Response of forage nutrient storages to grazing in alpine grasslands

Abstract

Forage nutrient storages can determine livestock size and husbandry development. There is insufficient research on the response of forage nutrient storages to grazing and related driving mechanisms in alpine grasslands, especially on the Tibetan Plateau. This study conducted a grazing experiment in three alpine grassland sites along an elevation gradient (two warm-season pastures and one cold-season pasture; two alpine steppe meadow sites and one alpine meadow) of Northern Tibet. Different types of alpine grassland ecosystems, at least for forage nutrient storages, may have different responses to grazing. Warm-season grazing significantly reduced crude protein (CP) storage, acid detergent fiber (ADF) storage, and neutral detergent fiber (NDF) storage of high-quality forage by 53.29, 63.82, and 63.26%, respectively, but cold-season grazing did not significantly alter the CP, ADF and NDF storages of high-quality forage. Warm-season grazing significantly reduced CP, ADF, NDF, crude ash (Ash), ether extract (EE) and water-soluble carbohydrate (WSC) storages of the plant community by 46.61, 62.47, 55.96, 64.94, 60.34, and 52.68%, and forbs by 62.33, 77.50, 73.69, 65.05, 57.75, and 62.44% in the alpine meadow site but not the alpine steppe meadow site, respectively. Plant species and phylogenetic diversity had different relationships with forage nutrient storages. The elevation distribution of forage nutrient storages under fencing conditions were different from those under grazing conditions. Therefore, cold-season grazing can have lower negative effects on forage nutrient storages than warm-season grazing. Combined plant species with phylogenetic diversity and composition can be better in predicting forage nutrient storages. Grazing can restructure the elevation distribution of forage nutrient storages in alpine grasslands.

Quantifying Plant Species α-Diversity Using Normalized Difference Vegetation Index and Climate Data in Alpine Grasslands

“…However, some earlier studies have proved that radiation change had stronger influences on nutrition quality of plant community than temperature change and precipitation change in alpine grassland ecosystems of Tibet [20,27]. Meanwhile, plant species α-diversity can be closely correlated with nutrition quality and nutrition production of plant community in alpine grassland ecosystems of Tibet [8,30]. Moreover, plant growth is indeed influenced by radiation, although photoinhibition may occur under relatively higher magnitude radiation in alpine regions of the Qinghai-Tibet Plateau [31][32][33].…”

“…Quantitative plant species α-diversity of grasslands at multiple spatial and temporal scales, as one key aspect of plant diversityrelated studies, is important for assessing the responses of biodiversity to global change and protecting biodiversity under global change [5][6][7]. Although there are numerous studies which are related to plant diversity [8][9][10][11][12], some issues are still not resolved. Firstly, on the one hand, with the increasing number of responsibilities in the work of scientists, there are fewer experienced researchers with sufficient knowledge in diagnostics who can supplement the tests performed in the small area system.…”

“…Actually, several earlier studies have been carried out on the plant α-diversity of alpine grassland ecosystems in Tibet [8,9,11,12,28,29]. These earlier studies can have important guiding significance for the conservation of biodiversity in alpine grassland ecosystems of Tibet and even the world.…”

Non-growing/growing season non-uniform-warming increases precipitation use efficiency but reduces its temporal stability in an alpine meadow

“…2 Materials and methods 2.1 Survey area, experiment design, data observation/simulation and the calculation of PUE and PUE stability Earlier studies fully described the survey area, experiment design, measures/simulations of soil temperature (T s ), air temperature (T a ), soil moisture (SM), vapor pressure deficit (VPD), normalized difference vegetation index (NDVI), aboveground biomass (AGB), end of growing-season (EGS), start of growing-season (SGS) and growing-season length (GSL) (Fu et al, 2019;Fu and Shen, 2022). The survey area was illustrated in Figure S1 and located in an alpine meadow of the Northern Tibet (Fu and Sun, 2022;Zha et al, 2022). Mean annual precipitation (MAP) was about 476.36 ± 96.69 mm and mean annual temperature (MAT) was about 1.96 ± 0.80 °C in 1963-2019 (Fu and Shen, 2022).…”

Asymmetric warming among elevations may homogenize plant α-diversity and aboveground net primary production of alpine grasslands

“…Grasslands, as an important vegetation type in global ecosystems, are key resources for high-quality development of livestock industry and an important place for wildlife protection Zha et al, 2022;Han et al, 2022a;Wang and Fu, 2023). Alpine grasslands are important sections of global grasslands, and may be the most sensitive and fragile grassland types to global change (Zhang et al, 2015(Zhang et al, , 2022Fu and Sun, 2022).…”