Wildfires in Grasslands and Shrublands: A Review of Impacts on Vegetation, Soil, Hydrology, and Geomorphology

Abstract

Wildfires are prevalent in grasslands and shrublands. The objective of this study is to provide land managers with a general overview, by assessing the main impacts of wildfire, including those on plant communities (e.g., secondary succession and species invasion), soil characteristics (e.g., water repellency (hydrophobicity), aggregation and structure stability, and contents of organic carbon and nutrients), and surface processes (e.g., ash deposition, ground surface clogging, water runoff, soil erosion, hillslope debris flow, and dry ravel). Additionally, the study discusses the effects of livestock grazing on the functioning of post-fire grasslands and shrublands. Although mesic regions are mentioned, this review focuses on drylands. The comparatively low-to-moderate fuel loads that characterize grasslands and shrublands generate wildfires of relatively moderate intensity, resulting in moderate burn severity. Yet, it seems that because of decreased soil aggregate stability following burning, the hoof action of livestock that access burnt lands shortly after the fire increases the shearing and detachment of mineral material from the ground surface; this increases soil erodibility, with the possible risk of accelerated land degradation. The review ends with an assessment of general implications for environmental sustainability and health, and provides recommendations on wildfire control in rangelands, and on restoration of burnt lands.

The impact of wildfires on the Lake Skadar/Shkodra environment

“…As numerous studies have shown, the impact of wildfires on vegetation depends on many factors such as the seasonality of burning (Wright, 1974), the presence of different phenological stages at the burn time (Ruckman et al, 2012) and of the dominant type of vegetation. The shrubland vegetation, which dominates the surroundings of Lakes Skadar/Shkodra and Šas that were exposed to fires, is generally characterized by low-to-moderate fuel loads resulting in a relatively lower fire intensity, and consequently a relatively moderate impact on the soil (Stavi, 2019). For example, Malkinson & Wittenberg (2015) reported neutral to a positive effect of wildfires on vegetation in the dry, sub-humid north of Israel.…”

“…For example, Malkinson & Wittenberg (2015) reported neutral to a positive effect of wildfires on vegetation in the dry, sub-humid north of Israel. Most studies that have addressed the impact of fire on vegetation have shown that this impact is highly site-specific and can be either negative or positive (Deák et al, 2014;Stavi, 2019).…”

Seeking Environmental Sustainability in Dryland Forestry

“…Furthermore, afforestation and reforestation projects are more successful when comprised of mixed tree species, which are less susceptible to infestation by pests and diseases than single-species plantations [25]. Regardless, the increase in frequency and intensity of droughts around the world, driven by climate change, lead to mass drying and mortality of trees, resulting in increased incidence and aggravated intensity of wildfires [26,27]. Therefore, preference should be given for the selection of drought-tolerant, fire-resistant, and less flammable tree species [28].…”

Temporal Patterns of Large Wildfires and Their Burn Severity in Rangelands of Western United States

“…Studies in forest ecosystems have shown that total land area burned and area burned at high severity increased in general (Dillon et al., 2011; Rollins, 2009; Singleton et al., 2019), while trends in the proportion of areas burned at high severity varied among regions in western United States (Miller et al., 2012; Nigro & Molinari, 2019). Although wildfires are common and extensive in many rangelands which are fire‐dependent ecosystems (Fuhlendorf et al., 2011), rangelands have low to moderate fuel loads compared to forests and tend to have fires with low and moderate burn severity (Stavi, 2019).…”