New paper in PNAS: Negative effects of greater aridity on soil microbial abundance and diversity

As the planet warms, many of its dryer regions (~ 40% of the land surface), would be expected to become more arid. This is because heat drives evapotranspiration, and evapotranspiration strongly influences dry land soil moisture (even more than  the amount of precipitation that falls). Based on what we know of more arid climates, we might expect that increased aridity will result in less plant productivity. But what will happen to soil microbes? Plants and soil microbes are the twin pillars of ecosystem function. If they decline, we might also see a decline in the functions they contribute to such as the creation and maintenance of soil fertility. That would be further bad news.

So, how would somebody study the effect of increasing aridity on soil microbes at the global scale. Experimentally, you'd have to decrease rainfall input into soils or warm soils in several locations, then measure the diversity and abundance of the microbes. The problem is this gets expensive, and its hard to find research funding to spend in different areas of the world. Also, we'd have to pick one or two experimental treatments to focus on (for example, a 50% reduction of precipitation or a 2 degree warming of soils). We don't know for sure how climate change will play out in local areas, so we could be picking the wrong treatments if we went that route.

But, what if you wanted to do this for much less money, and at the same time increase the number of sites you sampled. You could just sample aridity gradients in many places around the world, and find the general relationship between aridity and microbial abundance and diversity. From that you could make predictions about what warming and increasing aridity would do to soil microbes without having to know how much aridity might increase.

This was all cooked up by Fernando Maestre several years ago when I was a post-doc in his lab at Universidad Rey Juan Carlos in Spain. He developed a set of methods that labs around the world could perform with just a little bit of funding, and accepted their soil samples for analysis. Then he assembled a team of collaborators around the world. I happily accepted a trip back to the US with my (now) wife, Becky Mau (ECOSS, NAU) to conduct some sampling stateside, and contribute to the effort. Other researchers have added value to this dataset, for example by getting new soil samples, properly preserving the DNA in the soils until molecular characterization of the soil microbiota could be performed by cooperators at University of Western Sydney, Australia.

We've collectively published a lot of cool studies from this sampling effort, and I'm happy to say the latest is out in PNAS. So, what about the microbes? It looks like both the abundance and diversity of both fungi and bacteria are likely to decline if aridity increases in a given dryland. Of a handful of  possible specific mechanisms, this seems most closely linked to less soil carbon in more arid regions, although the variation in temperature is also influential. Finally, on the bacterial side, there are also shifts in which phyla dominate the community as one goes from less to more arid sites.

Journal website

Press release from NAU news

Future of Northern Arizona's Lanscape Panel Discussion, Dec. 3 6:30 PM, Coconino Center for the Arts

Please come out to the Future of Northern Arizona Landscapes event next week. Three NAU School of Forestry professors will be presenting short talks and taking questions, along with 2 other speakers from NAU and the Grand Canyon Trust. For my part, I will focus on ways to assist migration of plants by co-migrating soil organisms. The event is sponsored by The Flagstaff Climate March and is one of a series of events coinciding with the COP 21 (UN Climate talks) meeting in Paris. Read more about it here http://www.flagclimatemarch.com/events.html.

Publication backlog post….three from earlier this year

The Spanish post-doctoral power trio is at it again. Somebody hire these men! Santi & Manu have published the results of our fun and productive road trip across the Colorado Plateau back in summer of 2012 (?), part of a global drylands dataset dreamed up by Fernando Maestre. Raul has published some more work from his N-deposition study using an array of study sites across Spain.






Soliveres S., Maestre F.T., Ulrich W., Manning P., Boch S., Bowker M.A., Prati D., Delgado-Baquerizo M., Quero J.L., Schoning I., Gallardo A., Weisser W., Muller J., Socher S.A., Garcia-Gomez M., Ochoa V., Schulze E.D., Fischer M., Allan E. 2015. Intransitive competition is widespread in plant communities and maintains their species richness. Ecology Letters 18:790-798.

Ochoa-Hueso R, Delgado-Baquerizo M, Gallardo A., Bowker M.A., Maestre F.T. Climatic conditions, soil fertility and atmospheric nitrogen deposition largely determine the structure and functioning of microbial communities in biocrust-dominated Mediterranean drylands. Plant and Soil doi:10.1007/s11104-015-2695y.

Delgado-Baquerizo M. Maestre F.T., Eldridge D.J., Bowker M.A., Ochoa V., Val J., Singh B.K. 2015. Biocrust-forming mosses mitigate the negative impacts of increasing aridity on ecosystem multifunctionality in drylands. New Phytologist doi:10.1111/nph.13688. 
(See also Research Highlight in Nature Plants Article Number 15177-15181).

CRC Features our Biocrust Restoration work

This fall we set up two experiments at the Canyonlands Research Center. In the first, we transplanted intact biocrusts to three "home" or "away" locations from 1200, 1600 and 2000m to determine if biocrusts are best adapted to their home environment, and thus need to be locally sourced for restoration. In a second experiment, we are testing method to successfully establish greenhouse-cultivated biocrusts to the field to maximize success for future restoration efforts.

You can read the Fall 2015 CRC newsletter, the Sundial, which highlights our work along with others doing important work on biocrust and vascular plant restoration: http://canyonlandsresearchcenter.org/

A rainbow over our newly-established biocrust common garden. Light rains welcome the biocrust transplants to their new home.

In a full-factorial experiment, we are testing methods to ease the transition of greenhouse cultivated biocrusts to the field to maximize establishment. Methods tested here include: hardening of inoculum, jute addition, and water addition for 2 weeks following introduction to the field.

Straw checkerboards show promise in stabilizing soils, and providing good habitat for biocrust establishment. We are testing it's effectiveness with no inoculum, greenhouse cultivated inoculum, or greenhouse cultivated and hardened inoculum.

Rooftop Mosscaping Project Begins on the Pods of the ARD Building at NAU

Today NAU grounds personnel and representatives from the Bowker Lab kicked off the first installation of biocrust mosses on a campus building roof.  The objective of the project is to create a zero maintenance and zero water input green space that can both sequester carbon and beautify the campus.

Much of the roof of the ARD building's Pods was already colonized by pioneer species of mosses including Bryum argenteum and Funari hygrometrica. These moss species, in addition to other species local to the greater Flagstaff area, were transplanted in a dense mosaic within view from the second floor of the building. This is the first of multiple efforts to develop the Pod roof, which will include native vascular plant species as well.

While mosses have been incorporated into green roof architecture globally, this concept has not been developed in the Southwestern US or other arid regions. The effort is the first of its kind, bringing biocrust restoration techniques developed at the Bowker lab to an urban context. We would like to thank NAU grounds for collaborating with University researchers to explore sustainable, climate conscious, landscaping.

Biocrust session in the books. Thanks!

The crusties & entourage taking over Dara Thai. We are stretching all the way to that back wall!

Huge thanks to everyone who made the biocrust session at the 13th Biennial Conference on Science & Management on the Colorado Plateau and Southwest Region a stunning success. Special thanks to the students who were the real organizers: Ana Giraldo (ASU), Carrie Havrilla (CU),  Chris Ives (NAU), Kristina Young (NAU). Thanks also the School of Forestry and Merriam-Powell Center (NAU), and USGS for making it all happen.

This is the third such session in a row, and the fourth if we go back a few years. 

We had friends and collaborators from as far as Missoula and Berkeley and Corvallis, and the usual suspects from Boulder, Moab, and Tempe.... cementing this as one of our favorite events. See you next time.

Biocrust Special Session of the Biennial Conference of Science and Management on the Colorado Plateau & Southwest Region

The Biennial Conference is here at NAU next week, and we really excited about the speakers presenting at the Biocrust Special Session, which is happening on Wednesday, October 7th in Agassiz room.

Here is a link to the conference schedule, which includes the biocrust special session: Biennial Conference schedule

Lab members presenting include:
Anita Antoninka
11:55–12:15 RESTORING THE LIVING SKIN OF THE EARTH: PROGRESS IN BIOCRUST RESTORATION IN THE GREAT BASIN AND CHIHUAHUAN DESERTS. ANTONINKA, A., M.A. Bowker, N. Barger, S. Reed, J. Belnap, K. Doherty

Kristina Young
1:35–1:55 USING BIOLOGICAL SOIL CRUST FOR SOIL STABILIZATION AND RESTORATION. YOUNG, K.E., M.A. Bowker, S.C. Reed, M.C. Duniway, and J. Belnap

Matthew Bowker
1:55–2:15 RAPID CULTIVATION OF N-FIXING LICHENS AND BIOCRUSTS FOR REHABILITATION OF DRYLANDS. BOWKER, M., A.J. Antoninka, S.C. Reed, K.D. Doherty, J. Belnap, N.N. Barge

Chris Ives
2:35–2:55 FIRE MOSS AS A TOOL FOR POST-WILDFIRE ECOSYSTEM RESTORATION. IVES, C.I.

Also be sure to check out Mike Remke's talk on Tuesday in the Genetic and Genomic Approaches for Mitigating Impacts of Climate Change and Exotic Species Invasion on Wildlands – Invited Session.
2:00–2:15 THE ROLE OF MYCORRHIZAE AND SOIL ORGANISM COMMUNITIES IN RESTORING A NATIVE GRASS, BOUTELOUA GRACILIS, IN THE FACE OF A DYNAMIC CLIMATES AND EXOTIC SPECIES INVASION. REMKE, M.J., M. Bowker, and N.C. Johnson

Finally, there is one additional biocrust talk by Carla Roybal outside the special session in the Plant Ecology General Session on Thursday in the Fremont Room, don't miss it!:
9:00–9:15 NUTRIENT ADDITION CHANGE NITROGEN FIXATION RATES OF COLORADO PLATEAU SOIL CRUST. ROYBAL, C.M., and S.C. Reed