Plant Diversity in Sardinian Mountain Rangelands: Analysis of Its Relationships with Grazing, Land Management, and Pastoral Value

Vanessa Lozano,Gabriella Vacca,Federico Sanna,Giovanni Antonio Re,Ignazio Camarda,Salvatore Caredda,Giuseppe Brundu

doi:10.3390/ecologies2010009

Vanessa Lozano, Gabriella Vacca + Show 5 more

Open Access

https://doi.org/10.3390/ecologies2010009

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Abstract

In this study, we analyzed the effects of grazing on native and endemic plant diversity, as well as its relationship with pastoral value along a gradient of abiotic and biotic factors and types of land management in a mountainous area of central-eastern Sardinia, Italy. Plant diversity was estimated by conducting a floristic survey within plots. In total, 231 plant species were recorded in 63 plots distributed within the study area, and this total number included 20 endemic species. Species richness was mainly affected by the type of management, soil attributes, altitude, and bioclimate. Pastoral value was strongly affected by nutrient availability and bioclimate. Our results suggest that the cover of endemic species increases with altitude. Finally, in Sardinian rangelands, a negative effect of grazing pressure on endemic species was observed.

Highlights

Rangelands cover approximately one-third of the Earth’s land area and at least one billion people depend on these lands to live, both directly through livestock production and indirectly from other resources and ecosystem services [1,2]
We observed with significant high frequencies the following endemic species: Armeria sardoa Spreng., Astragalus genargenteus Moris, Genista morisii Colla, Pancratium illyricum L., Plantago sarda C.Presl, and Ptilostemon casabonae (L.) Greuter
The Analysis of variance (ANOVA) results showed that the number of endemic species per plot was positively correlated with species richness

Summary

Introduction

Rangelands cover approximately one-third of the Earth’s land area and at least one billion people depend on these lands to live, both directly through livestock production and indirectly from other resources and ecosystem services [1,2]. They are traditionally characterized by highly heterogeneous natural vegetation communities, which often have a high conservation value, frequently grow in harsh environments [3], are associated with wildlife and/or domestic grazing, and are managed by ecological/traditional rather than agronomic methods [4]. The intensive exploitation of rangelands under high stocking rates promotes an increase in unpalatable species (e.g., poisonous, toxic, and spiny species), and a decrease in forage biomass and value, which are common indicators of land degradation [12,13]

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