The effect of tree cover on the biomass and diversity of the herbaceous layer in a Mediterranean dehesa

Abstract

Mediterranean dehesas are an archetypal example of high nature value farmland in Europe. To better understand the interactions between trees and grasslands in the conservation and management of the dehesa, we measured, over 3 years, the contribution of scattered trees to the diversity and biomass dry-matter (DM) yield of the herb layer and the relationship between the herb layer (biomass and diversity interaction) and the trees. The study was based on 135 subplots representing four aspects and three distances from fifteen trees selected randomly in a plot within a dehesa in central Spain. The specific questions were the following: (i) To what extent do trees affect biomass of the herbaceous layer? (ii) What is the relationship between herbaceous layer biomass and species diversity under the influence of trees? and (iii) What are the effects of trees and small-scale topography on the herbaceous diversity? Results differed between years depending on water availability. Legume and forb DM yields were highest at the edge of the tree crown and beyond the canopy. Species richness was positively related to legume DM yield, and both were higher at the bottom of the hillside, especially in dry conditions. Given the importance of tree influence on the biomass and diversity of grasslands, maintaining proper agroforestry management practices for trees and grasslands is important for conserving dehesa diversity and productivity under the conditions of high climatic and soil variability in Mediterranean dehesas.

N : P stoichiometry and habitat effects on Mediterranean savanna seasonal root dynamics

“…This was driven by a high root biomass, peaking at around 8000 kg ha −1 despite being calculated based on only the top 13 cm. Other studies in similar landscapes in southwestern Europe found maximum root masses of around 2000 kg ha −1 (dependent on cover type; Rolo and Moreno, 2012), 2500 kg ha −1 (Jongen et al, 2013) or under 300-400 kg ha −1 in nearby walnut forestry (López-Díaz et al, 2017), where pasture production was around 2 times higher than our site (Gerardo Moreno, personal communication, 2018). Despite sampling soil profiles to deeper depths, root : shoot ratios at these sites were considerably lower than ours (e.g.…”

“…The same difference in roots between habitat type was not found from minirhizotrons, where we consistently observed greater RLD in open pasture throughout the year. Between tree-covered and pasture areas of dehesas there are major differences in herbaceous layer diversity (López-Carrasco et al, 2015) and community vegetation composition (Marañon, 1986), which affects plant trait distributions. RLD and specific root length are important below-ground plant traits linked to plants' ability to explore soil and acquire Normalized difference vegetation index (NDVI) and grassland green chromatic coordinate (GCC).…”

“…high specific root length; Hodge, 2004) and capable of high nutrient uptake. Interestingly, tree cover tends to promote more (relatively high RLD) graminoids over legumes and forbs in dehesas (López-Carrasco et al, 2015), and N abundance (comparatively higher under canopies in dehesa systems; Gallardo (2003)) tends to shift community composition towards grasses (Bobbink et al, 2010). However, in heterogeneous environments, high RLD may provide competitive advantages, even if high-RLD individuals are less focused on particular nutrient hotspots (Mommer et al, 2011).…”

Productivity and nutritive value of Brachiaria decumbens and performance of dairy heifers in a long‐term silvopastoral system

“…() have suggested that an option for sustainable livestock production is the adoption of silvopastoral system (SPS). Among the productive and environmental benefits of the SPS, the following stand out: Improved soil nutrient availability, increased animal production associated with thermal comfort, and higher crude protein (CP) content of forage, as well as the possibility of income diversification in the property (Baliscei et al., ; Kyriazopoulos, Abraham, Parissi, Koukoura, & Nastis, ; Murgueitio, Calle, Uribe, Calle, & Solorio, ; Paciullo et al., ), and environmental services, such as increased biodiversity, sequestration of atmospheric carbon and mitigation of greenhouse gases (Alves, Madari, & Boddey, ; López‐Carrasco, López‐Sánchez, San Miguel, & Roig, ).…”

Aspectos aplicados de la ecología de la tórtola común (Streptopelia Turtur L.) en un ambiente forestal mediterráneo

“…Forest grasslands can be, therefore, important foraging habitats for Turtle Doves. Differently to farmland areas, where weed seeds are directly limited by agricultural practices, factors as scattered tree presence, grazing and annual rainfall are the main drivers of herbaceous community characteristics in forest areas , López-Carrasco et al 2015, López-Sánchez et al 2016. The abundance of weed species whose seeds are consumed by Turtle Dove in this type of habitats vary depending on grazing management (Tarrega et al 2009, López-Sánchez et al 2016.…”