Article / Book
View article.
Results show that loss of perennial herbaceous species, which can result from inappropriate livestock grazing, and loss of shrubs, which often results from fire, interact to affect key functional groups. The implications are that ecosystem resilience to disturbance in Cold Desert shrublands decreases when competition from perennial native grasses and forbs for available resources no longer prevents dominance by A. tridentata and other shrubs and/ or annual invasive grasses. Managing livestock grazing to maintain or increase perennial herbaceous species, especially deep-rooted grasses, which contribute to resilience along elevation gradients, can help prevent threshold crossings to undesirable states and retain critical ecosystem services following disturbances such as wildfire.
View article.
This study investigated the relative importance of site productivity and seasonal climate in explaining the variance in recovery time for 36 fires, comprising a fire chrono-sequence (from 1971 to 2007) for the Great Basin and Colorado Plateau. A. t. vaseyana recovery was positively related to precipitation in the cool season immediately following fire, likely because deep soil-water recharge that persists throughout the growing season enhances first-year seedling survival. Percentage sand fraction positively correlated with recovery rate yet negatively correlated with live cover in unburnt stands. Our data support the hypothesis that post-fire recovery rate of A. t. vaseyana depends on the climatically controlled ephemerality of the regeneration niche, as is likely true for many arid-land shrub species.
View article.
The burnout time for upstream shrubs increased with an increase in shrub separation distance for all shrub sizes and wind speeds considered. The burnout time for the downstream shrub was found to decrease with an increase in the separation distance, reach a minimum, and then increase with an increase in separation distance. The trends observed in burnout times for downstream shrub were attributed to the balance between heat feedback into the downstream shrub from the flames in upstream shrubs and availability of sufficient oxygen for combustion to take place.
View article.
The significant variables for the fatal injury model were fire shelter use, slope steepness and flame height. The separation distances needed to ensure no more than a 1 or 5% probability of fatal injury, without the use of a fire shelter, for slopes less than 25% were 20 to 50 m for flame heights less than 10 m, and 1 to 4 times the flame height for flames taller than 10 m. The non-fatal injury model significant variables were fire shelter use, vehicle use and fuel type. At the 1 and 5% probability thresholds for a non-fatal injury, without the use of a fire shelter, the separation distances were 1 to 2, 6 to 7, and 12 to 16 times greater than the current safety zone guideline (i.e. 4 times the flame height) for timber, brush and grass fuel types respectively.
View article.
In North America, decisions about how and when to apply prescribed fire are typically based on the historical-fire-regime concept (HFRC), which holds that replicating the pattern of fires ignited by lightning or preindustrial humans best promotes native species in fire-prone regions. This study found that the practice of inferring historical fire regimes for entire regions or ecosystems often entails substantial uncertainty and can yield equivocal results; ecological outcomes of fire suppression are complex and may not equate to degradation, depending on the ecosystem and context; and habitat fragmentation, invasive species, and other modern factors can interact with fire to produce novel and in some cases negative ecological outcomes. Although the HFRC is a valuable starting point, it should not be viewed as the sole basis for developing prescribed fire programs. Rather, fire prescriptions should also account for other specific, measurable ecological parameters on a case-by-case basis.
View article.
In this paper, optimization models successfully identified areas with low conifer canopy cover, high resilience and resistance to wildfire and annual grass invasion, and high bird abundance to enhance sage-grouse habitat. The inclusion of mesic resources resulted in further prioritization of areas that were closer to such resources, but also identified potential pathways that connected breeding habitats to the late brood-rearing habitats associated with mesic areas. Areas identified by optimization models were largely consistent with and overlapped ongoing conifer removal efforts in the Warner Mountains of south-central Oregon. Land ownership of preferential areas selected by models varied with priority goals and followed general ownership patterns of the region, with public lands managed by the Bureau of Land Management and private lands being selected the most. The increased availability of landscape-level datasets and assessment tools in sagebrush ecosystems can reduce the time and cost of both planning and implementation of habitat projects involving conifer removal. Most importantly, incorporating these new datasets and tools can supplement expert-based knowledge to maximize benefits to sagebrush and sage-grouse conservation.
View article.
Stephen Pyne is Regents Professor in the School of Life Sciences at Arizona State University. This is an abridged version of a piece that appeared on The Conversation; to read the entire piece, go to theconversation.com
View news article.
This news story provides some about the history and future of fire behavior research.
View article.
Researchers developed landscape-directed dispersal simulations and tested a series of replicates that emulate independent empirical datasets for greater sage-grouse and eastern fox snake. The study helps establish methods for using liner mixed models to identify the features underlying patterns of dispersal across a variety of landscapes.
View article.
Our results suggest that bird communities in piñon-juniper woodlands can be highly stable when management treatments are conducted in areas with more advanced woodland development and at the level of disturbance measured in our study.