The ordinance spurred the westward movement of American settlers

Assisted migration should consider the critical, in situ preservation of adapted species and populations at the trailing edges of changing ranges because, compared to leading edge populations, they have unique features that were important for maintenance of biodiversity during previous shifts in climate (Hampe and Petit 2005).

17. Conquering the West | The American Yawp

The first quarter of the nineteenth century was marked by westward migration into the ..
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Native Americans long dominated the vastness of the American West

This makes us ripe for criticism from those who object to 'assisted migration' largely because of the demonstrated abilities of humans to create ecological havoc, centered primarily on the concept of invasiveness (see Mueller and Hellman 2008).

Westward Expansion | HistoryNet

Seed transfer guidelines, because they determine transfer distances that avoid maladaptation (Johnson and others 2004) and can be re-projected using models of expected future environmental conditions (Thomson and others 2010), will play an integral role in the planning of assisted migration efforts under global change.

This migration westward placed them in conflict with other tribes which often resulted in hostilities.
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Trails West - Westward Expansion

This normative shift has real material consequences, such as enabling the movement of western larch 1000 km north of its current distribution, sidestepping the issue of its ecological appropriateness in the recipient ecological community, because from a 'climate fitness' perspective, western larch may eventually migrate to northern BC.
Thus given the genetical frame structuring the AM policy coordinative discourse, we argue that there is a major shift in the cognitive and normative content of ideas at the program level.

The Oregon Trail: Westward Migration to the Pacific Ocean ..

Nonetheless, this is a very interesting example of how a grassroots organization can pro- pel assisted migration into the forefront, causing a govern- mental agency to consider the use of this strategy."

Chapter 7: As Long As Grass Grows Or ..

The documents do not show when or what place of origin for these settlers. Following the majority of migration, Owen families as well as others seemed to primarily spread inland in a north and westerly direction.

Atrocities Against Native Americans - United to End Genocide

What I found was that the debate seemed to be stuck around what we call 'other issues' — neither direct risks nor benefits to implementing a particular assisted migration, but rather, counter arguments to the opposite side of the debate. These counter arguments need to be distinguished from direct risks and benefits because they can't provide justification for scrapping or adopting the policy."

U.S. History - The Westward Spirit - CoolJargon

Similarly, what is the ethical or scientific justification for prohibiting or removing any organism simply because it never existed in a particular location, especially if that organism is now well‐matched with the location due to changes in climatic conditions?"Page 253: "Though this Article provides a preliminary framework for assessing both when to allow and how to manage experimentation with assisted migration, it more importantly explains how climate change reveals a host of value questions that remain unexplored in natural resource law and policy.