Effects of urban development and habitat alterations on the distribution and abundance of native and exotic freshwater fish in the Brisbane region,Queensland

The distribution of freshwater fish in creeks throughout the Brisbane region was determined by a survey carried out in 1977–78. Seventeen native and six exotic species were recorded in 55 creeks. Sixteen native and four exotic species were collected in a more restricted survey of central Brisbane in 1981. Urban development and the establishment of exotic plants have resulted in substantial changes to the aquatic environment in many of the creeks surveyed. Exotic grasses, especially para grass (Brachiaria mutica) have reduced the extent of free water by growing partly into stream channels. Floating exotic plants blanketed some stream reaches. Native aquatic macrophytes have declined, apparently due to dredging, siltation and other disturbances. These changes have affected the distribution and abundance of native and exotic fish. Native species with a preference for open water and beds of aquatic plants have declined in creeks overgrown by para grass and floating plants. Melanotaenia fluviatilis, Retropinna semoni, Pseudomugil signifer, Craterocephalus stercusmuscarum and Ambassis nigripinnis have been affected. Para grass and floating plants have not affected the range or abundance of Hypseleotris galii, H. compressus and Mogurnda adspersa. Gambusia affinis and Xiphophorus helleri have been advantaged by expansion of their preferred habitat type - the edges of pools where exotic grasses have grown partly into the water. The effect of exotic fish on native species is unclear. There was a correlation between large numbers of G. affinis and small numbers of H. galii and M. fluviatilis. Correlations could result from predatory or competitive interactions between species. Alternatively, correlations could be due entirely to the effects of habitat alterations on exotic and native species. However, H. galii was evidently not disadvantaged by the habitat alterations studied. Thus there may be a complex interaction between this species and G. affinis. There was no evidence that X. helleri had affected the range or abundance of native species.     

Disturbance and demography of Phylica arborea (Rhamnaceae) on the Tristan-Gough group of islands

Populations of Phylica arborea Thouars, an evergreen tree endemic to six southern oceanic islands, have been depleted by wood gathering and browsing on Amsterdam Island and Tristan da Cunha, and it was feared that introduced rodents were destroying seed and reducing regeneration on uninhabited Gough Island. A comparison of the demography of this species on four islands in the Tristan-Gough group suggests that rodents have little effect on seedling numberS. Regeneration seldom occurs in undisturbed P. Arborea groves: germination and seedling survival appears to be dependent on periodical removal of established trees and understorey vegetation by soil-slips and occasional fireS. Climatic and vegetation differences problably account for the less frequent regeneration at Gough Island relative to that at the Tristan islands.     

Distribution Patterns of Tropical Plant Foods as an Evolutionary Stimulus to Primate Mental Development

Primates are noted for their mental abilities but the selective basis for such traits has remained obscure. It is hypothesized that the element of predictability associated with the spatial and temporal distribution patterns of plant foods in tropical forests has served to stimulate mental development in primates taking much of their food from the first trophic level. Primates able to remember the locations and phenological patterns of a wide variety of plant foods could move directly to such foods when and where available without wasting time and energy in random search. This would enhance overall foraging success by lowering procurement costs associated with a varied and patchily distributed plant diet. Membership in a cohesive social unit, that utilized the same supplying area over many consecutive generations, would also enhance foraging success by serving to transmit important information about diet to close kin. Data on the foraging behavior of howler and spider monkeys are presented to test certain implications of this hypothesis. Similar selective pressures, but applied to foods from the second trophic level, may have been of critical importance in the mental development of hominids . [primates, evolution, intelligence, plant foods, Aleles, Alouatta ]     

Whole-genome duplications in South American desert rodents (Octodontidae)

The discovery of tetraploidy in the red viscacha rat, Tympanoctomys barrerae (4 n  = 102) has emphasized the evolutionary role of genome duplication in mammals. The tetraploid status of this species is corroborated here by in situ PCR and Southern blot analysis of a single-copy gene. The species meiotic configuration strongly suggests a hybrid derivation. To investigate the origin of T. barrerae further, the recently described Pipanacoctomys aureus was studied. This 92-chromosome species also has a duplicated genome size, redundant gene copy number and diploid-like meiotic pairing, consistent with an event of allotetraploidization. Phylogenetic analysis of mitochondrial sequences indicates sister-group relationships between these two tetraploid rodents. The new karyotypic data and the phylogenetic relationships suggest the participation of the ancestral lineages of Octomys mimax in the genesis of P. aureus . The high overall DNA similarity and shared band homology revealed by genomic Southern hybridization as well as matching chromosome numbers between O. mimax and the descendant tetraploid species support the notion of introgressive hybridization between these taxa.  © 2004 The Linnean Society of London, Biological Journal of the Linnean Society , 2004, 82 , 443–451.     

HIV risk behaviors among outpatients with severe mental illness in Rio de Janeiro,Brazil

We conducted the first study to examine rates of sexual activity, sexual risk behaviors, sexual protective behaviors, injection drug use (IDU), needle sharing, and knowledge about HIV/AIDS among outpatients with severe mental illness (SMI) in Rio de Janeiro, Brazil. Using a measure with demonstrated reliability, we found that 42% of 98 patients engaged in vaginal or anal sex within the past three months. Comorbid substance use disorder was significantly associated with sexual activity. Only 22% of sexually active patients used condoms consistently, despite having better HIV knowledge than those who were sexually abstinent. Overall, 45% of patients reported not engaging in any HIV protective behaviors. There were no reports of drug injection. Adults with SMI in Brazil are in need of efficacious HIV prevention programs and policies that can sustain these programs within mental health treatment settings.