The Man Who Planted Oaks

I am sometimes asked how long I have been keeping dartfrogs. This is my answer.

Many years ago I first read the story of The Man Who Planted Trees. While this is a work of fiction, I have become that man.

Several years after I had begun keeping dartfrogs, I collected acorns from my favourite oak trees (one on Bournville Green, one big boundary oak near my house, and a few others. I sowed them in pots and waited for the frost. The first Spring there was no sign of life, but in the second year, shoots appeared. After another year, I planted the saplings out at the bottom of my garden.

This morning, many years later, I collected bags of tannin-rich leaves from my oak trees, enough to last me for a year.

Many people keep dartfrogs for a shot time, get bored and stop. Planting oaks is a sign that I am serious about this.

What Drives Chytrid Infections in Newt Populations?

The pathogenic chytrid fungus Batrachochytrium dendrobatidis (Bd) is considered responsible for the population declines and extinctions of hundreds of amphibian species worldwide. The panzootic was likely triggered by human-assisted spread, but once the pathogen becomes established in a given region, its distribution is probably determined by local drivers. To assess the relative importance of potential drivers of infection in red-spotted newts (Notophthalmus viridescens), we measured Bd levels in 16 populations throughout central Pennsylvania. Infected individuals were detected in all but four populations, indicating that Bd is widespread in this region. We quantified local factors hypothesized to influence Bd, and found that infection levels were best predicted by the proportion of the pond substrate consisting of leaf litter or vegetation, along with a significant effect of water temperature. Bd infection in amphibians is temperature-dependent, and one possible explanation of the apparent substrate effect is that tree cover and vegetation provide shade, reducing the availability of shallow, warm-water patches in which newts might reduce or clear Bd infections. Alternatively, leaf litter and emergent vegetation might increase Bd infection more directly, perhaps by providing substrates for environmental growth of the fungus. We also observed a curvilinear relationship between Bd load and snout-vent length (a proxy for age), hinting that newts might develop acquired resistance to Bd infection. Though correlational, these results add to a growing body of evidence suggesting that environmental temperature is an important driver of Bd infection dynamics.

What Drives Chytrid Infections in Newt Populations? Associations with Substrate, Temperature, and Shade. Ecohealth. Dec 2 2010