Estimation of the chemical composition of black grouse <i>Tetrao tetrix</i> diets in the eastern Italian Alps

Filacorda, Stefano; Sepulcri, Angela; Piasentier, Edi; Franceschi, Paolo F. de

doi:10.2981/wlb.1997.023

Cited by 5 publications

(4 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…observing foraging individuals, analysing the craw or stomach content or analysing intestinal faecal pellets (droppings) (Bertermann et al 1998;Filacorda et al 1997;Kuc 1964;Zbinden 1984). However, all three approaches hold several advantages and disadvantages: Direct observations of (tagged) foraging birds are very costly in terms of time, taking at least 1 year to cover the whole spectrum of feeding plants and plant parts when addressing their seasonally changing availability (Keller et al 1979;Bertermann et al 1998).…”

Section: Introductionmentioning

confidence: 99%

Analyses of Black Grouse (Tetrao tetrix) faeces with infrared spectroscopic methods

2015

View full text Add to dashboard Cite

In recent years, the Fourier transform infrared spectroscopy (FT-IR) was used to assess the diet, digestibility or nutritional values of food items of ruminants. However, it has never been used to analyse the diet of grouse species. Commonly used methods have so far been direct observations of birds and microscopical analyses of droppings. The sample preparation and comparison of microscopical analyses is a highly time-consuming procedure. The comparison is based on morphological structures of epidermal cells, like the shape of cells, stomata or trichomes. In contrast, the sample preparation for the FT-IR and the subsequent measuring is simple and quickly done. We investigated the diet of Black Grouse (Tetrao tetrix L.) in two study areas with infrared spectroscopic methods comparing summer and winter droppings' content with plant reference material. The study areas are located in the provinces of Salzburg and Upper Austria, Austria. In our study, samples were measured in the mid-and nearinfrared range. We tried to determine the dominating content of faecal samples at species, genera or family level or at least to assign samples to one of four main plants groups (i.e. woody plants, heathers, herbs and grasses). Our results showed a dominance of Larix decidua within the group of woody plants in both areas and, within the group of heathers, a dominance of Calluna vulgaris and Rhododendron hirsutum in one study area. Partially, our results are in marked contrast to other studies conducted in the Alps, as Vaccinium myrtillus was not detected in the samples. For further methodological studies, faecal sampling over larger areas, larger samples of plant reference material (including seeds and other parts of plants at different seasons), taking more samples per dropping and synchronous comparisons of microscopic analyses as well as FT-IR spectroscopy, are recommended.

show abstract

Section: Introductionmentioning

confidence: 99%

Analyses of Black Grouse (Tetrao tetrix) faeces with infrared spectroscopic methods

2015

View full text Add to dashboard Cite

show abstract

“…The most abundant species in 2002 and 2003 was Rh . ferrugineum , with Calluna vulgaris also prevalent in 2004, both species of low nutritional value [ 56 ]. When snow melts, plants and invertebrates that provide food to ptarmigan during the reproductive period begin to grow and several studies have pointed to a close relationship between the timing of snowmelt and reproductive success [ 4 , 25 , 57 , 58 ].…”

Section: Discussionmentioning

confidence: 99%

Factors Affecting Diet Variation in the Pyrenean Rock Ptarmigan (Lagopus muta pyrenaica): Conservation Implications

García‐González

Aldezábal²,

Laskurain³

et al. 2016

PLoS ONE

View full text Add to dashboard Cite

The Pyrenean rock ptarmigan (Lagopus muta pyrenaica) lives at one of the southernmost limits of the ptarmigan range. Their small population sizes and the impacts of global changes are limiting factors in the conservation of this threatened subspecies. An effective conservation policy requires precise basic knowledge of a species' food and habitat requirements, information that is practically non-existent for this Pyrenean population. Here, we describe the diet of a ptarmigan population in the Eastern Pyrenees, the environmental factors influencing its variability and the relationship between diet floristic composition and quality. Diet composition was determined by microhistological analysis of faeces and diet quality was estimated from free-urate faecal N content. Our results show that grouse diet is based mainly on arctic-alpine shrubs of the Ericaceae family, as well as dwarf willows (Salix spp.) and Dryas octopetala. The most frequently consumed plant species was Rhododendron ferrugineum, but its abundance in the diet was negatively related to the diet nitrogen content. Conversely, the abundance of Salix spp., grass leaves and arthropods increased the nitrogen content of the diet. Seasonality associated with snow-melting contributed the most to variability in the Pyrenean ptarmigan diet, differentiating winter from spring/summer diets. The latter was characterised by a high consumption of dwarf willows, flowers, arthropods and tender forb leaves. Geographic area and sex-age class influenced diet variability to a lesser extent. Current temperature increases in the Pyrenees due to global warming may reduce the persistence and surface area of snow-packs where preferred plants for rock ptarmigan usually grow, thus reducing food availability. The high consumption of Rh. ferrugineum characterised the diet of the Pyrenean population. Given the toxicity of this plant for most herbivores, its potential negative effect on Pyrenean ptarmigan populations should be evaluated.

show abstract

“…Potential N content of each individual diet was estimated from the abundance of each food item in faecal samples (microhistological analysis) multiplied by their N content following the expression, N d = ΣX i *N x where N d is the potential N content of a faecal sample, X i the proportion of food item i in the faecal sample and N x the N content (% of dry matter) of the food item X in the respective month or time period (see S1 Table ). Nutritive content estimation of mixed or composite diets from the food nutrient content and the proportion of each food item is a common procedure in herbivorous birds [ 9 , 47 , 48 ]. Potential N content of faecal samples were calculated by month during the breeding season, and for the whole winter period.…”

Section: Methodsmentioning

confidence: 99%

Influence of Snowmelt Timing on the Diet Quality of Pyrenean Rock Ptarmigan (Lagopus muta pyrenaica): Implications for Reproductive Success

García‐González

Aldezábal²,

Laskurain³

et al. 2016

PLoS ONE

View full text Add to dashboard Cite

The Pyrenean rock ptarmigan (Lagopus muta pyrenaica) is the southernmost subspecies of the species in Europe and is considered threatened as a consequence of changes in landscape, human pressure, climate change, and low genetic diversity. Previous studies have shown a relationship between the date of snowmelt and reproductive success in the Pyrenean ptarmigan. It is well established that birds laying early in the breeding season have higher reproductive success, but the specific mechanism for this relationship is debated. We present an explicative model of the relationship between snowmelt date and breeding success mediated by food quality for grouse in alpine environments. From microhistological analyses of 121 faecal samples collected during three years in the Canigou Massif (Eastern Pyrenees), and the assessment of the chemical composition of the main dietary components, we estimated the potential quality of individual diets. Potential dietary quality was correlated with free-urate faecal N, a proxy of the digestible protein content ingested by ptarmigan, and both were correlated with phenological stage of consumed plants, which in turn depends on snowmelt date. Our findings suggest that the average snowmelt date is subject to a strong interannual variability influencing laying date. In years of early snowmelt, hens benefit from a longer period of high quality food resources potentially leading to a higher breeding success. On the contrary, in years of late snowmelt, hens begin their breeding period in poorer nutrient condition because the peaks of protein content of their main food items are delayed with respect to laying date, hence reducing breeding performance. We discuss the possible mismatch between breeding and snowmelt timing.

show abstract

Estimation of the chemical composition of black grouse Tetrao tetrix diets in the eastern Italian Alps

Abstract: BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access titles in the biological, ecological, and environmental sciences published by nonprofit societies, associations, museums, institutions, and presses.

Cited by 5 publications

References 8 publications

Analyses of Black Grouse (Tetrao tetrix) faeces with infrared spectroscopic methods

Analyses of Black Grouse (Tetrao tetrix) faeces with infrared spectroscopic methods

Factors Affecting Diet Variation in the Pyrenean Rock Ptarmigan (Lagopus muta pyrenaica): Conservation Implications

Influence of Snowmelt Timing on the Diet Quality of Pyrenean Rock Ptarmigan (Lagopus muta pyrenaica): Implications for Reproductive Success

Contact Info

Product

Resources

About