11 June 1999
Michael O. Dillon
Grant #5791-96: Floristic Inventory of the Bosque de
Protección
del Río Alto Mayo (San Martín,
Peru)
Botany Department
The Field Museum
Chicago, IL 60605
The second year of field work has been completed on National Geographic Society Grant 5791-96, designed to provide a floristic inventory for the forests of the Bosque de Protección del Río Alto Mayo (San Martín, Peru). Field studies in collaboration with staff from the Universidad Nacional de Cajamarca (UNC) and the Universidad Privada Antenor Orrego (UPAO) were conducted in the study area in June/July 1998.
The collecting portion of the trip yielded 280 collections of flowering plants, primarily trees, and ferns for a total of ca. 1400 individual samples. This year's collections bring the number generated by the project to approximately 1200 numbers, representing nearly 6000 individual samples. Duplicates for determination have arrived at the Field Museum, collection data were entered into a computerized database, and label have been generated from the database. Identification efforts have begun by Dr. Nancy Hensold (Field Museum Tropical Collections Specialist) and duplicates for taxonomic experts are being distributed. Photographs of habitats and plants are being scanned and a few are provided here. Localities sampled are detailed in Appendix I, and initial plant identifications and diversity figures are provided in Appendix II.
Introduction
Over the last two decades, the population of northeastern Peru has grow rapidly and this growth has resulted in the exploitation of unprotected forest resources. In 1986, amid fears that continued logging would directly threaten their watershed, local leaders in Rioja, San Martín, requested that the forests in the headwaters of the Río Alto Mayo and its tributaries be protected. The Peruvian government set aside a large portion of these forests under the protected status of Bosque de Protección Alto Mayo.
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Map showing the boundaries of the Bosque de Protección Alto Mayo, Department of San Martín, Peru. |
The Universidad Nacional de Cajamarca has an office in the Municipalidad de Rioja and Roberto Diéguez Bazán (Rioja, UNC Coordinator), transmits our results routinely to local authorities. The forests of the Bosque de Protección Alto Mayo represent 182,000 hectares and is the largest remaining tract of Selva Alta in northeastern Peru.
This, our second collecting season, beginning on 10 June 1998, a collecting team consisting of the PI (Michael Dillon, FM), Isidoro Sánchez-Vega (Director of Herbarium, UNC), Gustavo Iberico Vela (Botany Professor, UNC), José Guerra Lu (Universidad de Tingo María), Mario Zapata (Museum Assistant, UPAO) and Roberto Diéguez Bazán began work in the Rioja area. The field season was completed on 7 July 1998.
Sampling during the second season concentrated upon the forests around Laguna ONERCOCHA near Aguas Verdes and further distant localities within the boundaries of the protected forest (Appendix I). The lake is said to cover an area of over 10 hectars and to be over 50 meters deep. At 1100 meters, the vegetation at the margins is quite unlike that of surrounding "selva alta" and some elements from lower riparian habitats. The region around the lake has been largely protected from logging and it is hoped that a pollen core from this locality may tell us much about the past climate changes in the region.
In addition, we explored into Department Amazonas on the same trail from Naciento de Río Negro (a new town) to Vista Alegre, a trial that eventually leads to Molinopampa and ultimately Chachapoyas. Llewelyn Williams (see below) used this same trail on his treck to Chachapoyas in 1930. The region has largely been overcut and forest is confined to upper portions of higher slopes. From Vista Alegre to Rio Salas, the forest is very disturbed and remnants of coca production were evident. Our guide stated that in the early 1980's the region had seen a lot of activity in illegal coca but that today the area was reasonably clean.
One interesting locality within the highly disturbed central basin of the Río Alto Mayo is Morro Calzada. The Morro has been managed as a nature reserve for several years and is a frequently visited recreational area just 2 kms from the town of Calzada. For more about the Morro.
While the majority of the collections have not been identified to species, preliminary results point to high levels of diversity in several families. Provided here are the number of genera which is good indicator of diversity and the number specimens as an indicator of frequency of encounter: Rubiaceae (25 genera, 99 collections), Melastomataceae (11 genera, 63 collections), Solanaceae (13 genera, 54 collectons), Orchidaceae (10 genera, 53 collections), Piperaceae (2 genera, 43 collections) , Clusiaceae (5 genera, 41 collections), Gesneriaceae (4 genera, 36 collections), and Lauraceae (9 genera, 27 collections). These eight (8) families are responsible 35% of our collections.
When more material is identifed, we can begin comparing generic and species complements from our montane forest inventories (Dillon 1994, Dillon et al. 1995). Our collecting efforts in the Alto Mayo forests have encompassed no fewer than 114 families (Appendix II). Examples include Araliaceae, Clusiaceae, Lauraceae, Lecythidaceae, Marcgraviaceae, Melastomataceae, Myristicaceae, Passifloraceae, Rubiaceae, and Cucurbitaceae.
New species in a variety of families have been discovered and are marked in italics in the species list (Appendix II). Notable amongst the new species encountered are potential new species in Talauma species (Magnoliaceae), Styloceras (Buxaceae), Larnax (Solanaceae), and several Araceae. If the new Styloceras is conspecific with S. penninerva of Huánuco, it would mark an interesting northern disjuction in this rare species only known from the type locality.
Our collecting has also produced new records and unusual distributions.
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Facing southeast from the Mirador (ca. 2000 m) near Venceremos at the northwestern boundary of the Bosque de Protección Alto Mayo |
| View to the south from near Nuevo Tabaloso, ca. 20 km south of Rioja. Mostly cut over with only small patches of isolated and often selectively cut forest on the highest points. |
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The PI and colleagues press samples near Naciente Río Negro. |
Historical Results
In addition to the collections generated by this project, we are adding to the
database the ca. 7800 records taken from the collections made in this region
by Field Museum botanist 
Llewelyn Williams in 1929/30 (Williams 1936). Williams research was
focused on economically important lumber species and his collection vouchers are
still housed at Field Museum. Some important species, such as Swietenia macrophylla (Peruvian mahogany), were stated to have been considerably more frequent 68 years ago; we have not encountered a single individual in our collecting. Some of Williams' observations are interesting in the light of the current peril that the forest are in. Williams (p. 41, 1936) notes:
| "The exploitation of certain timbers, while not of large magnitude in relation to the extent of the forests, is progressing slowly, although handicapped by the isolation of the territory, the high freight rates, and unlike the conditins prevailing in some other tropical countries, the great distances that have to be traversed within the montaña before finding timbers suitable for market. In some instances, logs have to be floated for several hundred miles to the shipping point." |
The collecting trips and documentation began in 1996 and our data will provide yet another benchmark for this region. We have continued to visit a variety of different areas within the forest (Appendix I). The destruction of the forest continues, even though the boundaries of the protected forest are widely known. In some cases, selected large trees are removed with minimal overall damage to the forest. The heartwood is made into planks and moved by horse or oxen overland and then transported as rafts to market. Other areas are simply clear-cut without regard to future consequences. More and more, areas we sampled the previous year are found clear-cut and diversity eliminated. Population growth is expanding and a constant influx of migrants has lead to deep intrusions into the forest, where clear-cutting and planting of coffee goes unchecked.
| One important economic plant that may be in peril through habitat destruction is Carludovica palmata Ruiz & Pav. (common name: "bombonaje"), a palm-like member of the Cyclanthaceae. The fibers derived from unopened leaves are used to make the "Panama" hats famous from this area and an assortment of items for everyday use and tourist gifts. |  |
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Remnants of a recently poached tree. The trunks are cut
into boards and either hauled out by horses or oxen and rafted on tributaries
to suitable markets. |
| Raft constructed of rough-sawed planks illegally cut and readied to be floated down the river for sale in Rioja or points south along the river. |  |
 | Clear-cutting forests within the protected boundaries of the Bosque de Protección Alto Mayo. |
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Cut boards stacked to dry before transporting by mules to use or sell at market. |
 | Schefflera species [Araliaceae] |
| Close-up of Schefflera inflorescence and flowers. |  |
 | Clusia species [Clusiaceae] |
| Close-up of Clusia flower. The sticky, yellow stigma of the female flower that captures and holds the potential pollinator. |
|
 | Ocotea species [Lauraceae]. The swollen receptacle is edible by birds and wildlife when mature. The fruits which are similar to small avocados are rich in fats and oils. |
| Grias peruviana Miers [Lecythidaceae] |  |
 | Marcgravia species [Marcgraviaceae] |
| Virola species [Myristicaceae] |
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 | Passiflora species [Passifloraceae] |
| Cayaponia sp. [Cucurbitaceae] |  |
Dillon, M.O. 1994. Bosques Húmedos del Norte del Perú. Arnaldoa 2(1):29-42.
Dillon, M.O. , A. Sagástegui A. , I. Sánchez V. , S. Llatas Q., and N. C. Hensold. 1995. Floristic Inventory and Biogeographic Analysis of Montane Forests in Northwestern Peru. pp. 251-270, In Biodiversity and Conservation of Neotropical Montane Forests, The New York Botanical Garden, Bronx, NY.
Williams, L. 1936. Woods of Northeastern Peru. Fieldiana: Botany
15: 1-587.
 Localities sampled within the |
 Listing of Plant collections |
