KNOWLEDGE BASE

This article gave an update, as of 1993, on the case of invasive beavers in Tierra del Fuego, Argentina. Suitable habitat and a lack of natural predators had allowed beaver populations to grow rapidly, colonising several islands in the Magallanico Archipelago. Their presence had transformed the forest ecosystems, creating wetlands, raising water tables, and altering the biochemical composition of riparian areas. Please note, this resource is not open-access.

Scandinavian beavers faced a genetic bottleneck due to overhunting towards the end of the 1800s, with the Swedish population nearly extinct. After reintroductions from Norway around 1930, the population had grown to 100,000 at the time of this study. The study showed that this growing population had low genetic diversity, showing that beaver reintroduction efforts can work even with limited genetic variation.

This experiment sought to better understand how scientists should interpret wolf poo in order to understand wolves' diet. It did this by feeding captive wolves various prey and testing their poo. The study resulted in a new recommended method, and showed that previous studies may have been over-estimating the prevalence of very small prey (such as beaver kits) in wolf diets. Please note, this resource is not open-access.

Tularaemia is a disease caused by a bacterium which has two subspecies: Type A and the milder Type B. This paper explained how the disease had been reported in over 250 animal species. In North America, beavers were reported as being important carriers of the type B bacterium, which is mainly water-borne. When it occurs, the disease normally presents as an epidemic, spreading through contact with infected animals, contaminated water, or vectors like ticks and mosquitoes.

Researchers studied 32 forested stream areas in Ontario, Canada to develop models which predict nutrient flow into lakes. They found that nutrients landing in these stream areas from the air usually exceeded what was exported. Where export levels of phosphorus and nitrogen were high, beaver ponds and peat areas were often identified as the likely sources. Please note, this resource is not open-access.