New Mexico listed the New Mexico meadow jumping mouse (NMMJM) as threatened in 1983, but these mammals continued to gradually decline until they were “uplisted” as endangered in 2014 by the US Fish and Wildlife Service. Their endangerment is largely due to loss of dense grass habitat, often along riparian corridors or in mountain meadows, that can be impacted from cattle grazing, wildfires, road construction, and climate change. Decreasing water availability due to drought in areas where these mice are normally found (USGS.gov) also may impact these semi-aquatic rodents who are rarely found farther than a few feet away from running water. They require a riparian habitat that make up less than 1% of landmass in the southwestern United States. The already limited number of streams has been deteriorating, leaving the mice with less and less habitat area each year (Wildearthguardians.org)..

Their historical range has been described as wetland areas along the Sangre de Cristo Mountains in CO and NM, the San Juan Mountains in CO, the Jemez and Sacramento Mountains in NM, the Rio Grande Valley in NM, and the White Mountains in AZ. Their current numbers consist of 115 specific localities (mostly documented by museum research) spanning across six ecoregions and eight management areas that are meant to encompass this historic range (USGS.gov). On April 15, 2016, U.S. Fish and Wildlife designated 13,970 acres of critical habitat for the mice over five counties within New Mexico, three in Colorado, and two in Arizona. This encompasses 170 miles of streams that will be managed with federal agency assistance (FWS.gov, 2016).

Important questions that need answers from fundamental research at natural history museums:

• Have all populations of the NMMJM been detected?
• How distinctive are each of the isolated populations of the NMMJM?
• Do populations regularly exchange individuals or are they permanently isolated?
• Is there evidence of genetic erosion due to persistently small population sizes?
• Is the NMMJM a distinct species (Zapus luteus) as some have suggested?
• What is the biogeographic history (when and how they got to isolated locations) of the NMMJM?

Permanent sample archives in museums are key to effective management initiatives, both in the short-term and long-term. They provide key insights into taxonomic classification, levels of differentiation and exchange between populations, occurrence of pathogens and pollutants, and other aspects of basic biology such as local extirpation. Until very recently, most evolutionary trees were based on morphological characteristics, but recent technological developments allow genetic and even genome-scale data generated from museum samples to more rigorously characterize relationships and other evolutionary measures such as adaptation to local conditions. DNA that has been preserved within museums can be used to look at genetic similarities and differences that might mark important factors that have led to isolation and divergence.

In comparing taxonomy-based and discovery-based approaches to gather North American jumping mice (subfamily Zapodidae) data, phylogeographic tests resulted in different species-level classification. Tests of 4-species, 28-lineage, and 15-species hypotheses using both evolutionary and ecological analyses confirmed divergence among at least eleven groups that could be deemed species. If additional tests are able to uphold those findings, taxonomic revision will have to occur to this clade of animals and conservation plans will need to be updated across the western US (Malaney et al., 2017).

More broadly, because natural history museums preserve holistic specimens (saving and curating multiple parts), they provide novel insights unattainable using mark-recapture or other observation-only techniques. Furthermore, as new technologies become available, new, previously unimaginable tests can be used to investigate historical conditions through these specimens. Museums specimens can be returned to repeatedly to extend research and validate previous work – hallmarks of high-quality science. Novel insights include (but are not limited to):

• Presence/absence and population turnover at specific localities
• Evolutionary relationships and taxonomy
• Biogeographic history (e.g., how, when populations were isolated or colonized)
• Interactions (e.g., gene flow) among neighboring populations
• Changes in DNA variability through time (e.g., genetic erosion)
• Ecological associations: habitat relationships, ecological niche
• Interactions with other species in the community and community turnover
• Stable isotope ecology and food webs (you are what you eat)
• Presence/absence and intensity of parasites and pathogens including emerging infections
• Bioaccumulation of toxins such as heavy metals, PFAS, and other pollutants
• Morphological differences or developmental in individuals, populations, & species
• Traits of species – e.g., offspring number, kidney size/structure, intestinal length
• Diet analyses
• Many, many others especially with new technology

Proposed taxonomy and evolutionary relationships for North American jumping mice, which includes 11 species (colored boxes) that began diversifying during the Pliocene (4.6 MYA). Below are major geologic epics with shading corresponding to dominant glacial-interglacial periods (light and dark respectively) throughout the Pliocene (blue), Pleistocene (grey), and Holocene (black). Note that Z. hudsonius and Z. luteus (green and brown boxes respectively) are the most recent groups to diverge, meaning that all of the other species present belong to lineages that arose earlier in ecological time. They carry deeper historical cell lines that are more important to protect and conserve (Malaney et al., 2017).