Biomedical subjects

Bruce C Robertson

Publications and source records attributed to Bruce C Robertson.

2 recordsLinked to original sources

PubMed2006

Sex allocation theory aids species conservation.

Supplementary feeding is often a key tool in the intensive management of captive and threatened species. Although it can increase such parameters as breeding frequency and individual survival, supplementary feeding may produce undesirable side effects that increase overall extinction risk. Recent attempts to increase breeding frequency and success in the kakapo Strigops habroptilus using supplementary feeding inadvertently resulted in highly male-biased chick sex ratios. Here, we describe how the inclusion of sex allocation theory has remedied this conservation dilemma. Our study is the first to manipulate chick sex ratios in an endangered species by altering maternal condition and highlights the importance of incorporating evolutionary theory into modern conservation practice.

Animals↗

PubMed2004

Moa were many.

Until a few hundred years ago, New Zealand hosted several species of flightless ratite birds, collectively known as the moa. We have used mitochondrial sequence data for Dinornis, the largest of the moa, and new coalescent approaches to estimate its population size prior to human arrival ca. 1000-6000 years BP. We show that, as little as 1000 years ago, Dinornis numbered between 300,000 and 1.4 million and that the standing population of all moa species was ca. 3-12 million. This estimate is an order of magnitude larger than the accepted population estimate (ca. 159,000) for all moa species at the arrival of humans and suggests that moa numbers had already declined prior to human settlement.

Animals↗