Changes and availability of P fractions following 65 years of P application to a calcareous soil in a Mediterranean climate

The fate and availability of P derived from granular fertilisers in an alkaline Calcarosol soil were examined in a 65-year field trial in a semi-arid environment (annual rainfall 325 mm). Sequential P fractionation was conducted in the soils collected from the trial plots receiving 0–12 kg P ha⁻¹crop⁻¹, and the rhizosphere soil after growing wheat (Triticum aestivum L. cv. Yitpi) and chickpea (Cicer arietinum L. cv. Genesis 836) for one or two 60-day cycles in the glasshouse. Increasing long-term P application rate over 65 years significantly increased all inorganic P (Pi) fractions except HCl–Pi. By contrast, P application did not affect or tended to decrease organic P (Po) fractions. Increasing P application also increased Olsen-P and resin-P but decreased the P buffer capacity and sorption maxima. Residual P, Pi and Po fractions accounted for an average of 32, 16 and 52% of total P, respectively. All soil P fractions including residual P in the rhizosphere soil declined following 60-day growth of either wheat or chickpea. The decreases were greater in soils with a history of high P application than low P. An exception was water-extractable Po, which increased following plant growth. Changes in various P fractions in the rhizosphere followed the same pattern for both plant species. Biomass production and P uptake of the plants grown in the glasshouse correlated positively with the residual P and inorganic fractions (except HCl–Pi) but negatively with Po in the H₂O-, NaOH- and H₂SO₄-fractions of the original soils. The results suggest that the long-term application of fertiliser P to the calcareous sandy soil built up residual P and non-labile Pi fractions, but these P fractions are potentially available to crops.     

The contribution of island populations to in situ genetic conservation

Genetic variation is often lower within island populations, however islands may also harbor divergent genetic variation. The likelihood that insular populations are genetically diverse or divergent should be influenced by island size and isolation. We tested this assumption by comparing patterns of genetic variation across all major island song sparrow populations along the Pacific North American coast. Allelic richness was moderately lowered even on islands which are close to large, potential sources. The most significant differences in allelic richness occurred on very small or highly remote islands. Gene diversity was significantly lower only on remote or very small islands. We found that island populations contribute to regional genetic variation through both the amount of genetic variation and the uniqueness of that variation. The partitioning of this contribution was associated with the size and isolation of the island populations.     

Is vascular plant species diversity a predictor of bryophyte species diversity in Mediterranean forests?

This study aimed to (i) investigate the congruence among the species composition and diversity of bryophytes and vascular plants in forests; (ii) test if site prioritization for conservation aims by the maximization of the pooled number of vascular plant species is effective to maximize the pooled number of bryophyte species. The study was performed in six forests in Tuscany, Italy. Four-hundred and twenty vascular plant species (61 of which were woody) and 128 bryophyte species were recorded in 109 plots. Despite the good predictive value of the compositional patterns of both woody plants and total vascular with respect to the compositional pattern of bryophytes, the species richness of the latter was only marginally related to the species richness of the former two. Bryophyte rare species were not spatially related to rare plant species and neither coincided with the sites of highest plant species richness. The species accumulation curves of bryophytes behaved differently with respect to those of woody plants or total vascular plants. Reserve selection analysis based on the maximization of the pooled species richness of either woody plants or total vascular plants were not effective in maximizing the pooled species richness of bryophytes. This study indicates that species diversity of vascular plants is not likely to be a good indicator of the bryophyte species diversity in Mediterranean forests.     

The mitochondrial 16 s rRNA reveals high anthropogenic influence on land snail diversity in a preliminary island survey

A total of 30 specimens belonging to five species, namely; Cryptozona siamensis, Sarika resplendens and Sarika sp. from the family Ariophantidae as well as Quantula striata and Quantula sp. from the family Dyakiidae were collected from the Langkawi Island in Northern Peninsular Malaysia. All specimens were identified through comparisons of shell morphology and amplification of a 500 bp segment of the 16S rRNA mtDNA gene. To assess phylogenetic insights, the sequences were aligned using ClustalW and phylogenetic trees were constructed. The analyses showed two major lineages in both Maximum Parsimony and Neighbour Joining phylogenetic trees. Each putative taxonomic group formed a monophyletic cluster. Our study revealed low species and intraspecies genetic diversities based on the 16S rRNA gene sequences. Thus, this study has provided an insight of land snail diversity in populations of an island highly influenced by anthropogenic activities through complementary use of shell morphological and molecular data.     

No benefit in diversity? The effect of genetic variation on survival and disease resistance in a polygynous social insect

1. Multiple mating by queens has been shown to enhance disease resistance in insect societies, because higher genetic diversity among nestmates improves collective immune defences or offers a certain level of herd immunity. However, it has remained ambiguous whether polygynous societies with large numbers of queens also benefit from increased genetic diversity. 2. We used one of the very few ant species that can be reared across generations, the pharaoh ant, Monomorium pharaonis Linnaeus, to create experimental colonies with two types of enhanced genetic diversity: (i) mixed workers from three divergent inbred lineages representing the ‘polygyny‐equivalent' of multiple mating by queens (i.e. increased between‐worker variation); and (ii) uniform workers whose overall heterozygosity was increased by two subsequent generations of crossing between the same divergent inbred lineages (i.e. increased within‐worker variation). 3. We found significant differences in worker survival among the three inbred lineages, with exposure to conidiospores of the fungal pathogen Beauveria bassiana causing significant mortality to the workers independently of their diversity type. Increased diversity did not improve the resistance to Beauveria. 4. Enhanced heterozygosity colonies had worker survival rates similar to the most resistant inbred lineage, whereas colonies with mixed workers from the three inbred lineages had lower worker and larval survival. Workers did not show any infection‐avoidance behaviour. 5. Average larval survival appeared unaffected by the presence of conidiospores. It benefitted from increased heterozygosity but was reduced in mixed colonies independent of infection. This suggests that negative, but cryptic social interactions in mixed colonies may affect overall survival. 6. The present results do not provide evidence for or against a link between increased genetic variation and increased disease resistance in pharaoh ants, but show that colonies differ considerably in general survival. Thus, increasing the genetic diversity of pharaoh ant colonies may not provide survival advantages in the face of pathogen exposure, and polygyny and polyandry may not be directly comparable mechanisms for creating adaptive resistance towards pathogens.     

Invasive rats and seabirds after 2,000 years of an unwanted coexistence on Mediterranean islands

In the Mediterranean, the survival of endemic long-lived seabirds despite the long-standing introduction of one of the most damaging alien predator, the ship rat (Rattus rattus), on most islands constitutes an amazing conservation paradox. A database gathering information on approximately 300 Western Mediterranean islands was analyzed through generalized linear models to identify the factors likely to influence ship rat presence and to account for how ship rat presence and island characteristics may have driven the presence and abundance of seabirds. Our review showed that few Mediterranean islands remain rat-free. At the regional scale, rat presence was only a limiting factor in the abundance of the smallest seabird, the storm petrel (Hydrobates pelagicus), while the distribution and abundance of the three shearwaters were more influenced by island characteristics. We hypothesized that the long-term persistence of these seabirds may have been facilitated by the various biogeographical contexts of Mediterranean islands, likely to provide intra-island refuges.     

The influence of landscape structure on ants and dung beetles diversity in a Mediterranean savanna—Forest ecosystem

Ants and dung beetles are focal indicators of change in several ecological processes and successional vegetation stages in Mediterranean landscapes. Despite relatively good knowledge of local species distributions, there are few data on their distributions at different scales. In the present study, the influence of multiscale landscape structure was examined using both ants and dung beetles to identify species that can serve as indicators and detectors of changes in vegetation structure. Multiscale analysis is necessary to explore the different roles of indicator and detector species for use as tools in studies focused on monitoring ecological changes. The study area was the Cabañeros National Park, in the center of the Iberian Peninsula. This site was selected because it is a good setting to evaluate the effects of typical vegetation mosaics on Mediterranean species at different scales. In this study, dung beetles and ants were trapped for one year. A multiscale analysis was designed using three different vegetation habitats (forest, scrubland and grassland) and landscape matrices (woodland, scrubland and grassland). Among dung beetles, 23 indicator species (IndVal values higher than 70%) were found at different scales of analysis. In addition, 20 dung beetle species were characterized as detector species (IndVal values between 45 and 70%) for the three different levels analyzed. Similar to the dung beetles, the ants had different species assemblages at various habitats and landscape levels; however, no indicator ant species were found in this study. All species with significant IndVal values (n = 8) were identified as detector species. Thus, ant and dung beetle assemblages were influenced in different ways by vegetation structure. Both groups showed strong individual species responses to different Mediterranean landscape conditions and vegetation types. Further, both insect groups showed a great number of detector species, which can be useful in ecosystem management because they have varying degrees of preference and sensitivity for different ecological states (such as successional vegetation stages). The diverse indicator and detector species identified in this work could be useful tools for the detection of landscape structure changes at both levels habitat patches and landscape matrix. However, a generalisation of the results at landscape scale should be taken with precaution, but they encourage to study more regions and similar landscapes. The use of more than one indicator group in the analysis confirms the importance of selecting groups with different sensitivities at varying spatial scales as well as different ecosystem functions. This strategy allows the establishment of a clear baseline with which to analyze future direct and indirect impacts of management in Mediterranean protected areas.     

Genetic structure of the feral cat (Felis catus L.) introduced 50 years ago to a sub-Antarctic island

Information about the invasion dynamics and demographic status of invasive species is essential to choose the optimal control options of population numbers. While long-term direct demographic and historical records are generally lacking, the analysis of the genetic variability of a current population might supply information about past and current demographic processes. In this study, we analysed the genetic variability of the cat population living on the main island of the Kerguelen archipelago. Genetic diversity was consistent with the introduction of a very small number of individuals followed by a demographic explosion of the cat population. Significant genetic structure among sites (F_st=0.06 ±0.005) and absence of isolation by distance could indicate that the initial phase of fast colonisation is now over. Estimates of individual relatedness indicated a significant kin structure. Overall data suggested that the cat population of the main island has probably reached carrying capacity.     

Plant response to disturbance in a Mediterranean grassland: How many functional groups?

Abstract. Data referring to changes in vegetation composition resulting from cattle exclosure and ploughing in a Portuguese pasture dominated by annuals were used to test hypotheses regarding the biology of species favoured or eliminated by disturbance in semi-natural herbaceous communities. These hypotheses were tested in two ways. First we compared the distribution of six a priori groups – grasses, small rosettes, large rosettes, small species with leafy stems, large species with leafy stems, legumes – across grazed, ploughed and undisturbed plots. In a second set of analyses we examined changes in the frequencies of individual biological attributes in response to grazing and ploughing. These analyses were carried out separately for grasses and dicot forbs. Overall, the species composition showed little response to either grazing or ploughing, though species dominance changed. This lack of responsiveness of species composition was attributed to the long history of intensive land use which has resulted in the loss of disturbance-intolerant species over entire landscapes. When considering a priori groups, small rosettes were indifferent to disturbance. grazing and ploughing showed that dominated. Large rosettes, large species with leafy stems and legumes were generally intolerant to both grazing and ploughing, though individual species may increase in response to disturbance. Small species with leafy stems were the only group favoured by grazing whereas ploughing favoured grasses. As to individual traits, grazing excluded large grass species with heavy seeds and promoted a flat rosette canopy structure and a small size, along with a moderate dormancy and protected inflorescences. In forbs, grazing favoured small species, as expected, while it excluded tall species, and, in contrast to earlier results, a rosette canopy. These attributes were consistent with responses of the a priori groups, though it would not have been possible to reconstruct groups directly from the attribute list. Ploughing had no effect on any of the forb traits. As to grass traits, flat- and short-statured species increased and heavy-seeded species decreased. Our analysis revealed two advantages of establishing plant functional classifications within life forms. Subgroups within forbs had contrasting types of behaviour. For the same trait patterns could differ within the grass group from within the forb group. Finally, this analysis emphasizes the need for plant functional classifications aiming at the identification of syndromes of co-occurring attributes rather than of lists of isolated traits of which actual combinations are not specified.     

Understory response to varying fire frequencies after 20 years of prescribed burning in an upland oak forest

Ecosystems in the eastern United States that were shaped by fire over thousands of years of anthropogenic burning recently have been subjected to fire suppression resulting in significant changes in vegetation composition and structure and encroachment by invasive species. Renewed interest in use of fire to manage such ecosystems will require knowledge of effects of fire regime on vegetation. We studied the effects of one aspect of the fire regime, fire frequency, on biomass, cover and diversity of understory vegetation in upland oak forests prescribe-burned for 20 years at different frequencies ranging from zero to five fires per decade. Overstory canopy closure ranged from 88 to 96% and was not affected by fire frequency indicating high tolerance of large trees for even the most frequent burning. Understory species richness and cover was dominated by woody reproduction followed in descending order by forbs, C3 graminoids, C4 grasses, and legumes. Woody plant understory cover did not change with fire frequency and increased 30% from one to three years after a burn. Both forbs and C3 graminoids showed a linear increase in species richness and cover as fire frequency increased. In contrast, C4 grasses and legumes did not show a response to fire frequency. The reduction of litter by fire may have encouraged regeneration of herbaceous plants and helped explain the positive response of forbs and C3 graminoids to increasing fire frequency. Our results showed that herbaceous biomass, cover, and diversity can be managed with long-term prescribed fire under the closed canopy of upland oak forests.     

How does variation in total and relative abundance contribute to gradients of species diversity?

Patterns of biodiversity provide insights into the processes that shape biological communities around the world. Variation in species diversity along biogeographical or ecological gradients, such as latitude or precipitation, can be attributed to variation in different components of biodiversity: changes in the total abundance (i.e., more‐individual effects) and changes in the regional species abundance distribution (SAD). Rarefaction curves can provide a tool to partition these sources of variation on diversity, but first must be converted to a common unit of measurement. Here, we partition species diversity gradients into components of the SAD and abundance using the effective number of species (ENS) transformation of the individual‐based rarefaction curve. Because the ENS curve is unconstrained by sample size, it can act as a standardized unit of measurement when comparing effect sizes among different components of biodiversity change. We illustrate the utility of the approach using two data sets spanning latitudinal diversity gradients in trees and marine reef fish and find contrasting results. Whereas the diversity gradient of fish was mostly associated with variation in abundance (86%), the tree diversity gradient was mostly associated with variation in the SAD (59%). These results suggest that local fish diversity may be limited by energy through the more‐individuals effect, while species pool effects are the larger determinant of tree diversity. We suggest that the framework of the ENS‐curve has the potential to quantify the underlying factors influencing most aspects of diversity change.     

Does interspecific competition with a stronger competitor explain the rarity of an endangered snake on a Mediterranean island?

Interspecific competition has been demonstrated to be an important shaping force for snake communities worldwide, but relatively few studies have investigated its occurrence and extent with island assemblages of snakes. In Sardinia (Mediterranean Sea), two species of whip snakes (Colubridae) co-occur, one of them being abundant and widespread (Hierophis viridiflavus) and the other being localized and critically endangered (Hemorrhois hippocrepis). A previous hypothesis suggested that the latter species would be confined to suboptimal habitats by the former species, which is a stronger competitor for food. As a consequence, He. hippocrepis would not only be rare but would also be smaller in body size in Sardinia than in other regions of its range where Hi. viridiflavus does not occur. In 1999?C2010, we studied habitat selection, food habits, and body sizes of these two snakes in sympatric populations, applying a suite of statistical tools including null models and Monte Carlo simulations. We observed that dietary habits were different between species (compared to Hi. viridiflavus, He. hippocrepis more frequently preyed upon rodents and less frequently on lizards, and within rodent prey, more frequently upon Rattus and less frequently upon Mus), but not in a way compatible with competitively induced trophic niche partitioning. The two species were similar in terms of prey size and predator-size?Cprey-size relationships. They also differed in habitat selection (maquis was the preferred habitat for both, but Hi. viridiflavus was found significantly more often than He. hippocrepis in grasslands, cultivations, and artificial pinewoods) but again in a non-competitively directed way. In addition, there was no evidence for the hypothesis that He. hippocrepis was confined to suboptimal habitats. Body sizes were similar between species (with males being significantly larger than females), and Sardinian He. hippocrepis were not smaller than conspecifics inhabiting regions without Hi. viridiflavus. Overall, our study showed that the two species differed in some aspects of their ecology, but these differences could not be due to competitive interactions. The conservation implications of these results are also discussed.     

Contrasted levels of genetic diversity in a benthic Mediterranean octocoral: Consequences of different demographic histories?

Understanding the factors explaining the observed patterns of genetic diversity is an important question in evolutionary biology. We provide the first data on the genetic structure of a Mediterranean octocoral, the yellow gorgonian Eunicella cavolini, along with insights into the demographic history of this species. We sampled populations in four areas of the Mediterranean Sea: continental France, Algeria, Turkey, and the Balearic and Corsica islands. Along French coasts, three sites were sampled at two depths (20 and 40 m). We demonstrated a high genetic structure in this species (overall F_ST = 0.13), and most pairwise differentiation tests were significant. We did not detect any difference between depths at the same site. Clustering analyses revealed four differentiated groups corresponding to the main geographical areas. The levels of allelic richness and heterozygosity were significantly different between regions, with highest diversity in Algeria and lowest levels in Turkey. The highest levels of private allelic richness were observed in Algeria followed by Turkey. Such contrasted patterns of genetic diversity were not observed in other Mediterranean octocorals and could be the result of different evolutionary histories. We also provide new empirical evidence of contrasting results between tests and model‐based studies of demographic history. Our results have important consequences for the management of this species.     

Conservation genetic assessment of four plant species in a small replica of a steppe ecosystem >30 years after establishment

To counter species loss living ex situ collections in botanic gardens became important elements of robust conservation programs. Several limitations, problems, and risks associated with living ex situ collections have been reported such as appropriate cultivation management to maintain genetic diversity and stochastic effects in small isolated populations in artificial habitats. However, not all small and isolated populations exhibit these predicted genetic changes. In a multi-species in situ/ex situ comparison of sand dune steppe- and grassland vegetation >30 years after the ex situ population establishment, we compared four different species’ population genetic diversities (Alyssum montanum ssp. gmelinii, Gypsophila fastigiata, Helianthemum nummularium ssp. obscurum, Onosma arenaria) by means of ISSR. We observed different species-specific genetic responses to quite similar abiotic selective forces concerning different neutral genetic diversities of wild versus botanic garden populations. The genetic divergence was kept relatively low in two of the four investigated species between the model steppe plant community within the botanic garden where human interference was kept at a minimum and the wild population. However, the moderate genetic divergence of the two other species kept under the same conditions highlights the importance of species-specific intrinsic responses and stochastic effects to ecosystem changes and provides data on population genetic dynamics in small and isolated populations. This contributes to further improve recommendations on how to best conserve endangered plant species in ex situ environments (cultivation in near nature-like replicas of the original site with as little human inference as possible over only certain periods of time, >30 years).     

Mineralisation of carbon and plant uptake of phosphorus from microbially-derived organic matter in response to 19 years simulated nitrogen deposition

Here we test the hypotheses that 19 years of simulated pollutant N deposition increases both losses of carbon (C) and the ability of plants to access P from organic material in upland heathland. The grass, Dactylis glomerata, and the dwarf shrub, Calluna vulgaris, were grown in soil containing microbial-derived organic matter labelled with ¹⁴C and ³³P. We found that both soil and root-surface phosphatase activity increased significantly in response to N deposition. We also found a significant positive relationship between root-surface phosphatase activity and ³³P uptake for Calluna, but a negative relationship for Dactylis. Efflux of ¹⁴C from the microbial-derived organic matter was strongly dependent on an interaction among plant presence, plant species and N deposition. Our results show that mineralisation of C and P, and subsequent plant uptake of P from organic sources is decoupled. In our experimental conditions, stimulation of P turnover coupled with subsequent plant uptake through up-regulation of root phosphatases is little affected by N addition. However, our data indicate that root-surface phosphatases are likely to be more important for uptake of P derived from organic sources for Calluna than for Dactylis.     

Is there a benefit of excluding sheep from pastures at flowering peak on flower-visiting insect diversity?

Permanent grasslands are an important habitat for insect communities, including pollinator populations which are in pan-European decline. Here, we investigated the benefits of temporarily excluding sheep from pastures on butterfly (Lepidoptera: Rhopalocera and Zygaenidae) and bumblebee (Hymenoptera: Bombidae) communities in two semi-natural grasslands differing in soil fertility and surrounding landscapes. We compared the impact of continuous grazing against rotational grazing (RG) at the same stocking rate but in which a subplot was excluded from the rotation during the main flowering period. We predicted that the diversity of flower-visiting insect community would be improved by RG due to the preservation of flower-rich patches and the maintenance of sward heterogeneity. Benefits of RG management were mainly evidenced on bumblebee density and species richness, with some additional effects on local density of butterflies during the subplot-exclusion period. Temporarily excluding sheep from pastures during peak flowering could thus offer an opportunity to preserve the diversity of flower-visiting insects, in spite of weaker benefits than could have been expected from previous surveys with cattle.     

Reversal of a reflex to a single motoneuron in the stick insect Çarausius morosus

In inactive stick insects ramp-wise stretching of the femoral chordotonal organ excites the slow extensor tibiae motoneuron. In active animals the same stimulus decreases the firing rate of this motoneuron. The time-course of increased and decreased activity of this motoneuron can be seen with triangular stimulation.Supported by the Deutsche Forschungsgemeinschaft     

A mosaic of opportunities? Spatio-temporal patterns of bat diversity and activity in a strongly humanized Mediterranean wetland

The Baixo Vouga Lagunar (BVL) landscape, in the Portuguese central-west coast, harbours a mosaic of wetland habitat types, interspersed by intensive and extensive agricultural fields, pastures, production forests and urban areas. In this study, we aimed to determine the species composition and the structure of the bat assemblages of the different habitats that constitute this heterogeneous landscape and to investigate seasonal changes in the patterns of bat diversity and activity across habitats. We acoustically sampled bats across 24 sampling sites representative of the eight main habitat types that shape the landscape—Bocage, forests, maize fields, marshlands, reed beds, rice fields, sea rushes and urban settlements. We compared bat richness, diversity and evenness across habitat types and seasons. We analysed habitat-specific and season-specific overall bat activity, and because habitat selection by bats is known to reflect morphological characters, foraging strategies and echolocation call structures, we also analysed the activity of individual species and of eco-morphological guilds. From 1,544 bat-passes recorded, we identified 12 species. Pipistrellus pygmaeus, Pipistrellus pipistrellus and Eptesicus serotinus/Eptesicus isabellinus were the most frequently recorded. Species composition and activity were similar across habitats, whilst exhibiting strong seasonal dynamics within habitats. Our results suggest that the mosaicism of the landscape provides several opportunities for bats, enabling them to explore different resources in distinct habitat patches. However, it may also reflect a forced exploitation of less optimal habitats and resources by bats, due to the scarcity of opportunities provided by fragmented landscapes.     

Three years of insecticide resistance monitoring in Anopheles gambiae in Burkina Faso: resistance on the rise?

ABSTRACT: Background and methods A longitudinal Anopheles gambiae s.l. insecticide-resistance monitoring programme was established in four sentinel sites in Burkina Faso. For three years, between 2008 and 2010, WHO diagnostic dose assays were used to measure the prevalence of resistance to all the major classes of insecticides at the beginning and end of the malaria transmission season. Species identification and genotyping for target site mutations was also performed and the sporozoite rate in adults determined. RESULTS: At the onset of the study, resistance to DDT and pyrethroids was already prevalent in An. gambiae s.l. from the south-west of the country but mosquitoes from the two sites in central Burkina Faso were largely susceptible. Within three years, DDT and permethrin resistance was established in all four sites. Carbamate and organophosphate resistance remains relatively rare and largely confined to the south-western areas although a small number of bendiocarb survivors were found in all sites by the final round of monitoring. The ace-1R target site resistance allele was present in all localities and its frequency exceeded 20% in 2010 in two of the sites. The frequency of the 1014 F kdr mutation increased throughout the three years and by 2010, the frequency of 1014 F in all sites combined was 0.02 in Anopheles arabiensis, 0.56 in An. gambiae M form and 0.96 in An. gambiae S form. This frequency did not differ significantly between the sites. The 1014 S kdr allele was only found in An. arabiensis but its frequency increased significantly throughout the study (P = 0.0003) and in 2010 the 1014 S allele frequency was 0.08 in An. arabiensis. Maximum sporozoite rates (12%) were observed in Soumousso in 2009 and the difference between sites is significant for each year. CONCLUSION: Pyrethroid and DDT resistance is now established in An. gambiae s.l. throughout Burkina Faso. Results from diagnostic dose assays are highly variable within and between rounds of testing, and hence it is important that resistance monitoring is carried out on more than one occasion before decisions on insecticide procurement for vector control are made. The presence of 1014 S in An. gambiae s.l., in addition to 1014 F, is not unexpected given the recent report of 1014 S in Benin but highlights the importance of monitoring for both mutations throughout the continent. Future research must now focus on the impact that this resistance is having on malaria control in Burkina Faso.     

Changes in plant species diversity of aquatic ecosystems in the agricultural landscape in West Poland in the last 30 years

The aim of this study was to diagnose changes in species composition and their dynamics caused by human impact in aquatic and marsh vegetation in the contemporary agricultural landscape. The most serious threat was an increase in the nitrogen content of surface waters and groundwater which had resulted from the intensive management of the surrounding areas. Floristic data were collected in a lake, peaty pools and a drainage ditch within agricultural areas in the Wielkopolska region (West Poland) in 2006–2007, and compared with data from 1976–1980. The species richness had significantly increased and the shares of sociological and geographical–historical groups had changed clearly. This was reflected in an increase in the synanthropization index from 32.6 to 48.5. All the changes resulted from human impact, which had caused the acceleration of eutrophication in the water bodies. The natural plant succession, especially in the reed beds and sedge communities, was also accelerated due to human pressure. The vascular plant species richness in aquatic and marsh habitats increased by 40, because 15 species had disappeared and 55 new had appeared. However, six moss and four stonewort species had disappeared and only three new moss species were found. The increase in species richness did not raise the natural value of the flora, because the new species group is composed mainly of synanthropic species: native (apophytes) and alien, whereas all the lost species are endangered and rare native species (spontaneophytes), which occur only in natural or seminatural conditions. On the local scale, as species richness increases, plant communities lose their natural value. As an effect of synanthropization the stenotopic species disappear, while the widespread species spread even more. The increase in species richness is a consequence of appearance of species with a wide ecological scale that are not typical for aquatic ecosystems in patches of emergent vegetation. Finally, the species diversity of the whole landscape declines.