The First Genus (Alphabetically)

Photo by Eric in SF licensed under CC BY-SA 3.0

One thing I love about orchids is that they are so diverse. One could spend their entire life studying these plants and never run out of surprises. Every time I sit down with an orchid topic in mind, I end up going down a rabbit hole of immeasurable depth. I love this because I always end up learning new and interesting facts. For instance, I only recently learned that there is a genus of orchids that has been given the unbelievably complex name of Aa.

No, that is not an abbreviation. The genus was literally named Aa. As far as I have been able to tell, it is pronounced “ah” rather than “ay,” but if any linguists are reading this and beg to differ, please chime in! Regardless, I was floored by this silly exercise in plant naming and had to learn more. I had never heard of this genus before and figured that it was so obscure that it probably contained, at most, only a small handful of species. This assumption was wrong.

Aa maderoi. Photo by Dr. Alexey Yakovlev licensed under CC BY-SA 2.0

Though by no means massive, the genus Aa contains at least 25 recognized species. A quick search of the literature even turned up a few relatively recent papers describing new species. Apparently we have a ways to go in understanding their diversity. Nonetheless, this is an interesting and pretty genus of orchids.

From what I gather, Aa are most often found growing at high elevations in the Andes, though at least one species is native to mountainous areas of Costa Rica. They are terrestrial orchids that prefer cooler temperatures and fairly moist soil. Some species are said to only be found in close proximity to mountain streams. Some of the defining features of the genus are a tall inflorescence jam packed with tiny inconspicuous, greenish-white flowers. The flowers are surrounded by semi-transparent sheaths that are surprisingly showy. All in all, they kind of remind me of a mix between Spiranthes and Goodyera.

Close up of an inflorescence of Aa maderoi showing the small, white flowers and large, semi-transparent sheaths. Photo by Dr. Alexey Yakovlev licensed under CC BY-SA 2.0

But what about the name? Why in the world was this genus given such a strange and abrupt moniker? The answer seems to be the silliest option I could think of: to be first. This genus was originally described in 1845 by German botanist Heinrich Gustav Reichenbach who recognized two species within the genus Altensteinia to be distinct enough to warrant their own genus.

According to most sources I could find, he coined this new genus Aa so that it would appear first on all taxonomic lists. There is at least one other report that the name was given in honor of a man by the name of Pieter van der Aa, but apparently this is “highly” disputed. However, all of this should be taken with a grain of salt. Though I can find plenty of literature describing various species within the genus, I could turn up no actual literature on the naming of the genus itself. All I could find is what has been repeated (almost verbatim) from Wikipedia.

So, there you have it. Not only does the genus Aa exist, it is still top of the list of all plant genera. If that truly was the goal Heinrich Gustav Reichenbach was aiming for, he certainly has succeeded!

Photos via Wikimedia Commons

Further Reading: [1]

Why Plant Relationships Matter for Caterpillars

Photo by Judy Gallagher licensed under CC BY 2.0

When it comes to caterpillars, plant diversity matters. By studying nearly 30,000 plant-caterpillar interactions across three continents (Asia, North America, and Europe), scientists have uncovered important insights into lepidopteran biodiversity in temperate broadleaf forests.

Plants and the caterpillars they host are engaged in an evolutionary arms race. As plants evolve different defenses, caterpillars evolve new ways overcoming them. As you can imagine, studying these intricate relationships can be as fascinating as it is challenging. One could easily spend a lifetime trying to understand the relationships among only a handful of species. However, by taking a step back and asking bigger questions related to evolution and herbivory, scientists have found some interesting patterns than help describe the diversity of plant-caterpillar relationships.

As one might expect, they found that as plant diversity increases, so too does the diversity of caterpillars an ecosystem can support. Many caterpillars specialize on one or only a few different host plants and these are often (though not always) within the same plant family. The reason for this has to do with plant defenses. The more closely related plants are, the more likely they are to share similar defense strategies. For instance, most milkweeds (Asclepias spp.) produce toxic compounds called cardiac glycosides and many different members of the nightshade family (Solanaceae) produce similar suites of toxic alkaloids. As a result, insects that munch on their tissues have similar hurdles to overcome in an evolutionary sense.

The more closely related plants there are in an environment, the more likely it is that the caterpillars they host can jump from one plant species to another. As a result, ecosystems that boast relatively few plant lineages support relatively few caterpillar species in part because the caterpillars they do host can more easily jump from plant species to another. The same logic applies in the opposite direction as well. Ecosystems comprised of a diversity of plant lineages limit the likelihood that any given species of caterpillar can find multiple different hosts. Because each clade of plants produces their own brand of herbivore defenses, the caterpillars hosted by each are also more likely to be different. Thus, as plant diversity goes up, so too do the numbers of caterpillar species an ecosystem can support.

Though not tested by this research, this also provides yet another example of why invasive plants harm biodiversity. Plants from other areas of the world are more likely to present novel defenses to native herbivores. If the caterpillars do not have what it takes to overcome these defenses or simply don’t recognize the plant as food, the fewer caterpillars that ecosystem can support.

Of course, none of this should come as a surprise to those interesting in native plants and gardening. The more indigenous plants you grow in and around your landscape, the more insects you can support. I also firmly believe that the results of this research are not limited to caterpillars. The same pattern likely applies to any number of plant eaters, from microbes to mammals, no matter where you look. What this research gives us are some answers to questions like “why does biodiversity matter?”

Photo Credit: [1]

Further Reading: [1]

The Flora of Antarctica: Life on a Frozen Continent

Photo by Carloszelayeta licensed under the GNU Free Documentation License.

Antarctica - the frozen continent. It is hard to think of a place on Earth that is less hospitable to life. Yet life does exist here and some of it is botanical. Though few in number, Anarctica’s diminutive flora is able to eke out an existence wherever the right conditions present themselves. It goes without saying that these plants are some of the hardiest around.

It is strange to think of Antarctica as having any flora at all. How many descriptions of plant families and genera say something to the effect of “found on nearly every continent except for Antarctica.” It didn’t always used to be this way though. Antarctica was once home to a diverse floral assemblage that rivaled anything we see in the tropics today. Millions upon millions of years of continental drift has seen this once lush landmass positioned squarely at Earth’s southern pole.

Situated that far south, Antarctica has long since become a frozen wasteland of sorts. The landscape is essentially a desert. Instead of no precipitation, however, most water in this neck of the woods is completely locked up in ice for most of the year. This is one reason why plants have had such a hard time making a living there. That is not to say that some plants haven’t made it. In fact, a handful of species thrive under these conditions.

When anyone goes looking for plants in Antarctica, they must do so wherever conditions ease up enough for part of the year to allow terrestrial life to exist. In the case of this frozen continent, this means hanging out along the coast or one of handful of islands situated just off of the mainland. Here, enough land thaws during the brief summer months to allow a few plant species to take root and grow.

Antarctic hair grass (Deschamsia antarctica). Photo by Lomvi2 licensed under CC BY-SA 3.0

The flora of Antarctica proper consists of 2 flowering plant species, about 100 species of mosses, and roughly 30 species of liverwort. The largest of these are the flowering plants - a grass known as Antarctic hair grass (Deschamsia antarctica), and member of the pink family with a cushion-like growth habit called Antarctic pearlwort (Colobanthus quitensis). Whereas the hair grass benefits from being wind pollinated, the Antarctic pearlwort has had to get creative with its reproductive needs. Instead of relying on pollinators, which simply aren’t present in any abundance on Antarctica, it appears that the pearlwort has shifted over to being entirely self-pollinated. This seems to work for it because if the mother plant is capable of living on Antarctica, so too will its clonal offspring.

By far the dominant plant life on the continent are the mosses. With 100 species known to live on Antarctica, it is hard to make generalizations about their habits other than to say they are pretty tough plants. Most live out their lives among the saturated rocks of the intertidal zones. What we can say about these mosses is that they support a bewildering array of microbial life, from fungi and lichens to protists and tardigrades. Even in this frozen corner of the world, plants form the foundation for all other forms of life.

Photo by Liam Quinn licensed under CC BY-SA 2.0

Antarctic pearlwort (Colobanthus quitensis). Photo by Patricio Novoa Quezada licensed under CC BY 2.0

The coastal plant communities of Antarctica represent hotbeds of biodiversity for this depauperate continent. They reach their highest densities on the Antarctic Peninsula as well as on coastal islands such as south Orkney Islands and the South Shetland Islands. Here, conditions are just mild enough among the various rocky crevices for germination and growth to occur. Still, life on Antarctica is no cake walk. A short growing season, punishing waves, blistering winds, and trampling by penguins and seals present quite a challenge to Antarctica’s botanical denizens. They are able to live here despite these challenges.

Photo by Gilad Rom licensed under CC BY-NC 2.0

Still, humans take their toll. The Antarctic Peninsula is experiencing some of the most rapid warming on the planet over the last century. As this region grows warmer and drier each year, plants are responding accordingly. Antarctic mosses along the peninsula are increasingly showing signs of stress. They are starting to prioritize the production of protective pigments in their tissues over growth and reproduction. Moreover, new species of moss are starting to take over. Rapid warming and drying of the Antarctic Peninsula appears to be favoring species that are more desiccation tolerant at the expense of the continents endemic moss species.

Changes in the structure and composition of Antarctica’s moss beds is far from being a scientific curiosity for only bryologists to ponder. It is a symptom of greater changes to come.

Photo Credits: [1] [2] [3] [4] [5] [6]

Further Reading: [1] [2] [3]

Saving One of North America's Rarest Shrubs

Photo by Stan Shebs licensed under CC BY-SA 3.0

The chance to save a species from certain extinction cannot be wasted. When the opportunity presents itself, I believe it is our duty to do so. Back in 2010, such an opportunity presented itself to the state of California and what follows is a heroic demonstration of the lengths dedicated individuals will go to protect biodiversity. Thought to be extinct for 60 years, the Franciscan manzanita (Arctostaphylos franciscana) has been given a second chance at life on this planet.

California is known the world over for its staggering biodiversity. Thanks to a multitude of factors that include wide variations in soil and climate types, California boasts an amazing variety of plant life. Some of the most Californian of these plants belong to a group of shrubs and trees collectively referred to as 'manzanitas.' These plants are members of the genus Arctostaphylos, which hails from the family Ericaceae, and sport wonderful red bark, small green leaves, and lovely bell-shaped flowers. Of the approximately 105 species, subspecies, and varieties of manzanita known to science, 95 of them can be found growing in California.

It has been suggested that manzanitas as a whole are a relatively recent taxon, having arisen sometime during the Middle Miocene. This fact complicates their taxonomy a bit because such a rapid radiation has led manzanita authorities to recognize a multitude of subspecies and varieties. In California, there are also many endemic species that owe their existence in part to the state's complicated geologic history. Some of these manzanitas are exceedingly rare, having only been found growing in one or a few locations. Sadly, untold species were probably lost as California was settled and human development cleared the land. 

Such was the case for the Franciscan manzanita. Its discovery dates back to the late 1800's. California botanist and manzanita expert, Alice Eastwood, originally collected this plant on serpentine soils around the San Francisco Bay Area. In the years following, the growing human population began putting lots of pressure on the surrounding landscape.

Photo by Daderot (public domain)

Botanists like Eastwood recognized this and went to work doing what they could to save specimens from the onslaught of bulldozers. Luckily, the Franciscan manzanita was one such species. A few individuals were dug up, rooted, and their progeny were distributed to various botanical gardens. By the 1940's, the last known wild population of Franciscan manzanita were torn up and replaced by the unending tide of human expansion into the Bay Area.

It was apparent that the Franciscan manzanita was gone for good. Nothing was left of its original populations outside of botanical gardens. It was officially declared extinct in the wild. Decades went by without much thought for this plant outside of a few botanical circles. All of that changed in 2009.

It was in 2009 when a project began to replace a stretch of roadway called Doyle Drive. It was a massive project and a lot of effort was invested to remove the resident vegetation from the site before work could start in earnest. Native vegetation was salvaged to be used in restoration projects but most of the clearing involved the removal of aggressive roadside trees. A chipper was brought in to turn the trees into wood chips. Thanks to a bit of serendipity, a single area of vegetation bounded on all sides by busy highway was spared from wood chip piles. Apparently the only reason for this was because a patrol car had been parked there during the chipping operation.

Cleared of tall, weedy trees, this small island of vegetation had become visible by road for the first time in decades. That fall, a botanist by the name of Daniel Gluesenkamp was driving by the construction site when he noticed an odd looking shrub growing there. Luckily, he knew enough about manzanitas to know something was different about this shrub. Returning to the site with fellow botanists, Gluesenkamp and others confirmed that this odd shrubby manzanita was in fact the sole surviving wild Franciscan manzanita. Needless to say, this caused a bit of a stir among conservationists.

The shrub had obviously been growing in that little island of serpentine soils for quite some time. The surrounding vegetation had effectively concealed its presence from the hustle and bustle of commuters that crisscross this section of on and off ramps every day. Oddly enough, this single plant likely owes its entire existence to the disturbance that created the highway in the first place. Manzanitas lay down a persistent seed bank year after year and those seeds can remain dormant until disturbance, usually fire but in this case road construction, awakens them from their slumber. It is likely that road crews had originally disturbed the serpentine soils just enough that this single Franciscan manzanita was able to germinate and survive.

The rediscovery of the last wild Franciscan manzanita was bitter sweet. On the one hand, a species thought extinct for 60 years had been rediscovered. On the other hand, this single individual was extremely stressed by years of noxious car exhaust and now, the sudden influx of sunlight due to the removal of the trees that once sheltered it. What's more, this small island of vegetation was doomed to destruction due to current highway construction. It quickly became apparent that if this plant had any chance of survival, something drastic had to be done.

Many possible rescue scenarios were considered, from cloning the plant to moving bits of it into botanical gardens. In the end, the most heroic option was decided on - this single Franciscan manzanita was going to be relocated to a managed natural area with a similar soil composition and microclimate.

Moving an established shrub is not easy, especially when that particular individual is already stressed to the max. As such, numerous safeguards were enacted to preserve the genetic legacy of this remaining wild individual just in case it did not survive the ordeal. Stem cuttings were taken so that they could be rooted and cloned in a lab. Rooted branches were cut and taken to greenhouses to be grown up to self-sustaining individuals. Numerous seeds were collected from the surprising amount of ripe fruits present on the shrub that year. Finally, soil containing years of this Franciscan manzanita's seedbank as well as the microbial community associated with the roots, were collected and stored to help in future reintroduction efforts.

Finally, the day came when the plant was to be dug up and moved. Trenches were dug around the root mass and a dozen metal pipes were driven into the soil 2 feet below the plant so that the shrub could safely be separated from the soil in which it had been growing all its life. These pipes were then bolted to I-beams and a crane was used to hoist the manzanita up and out of the precarious spot that nurtured it in secret for all those years.

Upon arriving at its new home, experts left nothing to chance. The shrub was monitored daily for the first ten days of its arrival followed by continued weekly visits after that. As anyone that gardens knows, new plantings must be babied a bit before they become established.  For over a year, this single shrub was sheltered from direct sun, pruned of any dead and sickly branches, and carefully weeded to minimize competition. Amazingly, thanks to the coordinated effort of conservationists, the state of California, and road crews, this single individual lives on in the wild.

Of course, one single individual is not enough to save this species from extinction. At current, cuttings, and seeds provide a great starting place for further reintroduction efforts. Similarly, and most importantly, a bit of foresight on the part of a handful of dedicated botanists nearly a century ago means that the presence of several unique genetic lines of this species living in botanical gardens means that at least some genetic variability can be introduced into the restoration efforts of the Franciscan manzanita.

In an ideal world, conservation would never have to start with a single remaining individual. As we all know, however, this is not an ideal world. Still, this story provides us with inspiration and a sense of hope that if we can work together, amazing things can be done to preserve and restore at least some of what has been lost. The Franciscan manzanita is but one species that desperately needs our help an attention. It is a poignant reminder to never give up and to keep working hard on protecting and restoring biodiversity.

Photo Credits: [1] [2] [3] [4]

Further Reading: [1] [2] [3] [4]

Why You Should Never Buy Cypress Mulch

Photo by Jesse Reeder licensed under CC BY-NC-ND 2.0

Gardening season is soon to be underway here in the northern hemisphere. This past weekend saw droves of people taking advantage of the nice weather by getting their hands dirty in the garden. A walk around the neighborhood brought with it a lot of smiles and a chance to reconnect with neighbors I haven't talked to in a while but it also brought with it something sinister. Lingering in the air was the scent of cypress mulch. Tons upon tons of it are being spread over gardens everywhere. One might ask "Whats the problem? Cypress mulch is more durable and more insect resistant than other mulches!"

WRONG!

Anymore today, these ideas are leftovers of a long gone era. Back when old growth cypress forests were still a thing, these centuries old trees did impart rot and pest resistance into their wood. Today, this is not the case. Because logging has taken most of the old growth cypress from places like Florida and Louisiana, mulch companies have had to resort to cutting down and mulching young, second and third growth cypress stands. Barely given the time to grow into the towering specimens their parents and grandparents once were, these young trees have not yet imparted the centuries worth of compounds into their wood that keep them from rotting and deter insect predators.

The saddest part of the cypress mulch industry is that they are destroying valuable and irreplaceable habitat for the myriad lifeforms that rely on cypress swamps for their existence. To add insult to injury, recovery of cypress trees is almost negligible anymore today due to the way we have managed our waterways. Cypress seedlings require inundation by freshwater and regular silt deposition in order to successfully germinate. A century of flood control, inundation by brackish water, as well as dam and ship canal building have completely upset this dynamic. Now, instead of building new habitat for cypress swamps, these sediments are washed away, far out into the Gulf of Mexico.

What staggeringly few people seem to care to realize is that cypress swamps are our first line of defense against hurricanes. Cypress swamps can cut the force of a storm surge by 90%. It has been estimated that the cypress swamps in Louisiana alone are worth a staggering $6.7 billion in storm protection every year. That is a lot of cash, people!

As with any other industry, the cypress mulch companies are driven by consumer demand. The simple act of individuals, communities, and local governments not purchasing this nasty product is all it will take to lessen the blow to these precious habitats. At the rate cypress is being cut, it will not take long for us to exhaust the resource entirely. As you are looking to do some gardening this year, and many years into the future, please keep these great trees in mind and stop buying cypress mulch. In lieu of wood and bark mulches, you should consider using shredded leaves from your property instead. They make excellent mulch and being locally sourced, the reduce the chances of introducing disease and other pests to your landscape. In the words of Captain Planet, "the power is yours!"

Photo Credit: Jesse Reeder (http://bit.ly/1wmQpn8)

Further Reading: [1] [2] [3] [4]






 

Hyperabundant Deer Populations Are Reducing Forest Diversity

Photo by tuchodi licensed under CC BY 2.0

Synthesizing the effects of white-tailed deer on the landscape have, until now, been difficult. Although strong sentiments are there, there really hasn't been a collective review that indicates if overabundant white-tailed deer populations are having a net impact on the ecosystem. A recent meta-analysis published in the Annals of Botany: Plant Science Research aimed to change that. What they have found is that the overabundance of deer is having strong negative impacts on forest understory plant communities in North America.

White-tailed deer have become a pervasive issue on this continent. With an estimated population of well over 30 million individuals, deer have been managed so well that they have reached proportions never seen on this continent in the past. The effects of this hyper abundance are felt all across the landscape. As anyone who gardens will tell you, deer are voracious eaters.

Tackling this issue isn't easy. Raising questions about proper management in the face of an ecological disaster that we have created can really put a divide in the room. Even some of you may be experiencing an uptick in your blood pressure simply by reading this. Feelings aside, the fact of the matter is overabundant deer are causing a decline in forest diversity. This is especially true for woody plant species. Deer browsing at such high levels can reduce woody plant diversity by upwards of 60%. Especially hard hit are seedlings and saplings. In many areas, forests are growing older without any young trees to replace them.

What's more, their selectivity when it comes to what's on the menu means that forests are becoming more homogenous. Grasses, sedges, and ferns are increasingly replacing herbaceous cover gobbled up by deer. Also, deer appear to prefer native plants over invasives, leaving behind a sea of plants that local wildlife can't readily utilize. It's not just plants that are affected either. Excessive deer browse is creating trophic cascades that propagate throughout the food web.

For instance, birds and plants are intricately linked. Flowers attract insects and eventually produce seeds. These in turn provide food for birds. Shrubs provide food as well as shelter and nesting space, a necessary requisite for healthy bird populations. Other studies have shown that in areas that experience the highest deer densities songbird populations are nearly 40% lower than in areas with smaller deer populations. As deer make short work of our native plants, they are hurting far more than just the plants themselves. Every plant that disappears from the landscape is one less plant that can support wildlife.

Sadly, due to the elimination of large predators from the landscape, deer have no natural checks and balances on their populations other than disease and starvation. As we replace natural areas with manicured lawns and gardens, we are only making the problem worse. Deer have adapted quite well to human disturbance, a fact not lost on anyone who has had their garden raided by these ungulates. Whereas the deer problem is only a piece of the puzzle when it comes to environmental issues, it is nonetheless a large one. With management practices aimed more towards trophy deer than healthy population numbers, it is likely this issue will only get worse.

Photo Credit: tuchodi (http://bit.ly/1wFYh2X)

Further Reading:
http://aobpla.oxfordjournals.org/content/7/plv119.full

http://aobpla.oxfordjournals.org/content/6/plu030.full

http://www.sciencedirect.com/science/article/pii/S0006320705001722