Impact of Grazing on Diversity of Semi-Arid Rangelands in Crete Island in the Context of Climatic Change

Abstract

The rangelands of Crete island (Greece) are typical Mediterranean habitats under high risk of degradation due to long-term grazing and harsh climatic conditions. We explored the effect of abiotic (climatic conditions, altitude) and biotic factors (long-term grazing by small ruminants) on the floristic composition and diversity of selected lowland (Pyrathi, Faistos) and highland (Vroulidia, Nida) rangelands. In each rangeland, the ground cover was measured, and the floristic composition was calculated in terms of five functional groups: grasses, legumes, forbs, phrygana, and shrubs. The aridity index, species turnover, species richness, Shannon entropy, and Gini–Simpson index (with the latter two converted to the effective number of species) were calculated. Our results reveal that highlands are characterized by the highest aridity index (wetter conditions). Lowland rangelands, compared to highland, exhibited a higher percentage contribution of grasses, legumes, and forbs, while species turnover decreased along the altitudinal gradient. The Shannon entropy index was correlated (a) positively with Gini–Simpson and mean annual temperature and (b) negatively with mean annual precipitation, aridity index, and altitude. Moreover, the Gini–Simpson index correlated positively with mean annual temperature and negatively with altitude. Our results could help to understand the effects of grazing on rangeland dynamics and sustainability in semi-arid regions in the context of climatic change.

Soil salinity drives vegetation changes by grazing exclusion in semiarid regions

“…This is consistent with previous studies in the semiarid rangelands (e.g. Li et al, 2012;Wang et al, 2014;Bakhshi et al, 2020;Karatassiou et al, 2022;Li et al, 2022). In general, livestock herbivores like sheep primarily focus on forage quality, having a high selectivity in grazing on plants (e.g.…”

“…The vegetation cover was recorded in the quadrats by visual estimation of each plant species in each quadrat (Heady and Child, 1994). It is known that the cover of vegetation is a health indicator of the rangelands (Karatassiou et al, 2022). In addition, 5 soil cores were randomly collected and combined for each quadrat for chemical analyses.…”

Wildfire Effects on Rangeland Health in Three Thermo-Mediterranean Vegetation Types in a Small Islet of Eastern Aegean Sea

“…The floristic composition was calculated from plant cover measurements and classified into four functional plant groups: grasses, legumes, forbs, and woody. Legumes were presented separately from forbs because of their nutritional importance for small ruminants [26]. Floristic diversity, evenness, and dominance were determined for each transect [27] by the number of species, the Shannon-Wiener diversity index (H ), the Simpson diversity index (D), the Buzas and Gibson evenness (E) and the Berger-Parker dominance index (d) [28][29][30].…”

Impact of Transhumant Livestock Grazing Abandonment on Pseudo-Alpine Grasslands in Greece in the Context of Climatic Change

“…Land 2022, 11, 2126 2 of 18 Species diversity, ecosystem function and landscape structure in pseudo-alpine grasslands, like most terrestrial ecosystems, are concurrently affected by global climate change and anthropogenic activities such as livestock grazing, agriculture, urbanization, etc. [12][13][14][15][16][17][18]. Changes in vegetation pattern and floristic composition are the main effects of livestock grazing on the landscape.…”

“…Changes in vegetation pattern and floristic composition are the main effects of livestock grazing on the landscape. The nature and extent of these changes depend on livestock species [19], grazing period, pressure, and history [20][21][22], as well as on abiotic variables such as soil type, temperature, and precipitation [15,23].…”