Forbidden fruit: human settlement and abundant fruit create an ecological trap for an apex omnivore

Abstract

Summary 1.Habitat choice is an evolutionary product of animals experiencing increased fitness when preferentially occupying high-quality habitat. However, an ecological trap (ET) can occur when an animal is presented with novel conditions and the animal's assessment of habitat quality is poorly matched to its resulting fitness. 2. We tested for an ET for grizzly (brown) bears using demographic and movement data collected in an area with rich food resources and concentrated human settlement. 3. We derived measures of habitat attractiveness from occurrence models of bear food resources and estimated demographic parameters using DNA mark-recapture information collected over 8 years (2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013). We then paired this information with grizzly bear mortality records to investigate kill and movement rates. 4. Our results demonstrate that a valley high in both berry resources and human density was more attractive than surrounding areas, and bears occupying this region faced 17% lower apparent survival. Despite lower fitness, we detected a net flow of bears into the ET, which contributed to a study-wide population decline. 5. This work highlights the presence and pervasiveness of an ET for an apex omnivore that lacks the evolutionary cues, under human-induced rapid ecological change, to assess tradeoffs between food resources and human-caused mortality, which results in maladaptive habitat selection.

The Gordian knot of mountain lion predation and bighorn sheep

“…Grizzly bear and wolf distribution overlapped nearly all Rocky Mountain bighorn sheep range and some desert bighorn ranges (Young and Goldman , Lamb et al ). These 2 predators were absent only from the most xeric parts of Mexico, western Arizona, California, and Nevada (Young and Goldman , Lamb et al ). The extirpation of wolves (Young and Goldman ) and near extirpation of grizzly bears (Brown , Lamb et al ) is well documented.…”

“…These 2 predators were absent only from the most xeric parts of Mexico, western Arizona, California, and Nevada (Young and Goldman , Lamb et al ). The extirpation of wolves (Young and Goldman ) and near extirpation of grizzly bears (Brown , Lamb et al ) is well documented. Mountain lions are subordinate to wolves and bears (Boyd and Neale , Kortello et al , Ruth et al , Elbroch et al ) and much like the well documented response of subordinate coyotes to the absence of wolves (Berger and Gese , Merkle et al ), mountain lions almost certainly have responded numerically to competitive release from these 2 dominate carnivores.…”

Effects of habitat quality and access management on the density of a recovering grizzly bear population

“…ungulate hunting, motorised recreation, etc.). In contrast to hunting mortalities, which are regulated, non‐hunting mortalities are difficult to quantify and control (Lamb, Mowat, McLellan, Nielsen, & Boutin, ). Since the cessation of the hunt in 1995, only 13 human‐caused grizzly bear mortalities have been recorded in the Kettle–Granby GBPU (1995–2015), largely due to human–bear conflicts (61%) and poaching (31%).…”

Elevated Immune Gene Expression Is Associated with Poor Reproductive Success of Urban Blue Tits

“…Nonetheless, urban environments are linked to reductions in fitness and health in a substantial number of organisms (Chamberlain et al, 2009;Murray et al, 2015). Hence, urban habitats are sometimes considered ecological traps which attract organisms, for example by anthropogenic food availability, but are insufficient for supporting successful rearing of offspring (Plummer et al, 2013;Sumasgutner et al, 2014;Lamb et al, 2017). There is a need, therefore, to understand the mechanisms by which urbanization reduces reproductive success.…”