Biological invasion threatens keystone species indelibly entwined with Indigenous cultures

Abstract

Black ash (Fraxinus nigra), the most highly preferred and vulnerable host of the invasive emerald ash borer (EAB; Agrilus planipennis) in North America, is of cultural and spiritual importance to many Tribal Nations in the US and First Nations in Canada. To date, EAB has invaded nearly 60% of the native range of black ash, with annual spread averaging approximately 50 km per year. On the basis of the predicted expansion of EAB distribution, we estimate that more than 75% of black ash basal area will be lost across 87% of the species’ North American range by 2035. Census data indicate that 98% of Indigenous people currently residing within the geographic range of black ash in the US will be within the area experiencing more than 75% basal area loss by 2035, suggesting broad and multidimensional impacts of EAB invasion for those who value black ash as a cultural keystone species. Collaborative efforts among scientists, resource managers, and Indigenous experts are needed to mitigate EAB impacts and preserve or protect black ash resources, given the species’ vulnerability to EAB and its associated cultural and ecological value.

Spread management priorities to limit emerald ash borer (Agrilus planipennis) impacts on United States street trees

“…Quarantines limiting the spread of propagules from the managed site prevailed in the core of the infested area. This suggests a refocusing from a more contiguous exit quarantine boundary to a pattern that aligns with the pockets of new long-distance establishments typical of EAB spread (Siegert et al, 2023). This could be implemented by having the steepest exit regulations in sawmills near major urban hubs and a targeted increase in wood entry restrictions to areas highest in both ash trees and humans.…”

“…Ash basketmaking is a longstanding tradition and livelihood for Indigenous peoples in the Great Lakes region and the Eastern US and Canada, including for the Anishinaabe people, and peoples within the Haudenosaunee (Iroquois) and Wabanaki confederacies. However, many weavers have been forced to abandon the practice due to a lack of viable ash trees (Benedict & David, 2004;Poland et al, 2015;2017;Siegert et al, 2023).…”

Can’t carve air, can’t weave names: Plant species used in Colombian artisan crafts are not equally assessed for vulnerability at the international and national level

“…Similarly, the term “cultural keystone species (CKS)” was originally coined to describe “culturally salient species that shape in a major way the cultural identity of a people, as reflected in the fundamental roles these species have in diet, materials, medicine, and/or spiritual practices” (Garibaldi & Turner, 2004). For example, kalo (taro, Colocasia esculenta) is a primary staple in Hawaiian Indigenous cuisine (Winter, Lincoln, & Berkes, 2018), Black ash ( Fraxinus nigra ) has medicinal and ceremonial importance for multiple Tribal Nations in North America (Siegert et al, 2023), and guassa grass ( Festuca macrophylla ) has many uses for communities living in the northern highlands of Ethiopia, including food, clothes, and building material (Chengere et al, 2022). CKS has a similarly narrow definition to EKS, as it looks specifically at species whose loss would lead to major cultural changes and whose initial absence would likely have resulted in major differences in the resulting culture(s), like the functioning of economy, food security, and utility (Garibaldi & Turner, 2004).…”

Observations of reduced ET and persistent elevated water table beneath a riparian forest gap following emerald ash borer invasion and tree mortality

“…These forests are particularly vulnerable to EAB-induced mortality and cascading after-effects because the ash species that are typically abundant in these landscapes, black ash (Fraxinus nigra) and green ash (F. pennsylvanica) (Kennedy, 1990;Wright & Rauscher, 1990), are also the most highly preferred and vulnerable ash species encountered by EAB in eastern North America McCullough, 2019;Tanis & Mccullough, 2015). Post-invasion mortality of 79%-99% of overstory black ash and green ash trees has been consistently reported (Burr & McCullough, 2014;Kashian et al, 2018;Klooster et al, 2014;Knight et al, 2014;Siegert et al, 2021Siegert et al, , 2023Smith et al, 2015). Loss of dominant and abundant ash species in riparian corridors can affect forest composition, leaf litter quality, biogeochemical cycling of carbon and nitrogen, light availability, soil water content, along with stream temperatures and other attributes (e.g., Broadmeadow & Nisbet, 2004;Huddleston, 2011;Larson et al, 2023;Lovett et al, 2004;Nisbet et al, 2015;Slesak et al, 2014;Wallace et al, 1997).…”

“…Documenting the response of riparian forest ecosystems following EAB invasion is critical for projecting long term impacts of this disturbance and developing potential restoration efforts. To date, the scientific community has amassed two decades of research detailing numerous economic and ecological impacts from the EAB invasion of North America (e.g., Aukema et al 2010;Kovacs et al, 2010;Larson et al, 2023;Lovett et al 2016;McCullough, 2019;Siegert et al, 2021) and is beginning to elucidate the vast and cascading implications of the functional loss of overstory ash (e.g., COSEWIC, 2018;D'Amato et al, 2018;Davis et al, 2019;Flower et al, 2013;Fraver et al, 2022;Gandhi & Herms, 2010;Klooster et al, 2014Klooster et al, , 2018Kolka et al, 2018;Larson et al, 2023;Siegert et al, 2023). Substantial knowledge gaps, however, remain in our understanding of how overstory ash mortality may affect hydrologic processes in impacted environments including riparian forests.…”