Grassland Fragmentation: Introduction to the Special Issue

YEZZI, ALEJANDRA; NEBBIA, ANA; ZALBA, SERGIO

Diversity

MDPI

Año: 2023 vol. 15 p. 1 - 2

The fragmentation of natural environments is one of the most cited causes of the lossof biological diversity, and consequently it has received a great deal of attention from thescientific community for decades. In its simplest definition, fragmentation is thedisruption of continuity. Some authors consider fragmentation independent of habitatloss, and define it at the landscape scale as a pattern of spatial arrangement of the remaininghabitat after anthropogenic disruption. This concept has been so widely adopted that ithas become an entrenched paradigm in conservation studies. Authors often emphasizethe dependence of changes on the amount of habitat remaining and the spatial displayof the fragments, and define fragmentation as a process by which habitat loss results inthe division of a continuous natural environment into two or more smaller fragments,separated from each other by a matrix of modified habitat. Fragmentation affectsnatural environments through the reduction in area of the remaining habitat, the isolationof the fragments and the influence of the matrix through the resulting edges. Thesechanges drive alterations in species richness, reductions in population sizes, loss of geneticdiversity and changes in landscape structure, among other effects. The small size ofthe fragments, their isolation, the edge effect and the increased vulnerability to extrinsicdisturbances have been postulated as forces that are key to the loss of biodiversity.Fragmentation has been extensively studied in forest ecosystems, in which the mostcommon process is the transformation of the landscape into a matrix of savannas or shrublands that surrounds and isolates forest remnants. Much less is known about theconsequences of the subdivision of natural grasslands. Grassland ecosystems are essentialfor sustaining ecological services such as soil protection and prevention of erosion, themaintenance of the water cycle, the regulation of atmospheric gases, pollination and foodproduction, in addition to hosting a great genetic diversity. In spite of this, grasslandsare recognized as the terrestrial biomes that are most at risk worldwide due to the greatdisparity between the rate of habitat loss and the degree of effective protection.Due to the aptitude of their soils, natural grasslands of temperate and subtropical regionsof the world have been almost completely transformed into agricultural fields, andremnants persist as archipelagos of ever smaller and ever more isolated patches.This Special Issue of Diversity brings together two studies that approach this problemfrom different perspectives. They both refer to Eastern European grasslands which are notexempt from the situation described above. Previously, they occupied wide extensionsin the Biogeographical Region of Pannonia, and at present they have been reduced tofragments that are considered biodiversity hotspots.