More on NM Rare Plant Communities #nmpcomm

The New Mexico Rare Plant Technical Council just lost their chairperson, Daniela Roth, to other profession opportunities. She was a tireless advocate for NM's natural environment and especially its rare plants. Although Daniela worked for the NM State Forestry Division, she is recommending that her replacement(s) be in the NM Natural Heritage Program. That leads me to this edition of my on-going monthly essays on NM rare plant communities with a stroll through the Natural Heritage online maps (https://nhnm.unm.edu/).

Our first map today is of the US Forest Service Research Natural Areas in AZ and NM. These are selected areas that are conserved for long-term research. An accompanying spreadsheet (https://nhnm.unm.edu/sites/default/files/nonsensitive/USFS%20RNA%20Overview.xlsx) gives details on each of the 52 RNA's and gives one a good idea of the amount of fieldwork and thought that goes into choosing these areas as part of a southwestern environmental monitoring network.

The website goes on the say, “...work is ongoing to expand it to include other protected natural areas such as Areas of Critical Environmental Concern (ACECs), refuges, and preserves. We invite you to explore information about network sites through the ArcGIS Viewer, consider doing work on them for research and protection, and to suggest sites that should be added to the network.”

Sounds like an invitation for some serious citizen science.

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The remainder of today's maps are generated with the NM Environmental Review Tool (https://nmert.org/content/map) with its many layers of information. Layers can be toggled on or off to overlay whatever features you desire. My examples make use of only one or two layers at a time for simplicity.

Our second map is of NM State Forestry's Priority Landscapes. These are areas identified for restoration across all jurisdictions with forest and woodland cover types and maps the top 500 watersheds in the state ranked by wildfire risk and importance for water source protection and biodiversity. There are some odd features here and there, like the odd boundaries in the southern Jemez, but I assume these are more administrative lines than anything else.

Map #3 is the US Fish and Wildlife Service refuges and critical habitat. No surprises here, although many people don't realize how big the Sevilleta Refuge is. It runs from the Sierra Ladrones almost over to Abo.

Map #4 is a slice of the crucial habitat layer (somehow different from "critical habitat"). When looking at this data for the entire state, the map is a difficult to understand set of blue blotches. Zooming in gets you to the meat of the matter. The sample I included here runs from an area surrounding Voght Draw in the west to the southern Jemez Mountains in the east. The map legend shows six shades of blue running from pale to dark, least to most crucial habitat. Lots of small pockets of deeper blue out by White Mesa, Cuchilla Blanca Hill, southwest of San Luis in the Rio Puerco, and Tapia Canon further south. I'd say those are great places to go plant hunting. While some are very remote, others are right off the pavement.

The last map I want to share today explains much about why native plant conservation is difficult in NM. This one shows land ownership and NM is a crazy quilt of federal and state administrations interspersed with private lands. With so many administrative units and so many definitions of what is crucial or critcal habitat, what is a threatened, endangered, or rare plant, it's no wonder that delimiting important areas is a Sisyphean task.

Plant Diversity

Part of my reason for posting these monthly essays on NM plant communities was to get my own mind wrapped around the problem of where should we be putting our efforts, both time and money, into conservation. It's one thing to look at the individual rare plants listed at https://nmrareplants.unm.edu/ and another thing all together to look at them in terms of their ecological contributions. In turn, where can I as an individual make an impact?

Biodiversity is a critical part of sustainable development. A vibrant, diverse, and healthy environment provides everything from harvestable resources, nature tourism, wild genes to improve domestic crops, pest management, sources of medicine, and biologically-based environmental clean-up (https://doi.org/10.1098/rstb.1994.0089). Sustainable development and the maintenance or enhancement of biodiversity relates in little-explored ways to ecosystem function, stability and resilience.

The draft UN convention on biological diversity (CBD) sets out biodiversity targets for the end of the decade that include protecting 30% of land and sea, eliminating billions of dollars of environmentally harmful government subsidies, and restoring at least a fifth of degraded freshwater, marine and terrestrial ecosystems. The final version will be negotiated in Kunming, China, at the Cop15 summit, which is expected to be held at the end of August (2022). The CBD balances three main goals: conservation, sustainable use of biodiversity, and the fair sharing of benefits from genetic resources.

As I write this (3/28/22), BBC has published a primer on biodiversity at https://www.bbc.com/news/explainers-60823267. Without getting too deep in the weeds, they illustrate the key issues in five graphics. They define biodiversity as the variety of all life on Earth. It turns out, it's not that simple.

So what is biological diversity, that is, biodiversity? These essays on ecological regions, life zones, and community evolution with a focus on New Mexico have been using the term without formal definition.

For most people, biodiversity is simply the number of species in an area, which in the older ecological literature was called “species richness.” In a seminal paper by Harper and Hawksworth in 1994 (https://royalsocietypublishing.org/toc/rstb1990/1994/345/1311), only six years after Elliot Norse gave the term a proper definition in the literature, some important questions were raised: What is ‘biodiversity’? Is biodiversity just the number of species in an area? If biodiversity is more than the number of species how can it be measured? Are all species of equal weight? Should biodiversity measures include infraspecific genetic variance? Do some species contribute more than others to the biodiversity of an area? Are there useful indicators of areas where biodiversity is high?

Let's run through some of these...

A little reflection will show us that the number of species in an area isn't of much use, even though at first blush one might think otherwise. Because we tend to emphasis organisms that are visually obvious to us, we think of a landscape that is biodiverse as one with lots of differences at the macroscopic level.

But imagine an island with exactly two organisms. Are the following pairs all equally biodiverse?

• A 'Gala' apple tree and a 'Honey Crisp' apple tree (different cultivars)

• An apple tree and a rose (different genera in the same family)

• An apple tree and a grass (different phyla)

• An apple tree and a mouse (different kingdoms)

Obviously, a measure of biodiversity should take into account how different the various organisms are. A metric that uses increasing phylogenetic divergence or number of taxa or genetic variability might seem attractive but there are problems that for now we'll dismiss with a wave of the hand.

It would be handy to include some measure of infraspecific biodiversity in a particular location or population. At the BioPark Zoo, there are species survival plans (SSP's) for animals that take into account genetic relationships among a species across all collections at all accredited zoos to avoid inbreeding. Only recently have I read discussions about taking care to maintain genetic diversity among living collections in botanic gardens and arboretums.

Particularly worrisome in a world being fed increasingly by monocultures is the loss of genetic diversity in crops. One of the IUCN specialists at the BioPark recently gave a fascinating webinar on diversity or the lack thereof among apples and crab apples. Similarly, the NY Botanical Garden had a webinar on crop wild relatives with much the same message: we need wild species as genetic backstops for future agricultural improvements.

From my own experience as a horticulture postdoc at NMSU, we had assembled a large collection of onion genera in order to find genes for disease-resistance. Another professor collected field races of chiles in order to capture the variability within the species. In either case, the economic importance of the crops made the argument for conserving diversity.

But economic importance isn't the only metric for determining which aspects of biodiversity are “worth” conserving. We need the natural environment outside of agricultural production for a host of reasons ranging from recreation to climate moderation.

Turning our attention back to NM, Natural Heritage New Mexico out of the Museum of Southwestern Biology and Dept. of Biology at UNM have come up with a methodology for estimating biodiversity in areas of the state. Their biodiversity score (scale of 1 to 10) is an average of the scores for three factors: size, quality, and landscape integrity. The landscape integrity score is down-weighted by 50% to account for uncertainty in the accuracy of that layer.

Like our NY Times maps, NHNM used NatureServe maps where possible to generate Element Occurrences that defined populations of species of interest. Using some slick GIS tricks, this allowed them to generate Element Occurrence polygons that grouped populations together into areas of interest where their scoring methods could be applied.

One result is a map of NM that ranks areas of biodiversity. (I've slightly modified their color-coding to minimize the optically biased effect produced by their strong yellow color for moderate biodiversity. Instead, I've made 'Moderate' the palest color instead of the brightest.) The polygons are Important Plant Areas (IPA) and ranked by their Biodiversity Rank and Diversity Score. There are 150 IPA's in NM.

Within an hour's drive of Albuquerque, we find these IPA's:

23^* Espanola to La Cienega

34^* White Mesa

35 Lower Jemez River Valley

36 Espinosa Ridge

42 Rio Puerco / Rio San Jose

43 KAFB

44^* Sandia Mtns

45 South Mtn

55 Rio Grande at Belen

56 Sevilleta Basin

142 Socorro and Strawberry Peaks

*Indicates IPA with outstanding biodiversity rank.