New publication - linking neoecology and paleoecology

One of the most fun groups I’ve worked with over the past several years is the NSF RCN Novus network (https://novusrcn.wordpress.com/), a group that has tried to get together “neo” disturbance ecologists - those of us working in the short term, doing fieldwork in disturbed areas, all that - with paleo ecologists. It’s been fun trying to reconcile perspectives and come up with ways to ask interesting questions across timescales.

A new perspectives paper was just accepted in Landscape Ecology where we look at mixing the mechanistic understandings of neo ecology with the deeper time perspective of paleo, and suggest ways to strategically link the two. I think it’s interesting because it’s not talking about individuals - it’s suggesting ways to collaborate strategically and create study designs collaboratively. Not a “tack the paleo on” for a new perspective, but rather to deeply integrate it into the conceptual/proposal stage.

Buma B, Harvey B, Gavin D, Kelly R, Loboda T, McNeil B, Marlon J, Meddens AJH, Morris JL, Raffa K, Shuman B, Smithwick E, McLauchlan K.  The value of linking short and long-term perspectives to understand spatially-explicit ecosystem resilience. Landscape Ecology. In press.

The edge of the world in maps - eye candy

A couple great sketched maps of Isla Hornos, from the old to the new to the newest. Getting closer!

One of the first maps to show Tierra del Fuego as its region, separate from the mainland. This was after the Horn (really, the Hoorn due to the Dutchmen that named it) was doubled for the first time, but prior to several other exploratory firsts including the Falklands being completely described.

 A gorgeous sketch map of Isla Hornos and Cabo de Hornos, edging into the Drake Passage and the goal of the expedition. For more amazing versions, see http://onezillustration.com/projects/

A gorgeous sketch map of Isla Hornos and Cabo de Hornos, edging into the Drake Passage and the goal of the expedition. For more amazing versions, see http://onezillustration.com/projects/

And the most modern view, courtesy of NASA.

New publication - High spatial resolution assessment of carbon reserves

Gavin McNicol, a postdoc in the lab (now at Stanford), has just published his work on coastal forest carbon. Coastal rainforests are the most biomass-carbon dense forest biome in the world, and Gavin focused on building a high spatial resolution/broad extent map of the soil/non-biomass portion of that - which is actually abut 60% of the total. He did a great job, working at 90m resolution across 10 degrees of latitude, a truly difficult task.

In total, we’re looking at approximately 4.5 Pg C in the top 1m, mostly driven by precipitation and topography.

One of the most interesting aspects of the project was Gavin’s comparison to global maps, which are used in global C budgets and models. Our work here is highly detailed, and works with an extensive soil observation network that was put together specifically for this task. So it’s useful to compare and validate global maps, since the scales are at least comparable (e.g., we’re not comparing one observation to a global map, but a huge region/part of the globe).

The global maps are generally pretty poor - 4 fold lower than SoilGrids250m, the finest resolution global map available and significantly more accurate against observations. That was true for other global maps as well.

This type of modeling, at this scale, is quite useful for evaluating global products that are so important for our global change research - they are produced at the right scale for comparison and thus far better for validation than just a series of points that may skew accuracy spatially. I think it’s fairly clear we need more of these types of studies and evaluations.

McNicol G, Bulmer C, D'Amore DV, Sanborn P, Saunders S, Giesbrecht I, Gonzalez-Arriola S, Bidlack AL, Butman D, Buma B. Large, climate-sensitive soil carbon stocks mapped with pedology-informed machine learning in the North Pacific coastal temperate rainforest. Environmental Research Letters. In press.

 One of the truly big tasks was unifying the regional dataset, and perhaps the most work. Above is the extent of the NPCTR displaying the distribution of soil profile descriptions (light green circles) and the study extent (dark green pixels) used in the SOC stock assessment. Inset maps show global (small) and continental (large) extent of the full NPCTR along with the boundaries of climatic sub-regions.

One of the truly big tasks was unifying the regional dataset, and perhaps the most work. Above is the extent of the NPCTR displaying the distribution of soil profile descriptions (light green circles) and the study extent (dark green pixels) used in the SOC stock assessment. Inset maps show global (small) and continental (large) extent of the full NPCTR along with the boundaries of climatic sub-regions.

 Soil organic carbon stock predictions to 1 m (Mg C ha-1) at 90.5 m resolution for small NPCTR watersheds across BC and SE Alaska.

Soil organic carbon stock predictions to 1 m (Mg C ha-1) at 90.5 m resolution for small NPCTR watersheds across BC and SE Alaska.

Sobering assessment of global wilderness areas

As an addendum to the previous post, an assessment of global wilderness came out today as a comment in Nature: https://www.nature.com/articles/d41586-018-07183-6 . Authored by Watson et al., the assessment concludes that (at a 1km resolution w/ a minimum patch size of 10,000 km2) 77% of the earths surface is impacted by humans. The authors specifically call out carbon valuation as a way to potentially justify saving the remaining few areas to skeptics.

The coast of Alaska is one example of some remaining wilderness, or recovering wilderness (in the logged regions). It’s immense carbon stocks are but one aspect of it’s value - perhaps not even the most important part, the wildness which is less substantial but more significant.




New carbon map for the largest C storehouse in the US (and bonus: the role of disturbances)

With the help of USFS FIA technicians, the carbon map of southeast Alaska is completed. It’s the first spatially explicit, high resolution (30m) map of C stocks in the region (an area the size of Florida!) that contains carbon equivalent to 5-8% of the lower 48 forests combined. This mapping also included the major disturbance regimes of the region - wind and landslides - via a new method of mapping exposure. Thus this is far more accurate of “fundamental” or “baseline” C stocks than a map which either ignores disturbances or only uses the most recent events in its calculations - it’s more a map of the inherent C in this ecosystem; recent disturbance events would be layered on top.

Turns out that higher disturbance exposure in these areas is correlated with higher biomass C stocks - it’s so infrequently disturbed that it appears disturbances are necessary to maintain biomass productivity. Without them, paludification and muskeg formation take over - lots of C in those too, it’s just belowground in thick organic soils.

The manuscript is currently in review.

 Modeled biomass C (left), and modeled C when various disturbance processes are removed. Generally we see a reduction in C at broad scales without disturbances (especially landslides) but the effect is variable at fine scales.

Modeled biomass C (left), and modeled C when various disturbance processes are removed. Generally we see a reduction in C at broad scales without disturbances (especially landslides) but the effect is variable at fine scales.

New publication - How global temperate forests change

A new publication, led by Andreas Sommerfeld, is coming out in Nature Communications. In this paper, we looked at 50 forested areas worldwide via high resolution satellite imagery to see what their rates of disturbance were, what the main causes were, and if how those disturbance processes changed as a function of climate. It’s truly a unique look at what drives forest change (fires, wind, landslides, etc), where, and when - and how it might respond to climate change.

Sommerfeld A, Senf C, Buma B, D’Amato AW, Despres T, Diaz-Hormazabal, Fraver S, Frelich LE, Gutierrez AG, Hart SJ, Harvey BJ, He HS, Hlasny T, Holz A, Kitzberger T, Kulakowski D, Lindenmeyer D, Mori AS, Muller J, Paritsis J, Perry GLW, Stephens S, Svoboda M, Tuner MG, Veblen TT, Seidl R.   Patterns and drivers of recent disturbances across the temperate forest biome.  Nature Communications.  In press.

50 total landscapes, from southeast Alaska to New Zealand.

Settling into Colorado, with work spanning the continent

I apologize for the lack of updates, it was a long field season this summer (very successful!) and a busy few months setting up the new lab.  New equipment, like a Costech 8020 Elemental Analyzer, are on the way, and we'll be set for dendro, cellular structure (wood ID), charcoal, and carbon, and high performance geospatial analysis within the month!  

The lab is designed around the idea of scaling from field to landscapes and beyond, a key need in this era of rapid, broad scale changes in climate and disturbance regime.

I am recruiting multiple PhD students. I am especially interested in folks curious about plant community change, fires, and snow loss induced mortality.  So if you are interested in how ecosystems respond to climate change and disasters, and both (!), let me know.

New publication: The phenomena of transitional mortality

Using the lovely study system of yellow-cedar, a new paper explores climate-induced mortality of a different sort than the usual threshold type mortality.  Once I started looking at the whole range, it became apparent that it wasn't so much the climate was too warm for yellow-cedar, but rather the transition from cold-to-warm was detrimental.  In fact, very healthy populations are in quite warm environments.  This led to the conclusion, supported by weather station data spanning about 10 degrees of latitude, that mortality is indeed associated with the transition rather than a threshold per se.  

Capture.JPG

 

The fascinating result is that in this case, slower warming (longer time in the transition) may lead to increased mortality.  It can be captured with a simple binomial model, where the odds for a mortality event are commensurate with the time of exposure climatically and the probability of a thaw-freeze event during that time.  This structure matches the observed data pretty well, though limited data in southeast Alaska (primarily due to a lack of weather stations, and non-random location of those stations) means we're still generally in the hypothesis stage and can't make really concrete conclusions yet - need to move into better instrumented areas and retest (it's science - always retest!).  But it's compelling, and this could be a useful concept in other places.

 Predicted mortality from the simple binomial model which combines years of exposure and the probability of a thaw-freeze event over that time.

Predicted mortality from the simple binomial model which combines years of exposure and the probability of a thaw-freeze event over that time.

The manuscript will be coming out in Ecosphere:  

Buma B.  Transitional climate mortality:  Slower warming may result in increased climate-induced mortality in some systems.  Ecosphere.  In press.