Habitat selection by breeding rock ptarmigan<i>Lagopus muta helvetica</i>males in the western Italian Alps

Nelli, Luca; Meriggi, Alberto; Franzoi, Alessandro

doi:10.2981/13-009

Cited by 9 publications

(19 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For the present work, I used the data collected in Nelli et al (2013). We conducted surveys from 20 May-20 June in 2010 and 2011 using counts of calling cocks.…”

Section: Data Collectionmentioning

confidence: 99%

“…We then measured the distance from observer to the likely position of each cock using the software QGIS. For further details, see Nelli et al (2013).…”

Section: Data Collectionmentioning

confidence: 99%

“…In Nelli et al (2013) we analyzed habitat selection by breeding rock ptarmigan males by formulating different resource selection functions with a use vs. availability approach. In particular, we used logistic regression analyses (LogRA) to compare the proportions of cover-type categories found within a 37-ha circle, the average core area of breeding rock ptarmigan males on the Alps (Favaron et al, 2006), surrounding each observed bird using three classification maps of differing information and resolution, with those measured in the random circles.…”

Section: Data Analysesmentioning

confidence: 99%

“…I chose a hexagonal grid because hexagons were the closest approximation of circles that allowed me to uniformly cover the study area. I measured the cover-type and physical variables in each cell, then I used the results of the best model obtained by Nelli et al (2013) to build a map of the potential distribution of male rock ptarmigans by applying to the area the logistic regression equation:…”

Section: Data Analysesmentioning

confidence: 99%

“…To evaluate the effect of habitat variables on density, I carried out linear models (LM) of cock density vs the habitat variables measured in a 37-ha circle around each observation point. In particular, I used the variables obtained by the forest resources map of the Piedmont Region since it was the map that allowed us to obtain the best results in Nelli et al (2013); furthermore, using QGIS I evaluated aspect by calculating average northness and eastness in the plots starting from a 25 m digital terrain model with the formulas (Zar, 1999): northness = cos(asp * π / 180) eastenss = sin(asp * π / 180) where asp is the original aspect measured in 360 degrees in the digital terrain model.…”

Section: Data Analysesmentioning

confidence: 99%

See 4 more Smart Citations

Habitat suitability models and carrying capacity estimations for rock ptarmigans in a protected area of the Italian Alps

Nelli

2015

Riv Ital Ornitol

Self Cite

View full text Add to dashboard Cite

-Rock ptarmigan populations in the Alps are suffering an overall decline, and management actions are needed to ensure their conservation. Yet wildlife management and conservation actions are often the consequences of political decisions taken by subjects that lack the scientific knowledge about the relationships between the environment and species ecology. Habitat suitability models are tools that translate these complex relationships into mathematical models and spatially explicit maps of potential presence and abundance of species that are easier to understand by people not experienced with the study of biological processes. In this study, I modelled the species-habitat relationships at two levels, by estimating the potential distribution and potential density of the species in a protected area of the Western Italian Alps. In particular, I took the results of a previous study carried out in the same area to estimate the probability of male occurrence by comparing the habitat structure in presence plots and random plots, respectively, by logistic regression analyses. Then, I applied the logistic regression equation to the same variables measured in hexagonal cells of a grid superimposed over the entire study area, and I obtained the map of the potential distribution of the species. Finally, I developed multiple regression analyses of male density estimated by distance sampling vs habitat variables, and I applied the results to the areas of potential distribution to forecast the potential density and therefore the carrying capacity of the study area. I obtained a potential distribution of 38.2 km 2 , with a potential average density of 5.1 males/km 2 . The latter was positively affected by the percentage cover of grassland and rocky grassland in the plots. The integrated approach that I used by combining models of occurrence and density allowed me to confirm and improve the results of previous works on rock ptarmigan predicted occurrence, to identify areas of conservation importance within the protected area and to give useful tools for spatially explicit management to the Natural Park administrators.Key words: Carrying capacity, Habitat suitability, Lagopus muta helvetica, Italian Alps, Potential distribution, Rock ptarmigan, Species distribution models.Riassunto -Le popolazioni italiane di pernice bianca alpina presentano uno stato di conservazione sfavorevole e appaiono in declino generalizzato su tutto l'arco alpino. Ciononostante, le azioni di gestione volte ad assicurarne la conservazione sono spesso prese in conseguenza Rivista Italiana di Ornitologia -Research in Ornithology, 85 (1): 23-30, 2015 DOI: 10.4081/rio.2015 di decisioni politiche di organi che non sono necessariamente in possesso delle nozioni sulle relazioni esistenti tra habitat ed ecologia della specie. I modelli di idoneità ambientale sono strumenti che traducono queste relazioni complesse in modelli matematici e supporti cartografici, che sono più facili da comprendere anche da chi non ha esperienza dei processi ecologici. In que...

show abstract

“…For the present work, I used the data collected in Nelli et al (2013). We conducted surveys from 20 May-20 June in 2010 and 2011 using counts of calling cocks.…”

Section: Data Collectionmentioning

confidence: 99%

“…We then measured the distance from observer to the likely position of each cock using the software QGIS. For further details, see Nelli et al (2013).…”

Section: Data Collectionmentioning

confidence: 99%

Section: Data Analysesmentioning

confidence: 99%

Section: Data Analysesmentioning

confidence: 99%

Section: Data Analysesmentioning

confidence: 99%

See 3 more Smart Citations

Habitat suitability models and carrying capacity estimations for rock ptarmigans in a protected area of the Italian Alps

Nelli

2015

Riv Ital Ornitol

Self Cite

View full text Add to dashboard Cite

show abstract

Vegetation type and demography of low density willow ptarmigan populations

et al. 2016

View full text Add to dashboard Cite

The willow ptarmigan (Lagopus lagopus) is an economically important and desired game species in Scandinavia. Its abundance varies considerably in time and space, but there has been a long-term population decline over recent decades. Earlier studies demonstrated willow ptarmigan select certain habitat features. We investigated the relationship between area-specific conditions (habitat and ownership status) and 2 variables describing willow ptarmigan demography (adult density and reproductive success). We found no connection between adult density and cover of 6 vegetation types. However, willow ptarmigan had lower reproductive success in survey areas dominated by mountain birch (Betula pubescens czerepanovii) forest. The lack of any clear association between willow ptarmigan density and vegetation types could be explained by relatively low population densities in our study areas. Thus, relative to years with higher population levels, resources (e.g., food and shelter) were plentiful and competition was low. We found strong indications in areas of similar vegetation composition that adult density was higher in areas managed by private landowners than on state-owned land. The difference in density was 2.56 birds/km 2 , equivalent to a 46% increase compared to adult density on state-owned land. This difference in density may be due to a difference in hunting pressure. We conclude that management actions to improve habitat will have little effect on willow ptarmigan populations during periods of relatively low densities. Ó

show abstract

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

et al. 2019

View full text Add to dashboard Cite

Species distributions are influenced by climate and topography in alpine ecosystems, yet resource selection studies of alpine species are uncommon. Basic characteristics of habitats used by alpine‐endemic white‐tailed ptarmigan (Lagopus leucura) have been described to explain foraging behavior, morphology, and survival in many alpine regions; however, there is a lack of information about fine‐scale habitat selection for nesting and brood‐rearing, particularly in the southern extent of the species’ range. Few studies have tested whether nest and brood‐site selection by white‐tailed ptarmigan are influenced by fine‐scale components such as vegetation and arthropod communities. We assessed these fine‐scale habitat characteristics analyzing paired use‐available resource selection for nest (n = 61) and brood (n = 54) sites. We used conditional logistic regression for data collected in 2 alpine areas along the Front Range of Colorado, USA, during 2014 and 2015. We evaluated resource selection at larger (patch) and finer (nest site) scales. Nest‐site selection at the patch scale was best predicted by cover (%) of forage forbs, rock and gravel, and shrubs. Forage forb cover explained more variation in our top nest model at the patch scale when compared to models with specific vegetation species. Females placed their nests along elevational gradients but more so at lower elevations and selected for less graminoid cover at the nest‐site scale. Brood habitat selection at the patch level was influenced by cover (%) of rock and gravel and proximity to shrubs (m). Analysis of a subset of our brood data (n = 34) revealed females selected brood habitat that contained high arthropod abundance (e.g., Cicadellidae) over high vegetation cover, likely as a response to meet dietary requirements of chicks. Our results demonstrate how and where white‐tailed ptarmigan are currently selecting these different breeding sites in Colorado's alpine, giving us insight into consequences this alpine‐endemic bird may face if their breeding habitat is altered. © 2019 The Wildlife Society.

show abstract

Habitat selection by breeding rock ptarmiganLagopus muta helveticamales in the western Italian Alps

Cited by 9 publications

References 21 publications

Habitat suitability models and carrying capacity estimations for rock ptarmigans in a protected area of the Italian Alps

Habitat suitability models and carrying capacity estimations for rock ptarmigans in a protected area of the Italian Alps

Vegetation type and demography of low density willow ptarmigan populations

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

Contact Info

Product

Resources

About