Friday, September 30, 2011

The Island of Streamertails

Are you thinking it's high time for an adventure? This next spring, after winter's deep snows and deeper thoughts, why not join me in Jamaica?

Jamaica: seabreezes, sun, misty forest, calypso––and those spectacular hummingbirds, the streamertails!

Red-billed Streamertails commonly visit Jamaican gardens.
(Photos by Peg Abbott)

We will base this week-long trip at two mountain eco-lodges, both surrounded by forest and shaded coffee plantations, and both sites lively with migrants and endemic Jamaican birds. Indeed, Jamaica has the greatest number of single-island avian endemics of any island in the West Indies––even more than its much larger neighbor, Cuba. According to World Wildlife Fund, Jamaica boasts more endemic birds than any other oceanic island in the world! That number is around 28, depending on just which splits are recognized. So, conjure up visions of Crested Quail-Doves, Jamaican Owls, Jamaican Euphonias, Jamaican Todies, Jamaican Spindalis and Yellow-billed Parrots––species found nowhere else on earth.

A delightful Jamaican Tody

World Wildlife Fund lists these endemics for Jamaica: 830 flowering plants and an additional 579 ferns; 27 reptiles; 20 amphibians; and 4 mammals including the hutia and 3 bats. Jamaica has over 500 species of endemic terrestrial snails! Of all the world's islands, Jamaica ranks 5th in the total number of endemic species it harbors.

It's a puzzle: why does Jamaica have such high levels of endemism?

Biologists have advanced several possible explanations. The island's habitats span a big elevational gradient, from sea-level coastal strand to elfin forest atop the main ridge of the Blue Mountains. Basic rock types range from limestone in the John Crow Mountains and the Cockpit Country, to igneous rocks and sedimentary shales in the Blue Mountains. Some plants are endemic to just a single limestone knoll! Conditions varied enough across the island that five distinct types of forest evolved. Complexity of soils and of vegetation supports, in turn, a more complex fauna.

Tree fern in the Hardwar Gap of the Blue Mountains

Location is also paramount. Jamaica was never connected to the mainland of Central America. But during the Ice Age when sea level was lower, three other large islands were exposed, and they provided stepping stones for island-hopping organisms. Just to the north of Jamaica, the very big island of Cuba also contributed to Jamaica's richness.

When we consider species richness, we often begin with impressive lists of the numbers of organisms for a particular place. But the true richness of a place transcends mere lists. It lies partly in the complex relationships between flora and fauna and soils, and partly in the lush, vivid sensory overload that tells us we are in the tropics.

Let's explore!

A fledgling Jamaican Owl ponders a human being.

Sunday, September 18, 2011

Rustler Park after the Burn

Recently Armando ("Mando") called a meeting in Rustler Park of 21 professionals from the US Forest Service, Arizona Game & Fish, and other agencies to assess the condition of Rustler after the Horseshoe Two Fire and to decide on the best way of encouraging its recovery. Reed Peters represented the newly-formed Friends of Cave Creek Canyon.

What they saw at Rustler surprised everyone. Normally after an intense crown fire, such as the one that roared through Rustler Park, the soil is sterilized by the high heat, and almost no plants grow for a very long time, possibly years. Even the mycorrhizae––the fungi associated with plant roots which allow seedlings to germinate––need to be reintroduced to sterilized soils. ((Usually rodents perform that service!) No one was prepared for the lush growth of wildflowers and ground cover which greeted everyone at Rustler Park, especially around the old campsites and the start of the Crest Trail.

How can botanists account for the unexpected growth? After puzzling over the situation, they settled on this theory: the backburn done about two weeks before the crown fire blazed through must have removed enough fuel that temperatures at ground level never got high enough to sterilize the soil.

Whatever allowed the strong recovery to take hold (and their theory sounds good to me!), botanists are seeing post-fire plants that they've rarely seen here, and the burnt aspen groves are surging with new growth. Reed was impressed with the number of Arizona (Ponderosa) Pines that still show green on the knoll above the campsites. Keep in mind that we've all been expecting the worst at Rustler and Barfoot Parks!

The Forest Service will remove dead trees in the campground, but will leave standing any that show green. Some of the small dead trees will be cut and left as firewood at the campsites. Workers will chip some trees, but not so many that the mulch interferes with the growth of new plants. The goal is to finish removing dead hazard trees by March, when Spotted Owls begin their nesting season. (Yes––a recent census of Spotted Owls in the Chiricahuas showed that not only do adults survive, they managed to fledge young this year as well!)

Spotted Owl (Pen & Ink by Narca)

Visitors returning to Rustler Park will, in time, see other changes. Ramadas are planned to shade the picnic tables, since so many trees were burned in the crown fire. Barfoot Lookout will be rebuilt on the same footprint. The bunkhouse will also be rebuilt. The Forest Service still has the original plans for the campground, which were developed in about the 1950s. People reviewing those plans came away very impressed with the skillfully designed layout and will respect the original work, figuring that the basic design can't be improved. Bathrooms, however, will be improved, especially to make them more accessible. Even brick-and-mortar bathrooms which are still standing will need to be rebuilt because the mortar was so weakened by the heat that they are a danger to the public.

New gates have been installed along various Forest roads, so that the roads can be closed easily whenever driving conditions are dangerous. A new route (a small road) to the Long Park gate is being considered, so that hikers will be able to bypass Rustler to reach the Long Park road even when the campground is closed.

Centaurea on the hike to Long Park (Photo by Narca)

Reed left the meeting (actually, was chased out by a hailstorm) feeling that the agencies' concern for Rustler Park and the Chiricahuas is genuine and obvious, and that great care is being taken in fostering the area's recovery, post-fire.

When will we be able to return to Rustler Park? Rumor is that the road to the top will open on September 24. I'll head up as soon after that as I can, and will post photos here of Rustler and Barfoot after the burn and after the summer monsoon. This news is encouraging!

Friday, September 9, 2011


Our friend John Roser, in his nightly patrols to see what's happening in his yard, discovered that giant Five-spotted Hawkmoths are visiting his massive flowering Datura. Since that discovery, several folks have held nightly vigils in John's yard, starting at dusk, to witness the show.

Sacred Datura unfurls its flowers each night. (Photos by Narca)

The Five-spotteds are very large hawkmoths, impressively bigger than the White-lined Hawkmoths that we frequently see here in the Chiricahua Mountains. They appear at dusk or shortly after, zeroing in on the opening white trumpets of Sacred Datura (Datura wrightii). Datura flowers grow up to 8 inches long, of a size to match the huge hawkmoths that they attract.

A Five-spotted Hawkmoth approaches a Datura flower. If you look carefully, you can see its proboscis beginning to probe the lower flower.

As the moth approaches a flower, it extends its extremely long proboscis into the bloom, then dives right in, wriggling past the pollen-bearing stamens into the flower's interior. There it turns around after a few moments and emerges, no doubt well-dusted in new pollen, which it carries to another flower.

The hawkmoth maneuvers into position, its proboscis now deep inside the flower.

Datura is in the plant family Solanaceae, and the big hawkmoth seems perfectly adapted to be its pollinator. The moth's larval food, likewise, is solanaceous plants. So here we have a good example of symbiosis or mutualism––the plant feeds the caterpillar, and when the caterpillar transforms into a giant adult, it insures the survival of the Datura by pollinating the flowers so that they can set seed.

In we go!

The Datura-diving moth quickly enters the flower and vanishes from sight.

The work of several major scientists has led to our better understanding the mutualism that binds flowers and their pollinators. Let's start with Darwin, who put forth the view that evolution (= change over time in the traits inherited by organisms) is driven by competition. However, in the view of Lynn Margulis, cooperation and mutual dependence play an even greater role. Dan Janzen focused closely on the theory of coevolution between flowering plants and their insect symbionts, based on the remarkable specializations shown by an Acacia and an ant, Pseudomyrmex ferruginea; he won the Crafoord Prize for his work in coevolutionary ecology. If the subject of pollination interests you, check out their work, as well as Gary Nabhan's book, The Forgotten Pollinators.

Yes, in the caterpillar stage these beasts are the infamous Tomato Hornworms. Since tomatoes and potatoes are also in the family Solanaceae, they fit the bill for caterpillar food quite nicely. Gardeners sometimes plant marigolds near their tomatoes to discourage the hornworms' interest.

Datura's common name, Sacred Datura, comes from its early ritual use by Native Americans. It is hallucinogenic, but a very dangerous hallucinogen. Adolescents who used the substance in initiation rites regularly died. The plant's compounds can take away vision, depress breathing, cause seizures, and bring on very high fever. Leave it to the hawkmoths!