New species of Malouetia (Apocynaceae): A trio from Amazonia

Three new species ofMalouetia (Apocynaceae) are described and illustrated:M. amazonica andM. pumila from Brazil andM. gentryi from Peru.Malouetia amazonica grows in inundated igapó forest, whereas the other two are found in non-inundated habitats:M. pumila incampa fechada, andM. gentryi in upland forest.     

Reproduction of the duck catfish Ageneiosus ucayalensis in a ria river system

A total of 1006 duck catfish Ageneiosus ucayalensis were collected from a ria river system of eastern Amazonia, of which 733 were females and 273 males, a sex ratio 2·69:1. Condition factors of males were higher than those of females and size at first sexual maturity (L₅₀) was 12·8 cm for females and 11·8 cm for males. The relative frequency of mature specimens and gonad condition indices indicate that the breeding season is short and coincides with the rainy season.     

Human disturbance amplifies Amazonian El Niño–Southern Oscillation signal

The long‐term interaction between human activity and climate is subject to increasing scrutiny. Humans homogenize landscapes through deforestation, agriculture, and burning and thereby might reduce the capacity of landscapes to provide archives of climate change. Alternatively, land‐use change might overwhelm natural buffering and amplify latent climate signals, rendering them detectable. Here we examine a sub‐annually resolved sedimentary record from Lake Sauce in the western Amazonian lowlands that spans 6900 years. Finely‐laminated sediments were deposited from ca. 5000 years ago until the present, and human activity in the watershed was revealed through the presence of charcoal and maize agriculture. The laminations, analyzed for color content and bandwidth, showed distinctive changes that were coupled to more frequent occurrence of fossil maize pollen. As agricultural activity intensified ca. 2200 cal. BP, the 2‐ to 8‐year periodicity characteristic of El Niño–Southern Oscillation became evident in the record. These agricultural activities appeared to have amplified an existing, but subtle climatic signal that was previously absorbed by natural vegetation. When agricultural activity slowed, or land use around Lake Sauce changed at ca. 800 cal. BP, the signal of El Niño–Southern Oscillation (ENSO) activity became erratic.     

Solute fluxes in throughfall and stemflow in four forest ecosystems in northwest Amazonia

The contribution of throughfall and stemflow as pathways for solute inputs into the forest floor in four mature forests in northwest Amazonia was investigated. Total solute inputs, resulting from the changes of atmospheric deposition after rainfall passes through the forest canopy, are presented in the form of throughfall and stemflow nutrient inputs and their possible sources are discussed. Throughfall is by far the most important solute input into the forest floor of the forests studied. On average, it represents about 98% of the total solute inputs. Although trends in solute enrichment varied among the forests, there is a general tendency in all ecosystems towards a distinct enrichment of SO₄, K, Cl, NO₃ and NH₄ in throughfall and stemflow and a small increase of protons, Mn, orthoP and Fe. When comparing the net enrichment between the forests, the relative increase of solutes in throughfall and stemflow was higher in the flood plain and low terrace than in the high terrace and sedimentary plain forests. While highest values for total cation inputs were observed in the flood plain, the low terrace showed the highest value for total inorganic anions. The length of the antecedent dry period was the main factor affecting throughfall and stemflow composition, concentrations increasing with increasing length. A second, less important factor was the amount of throughfall and stemflow, which showed a poor and negative correlation with solute concentrations. The increased activity of frugivores in the canopy during fruiting periods seemed to lead to temporary increased solute concentrations in throughfall and stemflow as a result of the wash off of deposited faecal materials and detritus in the canopy. Leaching from leaves and wash off of exudes, of solutes deposited on the foliage after evaporation of intercepted rainfall and of dry deposited materials were all found to contribute to the concentration of solutes in the throughfall and stemflow. Gross rainfall enrichment after passing the forest canopy, mainly by nutrient leaching, is considerably lower than the amounts of nutrients released in litterfall implying a tight nutrient cycling and nutrient conserving mechanisms by forests studied.     

A land cover map of South America

A digital land cover map of South America has been produced using remotely sensed satellite data acquired between 1995 and the year 2000. The mapping scale is defined by the 1 km spatial resolution of the map grid‐cell. In order to realize the product, different sources of satellite data were used, each source providing either a particular parameter of land cover characteristic required by the legend, or mapping a particular land cover class. The map legend is designed both to fit requirements for regional climate modelling and for studies on land cover change. The legend is also compatible with a wider, global, land cover mapping exercise, which seeks to characterize the world's land surface for the year 2000. As a first step, the humid forest domain has been validated using a sample of high‐resolution satellite images. The map demonstrates both the major incursions of agriculture into the remaining forest domains and the extensive areas of agriculture, which now dominate South America's grasslands.     

Multivariate mapping of spatial variation in biodiversity in Peruvian Amazonia

Abstract. Variation of biodiversity over 72 600 km² of tropical rain forest was mapped by multiple characteristics using a new combined nominal–numerical classification system. Three hundred and sixty-nine tree genera were grouped into classes by eight taxonomic, geographical, phylogenetic and ecological characteristics. Each grid cell was assigned to a nominal biodiversity type by its dominant classes and classified numerically by its share of total variation in study area biodiversity. Differentiation of 0.5° cells by nominal classification was inferior to numerical classification, but improved at higher resolution. The nominal and numerical classifications were shown to have potential for complementary roles in conservation planning.     

Diversity and host assemblage of avian haemosporidians in different terrestrial ecoregions of Peru

Characterizing the diversity and structure of host–parasite communities is crucial to understanding their eco-evolutionary dynamics. Malaria and related haemosporidian parasites are responsible for fitness loss and mortality in bird species worldwide. However, despite exhibiting the greatest ornithological biodiversity, avian haemosporidians from Neotropical regions are quite unexplored. Here, we analyze the genetic diversity of bird haemosporidian parasites (Plasmodium and Haemoproteus) in 1,336 individuals belonging to 206 bird species to explore for differences in diversity of parasite lineages and bird species across 5 well-differentiated Peruvian ecoregions. We detected 70 different haemosporidian lineages infecting 74 bird species. We showed that 25 out of the 70 haplotypes had not been previously recorded. Moreover, we also identified 81 new host–parasite interactions representing new host records for these haemosporidian parasites. Our outcomes revealed that the effective diversity (as well as the richness, abundance, and Shannon–Weaver index) for both birds and parasite lineages was higher in Amazon basin ecoregions. Furthermore, we also showed that ecoregions with greater diversity of bird species also had high parasite richness, hence suggesting that host community is crucial in explaining parasite richness. Generalist parasites were found in ecoregions with lower bird diversity, implying that the abundance and richness of hosts may shape the exploitation strategy followed by haemosporidian parasites. These outcomes reveal that Neotropical region is a major reservoir of unidentified haemosporidian lineages. Further studies analyzing host distribution and specificity of these parasites in the tropics will provide important knowledge about phylogenetic relationships, phylogeography, and patterns of evolution and distribution of haemosporidian parasites.     

小煤炱科二个新种

报道了中国小煤炱科Meliolaceae2个新种。它们是南蛇藤双孢炱负AmazoniacelastriY．X．HuetB．Songsp．nov．和乌桕生小煤炱MeliolasapiicolaY.X.HuetB.Songsp.nov.。模式标本存放在广东省微生物研究所（GDIM）。     

Post-Boom Logging in Amazonia

Recent analyses of timber exploitation in Amazonia conclude that a variety of socioeconomic and ecological factors in the region make a stable and profitable logging industry virtually impossible. Most of these studies focus on large-scale timber industries and their dependence on over-exploitation of a small number of high-value timbers. In this article we discuss the economic, ecological, and social aspects of Amazonian logging in a region where the timber industry appeared to have collapsed after stocks of high-value timber were exhausted. We show that forestry in a post-boom phase, currently found in many areas of Amazonia, differs from the better-described boom period in its scale of operations, in the range of timbers cut, in management practices employed, and in the costs and benefits of production. Results of a seven-year study show that when sawtimber, poles and firewood are produced in a management system that combines forestry and agriculture they can provide significant additional income for Amazonian smallholders.