Mammal distributions in the western Mediterranean: the role of human intervention

The natural distribution of the 17 non-flying mammal species occurring wild in both the Maghreb (north-west Africa) and Iberia (south-west Europe) is considered. It is concluded that only four species – Red Fox Vulpes vulpes, Wild Boar Sus scrofa, Wild Cat Felis silvestris and Otter Lutra lutra – are native to both regions, while another three – Red Deer Cervus elaphus, Brown Bear Ursus arctos and Aurochs Bos primigenius – were native to North Africa until the mid-Holocene but have probably died out naturally. Algerian Hedgehog Atelerix algirus, Barbary Ape Macaca sylvanus, Genet Genetta genetta and Egyptian Mongoose Herpestes ichneumon are widely accepted as introductions to Europe from North Africa. The remaining six species, and Red Deer now found in Africa, were also probably introduced – Rabbit Oryctolagus cuniculus, Weasel Mustela nivalis, Wood Mouse Apodemus sylvaticus and Lesser White-toothed Shrew Crocidura russula from Europe to Africa; Algerian Mouse Mus spretus from Africa to Europe; Savi’s Pygmy Shrew Suncus etruscus perhaps from the eastern Mediterranean to both Iberia and the Maghreb. There are two Maghrebi species which, although not found in Europe, are more closely related to Palaearctic than to Afrotropical species: Garden Dormouse Eliomys melanurus, probably native to north-west Africa, although possible augmentation of the natural population cannot be ruled out, and Whitaker’s Shrew Crocidura whitakeri, a North African endemic. Removal of so many species of European provenance from the list of mammals native to north-west Africa should not be considered to weaken its position as part of the Palaearctic zoogeographical region. Bats and other, non-mammalian, taxa illustrate the clear faunal relationship between the Maghreb and south-west Europe, whilst emphasizing its distinction from subsaharan Africa.     

Transformation of mercuric chloride and methylmercury by the rumen microflora

The microflora in strained rumen fluid did not methylate or volatilize 203Hg2+ at detectable rates. However, there was an exponential decay in the concentration of added CH3Hg+, which was attributed to demethylation. The major product of demethylation was metallic mercury (Hg0), and it was released as a volatile product from the reaction mixture. Demethylation occurred under both anaerobic and aerobic conditions. The rate of demethylation was proportional to the concentration of added CH3Hg+-Hg from 0.02 to 100 microgram of Hg per ml. The presence of HgCl2 had almost no inhibitory effect on the rate of cleavage of the carbon-mercury bond of CH2HgCl, but it completely inhibited volatilization of the Hg formed, when the concentration of HgCl2-Hg reached 100 micrograms/ml. Three of 11 species of anaerobic rumen bacteria catalyzed demethylation. These were Desulfovibrio desulfuricans, Selenomonas ruminantium, and Megasphaera elsdenii. None of the 11 species caused detectable methylation, and only two caused limited volatilization of Hg2+. Three species of bacteria out of 90 fresh aerobic isolates from rumen contents were demethylators: two were identified as Pseudomonas sp., and the third was a Micrococcus sp. Demethylation by the rumen microflora appeared to be carried out by both aerobic and anaerobic bacteria and, on the basis of Hg2+ sensitivity, probably resulted from the activity of two enzymes, a CH3-Hg+ hydrolase and a Hg2+ reductase.     

Corticolous lichens as potential bioindicators of fire history: a study in the cerrado of the Distrito Federal, central Brazil

Abstract. The aim of this study was to investigate the potential use of epiphytic corticolous lichens as indicators of fire history in the cerrado (savannas) of central Brazil. Work was carried out at the Reserva Ecológica do IBGE and the Jardim Botânico de Brasilia, 33 km outside Brasilia D.F., in ten plots of cerrado denso within the ‘Fire Project’ area. Each plot was subjected to a specific prescribed burning regime, with study sites varying from a plot protected from fire for over 20 years to a plot burned every 2 years. Research was carried out in two stages: (1) a preliminary survey of plots with different fire histories, measuring variables about the lichen habitat and the lichen communities present in the habitats; (2) lichen sampling in plots with different fire histories, where collection and identification of lichen species took place. Field techniques used included plotless sampling, and identification of lichens was carried out using taxonomic keys, both in the field and in the laboratory. The results show that fire is a major determinant of epiphytic corticolous lichen communities in cerrado denso vegetation. The abundance, distribution and recolonization of lichen communities can clearly be correlated with the frequency and behaviour, in terms of homogeneity and flame heights, of the fires that have occurred in each of the plots surveyed. Particular lichen species also show differential sensitivities to fire frequency and behaviour. This study shows that responses of corticolous lichens, at both the community and species level, can be used as bioindicators of fire history in areas of cerrado denso vegetation in central Brazil.     

Transformation of mercuric chloride and methylmercury by the rumen microflora.

The microflora in strained rumen fluid did not methylate or volatilize 203Hg2+ at detectable rates. However, there was an exponential decay in the concentration of added CH3Hg+, which was attributed to demethylation. The major product of demethylation was metallic mercury (Hg0), and it was released as a volatile product from the reaction mixture. Demethylation occurred under both anaerobic and aerobic conditions. The rate of demethylation was proportional to the concentration of added CH3Hg+-Hg from 0.02 to 100 microgram of Hg per ml. The presence of HgCl2 had almost no inhibitory effect on the rate of cleavage of the carbon-mercury bond of CH2HgCl, but it completely inhibited volatilization of the Hg formed, when the concentration of HgCl2-Hg reached 100 micrograms/ml. Three of 11 species of anaerobic rumen bacteria catalyzed demethylation. These were Desulfovibrio desulfuricans, Selenomonas ruminantium, and Megasphaera elsdenii. None of the 11 species caused detectable methylation, and only two caused limited volatilization of Hg2+. Three species of bacteria out of 90 fresh aerobic isolates from rumen contents were demethylators: two were identified as Pseudomonas sp., and the third was a Micrococcus sp. Demethylation by the rumen microflora appeared to be carried out by both aerobic and anaerobic bacteria and, on the basis of Hg2+ sensitivity, probably resulted from the activity of two enzymes, a CH3-Hg+ hydrolase and a Hg2+ reductase.     

Separating the chance effect from other diversity effects in the functioning of plant communities

The effect of plant species diversity on productivity and competitive ability was studied in an experiment carried out simultaneously in five European countries: Czech Republic (CZ), the Netherlands (NL), Sweden (SE), Spain (SP), and United Kingdom (UK). The aim was to separate the ‘chance’ or ‘sampling effect’ (increasing the number of sown species increases the probability that a species able ‘to do a job’ will be included) from the complementarity effect (species‐rich communities are better able to exploit resources and to take care of ecosystem functions than species‐poor communities). In the experiment, low diversity (LD) and high diversity (HD) mixtures of grassland species were sown into fields taken out of arable cultivation. The HD mixture consisted of five grass species, five legumes and five other forbs. The LD mixtures consisted of two grasses, one legume and one other forb, with different plant species combinations in each replicate block. The design of the experiment was constructed in such a way that the total number of seeds of each species over all the replications was exactly the same in HD and LD treatments, and the total number of grass seeds, leguminous seeds and other forb seeds were the same in both LD and HD. The responses measured were the total above‐ground biomass (as a measure of productivity) and the average number of naturally establishing species in a plot (as a measure of the competitive ability of the mixture), both measured in the third year of the experiment.
The results show that, on average, the HD plots performed better (i.e., attained higher biomass, had better weed suppression), but that the best LD mixture was as good as the best HD mixture. On the contrary, the worst LD mixture was always less successful than the worst HD replicate. The performance of particular species in the HD mixtures was a good predictor of the success of a certain species combination in a LD mixture (explaining 61% of variability between particular LD mixtures). In all sites, the LD mixture composed of species which were the most abundant in HD mixtures was as efficient in suppressing weeds as the HD mixture itself. It is argued that the performance of a species assemblage is influenced mostly by the identity of species and the diversity effect is mainly due to the ‘chance’ or ‘sampling’ effect: with increasing number of species the probability that an important species will be included in the mixture increases. Caution is urged in interpreting experiments with manipulated diversity and the possible limitations of such experiments are discussed.     

Phylogenetic conservatism and trait correlates of spring phenological responses to climate change in northeast China

Climate change has resulted in major changes in plant phenology across the globe that includes leaf‐out date and flowering time. The ability of species to respond to climate change, in part, depends on their response to climate as a phenological cue in general. Species that are not phenologically responsive may suffer in the face of continued climate change. Comparative studies of phenology have found phylogeny to be a reliable predictor of mean leaf‐out date and flowering time at both the local and global scales. This is less true for flowering time response (i.e., the correlation between phenological timing and climate factors), while no study to date has explored whether the response of leaf‐out date to climate factors exhibits phylogenetic signal. We used a 52‐year observational phenological dataset for 52 woody species from the Forest Botanical Garden of Heilongjiang Province, China, to test phylogenetic signal in leaf‐out date and flowering time, as well as, the response of these two phenological traits to both temperature and winter precipitation. Leaf‐out date and flowering time were significantly responsive to temperature for most species, advancing, on average, 3.11 and 2.87 day/°C, respectively. Both leaf‐out and flowering, and their responses to temperature exhibited significant phylogenetic signals. The response of leaf‐out date to precipitation exhibited no phylogenetic signal, while flowering time response to precipitation did. Native species tended to have a weaker flowering response to temperature than non‐native species. Earlier leaf‐out species tended to have a greater response to winter precipitation. This study is the first to assess phylogenetic signal of leaf‐out response to climate change, which suggests, that climate change has the potential to shape the plant communities, not only through flowering sensitivity, but also through leaf‐out sensitivity.     

The embryonic and post-embryonic development in two Drosophila species exposed to the static magnetic field of 60 mT

In this study, a static magnetic field influence on development and viability in two different species, Drosophila melanogaster and Drosophila hydei, was investigated. Both species completed development (egg-adult), in and out of the static magnetic field induced by double horseshoe magnet. Treated vials with eggs were placed in the gap between magnetic poles (47 mm) and exposed to the average magnetic induction of 60 mT, while control ones were kept far enough from magnetic field source. We found that exposure to the static magnetic field reduced development time in both species, but statistical significance was found only for D. hydei. Furthermore, we found that the average viability of both Drosophila species exposed to the magnetic field was significantly weaker compared to control ones. These results indicate that 60 mT static magnetic field could be considered as a potential stressor, influencing on different levels the embryonic and post-embryonic development of individuals.     

The significance of carnivory for the fitness of Drosera in its natural habitat

Summary A field study of two carnivorous plant species, Drosera intermedia and D. rotundifolia, was carried out in a small silting-up bog in Southern Bavaria (FR Germany). Various parameters of undisturbed individuals of both species were measured for a period of two years and subjected to a partial correlation analysis. The importance of prey as a limiting factor for various fitness parameters was confirmed for both species. Other factors may occasionally also be limiting, e.g. assimilation area and water supply. Benefits obtained from the prey are partly transferred to the next year via the winter bud. The importance of the relative demonstrated: Plants of D. rotundifolia showed higher fitness values in higher positions, those of D. intermedia in lower positions. Growth characteristics of both species tended to influence the height of their own position in a corresponding direction: D. intermedia downwards and D. rotundifolia upwards. In both species negative effects of intraspecific neighbourhood were evident, whereas interspecific effects were not detectable. Plants of D. intermedia tend to influence their neighbourhood situation by changing their position by rhizome-like stem growth. In D. intermedia the decision to reproduce by seeds or axillary buds seems to be made at least partially already in the year before. D. rotundifolia was only observed reproducing by seeds. In spite of different catching characteristics (plant shape, plant size, microhabitats, prey spectra), the general catching success, measured as prey biomass per plant biomass, was equal in both species of sundew. This agrees with earlier findings that in this bog both species have the same biomass per ground area.     

Population Dynamics Constrain the Cooperative Evolution of Cross-Feeding

Cross-feeding is the exchange of nutrients among species of microbes. It has two potential evolutionary origins, one as an exchange of metabolic wastes or byproducts among species, the other as a form of cooperation known as reciprocal altruism. This paper explores the conditions favoring the origin of cooperative cross-feeding between two species. There is an extensive literature on the evolution of cooperation, and some of the requirements for the evolution of cooperative cross-feeding follow from this prior work–specifically the requirement that interactions be limited to small groups of individuals, such as colonies in a spatially structured environment. Evolution of cooperative cross-feeding by a species also requires that cross-feeding from the partner species already exists, so that the cooperating mutant will automatically be reciprocated for its actions. Beyond these considerations, some unintuitive dynamical constraints apply. In particular, the benefit of cooperative cross-feeding applies only in the range of intermediate cell densities. At low density, resource concentrations are too low to offset the cost of cooperation. At high density, resources shared by both species become limiting, and the two species become competitors. These considerations suggest that the evolution of cooperative cross-feeding in nature may be more challenging than for other types of cooperation. However, the principles identified here may enable the experimental evolution of cross-feeding, as born out by a recent study.     

Woody plants diversity,floristic composition and land use history in the Amazonian rain forests of Madidi National Park,Bolivia

A floristic inventory of woody plants was carried out to analyse the relationships between floristic similarity and geographical distance, and to compare the effect of land use history on the floristic composition between sites. Three lowland and two submontane sites were studied in Madidi, Bolivia. In one site, there is evidence of an Inca ruin. A total of 877 species and 12,822 individuals of woody plants with a diameter at breast height ≥2.5 cm were recorded in 44 0.1–ha plots. Fisher’s Alpha index values were slightly higher for the lowlands than for the submontane. Floristic similarity was higher within sites than between sites as measured by both Sørensen and Steinhaus indexes. The fact that the 30 most important species per site (totalling 94 species) accounted for 61.7% of total individuals, support the hypothesis that Amazonian plant communities are dominated by a limited set of species, genera and families. On the other hand, 18 out of the 94 species were reported in a single site, suggesting that some species are patchy in distribution and may be environmentally determined. Both the oligarchy and environmental-determinism hypotheses can be complementary in order to understand floristic patterns of this region. The Ruins submontane site is floristically the most distinct, and past human disturbance is likely to be the main reason. Since species diversity (ranging from 53 to 122 species per plot) and density (ranging from 157 to 503 per plot) are highly variable in Madidi, to characterize the diversity of a site, it is necessary to quantify an average of 10 0.1-ha plots in a relatively small geographical area.     

Optimal conservation strategy in fluctuating environments with species interactions: resource-enhancement of the native species versus extermination of the alien species

Alien species are often a major threat to native species. We consider optimal conservation strategies for a population whose viability is affected both by an alien species (such as a competitor, a predator, or a pathogen) and by random fluctuations of the environment (e.g. precipitation, temperature). We assume that the survivorship of the native population can be improved by providing resources such as food and shelter, and also by an extermination effort that decreases the abundance of the alien species. These efforts decrease the extinction probability of the native population, but they are accompanied by economic costs. We search for the optimal strategy that minimizes the weighted sum of the extinction probability and the economic costs over a single year. We derive conditions under which investment should be made in both resource-enhancement and extermination, and examine how the optimal effort levels change with parameters. When the optimal strategy includes both types of efforts, the optimal extermination effort level turns out to be independent of the density and economic value of the native species, or the variance of the environmental fluctuation. Furthermore, the optimal resource-enhancement effort is then independent of the density of the alien species. However, the parameter dependencies greatly change if one of the efforts becomes zero. We also examine the situation in which the impact of the alien species is uncertain. The optimal extermination effort increases with the uncertainty of this impact except when the cost of extermination is very high.     

Effect of time on the natural regeneration of salt marsh

Abstract. The effect of time on natural regeneration of two salt marshes was studied in relation to plant and edaphic factors. The study was carried out in two naturally restoring salt marshes, differing in restoration time, in Txingudi (Bay of Biscay). After 20 yr, the younger salt marsh had the same plant species richness and high species similarity as a 35 yr old salt marsh (17 and 16, respectively, similarity index = 0.9), but both sites had lower species richness and similarity than a nearby natural salt marsh (36 plant species and similarity indices of 0.45 with the 35 yr old marsh and 0.46 with the 20 yr old marsh). Plant species present in the two recovering salt marshes followed a similar distribution pattern in relation to organic matter, conductivity and moisture content although this zonation differed from the natural salt marsh. The range of edaphic factors measured was also similar, but differed from those in the natural salt marsh. The process of plant species recolonization and spatial distribution might be delayed by a low probability of species arrival and by the time need for the restoration of hydrologic and edaphic factors. This study supports the necessity of long‐term monitoring in measuring coastal salt marsh restoration.     

The evolution of non-maternal care in anthropoid primates: a test of the hypotheses

The amount of non-maternal care (allocare) found in primates varies greatly from species to species. Our paper examines this variation and focuses on possible reasons why mothers in some anthropoid primate species are prepared to relinquish their infants to other carers whereas others are not. We use data collected from the literature to test a number of hypotheses that attempt to explain the observed variation in non-maternal care. Analyses were carried out using comparative methods that control for the influence of both body size and phylogeny on life-history and ecological variation. The results support previous studies of both primates and other mammals in finding a clear link between the amount of allocare provided and female reproductive rates. Species with high allocare levels grow rapidly post-natally and wean their infants at a younger age (but at the same relative size) than species of the same body size with lower allocare levels. This early weaning allows high allocare species to support higher birth rates than low allocare species but does not result in earlier maturation. Our results, therefore, suggest that mothers allow non-maternal care of their infants in order to increase their own reproductive output. It is not clear whether such a strategy also benefits the infant, as we could find no link between the presence of allocare and early maturation (which would increase the infant's reproductive output) or between allocare levels and infant survival (as measured by vulnerability to infanticide). This suggests that mothers and infants might come into conflict over transfer to other carers, as the benefits to the mother may not be accompanied by benefits to the infant. However, although mothers may benefit from allocare in some circumstances, they will not be expected to allow allocare if the costs are high (e.g. if there is a high risk to the infant).     

A new species of the genus Paracryptops from India, with remarks on the generic and specific characters (Chilopoda: Scolopendromorpha: Cryptopidae)

Paracryptops spinosus , a new centipede species from Delhi, is described. The species is unique in the genus in that its anal legs have their femora and tibiae beset distally with extraordinary spines. It is pointed out that the exceedingly short poison claws supposed to be incapable of meeting in the middle cannot be depended upon to identify the genus Paracryptops . This character is apparent, not real and should be discarded. It is also pointed out that the number of tibial teeth used as a key character at species level, being subject to age variation, can be of limited taxonomic value and should be used with caution.     

Landscape and zonal distribution of bloodsucking mosquitoes and horseflies (Diptera: Culicidae,Tabanidae) in the northeastern Russian Plain

Analysis of landscape and zonal changes in the species diversity and abundance of 34 species of bloodsucking mosquitoes and 42 species of horseflies in the northeastern Russian Plain was carried out. The species diversity of both families is reduced from south to north. Two steps of faunistic depletion can be revealed: at the boundary of the middle and northern taiga (both mosquitoes and horseflies) and at the boundary of the extreme northern taiga and the forest-tundra (horseflies only). Species whose northern and southern distribution boundaries lie within the territory studied are listed.     

Comparative analysis of the excretory-secretory proteome of the muscle larva of Trichinella pseudospiralis and Trichinella spiralis

The nematodes Trichinella spiralis and Trichinella pseudospiralis are both intracellular parasites of skeletal muscle cells and induce profound alterations in the host cell resulting in a re-alignment of muscle-specific gene expression. While T. spiralis induces the production of a collagen capsule surrounding the host-parasite complex, T. pseudospiralis exists in a non-encapsulated form and is also characterised by suppression of the host inflammatory response in the muscle. These observed differences between the two species are thought to be due to variation in the proteins excreted or secreted (ES proteins) by the muscle larva. In this study, we use a global proteomics approach to compare the ES protein profiles from both species and to identify individual T. pseudospiralis proteins that complement earlier studies with T. spiralis. Following two-dimensional gel electrophoresis, tandem mass spectrometry was used to identify the peptide spots. In many cases identification was aided by the determination of partial peptide sequence from selected mass ions. The T. pseudospiralis spots identified included the major secreted glycoproteins and the secreted 5'-nucleotidase. Furthermore, two major groups of T. spiralis-specific proteins and several T. pseudospiralis-specific proteins were identified. Our results demonstrate the value of proteomics as a tool for the identification of ES proteins that are differentially expressed between Trichinella species and as an aid to identifying key parasite proteins that are involved in the host-parasite interaction. The value of this approach will be further enhanced by data arising out the current T. spiralis genome sequencing project.     

Factors influencing the seed source and sink functions of a floodplain nature reserve in the Netherlands

Question: How do species traits and abiotic factors influence the extent of hydrochorous dispersal into and out of a small floodplain area along a free‐flowing river in The Netherlands? Location: The Kappersbult nature reserve (53°07′28″N, 6°37′14″E), which is a floodplain along the Dutch River Drentsche Aa. Methods: Seeds transported by the river were collected in fine mesh nets for 24 consecutive hours once or twice a week for 1 year, upstream and downstream of the studied floodplain. Data on the captured seeds were related to species traits and abiotic factors and species composition in the floodplain. Results: The floodplain functioned both as a seed source and sink. High levels of river water seemed to promote seed transport to or from the floodplain. Seeds of riverbank species occurred significantly more often in the river water than expected. Net source species had significantly higher seed production, taller stature and higher seed buoyancy, but lower site elevation than net sink species. Seed weight was significantly higher for sink species than for other species. Conclusion: Our study found that inundation, and therefore more natural river water management, is a prerequisite for seed transport to and from a floodplain. The restoration of target floodplain vegetation may be successful for common species that produce many seeds and grow in proximity to the river. Consequently, it is expected that the probability of restoring vegetation types that occur further from the river, such as wet grasslands, by hydrochorous dispersal is low.     

Phylogeny and biogeography of the genus Pseudectinosoma, and description of P. janineae sp. n. (Crustacea, Copepoda, Ectinosomatidae)

Recent stygobiological investigations carried out in the circum-Mediterranean area resulted in the discovery of a new species of the genus Pseudectinosoma Kunz, described herein as P. janineae sp. n. The taxonomic status of the genus is reviewed in a phylogenetic perspective. The origin of the present-day distribution of the genus Pseudectinosoma is reconstructed both from patterns of relationships among the species and from palaeogeographical data.     

The biology and systematics of a new species of Xenopus (Anura: Pipidae) from the highlands of Central Africa

A new species of clawed toad, Xenopus wittei sp. nov. is described from highland areas overlapping the borders of Rwanda, Uganda and Zaire. A comprehensive morphological analysis of the species has been carried out. X. wittei sp. nov. is very closely related to X. vestitus and both have a tetraploid chromosome complement (2 n = 72), the only examples within the genus. Nevertheless, the two species may be distinguished by easily observed features, including head morphology and dorsal body colours and patterns, and are also identified by their karyotypes and mating calls.
Data on distribution, ecology and parasite infection are derived from both museum collections and fieldwork in Central Africa. X. wittei sp. nov. is sympatric in parts of its range with X. vestitus, X. laevis victorianus and X. I. bunyoniensis , with up to three of the taxa sharing the same habitats. The implications of potential species interactions are discussed. Experimental hybridization has confirmed the reproductive isolation of the two tetraploid species. Parasitological studies show that they may be distinguished from one another by host specific species of the nematode Chitwoodchabaudia and from other Xenopus species by the absence of the tapeworm genus Cephalochlamys . Large scale population movements of the Xenopus species have apparently occurred in the Central African highlands during the period of available records. Sympatry observed amongst the present day representatives of Xenopus may have been an important factor in the evolution of these toads since X. wittei sp. nov. and X. vestitus are interpreted as allopolyploids, the products of interspecies hybridization.