Community Seasonal Development Enables Late Defoliation Without Loss of Forage Quality in Semi-natural Grasslands

Abstract

Agri-environmental measures often require postponing of grassland defoliation until summer months. We investigated how this affects agronomic characteristics, i.e., biomass production and forage quality, in species-rich grasslands in the White Carpathian Mountains, Czech Republic. Three distinct grasslands (vegetation alliances Bromion erecti, Cynosurion cristati, Violion caninae) were selected for biomass sampling in three dates: mid-May, early June and end of June. Proportions of individual species from total biomass, biomass production, crude fibre concentration, organic matter digestibility and community functional properties (forage value, leaf dry matter content, specific leaf area) were determined. Dry matter standing biomass at the end of June was highest in Bromion with 3.5 t/ha, followed by Violion with 2.7 t/ha and Cynosurion with 2.3 t/ha. A steep decline in forage quality (increase in crude fibre and decrease in organic matter digestibility) during accumulation of aboveground biomass was recorded in formerly unmanaged Bromion grassland but remarkably not in formerly grazed Cynosurion and Violion grasslands where early spring dominants were partly replaced by later developing species, Agrostis capillaris and Trifolium spp. Abundance-weighted community functional properties were consistent with results obtained from biomass chemical analyses, thus the 'trait approach' can be used as a suitable surrogate of costly and labor-intensive laboratory procedures. Finally, we assume that the high degree of community seasonal development in Cynosurion and Violion, indicated here by a new community seasonal development index and by development in community specific leaf area, was accountable for the stabilization of forage quality later in the vegetation season.

Effects of grazing on seasonal variation of aboveground biomass quality in calcareous grasslands

“…For all nutrients, we found a significant decline from April to July. Decreasing nutrient concentrations during the growing season are a well-known phenomenon and could be traced back to ongoing senescence of plant tissues, changes in the leaf:stem ratio, nutrient allocation to roots and losses of, e.g., nutrient-rich seed biomass (Bobbink et al 1989;Marschner 2005;Hejcman et al 2010b;Mládek et al 2011). Reduced growth of young nutrient-rich plant tissues because of summer drought may also be a relevant factor (Kahlert et al 2005).…”

“…Management aspects were mostly discussed from the viewpoint of nature conservation (Willems 2001;Kahmen et al 2002;Wallis De Vries et al 2002;Römermann et al 2009). In contrast, profound information for managers of non-intensively used grasslands with respect to biomass quality and its seasonal variation in relation to grazing is scarce Mládek et al 2011). However, exactly this knowledge and in particular a greater understanding of the mechanisms by which plants are responding to grazing is needed to develop management strategies that meet both agronomic and biodiversity targets (Bullock et al 2001).…”

Ecological-agricultural perspective on the quality of pasture vegetation

“…Rich grasslands with a high proportion of forbs do not lose nitrogen and mineral substances or digestibility after the blooming phase as quickly as sown grass-clover mixtures, and it is also possible to postpone the harvest by several weeks, if necessary (Mládek, et al, 2011;Jendrišáková, et al, 2011). These grasslands can therefore be managed with a lower intensity, which supports the species diversity of forbs as well as other related groups of organisms, mainly invertebrates (Šarapatka and Niggli, 2008).…”

Habitat use at fine spatial scale: how does patch clustering criteria explain the use of meadows by red deer?

“…Most of the sampled CYN patches were within currently managed meadows, which, due to irrigation, have relatively constant soil moisture and consequently an extended vegetative season, both during summer and winter. Additionally, these communities are periodically grazed and manured by domestic cattle, generating high nutritive grazing lawns (Mládek et al 2011): floristic composition comprises species such as the high-quality grasses Cynosurus cristatus, Holcus lanatus or Anthoxanthum odoratum, forbs like Plantago lanceolata, Sanguisorba minor, and legumes such Trifolium spp. that are very palatable for deer (Arsenault and Owen-Smith 2002;Gordon 1988;Vavra 2005), and thus would be expected to be preferred by deer.…”