Frugivores at higher risk of extinction are the key elements of a mutualistic network

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Efeito da fragmentação sobre a persistência de anfíbios anuros (Amphibia: Anura) na Mata Atlântica

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Macroecology of Caribbean Bats: Effects of Area, Elevation, Latitude, and Hurricane-Induced Disturbance

Understanding the geographic and environmental characteristics of islands that affect aspects of biodiversity is a major theme in ecology (Begon et al. 2006; Krebs 2001) and biogeography (Cox and Moore 2000; Drakare et al. 2006; Lomolino et al. 2006). Such understanding has become particularly relevant over the past century because human activities on continents have fragmented natural landscapes, often creating islands of isolated habitat dispersed within a sea of land uses that include agriculture, forestry, and various degrees of urban and suburban development. The increasingly fragmented or islandlike structure of mainland habitats has critical ramifications to conservation biology, as it provides insights regarding the mechanisms leading to species persistence and loss. Consequently, the study of patterns and mechanisms associated with island biodiversity is of interest in its own right (Whittaker 1998; Williamson 1981), and may provide critical insights into mainland phenomena that otherwise could not be studied because of ethical, financial, or logistical considerations involved with the execution of large-scale manipulative experiments.

Efeito da fragmentação sobre a persistência de anfíbios anuros (Amphibia: Anura) na Mata Atlântica

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

How deforestation pattern in the Amazon influences vertebrate richness and community composition

The effects of habitat configuration on species persistence are predicted to be most apparent when remaining habitat cover is below 30%. We tested this prediction by comparing vertebrate communities in 21 landscapes located in the southern Amazonia, including 7 control landscapes (similar to 100% of forest cover) and 14 fragmented landscapes (4 x 4 km). The fragmented landscapes retained similar proportions of forest (similar to 25%), but had contrasting configurations, resulting from two different deforestation patterns: the "fish-bone pattern" common in small properties, and the large-property pattern generally used by large ranchers. Vertebrates were surveyed in all landscapes in February-July 2009 with interviews (n = 150). We found a significant difference in reported species richness among the fish-bone, large-property, and control areas (mean = 29.3, 38.8 and 43.5 respectively). Control areas and large-properties tended to have a higher number of specialist species (mean = 13.7, and 11.7, respectively), when compared with the fish-bone pattern (5.1). Vertebrate community composition in the control and large-properties was more similar to one another than to those of the fish-bone landscapes. The number of fragments was the main factor affecting the persistence of species, being negatively associated with specialist species richness. Species richness was also positively related with the size of the largest fragment structurally connected to the studied landscapes (i.e., a regional scale effect). Our results demonstrated that the large-property pattern, which results in less fragmented landscapes, can maintain a more diverse community of large vertebrates, including top predators, which are considered fundamental for maintaining ecosystem integrity. These results support the hypothesis that landscape configuration contributes to the persistence and/or extirpation of species.

Evolution of South African Bruniaceae: evidence from ecological and geographical investigations

The central aim of the present study was to analyse ecological and geographical mechanisms that led to the species diversity and distribution pattern of the South African (sub-) endemic Bruniaceae shown today. To answer the question if the endangerment of some species and the sometimes restricted distribution area is due to an incongruence of pollination and breeding system, pollinator observations and the breeding system were analysed. rnThe effectiveness of the plant-pollinator interactions should be reflected in the reproductive success wherefore fruit set analyses were carried out. The genetic constitution of distant and close-by populations along a spatial gradient should illuminate gene-flow or habitat isolation that could have led to the species diversity. Since niche-inhabitation could be shown in the present study, an overall biogeographical analysis illuminated the distribution pattern on family level and the geographical as well as ecological factors that led to species persistence. rnThe study illuminated that the plant-pollinator interactions and the breeding system are adaptations to the fynbos biome but can not be defined as factors that drove speciation or have tremendous influence on distribution of Bruniaceae. In fact the geography of South Africa with its fragmented landscape as well as close niche-inhabitation of co-occuring species is the reason for species diversity and the recent distribution.rn

Speciation in Freshwater Fishes

The extraordinary species richness of freshwater fishes has attracted much research on mechanisms and modes of speciation. We here review research on speciation in freshwater fishes in light of speciation theory, and place this in a context of broad-scale diversity patterns in freshwater fishes. We discuss several major repeated themes in freshwater fish speciation and the speciation mechanisms they are frequently associated with. These include transitions between marine and freshwater habitats, transitions between discrete freshwater habitats, and ecological transitions within habitats, as well as speciation without distinct niche shifts. Major research directions in the years to come include understanding the transition from extrinsic environment-dependent to intrinsic reproductive isolation and its influences on species persistence and understanding the extrinsic and intrinsic constraints to speciation and how these relate to broad-scale diversification patterns through time.

Persistence times of four amphipod species in the stomachs of brown trout

Four amphipod species fed to brown trout Salina trutta persisted in an easily identifiable form in trout stomachs for similar lengths of time. The data also allowed estimation of the maximum length of time ingested amphipods could persist in an identifiable form in brown trout stomachs at different temperatures. The data are thus useful in assessment of fish feeding patterns on amphipod assemblages in the laboratory and field. (C) 2001 The Fisheries Society of the British Isles.

Survival and persistence of opportunistic Burkholderia species in host cells

Burkholderia are microorganisms that have a unique ability to adapt and survive in many different environments. They can also serve as biopesticides and be used for the biodegradation of organic compounds. Usually harmless while living in the soil, these bacteria are opportunistic pathogens of plants and immunocompromised patients, and occasionally infect healthy individuals. Some of the species in this genus can also be utilised as biological weapons. They all possess very large genomes and have two or more circular chromosomes. Their survival and persistence, not only in the environment but also in host cells, offers a remarkable example of bacterial adaptation.

Species Diversity is a Good Predictor of Prairie Plant Persistence in Restorations

Prairie restoration projects sometimes fail because of heavy invasion by invasive weeds, especially if they are not intensively managed. Few restoration projects are sampled after the first few years post-establishment, and little is known about what predictors are significant in maintaining restored communities over the very long term. Here, we stopped weeding experimental restoration plots to determine if persistence (that is, remaining unchanged after weeds are allowed to invade) of native prairie in western Iowa was related to planted species diversity

A new method for conservation planning for the persistence of multiple species

Although the aim of conservation planning is the persistence of biodiversity, current methods trade-off ecological realism at a species level in favour of including multiple species and landscape features. For conservation planning to be relevant, the impact of landscape configuration on population processes and the viability of species needs to be considered. We present a novel method for selecting reserve systems that maximize persistence across multiple species, subject to a conservation budget. We use a spatially explicit metapopulation model to estimate extinction risk, a function of the ecology of the species and the amount, quality and configuration of habitat. We compare our new method with more traditional, area-based reserve selection methods, using a ten-species case study, and find that the expected loss of species is reduced 20-fold. Unlike previous methods, we avoid designating arbitrary weightings between reserve size and configuration; rather, our method is based on population processes and is grounded in ecological theory.

Using complex network metrics to predict the persistence of metapopulations with asymmetric connectivity patterns

Almost all metapopulation modelling assumes that connectivity between patches is only a function of distance, and is therefore symmetric. However, connectivity will not depend only on the distance between the patches, as some paths are easy to traverse, while others are difficult. When colonising organisms interact with the heterogeneous landscape between patches, connectivity patterns will invariably be asymmetric. There have been few attempts to theoretically assess the effects of asymmetric connectivity patterns on the dynamics of metapopulations. In this paper, we use the framework of complex networks to investigate whether metapopulation dynamics can be determined by directly analysing the asymmetric connectivity patterns that link the patches. Our analyses focus on “patch occupancy” metapopulation models, which only consider whether a patch is occupied or not. We propose three easily calculated network metrics: the “asymmetry” and “average path strength” of the connectivity pattern, and the “centrality” of each patch. Together, these metrics can be used to predict the length of time a metapopulation is expected to persist, and the relative contribution of each patch to a metapopulation’s viability. Our results clearly demonstrate the negative effect that asymmetry has on metapopulation persistence. Complex network analyses represent a useful new tool for understanding the dynamics of species existing in fragmented landscapes, particularly those existing in large metapopulations.

Hormone-dependent bacterial growth persistence and biofilm formation - A pilot study investigating human follicular fluid collected during IVF cycles

Human follicular fluid, considered sterile, is aspirated as part of an in vitro fertilization (IVF) cycle. However, it is easily contaminated by the trans-vaginal collection route and little information exists in its potential to support the growth of microorganisms. The objectives of this study were to determine whether human follicular fluid can support bacterial growth over time, whether the steroid hormones estradiol and progesterone (present at high levels within follicular fluid) contribute to the in vitro growth of bacterial species, and whether species isolated from follicular fluid form biofilms. We found that bacteria in follicular fluid could persist for at least 28 weeks in vitro and that the steroid hormones stimulated the growth of some bacterial species, specifically Lactobacillus spp., Bifidobacterium spp. Streptococcus spp. and E. coli. Several species, Lactobacillus spp., Propionibacterium spp., and Streptococcus spp., formed biofilms when incubated in native follicular fluids in vitro (18/24, 75%). We conclude that bacteria aspirated along with follicular fluid during IVF cycles demonstrate a persistent pattern of growth. This discovery is important since it can offer a new avenue for investigation in infertile couples.

Characterization of in vitro Chlamydia muridarum persistence and utilization in an in vivo mouse model of Chlamydia vaccine

Problem: Chlamydia trachomatis genital tract infections are easily treated with antibiotics, however the majority of infections are asymptomatic and therefore untreated, highlighting the need for a vaccine. Because most infections are asymptomatic, vaccination could potentially be administered to individuals who may have an acute infection at that time. In such individuals the effect of vaccination on the existing infection is unknown; however one potential outcome could be the development of a persistent infection. In vitro chlamydial persistence has been well characterized in various strains, however there have been no reported studies in C. muridarum. Method of Study: We performed ultrastructural characterization, and transcriptome analysis of selected genes. We then used the transcriptional profiles of the selected genes to examine whether intranasal immunization of mice during an active genital infection would induce persistence in the upper reproductive tract of female mice. Results and Conclusions: We found that persistence developed in the oviducts of mice as a result of immunization. This is a significant finding, not only because it is the first time that C. muridarum persistence has been characterized in vitro, but also due to the fact that there is minimal characterization of in vivo persistence of any chlamydial species. This highlights the importance of the timing of vaccination in individuals.