Charles E. Zartman

HABITAT FRAGMENTATION IMPACTS ON EPIPHYLLOUS BRYOPHYTE COMMUNITIES IN CENTRAL AMAZONIA

Tropical deforestation is a progressive process resulting in the conversion of rain forest into a mosaic of mature forest fragments, pasture, and degraded habitat. Understanding the long-term effects of habitat fragmentation on tropical plant community structure is critical to predicting how alterations to the landscape will impact tropical biodiversity. The objective of this study was to examine fragmentation effects on the composition, abundance, and species richness of epiphyllous (leaf-inhabiting) bryophytes. I conducted this research in an experimentally fragmented forest reserve in central Amazonia where data on the distribution and abundance of 65 bryophyte taxa were analyzed from 16 1-ha sample plots located in continuous forest and fragments. Epiphyll communities inhabiting small (1- and 10-ha) fragments exhibited lower species richness, abundance, and among-site compositional variation than those from 100-ha fragments and continuous forest plots. Reduced epiphyll diversity in small fragments is ...

Metapopulation Extinction Thresholds in Rain Forest Remnants

Although habitat fragmentation is a major threat to global biodiversity, the demographic mechanisms underlying species loss from tropical forest remnants remain largely unexplored. In particular, no studies at the landscape scale have quantified fragmentation’s impacts on colonization, extinction, and local population growth simultaneously. In central Amazonia, we conducted a multiyear demographic census of 292 populations of two leaf‐inhabiting (i.e., epiphyllous) bryophyte species transplanted from continuous forest into a network of 10 study sites ranging from 1, 10, and 100 to >10,000 ha in size. All populations experienced significantly positive local growth ( \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape

The Bryum bicolor Complex in North America

\lambda > 1

A New Species of Vitalianthus (Lejeuneaceae, Hepaticae) from the Brazilian Amazon

\end{document} ) and a nearly constant per‐generational extinction probability (15%). However, experimental leaf patches in reserves of ≥100 ha experienced nearly double (48%) the colonization probability observed in small reserves (27%), suggesting that the proximate cause of epiphyll species loss in small fragments (≤10 ha) is reduced colonization. Nonetheless, populations of small fragments exhibit rates of colonization above patch extinction, positive local growth, and low temporal variation, which are features that should theoretically reduce the probability of extinction. This result suggests that for habitat‐tracking metapopulations subject to frequent and stochastic turnover events, including epiphylls, colonization/extinction ratios must be maintained well above unity to ensure metapopulation persistence.

Morphologische und anatomische Untersuchungen der Sporophyten bei den Jubulaceae Klinggr

Habitat fragmentation increases the migration distances among remnant populations, and is predicted to play a significant role in altering both demographic and genetic processes. Nevertheless, few studies have evaluated the genetic consequences of habitat fragmentation in light of information about population dynamics in the same set of organisms. In a 10 000‐km2 experimentally fragmented landscape of rainforest reserves in central Amazonia, we examine patterns of genetic variation (amplified fragment length polymorphisms, AFLPs) in the epiphyllous (e.g. leaf‐inhabiting) liverwort Radula flaccida Gott. Previous demographic work indicates that colonization rates in this species are significantly reduced in small forest reserves. We scored 113 polymorphic loci in 86 individuals representing five fragmented and five experimentally unmanipulated populations. Most of the variation (82%) in all populations was harboured at the smallest (400 m2) sampling unit. The mean (± SD) within‐population genetic diversity (Neis), of forest remnants (0.412 ± 0.2) was indistinguishable from continuous (0.413 ± 0.2) forests. Similarly, FST was identical among small (1‐ and 10‐ha) and large (≥ 100‐ha) reserves (0.19 and 0.18, respectively), but linkage disequilibrium between pairs of loci was significantly elevated in fragmented populations relative to those in continuous forests. These results illustrate that inferences regarding the long‐term viability of fragmented populations based on neutral marker data alone must be viewed with caution, and underscore the importance of jointly evaluating information on both genetic structure and demography. Second, multilocus analyses may be more sensitive to the effects of fragmentation in the short term, although the effects of increasing linkage disequilibrium on population viability remain uncertain.

Rhynchospora pseudomacrostachya, a new Brazilian species of Cyperaceae

Abstract The Bryum bicolor complex includes four species in North America: B. bicolor, B. gemmilucens, B. gemmiferum, and B. barnesii. Bulbil morphology is the most important taxonomic character for delineating the four North American species recognized, but care must be taken not to confuse them with morphologically similar restricted buds produced by other Bryum species. Bryum bicolor is the only northern hemisphere species of the complex with bulbils single per leaf axil, but is sometimes considered to be identical with the southern hemisphere species, B. dichotomum. After examination of the North American herbarium material and the types of B. bicolor and B. dichotomum, we could not perceive morphological differences between the two species. However, our survey did not include any other southern hemisphere specimens and we therefore kept the name B. bicolor pending for further studies on the variability of the species of the complex in the southern hemisphere. Bryum barnesii, B. gemmiferum, and B. gemmilucens all produce many bulbils per leaf axil but differ in bulbil color, shape. and size. Bryum gemmilucens is characterized by 100–200 μm long yellow, orange or red bulbils; B. barnesii by usually larger, 200–450 μm long greenish bulbils with broad, obtuse to largely acute primordia; and B. gemmiferum by 150–350 (450) μm long, yellow green, rarely brownish bulbils with tooth-like primordia. Leaf morphology is too variable to be used as a reliable taxonomic character within the complex. Costa length is quite variable, and plants exhibiting large bulbils and strongly excurrent costa approach B. dunense, considered to be a synonym of B. bicolor. Similarily, plants with broad leaves and laminal cells approach B. balticum, considered to be conspecific with B. barnesii. Bryum bicolor has been reported from 25 states of the United States and six Canadian provinces. Bryum barnesii, newly reported from North America, is most common along the Pacific coast, whereas both B. gemmiferum and B. gemmilucens are considered rare in North America.

First record of the chemical composition of essential oil of Piper bellidifolium, Piper durilignum, Piper acutilimbum and Piper consanguineum from the Brazilian Amazon forest

Abstract Infra-specific variation in phenotypes of bryophytes is rarely shown to be spatially or ecologically structured. By using a morphometrics approach based on more than 2,300 measurements of nine gametophyte characters taken from 63 specimens across the global range of Syrrhopodon leprieurii Mont. (Calymperaceae), we demonstrate through partial and total Mantel analyses that phenotypes vary significantly over distance and elevation. Furthermore, S. leprieurii specimens of montane and spatially isolated (island) regions (such as the Andes and Cuba) exhibit disproportionately greater morphological differentiation over relatively shorter distances when compared to those from lowland rainforests of the greater Amazon basin. Structured morphological variation among bryophyte populations is uncommon and we suggest that, in light of results from studies of other Neotropical plant taxa, more pronounced differentiation in niche structure in this region may account for such variability.

A tangled web in tropical tree‐tops: effects of edaphic variation, neighbourhood phorophyte composition and bark characteristics on epiphytes in a central Amazonian forest

Abstract A new species in the formerly monotypic genus Vitalianthus is described from Amazonas State, Brazil. Vitalianthus urubuensis sp. n. exhibits leaves with an unbroken chain of ocelli, upright orientation of the underleaf lobes, and a 4-keeled perianth lacking horn-like projections; all features that distinguish the only other known member of this genus, V. bischleriana (Porto & Grolle) R. M. Schust. & Giancotti. Differences between V. urubuensis and V. bischleriana are most evident in leaf and lobule morphology. The discovery of this new species in central Amazonia dramatically expands the geographic range of Vitalianthus, a taxon once considered endemic to the coastal rainforests of northeastern Brazil.