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Understanding the processes behind change in reproductive state along life-history trajectories is a salient research program in evolutionary ecology. Two processes, state dependence and heterogeneity, can drive the dynamics of change among states. Both processes can operate simultaneously, begging the difficult question of how to tease them apart in practice. The Neutral Theory for Life Histories (NTLH) holds that the bulk of variations in life-history trajectories is due to state dependence and is hence neutral: Once previous (breeding) state is taken into account, variations are mostly random. Lifetime reproductive success (LRS), the number of descendants produced over an individual’s reproductive life span, has been used to infer support for NTLH in natura. Support stemmed from accurate prediction of the population-level distribution of LRS with parameters estimated from a state dependence model. We show with Monte Carlo simulations that the current reliance of NTLH on LRS prediction in a null hypothesis framework easily leads to selecting a misspecified model, biased estimates and flawed inferences. Support for the NTLH can be spurious because of a systematic positive bias in estimated state dependence when heterogeneity is present in the data but ignored in the analysis. This bias can lead to spurious positive covariance between fitness components when there is in fact an underlying trade-off. Furthermore, neutrality implied by NTLH needs a clarification because of a probable disjunction between its common understanding by evolutionary ecologists and its translation into statistical models of life-history trajectories. Irrespective of what neutrality entails, testing hypotheses about the dynamics of change among states in life histories requires a multimodel framework because state dependence and heterogeneity can easily be mistaken for each other.

The rapid increase in abundance of lesser snow goose (LSG; Chen caerulescens caerulescens) numbers and their devastating effects on arctic and subarctic habitats has inspired much research on the use of population models for defining appropriate management policies. We use the not yet considered metapopulation approach to examine the elasticity of mid-continent LSG population dynamics to changes in underlying vital rates to determine whether management efforts aimed at decreasing burgeoning numbers should be reevaluated. After considering a variety of geographic scenarios in the metapopulation model, we found that changes in survival would still have a larger impact on population dynamics relative to equal proportionate changes in other vital rates, but where these changes geographically occur could be of critical importance. In some instances, changes in reproductive output could have notable effects on eventual abundance. These new findings suggest that spatial structure in demographic vital rates that underlie abundance distributions across locations and dispersal among colonies require additional research to help guide the management of LSG numbers.

International audience

Conserving viable large carnivore populations requires managing their interactions with humans in increasingly anthropogenic landscapes. Faced with declining budgets and escalating wildlife conflicts, agencies in North America continue to grapple with uncertainty surrounding the efficacy of socially divisive management actions such as harvest to reduce conflict. We used multistate capture–reencounter methods to estimate cause-specific mortality for a large sample (>3500) of American black bears Ursus americanus in north-western New Jersey, USA over a 33-year period. Specifically, we focused on factors that might influence the probability of bears being harvested, lethally managed, or dying from other causes. We further analysed temporal correlations between >26 000 human–black bear incidents reported between 2001 and 2013 and estimates of total mortality rates, and specifically, rates of harvest from newly implemented public hunts and lethal management. Adult females were twice as likely (0·163 ± 0·014) as adult males (0·087 ± 0·012) to be harvested during the study period. Cubs (0·444 ± 0·025) and yearlings (0·372 ± 0·022) had a higher probability of dying from other causes, primarily vehicle strikes, than adults (0·199 ± 0·008). Reports of nuisance behaviours in year t + 1 declined with increasing mortality resulting from harvest plus lethal management in year t (P = 0·028, R2 = 0·338). Adult bears previously designated as a nuisance and/or threat were more likely to be harvested (0·176 ± 0·025) than those never identified as a problem (0·109 ± 0·010). Across age classes, individuals assigned problem status, were significantly more likely to be lethally controlled. Synthesis and applications. Given continuing failures in conserving exploited carnivores, their recreational harvest and lethal management remain polarizing. Within this social-ecological system, the well-regulated harvest of carefully monitored black bear populations represents a pragmatic approach to achieve population objectives. Furthermore, the integration of harvest and incident-response management (both lethal and non-lethal practices) with educational programmes aimed at reducing anthropogenic attractants can result in subsequent reductions in problem behaviours reported.

Harvest indices are used by state wildlife management agencies to monitor population trends and set harvest quotas for furbearer species. Although harvest indices may be readily collected from hunters, the reliability of harvest indices for monitoring demography and abundance of the harvested species is rarely examined, particularly amongst large carnivores. The overall objective of this study was to assess whether cougar (Puma concolor) harvest statistics collected by wildlife managers were correlated with changes in cougar demography, mainly survival rates and abundance. We estimated key demographic parameters for 2 cougar populations in Utah over 17 years during which we monitored 235 radio-collared cougars. We then compared these demographic parameters to harvest statistics provided by the Utah Division of Wildlife Resources over the same time period for the Oquirrh-Stansbury (lightly harvested population) and Monroe (heavily harvested population) harvest management units. In the Oquirrh-Stansbury unit, the percent of harvested cougars >6 years old was positively correlated with annual survival, indicative of a population experiencing several years of high survival resulting in an older age structure. Percent of permits filled and cougar abundance were also significantly correlated, suggesting higher hunting success with increased density. In the Monroe management unit, the annual percent of permits filled was correlated with changes in overall annual survival and male and female annual survival. Of utmost importance, pursuit success (cougars treed/day) increased with the number of cougars on the unit suggesting that pursuit indices may be an informative metric for wildlife managers to determine cougar population trends. Because both management units were subjected to contrasting mortality regimes, results provided by this assessment could potentially be applied to additional management areas sharing similar ecological characteristics and harvest metrics. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.