Fire and land cover change in the Palouse Prairie–forest ecotone, Washington and Idaho, USA

Abstract

Background Prairie–forest ecotones are ecologically important for biodiversity and ecological processes. While these ecotones cover small areas, their sharp gradients in land cover promote rich ecological interaction and high conservation value. Our objective was to understand how historical and current fire occurrences and human development influenced the Palouse Prairie–forest ecotone. We used General Land Office survey field notes about the occurrence of bearing trees to locate historical (1870s to 1880s) prairie, pine savanna, and forest at the eastern edge of the bioregion. We combined LANDFIRE Existing Vegetation classes to contrast historical land cover with current land cover. We reconstructed historical fire occurrence (1650 to 1900) from fire-scarred trees. We used fire and lightning records from 1992 to 2015 to interpret the role of people and lightning. Results Historically, the ecotone was a matrix of prairie with extensive savanna and some forest. More than half of the ecotone area was prairie, which is now dominated by agriculture, with some residential development. The 16% of the landscape that was pine savanna is now forest or shrubs, agriculture, perennial vegetation under the Conservation Reserve Program, or developed; no savanna now exists. Forests covered 12% of the ecotone and these are still mostly forest. Fires were historically frequent, occurring on average every 5 to 8 years at most sites. Lightning was not frequent but could likely have been sufficient to ignite fires that could spread readily given the rolling terrain and long fire season. Conclusions Fire was far more frequent historically than currently. Conservation, restoration, and other ongoing land-use changes will likely result in more continuous vegetation and hence fuel for fires. Lightning and people may ignite fires that therefore spread readily in the future. Understanding the past and potential future of fire in the Palouse Prairie bioregion may help us live with fire while conserving ecological values here and in similar prairie–forest ecotones.

Ants of the Palouse Prairie: diversity and species composition in an endangered grassland

“…Luckily, once taxonomic resources are available, assessment of an ecosystem’s ant communities can be completed quickly with greater accuracy of species-level identification ( Ellison et al 2007 ). The intermediate levels of ant diversity at sites adjacent to forest validate predictions that Palouse Prairie-forest ecotones may support high biodiversity ( Morgan et al 2020 ) Finally, our estimates of a species pool of 27 reflect similar scales of ant species richness found in large ant surveys in grassland systems, such as Wisconsin, USA tallgrass prairie (29 species in control sites, Kim et al 2018 ) and Argentinian grasslands (46 species in grassland sites, Santoandré et al 2019 ). However, given our absolute species richness was 17, there is more sampling to be completed to comprehensively describe this fauna.…”

Forb community response to prescribed fire, livestock grazing, and an invasive annual grass in the Pacific Northwest Bunchgrass Prairie

“…The arrival and settlement of Euro‐Americans in the late 1800s brought larger herds of cattle, sheep, and horses, and cultivation associated with homesteading (Bartuszevige et al, 2012). Although the ZPP is lacking a complete fire record, these grassland communities likely burned every 10–20 years based on climate and fuel conditions (Black et al, 1998; Bartuszevige et al, 2012; Morgan et al, 2020). It is reasonable to presume Euro‐Americans altered the fire regime through suppression efforts and by decreasing fine fuels when their livestock herds consumed herbaceous vegetation (Bartuszevige et al, 2012).…”

Estoque de carbono e agregação do solo sob diferentes sistemas de uso no cerrado

“…O bioma cerrado é uma região que sofre constantemente com o avanço das extensões agropecuárias, principalmente pelas características do solo, que favorece a mecanização (GUARESCHI; PEREIRA; PERIN, 2016;SANO et al, 2010). As regiões consideradas ecótonos são muito importantes pelas diferentes interações ecológicas e pela biodiversidade presente nessas áreas (MORGAN et al, 2020). Estudos de QS em áreas de interesse ecológico e ambiental são de extrema importância, sobretudo para gerar informações estratégicas para monitoramento e conservação.…”