Monarch Monitoring Results

 Here's a cool synthesis paper using data from the Integrated Monarch Monitoring Program (IMMP).  The headline conclusion is that ROWs had the most milkweed plants:

Site Type: ACL, Agricultural Conservation Land; DEV, Developed; PGS, Protected Grassland; ROW, Rights-of-way; UGS, Unclassified Grassland. 

However, this paper excludes Asclepias subverticillata (and A. verticillata), the most common milkweed species in our area.  Apparently this was so they could apply their total stems to the work of Thogmarten et al that calculated how many stems of milkweed are needed to support stable monarch butterfly populations.  But, since the main results of this paper compare milkweed plants between different site and habitat types, they should at least show what this analysis would look like with A. subverticillata.  

Actually, most of the paper's results are focused on Eastern U.S., and there is a companion Western paper forthcoming, but that is not obvious from the Abstract.  So excluding a common western milkweed plant may not have changed most of the results.  

What's also not obvious is that none of the figures show actual data, they only show the model results derived from the data.  Apparently that is how ecology works now-a-days:  create some kind of bespoke complicated statistical model and don't even bother to plot the underlying messy real-world data...

Citation

Front. Ecol. Evol., 23 May 2024

Sec. Conservation and Restoration Ecology

Volume 12 - 2024 | https://doi.org/10.3389/fevo.2024.1330583

Mapping Species Habitat with Appropriate-Sized Buffers

 Previously, I wrote that this Story Map shows small polygons of habitat as buffers around representative observations.  However, the actual locations are not accurate because the underlying observation data has been randomized to protect populations of rare species. 

The first map ("Preliminary Conservation Zones" and "Potential Dispersal Zones" for the American, Rusty-patched, Suckley's, and Western bumble bees) shows the correct kind of critical habitat (buffered observations) USFWS has designated for rusty patch and would likely designate for other proposed species, but the locations are incorrect.  For example, the mapped locations of Rusty patch on that map do not line up to the USFWS GIS for rusty patch critical habitat. 

 

Some of the other species may be are incorrect as well, depending on whether the data source (GBIF) considers the species endangered and so randomized the locations within a 0.2 degree lat/long box.  That seems to be the case for the Western Bumble bee, but not the American bumble bee. 

 

The map shows a mix of accurate and inaccurate, specific habitat points. This is confusing and potentially misleading, if the intent is to facilitate conservation planning.  For example, when I zoom to an area of interest, I might think there is no mapped habitat there. But if there is some nearby, I can't tell from if that habitat is or isn’t within my area of interest.

 

The easiest fix would be to increase the size of the buffers so that they include the entire randomized area (0.2 degree, lat/long) that each point comes from.  A note could say that critical habitat would likely be designated in a subset of those larger polygons based on the buffer size USFWS decides.

Rusty Patched Bumble Bee Critical Habitat

Rusty patched bumble bee range map.

USFWS listed the rusty patched bumble bee (Bombus affinis) as Endangered in 2017 due to a marked decrease in the range and size of populations across the Eastern U.S.  

As one of the first insect species to be listed under the Endangered Species Act, it offers an interesting case study for the way USFWS may approach other insects proposed for listing, including the Monarch butterfly, and numerous other bumble bee species.

From Xerces Society Listing Petition, 2016.

The listing petition states that "the rusty patched bumble bee probably needs floral resources to be located in relative close proximity to its nest sites, as studies of other bumble bee species indicate that they routinely forage within less than one kilometer from their nests ... although in some cases nearly two kilometers ... [It] is likely dependent upon woodland spring ephemeral flowers, since this bumble bee emerges early in the year and is associated with woodland habitats.....Rusty patched bumble bee queens are one of the earliest species to emerge, with observations as early as March and April."

Interestingly, rather than designate critical habitat based on the habitat needs of the species, USFWS chose to designate "High Potential" zones (e.g. critical habitat) as 1 mile buffers, and "Low Potential" zones as 4 mile buffers, around known (since 2006) sightings of the rusty patched bumble bee:

USFWS Map showing "High Potential" and "Low Potential" zones.  

Detail showing example 2x2 mile rusty patched bumble bee "High Priority" habitat in DeKalb, IL from USFWS map.  The buffered area seems to be based on a sighting at Prairie Park, and includes residential and industrial developments.  The only habitat in the area is within Prairie Park.  

USFWS has issued the guidance on whether consultation is required.  For vegetation management activities within the High Potential zones, the guidance provides the following test questions:

• Is there habitat for nesting, foraging, and/or overwintering for the rusty patched bumble bee in the action area or will the proposed action restore habitat for the species in the action area? 

• Will the action cause effects to vegetation in rusty patched bumble bee habitat in the High Potential Zone during the nesting period? Effects could occur as a result of mowing, cutting, grazing, prescribed fire, tree removal, spot-application of herbicide, tree clearing, and/or other activities. 

Based on this case example, it seems likely that USFWS will take a similar approach when listing other bumble bee species.  Specifically, it seems likely USFWS will only designate habitat immediately surrounding recently documented sightings, as opposed to using a general habitat model across the species' range.  Then, Section 7 consultation will be required for any activities that disturb habitat during the nesting period (i.e. growing season).

This seems to be the assumption underlying this Story Map, which shows small polygons of habitat as buffers around representative observations.  Note that the actual locations in this map are not accurate because the underlying observation data has been randomized to protect populations of rare species. 

This map of rusty patched bumble bee habitat around DeKalb, IL schematically shows the kind of habitat USFWS designated (i.e. buffered polygons around point observations) but does not show the accurate locations of the habitat because the data used for the map (GBIF) is randomized within 0.2 by 0.2 latitude/longitude rectangles.  

A streamlined, GIS version of USDA's Environmental Benefits Index

USDA calculates the environmental benefits of applying conservation easements to farmland.  The University of Minnesota has developed an online tool for mapping three important components used by decision-makers to prioritize farmland conservation funding:

Soil loss is calculated using the Universal Soil Loss Equation, which factors in slope angle and distance, soil texture,

Water quality risk was calculated using a Stream Power Index, and proximity of land parcels to streams.

Habitat quality was calculated using by intersecting known stressors such as roads and development with known areas of high quality habitat, such as areas with endemic or endangered species, high biodiversity, and/or high game abundance.

The combined metric for all three layers generates the Environmental Benefits Index.

Screenshot from maptool from the EBI page of the Natural Resources Research Institute at the University of Minnesota.