Jan 31

Friday Feast! January 31, 2014

Eating invasive species news and notes from around the internet!

Jan 25

Friday Feast! January 24, 2014

Eating invasive species news and notes from around the internet!

Jan 20

White Mulberry Bonsai

IMG_5297 - Version 2This fall Rachel Gentile researched bonsai tree art and found out that bonsais can be made from virtually any tree species! She’s been working on an invasive species bonsai tree for the past few months, and couldn’t wait any longer to share it with you. 

A bonsai is a miniature planting in a small container or tray, shaped by cutting, pruning, and wires.   I decided to make an invasive White Mulberry bonsai because even though you don’t eat a bonsai tree, this one will eventually bear fruit that can be harvested and used in recipes.  And bringing some invasive saplings indoors assures that they will not pose an invasive threat to my neighborhood.

In late fall, I collected two of the hundreds of white mulberry saplings that appear each year in the parks in Northern Virginia.  I took them back to the house and washed off all of the soil stuck to the roots.  Next, I trimmed the roots a bit so that the trees would fit into the tiny pot that I picked out.  I twisted the two tree trunks together and planted them securely in the pot with a soil mix specifically for deciduous bonsai plantings.  I made sure to pack the soil in around the roots so that there was very little movement.  I then topped the soil with a layer of top dressing stones to control moisture.

After the tree was firmly in place I twisted copper wire around the branches in order to begin shaping the tree.  I will leave the wire on the tree for about 6 months before removing it.  I also pruned it back to promote bushier growth.  After the planting and shaping, I set the tree by a sunny window and kept the soil moist.

White mulberry bonsai with training wires

White mulberry bonsai with training wires

Bonsai art is a long process, but I’ll keep you informed as it continues to grow and take shape!  I hope that someday I will have a harvest of white mulberries for a delicious invasivore recipe, but in the meantime it is serving as an interesting conversation piece when people visit my house.

Jan 13

Recipe: Sweet potato and autumn olive wine soup

If you didn’t finish your bottle of invasive autumn olive wine at your last dinner party and want a soup to keep you warm during the next polar vortex, try this spicy sweet potato soup.

Raw sweet potato and wine

Sweet potato and autumn olive wine soup

Serving Size: 2

Ingredients

  • 1 large sweet potato
  • 1/4 tsp ginger
  • 1/4 tsp curry powder
  • 1/2 tsp creole seasoning (such as Tony Chachere\'s)
  • 1 TB butter
  • 1 TB flour
  • 1 c chicken stock
  • 1/2 c autumn olive wine
  • 1/8 c half and half

Cooking Directions

  1. Peel and chop sweet potato into large chunks.
  2. Boil sweet potato chunks for 10 minutes, or until soft. Drain.
  3. Melt butter over medium heat in a saucepan.
  4. Whisk in flour to create a roux, then slowly stir in autumn olive wine and chicken broth.
  5. Add in sweet potato and spices.
  6. Reduce heat to low and simmer for 2 minutes.
  7. Use immersion blender or potato masher to blend soup until it reaches a creamy consistency.
  8. Simmer 10 more minutes.
  9. Whisk in half and half and serve.

 Sweet potato soup and wine

Jan 10

Friday Feast! January 10, 2014

Eating invasive species news and notes from around the internet!

Dec 30

Research spotlight: what triggers invasions?

Why do some species become invasive?  Research on many invasive species tells us that some particular characteristics help increase “invasability”, such as producing large numbers of offspring, being able to self-pollinate, or being able to utilize a wide variety of resources.  Another proposed reason is that changes in the local environment (temperature, food availability) may temporarily give an exotic species a large advantage, helping a species to become well-established and then invasive, whereas it was merely benign previously.  A recent study in Ecology Letters (here) utilized a thirty-year dataset to examine the question of how a change in availability of local resources or a change in the “enemies” (competitors, predators) of an invader might trigger an invasion.  This study illustrates several very important points about invasions, including: exotic species can quickly become invasive when limiting environmental factors change, and native ecosystems that are currently able to resist invasion may be less robust in the future.

Dr. Ginger Allington and colleagues studied a desert community in which an exotic annual plant called Pinweed (Erodium cicutarium) existed at low levels for twenty years, and then over just a few years, became so abundant it now dominates the ecosystem.  To determine the cause of this abrupt change, the authors needed to collect two points of evidence: they needed to demonstrate that some environmental factor limits growth of the invader (e.g. an ecological mechanism), and they needed to demonstrate that the ecological factor of interest declined or increased at the same time that the invader’s population increased.  The study took place at the Portal Project (Arizona, USA), a long term ecological experiment on (among other things) the effects of small rodents as seed predators.

Erodium flower

The authors first showed that the invader became abundant on plots from which rodents were excluded.  Meanwhile, the invader was very rare in plots where rodents were allowed, suggesting that rodents eat the seeds of the invader, limiting their population size.  In the authors’ words, “by 1984, [Erodium] had been observed on all four rodent removal plots and all four [large-bodied rodent] removal plots. In contrast, the invader did not appear on a single control plot until 1983… [and] accounted for only a small fraction of the annual plant community on these plots; E. cicutarium comprised <5% of the community on control plots for almost 20 years.”  However, in 1997, the invader population “rose rapidly and by 2007, it had become the dominant species in the annual plant community and was present on nearly every quadrat.  The increase in Erodium cicutariumon on control plots was preceded by a decline in [rodent] abundance in the early 1990s,” which occurred after several years of low precipitation.  The authors inferred that little rainfall meant that rodent population decreased (due to less food availability), and fewer rodents meant low seed predation.  This in turn allowed the invader to produce more seeds, which built up in the soil.  Subsequent return of precipitation led to a Erodium population explosion, and a shift towards an invader-dominated system.  In sum, the study thus demonstrated both a mechanism for limitation of the invader (seed predation), and an increase in the invader’s numbers when that limitation was changed.

Few long terms studies such as this one exist, and thus the mechanisms controlling invasive populations are often hypothetical.  The authors emphasize that long term study of populations is crucial to determining when, where, and how invasions will occur.

The study also suggests that a key species interaction (granivory- the consumption of plant seeds by animals) controlled the invading plant.  A management approach for invasive species might be to focus on maintaining keystone interactions in a community, to help maintain ecosystem stability and resistance to invasion.  The authors suggest that these interactions may be a more important focus than a focus on promoting high species diversity in the ecosystem (a large number of diverse species is another factor that is hypothesized to help resist invasions).

The authors close by putting their study in the context of ongoing global warming and climate changes.  In their words, “Climate models predict more frequent extreme weather events in the coming decades. The resulting increased environmental stochasticity will likely create new niche opportunities for introduced species via fluctuations in both resources and important consumers. Exotic species currently regulated by strong biotic control today may come to dominate many communities in the future.  This case study highlights the kinds of complex interactions that are difficult to predict, but that may be the root cause of the dominance of exotics.”  To predict future invasions, the authors conclude, we need better understanding of current ecological interactions, and long term monitoring.

Dec 09

Autumn Olive Taste Test

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The 2012 vintage of Invasive autumn olive wine, freshly bottled & off to the cellar for a year, waiting for this day.

It’s time to crack open our 2012 Autumn Olive Wine, and not to brag but more than a third of tasters preferred autumn olive wine to a commercial pinot grigio!

Autumn olive

The September 2012 Autumn Olive Crop

Last September, we lit out for our first collection of invasive autumn olive and came home with pounds of red and silver-flecked berries.  Sweet, a little tart, and a little bitter they turned into a delicious autumn olive jam and spectacular autumn olive thumbprint cookies.  The bulk of the berries however, were cruelly and mercilessly crushed, fermented and bottled.  It’s since been a full year, plenty of time for a sweet fruit wine to age gracefully, so we celebrate by pulling the cork, and passing the bottle.  Metaphorically, that is, since we used screw-tops.  And didn’t pass the bottle so much as do SCIENCE  with a controlled, blind taste test of 19 people I found sitting around the office.

The set-up

Our experimental taste test needed to 1) keep the taster blind to what they were drinking so they didn’t have preconceptions of a wine being made from an invasive species, and 2) have another “real” wine to compare to so they would have to seriously consider the flavors of the wine.  We accomplished both by having each taster try both the autumn olive wine and a 2012 Fish-Eye pinot grigio from California, with the identity of each hidden.  Before telling participants which wine was which, we had them write three “wine-y” words to describe each wine, mark which wine they thought was the autumn olive, and which wine they preferred.

Samples ready to be tasted! Photo credit: Heather Asiala

Samples ready to be tasted! Photo credit: Heather Asiala

The Results

The autumn olive wine compared very favorably to the commercial wine.  As a whole, this small selection of everyday people (ok fine, mostly grad-students), by no means wine connoisseurs, found autumn olive wine to be nearly as appealing and suitable as an inexpensive white wine.  The tasters most frequently described the autumn olive wine as fruity, floral, and bubbly, while the pinot grigio was described as light, sweet, and watery.  Seven of the nineteen tasters (37%) that stated a preference liked the autumn olive better than the pinot grigio.  Meanwhile, a different four of the nineteen tasters concluded that the commercial pinot grigio was probably the wine made from an invasive species!

Having persuaded our peers to subject themselves to our wine, they turned the tables and one other result emerged.  Blindfolded, the vintner himself could not correctly identify the autumn olive from the pinot grigio!

While these results are very interesting, indeed surprising, there are some caveats.  First, the Fish-Eye pinot griogio was selected based on one criteria:  it was the cheapest white wine on the shelf at the corner grocery.  Thus, it’s possible that autumn olive compares to, well, cheap wine.  On the other hand, there is clearly a market for such wine.  Second, in making the autumn olive wine in my kitchen I had free license to add as much sugar and other helpers as I wanted or needed to achieve a nice finish.  Spiking the wine in this way probably biases the comparison relative to commercial wines, which are not allowed to make these additions.  Particularly the sugar.  Nonetheless, I say make it, drink it, and let the people decide.  It seems that they like the stuff.

A word cloud illustrates bubbly, dry, fruity, and strong were among the most common words used to describe our autumn olive wine.

A word cloud illustrates bubbly, dry, fruity, and strong were among the most common words used to describe our autumn olive wine.

Autumn Olive Wine Taste Test Results Table (complete disclosure of the data from our pseudo-scientific study)

 

Taster Autumn olive (AO) descriptors Pinot Grigio (PG) descriptors Preferred Perceived Invasive
1 light, fruity, floral light, bitter AO PG
2 strong aroma, floral, bitter sweeter, woodsy, long after taste NA PG
3 sour smell, little bite, strong soft PG NA
4 very gentle nose, deep caramel color, Fruity with tangy finish fresh nose, full bodied, sharp finish NA NA
5 fruity, strong nosy, alcohol flavor, smooth NA NA
6 strong alcohol, full, too much Crisp, semi-sweet, light PG PG
7 sweet, bubbly sour, watery AO AO
8 dry, bitter not favorable AO PG
9 hint of apple, skunky finish, just ok light, airy, un-obtrusive PG AO
10 dry, tannic, open, flavorful tannic, oak finish, sour AO AO
11 dry, chemical-like, bubbly, alcoholic smooth, sweet PG AO
12 bubbly, refreshing, deceptive harsh, awful, watery AO AO
13 licorice, dry, earthy sweet, light, standard PG AO
14 soapy, tangy, bitter bland, sweet PG AO
15 bubbly, mild, floral fruity, tart, zing AO AO
16 sweet, light, tasty sweet, light, tasty NA AO
17 apple, creamy, alcoholic fruity, tangy, alcoholic PG AO
18 semi-dry, light, earthy inoffensive, boring, watery AO AO
19 bubbly, rancid, cider weak, insipid, bland PG AO

Dec 06

Friday Feast! December 6, 2013

Eating invasive species news and notes from around the internet!

Nov 15

Friday Feast! November 15, 2013

A feast of eating invasive species news and notes from around the internet!

Nov 08

Friday Feast! November 8, 2013

A feast of invasive species news and notes from around the internet!

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