Flora and vegetation of the Huascarán National Park, Ancash, Peru: with preliminary taxonomic studies for a manual of the flora

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Retrospective Theses and Dissertations

1988

Flora and vegetation of the Huascarán National Park, Ancash, Peru: with preliminary taxonomic studies for a manual of the flora David Nelson Smith Iowa State University

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Flora and vegetation of the Huascarân National Park, Ancash, Peru, with preliminary taxonomic studies for a manual of the flora

Smith, David Nelson, Ph.D. Iowa State University, 1988

300N.ZeebRd. Ann Aibor, MI 48106

Flora and vegetation of the Huascardn National Park, Ancash, Peru, with preliminary taxonomic studies for a manual of the flora by

David Nelson Smith A Dissertation Submitted to the Graduate Faculty in Partial Fulfillment of the Requirements for the Degree of DOCTOR OF PHILOSOPHY Department: Botany Major Botany (Taxonomy)

Approved; Signature was redacted for privacy.

In Charge of Major Work Signature was redacted for privacy.

For the Major Department Signature was redacted for privacy.

le Graduate College

Iowa State University Ames, Iowa 1988

11 TABLE OF CONTENTS Page PART I. THE HUASCARAN NATIONAL PARK: ENVIRONMENT, VEGETATION, AND FLORA

1

INTRODUCTION

2

GEOLOGY

6

CLIMATE

17

VEGETATION OF THE HUASCARAN NATIONAL PARK

29

THE FLORA: COMMENTARY AND LIST OF TAXA

45

BIOGEOGRAPHIC RELATIONSHIPS OF THE HUASCARAN FLORA

67

BIOGEOGRAPHIC LISTS

72

PART II. PRELIMINARY STUDIES OF THE FLORA OF THE HUASCARAN NATIONAL PARK: MONOCOT FAMILIES (EXCLUDING POACEAE)

112

TO THE READER

113

MATERIALS AND METHODS

116

GENERAL KEYS TO THE FAMILIES

122

FAMILY TREATMENTS:

126

Agavaceae

126

Alliaceae

129

Alstroemeriaceae

131

Amaryllidaceae

138

Antherlcaceae

141

Bromeliaceae

143

Commelinaceae

164

Cyperaceae

167

Dloscoreaceae

193

Hydrocharitaceae

196

Iridaceae

198

Juncaceae

209

Juncaginaceae

221

Lemnaceae

223

Orchidaceae

225

iii Potamogetonaceae

253

Zannichelliaceae

2SS

LITERATURE CITED

257

ACKNOWLEDGMENTS

279

1

PART I. THE HUASCARAN NATIONAL PARK: ENVIRONMENT, VEGETATION, AND FLORA

2

INTRODUCTION The Huascarân National Park and International Biosphere Reserve is located in the Department of Ancash, Peru, immediately north of the Department of Lima. The Park occupies the major part of the Cordillera Blanca, which is the world's highest tropical mountain range, and has the highest mountain peaks in South America north of Argentina and Chile. The Park (see Map 1) is oriented northwest-southeast, has a length of 158 km, and the width varies from 11 to 39 km. The reserve has an area of 340,000 ha, and includes elevations from 3240 to 6770 meters above sea level, at the peak of Nevado Huascardn Sur. The boundaries of the Park are usually located at 3500 m, or above. The Cordillera Blanca forms part of the continental divide between western, coastal Peru and the Amazon Basin to the east. Water from the western valleys flows to the Rio Santa, and then to the Pacific Ocean, while the water from the eastern valleys flows to the Atlantic Ocean via the Amazon and Maraflon Rivers and their tributaries. The mountain building events that created the Cordillera Blanca occurred rapidly, with great uplift, and the range has been strongly eroded since uplift began (details of the geologic history and references are in the chapter on geology). These combined factors have resulted in a very steep and dissected topography with many river valleys on both the east and west sides of the Cordillera. The rough topography, extensive areas of snow and glaciers, torrential streams, and vegetation give the Park great scenic beauty. Since the last century, visitors have commented on its beauty, and in this century there have been several proposals for the creation of a Natural Park. These came to fruit in 1975, when the Huascarân National Park was established by presidential decree (ORDEZA, no date). At a later date, it was declared an International Biosphere Reserve by the UNESCO, one of the three in Peru. The western side of the Cordillera Blanca is accessible from the many towns and villages in the Rio Santa valley. Huaraz is the principal city of the valley, and the departmental capitol as well. Caraz, Yungay, Carhuaz, Recuay, and Catac are also cities of regional importance. The Rio Santa valley is readily accessible via a paved road from the coast. There is direct bus service from Lima to Huaraz and Caraz, serving all the major towns in the valley. The eastern side of the Cordillera is less readily accessible; there is a gravel road crossing the Cordillera between Catac and Chavin, which continues northward around the Park via Pomabamba, with connection to the Rio Santa valley. More or less regular bus service is available on that route.

MAJOR PEAKS

40 s

8*50 S

ALTITUDE*

1 Champara Este 2 Mllluacociia 3 Pucahirea Noite 4 Santa Cniz Sur 5 Caraz 6 HuandoyNorte 7 Chacraraju 8 Huascaran Sur 9 Contraheirbas Central 10 Hualcan Norte 11 CopaSur 12 Palcaralu Este 13 CMnchey 14 Huantzan 15 Uruashraju Norte 16 Morron]u 17 Rarla Norte 18 Caullaraju

5750 m 5480m 6050 m 6260 m 6025m 6395m 6075 m 6770 m 6040 m 6125 m 6190 m 6275 m 6220m 6395m 5720 m 5710 m 5580m 5690m

*Altitude rounded to nearest S m. Sources: Bartie (1981) and DIaz Bustos (1984)

ry YUNGAY @"10 S

CARHUAZ 9'20"S +

Ishinea

*"30 S HUARAZ

w

CARHUAZ 9®20'S +

Ishinea

4

HUANTAR 9*30 s

9*40 s RECUAY

CATAC

9"50 S

HUASCARAN NATIONAL PARK ANCASH, PERU Park Boundary Continental Divide Major Road Departmental Capital o Town ^ Major Mountain Peaks A Approximate Scale: 0 k — 2 5k m Adapted from ORDEZA (no date) and Diaz Bustos (1984) Map 1. Huascarân National Park

LA UNION

10*00 S

CONOCOCHA CHIQUIAN LIMA

4 The Park has considerable economic importance. It is the largest Peruvian National Park within easy access of Lima; the pleasant climate of the Rio Santa valley and the spectacular scenery attract a large number of tourists, domestic and foreign, to Huaraz and the adjoining Park, making tourism a major regional industry. The principal activities of the visitors to the Park are sightseeing, nature watching, hiking, and mountain climbing. Expeditions come from all parts of the globe to enjoy the world class climbing afforded by the many glaciers and peaks in the Park, of which 26 have an elevation of over 6000 m. Scientifically, the Reserve offers many possibilities for study in a variety of fields, for example, meteorology, geology, glaciology, botany, limnology, zoology, ecology, and park, range, and wildlife management. The Cordillera Blanca is interesting for a number of factors, including its high elevation, wide range of habitats and microsites, climatic extremes, biogeographical position and connections, and its size. Its possibilities as an outdoor laboratory are immense, and it is representative of much of the tropical Andes in terms of environmental conditions and biotic elements. There are several reasons for embarking on a floristic study of the Huascaràn National Park: — The Andes are the largest continuous mountain range in the tropics, and the only one which is oriented north-south. The continuity of the chain is offers excellent opportunities for plant migration, yet the highest elevation habitats are not physically contiguous. There is a delicate balance between the potential for dispersal and factors of isolation; it is an excellent natural laboratory for evolution. And, the isolating factors may be large scale, such as the Huancabamba depression (Berry, 1982), or small scale, such as the difficulties of gene flow between small populations separated by local topography. — The bulk of studies on high Andean plants have been done in the Andes north of the Equator; the Cordillera Blanca is in the Southern Hemisphere. — The Huascaràn florula is the only complete, recent study of the high elevation vegetation of Peru. It is representative of a large portion of the Peruvian high mountain region, and comparisons will now be possible between the floras of western Cordilleras of Peru and those of the eastern Cordilleras. This florula also offers a unique comparison with earlier floristic studies in the Andes, and with the floristic studies in other equatorial high elevation regions.

5 — Biogeographically the Cordillera Blanca is just between the southernmost extension of vegetation related to the paramos in the western cordilleras of the Andes and the northernmost extension of the puna. — A florula of the Huascarân International Biosphere Reserve has practical value as a basic tool in management and for future scientific research, and it is a logical extension of the Missouri Botanical Gardens' scientific activities in Peru. In late 1984, the Missouri Botanical Garden began a study of the flora of the Huascarân National Park, with the objectives of cataloguing the flora and, as such, creating a data base on the flora of the Park, creating an on-site herbarium as a resource for resource managers, scientists, and other persons interested in the flora, in-field training of Park personnel in field botany, and preparation of a manual to the flora. The field work was completed between December 1984 and August 1986, during which time 3843 specimen sets were collected, forming the base for the study of the Park flora. Herbarium study has been in progress since September 1986. The results of that study are reported here, as well as preliminary taxonomic studies in preparation for the manual of the flora.

6 GEOLOGY The Pacific Ocean is rimmed by a tectonically and orogenically active arc of mountains and volcanic islands (Zeil, 1979). The Andes are composed of several volcano-plutonic chains (Cobbing, 1978; Sillitoe, 1974), which extend along the western edge of South America from northern Venezuela and Colombia to southern Chile and Argentina, and are part of the circumpacific mountain system. This does not imply that the tectonic events and mechanisms are uniform throughout the circumpacific system, nor on a larger, global scale (Cobbing and Pitcher, 1972). At present there are three models for mountain building: collision of continental plates, continental uplift by an underthrusting oceanic plate, and the Andean model (Cobbing and Pitcher, 1972). The Andean model involves convergence of a continental and an oceanic plate and the subduction of the oceanic plate, but due to the relative thicknesses of the two plates, the thin oceanic plate is unable to bend or lift the thick continental plate (Cobbing and Pitcher, 1972; Myers, 1974, 1975). In the process of the Andean orogeny, the oceanic plate pushed against the continental South American plate, which fractured into narrow strips of crust parallel with the plate margin and these reacted tectonically by moving up and down along vertical fractures (Myers, 1974, 1975). The fractures represent major fault lines in the crystalline, Precambrian basement rocks, and possibly shear zones in the crust (Cobbing and Pitcher, 1972; Myers, 1975; Pitcher and Bussell, 1977). These ancient lines have determined the course of sedimentation, deformation, magmatism, and mineralization from the Mesozoic to the present (Myers, 1975; Pitcher and Bussell, 1977). Much is left to study regarding the orogenesis and tectonic history of the Andes, and not all students of the problem are in accord; James (1971, 1973) maintains that an underthrusting oceanic plate is causing the uplift. The Andes system is differentiated longitudinally into a series of parallel cordilleran systems of different ages, lithology, and history, and is divided along its length into distinct tectonic segments recognizable by surface and structural features, vulcanism, geophysical evidence, and tectonic boundaries (Hall and Wood, 1985; Sillitoe, 1974). The Central Andes of Peru between Huancabamba and Pisco are within a single, volcanically quiet tectonic segment (Hall and Wood, 1985; Sillitoe, 1974), and are divided into two Cordillera systems, the younger, western Cordillera Occidental and the older, eastern Cordillera Central, which are separated by the Rio Marafion. In Ancash, the

7 Cordillera Occidental is further divided into the Cordillera Negra, the Rio Santa valley, and the Cordillera Blanca (Wilson et al., 1967). Regional Geologic History

This account follows Wilson et al. (1967), except when) noted. The Precambrian and Early Paleozoic strata were formed by marine géosynclinal deposition, which ended in the Early Paleozoic with a period of orogenesis, including intrusion of plutonic rocks and metamorphosis. The Andes have continued to be an active orogenic belt at intervals throughout Phanerozoic time (Cobbing, 1972). The period of mountain building was followed by a long period of erosion. In the Devonian, a series of major sedimentation basins were formed, controlled by the long established underlying fault structure and parallel with the directional trend of the Andes (Pitcher and Bussell, 1977). The Mississippian to early Permian was a period of deposition characterized by alternating marine submergence and continental emergence. The region was emerged and continental throughout the Pennsylvanian, and submerged and marine during the early Permian. Continental masses have been in movement relative to each other throughout the earth's history. At the end of the Palaeozoic Era, the palaeocontinents Laurasia and Gondwana came into contact forming Pangaea. This "supercontinent" lasted from the late Carboniferous to the early Jurassic. It was, however, not a static landmass, but in a process of constant change (Irving, 1977). Pangaea began to separate into North America, Eurasia, and Gondwana in the late Jurassic, and Gondwana began to separate into South America, Africa, Australia, Antarctica, and India about the same time as the separation of Pangaea. Historically, the western margin of West Gondwana, present day South America, was tectonically quiet (James, 1971). Beginning in the middle to late Permian, major tectonic activity began, and by the early Mesozoic Era the eastern Pacific subduction zone was functioning (James, 1971; Zeil, 1979). Cobbing (1976) places the beginnings of the eastern Pacific subduction zone in the early Jurassic. This was followed by elevation and continental deposition in the middle to late Permian. In the early and middle Triassic, the region was emerged slightly above sea level, and suffered little erosional destruction, becoming a stable erosion surface, which subsided to marine deposition in the late Triassic-early Jurassic. In the upper Jurassic, the region was emergent, although little above sea level, and lightly eroded.

8 During the Cretaceous, the major features of northern Peru were the Eastern and Western Peruvian geosynclines separated by the MaraAon geanticline. The Tapacocha fault is the axis and most important tectonic line of the Western Peruvian geosyncline (Myers, 1975), although Cobbing (1978) considers the Cordillera Blanca fault to be the most important, and the Rio Santa basin was a miogeosyncline on the Chavin crustal block between the Cordillera Blanca and Tapacocha faults (Myers, 1975). West of the Tapacocha fault, the underlying blocks subsided faster than the blocks east of the fault and a eugeosyncline formed over the Paramonga and Paracas crustal blocks (Myers, 1974, 1975). The Early Cretaceous was, largely, a period of subsidence (Myers, 1974), during which the western geosyncline was alternately slightly elevated and slightly subsided, a site for shallow water deposition and marine invasion. In the Early Cretaceous, sea floor spreading of the South Atlantic initiated (James, 1973) and West Gondwanaland began to separate into Africa and South America. By the late Cretaceous, the western geosyncline was uplifted, and the region has remained continental to the present. This initial phase of orogenesis completely disrupted the paleotectonic units. With uplift, the region went through a period of deformation, and was strongly folded by decollement (Myers, 1975) with the formation of several thrust fault systems. The deformation is especially evident in the Jurassic and Cretaceous sedimentary series. The mountain building events, which continue to the present, were initiated in the Tertiary with large scale block-faulting, uplift, and volcanic and plutonic igneous activity, including the formation of the batholiths of the western cordillera. The tectonic and magmatic events occured in stages, rather than continuously (Noble et al., 1974). The great Coastal batholith formed early in the period, and the Cordillera Blanca batholith much later (Cobbing, 1978). In the late Miocene-early Pliocene, the region was extensively eroded, and the "puna" erosion surface formed. A renewed period of uplift was initiated in the Pliocene and Pleistocene, and possibly as early as the late Miocene. The "puna" erosion surface was uplifted about 3000 meters to an average elevation of 4200 meters above sea level. This uplift was a two stage event; the first stage elevated the "puna" surface 1000 meters and initiated a period of deep erosion known as the valley stage, whereas the second stage elevated the "puna" surface an additional 1000-2000 meters, and initiated the canyon erosional stage, which was stronger than the valley stage. The effects of these two erosion stages are evident in the regional geomorphology. Since the "puna" erosion surface was extensively faulted, uplift was uneven and many blocks were raised to

9 greater heights. The Cordillera Blanca was raised about 2000 m heigher than the bulk of the "puna" erosion surface. The Andes were extensively glaciated in several events during the Pleistocene and Recent time; this is discussed in the section on glaciology. Sedimentary and Volcanic Stratigraphy

The lowermost strata exposed within the Park are Jurassic in age, and the youngest are Quaternary and Recent sediments. The following is an overview of the geologic column, based on the works of Benavides-Câceres (1956), Coney (1970), Wilson (1963), and Wilson et al. (1967). The distribution of the formations is shown on Map 2. Upper Jurassic: Chicama formation (Js). A very thick formation with a complicated structure (regional decollement), composed of dark gray shales with bands of fine, silty sandstones, it was deposited under reducing conditions in a deep marine environment. Both the Jurassic and the Cretaceous were major sedimentary periods, and the weight of the sediments resulted in about 3000 meters of subsidence (Wilson, 1963). The Cretaceous rocks can be divided into a lower group that is basically nonmarine, clastic sediments, the Goyllarisquisga Group, and an upper group of basically marine calcareous sediments, represented here by the Parihuanca Formation alone (Wilson, 1963). The clastic materials forming the Cretaceous sedimentary series probably came from the MaraAon geanticline. These sediments were strongly folded during the Tertiary. Lower Cretaceous: Goyllarisquisga Group (Ki). Wilson (1963) named this group, which includes the pre-Albian Cretaceous units from north and central Peru. Cobbing et al. (1981) found the concept useful, although they disagreed with his interpretation of the stratigraphie relationships, including only the Carhuaz and Farrat Formations in the group. This Group has three facies, an eastern, southern, and western, the western is the thickest and most varied. It is represented within the Park by four formations: (1) Chimu Formation: This formation is relatively thin (150-400 meters deep). The lower layers are composed of brown sandstones and quartzites intercalated with bands of dark gray, silty, carbonaceous shale and coal. The sandstone predominates over the shales in a ratio of about 10:1 (Coney, 1970). The coal is often present in thin bands, but can occur in veins up to 2 meters thick. The upper layers are grayish white quartzite. The formation was deposited in delta and floodplain environments. (2) Santa Formation; Also relatively thin, this has a lower layer of dark gray shales and an upper layer of sandy oolytic limestone. Deposition occurred in littoral and near shore marine environments. The strata weather to a brown color.

HUASCARAN NATIONAL PARK GEOLOGY Faults: thrust observed Inferred Approx. Scale: 0 25 Km Adapted from Instituto de GeologIa y MInerIa (1875)

QUATERNARY: O Qc

Quaternary Sediments

TERTIARY: B TsQv Ti B T-v

B

Yungay Formation Cordillera Blanca Batholith Callpuy Formation

CRETACEOUS: EI KTI-C Kms M

B B JURASSIC: B Js

Huaylas Formation Parlahuanca Fonnation Qoyllarisqulsga Group Chicama Formation

2. Huascaràn National Park: Geology

11