2013. február 28., csütörtök

Vadadi-Fülöp et al. (2012) Aquatic Ecology

Csaba Vadadi-Fülöp, Csaba Sipkay, Gergely Mészáros and Levente Hufnagel (2012): Climate change and freshwater zooplankton: what does it boil down to? Aquatic Ecology 46(4): 501-519. DOI: 10.1007/s10452-012-9418-8

Recently, major advances in the climate-zooplankton interface have been made some of which appeared to receive much attention in a broader audience of ecologists as well. In contrast to the marine realm, however, we still lack a more holistic summary of recent knowledge in freshwater. We discuss climate change-related variation in physical and biological attributes of lakes and running waters, high-order ecological functions, and subsequent alteration in zooplankton abundance, phenology, distribution, body size, community structure, life history parameters, and behavior by focusing on community level responses. The adequacy of large-scale climatic indices in ecology has received considerable support and provided a framework for the interpretation of community and species level responses in freshwater zooplankton. Modeling perspectives deserve particular consideration, since this promising stream of ecology is of particular applicability in climate change research owing to the inherently predictive nature of this field. In the future, ecologists should expand their research on species beyond daphnids, should address questions as to how different intrinsic and extrinsic drivers interact, should move beyond correlative approaches toward more mechanistic explanations, and last but not least, should facilitate transfer of biological data both across space and time.

Global warming, Daphnia, Phenology, Community dynamics, Ecological models

Horváth et al. (2012) Ecological Research

Horváth R., Magura T. & Tóthmérész B. (2012) Ignoring ecological demands masks the real effect of urbanization: a case study of ground-dwelling spiders along a rural-urban gradient in a lowland forest in Hungary. Ecological Research 27(6): 1069-1077. DOI: 10.1007/s11284-012-0988-7

We studied ground-dwelling spiders along a rural-suburban-urban forest gradient representing increasing human disturbance using pitfall traps. We tested four known and two novel hypotheses: (1) increasing disturbance hypothesis (species richness is decreasing by disturbance); (2) matrix species hypothesis (the richness of open-habitat species is increasing by disturbance); (3) opportunistic species hypothesis (the richness of generalist species is increasing by disturbance); and (4) habitat specialist hypothesis (the number of the forest specialist species is decreasing by disturbance). As a consequence of urbanization, urban forests become drier and more open; thus, according to the new hypotheses, the number of (5) xerophilous species and (6) light-preferring species are increasing in the urban area. Our result did not support the increasing disturbance hypothesis, as the overall species richness increased from the rural sites to the urban ones. As predicted, the number of both the open-habitat and the generalist species increased towards the urban sites. The number of forest specialist species was higher in the suburban area than in the rural and urban area. Both xerophilous and light-preferring species were the most numerous in the urban area, supporting the xerophilous species and the light-preferring species hypotheses. Canonical correspondence analysis showed that the forest specialist species associated with the rural sites with higher amounts of decaying woods and more herbs or with the suburban sites with higher cover of leaf litter and higher relative humidity. Two generalist species and one open-habitat species were characteristic of urban sites with higher ground surface and air temperature.

Globenet, Disturbance, Xerophilous species, Light-preferring species, Environmental factors

Szövényi et al. (2012) Molecular Ecology

Szövényi, P., Sundberg, S. and Shaw, A. J. (2012), Long-distance dispersal and genetic structure of natural populations: an assessment of the inverse isolation hypothesis in peat mosses. Molecular Ecology, 21: 5461–5472. doi: 10.1111/mec.12055

It is well accepted that the shape of the dispersal kernel, especially its tail, has a substantial effect on the genetic structure of species. Theory predicts that dispersal by fat-tailed kernels reshuffles genetic material, and thus, preserves genetic diversity during colonization. Moreover, if efficient long-distance dispersal is coupled with random colonization, an inverse isolation effect is predicted to develop in which increasing genetic diversity per colonizer is expected with increasing distance from a genetically variable source. By contrast, increasing isolation leads to decreasing genetic diversity when dispersal is via thin-tailed kernels. Here, we use a well-established model group for dispersal biology (peat mosses: genus Sphagnum) with a fat-tailed dispersal kernel, and the natural laboratory of the Stockholm archipelago to study the validity of the inverse isolation hypothesis in spore-dispersed plants in island colonization. Population genetic structure of three species (Sphagnum fallax, Sphagnum fimbriatum and Sphagnum palustre) with contrasting life histories and ploidy levels were investigated on a set of islands using microsatellites. Our data show (, amova, IBD) that dispersal of the two most abundant species can be well approximated by a random colonization model. We find that genetic diversity per colonizer on islands increases with distance from the mainland for S. fallax and S. fimbriatum. By contrast, S. palustre deviates from this pattern, owing to its restricted distribution in the region, affecting its source pool strength. Therefore, the inverse isolation effect appears to hold in natural populations of peat mosses and, likely, in other organisms with small diaspores.

genetic structure,inverse isolation hypothesis,island colonization,long-distance dispersal,  Sphagnum

Scheuring & Douglas (2012) Ecology Letters

Scheuring, I., Douglas, W.Y. (2012) How to assemble a beneficial microbiome in three easy steps. Ecology Letters (2012) 15: 1300–1307. DOI: 10.1111/j.1461-0248.2012.01853.x

There is great interest in explaining how beneficial microbiomes are assembled. Antibiotic-producing microbiomes are arguably the most abundant class of beneficial microbiome in nature, having been found on corals, arthropods, molluscs, vertebrates and plant rhizospheres. An exemplar is the attine ants, which cultivate a fungus for food and host a cuticular microbiome that releases antibiotics to defend the fungus from parasites. One explanation posits long-term vertical transmission of Pseudonocardia bacteria, which (somehow) evolve new compounds in arms-race fashion against parasites. Alternatively, attines (somehow) selectively recruit multiple, non-coevolved actinobacterial genera from the soil, enabling a multi-drug strategy against parasites. We reconcile the models by showing that when hosts fuel interference competition by providing abundant resources, the interference competition favours the recruitment of antibiotic-producing (and -resistant) bacteria. This partner-choice mechanism is more effective when at least one actinobacterial symbiont is vertically transmitted or has a high immigration rate, as in disease-suppressive soils.

Actinomycetes, antibiotics, Attini, game theory, horizontal transmission, microbiome, mutualism, screening, Streptomyces, symbiosis

2013. február 14., csütörtök

Ferincz et al. (2012) Acta Zoologica Academiae Scientiarum Hungaricae

This analysis of long-term (1992–2011) changes in the fish assemblage of the partially operating shallow, hypertrophic reservoir (Ingói-marsh, Lake Fenéki) was carried out on the occasion of the planned completion of the impoundment. Samplings were performed in standard localities with electrofishing. Three phases could be distinguished in fish fauna development. The first phase is characterized by two allochtonous marsh-species: the Mud-minnow (Umbra krameri) and the Crucian carp (Carassius carassius), and was fast replaced by the second invasion phase, characterized by the invasion of non-native gibel carp (Carassius gibelio),and the third phase by the dominance of roach (Rutilus rutilus) and bleak (Alburnus alburnus). The cumulative relative abundance of non-indigenous species reached a peak in the third year of the impoundment (1995; 56.4%), and remained high (>>50%) until 2001. The number of species, Shannon-Weaver diversity, and relative abundance of piscivorous species correlated positively with the age of reservoir. The shift of the fish fauna between the two phases was dynamic and dramatic, since the all previously dominant species disappeared within 4 years. The impact of invasive gibel carp is considered as high, because it has completely replaced its native relative (C. carassius), but in the other hand it only was able to delay the natural successive process, not completely transform it.

gibel carp, diversity, assemblage structure, shallow reservoir

2013. február 5., kedd

Kelemen et al. (2013) Journal of Vegetation Science

Kelemen, K., Kriván, A., Standovár, T. (2013): Effects of land-use history and current management on ancient woodland herbs in Western Hungary. Journal of Vegetation Science. doi: 10.1111/jvs.12046

Questions: At least half of the European woodland is recent and most stands have been under heavy management since the Industrial Revolution. Woodland herbs have adapted to the conditions of the forest interior and many species occur at lower frequencies in recent habitats as well as in young stands. We compared herbaceous plant composition of forests with different land-use history and looked for life-history traits that could be responsible for the differences.
Location: Bakony Mountains, Western Hungary, Central Europe.
Methods: Adjacent old ancient, young ancient and post-agricultural recent forest stands were surveyed in the submontane beech zone in Western Hungary. Frequency data were recorded for herbaceous plants, indicator species analysis was carried out and trait-based species groups were identified.
Results: Species composition differed among all three categories. The most profound difference was in the occurrences of ancient forest species (species with low dispersal ability and early flowering). These were most abundant in old ancient forests, while three species were entirely missing from recent stands. Young stands were dominated by few shade-tolerant herbs and lacked most ancient forest species. Post-agricultural woodland was largely dominated by competitive species.
Conclusions: Current forest management as well as past agricultural use influenced herb composition. Reintroduction of ancient forest herbs might be necessary in the recent forests.
Ancient forest, Dispersal limitation, Life-history trait, Post-agriculture, Recent forest, Spring geophyte

2013. február 3., vasárnap

Batáry et al. (2013) PLOS One

Batáry P, Sutcliffe L, Dormann CF, Tscharntke T (2013) Organic Farming Favours Insect-Pollinated over Non-Insect Pollinated Forbs in Meadows and Wheat Fields. PLoS ONE 8(1): e54818. doi:10.1371/journal.pone.0054818

The aim of this study was to determine the relative effects of landscape-scale management intensity, local management intensity and edge effect on diversity patterns of insect-pollinated vs. non-insect pollinated forbs in meadows and wheat fields. Nine landscapes were selected differing in percent intensively used agricultural area (IAA), each with a pair of organic and conventional winter wheat fields and a pair of organic and conventional meadows. Within fields, forbs were surveyed at the edge and in the interior. Both diversity and cover of forbs were positively affected by organic management in meadows and wheat fields. This effect, however, differed significantly between pollination types for species richness in both agroecosystem types (i.e. wheat fields and meadows) and for cover in meadows. Thus, we show for the first time in a comprehensive analysis that insect-pollinated plants benefit more from organic management than non-insect pollinated plants regardless of agroecosystem type and landscape complexity. These benefits were more pronounced in meadows than wheat fields. Finally, the community composition of insect-pollinated and non-insect-pollinated forbs differed considerably between management types. In summary, our findings in both agroecosystem types indicate that organic management generally supports a higher species richness and cover of insect-pollinated plants, which is likely to be favourable for the density and diversity of bees and other pollinators.