The life-history tactics of mustelids, and their significance for predator control and conservation in New Zealand

Abstract

Intensive predator control on game estates in 19th-century England is believed to be largely responsible for the decline of two large native mustelids, the pine marten and polecat. Two small, related, species, the stoat and weasel, were also killed in large numbers but are still common in England, and have been introduced into New Zealand. The theory of life-history tactics offers an explanation for the different effects of persecution on large and small mustelids. It also suggests that stoats in New Zealand national parks cannot be exterminated by trapping, and that the first priority for the conservation of rare native birds such as the takahe is active management to stimulate breeding.

Are low reproductive rates characteristic of New Zealand's native terrestrial birds? Evidence from the allometry of nesting parameters in altricial species

“…Furthermore, gigantism, a trait allometrically related to low rates of reproduction (Livezey 1992), is particularly prevalent in the New Zealand avifauna (Trevelyan & Read 1989;Daugherty et al 1993). Whether the frequency of such features is attributable to environmental saturation is unclear, but the absence of mammalian predators from New Zealand prior to human settlement and the disastrous consequences of their introduction (King & Moors 1979;King 1984;O'Donnell 1996;Holdaway 1999) suggests such a possibility.…”

“…Low reproductive rates and compensatory greater investment in individual young have often been considered a feature of the New Zealand avifauna (King & Moors 1979;Moors 1983;King 1984;Daugherty et al 1993;Gill & Moon 1999;Holdaway 1999). This may take the form of infrequent nesting, small clutches, large eggs and hatchlings or long periods of incubation, nestling and fledglingdependence (Niethammer 1970;Reid 1971;McLean & Miskelly 1988;Williams et al 1991;Powlesland et al 1992;Elliott et al 1996).…”

The evolution of intelligence in mammalian carnivores

“…raccoons [54][55][56][57]), several troubling exceptions remain that this hypothesis cannot explain. For example, solitary weasels have some of the largest relative brain sizes in the entire carnivore order [58], yet they are born in large litters, mature very rapidly, have no allo-parenting, and lead totally solitary lives except when mating [59,60].…”

Field experiments on the trapping of stoats (Mustela erminea)

“…The two most important of the unstated assumptions behind such a policy are that it is possible to reduce a local population of stoats by trapping, and that predation by stoats controls the population densities of the birds in question. There is some reason to doubt the first assumption, at least over the long term (King & Moors 1979), and data concerning the second are inadequate. Formulation of a rational management policy requires information on many aspects of the biology of the protected species besides the possible value of various forms of predator control.…”