Spatial distribution and settlement strategies in willow ptarmigan

Kvasnes, Mikkel Andreas Jørnsøn; Pedersen, Hans Chr.; Solvang, Håkon; Storaas, Torstein; Nilsen, Erlend B.

doi:10.1007/s10144-014-0454-1

Cited by 9 publications

(17 citation statements)

References 75 publications

(121 reference statements)

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“…Moreover, reduced carrying capacity induced by habitat loss will not necessarily reduce per capita reproductive output directly, so much that it forces adults to vacate poorer areas in favor of more suitable habitat. Something similar has been observed in willow ptarmigan (Lagopus lagopus), in which reproduction seems to be spatially independent (Hörnell-Willebrand et al, 2006;Kvasnes et al, 2014).…”

Section: Intensified Land-usementioning

confidence: 65%

Declining reproductive output in capercaillie and black grouse – 16 countries and 80 years

Jahren¹,

Storaas²,

Willebrand³

et al. 2016

Animal Biol

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Declines in populations of capercaillie (Tetrao urogallus) and black grouse (Lyrurus tetrix) have been reported from both Central Europe and the continuous boreal forests of Fennoscandia. While intensified land-use is assumed to be the underlying cause of these declines, the mechanisms are not yet understood. Predation is the proximate cause of mortality of eggs, chicks and adults throughout capercaillie and black grouse ranges, but the link between predation and habitat and/or climate change remains unclear. To investigate temporal trends in reproductive output of woodland grouse, we collated previously published and unpublished data of reproduction in capercaillie and black grouse throughout their ranges from 1930 to 2012. We show that, overall, reproductive success has decreased and stabilized at low levels in most regions whilst capercaillie reproductive output in Scotland is still declining. With today's net reproduction, capercaillie and black grouse adult survival is too low to compensate for reproduction declines. Consequently, populations are expected to further decline unless reproductive performances improve. We put our findings in the context of changes in land use, climate and generalist predator numbers. By critically reviewing how these factors limit reproductive success in capercaillie and black grouse, we hope to shed light on the underlying mechanisms causing the decline. Our results imply that measures should be undertaken to reduce mortality of capercaillie and black grouse chicks and eggs. We suggest that future studies should aim to better understand which predators limit capercaillie and black grouse populations and how predation rates are mediated by continuously changing habitat and climate.

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Section: Intensified Land-usementioning

confidence: 65%

Declining reproductive output in capercaillie and black grouse – 16 countries and 80 years

Jahren¹,

Storaas²,

Willebrand³

et al. 2016

Animal Biol

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“…The main idea is to establish a source-sink dynamic (Pulliam, 1988) between harvested and non-harvested areas (see e.g., Novaro et al, 2005). So far, the effect of refuges on ptarmigan population dynamics remains unclear because of uncertainty related to the spatial distribution and settlement strategies (Kvasnes et al, 2015). Besides from addressing hunting effort, regulations aiming to reduce the hunting efficiency may also be implemented.…”

Section: Limiting Total Hunting Effort or Efficiencymentioning

confidence: 99%

Harvest Regulations and Implementation Uncertainty in Small Game Harvest Management

2017

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A main challenge in harvest management is to set policies that maximize the probability that management goals are met. While the management cycle includes multiple sources of uncertainty, only some of these has received considerable attention. Currently, there is a large gap in our knowledge about implemention of harvest regulations, and to which extent indirect control methods such as harvest regulations are actually able to regulate harvest in accordance with intended management objectives. In this perspective article, we first summarize and discuss hunting regulations currently used in management of grouse species (Tetraonidae) in Europe and North America. Management models suggested for grouse are most often based on proportional harvest or threshold harvest principles. These models are all built on theoretical principles for sustainable harvesting, and provide in the end an estimate on a total allowable catch. However, implementation uncertainty is rarely examined in empirical or theoretical harvest studies, and few general findings have been reported. Nevertheless, circumstantial evidence suggest that many of the most popular regulations are acting depensatory so that harvest bag sizes is more limited in years (or areas) where game density is high, contrary to general recommendations. A better understanding of the implementation uncertainty related to harvest regulations is crucial in order to establish sustainable management systems. We suggest that scenario tools like Management System Evaluation (MSE) should be more frequently used to examine robustness of currently applied harvest regulations to such implementation uncertainty until more empirical evidence is available.

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“…The Willow Ptarmigan (Lagopus lagopus) is a medium-sized grouse distributed in alpine tundra habitats in the northern hemisphere (Johnsgard 1983). They have a short generation time (T = 1.8, Sandercock et al 2005 andannual mortality[46 %, Sandercock et al 2011;Smith and Willebrand 1999) and each female may produce up to 12 chicks annually, although recruitment of juveniles as well as densities of breeding birds vary both in time and space (Johnsgard 1983;Kvasnes et al 2013). Several studies have documented that weather conditions during the breeding season can influence recruitment rates in ptarmigan (Hannon and Martin 2006;Novoa et al 2008;Slagsvold 1975;Martin and Wiebe 2004;Steen et al 1988a, b).…”

Section: Introductionmentioning

confidence: 99%

Large-scale climate variability and rodent abundance modulates recruitment rates in Willow Ptarmigan (Lagopus lagopus)

Kvasnes¹,

Pedersen

Storaas³

et al. 2014

J Ornithol

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Recruitment of juveniles is important for the size of the next year's breeding population in many bird species. Climate variability and predation may affect recruitment rates, and when these factors are spatially correlated, recruitment rates in spatially separated populations of a species may be synchronized. We used production data from an extensive survey of Willow Ptarmigan from 2000 to 2011 to investigate spatial synchrony in recruitment of juveniles within and among mountain region populations. In addition, we assessed the effects of predation and large-as well as local-scale climate on recruitment of juveniles. Recruitment was synchronized both within and among mountain regions, but the mean spatial correlation was strongest among mountain regions. This may be caused by small-scale factors such as predation or habitat structure, or be a result of sampling variation, which may be large at small spatial scales. The strong synchrony suggests that populations are subject to similar environmental forces. We used mixed effect models at the survey area and mountain region scales to assess the effect of rodent abundance (a proxy for predation rates) and local and regional climate during the breeding season on the recruitment of juvenile birds. Model selection based on AICc revealed that the most parsimonious models at both spatial scales included positive effects of rodent abundance and the North Atlantic oscillation during May, June and July (NAO MJJ ). The NAO MJJ index was positively related to temperature and precipitation during the pre-incubation period; temperature during the incubation period and positive NAO MJJ values accelerate plant growth. A comparison of the relative effects of NAO MJJ and rodent abundance showed that variation in NAO MJJ had greatest impact on the recruitment of juveniles. This suggests that the climate effect was stronger than the effect of rodent abundance in our study populations. This is in contrast to previous studies on Willow Ptarmigan, but may be explained by the collapse in rodent cycles since the 1990s. If Willow Ptarmigan dynamics in the past were linked to the rodent cycle through a shared predator regime, this link may have been weakened when rodent cycles became more irregular, resulting in a more pronounced effect of environmental perturbation on the dynamics of ptarmigan.

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Spatial distribution and settlement strategies in willow ptarmigan

Cited by 9 publications

References 75 publications

Declining reproductive output in capercaillie and black grouse – 16 countries and 80 years

Declining reproductive output in capercaillie and black grouse – 16 countries and 80 years

Harvest Regulations and Implementation Uncertainty in Small Game Harvest Management

Large-scale climate variability and rodent abundance modulates recruitment rates in Willow Ptarmigan (Lagopus lagopus)

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