Ptarmigan in North America: Influence of Life History and Environmental Conditions on Population Persistence.

Abstract

ABSTRACT.-Three ptarmigan species (Willow Ptarmigan Lagopus lagopus, Rock Ptarmigan L. muta, and White-tailed Ptarmigan L. leucura) occupy the tundra habitats of North America. Willow and Rock Ptarmigan inhabit arctic and alpine regions of Canada and Alaska, while Whitetailed Ptarmigan occupy alpine habitats from Alaska and northern Canada south to New Mexico. Ptarmigan populations have relatively short generation times (1.7 to 2.62 years) with an annual fecundity of 0.4 to 2.04 female fledglings/female. In some populations, annual fecundity depends strongly on re-nesting to replace failed first clutches (predation rate usually >50%). We use demographic data from five study sites (38 study-years) to demonstrate that the life history of the North American ptarmigan varies from fast (r-selection/high fecundity) to slow life styles (Kselection/high survival). Willow Ptarmigan, living in sub-arctic and sub-alpine habitats, have a fast life history. Their populations are most strongly influenced by fecundity and survival of juveniles and yearling females. At the other end of the spectrum, Rock Ptarmigan have a slower life history with nearly 40% lower reproductive output, but over 20% higher adult survival rate. Interestingly, White-tailed Ptarmigan show within-species variation from fast to slow lifestyles across their latitudinal range. White-tailed Ptarmigan in the Yukon allocate more effort to reproduction than those in Colorado, but they have lower annual survival, suggesting that environmental factors can lead to life history shifts even within species. In all species, a well-developed external recruitment (rescue) capacity allows ptarmigan populations to persist in stochastic conditions for breeding and survival. The impact of climate change is expected to differ with life history. Slow life style ptarmigan populations are buffered more from climate change influences that impact fecundity but they are more vulnerable to environmental processes that decrease adult survival than the fast life style Willow Ptarmigan.

A genus at risk: Predicted current and future distribution of all three Lagopus species reveal sensitivity to climate change and efficacy of protected areas

“…Within the grouse family, the three species comprising the avian genus Lagopus, commonly known as ptarmigan, are among the most iconic of the boreal hemisphere. White-tailed ptarmigan (L. leucura), rock ptarmigan (Lagopus muta) and willow ptarmigan (L. lagopus) are cold-adapted species with Holarctic distributions, inhabiting northern tundra and/or high elevations, often as isolated glacial relict populations (Martin & Wilson, 2011;Moss et al, 2010;Storch, 2007). While genetically similar, each species exhibits notable differences in their biology, ecology and life-history strategies (Sandercock et al, 2005a(Sandercock et al, , 2005b.…”

Fine‐Scale Habitat Selection by Breeding White‐Tailed Ptarmigan in Colorado

“…Knowledge of the factors affecting habitat selection can underpin our understanding of demographic processes and reproductive effort for ptarmigan (Martin and Wilson ). Our results demonstrate habitat selection by breeding female white‐tailed ptarmigan, even with low sample sizes, is a balance between presence and availability of food resources, protective cover or thermoregulatory aid, and abiotic components.…”

“…Knowledge of the factors affecting habitat selection can underpin our understanding of demographic processes and reproductive effort for ptarmigan (Martin and Wilson 2011).…”

“…Thus, we analyzed selection at 2 local scales: patch scale (200 m 2 ; i.e., habitat patch surrounding nest and brood sites), and nest‐site scale (0.25 m 2 ; i.e., central location of nest sites). Chicks are precocial and highly mobile shortly after hatching (Martin and Wilson ). We evaluated brood habitat selection only at the patch scale, given the brood typically is scattered over a larger patch area.…”

Circumpolar status of Arctic ptarmigan: Population dynamics and trends

“…For some bird species, the impact of climate change has been explicitly studied and specific climate-related mechanisms have been revealed in the context of recent decreasing trends (Møller et al 2010;Scridel et al 2018). Although studies from different regions have pointed out how climate change likely affect future population dynamics (Sandercock et al 2005;Martin and Wilson 2011) and distribution of ptarmigan (e.g. Revermann et al 2012;Elmhagen et al 2015), we lack a good understanding of how ongoing and predicted climate change processes will affect ptarmigan populations, particularly in the Arctic (Henden et al 2017).…”