Long-Term Changes of a Coastal Bird Breeding Community on a Small Island – Does Natural Succession Compromise Conservation Values?

Limited spatial resources available for conservation lead to controversy about whether to apply single-species management or ecosystemary approaches in order to maintain biodiversity. In this study I analyse changes in a community of breeding coastal birds over a 90-year period, in order to examine whether natural processes on an unmanaged island are in accordance with requirements to save endangered species. Both diversity and species richness of the community increased significantly over time, and evenness increased after having been severely reduced by human impact. Diversity, evenness and species richness seemed to approach an equilibrium in the past decade, but number of breeding pairs declined as a consequence of altered natural disturbance regime. Species identity changed over time, with two initially very common species recently becoming locally extinct. These species are of high conservation concern, and their disappearance causes a problem for the concept of naturalness on islands. I conclude that natural processes need to be applied to the entire landscape in order to maintain dynamic processes that are essential for the survival of these species. The natural changes on the island should not be interrupted, but rather demonstrated to the public in order to increase conservation mindedness and gain support for changes in anthropogenic influences on a larger spatial scale.     

Size as a line of least evolutionary resistance: diet and adaptive morphological radiation in New World monkeys

New World monkeys (NWM) display substantial variation (two orders of magnitude) in body size. Despite this, variation in skull size and associated shape show a conserved allometric relationship, both within and between genera. Maximum likelihood estimates of quantitative ancestral states were used to compare the direction of morphological differentiation with the phenotypic (p(max)) and genetic (g(max)) lines of least evolutionary resistance (LLER). Diversification in NWM skulls occurred principally along the LLER defined by size variation. We also obtained measures of morphological amount and pace of change using our skull data together with published genetic distances to test whether the LLER influenced the amount and pace of diversification. Moreover, data on an ecological factor (diet) was obtained from the literature and used to test the association of this niche-related measure with the morphological diversification. Two strategies were used to test the association of LLER with the morphological and dietary amount and pace of change, one focusing on both contemporary genera and maximum likelihood reconstructed ancestors and the other using only the 16 contemporary genera in a phylogenetic comparative analysis. Our results suggest that the LLER influenced the path, amount, and pace of morphological change. Evolution also occurred away from the LLER in some taxa but this occurred at a slower pace and resulted in a relatively low amount of morphological change. We found that longer branch lengths (time) are associated with larger differences in p(max) orientation. However, on a macroevolutionary scale there is no such trend. Diet is consistently associated with both absolute size differences and morphological integration patterns, and we suggest that this ecological factor might be driving adaptive radiation in NWM. Invasion of diet-based adaptive zones involves changes in absolute size, due to metabolic and foraging constraints, resulting in simple allometric skull diversification along the LLER. While it is clear that evolutionary change occurred along the LLER, it is not clear whether this macroevolutionary pattern results from a conservation of within-population genetic covariance patterns or long-term adaptation along a size dimension or whether both constraints and selection were inextricably involved.     

Biotic resistance to an invasive spider conferred by generalist insectivorous birds on Hawai’i Island

A central problem for ecology is to understand why some biological invasions succeed while others fail. Species interactions frequently are cited anecdotally for establishment failure, but biotic resistance is not well supported by quantitative experimental studies in animal communities. In a 33-month experiment on Hawaii Island, exclusion of native and alien forest birds resulted in a 25- to 80-fold increase in the density of a single non-indigenous spider species (Theridiidae: Achaearanea cf. riparia). Caged plots held large aggregations of juveniles and more large-bodied individuals, suggesting potential reproductive individuals are more susceptible to bird predation. Most examples of biotic resistance involve competition for limiting resources among sessile marine animals or terrestrial plants. The present results show that generalist predators can limit the success of introductions, even on oceanic islands, generally assumed less resistant to invasion.     

Cajal-type cells from human mammary gland stroma: phenotype characteristics in cell culture

We report here the in vitro isolation of Cajal-like interstitial cells from human inactive mammary-gland stroma. Primary cell cultures examined in phase-contrast microscopy or after vital methylene-blue staining revealed a cell population with characteristic morphological phenotype: fusiform, triangular or polygonal cell body and the corresponding (very) long, slender, moniliform cytoplasmic processes. Giemsa staining pointed out the typical knobbed aspect of cell prolongations. Immunofluorescence (IF) showed, like in situ immunohistochemistry, that Cajal-type cells in vitro (primary cultures), expressed c-kit/CD117 and vimentin. In conclusion, the images presented here reinforce our previous hypothesis that human mammary glands have a distinct population of Cajal-like cells in non-epithelial tissue compartments.     

Interstitial Cajal-like cells (ICLC) in human resting mammary gland stroma. Transmission electron microscope (TEM) identification

We have previously shown the existence of ICLC in human resting mammary gland stroma by means of methylene blue (vital) staining and c-kit immunopositivity (immunofluorescence and immunohistochemistry). In addition, we reported the phenotype characteristics of these ICLC in vitro (primary cell cultures). Since the identification of ICLC outside the gut requires, at this moment, the obligatory use of TEM, we used this technique and provide unequivocal evidence for the presence of ICLC in the intralobular stroma of human resting mammary gland. According to the 'platinum standard' (10 TEM criteria for the certitude diagnosis of ICLC), we found interstitial cells with the following characteristics: 1. location: among the tubulo-alveolar structures, in the non-epithelial space; 2. caveolae: approximately 2.5% of cell volume; 3. mitochondria: approximately 10% of cell volume; 4. endoplasmic reticulum: either smooth or rough, approximately 2-3% of cell volume; 5. cytoskeleton: intermediate and thin filaments, as well as microtubules are present; 6. myosin thick filaments: undetectable; 7. basal lamina: occasionally found; 8. gap junctions: occasionally found; 9. close contacts with targets: nerve fibers, capillaries, immunoreactive cells by 'stromal synapses'; 10. characteristic cytoplasmic processes: i) number: frequently 2-3; ii) length: several tens of mum; iii) thickness: uneven caliber, 0.1-0.5 microm, with dilations, but very thin from the emerging point; iv) aspect: moniliform, usually with mitochondria located in dilations; v) branching: dichotomous pattern; vi) Ca(2+) release units: are present; vii) network labyrinthic system: overlapping cytoplasmic processes. It remains to be established which of the possible roles that we previously suggested for ICLC (e.g. juxta- and/or paracrine secretion, uncommited progenitor cells, immunological surveillance, intercellular signaling, etc.) are essential for the epithelium/stroma equilibrium in the mammary gland under normal or pathological conditions.     

Anaerobic Processes as the Core Technology for Sustainable Domestic Wastewater Treatment: Consolidated Applications, New Trends, Perspectives, and Challenges

Anaerobic digesters have been responsible for the removal of large fraction of organic matter (mineralization of waste sludge) in conventional aerobic sewage treatment plants since the early years of domestic sewage treatment (DST). Attention on the anaerobic technology for improving the sustainability of sewage treatment has been paid mainly after the energy crisis in the 1970s. The successful use of anaerobic reactors (especially up-flow anaerobic sludge blanket (UASB) reactors) for the treatment of raw domestic sewage in tropical and sub-tropical regions (where ambient temperatures are not restrictive for anaerobic digestion) opened the opportunity to substitute the aerobic processes for the anaerobic technology in removal of the influent organic matter. Despite the success, effluents from anaerobic reactors treating domestic sewage require post-treatment in order to achieve the emission standards prevailing in most countries. Initially, the composition of this effluent rich in reduced compounds has required the adoption of post-treatment (mainly aerobic) systems able to remove the undesirable constituents. Currently, however, a wealth of information obtained on biological and physical-chemical processes related to the recovery or removal of nitrogen, phosphorus and sulfur compounds creates the opportunity for new treatment systems. The design of DST plant with the anaerobic reactor as core unit coupled to the pre- and post-treatment systems in order to promote the recovery of resources and the polishing of effluent quality can improve the sustainability of treatment systems. This paper presents a broader view on the possible applications of anaerobic treatment systems not only for organic matter removal but also for resources recovery aiming at the improvement of the sustainability of DST.     

The fate of sheep-dispersed seeds: Plant species emergence and spatial patterns

Sheep epizoochory has often been proposed as an important vector which can help to overcome the dispersal limitation of plants in fragmented landscapes. In order to evaluate the contribution of herbivores to recruitment especially of target species, the dispersal and post-dispersal fate of such seeds must be known. In a field experiment sheep with seeds of mainly target species (experimentally attached to their coats) were present at three sand plots for 24 h. Natural epizoochorous dispersal was already shown for most of the species in our study area. Seed detachment, trampling intensity and seed shadow were measured; seedling emergence and survival were recorded over an 8-month period. In addition, the effect of sheep trampling on seedling emergence and survival of two threatened species, Jurinea cyanoides and Koeleria glauca, were studied.     

The role of contextual conditioning in the effect of reinforcer devaluation on instrumental performance by rats

Different groups of rats received different amounts of training to lever press for a food reinforcer before an aversion was conditioned to the food. This devaluation of the reinforcer reduced responding in both subsequent extinction and reinforced tests of responding to a degree that was independent of the amount of instrumental training. Moreover, interpolating context extinction between aversion conditioning and the extinction test reduced the magnitude of the devaluation effect, thereby indicating that Pavlovian contextual conditioning may play a role in the instrumental devaluation effect.     

Independence and interdependence in the nest-site choice by honeybee swarms: Agent-based models, analytical approaches and pattern formation

In a recent paper List, Elsholtz and Seeley (List et al., 2009) have devised an agent-based model of the nest-choice dynamics in swarms of honeybees, and have concluded that both interdependence and independence are needed for the bees to reach a consensus on the best nest site. We here present a simplified version of the model which can be treated analytically with the tools of statistical physics and which largely has the same features as the original dynamics. Based on our analytical approaches it is possible to characterize the co-ordination outcome exactly on the deterministic level, and to a good approximation if stochastic effects are taken into account, reducing the need for computer simulations on the agent-based level. In the second part of the paper we present a spatial extension, and show that transient non-trivial patterns emerge, before consensus is reached. Approaches in terms of Langevin equations for continuous field variables are discussed.     

Antimicrobial activity of steady-state cultures of Bacillus sp. CCMI 1051 against wood contaminant fungi

The effect of changing dilution rate (D) on Bacillus sp. CCMI 1051 at dilution rates between 0.1 and 0.55 h⁻¹ in a glucose-limited medium was studied. Biomass values varied between 0.88 and 1.1 g L⁻¹ at D values of 0.15–0.35 h⁻¹. Maximal biomass productivity was found to be 0.39 g L⁻¹ h⁻¹, obtained at D = 0.35 h⁻¹ and corresponding to a 54.4% conversion of the carbon into cell mass. The highest rate of glucose consumption was 4.45 mmol g⁻¹ h⁻¹ occurring at D = 0.4 h⁻¹. The glucose concentration inside the chemostat was below the detection level starting to accumulate around 0.4 h⁻¹. Growth inhibition of fifteen strains of fungi by the broth of the steady-state cell-free supernatants was assessed. Results showed that the relative inhibition differ among the target species but was not influenced by the dilution rate changing.