Lowland Amazonian Forests Research Articles

The Condor Bioreserve in Ecuador

The tropical Andes region has extraordinary biological diversity with considerable endemism. The complex topography, climate, geology, and biogeographic history of the Andes have helped create a high turnover in species over distance and along steep environmental gradients. The humid montane and premontane forests of the tropical Andes compete with the lowland Amazonian forests in species richness. Long-term maintenance of diversity in the tropical Andes requires a management strategy that takes account of landscape patterns. Especially in heterogeneous regions such as Andean forests, management of the landscape is more appropriate for biodiversity conservation than management of local sites.

Pollination of Bactris (Palmae) in an Amazon Forest

Phenology, inflorescence behavior, and pollination of 10 sympatric taxa ofBactris were studied in a lowland Amazon forest. Taxa flowered over an eight month period during the rainy season and early dry season, but individual taxa flowered for one to a few months. Related taxa had mostly non-overlapping flowering periods. Inflorescence behavior was similar for all taxa, with nocturnal pistillate anthesis and temperature elevation, followed 24 hours later by rapid, nocturnal staminate anthesis. Pollinators of all taxa were small weevilsPhyllotrox (Curculionidae) and nitidulidsColopterus (Nitidulidae), although various other insect visitors were recorded. Large numbers ofPhyllotrox were recorded on inflorescences, but weevil sex ratios were highly skewed.

Effects of Soil Texture on Belowground Carbon and Nutrient Storage in a Lowland Amazonian Forest Ecosystem

Soil texture plays a key role in belowground C storage in forest ecosystems and strongly influences nutrient availability and retention, particularly in highly weathered soils. We used field data and the Century ecosystem model to explore the role of soil texture in belowground C storage, nutrient pool sizes, and N fluxes in highly weathered soils in an Amazonian forest ecosystem. Our field results showed that sandy soils stored approximately 113 Mg C ha-1 to a 1-m depth versus 101 Mg C ha-1 in clay soils. Coarse root C represented a large and significant ecosystem C pool, amounting to 62% and 48% of the surface soil C pool on sands and clays, respectively, and 34% and 22% of the soil C pool on sands and clays to 1-m depth. The quantity of labile soil P, the soil C:N ratio, and live and dead fine root biomass in the 0–10-cm soil depth decreased along a gradient from sands to clays, whereas the opposite trend was observed for total P, mineral N, potential N mineralization, and denitrification enzyme activity. The Century model was able to predict the observed trends in surface soil C and N in loams and sands but underestimated C and N pools in the sands by approximately 45%. The model predicted that total belowground C (0–20 cm depth) in sands would be approximately half that of the clays, in contrast to the 89% we measured. This discrepancy is likely to be due to an underestimation of the role of belowground C allocation with low litter quality in sands, as well as an overestimation of the role of physical C protection by clays in this ecosystem. Changes in P and water availability had little effect on model outputs, whereas adding N greatly increased soil organic matter pools and productivity, illustrating the need for further integration of model structure and tropical forest biogeochemical cycling.

Patterns of Activity, Flocking, and Habitat Use in Parrots of the Peruvian Amazon

We explored patterns of flight activity, flocking, and habitat use in a diverse community of parrots in an Amazonian lowland forest. Parrots were most active just after sunrise with a second peak of flight activity following a mid-day lull. Brotogeris spp. were exceptional, being most active in the early afternoon. Among the nine genera studied, we observed marked differences in where the birds flew relative to the canopy. Body size was a poor predictor of flight height, although it was strongly and inversely correlated with flock size. Most parrot species flew in groups of one to four individuals, suggesting that mated pairs are stable and that family groups remain together post-fledging. Flocks were exclusively monospecific except when the birds were foraging in trees or eating soil at clay licks. These forest-dwelling parrots did not show dramatic increases in flock size in the evening, reflecting the lack of communal and multispecies roosting observed in other parrots. Generally, the large- and mid-sized species of parrots were associated with high-ground forest, whereas smaller species favored transitional forest. Because daily ranging patterns for these parrots potentially include all habitats, these patterns of habitat use suggest selection for subtle differences among forest types. As expected, smaller species were less detectable at a distance than large species. Comparisons of size and detectability indicate that macaws can be reliably counted to a distance of 300 m, but 100 m may be more appropriate for the smaller and low-flying genera. In sum, we found that observing parrots from the canopy is a useful method for quantifying parrot activities in a closed-canopy system, and that these forest-dwelling parrots are markedly less social than their counterparts on islands and in more open habitats. Patterns of flight behavior, habitat preferences, and the body size to flock size relationship invite further studies on the roles of predation and resource availability in the structuring of parrot communities.

A New Species of Aldina (Fabaceae: Caesalpinioideae) from Venezuelan Amazonia

Aldina paulberryi (Fabaceae: Caesalpinioideae), a new species from Amazonian lowland forest, is described and illustrated, and its relationship with A. reticulata is discussed. Aldina paulberryi Aymard, sp. nov. TYPE: Venezuela. Amazonas: Rio Orinoco, cerca de Macuruco, bosques h6medos, 200 m, 3 Mar. 1976, P Berry 2125 (holotype, VEN; isotypes, MO, NY). Figure 1. A. reticulatae R. S. Cowan affinis, sed ab ea foliolis late ovatis vel orbicularibus, venatione tertiaria inconspicua usque obsoleta, petalis 5, 1-1.5 cm longis, filamentis 56 mm longis, antheris 4-5 mm longis; ovario lineari-elliptico, 2-4 mm longo, stylo ca. 3 mm longo, stipite 2-5 mm longo diversa. Tree 15 m tall; branches and branchlets densely yellow pubescent, becoming glabrous when mature. Leaves 3-foliolate or the uppermost 1-foliolate, alternate; petioles ca. 5 cm long, densely yellow pubescent, becoming glabrous when mature, petiolules 1-2.5 cm long, densely yellow pubescent, articulate at apex; leaflets chartaceous to subcoriaceous, broadly ovate to orbicular, 7-15 cm long, 6-14 cm wide, the base acute to subcordate, the apex obtuse, margins subrevolute, entire, glabrous on the upper surface, yellow appressed-pubescent on the lower surface, more densely so on the midrib and secondary nerves, becoming glabrous and graygreen when mature, secondary nerves conspicuous, 7-13 on each side, tertiary venation inconspicuous to obsolete. Inflorescence axillary, simple, 7-19flowered, 11-19 cm long, densely yellow appressed-pubescent, becoming glabrous when mature. Flowers pedicellate, pedicels 2.5-5 mm long, articulate at the base, densely yellow appressedpubescent; calyx entire in bud, opening apically, hypanthium 1-1.3 cm long, densely yellow appressed-pubescent, sepals 3 or 4, 4-5 mm long, 25 mm wide, ovate, densely yellow appressed-pubescent externally, glabrous internally; petals 5, 11.5 cm long, white, obovate, unguiculate at the base, glabrous on both surfaces; stamens 30-40, white, uniform, connate at the base, filaments glabrous, 5-6 mm long, anthers glabrous, linear, dorsifixed, 4-5 mm long; ovary linear-elliptic, striate, 2-4 mm long, densely yellow pubescent, style glabrous, ca. 3 mm long, stipe densely yellow pubescent, glabrous at the base, 2-5 mm long, stigma terminal, fruit obovoid, ca. 2.5 cm long, woody, 1seeded. (Fig. 1.) Distribution and ecology. Known only from the type locality, where it has been collected in lowland humid forest. Aldina paulberryi is most closely allied to A. reticulata Cowan, from Venezuelan Amazon montane forests (Cowan, 1953, 1961), but differs in having leaflets broadly ovate to orbicular, tertiary venation inconspicuous to obsolete, 5 petals 1-1.5 cm long, filaments 5-6 mm long, anthers 4-5 mm long, ovary linear-elliptic, 2-4 mm long, style ca. 3 mm long, and stipe 2-5 mm long. In contrast, A. reticulata is characterized by leaflets oblong to oblong-ovate, tertiary venation strongly reticulate, 4 petals ca. 2.5 cm long, filaments ca. 1.5 mm long, anthers ca. 7 mm long, ovary oblong-ovate, 4-5 mm long, and style 3-6 mm long. This species is named in honor of Paul E. Berry for his significant contributions to our knowledge of the flora of the Venezuelan Guayana. Acknowledgments. I thank Kay Yatskievych (MO), David Neill (MO), and James Zarucchi (MO) for valuable comments and observations on the manuscript. I am grateful to Roy Gereau (MO) for revising the Latin diagnosis, to Robert Magill (MO) and the Missouri Botanical Garden staff for making their facilities available for my research, and to Bobbi Angell for preparing the illustration.

Reproductive health in couples with sterility and aborted pregnancies living in a territory with radionuclide contamination

In the context of multiple forest management, multipurpose tree species which provide both timber and non-timber forest products (NTFP), present particular challenges as the potential of conflicting use for either product may be high. One key aspect is that the magnitude of conflict of use can be location specific, thus adding complexity to policy development. This paper focuses on the extent to which the potential for conflict of use in multipurpose tree species varies across the Amazonian lowland forests shared by Peru, Bolivia, Colombia, Ecuador and Venezuela, emphasizing the economic dimension of conflict. Based on a review of the current normative and regulatory aspects of timber and NTFP extraction in the five countries, the paper also briefly discusses the opportunities and constraints for harmonization of timber and NTFP management of multipurpose species across the region. It was found that about half of the 336 timber species reviewed across the five countries also have non-timber uses. Eleven timber species are multipurpose in all five countries: Calophyllum brasiliense, Cedrela odorata, Ceiba pentandra, Clarisia racemosa, Ficus insipida, Jacaranda copaia, Schefflera morototoni, Simarouba amara and Terminalia amazonia. Seven other multipurpose species occurred only in either Venezuela (Tabebuia impetiginosa, Spondias mombin, Pentaclethra macroloba, Copaifera officinalis, Chlorophora tinctoria, Carapa guianensis) or Ecuador (Tabebuia chrysantha). Four multipurpose tree species presented the highest potential of conflict of use across the region: Dipteryx odorata, Tabebuia serratifolia, Hymenaea courbaril and Myroxylon balsamum yet these were not evenly distributed across all five countries. None of the five studied countries have specific legislation to promote sustainable use of any of the multipurpose species reported here and thus mitigate potential conflict of use; nor documented management options for integration or else segregation of both their timber and NTFP values.

Neotropical Mammals and the Myth of Amazonian Biodiversity

Data were compiled on the distribution of mammal taxa (883 species, 242 genera, 45 families, and 10 orders) among South America's six major macrohabitats: lowland Amazon forest, western montane forests, Atlantic rain forest, upland semideciduous forest, southern mesophytic forest, and drylands. The drylands are the richest area in numbers of species supported and are more diverse than the other habitats, including the lowland Amazon rain forest, when endemics are considered. An analysis of number of endemic and nonendemic taxa versus size of area found a simple positive linear relationship: the drylands, almost twice as extensive as the Amazon lowlands, support more endemic taxa. Conservation plans that emphasize the wet tropics and fail to consider the drylands as special repositories of mammal diversity will be unable to preserve a significant number of novel taxa.

MtDNA PHYLOGENY OF ANDEAN MICE: A TEST OF DIVERSIFICATION ACROSS ECOLOGICAL GRADIENTS.

Parapatric speciation across sharp ecological gradients is an alternative to the more usual allopatric model as both a general explanation of organismal diversification and as an explicit statement regarding differentiation of tropical forest biotas (Endler, 1977, 1982a, 1982b). The relevance of this model to species of small mammals distributed across a 3,000 meter gradient on the eastern flank of the Peruvian Andes is examined here by phylogenetic analysis of comparative mitochondrial DNA sequences, relying on both freshly collected samples and extracts taken from skins preserved in museum collections. These analyses falsify the applicability of the gradient model in this case. Moreover, the phylogenetic approach employed here provides an explicit test of the feasibility of the gradient model for any other taxon, either plant or animal, of the lowland Amazonian forest.

System propulsion of an Amazonian lowland forest: an outline

The study presents an outline of the systems analysis of the terre firme lowland forest N of Manaus, Brazil. The study deals with the water and element cycles, with litterfall and decomposition, and makes some points on the root-mat zone, the heart of the tropical forest system. Emphasis is also given to studies on the physical and chemical background of the loatosolic sediments around Manaus which mainly form the matrix of the terra firme forest in this particular area.

Ecology and Population Dynamics of the Pygmy Marmoset, Cebuella pygmaea

The pygmy marmoset population of a 3-km2 sample area of Amazonian lowland forest was censused and monitored intensively between September 1976 and January 1978. Floodplain forest constituted the habitat of Cebuella and supported a population density of 51.5 independently locomoting individuals (ILI) per square kilometer. The highest population concentration occurred along the edges of the river, where the density reached 274 ILI per km2. Adults comprised about one half of the total population. About 83% of the population lived in stable troops; the remaining 17% was made up by incipiently associated pairs and solitary individuals. Stable troops were made up of 1 breeding female, her mate, and her maturing offspring of up to four successive litters. Moreover, some troops contained 1-2 additional adult members. Troop size ranged from 2 to 9 ILI, with a modal size of 6 ILI. The births showed two annual peaks and the interbirth intervals ranged between 5 and 7 months. Infant survival was about 67%. Exudates (sap and gums) of trees and vines, insects and arachnids constituted the principal food resources of the population. The troops occupied exclusive home ranges of 0.2-0.4 ha. Several troops changed home range sites temporarily or permanently in the course of the study.