Operationalizing Resilience and Resistance Concepts to Address Invasive Grass-Fire Cycles

Abstract

Plant invasions can affect fuel characteristics, fire behavior, and fire regimes resulting in invasive plant-fire cycles and alternative, self-perpetuating states that can be difficult, if not impossible, to reverse. Concepts related to general resilience to disturbance and resistance to invasive plants provide the basis for managing landscapes to increase their capacity to reorganize and adjust following fire, while concepts related to spatial resilience provide the basis for managing landscapes to conserve resources and habitats and maintain connectivity. New, spatially explicit approaches and decision-tools enable managers to understand and evaluate general and spatial resilience to fire and resistance to invasive grasses across large landscapes in arid and semi-arid shrublands and woodlands. These approaches and tools provide the capacity to locate management actions strategically to prevent development of invasive grass-fire cycles and maintain or improve resources and habitats. In this review, we discuss the factors that influence fire regimes, general and spatial resilience to fire, resistance to invasive annual grasses, and thus invasive grass-fire cycles in global arid and semi-arid shrublands and woodlands. The Cold Deserts, Mediterranean Ecoregion, and Warm Deserts of North America are used as model systems to describe how and why resilience to disturbance and resistance to invasive annuals differ over large landscapes. The Cold Deserts are used to illustrate an approach and decision tools for prioritizing areas on the landscape for management actions to prevent development of invasive grass-fire cycles and protect high value resources and habitats and for determining effective management strategies. The concepts and approach herein represent a paradigm shift in the management of these ecosystems, which allows managers to use geospatial tools to identify resilience to disturbance and resistance to invasive plants in order to target conservation and restoration actions where they will provide the greatest benefits.

Fire and development influences on sagebrush community plant groups across a climate gradient in northern Nevada

“…, Chambers et al. ). Components of the sagebrush communities in northern Nevada varied in their associations with climate, burn severity, number of fires, vegetation restoration and treatment, and cumulative development.…”

“…To manage and conserve the sagebrush biome and the ecological services it provides, an understanding of resistance to invasions and resilience following perturbations is advantageous (Davies et al 2011, Chambers et al 2019). Components of the sagebrush communities in northern Nevada varied in their associations with climate, burn severity, number of fires, vegetation restoration and treatment, and cumulative development.…”

“…Grazing reduces bunchgrass cover and biological soil crusts, which increases gaps for B. tectorum to exploit, especially following or preceding fire (Reisner et al 2013, Condon and. Therefore, considering interactions between combinations of disturbances, increased data availability about disturbances in the sagebrush communities, and multi-scale approaches are needed to understand sagebrush biome resilience and resistance to invasion (e.g., Reisner et al 2013, Bansal and Sheley 2016, Bradley et al 2017, Condon and Pyke 2018, Chambers et al 2019).…”

“…Climate, fire, and development interact across temporal and spatial scales in the Great Basin, with implications for the resilience and resistance to invasion of communities (Chambers et al 2019). While resilience and resistance to invasion in the sagebrush biome are well studied for fire presence and frequency, the impacts of burn severity on sagebrush communities and combined influence of disturbances need further investigation (Rowland et al 2010, Miller et al 2013.…”

Climate-Driven Shifts in Soil Temperature and Moisture Regimes Suggest Opportunities to Enhance Assessments of Dryland Resilience and Resistance

“…Quantitative evaluation of climate vulnerability and ecological resilience to global change at broad spatial scales requires widely available information about relevant environmental conditions that influence how ecosystems respond to stressors like drought, invasive species, and disturbance (Chambers et al, 2019a). In dryland regions, soil temperature and moisture regimes are widely utilized as foundational indicators of resilience to disturbances, such as wildfire, and resistance to invasive plants, such as non-native annual grasses (Chambers et al, 2019b). By estimating how longterm climate trajectories will alter these regimes, our results provide insight into potential refinements that may help existing landscape-scale assessments of resilience and resistance better capture dryland ecological dynamics in a shifting climate.…”