Multiple introductions are believed to play an important role in increasing genetic diversity and adaptability of invasive species, but there are few well-documented examples. The common reed, Phragmites australis, has dramatically increased in tidal wetlands throughout the USA in the past century due primarily to the introduction of a Eurasian lineage. In the Mississippi River "Balize" delta, P. australis is the dominant vegetation where monotypic stands of an introduced form blanket the outer marshes. The delta's interior marshes, on the other hand, are more vegetatively diverse, serving as important waterfowl foraging habitat. Recent encroachment by various phenotypic forms of P. australis into the interior marshes led to this study examining genetic variation in these stands. Our results revealed four chloroplast DNA haplotypes that also segregate based on microsatellite variation. Three of these are closely related and introduced, but differ relative to time and likely mode of introduction. The "Delta" type (haplotype M1), which is unique to the region and the most common lineage, displays considerable microsatellite diversity. The Eurasian introduced lineage of P. australis (haplotype M), which is invasive elsewhere in North America, is increasing its distribution in the delta. A novel haplotype, AD, was also identified which is phenotypically and genetically similar to haplotype M. Despite the close relatedness, we found no evidence for inter-haplotype gene exchange at the nuclear level, suggesting that intraspecific hybridization is not a contributing factor to these invasions. The site provides a unique opportunity for researchers to understand the dynamics of multiple P. australis invasions.
Patterns of plant species composition and their relationships to soil and topographic variables were investigated in tropical dry forests across the north central Yucatan, Mexico. Seven sites were studied in the oldest accessible forests along a 200-km transect oriented northwest to southeast; an eighth site was located in a little-disturbed area located 75 km northeast of the transect. Two of the sites were on Mayan ruins. All sites were sampled using 9 -24, 10 m ¥ 20 m plots (n = 132) for woody stems ≥ 3.0 cm diameter breast height. The important natural forest species were Bursera simaruba, Caesalpinia gaumeri, Gymnopodium floribundum, Piscidia piscipula, and Thouinia paucidentata. The two most important woody species in ruin woodlands were Brosimum alicastrum and Croton lundellii. Forest plots (n =108) had 17 species on average, ruin plots (n = 24) nine species. Mean basal area of stems at the forest plots (20.7 m 2 .ha -1 ) was lower than in ruin plots (28.4 m 2 .ha -1 ). Detrended Correspondence Analysis generally placed plots by site along the geographic transect. Natural forest plots and sites were separated from the plots on ruin sites. The five soil and topographic variables (slope, soil depth, percent surface rock, soil pH, total soil organic matter) differed significantly among sites. Plot values were correlated with DCA axe scores. Intersite floristic variation reflects an overall west to east environmental gradient affected by climate.
A new classification of the higher taxonomic levels within the New World bat family Phyllostomidae is presented which designates evolutionary relationships, provides a phylogenetic framework upon which modifications can be made as new comparative data are produced, and resolves certain obvious unnatural taxa that exist in the traditional classification. This new classification is a synthesis of classical morphological, chromosomal, and biochemical data. Within the family three subfamilies, the Desmodontinae, Phyllostominae, and Vampyrinae are recognized. The Desmodontinae includes the three genera of vampires, the Vampyrinae includes Vampyrum, Trachops, and Chrotopterus, and the Phyllostominae contains three tribes, the Phyllostomini (including Phyllostomus, Tonatia, Mimon, Lonchorhina, and Macrophyllum), the Glossophagini (including genera of the previously recognized Glossophaginae and Brachyphyllinae), and Stenodermatini (including genera of the previously recognized Stenodermatinae and Carolliinae). Two genera (Macrotus and Micronycteris), do not share synapomorphies with any of these subfamilies, but have retained a large number of plesiomorphic features and are placed as incertae sedis. [Classification; phylogenetic reconstruction; Phyllostomidae.]
Type species Noctilio albiventer [=albiventris] Spix. CONTEXT AND CONTENT. Order Chiroptera, Suborder Microchiroptera, Superfamily Phyllostomoidea, Family Noctilionidae. The genus Noctilio contains only two species; they may be distinguished on the basis of characters discussed in the account that follows.
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