Grazing effects on plant functional group diversity in Mediterranean shrublands

Abstract

Grazing is one of the prevalent human activities that even today are taking place inside protected areas with direct or indirect effects on ecosystems. In this study we analyzed the effects of grazing on plant species diversity, plant functional group (PFG) diversity and community composition of shrublands. We analyzed plant diversity data from 582 sampling plots located in 66 protected areas of the Greek Natura 2000 network, containing in total 1102 plant species and subspecies. We also classified a priori all plant species in seven PFGs: annual forbs, annual grasses/sedges, legumes, perennial forbs, perennial grasses/sedges, small shrubs and tall shrubs. For each site, grazing intensity was estimated in four classes (no grazing, low, medium and high grazing intensity). We found that, at the spatial and temporal scale of this study, as grazing intensity increased, so did total species richness. However, each PFG displayed a different response to grazing. Shortlived species (annual grasses or forbs and legumes) benefited from grazing and their species richness and proportion in the community increased with grazing. Perennial grasses and forbs species richness increased with grazing intensity, but their dominance decreased, since their proportion in the community declined. Short shrub species richness remained unaffected by grazing, while tall shrub diversity decreased. Finally, in sites without grazing the spatial pattern of species richness of the different PFGs was not congruent with each other, while in grazed sites they were significantly positively correlated (with the exception of tall shrubs). This finding may imply that grazing is a selective pressure organizing the community structure, and imposing a certain contribution of each PFG. So, in Mediterranean shrublands in protected areas with a long historical record of grazing, it seems that grazing promotes species diversity and its continuation on a portion of the landscape may be a necessary part of an effective management plan.

Gaps in ecological research on the world's largest internationally coordinated network of protected areas: A review of Natura 2000

“…EEA's's (2015b) "State of nature in the EU" reports that farmland bird populations continue to decline. On one hand, some traditional agricultural activities, such as grazing and mowing, may be essential for maintaining and restoring some habitats and associated species and thus should be incorporated into management plans of N2k sites (Halada et al, 2011;Papanikolaou et al, 2011;Faria et al, 2012;Arponen et al, 2013). On the other hand, some practices such as intensification of cultivation or use of pesticides may pose threats to biodiversity in the conservation network (EEA, 2015b).…”

Fuzzy Index and Self-Organizing Feature Map Index for Measuring Functional Diversity Applied to Acanthopanax Senticosus Communities

“…This suggested that functional diversity and species richness were interrelated with each other [25,28]. Each species should have some special functional traits, therefore the greater the number of species in a community is, the greater the change of functional traits and the greater the functional diversity are [6].…”

“…which affect plant and community growth and development [15,23]. The effects of aspect and litter thickness on functional diversity were not significant because Acanthopanax senticosus lived in forest under canopy where litters and aspect were consistent [11,28].…”

Populations of two annual clover species evolved in response to 13 years of grazing management and phosphate fertilizer application

“…Phosphate application, favouring the relative competitive plants, was associated with increased between-year seed dormancy. In a meta-study of 582 plots across Greece, Papanikolaou et al, (2011) found short-lived species (including annual legumes) benefited from grazing and proportion in the community increased with grazing. Pierce, Luzzaro, Caccianiga, Ceriani, and Cerabolini (2007) found that grazing suppresses potentially dominant species and favours diversity.…”