Transhumant Sheep Grazing Enhances Ecosystem Multifunctionality in Productive Mountain Grasslands: A Case Study in the Cantabrian Mountains

Abstract

Understanding the effects of traditional livestock grazing abandonment on the ability of mountain grasslands to sustain multiple ecosystem functions (ecosystem multifunctionality; EMF) is crucial for implementing policies that promote grasslands conservation and the delivery of multiple ecosystem services. In this study, we evaluated the effect of short- and long-term transhumant sheep abandonment on EMF through a grazing exclusion experiment in a grassland of the Cantabrian Mountains range (NW Spain), where transhumant sheep flocks graze in summer. We considered four key ecosystem functions, derived from vegetation and soil functional indicators measured in the field: (A) biodiversity function, evaluated from total plant species evenness, diversity and richness indicators; (B) forage production function, evaluated from cover and richness of perennial and annual herbaceous species indicators; (C) carbon sequestration function, evaluated from woody species cover and soil organic carbon indicators; and (D) soil fertility function, evaluated from NH4+-N, NO3–-N, P and K content in the soil. The EMF index was calculated by integrating the four standardized ecosystem functions through an averaging approach. Based on linear mixed modeling we found that grazing exclusion induced significant shifts in the considered individual ecosystem functions and also on EMF. Long-term livestock exclusion significantly hindered biodiversity and forage production functions, but enhanced the carbon sequestration function. Conversely, the soil fertility function was negatively affected by both short- and long-term grazing exclusion. Altogether, grazing exclusion significantly decreased overall EMF, especially in long-term livestock exclusion areas, while the decline in EMF in short-term exclusions with respect to grazed areas was marginally significant. The results of this study support the sustainability of traditional transhumance livestock grazing for promoting the conservation of grasslands and their ecosystem function in mountain regions.

Burnt wood management enhances soil multifunctionality at the medium term after a large wildfire in north-west Spain

“…This study represents a first attempt to assess whether straw mulching and cut plus lopping treatments could improve soil multifunctionality in the medium term after fire. Our results support the use of a soil multifunctionality approach instead of individual soil functions or soil functional indicators for several reasons: (1) to avoid biased assumptions on management success (Lucas-Borja et al 2021); (2) to prevent the occurrence of changes in the magnitude of the overall post-fire treatment effect when considering multiple functions pooled together (Fernández-Guisuraga et al 2022); and (3) to disentangle the synergies and trade-offs between soil functions evidenced in treated and untreated areas. Contrary to our expectations, the application of straw mulch did not mediate a significant response in either individual soil functions (carbon regulation, water regulation, soil fertility and nutrient cycling) and soil multifunctionality at the medium term after fire, although their values tended to increase in heathland treated areas.…”

“…We considered that the higher the value of each raw soil functional indicator, the higher the level of the associated function (Maestre et al 2012a;Fernández-Guisuraga et al 2022), except for the WR variable, where large WDPT values are linked to hydrophobic soils and loss of soil quality and functionality worldwide (Seaton et al 2019). Therefore, raw values of the WR indicator were reflected using the function -f i + max(f i ), f i being the measures of indicator i, in this case, WR.…”

“…carbon regulation, water regulation, soil fertility and nutrient cycling), and soil multifunctionality was computed through an averaging approach of the individual functions (Maestre et al 2012a). The standardisation by the highest observed function values and the averaging approach are among the most widely used methods in the literature because of their intuitive interpretation and straightforward applicability for estimating the capacity of an ecosystem to support several functions simultaneously (Maestre et al 2012b;Byrnes et al 2014;Fernández-Guisuraga et al 2022).…”

“…EMF or soil multifunctionality evaluation instead of single functions) so as not to obtain a biased perspective of the ecosystem response to treatment or restoration success (Lucas-Borja et al 2021). Also, both the positive and negative effects of post-fire treatments may be of even greater magnitude when considering the overall ecosystem function (Maestre et al 2012a;Byrnes et al 2014;Fernández-Guisuraga et al 2022). Nevertheless, to date, the influence of post-fire mulching and burnt wood treatments on EMF, and particularly on soil multifunctionality, remains little examined in fire-prone ecosystems in the medium term after fire.…”

Landscape Implications of Contemporary Abandonment of Extensive Sheep Grazing in a Globally Important Agricultural Heritage System

“…The relevance of the transhumant system over time has given rise to the appearance of livestock breeds, such as the Merino breed, which is a highly appreciated sheep for its wool, and the traditional breed that used mountain pasturelands in Spain the last centuries; to legal regulations of transhumance since the s. VI, and more intensely since the XII century; to a network of livestock roads; to create a cultural context; and to the maintenance of ecosystem multifunctionality by sheep in the mountain pasturelands, including the conservation of productivity, diversity of habitats, ecosystem services, biological richness, and landscape structure [9,[12][13][14]. Some authors [15][16][17] attribute to these periodic livestock movements and the successive occupation of different territories the maintenance of associated fauna in the same areas, such as Neophron percnopterus, Aegypius monachus, and Gyps fulvus, which benefits from the death of any animals along the way.…”