Main ecological and environmental factors affecting forage yield and quality in alpine summer pastures (NW‐Italy, Gran Paradiso National Park)

Abstract

Summer pastures in the European Alps play a crucial role in providing high quality forage for grazing livestock and encompass a wide variety of vegetation communities. The main issue of their management is the optimal exploitation of the available forage in relation to environmental constraints, aiming at obtaining the highest forage yield and quality from each vegetation community. In this work, we monitored six different vegetation communities characterized by contrasting topographic features and species compositions throughout the grazing season for two years. We performed botanical and phenological surveys, climate‐related measurements, and herbage samplings to assess forage quantity and quality (i.e., digestibility and proximate composition, estimated by near‐infrared reflectance spectroscopy). We analysed the influence of climatic, topographic, and vegetation variables on pasture herbage through univariate and multivariate analyses. The cover of wide‐leaf grasses primarily promoted biomass production, which was in turn lowered by increasing elevation and slope. On the other hand, a minor effect on forage yield was observed for an increasing cover of sedges and rushes and mean temperatures. Climatic variables (especially water deficit) and advanced phenological stages were the main degrading factors of forage quality in terms of crude protein and digestibility, while enhancing fibre contents. At increasing cover of legumes, fibre content declined and digestibility increased consequently, while the abundance of other non‐legume forbs played a significant role in lowering fibre content. Multivariate analysis highlighted the differing influence of single plant species on forage features even within the same functional species pool. However, attention should be paid to the toxicity and low palatability of some plants, especially forbs. Eutrophic vegetation communities, rich in wide‐leaf grasses and legumes, could be maintained and enhanced through pastoral management to increase alpine pasture production and quality.

Shrinking Alpine chamois: higher spring temperatures over the last 27 years in Switzerland are linked to a 3 kg reduction in body mass of yearlings

“…The lack of resources for mothers during the lactation period might influence how much energy can be allocated to nursing, with cascading effects on offspring growth. Second, although climate warming can increase plant productivity, Alpine plants are sensitive to heat stress and droughts, and climate warming is expected to decrease forage quality and palatability in Alpine grassland systems [ 8 , 9 ] for nursing mothers and their offspring. Third, ambient temperatures can also strongly influence the nutrient intake of yearling chamois during growth by altering the feeding activity [ 22 ] in young and adults.…”

“…Our results support previous studies showing the importance of climatic conditions for ungulate growth at high elevations and latitudes [ 17 , 19 , 23 ]. Although ungulates can modify their behaviours by eating at night [ 49 ] or shifting their range to higher elevations [ 7 ] to cope with warming spring and summer temperatures, these changes in behaviour cannot cope with the negative effects of climatic conditions on forage quality and palatability [ 8 , 9 ], which persist throughout the day and can be observed at a wide range of elevation. Hence, studies on the effects of climate warming on the quantity and quality of forage during the time window most sensitive for ungulate growths (e.g.…”

“…Global warming is also likely to impact body size due to changes in food availability and quality [7]. For example, the increase in frequency and length of summer droughts is expected to reduce forage quality and palatability for grazing species [8][9][10]. In mammals, high ambient temperature, together with the limits to the ability to dissipate heat, has also been previously shown to constrain maternal milk production and offspring growth [5,11], limiting adult size.…”

Seminatural Grasslands: An Emblematic Challenge for Nature Conservation in Protected Areas

“…The chemical attributes of pastures and mowed/grazed meadows have rarely been analysed in combination with both PV and floristic-vegetation traits, mainly in the alpine context [155,156]. More often, forage yield and quality have been evaluated through proxies [157][158][159].…”

Gridded livestock density database and spatial trends for Kazakhstan

“…Elevated precipitation levels increase above-ground biomass, enabling herders to maintain more livestock at these productive sites, where forage consumption is higher 84 . Furthermore, few studies have shown high grassland carrying capacities during summer, owing to the high foraging value in relatively warm and humid conditions 81 , 85 . The strong relationship between livestock, human population density and proximity to settlements reflects (i) the huge demand for meat in the rural-urban continuum, (ii) the need for people and infrastructure to raise livestock, and (iii) the importance of KZ as an exportation hub 2 , 32 , 75 , 86 .…”