Influence of livestock soil eutrophication on floral composition in the Pyrenees mountains

Abstract

Livestock behaviour in the Pyrenees includes free grazing and a long resting period that provokes the accumulation of dung and urine in some places, so-called camping areas. The aims of this study were (i) to analyze any change in floral composition, and in nutritional and chemical contents of plants in a livestock camping area; and (ii) to relate the floral composition with soil chemical properties. In a linear transect, five sampling zones were established, from the centre of the camping area to the surrounding Nardus stricta-dominant pasture. The above ground plant biomass and the topsoil were sampled in each zone with 6 replicates per zone. Plant species were classified and weighed to calculate above ground biomass, nutritional and chemical contents, and Shannon diversity and evenness indices. Additionally, soils were sampled in two periods, at the beginning and at the end of grazing period. Soil available nutrients (nitrate, ammonium, phosphorus, potassium, calcium and magnesium), total nitrogen, organic carbon and pH were measured.Plant chemical contents (protein, lignin and others) were significantly related to the proportions of grasses, legumes and other plants; so, the protein content is positively correlated with legumes plant biomass while lignin content is negatively correlated with grasses. Both plant and soil nutrients increased linearly towards the centre of the camping area. However, the relationship among plant species richness, diversity and evenness relative to its position along the studied transect was bell-shaped. From the outskirts to the centre of the camping area, plants with low nutrient demand were progressively replaced by those with medium and high nutrients demand and by pioneers.Nardus stricta-dominant pasture has low plant diversity and plant nutrient content as well as a poor soil nutrient availability. The presence of the camping area introduced patches with more soil nutrients and new species in the large spatial scale. However at a small spatial scale, the strong soil nutrient concentration into the centre of the camping area reduced floral composition again. To ensure positive effects of camping areas on plant diversity, and to manage more effectively the nutrients returned to the soil, a reduction in the stocking rate should be pursued.

The Rengen Grassland Experiment: relationship between soil and biomass chemical properties, amount of elements applied, and their uptake

“…Results from the treatment A, the control, indicate that upper biomass production limit for Violion caninae grassland is approximately 3 t ha −1 . This is consistent with results of other authors from Violion caninae or the similar Nardus stricta grasslands (Bakker et al 2002;Hejcman et al 2007a;Badía et al 2008).…”

Productivity, grazing utilization, forage quality and primary production controls of species‐rich alpine grasslands with Nardus stricta in northern Spain

“…Mean annual fibre values (NDF and hemicellulose) were higher in wet than in mesic grassland, in accordance with similar studies on alpine swards where N. stricta was dominant (Badia et al ., ), and lower than values corresponding to Nardus plants selected from lightly grazed swards (Marinas and García‐González, ; Bovolenta et al ., ). Fibre values from the mesic grassland were closer to those of more productive and nutritive swards, such as those corresponding to the Cynosurion alliance (Badia et al ., ) or to certain plant species like Agrostis capillaris and Poa alpina (Marinas and García‐González, ; Bovolenta et al ., ). The higher proportion of forbs, with lower fibre contents than graminoids (Vázquez De Aldana et al ., ), also provides an explanation for the lower fibre content of mesic grassland with respect to wet grassland.…”

“…Crude protein values of wet grassland and their decreasing trend throughout the grazing season are consistent with patterns found in other Nardus ‐dominated grasslands (Badia et al ., ), and higher than those corresponding strictly to N. stricta (Marinas and García‐González, ; Bovolenta et al ., ). In the case of mesic grassland, CP content was 10 g kg −1 DM lower than that in wet grassland.…”

“…Values decreased throughout the grazing season, which could be mainly attributed to the increase in dead biomass. Similar forage P and K levels were found in non‐fertilized Nardion or Violion grasslands (Badia et al ., ; Hejcman et al ., ) and in N. stricta forage (Marinas and García‐González, ; Klaudisova et al ., ).…”

Are Soil Carbon Stocks in Mountain Grasslands Compromised by Land-Use Changes?

“…As a consequence, different types of vegetation develop which, in turn, influences the subsequent behaviour of the animals. Plant nutrient contents and soil nutrient availability increase from grazed to resting areas (Badia et al 2008). In highly grazed areas, in comparison with only lightly grazed ones, the availability of P increases as a consequence of cattle grazing and defecation, which may accelerate the P cycling (Güsewell et al 2005).…”