Ad hoc instrumentation methods in ecological studies produce highly biased temperature measurements

In any study which tries to scale grounded field data to a regional perspective, using (as-much-as-possible) unbiased methods is necessary so that data points are comparable across regions.  A good recent paper experimentally looked at the best air temperature sensor design:

Check out the recent paper by Terando et al. It’s open access, available here: http://onlinelibrary.wiley.com/doi/10.1002/ece3.3499/epdf

They experimentally compared 11 different sensor brand and shield combinations to weather station data, and found that quite a few methods had a positive bias. It’s not something we haven’t known is a danger (positive bias due to inadequate/improperly designed shielding), but this is a nice way to standardize methods with some experimental backing behind it.

New publication - How big does your study landscape need to be?

Choosing a landscape extent for study, monitoring, or conservation is difficult once you start considering disturbance processes - it's always possible that a fire, or windstorm, or whatever could come through and drastically change what you're looking at.  This could be fine, but generally when we select landscapes for those purposes we want something representative, something that incorporates disturbances as part of the community and ecosystem ecology of the region (after all, disturbance regimes are a part of the system too!).

This is critical in quantitative ecology at any scale, because few things disrupt a population, community, or ecosystem more than a major fire or a hurricane.  And if we want to truly understand something broader than a single location, we need to know how representative our study system actually is relative to the broader context of the given ecoregion (or system, or whatever).

But how big of a landscape do you need?  The old "rule of thumb" from the 1980's was somewhere between 5-10x the size of the "largest disturbance," but that's really fuzzy.  What you really need is a quantitative analysis of variability in disturbances - how big a landscape such that it doesn't matter where the landscape is, the "disturbance effect" is similar?  This is, in effect, asking how big a landscape extent is required to incorporate that disturbance-driven variability without causing major changes in landscape properties - basically a measure of variance between random landscapes.

So, together with Kurt Riitters at the US Forest Service and Jenn Constanza at NC State, Brian Buma quantified the variability between landscapes at a variety of scales in terms of two disturbance processes - proportion disturbed and contagion (a representation of the shape of disturbances).  This was done for all of North America at a 30m scale, using data from 2000-2014.  Because disturbance regimes vary by region, the data was stratified by ecoregion.

As a first step, we quantified the actual percent disturbed for each ecoregion.  While we used wall-to-wall satellite data, it may also be desirable to set up a series of landscapes that approximate the ecoregion.  In that case, the number of landscapes matters, of course - the more landscapes the better you will be in terms of a representative set (in terms of disturbance area, in this case).  A shows the ecoregions in the boreal denoted by the oblong, northerly circle (large fires); B shows the ecoregions on the North Pacific coast (very low disturbance frequency, small events).  With larger landscapes, one gets a good idea of actual proportion disturbed more rapidly of course.  The actual map (bottom) is the true average, and a nice reference tool when writing proposals - what is the "normal" fraction of disturbed area in my study system?

As a first step, we quantified the actual percent disturbed for each ecoregion.  While we used wall-to-wall satellite data, it may also be desirable to set up a series of landscapes that approximate the ecoregion.  In that case, the number of landscapes matters, of course - the more landscapes the better you will be in terms of a representative set (in terms of disturbance area, in this case).  A shows the ecoregions in the boreal denoted by the oblong, northerly circle (large fires); B shows the ecoregions on the North Pacific coast (very low disturbance frequency, small events).  With larger landscapes, one gets a good idea of actual proportion disturbed more rapidly of course.  The actual map (bottom) is the true average, and a nice reference tool when writing proposals - what is the "normal" fraction of disturbed area in my study system?

The proportion of the landscape disturbed varies quite a bit at small landscape extents - unsurprisingly.  At a small extent, a random landscape might be within a burned area or in a location completely undisturbed.  At broad extents, however, most landscapes had fairly low variability.  In other words, it didn't matter where the disturbance occurred, it was incorporated into the landscape.  

Of course it depends where you are - some boreal ecoregions, with their big fires, still had high variance from landscape to landscape even at our largest extent.  And contagion takes longer to settle down.  But for many ecoregions, there are practical extents such that, at least under current disturbance regimes, you can be fairly confident that any future disturbance will be incorporated just fine, rather than completely shifting your landscape to something non-representative.

We also include a parallel analysis where we focus only on disturbed pixels themselves, useful to those researchers who are going to be looking at disturbance processes - how big an area around the disturbance do you need to get a real image of the broader ecoregion?

These results are critical in scaling and communicating the significance of ecological research that attempts to put these dynamic change processes into their broader ecoregion context. 

The results are in press:  Buma B, Costanza JK, Riitters K.  Determining the size of a complete disturbance landscape:  Multi-scale, continental analysis of forest change.  Environmental Modeling and Assessment.  In press.

If you're concerned about your landscape being disturbed, then setting your landscape size larger than these values (in kilometers squared) will reduce the likelihood of a disruption.  The values represent the minimum landscape size to reduce the standard deviation between landscapes below 10% - in other words, it's fairly unlikely (though not impossible!) that a disturbance will make any given study landscape of that size, or larger, dramatically different from the rest of the ecoregion.   All summary statistics, for all ecoregions, included as Supplementary Data and available here and in the paper.

If you're concerned about your landscape being disturbed, then setting your landscape size larger than these values (in kilometers squared) will reduce the likelihood of a disruption.  The values represent the minimum landscape size to reduce the standard deviation between landscapes below 10% - in other words, it's fairly unlikely (though not impossible!) that a disturbance will make any given study landscape of that size, or larger, dramatically different from the rest of the ecoregion.   All summary statistics, for all ecoregions, included as Supplementary Data and available here and in the paper.

John Krapek's second thesis paper featured on cover of Diversity and Distributions

Congrats to John, whose second paper from his MS thesis was selected as the cover shot for Diversity and Distributions!  

Krapek J, Hennon PE, D’Amore DV, Buma B.  Despite available habitat, migration of climate-threatened tree appears punctuated with past pulse tied to Little Ice Age climate period.  Diversity and Distributions. 23(12): 1381-1392

Available here and on the Publications page.

John Krapek and Alex Bothello mapping individual stems along the northern migration front of yellow-cedar, a species currently dying rapidly due to climate induced changes in snow cover.

John Krapek and Alex Bothello mapping individual stems along the northern migration front of yellow-cedar, a species currently dying rapidly due to climate induced changes in snow cover.

  

 

Glacier Bay study on NPR's Here and Now today

An update on our Glacier Bay work, covering not only the 1916 rediscovery but also audio from the 2017 expedition, will be on Here and Now today.  The coverage includes a bit of what we did. Thanks to Elizabeth Jenkins at KTOO for putting the initial report together.

Capture.JPG

Also...  

More highlights - Not only have we mapped the vegetation around these plots for a complete, statistical analysis of spatial characteristics in the aboveground community (it's odd that there isn't much succession actually happening - the spatial stats will help us understand why), we are also sequencing bacterial and fungal diversity at specific locations within the plot network, so we can link community evolution belowground to community evolution aboveground.  This hasn't been attempted on anything approaching the timescales we have available here, so it should be really interesting!

http://www.wbur.org/hereandnow/2017/10/30/alaska-glacier-ecology-records

 

Expert meeting to discuss yellow-cedar status and Endangered Species review

Together with the Alaska Coastal Rainforest and with funding from US Fish & Wildlife, several experts and interested policy makers from the US and Canada are meeting in Juneau, Alaska next week to discuss yellow-cedar decline, range considerations, protected status, genetic health, and other issues pertaining to the health of the species.  The two day event will be held at the University of Alaska Southeast.  I encourage all to come, or tune in, to the talks - this is a complicated phenomena, with significant implications for any decision made in terms of protected status.

The schedule is below.  It will be in the Rec Center classrooms on the UAS campus.  Contact Brian Buma for call in information.

Schedule:

Tuesday, Oct 24

9:00                  Coffee

9:30                  Welcome and opening notes – Allison Bidlack, Alaska Coastal Rainforest Center and Steve Brockmann, U.S. Fish and Wildlife Service

9:45 - 10:15      Introductions

 Session 1 – Yellow-Cedar Biology, Adaptations, and Ecological Requirements        

10:15 - 11:00    Deep biology of yellow-cedar – Paul Hennon

11:00 – 11:30   Yellow-cedar: A genetic perspective – Rich Cronn

11:30 - 12:00    A chemical-genomics approach to stress response traits in western red-cedar and yellow-cedar - Jim Mattsson

12:00 – 12:30    Discussion

Session 2 – Current Status, Distribution, and Populations

1:30 - 2:00        Current range and decline model of yellow-cedar:  Development and current status - Brian Buma

2:00 – 2:30       Is climate driving yellow-cedar decline on Haida Gwaii? – Vanessa Comeau

2:30 - 3:00        Young-growth yellow-cedar: Improving our database and monitoring decline – Liz Graham

3:00 – 3:30       Measuring and monitoring extent and severity of yellow-cedar decline in Alaska - Tom Heutte

3:30 – 4:00       No evidence of recent (1995-2013) decrease of yellow-cedar in Alaska, response to questions – Tara Barrett

4:00 - 5:00        Discussion

Wednesday, Oct 25

8:30                  Coffee

Session 3 – Economic and Cultural Uses, Silviculture, and Conservation

9:00 - 9:30        Silviculture and conservation of Alaska yellow-cedar on the Tongass - Sheila Spores

9:30 - 10:00      Status, utilization and silviculture of yellow-cedar on private lands in southeast Alaska – Brian Kleinhenz

10:00 - 10:30    Is yellow-cedar being overtutilized in Alaska? - Sue Bishop

10:30 - 11:00    Discussion

Session 4 - Outlook and Future Scenarios

11:00 - 11:30    Long-term vegetation changes in forests impacted by yellow-cedar decline, future vulnerability, and implications of the climate-induced dieback for human uses and values - Lauren Oakes

11:30 - 12:00    Research and monitoring opportunities in managed and unmanaged landscapes that correspond with yellow-cedar’s health status - Paul Hennon

1:00 – 1:30       Microclimate drivers of decline, regeneration, and forest compositional shifts in yellow-cedar forests of southeast Alaska – Sarah Bisbing

1:30 – 2:00       Yellow-cedar regeneration at the edges of its range - John Krapek

2:00 – 2:30       Chasing the grey ghosts: Ecological anomalies of Haida Gwaii cause a conservation planning nightmare – Nick Reynolds

2:30 - 3:00        Nightmare on cedar street? Climate projections for yellow-cedar mortality across the entire range - Brian Buma

3:00 – 5:00       Discussion: Remaining Questions and Research Needs

New publication: Yellow-cedar community ecology and conservation concerns

The ecological story of yellow-cedar is interesting not only as an interesting species that shapes the biogeochemical and community ecology of its surroundings, but also from a conservation point of view, as the advanced cedar stands which represent the northern range edge are the best sign of an ability to migrate with climate change - except they aren't moving.  A new publication explores these community and regeneration aspects in depth:

Krapek J, Buma B.  Persistence following punctuated range extension: limited dispersal of migrating tree despite habitat ahead of its range.  Journal of Ecology.  In press.

Two graduate opportunities- PhD in fire ecology, MS in landslide ecology; both carbon and community ecology focused

Two exciting new opportunities are available in the Buma lab.  Both are funded.  Both focus on carbon dynamics in very significant, C-dense forest ecosystems, and how multiple disturbances can interact to create interesting new vegetation and C changes.

First, the PhD position:

A PhD position is available starting Summer, 2018, with Dr. Brian Buma at the University of Alaska Fairbanks and Southeast.  This exciting opportunity will take the student throughout Alaska, and focus on the interaction between multiple wildfires and subsequent changes to carbon and permafrost cycling.  The PhD position is part of a large, multi-institution effort (UAS, UAF, Florida, Portland State) to link vegetation resilience, permafrost changes, and carbon cycling dynamics into high spatial resolution modeling framework to forecast the effects of climate change on high latitude, boreal systems.

The position will entail:

Extensive fieldwork in Interior Alaska, focusing on plant regeneration after 1-3 fires
Carbon cycle accounting
Assistance with permafrost and soil measurements
Coordination with modeling researchers
Charcoal and black carbon quantification (lab based)
GIS/remote sensing

Applicants should have a Bachelors and/or Masters degree in biology, environmental science, chemistry, or other quantitative field.  Ideally, applicants will also have field experience and be comfortable in remote locations for up to two weeks at a time.  The applicant should also be independent, self-motivated, and excited to take on a challenging project that will help shape our understanding of climate change in boreal systems world-wide.  The paid position will begin with fieldwork in Summer, 2018, before progressing to graduate classes in Fall, 2018.

The position will be partially based in Fairbanks, Alaska (initially) and then Juneau, Alaska. Both towns offer a unique, Alaskan experience.  Fairbanks is known for its research university, boreal forest setting, and cold, clear winters; Juneau for its coastal temperate rainforests, salmon, glaciers, and bears.

Please contact Dr. Brian Buma (bbuma@alaska.edu) for more information.  Include your CV and letter of introduction, and please check out the lab website (www.brianbuma.com) for more information on other projects going on in the lab.

Boreal forest fire

Boreal forest fire

 

Second, the MS position:

A Masters position is available starting Fall 2018, with Dr. Brian Buma at the University of Alaska Fairbanks and Southeast.  This exciting opportunity will take the student throughout Alaska, focusing on one of the most pristine forest ecosystems in the world, the coastal temperate rainforests.  The MS position, funded for two years, will focus on the role that landslides and windstorms have in shaping the distribution of carbon via extensive fieldwork and coordination with modeling scientists at Portland State University.  This research project is significant not only from an ecosystem/carbon perspective, but also because landslides are a significant threat to life and property in many parts of the world, including locally, and skills learned here will transfer not only to research and academic positions but also NGO’s, governmental and natural disaster organizations, and others.

Fieldwork will primarily be located in Sitka, Alaska, through the Sitka Sound Science center.  Sitka, one of the oldest (non-Native) towns in Alaska, is a beautiful town on the Pacific coast, known for its old-growth forests, brown bears, and beautiful views.

The position will entail:
Extensive fieldwork in coastal Alaska, focusing on carbon dynamics and distributions
Soil depth and type measurements
Coordination with modeling researchers
GIS/remote sensing

Applicants should have a Bachelors degree in biology, environmental science, chemistry, or other quantitative field.  Ideally, applicants will also have field experience, OK traveling by boat and float plane, and be comfortable in remote locations for up to two weeks at a time.  The applicant should also be independent, self-motivated, and excited to take on a challenging project that will help shape our understanding of forest disturbance and change processes.  The position will begin in Fall, 2018, through the School of Natural Resources and Extension at UAF.

The academic year will be partially based in Fairbanks, Alaska (first year) and then Juneau, Alaska (second year). Both towns offer a unique, Alaskan experience.  Fairbanks is known for its research university, boreal forest setting, and cold, clear winters; Juneau for its coastal temperate rainforests, ecotourism, salmon, glaciers, and bears.

Please contact Dr. Brian Buma (bbuma@alaska.edu) for more information.  Include your CV and letter of introduction, and please check out the lab website (www.brianbuma.com) for more information on other projects going on in the lab.

New publication: Ongoing species migration due to historical (and current) climate change

Determining the rate of species spread at leading range edges (and contraction at trailing edges) is critically important to projections of species survival under climate change - conservation and management are all contingent on those estimates.  Some species are projected to move rapidly, but we're lacking a lot of contemporary studies of ongoing migration of dominant forest species.  There are lots of paleo records of historical movement, but less so of contemporary migration, because in many cases it's been accomplished.  Few cases of current movement - not from anthropogenic warming, but warming after the last major glaciation (circa 15,000 years ago) - are documented.  Lodgepole pine is one, and it's very interesting - another is Alaska yellow-cedar.  

The Alaska system can tell us quite a bit about how potentially dominant, canopy species move through intact forests - not an easy task.  It's one thing to move into recently deglaciated landscapes, or during periods of disturbance (like lodgepole).  What about intact and healthy, functioning ecosystems?  Are they more or less difficult to migrate through?  It's not an easy task.  Intact ecosystems are tight places, and most resources are spoken for.  It's also challenging to study.

First, John had to determine if yellow-cedar was indeed migrating, as hypothesized.  It appears that Alaska yellow-cedar is moving north, and has been, since the last Ice Age.  A recent paper by John Krapek, who did this work while a Masters student in the lab, now outlines that leading range edge and documents the extent to which the species has yet to move - in essence, the rate at which cedar is lagging behind climate.  Yellow-cedar appears to pulse forward, rather than smoothly tracking climate, with the pulse being dependent on snowy conditions - specifically the Little Ice Age a few centuries ago.  This is not good news, as those conditions are becoming more and more rare.

Through multiple lines of investigation, John was able to trace the establishment of leading populations of yellow-cedar (small groups ahead of the main range of the species) and model the overall available niche, as well as look forward to see if the landscape will remain hospitable.  It's a great read.

Krapek J, Hennon PE, D'Amore DV, Buma B.  Despite available habitat at range edge, yellow-cedar migration is punctuated with a past pulse tied to colder conditions. Diversity and Distributions.  In press.

The northerly edge of Alaska yellow-cedar is comprised of small populations north of the main range boundary.  These stands (from 1-50+ trees) are small, isolated, and represent migration due to climate warming - and can tell us quite a bit about the rate of migration and how species move through intact ecosystems.  This figure shows estimates for when those stands established (minimums).  The leading edge appears to be comprised of populations which got their start near the tail end of the Little Ice Age.  

The northerly edge of Alaska yellow-cedar is comprised of small populations north of the main range boundary.  These stands (from 1-50+ trees) are small, isolated, and represent migration due to climate warming - and can tell us quite a bit about the rate of migration and how species move through intact ecosystems.  This figure shows estimates for when those stands established (minimums).  The leading edge appears to be comprised of populations which got their start near the tail end of the Little Ice Age.  

New NSF grant will explore the dynamics of landslides, wind, and carbon in the dense forests of Alaska

A newly funded collaborative project between the University of Alaska Southeast and Portland State University is going to explore the role of landslides and wind disturbances in landscape carbon distribution.  Landslides move a lot of debris - most people think of them as primarily a movement of earth, but in some areas (forests) they move a ton of carbon, in the soil yes, but also in the trees they bring down.

Starrigaven landslide, photo Sitka Conservation Society

Starrigaven landslide, photo Sitka Conservation Society

The role of those debris in controlling how the landslide moves and travels is relatively unknown, and so Adam Booth, a geologist at PSU, is going to be building a modeling framework to incorporate woody debris into landslide mechanics.  Meanwhile, I will be leading an effort to explore the carbon implications of those movements and incorporate that into the model as well.  When completed, we will then model the entire landscape to understand what role these disturbances play (over long time spans) in the spatial distribution and movement of carbon in these world-class carbon storehouses.

Kramer landslide in Sitka, 2015.  It killed three people.  Photo KCAW.

Kramer landslide in Sitka, 2015.  It killed three people.  Photo KCAW.

There's more implications here than just carbon and forests.  Landslides kill people, and have recently, in southeast Alaska and around the world.  Many cities, in the US and abroad, are exposed to landslides. By being able to better predict their movement, travel distance, and route, as well as how the forest plays a role in stability or destructiveness, we will be better able to help municipalities plan for these natural events (only expected to get worse as climate change increases the frequency of intense rainfall events in many locations).