DISCLAIMER: I am not a lawyer nor do I play one on TV. I am not a land manager either, nor do I speak for any of them. This is just the way I am seeing things and interpreting the various laws.
To begin with, fossils have been widely protected across all public lands under the Antiquities Act of 1906 as "objects of antiquity," but are not explicitly called out in the law, so this protection has been up to some interpretation over the years. In any case it has been understood that for over 100 years fossil remains have some sort of "special" status beyond that of mere rocks or geological oddities.
https://www.nps.gov/subjects/legal/the-antiquities-act-of-1906.htm
The next major piece of legislation is the Archaeological Resources Protection Act of 1979, and it has been widely mentioned in media recently (especially from the vantage point of those looking to defend the reductions). Interestingly, ARPA specifically excludes fossils from protection. From ARPA, 16 U.S.C. 470bb, Definitions, Section 3" Nonfossilized and fossilized paleontological specimens, or any portion or piece thereof, shall not be considered archaeological resources, under the regulations under this paragraph, unless found in an archaeological context. No item shall be treated as an archaeological resource under regulations under this paragraph unless such item is at least 100 years of age."
https://www.nps.gov/history/local-law/fhpl_archrsrcsprot.pdf
Legislatively the most recent thing, the Paleontological Resources Preservation Act of 2009 does lay out specific protections and rules for fossils, including vertebrates, invertebrates, and plants. Each land management agency is tasked with coming up with PRPA-compliant management plan. Under PRPA, casual collection of invertebrate and plant fossils found on the surface is allowed from public. The collection of vertebrate fossils requires a permit.
http://vertpaleo.org/The-Society/Advocacy/Paleontological-Resources-Preservation-Act.aspx
The two biggest issues, in terms of actual on-the-ground protection right now (instead of in a decade when there is a Monument Management Plan implemented and in the FR) is that some fossils are indeed no longer protected when a monument's boundaries are shrunk; specifically plant and invertebrate fossils (which are really important for interpreting the ancient environment and can be highly significant in and of themselves). Anyone can legally collect those now, whereas in the 2016 proclamation it said, " Warning is hereby given to all unauthorized persons not to appropriate, injure, destroy, or remove any feature of the monument and not to locate or settle upon any of the lands thereof." Those items were protected from collection then, and now they are not. Additionally the monument provides protection from development (specifically commercial development), whereas multi-use BLM lands require monitoring and mitigation of projects (roads, powerlines, mining, hiking trails, etc.) that might disturb fossil resources. The fossils do not have the same level of protection on multi-use BLM lands as they do as "objects to be conserved" in a monument where they are an explicit priority for management.
https://obamawhitehouse.archives.gov/the-press-office/2016/12/28/proclamation-establishment-bears-ears-national-monument
The next major piece of legislation is the Archaeological Resources Protection Act of 1979, and it has been widely mentioned in media recently (especially from the vantage point of those looking to defend the reductions). Interestingly, ARPA specifically excludes fossils from protection. From ARPA, 16 U.S.C. 470bb, Definitions, Section 3" Nonfossilized and fossilized paleontological specimens, or any portion or piece thereof, shall not be considered archaeological resources, under the regulations under this paragraph, unless found in an archaeological context. No item shall be treated as an archaeological resource under regulations under this paragraph unless such item is at least 100 years of age."
https://www.nps.gov/history/local-law/fhpl_archrsrcsprot.pdf
Legislatively the most recent thing, the Paleontological Resources Preservation Act of 2009 does lay out specific protections and rules for fossils, including vertebrates, invertebrates, and plants. Each land management agency is tasked with coming up with PRPA-compliant management plan. Under PRPA, casual collection of invertebrate and plant fossils found on the surface is allowed from public. The collection of vertebrate fossils requires a permit.
http://vertpaleo.org/The-Society/Advocacy/Paleontological-Resources-Preservation-Act.aspx
The two biggest issues, in terms of actual on-the-ground protection right now (instead of in a decade when there is a Monument Management Plan implemented and in the FR) is that some fossils are indeed no longer protected when a monument's boundaries are shrunk; specifically plant and invertebrate fossils (which are really important for interpreting the ancient environment and can be highly significant in and of themselves). Anyone can legally collect those now, whereas in the 2016 proclamation it said, " Warning is hereby given to all unauthorized persons not to appropriate, injure, destroy, or remove any feature of the monument and not to locate or settle upon any of the lands thereof." Those items were protected from collection then, and now they are not. Additionally the monument provides protection from development (specifically commercial development), whereas multi-use BLM lands require monitoring and mitigation of projects (roads, powerlines, mining, hiking trails, etc.) that might disturb fossil resources. The fossils do not have the same level of protection on multi-use BLM lands as they do as "objects to be conserved" in a monument where they are an explicit priority for management.
https://obamawhitehouse.archives.gov/the-press-office/2016/12/28/proclamation-establishment-bears-ears-national-monument
Is it accurate to say that fossils have lost protections under the Trump proclamations? Yes. Some fossils are explicitly no longer protected in any substantive way (such as invertebrate fossils and plants), while others (vertebrates) retain their PRPA protections but don't enjoy a special status among the other possible uses for the land. So all fossils from an excluded area lose some protections, and some fossils lose virtually all of their protections. That nuance has been lost in many of the articles that have come out about some of our BENM work recently so I figured I would put this out there and hope that maybe those of you who are interested will find this post educational.