Regeneration dynamics of woody vegetation in a Mediterranean landscape under different disturbance‐based management treatments

Abstract

Question Mediterranean landscapes have been affected for millennia by agro‐pastoral disturbances such as grazing and vegetation clearing. Increased levels of fine‐scale habitat heterogeneity that resulted from these disturbances contribute to reduced wildfire risk and increased species diversity. Disturbance‐based management tools utilize disturbances in order to promote biodiversity and reduce fire risk, but are complicated to apply effectively due to the natural regeneration ability of many woody species following disturbances. Therefore, their successful application requires a better understanding of woody regeneration dynamics. Here, we asked how disturbance‐based management treatments affected the spatiotemporal dynamics of woody vegetation across 11 yrs in a Mediterranean landscape. Location Ramat HaNadiv LTER, northern Israel. Methods We analysed vegetation dynamics in a field experiment comprising five treatments: cattle grazing, goat grazing, shrub clearing, shrub clearing followed by goat grazing and undisturbed control. We used image analysis of high‐resolution aerial photographs to map woody patches in our study plots. We then quantified the spatial pattern of woody vegetation using multiple landscape indices, and conducted a comparative analysis of woody regeneration rates under different management treatments. Results Cattle grazing did not inhibit woody regeneration, as regeneration rates were similar to those found in undisturbed control plots. Shrub clearing led to rapid woody regeneration (7% yr−1), while a combination of shrub clearing and intense goat grazing halted woody regeneration completely. Finally, intense goat grazing not only prevented woody regeneration but led to significant decline in woody cover (1% yr−1). Conclusions Our results highlight the rapid regenerative response of woody vegetation to severe disturbances, and the growth rates we found can serve as guidelines for long‐term management regimes aimed at maintaining low woody cover and biomass in fuel breaks and buffer zones.

Optimizing the Timing of Unmanned Aerial Vehicle Image Acquisition for Applied Mapping of Woody Vegetation Species Using Feature Selection

“…However, previous studies indicate that the East Mediterranean woody species are not necessarily an easy target for classification by remote sensing. Most local vegetation formations are characterized by densely-growing evergreen species, often with similar spectral properties [58][59][60], small intra-annual differences [61] and morphological similarities [62][63][64][65]. To the best of our knowledge, there are currently no studies that use high spatial resolution imagery with a limited number of bands for the classification of East Mediterranean common species.…”

Effects of large herbivores on fire regimes and wildfire mitigation

“…In other cases, grazing does not alter the amount of fuel but rather its composition, reducing the herbaceous layer and increasing tree regeneration (Briggs et al, 2002;Zimmerman & Neuenschwander, 1984). The ability of herbivores to reduce fuel loads also depends on the season (Davies et al, 2016) and associated management, such as controlled burning (Bashan & Bar-Massada, 2017) or mechanical clearing (e.g. Etienne et al, 1995).…”

“…While herbivores are often effective in reducing vegetation biomass and therefore fire hazard, there are also studies reporting mixed (Bashan & Bar-Massada, 2017;Briggs et al, 2002;Travers et al, 2020) or nonsignificant effects (e.g. Calleja et al, 2019;Dittel et al, 2018).…”

Using field and nursery treatments to establish Quercus suber seedlings in Mediterranean degraded shrubland

“…Some of these treatments have focused on improving root system structure and growth to increase water uptake and to avoid water stress (Chirino et al 2008, Mariotti et al 2015b. Other studies have reduced incoming solar radiation stress (Bellot et al 2002) or competition with coexisting vegetation by shrubland management techniques (Pérez-Devesa et al 2008, Bashan & Bar-Massada 2017. However, in most studied cases, the different reforesta-tion techniques followed to improve seedling introduction into degraded shrubland have been analyzed individually and have not been combined.…”