Effects of climatic variation and reproductive trade-offs vary by measure of reproductive effort in greater sage-grouse.Ecosphere 5(12):154. http://dx.doi.org/10.1890/ES14-00124.1Abstract. Research on long-lived iteroparous species has shown that reproductive success may increase with age, until the onset of senescence, and that prior reproductive success may influence current reproductive success. Such complex reproductive dynamics can complicate conservation strategies, especially for harvested species. Further complicating the matter is the fact that most studies of reproductive costs are only able to evaluate a single measure of reproductive effort. We systematically evaluated the effects of climatic variation and reproductive trade-offs on multiple reproductive vital rates for greater sage-grouse (Centrocercus urophasianus; sage-grouse), a relatively long-lived galliforme of conservation concern throughout western North America. Based on over a decade of field observations, we hypothesized that reproduction is influenced by previous reproductive success. We monitored hen reproductive activity from 1998 to 2010, and used generalized linear mixed models to assess effects of climate and previous reproductive success on subsequent reproductive success. Reproductive trade-offs manifested as chronic effects on subsequent reproduction and were not apparent in all measures of subsequent reproduction. Neither nest initiation nor clutch size were found to be affected by climatic variables (either year t À 1 or t) or previous reproductive success. However, both nest and brood success were affected by climatic variation and previous reproductive success. Nest success was highest in years with high spring snowpack, and was negatively related to previous brood success. Brood success was positively influenced by moisture in April, negatively associated with previous nest success, and positively influenced by previous brood success. Both positive and negative effects of previous reproduction on current year reproduction were observed, possibly indicating high levels of individual heterogeneity in female reproductive output. Our results support previous research in indicating that climatic variability may have significant negative impacts on reproductive rates.

No abstract

Research on iteroparous species has shown that reproductive success may increase with age until the onset of senescence. However, from the population perspective, increased reproductive success with age could be a consequence of withinindividual variation (e.g. ageing, breeding experience, foraging ability hypotheses), between-individual variation (e.g. individual heterogeneity, frailty, selection, delayed breeding hypotheses), or a combination thereof. We evaluated within-and between-individual variation in reproductive success of greater sage-grouse ( Centrocercus urophasianus ; sage-grouse), a galliforme of conservation concern throughout western North America. We monitored female reproductive activity from 1998 -2010 and used generalized linear mixed models incorporating within-subject centering to evaluate and separate within-and between-individual eff ects. We detected positive eff ects of within-individual variation on nest initiation and success where ageing increased the likelihood of both parameters, which appears to support the breeding experience and/ or foraging ability hypotheses. However, nest initiation was also aff ected by between-individual variation whereby the likelihood of initiation was higher for individuals with higher mean age (i.e. survived longer), as is predicted by the frailty and selection hypotheses. Our results indicate both within-and between-individual variation aff ect reproductive output of sage-grouse, but the eff ects of each varied by measure of reproductive output. Our results corroborate previous fi ndings that suggest population age parameters (i.e. cross-sectional) should be interpreted with caution due to potential entanglement of within-and between-individual processes. Moreover, the relative role and strength of within-and between-individual processes appeared to vary by measure of reproductive output in our results, which further emphasizes the need for longitudinal analysis of age eff ects, even in relatively short-lived iteroparous animals, to adequately interpret biological processes.

We detected heartworm (Dirofilaria immitis) in 37.2% of 212 coyotes ( Canis latrans ) collected from 28 counties in Florida, US, between February 2010 and April 2014. Adult coyotes had a higher prevalence (45.6% of 103) than juveniles (29% of 80), and there was no significant difference in prevalence between adult male and female coyotes. Adults demonstrated a higher prevalence of heartworm in northern counties (56% of 91) than in southern counties (23.1% of 121) and a higher prevalence in urban areas (58.1% of 31) than in rural areas (33.3% of 63). There was no significant difference in mean body weight between infected and uninfected adult males or females. Intensity ranged from 1 to 144 (x̄ =21.29, SD=23.89, n=77). Mixed-sex heartworm infections were found in 88.9% of positive hosts, where the female-to-male ratio of worms was 1.14:1 (n=27). No pathologic changes attributable to heartworm infection were seen. A subsample of heartworms was confirmed to be D. immitis by targeted PCR amplification and DNA sequencing. Of 25 samples submitted for genotyping eight sequence haplotypes were found, all of which were distinct from all publicly available sequences derived from heartworms collected from domestic dogs ( Canis lupus familiaris). These sequences revealed more polymorphisms than did previous samples of D. immitis, which provides a broader foundation for the possibility that the heartworms will develop resistance to anthelmintics.

The influence of harvest on wild populations has been the focus of substantial debate, and has widespread implications for the management of wild populations. Traditional views of harvest are based on density-dependent responses of populations to harvest. However, alternate mechanisms can and do induce compensation (e.g., individual heterogeneity). Selective harvest of successful females and their offspring is thought to occur in some grouse populations (e.g., blue grouse [Dendragapus spp.], greater sage-grouse [Centrocercus urophasianus]), and delaying harvest within a season has been proposed as a viable strategy to overcome this type of selective harvest. However, a recent examination regarding the effects of harvest on greater sage-grouse strongly criticized the recommendation of delayed harvest. Herein, we address the criticism of the delayed harvest strategy and provide an examination of projecting the effects of harvest in the face of individual heterogeneity using deterministic projection models. We demonstrate that under proportional harvesting strategies, given a fixed harvest rate, early additive harvest does not have a larger effect on the population than additive harvest later in the season. Moreover, we show that when higher quality individuals (i.e., individuals with higher survival and reproductive rates) are more susceptible to harvest, individual heterogeneity in harvest effects will induce depensatory dynamics when densitydependent effects are only additive. Conversely, even when density-dependent effects are additive, if lower quality individuals are more susceptible to harvest, heterogeneity will induce partial compensation. Reducing the selectivity of harvest on higher quality individuals (i.e., shifting harvest onto lower quality groups) could reduce the risk of artificial selection and induce partial compensation. Therefore, we recommend managers consider the spatiotemporal patterns of populations and time harvest to maximize the heterogeneity tradeoff between higher and lower quality individuals. Ó 2017 The Wildlife Society.