Detecting trends in the quality and productivity of grasslands by analyzing the historical vegetation relevés: A case study from Southeastern Carpathians, Vlădeasa Mountains (Romania)

Teodor Marușca,Elena Taulescu,Tudor M Ursu,Anamaria Roman,Răzvan D Popa

doi:10.15835/nbha49312378

Abstract

Grassland ecosystems are essential for biomass production but are prone to degradation if management practices are inappropriate. Thus, it is necessary to optimize grazing management since the grazing practices and grassland status are interconnected. Herbage mass production and forage quality of the plant species are among the most important factors for grazing livestock performance, grassland carrying capacity, and their sustainable management. We employed optimized methods for the analysis of two historical vegetation datasets (from 1970 and 2008), along with the statistical data on livestock numbers and types from three administrative units within the Vlădeasa Mountains area, in the Romanian Carpathians. We looked for trends in grassland quality and productivity and explored their connections to grazing management descriptors and practices. We identified a small but statistically significant decreasing trend between the two periods in both pastoral value (from 63.80 to 61.43) and productivity (from 10.80 t ha-1 to 9.18 t ha-1). The decline in grassland quality and productivity may be associated with the sharp decrease in livestock numbers (from 9,688 LU to 5,085 LU) and the replacement of cattle by sheep as the dominant livestock type. The abandonment of grasslands and traditional practices also increased the deviation from the optimum of the actual stocking rate. This approach can be used as a model for other areas where time-series vegetation data are available from phytosociological literature and/or databases. These insights can be used to design adaptive grazing management plans to optimize grazing management according to the carrying capacity of the grassland ecosystems.

Highlights

Grasslands are semi-natural ecosystems that are essential for biomass production, providing the basis for farming and grazing, but they are prone to degradation if management practices are inappropriate (White et al, 2000; Hopkins and Holz, 2006; Wick et al, 2016; Török et al, 2018a; Roman et al, 2019)
The decline in grassland quality and productivity may be associated with the sharp decrease in livestock numbers and the replacement of cattle by sheep as the dominant livestock type
The decline in grassland quality and productivity may be associated with the sharp decrease in livestock numbers and with the replacement of cattle by sheep as dominant livestock type

Summary

Introduction

Grasslands are semi-natural ecosystems that are essential for biomass production, providing the basis for farming and grazing, but they are prone to degradation if management practices are inappropriate (White et al, 2000; Hopkins and Holz, 2006; Wick et al, 2016; Török et al, 2018a; Roman et al, 2019). As part of describing and mapping vegetation types, phytosociology experts gathered a huge amount of semi-quantitative data, as vegetation relevés, available either in literature or centralized in databases (Vassilev et al, 2018; Bruelheide et al, 2019), that are valuable resources for estimating the potential productivity of a grassland or for grazing planning Most of these relevés estimate species cover-abundance using the seven-grade scale of Braun-Blanquet (1964), which has an inter-class variation range of 20% (class 2) respectively 25% (class 3, 4 and 5). Can we associate the observed changes in the grasslands quality and productivity descriptors (pastoral value, herbage mass production, optimum stocking rate) to grazing management descriptors and practices (actual stocking rate, deviation from optimum stocking rate, livestock types)?

Materials and Methods

Results and Discussion

Conclusions