Dwarf Forest Research Articles

Edaphic Climax Pattern of the Pygmy Forest Region of California

The dwarfed conifer forests occurring on the coastal terraces of Mendocino County, California, are oligotrophic communities containing edaphic endemics as dominants. Species distributions and community characteristics are traced along a gradient in podzolization of the soils from these pygmy conifer stands on highly weathered terrace spodosols, to redwood stands on weakly developed slope spodsols. Vegetation stature, canopy closure, species richness, litter biomass and pH generally decrease along the gradient as podzolization and nutrient impoverishment increase, whereas soil organic matter and available water capacity tend to be highest at the gradient extremes. Analyses of pygmy forest soils show low levels of macro— and micro—nutrients, and high levels of exchangeable aluminum. When ordinations of stands based on vegetational data are compared with rankings based on environmental data, changes in pH of the soil A horizon are found to correlate most highly with vegetation changes. Nutrient loss and acidification, initiated by varying rates of soil weathering in the pygmy forest region, may be aggravated, in the case of pygmy forest soils, by a series of feedback effects, including solubilization of possibly toxic amounts of aluminum by low pH, which may contribute to the observed plant stunting and shrinking pools of nutrients in the biomass. A ranking of stands along a soil nutrient gradient, based on field observations and presence data for species, correlated successively less strongly with ordinations computed by similarity—projection, Bray—Curtis method, importance—projection, principal components analysis, and factor analysis. Although these ordinations were expected to produce distortions in the interstand relations due to the modal and even polymodal nature of species response curves and to the presence of species not spanning the range of the data set, additional distortions due to variability in sample data were also highlighted.

Tree Nests of Chipmunks with Comments on Associated Behavior and Ecology

Four additional species of Eutamias ( amoenus, cinereicollis, palmeri , and ruficaudus ), added to E. minimus, speciosus , and sibericus , bring to seven the number of tree-nesting chipmunks. Tree nests were at heights of 2.6 to 23 meters. Those made of grass by E. amoenus and ruficaudus were about 30 centimeters in diameter and were used for more than one year. Most tree nests were in conifers (three in woodpecker holes), one was in a clump of young willows, and one was in a cottonwood. It is during the period of weaning and exploration just before the young disperse that tree nests are used by a mother and her family. Chipmunks appear to be the only sciurids and possibly the only rodents in which the mother and her family use both underground and arboreal nests in a given year. Feeding in the pygmy forest of bushes, chipmunks occupy a special niche between those of ground squirrels and tree squirrels.

Transpiration Rates in the Luquillo Mountains of Puerto Rico

Transpiration in elfin woodland on a peak at 1000 m and in montane rain forest at 550 m was found to be extremely low when compared to most other rates reported in the literature, regardless of habitat. Apparently, transpiration differences between the two habitats which we studied depended upon weather conditions. The extremely low saturation deficits of the air in these habitats, frequent cloud moisture deposition, and low insolation reaching the leaves because of frequent fog and closed canopy appear to be the major causes of the slow transpiration; inefficient xylem and effective scarcity of certain minerals may also be involved. Transpiration of sclerophyllous-leaved species characteristic of elfin forest was similar to that of membranaceous-leaved species from the montane rain forest. Sclerophylly appears to resist defoliation by strong mountain winds, rather than reduce transpiration as in some habitats. Inefficient base pumping due to slow transpiration, combined with mechanical wind pruning, is proposed as a major cause of tree height reduction in elfin forest. The proportionately greater stomatal area of elfin forest leaves as compared to their montane rain forest counterparts suggests that plants adapt to counteract this reduced transpiration.

A New Species of Warbler (Parulidae) from Puerto Rico

THE West Indies are among the best known of the world's tropical regions, and our knowledge of the distribution of indigenous land birds in the Greater Antilles has been thought to be nearly complete (Bond, 1956). The last new species from the Antilles were described in 19'27, the results of work in the Zapata Swamp of Cuba (Barbour and Peters, 1927) and the isolated Morne de la Selle in Haiti (Wetmore, 1927). No new species has been found in Puerto Rico in this century, and it would seem unlikely that a bird could escape detection on the island, which has a human population density now approaching 320 per square km, and less than 3,300 ha (0.4 percent of land area) of virgin forest remaining (Wadsworth, 1949). Nevertheless the discovery of extant populations of the Puerto Rican Whip-poor-will (Caprimulgus no.ctitherus) by Reynard (1962) and the Puerto Rican Plain Pigeon (Columba inornata wetmorel) by Leopold (1963), both previously presumed extinct (Bond, 1956, 1961), indicated that the inventory of the Puerto Rican avifauna might be incomplete. The largest remaining forest in Puerto Rico is in the Sierra de Luquillo at the island's eastern end. In September 1968 the senior author and his wife established residence within the forest at an elevation of 770 m, and began intensive studies of the Puerto Rican Parrot (Amazona vittata) and the Puerto Rican Tody (Todus mexicanus). These studies included a series of census routes through the forest to assess easonal and altitudinal distribution a d abundance of these and other species (Kepler and Kepler, 1970). Two census routes were established in Elfin Woodland (Figure 1), a distinctive forest type confined to the higher peaks and ridges. In this forest they occasionally noticed a warbler of peculiar appearance, but were unsure of its identity because of the difficulty of seeing small birds in this habitat. The bird (see Frontispiece) showed similarities both to the Blackand-white Warbler (Mniotilta varia), a common North American migrant to Puerto Rico, and the Arrow-headed Warbler (Den•oica pharetra), a

The Ecology of an Elfin Forest in Puerto Rico, 16. The Flowering Cycle and an Interpretation of its Seasonality

The Ecology of an Elfin Forest in Puerto Rico, 16. The Flowering Cycle and an Interpretation of its Seasonality

The Ecology of an Elfin Forest in Puerto Rico, 15. A Study of the Leafy Hepatic Flora of the Luquillo Mountains

The Ecology of an Elfin Forest in Puerto Rico, 15. A Study of the Leafy Hepatic Flora of the Luquillo Mountains

Vegetation of the Sea Cliffs and Adjacent Uplands on the North Shore of Long Island, New York

GOOD, R. E. (Dept. Biol., Rutgers Univ., Camden, N. J.) and N. F. GOOD, (Biological Abstracts, Philadelphia, Pa.). Vegetation of the sea cliffs and adjacent uplands on the north shore of Long Island, New York. Bull. Torrey Bot. Club 97: 204-208. 1970. An area of sea cliffs and adjacent uplands 7 km north-northwest of Riverhead, Long Island was studied. These cliffs range in height from 30-35 m above Long Island Sound. While most of these cliffs are very unstable and often nearly devoid of vegetation, the development of a pygmy beech forest (Fagus grandifolia) is possible in areas which remain stable for long periods. Successional stages preceding the development of this community include beachgrass (Ammophila breviligulata), little blue-stem (Andropogon scoparius), beach-heath (Hudsonia tomentosa) and pitch pine (Pinus rigida). Similar vegetational sequences take place on the adjacent uplands after destruction of the vegetation by wind blown sand.

Adaptive Aspects of Insular Evolution, A Symposium

ADAPTIVE ASPECTS OF INSULAR EVOLUTION was the theme chosen by the Association for Tropical Biology for its third international symposium, June 15-19, 1969. Appropriately enough, the symposium was held on a tropical island: at the University of Puerto Rico, Mayagiiez, where over 100 persons convened to hear presentations by an outstanding group of 17 participants assembled by Professor Ernst Mayr, Director of Harvard University's Museum of Comparative Zoology. The tone of the conference was set most effectively when Sherwin Carlquist of the Rancho Santa Ana Botanic Garden and Terrell H. Hamilton of the University of Texas broadly outlined the more important factors responsible for the characteristics of island floras and faunas, respectively. Their introductions re-emphasized how very suitable insular situations are for detailed studies of evolutionary processes, including dispersal, colonization, adaptation, competition, and extinction. With a refreshing balance of botanical and zoological viewpoints, the speakers who followed discussed various aspects of these topics and provoked considerable thoughtful and spirited debate. One of the central topics of the conference was the delimitation of some of the more important genetic and ecological characteristics of successful colonizing species. A recurrent theme was that an insular situation, be it an island or a mountain, may be remote for some species and at the same time very near for others, depending upon their ecological requirements. For certain plants, G. Ledyard Stebbins of the University of California, Davis, found that polyploidy apparently facilitates island colonization. Tremendous quantities of highly dispersible spore propagules were most responsible for the colonizing success of ferns, according to Rolla M. Tryon of Harvard University; he felt this high vagility largely accounted for the relatively low levels of endemicity characteristic of insular fern floras. Based on chromosome banding patterns, the report by Hampton L. Carson of Washington University centered upon certain genetic properties of successful species founders and subspecies colonizers in the genus Drosophila on the Hawaiian Islands. Ernest E. Williams of Harvard IJniversity reviewed his data on the invasion patterns of West Indian Anolis lizards and stressed the relation between the number of ecomorphs occurring on a given island and the structural habitats present. Carabid beetle species most successful in colonizing the West Indies were characterized by Philip J. Darlington, Jr., of Harvard University as being small, winged, and frequently associated with fresh water. Many of the talks focused directly or indirectly on the types of adaptive adjustments made to insular conditions by various floral and faunal elements following successful colonization; effects of impoverishment upon adaptive radiation, niche dimensions, and ecological and behavioral shifts were recurrent topics. Among those presenting new experimental data bearing on these phenomena were Allen Keast of Queens University, speaking on Tasmanian birds, Allen J. Kohn of the University of Washington on the carnivorous marine snail Conus, and Thomas Schoener of Harvard University on West Indian Anolis lizards. The composition, adaptations, and relationships of three very different insular floral communities were the principal subjects of Olov Hedberg of the University of Uppsala, Richard A. Howard of Harvard University, and Bassett Maguire of the New York Botanical Garden. Hedberg characterized the alpine flora of African mountains with particular reference to the rather striking adaptations to the extreme daily temperature fluctuations. Howard focused on the dwarf elfin forest of the higher elevations of Puerto Rico and the possible factors responsible for this peculiar floristic

The "Alpine" Plants of the Antilles

Although few mountains of the Antilles are over 5000 ft, some of them do possess a distinctive type of vegetation near the summit. Mountains such as Mt. Pelee, the Soufriere of Guadeloupe, or the Soufriere of St. Vincent have been active volcanoes in the present century, and the reduced scanty or restricted vegetation there may be due to past and present volcanic fumes or rapid percolation of water on ashy substrata. The reduced elfin vegetation of other mountains has been attributed to effects of persistent wind, persistent cloud cover, colder temperatures, or saturated soils. Studies of the elfin forest on Pico del Oeste (3050 ft) in Puerto Rico have supplied information on both the environment of the mountain top and the composition of the forest type. After a full year of study it was shown that the rainfall was 453 cm; that clouds enveloped the peak 100 percent of the nighttime hours and 60 percent of daylight hours with the average relative humidity 98.5 percent. Clouds supplied an additional 10 percent to the total rainfall. Wind speed raniged from 8 to 11.1 knots. The average mean temperature was 17.4 degrees C and the soil 18.3 degrees C. Growth patterns of individual plants showed an abundance of long shoot-short shoot stems; dichotomous branching and pagoda branching. Insect damage to leaves was high, reducing the photosynthetic potential of the forest. Fertility was very low as recorded in pollen viability and seed set. THE ISLANDS OF the Lesser Antilles in the Caribbean area possess volcanic cones which range in altitude from the 1950-foot St. Eustatius in the north to the 2749 feet of Mt. Catherine on Grenada in the south,

The ecology of an Elfin forest in Puerto Rico, 13. Phytochemical screening and literature survey

The ecology of an Elfin forest in Puerto Rico, 13. Phytochemical screening and literature survey

The Ecology of an Elfin Forest in Puerto Rico, 10. Notes on Two Species of Marcgravia

The Ecology of an Elfin Forest in Puerto Rico, 10. Notes on Two Species of Marcgravia

The Ecology of an Elfin Forest in Puerto Rico, 8. Studies of Stem Growth and Form and of Leaf Structure

The Ecology of an Elfin Forest in Puerto Rico, 8. Studies of Stem Growth and Form and of Leaf Structure

The Ecology of an Elfin Forest in Puerto Rico, 3. Hilltop and Forest Influences on the Microclimate of Pico Del Oeste

The Ecology of an Elfin Forest in Puerto Rico, 3. Hilltop and Forest Influences on the Microclimate of Pico Del Oeste

The Ecology of an Elfin Forest in Puerto Rico, 5. Chromosome Numbers of Some Flowering Plants

The Ecology of an Elfin Forest in Puerto Rico, 5. Chromosome Numbers of Some Flowering Plants

The Ecology of an Elfin Forest in Puerto Rico, 9. Chemical studies of colored leaves

The Ecology of an Elfin Forest in Puerto Rico, 9. Chemical studies of colored leaves

The Ecology of an Elfin Forest in Puerto Rico, 7. Soil, Root and Earthworm Relationships

The Ecology of an Elfin Forest in Puerto Rico, 7. Soil, Root and Earthworm Relationships

The Ecology of an Elfin Forest in Puerto Rico, 6. Aerial Roots

The Ecology of an Elfin Forest in Puerto Rico, 6. Aerial Roots

The Ecology of an Elfin Forest in Puerto Rico, 4. Transpiration Rates and Temperatures of Leaves in Cool Humid Environment

The Ecology of an Elfin Forest in Puerto Rico, 4. Transpiration Rates and Temperatures of Leaves in Cool Humid Environment

Avifaunal survey of Mt. Hayachine in Iwate, N. Honshu

The National Science Museum's project of biological field survey for 1967 included the avifaunal investigation of Mt. Hayachine in Iwate of which no report is published yet. The author was appointed to this and made field studies during 29 June and 4 July.The mountain, 1913m at the summit, is the highest peak of the east-west ridge. The north side foot zone is at the elevation of 600m of altitude, ascending as an extensive gradual and then steeper slope, grading from the oak zone, mixed desciduous forest, needle-leaved forest, dwarf forest, Pinus pumila to rocky zones. The south side is very abrupt near the summit and beech forest is developed on the foot zone, the lower part merging to the oak zone with some deforested parts down to 500m of altitude.Bird censuses by line transect method were made on both sides, except for the steep upper south slope (owing to rainy days) and a comparative avifaunal analyses were made. Forty four species, 42 on the north side, 28 on the south side, were recorded, and 8 species were added to Mr. Kuzu's unpublished bird list which includes winter birds. These make an total of 85 species recorded from this mountain.The north side avifauna shows a fine vertical distribution of bird species according to the forest types and was richer than on the south side where upper vertical forest divisions were lacking. The results are compared in tables and relative densities were calculated by number of birds per 1km, 1 ha, (also 40 ha for total) and 1 hour. For calculation, the highest number recorded for a same route was used, except for density per hour in which the total of numbers recorded in total census time was used. Breeding pair density was calculated for several species recorded by territory songs. Some discussions are given on factors influencing the census records. The efficiency was much better in some morning and with slow pace censuses than those of afternoon or with faster pace.Only a few birds were collected for food analysis, and a wren specimen was so distinctly darker and fully barred as to be readily distinguished from typical Honshu birds. The observation of a Turdus pallidus suggests its possible breeding unreported from Honshu. These points are left for future.

The Ecology of an Elfin Forest in Puerto Rico, 1. Introduction and Composition Studies

The Ecology of an Elfin Forest in Puerto Rico, 1. Introduction and Composition Studies