Goat grazing reduces diversity and leads to functional, taxonomic, and phylogenetic homogenization in an arid shrubland

Abstract

Livestock production is an important activity in drylands. However, lack of adequate regulation of ranching activities can lead to the degradation of plant communities, which in turn can impact ecosystem functioning. In the arid ecosystems of north‐central Chile, unregulated goat grazing is widespread. Because the vegetation has a relatively short evolutionary history of grazing, it is expected to be highly susceptible to this activity. In this study, we evaluated the effects of goat grazing on plant taxonomic, functional, and phylogenetic community structure by comparing 39‐year‐old grazing exclusion plots and unprotected plots in an arid shrubland in north‐central Chile. By integrating analyses of the impact of goat grazing on functional and phylogenetic diversity and dispersion, we studied the mechanisms behind goat impact and the potential consequences. Loss of functional and/or phylogenetic diversity can result in important losses in ecosystem function. As a measure of functional diversity, we recorded plant growth form, life span, and life form. We also reconstructed a phylogeny of all plant species found at the study site and determined the phylogenetic structure of the plant community in ungrazed and grazed areas. We found that goat grazing affected diversity and community composition, leading to taxonomic, functional, and phylogenetic biotic homogenization and causing overall community impoverishment. Goats acted as a habitat filter, increasing functional convergence and promoting the establishment of exotics plants, which can lead to further losses of biodiversity, decreased ecosystem function and overall lower ecosystem stability. Our results indicate that sustainable management strategies are necessary to prevent the further degradation of these ecosystems.

Changes in functional, phylogenetic and taxonomic diversities of lowland fens under different vegetation and disturbance levels

“…Historically, the main objectives of vegetation management applied to open fens have been to prevent the development of fen carr vegetation and to maintain characteristic species of herbaceous fens (Stammel et al 2003). However, our results and other findings (Salgado-Luarte et al 2019) should help to inform discussions about fen management in the UK. Even if challenging from a practical standpoint, monitoring functional and phylogenetic diversities is a worthwhile aid to enhance management strategies.…”

Introduced goats reduce diversity and biomass of herbs in Caatinga dry forest

“…Overgrazing usually leads ecosystems to alternative stable states of low value for people due to ecological collapse, such as low productive deserts (Manzano & Návar, 2000). In the long-term, goats reduced both functional and phylogenetic diversity of plant communities in a Chilean semi-desert landscape (Salgado-Luarte et al, 2019).…”

Long-Term Enclosure Can Benefit Grassland Community Stability on the Loess Plateau of China

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“…Some studies found that community stability decreased with increasing the level of N fertilization [1,4,6], but a few other studies found that long-term N fertilization increased community stability via enhancing species dominance [7]. Grazing has been found to decrease community stability [8,9], while long-term…”