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

Rare Plants and High Quality Ecosystems Mapped in Washington State

 The new HDMS mapper from WNHP shows rare plants as well as Ecological Integrity Assessments (EIAs) for a wide range of ecosystems.

For example, here are the rare plant areas East of Renton:

And here are the natural ecosystems with an "A" rating:

Phenology, Accumulated Growing Degree Days, and Soil Moisture

US Crop Calendar

Source: https://ipad.fas.usda.gov/countrysummary/Default.aspx?id=US

Arizona had a good year for NDVI

Source: https://glam1.gsfc.nasa.gov/

NASA SMAP data.  Data is global.

This mapped layer is delayed by 2 weeks.  I haven't found a layer that shows real-time moisture.

NPN Visualization tool can view Historical, Current, and Anomaly Accumulated Growing Degree Days. Data is only for USA.

Source: https://data.usanpn.org/vis-tool/#/explore-phenological-findings

Restoration in hyper-arid environments?

 Is is possible to plant trees and restore grassland savanna in a hyper-arid desert?  

In Al Baydha it sometimes doesn't rain for 26 months, and apparently there are trees that can survive and thrive in that environment.

The Story of Al Baydha: A Regenerative Agriculture in the Saudi Desert.

Missing Mammals?

 Animal population distributions can be assessed using iNaturalist.  The website is used by citizen scientists to report animal and plant observations.  Rare animals may not be mapped well, but my hypothesis is that large mammals are well mapped because humans tend to make note of them.  This may be less true for nocturnal animals, and it also depends on the presence of humans.

Raccoon observation from iNaturalist.

The map above of raccoons and the map below of coyote observations shows that both species are well-distributed across the U.S.  Clusters of observations are probably more likely due to sampling bias around large cities rather than actual differences in population density. 

Therefore, these maps can show overall distribution but may not be as useful for determining densities.

Coyote observations from iNaturalist.

The next map shows that moles do not occur in the central arid and mountainous part of the U.S.  It appears that these animals need mesic conditions and rich soil.

Mole (family) observations from iNaturalist.

In contrast, Pocket Gophers, a similar group of burrowing animals, are found throughout the arid West as well as along the Pacific coast and in Florida.

Pocket Gophers

But another burrowing mammal, the Prairie Dog, is restricted to the arid West:

Prairie Dogs

While the Prairie Dog distribution makes sense at the continental scale, zooming in reveals interesting patterns.  In northern AZ, Prairie Dogs are mainly restricted to the I-40 corridor, despite extensive grassland habitat in, for example, the Chino and Prescott valley area. The data for this zoomed-in view is much sparser than the national map and it is likely that there are many areas with missing observations. 

However, I am confident that any highly-visible Prairie Dog colonies in the Prescott area would have been photographed at some point.  Given the presence of suitable habitat surrounding occupied habitat in AZ, it may be that Prairie Dogs populations have been extirpated and fragmented across northern AZ.

Prairie Dog observations in northern AZ.

Each of the above species distributions can be related to environmental variables, but other mammal distributions are more complex.  Porcupines feed on the growing tips of conifer and deciduous trees, but apparently do not occur in much of the Midwest and southeastern parts of the U.S.  I'm not sure why this would be, as there is plenty of what looks like suitable habitat in these regions, and the presence of the species in the southwest and the northeast spans a large environmental gradient.

Porcupine distribution

Porcupine observations are quite scattered across much of the West, despite the fact that they are fairly visible in trees; birders looking for birds would be very likely to see them. There are large areas of suitable habitat in AZ, for example along the Verde river in Cottonwood.  I'm not sure why this species hasn't been observed anywhere on the Verde river.  Perhaps it has been extirpated from these areas.  Or, the two observations around Prescott may have been of dispersing animals and the population is only reproducing in the higher elevations around Flagstaff.

Porcupines in northern AZ.

Badgers also show a predominantly Western and great-plains distribution.  They need large areas of open space.

Badger distribution

However, in Northern AZ few animals have been observed.  This nocturnal burrowing animal may simply escape frequent detection, or it may be very infrequent on the landscape.  Supporting the idea that humans rarely encounter this animal, many of these observations are road kill.  Interestingly, badgers are found in AZ both in high-elevation mountain habitats and in low-elevation Sonoran desert habitat!

Badgers observations in AZ.

 Another animal with a strange distribution is the Opossum.  It seems to avoid most of the interior arid West, except for southern AZ.  The observations in Tucson would seem to be environmental outliers compared to the populations along the West coast and in the Eastern U.S.

Opossum distribution.  

Much can be learned by studying species distributions and noting where animals have been observed as well as where they have not.  Trying to explain the observed distributions raises many questions. The mysteries surrounding animal distributions are fertile ground for theorizing about animal behavior, history, and habitat needs.

Australian Wildfires

Extremely large pyrocumulus clouds tower over bushfires in New South Wales and spread over the Pacific Ocean. Sentinel-2A image, December 31, 2019, processed by @andrewmiskelly.  Source.

A pyrocumulus cloud is produced by the intense heating of the air over a fire. This induces convection, which causes the air mass to rise to a point of stability, where condensation occurs. If the fire is large enough, the cloud may continue to grow, becoming a cumulonimbus flammagenitus which may produce lightning and start another fire.  Source.

"Fuels management cannot prevent fires but can change their behavior" but fuels management is limited by budgets and time to burn, especially in droughts." Source.

The BBC has a good overview:

"We’re seeing recurrent fires in tall, wet eucalypt forests, which normally only burn very rarely. A swamp dried out near Port Macquarie, and organic sediments in the ground caught on fire. When you drop the water table, the soil is so rich in organic matter it will burn. We’ve seen swamps burning all around."

"Even Australia’s fire-adapted forest ecosystems are struggling because they are facing increasingly frequent events. In Tasmania, over the past few years we have seen environments burning that historically see fires very rarely, perhaps every 1000 years. The increasing tempo, spatial scale, and frequency of fires could see ecosystems extinguished." Source.


More Info.
Australian Fire Center
Case Study / Educational Info

Plant Interactions Versus Integrated Vegetation Management (IVM)

Questions:  does existing vegetation help or hurt the IVM goal of creating a self-sustaining, compatible plant community?  Do some compatible species tend to facilitate or inhibit the establishment and growth of incompatible species? And do these plant interactions vary systematically across ecosystems?

These questions fall into the domain of “Community Ecology”.  This looks like a good review paper but I don’t have access to it.  Ecology is notoriously unsystematic, so (without reading the review) I bet the answer is “Its complicated” and “It depends.”

Here are some papers I was able to access:

Paper: The role of plant interactions in the restoration of degraded ecosystems: a meta‐analysis across life‐forms and ecosystems

Link: https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/j.1365-2745.2009.01573.x

Relevant Conclusions:  Inhibition predominates in herbaceous communities typical of early‐successional stages, whereas facilitation prevails in communities dominated by shrubs and trees.

My Comment: IVM that leaves shrubs (like in Sonoran desert) would probably not create inhibition for tree growth, whereas IVM that leaves grasses (like Ponderosa habitats) would be expected to inhibit tree growth.

Paper: Is the change of plant–plant interactions with abiotic stress predictable? A meta‐analysis of field results in arid environments

Link: https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/j.1365-2745.2005.01017.x

Relevant Conclusions:  Density data showed that the net effect of plant neighbours was positive at low abiotic stress and negative at high abiotic stress levels.  However, none of our meta‐analyses indicated that the magnitude of the net effect provided by plant neighbours, whether positive or negative, was higher under high abiotic stress conditions, and facilitation does not therefore appear to increase in importance with abiotic stress.

My Comment: Results are mixed, but in general deserts do not show more importance of “nurse plant” facilitation.

Ecosystem Art

I've previously blogged about cool ecosystem artwork, and wanted to recognize more amazing artists in this post.

The Nature of America stamp series featured the ecosystem artwork of John D. Dawson.

Dawson is one of the best-known artists featured in National Park ecosystem artwork, such as these brochures from Olympic National Park.

Larry Eifert may have done more ecosystem artwork for the NPS than any other artist.

The USFS has a series of posters featuring the ecosystem artwork of Steve Buchanan.

A model of Ecosystem Monitoring to inform Adaptive Management

From:
Lininger, Jay.  2006. Effectiveness of Stand-Scale Forest Restoration in the Siskyou Mountains, Oregon.

Roadsides Provide Critical Habitat for Pollinators

"Over the past 18 months, support for pollinators has undergone a seismic shift, led by President Obama, who called for a national Pollinator Task Force in the spring of 2014. Less than a year later, in a book-length "Strategy to Protect the Health of Honey Bees and Other Pollinators," the federal government set ambitious goals that include the restoration or enhancement of 7 million acres of land for pollinator habitat over the next five years. Roadsides will comprise a significant portion of that acreage..."
Read the rest of the article.

Threatened and Endangered Species of the Williamette Valley Prairie Savannas

There are 6 listed species endemic to the ecoregion.

Fender's Blue butterfly (E) (Icaricia icarioides fenderi)
Willamette daisy (E) (Erigeron decumbens var. decumbens)
Bradshaw's desert-parsley (E) (Lomatium bradshawii)
Kincaid's Lupine (T) (Lupinus sulphureus ssp. kincaidii)
Nelson's checker-mallow (T) (Sidalcea nelsoniana)
Golden Paintbrush (T) (Castilleja levisecta) - extirpated from Williamette valley

Several other nonlisted species are also considered sensitive:

Taylor’s (whulge) checkerspot butterfly, Euphydryas editha taylori
Pale larkspur, Delphinium leucophaeum
Willamette Valley larkspur, Delphinium oreganum
Peacock larkspur, Delphinium pavonaceum
Shaggy horkelia, Horkelia congesta ssp. congesta
White-topped aster, Sericocarpus rigidus
Hitchcock’s blue-eyed grass, Sisyrinchium hitchcockii

There are two major rare habitats in the Williamette valley responsible for the listed and sensitive species: upland prairies and wet prairies. Prairies are dependent on disturbance to prevent succession, and many have been either plowed under or allowed to develop into forests or shrublands.  A recovery plan extends throughout the Williamette valley, and south of Roseburg to the Douglas county line to include a third disjunct habitat in the Umpqua valley.  

The plant composition of upland prairies is dominated by bunchgrasses, including Festuca idahoensis, Danthonia californica, Elymus glaucus, Achnatherum lemmonii, and Koeleria macrantha.  The spaces between the bunchgrasses are typically covered by mosses, fruticose lichens, or native forbs. Showy, slow-growing perennial forbs include Eriophyllum lanatum, Potentilla gracilis, Fragaria virginiana, Sidalcea malviflora, and Symphotrichum (=Aster) hallii, and the bulbs Calochortus tolmiei and Dichelostemma congestum. Some fast-growing annual forbs, including various species of tarweed (Madia spp.) and Clarkia, are also prominent members   The main threat are vegetatively spreading non native grasses included Agrostis, Festuca, as well as Rubus (blackberry).

Wet praries are dominated by herbs. Deschampsia cespitosa (tufted hairgrass),and tufted microhabitats. Non-native Agrostis and Cirsiums are threat.

Cultivating a Healthy Skin Microbiome

A company is marketing a probiotic spray designed to help cultivate a healthy skin microbiome.  The spray contains Ammonium Oxidizing Bacteria (AOB; specifically the genus Nitrosomonas) that derive their energy solely from consuming the ammonia and urea found in sweat.  Supposedly, if you have enough AOB, you don't smell bad because they consume all your sweat, releasing beneficial nitric oxide gas!



I wanted to learn more about the skin microbiome, and found this comprehensive article with diagrams to show skin follicles, etc the complex topography and ecology of the skin environment.

These new data are based on DNA assays, and with improvements to these techniques, viruses, mites, and fungi are also being inventoried. This is certainly an improvement from the old days when only culturable bacteria were studied.  Here is a classic paper about the microbial correlates of dandruff.  Apparently there is no cause of dandruff, but simply a feedback between bacteria and fungi and the scalp. A fungus called Malassezia spp can release compounds that stimulate epidermis to proliferate.    Fungicides cure dandruff by killing the Malassezia spp, but many people harbor Malassezia spp without dandruff.   Perhaps an "ecological" cure could involve cultivating probiotic bacteria?

The same article also has the classic diagram showing different microbial communities on different body parts, based on their temperature, moisture and oilyness (sebum versus apocrine ).

Interestingly, soap and shampoo may be destabalizing our skin microbiome, in the same way that antibiotics can impact the gut microbiome.  For example, many ingredients in personal care products have been found in laboratory tests to inhibit "good-guy" AOBs, including sodium lauryl sulfate (SLS is one of the harshest detergents), sodium coco-sulfate, and even castile-type soaps. (Source)

To maximize ammonia utilization, AOBsproduce unique enzymes on elaborately folded cell membranes. These membranes are intricately folded so that they can increase the surface area for ammonia-oxidation. This means that they are able to boost both their ammonia-oxidizing capacity and their energy output.  However, this elaborate membrane architecture also renders AOBs particularly sensitive to membrane-disrupting chemicals, such as anionic surfactants found in modern soaps and detergents.

Detergents replaced simple soap in our hygiene routine soon after WWII and form a major part of most bath products. Anionic detergents such as lauryl sulphates, sarcosines and sulfosuccinates can be harsh to the skin and especially the microbiome.

When reading the ingredients list on your cleaning products, you can identify anionic surfactants as those that have the following in their names:

Sodium
Ammonium
Magnesium
Sulfate
Sulfonate
Gluconate

(For example, sodium laurel sarcosinate, magnesium laurel sulfate, and sodium gluconate.)

Nonionic surfactants are gentler to the skin microbiome, although not entirely harmless. (Source) They include:

Ethoxylates
Alkoxylates
Cocamide

All of my soaps and shampoos contain these ingredients, except for Black African soap "made from shea butter and palm kernel oil mixed with ashes".  The detergent in this soap is laurel glucoside, (AKA dodecyl glucoside) a non-ionic surfactant molecule.  Because it is non-ionic, it is a milder detergent, often used in cosmetics, shampoos, etc. Glycosides are produced from lauryl alcohol and glucose.

It may be possible to specially order detergents from companies like this one.  

The Theory and the Reality of Shelterbelt Afforestation Projects

The Theory of Shelterbelts

The Reality

Introduction:  dust bowl, us efforts

Following the dust bowl years in the U.S. the government planted 220 million trees in a strip 100 miles wide, stretching 18,600 miles from Canada to the Brazos river.  1935-1942  Today, the growth and vigor of many trees has declined due to close spacing, age, and invasion of undesirable short-lived trees.  Wikipedia.

There are currently two major afforestation programs, one in China, and one in the Sahel.

Great Green Wall in China. 

This project aims to afforest 90 million hectares and eventually contain 100 billion trees in a 4500km belt.

A recent paper by Tan (2014) found decreased dust transport due to the plantings so far.  But independent Chinese media reported in 2013 that dust storms were increasing:  For centuries in northern China, annual sandstorms, called the Yellow Dragon, have been ripping through the city.  Wind erosion is obvious and most pronounced in spring, when sandstorms are common and the vegetation is still absent or dormant after severe winter temperatures. Sandstorms have increased in the last few years, calling into question whether the Great Green Wall is working.

Liu Tuo, head of the desertification control office in the state forestry administration, is of the opinion that there are huge gaps in the country's efforts to reclaim the land that has become desert. At present there are around 1.73 million sq kilometers that have become desert in China, of which 530,000 km2 are treatable. But at the present rate of treating 1,717 km2 per year, it would take 300 years to reclaim the land that has become desert.  

Background
In early times, Korqin was not a semi-desert, but savannah-type woodland, in transition between dense forest and the steppe zone. The rolling sand-sheet was deposited during the last glacial period (12000 years BP). During 10,000 years of vegetation growth, thick dark topsoil developed. Since historical times, the region has gone through several cycles of man-induced desertification and subsequent recovery, when human pressure lessened. Fertile dark topsoil vanished and extensive dune fields gradually build up.  Overgrazing (by cattle, goats, sheep, camels, horses), clearing of land for agriculture and over-cutting of trees and shrubs in this vulnerable ecosystem have resulted in an increasingly severe land degradation and desertification.

Other Approaches?

There are many who do not believe the Green Wall is an appropriate solution to China’s desertification problems. Gao Yuchuan, the Forest Bureau head of Jingbian County, Shanxi, stated that “planting for 10 years is not as good as enclosure for one year,” referring to the alternative non-invasive restoration technique that fences off (encloses) a degraded area for two years to allow the land to restore itself.  Soil fertility, already critically low, has shown a sharp decline as all organic residues from crops are removed for fuel and fodder during wintertime. Willow and poplar stands are pollarded in autumn, before leaf fall, for the same purpose. The continuous removal of potential nutrients to the soil is not balanced by the relatively small amounts of manure and inorganic fertiliser applied to crops.

Problems

 Jiang Gaoming, an ecologist from the Chinese Academy of Sciences and proponent of enclosure, says that “planting trees in arid and semi-arid land violates [ecological] principles”.The worry is that the fragile land cannot support such massive, forced growth. Tree growth in Korqin is largely dependent on the presence of a high groundwater table, fed by percolation and inflow from the western and southern mountainous areas. The long-term trend of a decreasing depth of the groundwater table is due to an increasing demand for water to irrigate crops and for human and industrial needs. If the trees succeed in taking root, they could soak up large amounts of groundwater, which would be extremely problematic for arid regions like northern China.  For example, in Minqin, an area in north-western China, studies showed that groundwater levels have dropped by 12–19 metres since the advent of the project.

Progress So Far

As of 2009 China’s planted forest covered more than 500,000 square kilometers (increasing tree cover from 12% to 18%) – the largest artificial forest in the world.However, of the 53,000 hectares planted that year, a quarter died. In 2008 winter storms destroyed 10% of the new forest stock, causing the World Bank to advise China to focus more on quality rather than quantity in its stock species.  FAO report

But the program’s widespread tree planting campaigns typically allot only one or two species of tree to an area. Professor Jiang wrote in a 2009 Epoch Times article, “In Ningxia, for example, 70 percent of the trees planted were poplar and willow. In 2000, one billion poplar trees were lost to a disease (Anoplophora), wiping out 20 years of planting efforts.”  FAO report followup

More criticisms:  Wikipedia.

Great Green Wall in Africa - the Sahel

The Great Green Wall initiative is much more nuanced than simply planting a belt of trees across the continent: “Behind the name or the brand ‘Great Green Wall,’ different people see different things. Some people saw just a stripe of trees from east to west, but that has never been our vision,” he says. “In Niger, Mali, and Burkina Faso . . . natural regeneration managed by farmers has yielded great results. We want to replicate and scale up these achievements across the region. It’s very possible to restore trees to a landscape and to restore agroforestry practices without planting any trees. This is also a sustainable way of regenerating agroforestry and parkland.”

But it should be noted that the Great Green Wall is not designed to prevent the Sahara Desert from expanding. “We are not fighting the desert,” he says. “In the majority of the areas we are working in these 11 countries, the desert is not advancing. The [Sahara] Desert is a very stable ecosystem. Of course, there are some areas on the margins—for instance in Senegal, Mauritania, and Nigeria—where there are some sand movements. But from a geographic perspective, over time the desert has been relatively stable in this area.” (Source)

But some authors advocate  "a shift from planting trees in the GGW to utilizing shrubs (e.g., Leptospermum scoparium, Boscia senegalensis, Grewia flava, Euclea undulata or Diospyros lycioides), which would have multiple benefits, including having a faster growth rate and proving the basis for silvo-pastoral livelihoods based on bee-keeping and honey production.” (Connors and Ford, 2014 Sustainability)

Fence Line Contrasts

Sitting on the fence has become a metaphor for ambivalence, but actual fence lines are some of the clearest lessons in land management.  Fencelines can be the best place to study ecology, because most fences divide two different land management histories.  The easiest places to learn from fence line contrasts is where the land management history is known.  For example, along highway right-of-ways (ROWs), the strip of land between the road and the fence is almost never grazed, whereas the private or public alotment on the other side of the fence has almost certainly been grazed and/or farmed.

However, just because the ROW hasn't been grazed doesn't mean that it has escaped disturbance. While comparing two disturbed areas can yield some insights, the multiple factors at work will make cause and effect deductions extremely difficult. To find a good comparison, look for areas that are relatively far from the road; immediately adjacent to the road is a zone of disturbance, which can include vehicle traffic, trash, mowing, and runoff from the road (i.e. increased moisture).

The best comparison areas occur where the ROW is relatively higher than road (so there is no possibility of runoff and little chance of other human disturbance).  However, areas with cutbanks below them are not good for comparisons, because of excess erosion, different microclimates around bare rock or exposed subsoil, and lowered water table.   A zone of depression in soil moisture can also occur around ditches, trenches, gullies, roadcuts, etc.

The actual fence-line itself may have different species due to fence-line drip of dew and the ability of fences to catch seeds, especially tumbleweeds. (photo).

On the ground immediately beyond the fence there may be an area of extra disturbance due to cattle trails, etc, and any areas near stock tanks or gates are also likely more heavily used (and hence a more extreme contrast).  In cases with less grazing on the private land, such as on steep hill slopes, vegetation and soils may look quite similar across fence-lines.  Of course, there will always be variable disturbance on both sides of the fence, but that is part of the challenge and opportunity of observing fence-line contrasts.

The best comparisons are between areas relatively far from disturbance, close to but not immediately adjacent to the fence-line.  With a good undisturbed ROW as a control, the vegetation on the other side of the fence can be compared to the potential climax community of the site.  

Case Example:

I was recently watching fence-lines along NM highway 285 from Vaughn to Clines Corners, and noticed that typical overgrazed areas are Grama Grass (Bouteloua gracilis) monocultures or low-stature annuals with large amounts of bare dirt.  The ungrazed roadsides still have bare ground, but the vegetation has a starkly different structure and composition:  multiple grass species occur with different growth forms.  But even more noticeable than the grass growth is the shrub encroachment in an area that is pure grassland.  Without fire or grazing, woody growth, especially saltbush (Atriplex canescens) and  Chimisa (Ericameria nauseosa) increases markedly.

While some trees and shrubs (e.g. E. nauseosa) are resistant to grazing when mature, their seedlings are highly palatable.  Cows can completely eliminate woody overstories from riparian areas in a single generation simply be eliminating recruitment (through both grazing and trampling) of Cottonwood and Willow seedlings.  Grazing pressure on seedlings is important, but easily overlooked: as long as there are trees, we describe an ecosystem as a forest. And it may seem strange to say that cows are eating a forest. But without seedling regeneration, no ecosystem is sustainable.

That grazing impacts woody growth as much or more than herbaceous growth is well-known along rivers and wetlands, but I think has been less remarked on in uplands.  From this brief study of fence-line contrasts, it appears that even more of our grasslands would support shrublands were it not for either grazing or fire limiting woody plant establishment.

Two Soils from the Manzano Mountains

Overview SOIL 1

Apparently frost -heaving has raised very weak physical (WP) crust-mounds.

Closeup of a crust mound:  The surface has been softened and the top centimeter has filled in with fine sediments.  This top layer actually has more structure than the frost-heaved material below it, which readily crumbles into its constituent soil particles.  Note the plant root, at top center of the photo, growing in the fine sediment layer.

Where litter is present, but too discontinuous to form duff, the action of frost heaving rapidly incorporates pine and juniper litter into the mineral horizon.

Overview SOIL 2

Some areas have much more biological crust than others.  In these photos, the blue grama grass Bouteloua gracilis (BOGR) is more abundant with denser cryptobiotic crust.  The darkened biological soil crust (BSC) consists of free-living blue-green algae such as Nostoc. 

Compact SP (strong physical) crust with roots and moisture evident underneath.  These cracked peds come up in 5-8 inch radius plates.  Note how different this crust is from the previous “frost-heaved” crust.  This crust has significant structure to it and doesn’t immediately crumble into constituent particles.  

What Controls Decomposition Rate in Conifer Forests?

Source: Litter decomposition, climate, and litter quality. Link.

Nutrients:  Mn and N

Manganese and Nitrogen control forest decomposition, but in an unexpected way. Mn is an essential component of ligninolytic enzymes important for degrading litter in the later stages of decomposition.  But high available N can limit decomposition. The most efficient degraders of lignin and humic acids are wood-rotting or litter-decomposing white-rot fungi (Hintikka 1970; Hatakka 2001).  For several of the lignin-degrading white-rot fungi, high concentrations of low-molecular weight N compounds suppress the synthesis of the lignin-degrading enzymes (Keyser et al. 1978; Eriksson et al. 1990; Carreiro et al. 2000). 

Further, N has repeatedly been reported to react with remains of degrading lignin to form recalcitrant condensation products. Such products form chemically (Vahtras 1982; Stevenson 1982) rather than biologically.  Spaccini (1999) suggested that such bonds create a hydrophobic surface thereby resisting decomposition. The higher the concentrations of lignin and N in a litter material the more likely it seems that such covalent bonds will be formed. Using 106 sets of foliar litter comprising 21 tree species (both coniferous and deciduous) representing a wide range in chemical composition, Berg (2000) found a highly significant negative relationship between limit values and initial N concentrations in litter.

Many examples exist in which addition of N to a N-deficient system slows down decomposition, especially where organic matter with high lignin content is present (Verhoef and Brussaard, 1990; Carreiro et al., 2000). Nitrogen and other fertilizers may negatively influence specific groups of organisms, particularly microbes.  Any shift in microbial composition can have a negative effect on other soil fauna.  As a result, decomposition and mineralization may decrease. Additionally, plants can compete successfully with decomposers for nutrients.  (Neher 2003.)

What about pH?

In a review of 58 studies, Wardle (1998) found that temporal variability in soil carbon (C) was related most closely to soil N content in forests and soil pH in arable and grassland ecosystems. (Neher 2003.)

But a study by Parn et al adding ash to a pine forest to increase soil pH did not observe increased decomposition.  A large meta-review noted that 22-85% of treatment trials have failed to affect decomposition: “This analysis shows that Ca additions are not universally beneficial and provides insight into when Ca additions to forest soils are likely to be most effective." (Evaluating the effects of liming and wood-ash treatment on forest ecosystems through systematic meta-analysis. Carolyn Reid, Shaun A. Watmough)

Decomposition Rate and Ecosystem Integrity

Neher 2003 "Effects of disturbance and ecosystem on decomposition." is a great review of this topic.  (PDF)  They conclude that "decomposition of organic matter is a useful indicator of soil condition because it is measured easily and serves as integrator of the collective activities of organisms within the soil food web."  For example, slowing rates of decomposition serve as an early warning sign of pathology in forest ecosystems (Bormann and Likens 1979),  A difference in decomposition rate between similar sites implies either a change in the decomposer community or quality of the biotic and abiotic resources at a site. 

This WSU website has a great review of pine forest decomposition.

Biological Soil Crust Restoration?

The biotic soil crust in Red Rock Canyon, Lake Mead National Recreation Area, NV is showing clumps of the dominant moss species, Syntrichia caninervis. Each black dot represents a separate plant. This extreme arid-dwelling moss inhabits the loose sandy soils of the Mojave Desert. [Credit: Alexis Wartelle]

1.  What Biological Soil Crusts (BSC) occur in the desert? Gallery of BSC: from Canyonlands Research Station

Major types (easily observable):
(NB: A misting of water can make crustal organisms more visible...)

Three soil lichens dominate crusts of both the Sonoran and Grea Basin deserts:

Collema: a genus of gelatinous lichen (blackish, jelly-like when moist). First to colonize.

Placidium: a genus of squamulose lichen (discrete rounded flakes, convex or concave). Usually a secondary successional species.

Psora: a genus of squamulose lichen (discrete rounded flakes, convex or concave), a late-successional stage lichen.

Also:
Short moss:  Mosses <10mm and="" b="" bryum="" nbsp="" spp.="">Certodon purpureus 
Heterocystic cyanobacteria: (Notoc, Schizothrix)
Large thalloid liverworts:

Source:  Biological Soil Crusts: Ecology and Management.   Technical Reference 1730-2 2001.

2.  Where do BSC occur?
Soils having high electrical conductivity, high phosphorous, and high salt contents facilitate the
formation of cryptogam crusts. Shrink-swell clays (smectites, montmorillonites dervied from volcanic ash) are the worst.

Sonoran and Chihuahan deserts have more heterocystic cyanobacteria lower lichen, but lichen like Collema, Placidium, and Peltula do occur.  Ecoregions that receive summer monsoons (e.g., the Sonoran Desert) tend to have a greater diversity of heterocystic cyanobacteria (such as Lyngbya, Calothrix, Schizothrix, and Nostoc) and lower lichen abundance. Lichens in these areas generally include the gelatinous genus Collema and squamulose genera Placidium and Peltula.  Large thalloid liverworts are more common in warm deserts than cool deserts.

Sonoran:  heterocystic cyanobacteria (Notoc, Schizothrix), gelatinous (nitrogen-fixing) lichens (e.g. Collema), squamulose lichens, short mosses
Chihuahan:  heterocystic cyanobacteria (Notoc, Schizothrix), short moss


3. Resources for mapping BSC distribution?

Map shrink/swell clays!
Some mosses are on Seinet
Lichen image gallery (from Europe) organized by structure.
Lichens on LichenPortal
Lichens on iNaturalist
USFS Database

New Theories in Evolution and Ecology

Sometimes it can be hard to see progress in biology the way we hear about physics discovering new particles or proposing Grand Unified Theories that explain the entire universe.  It is tempting to believe biology is just too diverse, variable, and multitudinous to be tractable, and that we should content ourselves with Nature-special documentary anecdotes.

But recent research has uncovered at least three major advances toward predicting evolution, social altruism, and a universal explanation of biodiversity. We may soon be able to predict short-term (9-12 month) evolution of the flu virus, rigorously describe conditions necessary for social altruism, and extrapolate biodiversity estimates using insights from thermodynamics.

The complexity, idiosyncracy, and exceptions-to-the-rule in biology are still important, but so too are these simplifying general explanations.  The stories of new "universal laws" linked below are perhaps best thought of as null-theories; jumping-off places rather than destinations in themselves:


1) Predicting Evolution ... Testable Fitness Values (link to article by Carl Zimmer)

Simple selective pressures yield relatively simple predictions: fitness increases linearly at first, but in the long run, weird mutations may diverge populations along novel and unpredictable trajectories.  The tractable problem, then, is short-term evolution, which can still be incredibly important when it is applied to, say, the next 12 months of evolution in the flu virus.  The breakthrough came with the ability to quantify fitness to predict evolvability.

One of the biggest problems of evolutionary theory has been a lack of predictive power, because fitness could only be defined tautologically, post hoc based on survival and reproduction.  If biologists are able to assign fitness ranking with any skill (link) then we may finally be able to understand evolutionary ecology -- the rise and fall of species in their environment.  Will most threatened and endangered species prove to be genetic weaklings, as suggested by this correlational study?

2) Predicting Social Altruism ... What Makes A Good Theory? 

This is an insightful philosophy paper that deconstructs a long-standing debate about whether altruism is predicted by fundamental evolutionary pressures.  The important step forward here is a robust definition of key terms and a searching analysis of what we should expect from abstract mathematical theories.

3)  Predicting Biodiversity .... Metabolic Scaling Laws to the Rescue! 

The tractable problem is to estimate the number of species in a given area when ecologists can only count species in relatively small plots.  The breakthrough came by realizing that only two additional variables (population density and total number of species) are necessary to "collapse" idiosyncratic species-area curves into a single universal curve.

The discoverer, Dr. John Harte, explains:

"If you look at all the known species-area (S-A) curves in the world, of everyplace where somebody’s gathered species-area data, and you plot them all on one big piece of graph paper- log species vs. log area, you will find that the data points fill the graph almost completely. You get every possible behavior when you just do a plot of log S vs log A. There’s no regularity. I didn’t really think that had to be the case. What I learned from developing the theory of macroecology based on the maximum-information entropy principle, is that the theory makes a very startling testable prediction about the shape of the species-area relationship. It says that if you take any species-area curve and you plot the local slope of the log-log plot, what we call ‘z’, at any scale against a certain scaling variable that the theory identifies, namely, the number of individuals at that scale divided by the number of species at that scale, all species-area curves should collapse onto a single universal curve. And it turns out that they do"

(Quoted here.)

Suburban Development Transect: Biodiverse Desert to Trash-filled Parking Lot

2000

2003

2008

2011

A transect walking a few miles from the indisturbed desert through new housing developments into the city looks like time played in fast-motion.  The ecologist's glasses allow us to see the moving picture of life rather than limiting our vision to the usual single frame.  By substituting space-for-time, we can put on time-travel goggles.  What do we see?

Normally we visit a site for a day, maybe once a year for intensive longitudinal studies, maybe never again.  With this transect we could see the changes in species composition from unique, biodiverse desert with its gnarled shrubs to fresh asphalt streets, planted landscaping and lawns, and a monoculture of weeds in the bladed 'empty patches' between houses and in right-of-ways.  The stream channels were all filled in and replaced with impoundments or concrete-lined ditches.

Eventually we ended up in the back lot behind a storage unit complex.  The slight depression there caught water and supported some of the tallest native flowering trees we'd seen.  The lot was also used, apparently, as a dumping ground and was filled with all kinds of trash.

Later that night, back in my home neighborhood, I saw dual-images of what the land looked like before and after development.  I saw the rocky ground thick with idiosyncratic cacti and weird four O'clock flowers.  And I saw wide asphalt streets, joggers, tall pine trees, oleander, and grass lawns.  It is so difficult to see the past, I felt that my dual-vision was a kind of X-ray superpower, a new found ability to see through reality to what might have been.  Reality has a way of erasing the possibility that things could have turned out differently.

A nice walk in the wilderness can sometimes substitute space for space, so that you can see your neighborhood space as the absence of native wildlife instead of the presence of cars, roads, and lawns.  I suppose some people see nature as empty, and even I see it this way sometimes too: some areas are devoid of active communal life.  For example, on this particular transect we saw no rabbits, no ground squirrels, and no other mammals in the wild.  I don't think we saw a lizard until we got to the rock walls of suburbia.  But I was amazed at the botanical emptiness of our developed landscapes: out of the more than 70 native species of wildflowers and Chihuahan desert shrubs, I saw less than 5 after we crossed the first freshly paved asphalt road.

Of course, there are a diverse mix of landscaping plants, many of them native somewhere, if not in the Chihuahan desert.  Interestingly, the mexican palo verde seems to have escaped cultivation and is now growing up into the wild watercourses that snake off the mountains.  Few other weeds seem able to invade intact ecosystems, although Russian thistle is omnipresent wherever the ground has been cleared.

I think, though, that if the transect had continued further into the past/future, through abandoned neighborhoods or restored areas, the native wildflowers and shrubs would reappear.  Especially with the rains this monsoon, they seem quite happy where they are, and old pipelines have a nice covering of desert marigold, creosote, and javalena bush.  I don't really feel that the desert is destroyed by development...maybe in the long-term view it just goes away for awhile, or changes shape for a spell.  Until the wave of bulldozers breaks and subsides, the desert remains as potential...

An Ecologist Ponders the Microbiome

Fluctuating nutrient concentrations and the timing of peristalsis may affect microbiome growth and composition, which is hypothesized to affect health. Certainly digestive upset is no fun for anyone, and it makes sense to look at inputs (diet) as the primary drivers.

Ecosystem arguments are used to claim that some forms of digestive upset are due to over- or under-growth of bacteria in the intestines.  For example, Small Intestine Bacterial Overgrowth (SIBO) is treated with what is called the GAPS diet, an effort to restrict all foods that bacteria can digest.

In response, Jeff Leach, of the American Gut Project, made this comparison between diets disturbing the microbiome and ecological disturbances:

"If you think about it from an ecosystem perspective or from an ecosystem restoration perspective, if you take any ecosystem like the gut, the microbiome, and if you starve it... If you starve your backyard and all the diversity of plants, if you just starve it of nutrients, all ships go down with lowering water. And that perturbation, if you will, it wouldn’t be on the same level as an antibiotic, but it is a perturbation; it is an insult. And when you insult an ecosystem, insults like fire, drought, nutrient overload or nutrient deprivation, any of these perturbations typically result in a flourishing of weedy species, in this case, opportunistic pathogens. I know the GAPS diet...from an ecosystem restoration standpoint, it makes absolutely no sense whatsoever to starve your gut microbiome at any level. "

This idea that "a healthy garden needs a healthy soil" is an ecological idea.  Jeff Leach goes on to claim that specific nutrients, like "resistant starch, non-starch polysaccharides like inulin and fructooligosaccharides and galactooligosaccharides, can provide food for the beneficial bacteria in your gut and can increase their levels by orders of magnitude."

Turns out it may be a false analogy, or if the analogy is valid, the hoped-for predictive power of diet on microbiome function may not hold up. While broad temperature-precipitation drivers do determine biome (e.g. tundra versus desert) it is almost impossible to predict the exact species in an ecosystem based on the nutrient inputs to that ecosystem.  And if microbiome bacteria exert their effects in a species-dependent fashion, it may not be possible to predict that eating x will cause bacteria xyz to grow.

Ecologists look (with envy, and skepticism) at nutrition research and commentary because we know how complicated ecosystems can mess with simplistic notions of cause-and-effect.