading Comic about PI
Here’s a nice video I stumbled upon about Lisa Aubry’s group’s work at Utah State Uni. Climate change is having a positive effect on uinta ground squirrels, allowing them to fatten-up and attain weights higher than those recorded historically. This population is survival limited, and survival probability is higher the fatter the squirrels are, so abundance responds positively to this climate change. I can’t handle … Continue reading Bad for birds, good for squirrels
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
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
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
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?
Climate change has caused an advance in phenological events in many species. In migratory birds, the effects of warming flow causally up the trophic levels. For example, warmer temperatures lead to earlier plant phenology (e.g. budding), which leads to earlier peaks in the abundance of foods (e.g. insect larva) that are important to raising nestlings, which puts pressure upon birds to advance their own breeding … Continue reading Do birds sometimes respond to warming temperatures by delaying their phenology?
Climate change has caused an advance in phenological events in many species (Forchhammer et al. 1998, Chmielewski & Rotzer 2001, Parmesan & Yohe 2003, Edwards & Richardson 2004, Menzel et al. 2006, Beebee 2009). In migratory birds, the effects of warming flow causally up the trophic levels. For example, warmer temperatures lead to earlier plant phenology (e.g. budding) (Menzel et al. 2006, Schwartz et al. … Continue reading The problem of arrival time and prelaying period in migratory birds
McDonald-Madden (2010; TREE): Is monitoring worthwhile? The benefits of the information gained from monitoring do not always outweigh the costs of acquiring it. For example, if one’s management strategy is not dependent upon the state of the system, one does not need to monitor. Or if one is unsure about the cause of decline, it may make more sense to spend resources researching that rather … Continue reading Monitoring for conservation