An eleven-year cycle in human births

The prominent endogenous cycle of the sun, with a period of approximately 11 years, is correlated with human conceptions. Time series methods (periodograms and periodic regression analyses) established that an approximate 11-year period exists in the data on births in the 20th century (1909–1985) in the United States and in New Zealand. Statistical comparisons indicated a reliable and direct relationship of conceptions with the approximately 11-year sunspot cycle. These findings were discussed in terms of the possible mediating role of geomagnetic disturbances and other factors that have been suggested in the literature to mediate human conception.     

Disturbances by dog barking increase vigilance in coots Fulica atra

Animals frequently interrupt their activity to look up and to scan their surrounding environment for potential predators (vigilance). As vigilance and other activities are often mutually exclusive, such behaviours are at the expense of feeding, sleeping or preening. Authors of many wildlife disturbance studies found that people with free-running dogs provoked the most pronounced disturbances (e.g. greater flushing distances and more birds affected). However, dogs on leash may also negatively affect wild animals, and barking dogs may lead to an increase in vigilance. In this study, I tested this hypothesis in coots (Fulica atra) using three different playback procedures: (1) dog barks, (2) conspecific coot alarm calls and (3) chaffinch song. The trials were conducted in spring and autumn 2005 at three study sites in southwestern Germany. During the dog playbacks, vigilance increased significantly from 17 to 28%. This increase in vigilance is comparable to the presence of a natural predator. As expected, vigilance also increased significantly during conspecific coot alarm calls but not during playbacks of the chaffinch song control. Two main findings result from the study: (1) coots respond to acoustic traits of dogs and may be able to acoustically recognise this predator and (2) this increase in vigilance might have implications for conservation, especially when considering buffer zones around sensitive areas.     

Historical records and increasing trends of Caribbean Flamingos (Phoenicopterus ruber) on Margarita Island,Venezuela

ABSTRACT

The Caribbean Flamingo (Phoenicopterus ruber) has been a species of conservation concern since the 1960s because of its regional population decline and loss of breeding colonies. In the last two decades, there have been reports of increasing population trends in the Caribbean. The aim of this work is to document the historic population status of flamingos on Margarita Island, Venezuela, and to present an account of their recovery since 2006. In the first half of the twentieth century, flamingos were present on Margarita Island in one location (La Restinga lagoon) in variable numbers (100–800); however, in the 1980s and 1990s, they almost disappeared from the island. In 2006, a group of nine was recorded. During the following years, the population increased in number and expanded eastward on the island. Today, the population size range 1 600–2 000 individuals, are present regularly in at least eight lagoons, and two breeding colonies have been reported. Several threats are still present in the island that can revert the positive population trend. The recovery of the population in Margarita Island is a consequence of successful regional conservation efforts and the maintenance of wetlands with appropriate conditions for the species, particularly in protected areas.     

Aescin and troxerutin as a successful combination for the treatment of inner ear perfusion disturbances

A fixed combination of aescin and troxerutin has been developed for treating inner ear perfusion problems of different aetiology. The efficacy of this combination is tested versus pentoxyfyllin in a randomized clinical study as group comparison with 34 patients for each group. The improvement of hearing after 40–44 days of treatment is determined as end point of treatment. Hearing was measured by threshold, whereby a difference of more than 10 dB is judged as a significant improvement. After the treatment with the combination of aescin and troxerutin hearing is significantly improved, in 23 of 34 patients the threshold is changed more than 10 dB, which is checked by sign-test with p<0.05. With pentoxyfyllin hearing is also improved, although to a lesser degree. Both drugs are well tolerated, major adverse drug effects are not observed with either treatment.     

Climate change impacts on structure and diversity of fish communities in rivers

It is widely accepted that climate change constrains biota. Yet, because of the lack of consistent multisite and multitaxon surveys, few studies have addressed general rules about how climate change impacts on structure and diversity of animal communities. Especially, the relative influence of nonclimatic anthropogenic disturbances on this impact is fairly unknown. Here, we present for the first time a meta-analysis assessing the effect of global warming on stream organisms. Fish communities of large rivers in France undergoing various anthropogenic pressures showed significant increase in proportions of warm-water species and of specific richness during the last 15–25 years. Conversely, the equitability decreased, indicating a gradual decrease of the number of dominant species. Finally, the total abundance increased, coupled with rejuvenation and changes in size-structure of the communities. Interestingly, most of these effects were not depressed by the strength of nonclimatic anthropogenic disturbances. Conversely, geographical location of communities and especially closeness of natural barriers to migration could influence their response to climate change. Indeed, increase in the proportion of southern species seemed hindered at sites located close to the southern limit of the European species' geographical ranges. This work provides new evidence that climate change have deep impacts on communities which, by overtaking the effects of nonclimatic anthropogenic disturbances, could be more substantial than previously thought. Overall, our results stress the importance of considering climate change impacts in studies addressing community dynamics, even in disturbed sites.     

The Role of Small-Scale Turbulence in the Distribution of Macrofouling Organisms on the Hulls of Ocean-Going Ships

Evidences in favor of the hypothesis of Rudyakova [23] are given, which states that the main reason for the aggregative distribution of fouling organisms on the hulls of active long-voyage crafts (ocean-going ships) is the uneven course of hydrodynamical process around the submerged part of the hull, particularly the development of small-scale turbulence at sites of separation of the boundary layer (shear sites).     

Impacts of volcanic eruptions and early recovery in freshwater environments and organisms

Volcanic eruptions modify environments physically and chemically with serious consequences for the biota. In this review, we analysed 80 papers reporting the effects of volcanic eruptions in freshwater environments and on freshwater organisms. An increase in water turbidity is the most common reported physical effect while increases in concentrations of inorganic elements, many representing nutrients for primary producers, are the most common chemical effects. Bacterial growth is usually stimulated, while autotrophs can be either positively or negatively affected depending on the type of impact. A persistent effect reported in the biota is changes to the assemblage, which could generate further changes in terms of ecosystem functions. This analysis also identifies some information gaps, particularly involving the effects of eruptions on heterotrophic biofilms in streams and on invertebrates and fish in lakes. Most studies were carried out soon after the volcanic eruption, so it is difficult to assess the recovery of the ecosystems. Eruptions present unique opportunities for scientific discovery, although such studies are often hindered by a lack of pre-eruption data, which would allow for a more comprehensive assessment of the effects.     

Aridity and chronic anthropogenic disturbance as organizing forces of fruit-feeding butterfly assemblages in a Caatinga dry forest

Anthropogenic disturbances and climate change are expected to reorganize biodiversity on multiple ecological levels from populations to ecosystems, especially in arid and semiarid regions due to environmental filtering imposed by water stress. This paper examines the individual and combined effects of chronic anthropogenic disturbance and increased aridity on the structure of fruit-feeding butterfly assemblages in a human-modified landscape of Caatinga dry forest, in the northeast of Brazil. Butterflies were recorded monthly across old-growth forest stands and their assemblages were described in terms of taxonomic and functional community-level attributes confronted to different levels of chronic disturbance and aridity. Butterfly assemblages were species-poor but had high species replacement (turnover) along both the chronic disturbance and aridity gradients. We observed a negative effect of aridity on alpha and beta diversity of butterfly assemblages. Butterfly assemblages across forest stands exposed to high levels of chronic disturbance and aridity had a nested structure. Functional diversity (Rao's Q) and the community-weighted means (CWM) of ocellus-bearing species and monocot-feeding larvae were negatively and positively affected by increased aridity and chronic disturbance, respectively. Our findings suggest that aridity and its combination with chronic disturbance have a drastic effect on the structure of butterfly assemblages in the Caatinga dry forest. These findings highlight that rainfall and chronic disturbances as major drivers of biological reorganization in human-modified landscapes. As aridity increases, Caatinga tends to support taxonomically and functionally impoverished and highly distorted assemblages. Abstract in Portuguese is available with online material     

Promoting survival prospects of rare plants

Many hypotheses have been put forward to explain the structure and position of alpine treelines. The spatial complexity of the ecotone, ranging from sharp boundaries to networks of tree patches within a heath matrix, may explain why no consensus has been reached. In this paper, we discuss factors from abiotic disturbances to herbivory that may help understand the spatial structure of the alpine treeline ecotone in Fennoscandia. The ecotone is dominated by mountain birch (Betula pubescens ssp. tortuosa), and may show a wide range of spatial structures. We discuss the influence of topography, seed limitations, seedling establishment, growth limitations, abiotic disturbances and herbivory as structuring factors. All of these factors may operate, but their relative importance in space and time is unknown. There is a basic difference between factors that prevent the establishment of trees, and thus act on early life history stages, and factors that thin out a previously dense forest, and thus act on adult trees. Mortality caused directly or indirectly by geometrid moths may belong to the latter category. We suggest that seedling and sapling mortality is more important than seed limitation for the establishment of new individuals in the treeline ecotone. Important mortality factors may be abiotic disturbances, competition (or allelopathy) from field layer plants and herbivory. The relative role of these factors needs to be examined further.     

Habitat utilisation and nesting behaviour of two sympatric weavers in Mbalmayo District,Cameroon

Avian ecology and behaviour data provides crucial information for bird conservation and management, but are still missing for many species, particularly in developing countries. This study examines habitat utilisation, nesting behaviour, anthropogenic disturbances and impacts on agricultural crops of Village Weaver Ploceus cucullatus and Vieillot’s Black Weaver Ploceus nigerrimus in Mbalmayo District, Cameroon. Abundance was estimated by nest counts and point counts of birds at 40 previously located colonies, where also tree metrics and anthropogenic disturbances were measured. In total, more than 1 700 birds of the two species were estimated within a 9 km2 study area, divided into two blocks and five different habitat types. Village Weavers were generally more abundant, especially in the urban habitat, whereas Vieillot’s Black Weavers were most numerous in the rural habitat. Among the tree species used for nesting, mango Mangifera indica and African border tree Newbouldia laevis had the highest nest counts, which also was positively related to canopy cover diameter. Traffic noise disturbance was associated with lower bird and nest counts, whereas the opposite was observed on farming disturbance. The relative impacts on agricultural crops were estimated for African oil palm Elaeis guineensis (38%), maize Zea mays (36%), Musa spp. (18%) and Mangifera indica (8%). The implications for long-term coexistence between farmland birds and humans are discussed, and the challenge is to minimise both kinds of bird–human interactions, i.e. anthropogenic disturbances and agricultural crop damage.