I’ve written often here (see this, this, and this) about the tree genus Magnolia. Until very recently, everyone thought that the center of diversity of the family Magnoliaceae was Asia, and that Latin America was an evolutionary backwater with relatively few species. Only five species were known from Ecuador in 1999 (Perez 2015). Nevertheless, adventurous botanists are suddenly finding, over the last twenty years, that the unexplored mountains and forests of Latin America are peppered with rare, locally endemic Magnolia species. It now looks like Latin America may have as many Magnolia species as Asia. Ecuador alone now has at least 23 species (Perez 2015), with 17 of these new species discovered just since 2012! Our Banos-area reserves are good examples of this trend. On a single trail in our Rio Zunac Reserve, as of 2014 there were three undescribed species of Magnolia, all very rare.
The first of these three to be described was Magnolia vargasiana, published in late 2015 by Dr Antonio Vazquez, visiting from Mexico, and his colleagues. Our reserve guard, Luis Recalde, was a coauthor on that paper. Now the second species, named Magnolia llanganatensis after the Llanganates mountains, has just been published by Dr. Vazquez’ team. This time our forest guardian Fausto Recalde is one of the coauthors. Both of the Recaldes earned the honor, since they risked their livese to free-climb these tall trees to obtain the flower buds needed for their identification and description. These particular neotropical Magnolia (section Talauma, subsection Talauma) only flower at night, so flower buds have to be brought down and nurtured and watched until, at dusk, they pop open and fill our scientific station with an exotic fragrance like some imaginary tropical fruit.
We now know quite a bit more about the population of this tree, thanks to an independent study project done a few months ago by Jaelyn Bos, a student from the US who participated in the biology program of the School for International Training here in Ecuador. She and our reserve caretaker Fausto Recalde spent two weeks searching within 20 meters on either side of our trails near the known trees of this species, hoping to find more. Only four new trees was found, bringing the total to ten, in three clusters separated from each other by up to a kilometer. Strikingly, all of these trees were found in a narrow band of elevation from 1730m to 1860m. The elevation band from 1799-1820m contained seven of the ten individuals. A previous survey by John Clark, David Neill, and University of Alabama students (who found the original M. llanganatensis trees) carefully sampled a quarter-hectare of forest at 2100m elevation just up the trail from the original M. llanganatensis site, and did not find any there, though they did find two other, different new Magnolias in that higher plot. Magnolia llanganatensis thus appears to be extremely fussy about the elevation where it will grow. The two species found in the 2100m plot also seem to be hyper-specialists in a particular elevation, since no individuals of those species were found in the elevation band occupied by M. llanganatensis. This is a surprising degree of altitudinal specialization for cloud forest trees, though we see this same pattern in many of the area’s orchids and other non-woody species.
Jaelyn attempted to characterize the trees’ locations using climate and physical data, and then use ArcGIS computer software to predict where else the species might occur. Unfortunately this didn’t work, probably because of the small and highly nonrandom sample size. She also identified some of the individual Magnolia llanganatensis crowns in some aerial photos of the forest, in case their particular shade of green might be distinctive enough to identify other Magnolia crowns in the aerial photos. Unfortunately the leaves were not distinctive enough to be used for this purpose.
Jaelyn measured the trees she found. Some are canopy giants; the largest had a diameter of 59.4cm. No trees smaller than 13cm diameter were located. This may suggest that the tree is not successfully reproducing, or it could mean that the juvenile trees have leaves so different from the adults that they were not recognized by Jaelyn or Fausto. That often happens in Neotropical magnolias. In any case the tree is so rare that we are attempting to propagate it to augment the population and to get it into cultivation in botanical gardens. We have a grant from Botanical Gardens Conservation International to help us do it. We will rig the trees with climbing ropes and try to collect seeds before they are removed by predators.
Meanwhile Jaelyn and Fausto happened to find a large fallen branch from one of our big M. llanganatensis (maybe the same branch that Luis Recalde climbed to collect the original flower bud). The branch was full of capsules with ripe seeds! Some of these seeds were collected and sent to the Universidad Estatal Amazonica for propagation. I don’t yet know if they have sprouted.
Magnolias have existed as a coherent, easily recognizable group for at least 100 million years. That gives them a lot of time to move around the globe and speciate. How did this particular species end up here and nowhere else? The locally endemic orchids that inhabit the same forest belong to young genera only ten million years old at best, and we have often found sets of local species that are more closely related to each other than to distant species. In other words, in these groups, speciation is so recent that the there has not been time for dispersal beyond their original area. The local high-elevation species of the genus Teagueia are good examples; the entire group is strictly endemic to the upper Rio Pastaza watershed. So I wondered whether our two new species of Magnolia were each other’s closest relatives. Was this a local evolutionary radiation? I asked Dr Vazquez this question, and he told me that no, Magnolia llanganatensis and Magnolia vargasiana were in fact fairly distant relatives, which must have diverged many millions of years ago. I hope some day a DNA-based phylogeny of Magnolia will be constructed so we can discover some of the details of how these ancient species got here.
Because of these recent Magnolia discoveries in our Rio Zunac Reserve, and the discovery of additional new species in the lowlands immediately to the east of that reserve, our tiny little region is now considered (Perez 2015) one of the richest in the world for Magnolias (maybe THE richest, for its size)!
The research station that made these discoveries possible was built under a grant from the IUCN-Netherlands and the Netherlands Postcode Lottery. Without this station these trees would not have been discovered.
Perez Castaneda, A. J. (2015). Taxonomía y conservación de la familia Magnoliaceae en el Ecuador. Thesis, Universidad Catolica, Quito.