Fall 2015 Field trip

The Ephedra regional gradient experiment is up and running for round 2. In summary from our work last year, we have seven sites spanning a regional gradient of continentality, starting in Panoche Hills and ending in Tecopa/Sheephole Valley. The addition of Cuyama was great as it gave us intermediary representative that is west of the Mojave, other than Panoche Hills. At each of these sites there are 30 shrub-open pairs, totalling 420 independent plots.
Planting
At each of those plots I had a split-plot for three separate plant species (Salvia columbariae, Plantago insularis and Phacelia tanacetifolia). Each split plot was about 20 cm long and 10 cm wide. I chose these species because they represent different families and traits, but more importantly because of their regional distribution. Salvia is more eastern Mojave, Phacelia more Central valley and Plantago equally distributed. Each plot was randomized per species and 0.3 grams of each species (~30 seeds) was sowed with a light dusting of sand put on top. In total, approximately 40,000 seeds were planted.
Climate
Our experiment spans a gradient of increasing heat and decreasing precipitation. I like how it is set up because it has two sub-gradients contained within. There is the latitudinal gradient with increasing distance from ocean that generally correlates with precipitation, but also a longitudinal gradient among Tecopa, Hwy40 and Sheephole that correlates with temperature. This should be an interesting test to compare as well to see if which of the two are driving the facilitation effect as well as the overall gradient. To supplement the global datasets determining the gradient, 6 HOBO ProV2 loggers were placed at 3 shrub-open pairs at each site. These loggers will measure hourly for the entire duration of the field season to validate the gradient and compare the microclimate effects between shrub-open.
Nutrients
From our discussions, we are also interested in the nutrient angle. There is enough evidence now, and some great new work coming out of the Armas lab, that shrubs mechanistically alter the nutrient content within understorey canopy favouring plant growth. We are interested in seeing if along this regional gradient, nutrient content changes as well as abiotic stress amelioration. At half of the pair plots at each site I added nutrients to supplement the ground content. I predict, that the nutrient addition will have a more pronounced effect in the most extreme sites, were nutrient availability is low. We discussed conducting nutrient analysis of the soil that I believe are we still intending to do. I also put out different cellulose types (bamboo skewers and filter paper) to measure decomposition rate at these sites.
Genetics
From a discussion with Ben Evans, and Mike Westphal, I think we are committing to genetically analyzing the facilitator, Ephedra californica. There has been work (Valiente-Banuet, Verdu, etc) that tests how shrubs favour genetic diversity by increasing competition between conspecifics. However, there is little work testing how the genetics of the benefactor relates to the ability to facilitate (quite a different question). Unfortunately, there is a little work on Ephedra in general and none I can find into the genome (other than a distance Old World species). I think a more simplistic genetic approach, potentially using barcoding, would be ideal. Of our seven Ephedra populations, we identify the genetic relatedness and how that effectively maps onto the facilitation effect of the shrub. I haven’t taking the samples of Ephedra yet, but it is something I will look into for my next trip to California.
Water
This year is an El Nino year and it is expected California will get a lot of rain. Unfortunately, an El Nino year increases the probability of rain, but there are never any guarantees. This means that our extremely strong El Nino event could still result in a drought year. At the sites I went to, there was no emergence. Some area of the Mojave have seen rainfall/emergence, but I think we have successfully time our planting prior to the “big” rains. Panoche Hills the day I was leaving had a 90% probability of rain, the highest I have seen it for almost 6 months. Conclusion? If California gets its expected heavy precipitation, then our seeds should take and our phytometer in full swing. The other side to this coin is that some areas may see too much rain. For instance, hwy 58 and Death Valley had some extremely heavy rainfalls that lead to some significant damages (http://bit.ly/1Q40MHQ). It is a good thing then we have 7 sites because a dramatic rain event might erase one of them.
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Seed trapping!

Originally when I started in the graduate program my thesis was to be based around seed trapping, however, the only experiment I conducted on it has yet to be analyzed. Now I have the data compiled and looking for certain trends. There is a still much more to go, but here is a quick initial finding. With increasing distance from shrubs, there is significantly less seeds present in the transient seedbank. The most amount of seed was found at drip line of the shrub, with less and at further distances away. Interestingly, the least amount of seeds were recorded well within the shrub canopy. This means that the physical obstruction of the drip line is catching seeds preventing them from blowing in the open or reaching too far into the shrub itself.

seed trapping

Ephedra the hydra?

Week 6 into the experiment and Brome has grown quite significantly. Ephedra is definitely lagging behind, but still many plants are over 8 cm tall, which is considerable. One interesting finding is that every cut Ephedra seedling develops into three new branches. This additional branching may be a restoration technique that could help promote Ephedra growth early on and get it more quickly established in the system. We shall see!

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Indirect interactions through removal experiments

We conducted a field experiment to test the strength of interactions among understory plants to a dominant woody species. The experiment consisted in removing all herbaceous neighbours around two target annual plant species (Fuertisimalva peruviana and Plantago limensis), which grow in the understory of the tree Caesalpinia spinosa. Treatments were four: (1) target species with neighbours (N+) under the canopy of C. spinosa; (2) target species without neighbours (N-) under the canopy of C. spinosa; (3) target species with neighbours (N+) in open nearby microsites; and (4) target species without neighbours (N-) in open nearby microsites. After the removal treatments we meadured plant height, fruit production and final biomass. The main results are as follows:

 

Fig3newsig The Figure above shows that the effects of interactions as mediated by dominant plants are species specific (statistical significance is denoted with *). Mostly P. limensis displayed differences in response to removal treatments, and even those differences varied among the response variables measured.

 

 

Fig4newsig

Relative interaction indices (RIIs) also show that P. limensis responded differently in comparison to F. peuviana. For example, for 2012, the neighbours effect on biomass was stronger in open microsites. These results show that the importance of indirect effects mediated by dominant plants is species-specific, which in turn allows for coexistence in such microsites and maintains plant biodiversity at the landscape level.

 

Filters limiting Ephedra recruitment

Less than a week into the experiment and it doesn’t seem too surprising why Ephedra is struggling to recruit at Panoche Hills. Brome quickly germinated and has grown five times taller than an Ephedra seedling. It will be interesting to see how the different treatments impact this relationship

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Ephedra restoration experiment

We’re off! A little late in the summer but the Ephedra-Brome experiment with varying stressors has been set up. 3 experiments occurring simultaneously testing the effects of watering, simulated herbivory and %PAR on competition between Bromus madritensis & Ephedra californica seedlings. In total, 700 pots, ~10,000 seeds and one fine looking shade shelter. Should make for a good experiment! Thank you to Steven for all your help setting it up.

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Positive interactions @ ESA100

Niche mediation/niche construction/niching: The dominant plant (shrub, cushion, tree, etc) can increases the suitable area for a plant species by reducing abiotic or biotic pressures. As E. McIntire has pointed out though, positive interactions generate more area with the same fundamental niche characteristics, rather than expanding the niche itself. Thus, removal of limiting factors on the beneficiary by the benefactor will not increase the realized niche beyond that of the fundamental niche. If biotic limitations are zero, then the realized niche will simply equal the fundamental niche.

Realized Niche = Fundamental niche – biotic limitations (sensu Hutchinson)

The dominant plant will therefore either 1) increase habitat availability by generating the same microclimatic conditions of the fundamental niche for a species; i.e. increasing the area of the fundamental niche or 2) Reduce biotic limitations, such as herbivory or competition, that prevent a species from occupying areas of their fundamental niche. Both these situations have the same perceived response (a range expansion), however, I believe they have different implications for ecology and conservation.

Semantics of facilitation: The original definition of facilitation stated, roughly, is a positive effect between two individuals that is non-trophic based. I think we have assumed that this means it remains within trophic level, but A. Liczner has pointed out that this may not be the reasoning behind the original definition. Instead, it may be to imply a positive effect that is not trophic. For example, a shrub would not be facilitating a deer by being eaten, but would facilitate a deer by providing shelter. I also think “facilitation” can be a challenging term because what would the opposite be for facilitation? Competition? But not all negative effects are competitive. For instance, a shrub deterring herbivory is often classed as facilitation, but if a shrub attracts herbivores what is it? I think the general classification of positive or negative interactions act as good umbrella terms, but not sure what to do when going more specific.

Beyond the stress gradient hypothesis: There was other semantic discussion on the term “stress” and how it may be time to move away from stress as if it were a quantifiable measure and instead discuss the gradient that is being measured (temperature, soil moisture, etc). Smit actually took this one step further and stated how we should also measure the response of stress on the plant. Simply correlating water availability with plant biomass or abundance is not sufficient to determine if a plant community is stressed, because these communities may have adapted different life-history traits (sensu Grime). Additionally, there should be a bigger push to study other approaches that are not singular mechanisms (similar to what I proposed in my review). Instead, as we concluded, there should be further work in other areas of research such as: animals, indirect interactions, “unpopular” mechanisms or mechanisms in combination.

research

#ESA100 in Baltimore

As a first time ESA goer the whole experience was pretty wild. There was nearly 4000 people in attendance of the conference and the number of sessions occurring simultaneously must have easily been over 10. I really liked manyof the talks and at times found it difficult to choose which rooms to go to. I missed out on a R-workshop but instead learned a lot about invasion melt down. Overall, good experience. Some key notes I took:

Data – Meta-data as always is very important when structuring datasets online, however ArcGIS data might require a more detailed description of the data presented. This is because ArcGIS is often a layered dataset will “planes” rather than “vectors” of data. The current standard is ISO-19115. This brings up another point, which is that excel is both power but maybe also problematic. Not all data fits best in excel and their may be other platforms that would be more advantageous.

Invasion theory – I learned a lot about invasion meltdown which I generally didn’t know before.  I also noticed more incorporation of theory into basing decisions about invasion. For instance, if a native+non-native grow poorer on their own than together (interspecific<intraspecific competition) this a consequence of niche differentiation theory where species use different resources. If the native+non-native grow poorer together than separately (interspecific>intraspecific competition) than this is neutral theory/co-existence. The other novel invasion talk discussed creating a metric of invasion. Although many would quickly challenge this I really do like the simplicity of the metric. I know Ontario uses a “coefficient of conservatism” to quantify a plants susceptibility to disturbance, which can be super effective in conservation management. I wonder if there were other applicable metrics we can develop to assist in restoration decisions.

Quick land assessments – The talk about REFA plus the CNPS strategy of quickly quantifying landscapes really shows how necessary this is. Coarse estimates of landscapes are such a great idea and can give great modeling power when combined together. Global datasets already exist for temperature, preciptiation, etc. However, at the local scale  ecologists can provided more refined information such as a general species composition list, topography and soil composition. If a standardized approach was used for all ecologist, this would also help with the creation of meta-data because there would be greater similarities between data sets. Lastly, I like them a lot because they are easy and can typically be done in less than half  a day.

Facilitation – I had the chance to meet with some great researchers to discuss positive interactions. It was  great experience and I got a lot of ideas from the discussions. I will do a separate post discussing the dialogue. The symposium also went very well and I thought it was a great balance of applied and theoretical that was specific enough to encourage listeners.

My talk – It went well actually. I was surprisingly nervous and it was early in the morning but still a good talk. Another one to add to the list.

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Listicle on places to publish #openscience materials & importance of a consistent persona

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Context
In publishing a dataset on figshare recently with a few collaborators, we realized that it is sometimes challenging to find each other online.  User/profile names can be misaligned quite a bit, and sometimes this can be problematic.  In opening all my various profile pages, I realized that my ‘name’ varied significantly between accounts.

To date, our team has been using the following outlets to share open-science products. Here are a two quick listicles to that end.

Outlets

figshare
slideshare
knb
researchgate
oneshare
github
youtube (lectures, conference presentations, pollinator videos)
ecoblender (lab blog or open online notebook)
dryad
peerj (pre-prints)
flickr (animal camera trap imagery)

Accounts

orcid
impactstory
researchgate
researcherID

Divergence

My name is represented in 4 different forms between outlets.  Another collaborator has 3 versions of himself online. This is just the variation between the product outlets not the recognition/aggregation profiles such as impactstory.

Please let us know if there are any fixes for this drift or if have missed any key open-science sites. Solutions we have explored include account linking, link to orcid whenever possible, & enable auto-refresh/capture by recognition accounts.

 

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