Boda & Csabai (2012) Hydrobiologia

P. Boda, Z. Csabai (2012): When do beetles and bugs fly? A unified scheme for describing seasonal flight behaviour of highly dispersing primary aquatic insects. Hydrobiologia, online open

DOI: 10.1007/s10750-012-1350-3

Abstract

Changes of seasonal dispersal flight were investigated based on a wide spectrum of aquatic Heteroptera and Coleoptera species. We hypothesized that species or groups of species can be characterized by various seasonal patterns of dispersal flight. Dispersal activity was studied in a lowland marsh located in NE Hungary during a 30-week long monitoring period. Insects were attracted to highly polarising horizontal shiny black plastic sheets laid onto the ground. There are no periods of the year (from April till October) when insects are not rising into the air, but species have various seasonal flight activity. Dispersal flight activity of 45 species could be described. These activities assessed based on a seasonal approach and proportional classification. Based on these results, three seasonal patterns and twelve sub-patterns were defined. Comparing the observed patterns with previously reported dispersal activity data, we argue that observations found in the literature fit well with patterns defined here, therefore, to assess the dispersal behaviour, a unified scheme can be established. Owing to this unified scheme, the seasonal dispersal activity of primary aquatic insects observed in different studies becomes highly comparable. This scheme can be a useful tool for assessing dispersal behaviour of insects across other geographic regions.

Keywords

Flight behaviour, Seasonal patterns, Year-long dispersal, Polarotaxis, Coleoptera, Heteroptera

Horváth et al. (2012) Hydrobiologia

Hajnalka Horváth, Kálmán Mátyás, György Süle & Mátyás Présing (2012): Contribution of nitrogen fixation to the external nitrogen load of a water quality control reservoir (Kis-Balaton Water Protection System, Hungary). Hydrobiologia, online first

Abstract

To reduce external nutrient loading by the greatest nutrient transporter to Lake Balaton, the Kis-Balaton Water Protection System commenced operation in 1985. Cyanobacterial blooms (Cylindrospermopsis raciborskii, Aphanizomenon sp. and Anabaena sp.) cause N-loading via nitrogen fixation, which can exceed the total external N-load to the reservoir during the summer. Nitrogen fixation of phytoplankton in the system in 2009 was measured using the ¹⁵N-isotope technique. The light dependence of fixation was described by an exponential saturated curve which was then used to calculate daily nitrogen fixation. The total amount of nitrogen fixed during summer months (July–August) exceeded 170 t for the 21 km² of open water area, which was more than three times higher than the external load by inflows. Total nitrogen:total phosphorus mass ratios (2.5–11.5) favoured the development of a N₂-fixing cyanobacterial bloom, the contribution of which to the total algae biomass varied between 50 and 90%. The estimated primary production of phytoplankton was used to calculate the contribution of nitrogen fixation (0.01–28%) to algae N-demand. Nitrogen fixing cyanobacteria were found to play a key role in addressing the N-demand of phytoplankton. 

Keywords

Cyanobacteria, N₂-fixation, ¹⁵N-methodology, Nutrient ratio, Shallow water, Water quality control reservoir 

Ludwig et al. (2012) Acta Oecologica

Martin Ludwig, Hella Schlinkert, Andrea Holzschuh, Christina Fischer, Christoph Scherber, Alfréd Trnka, Teja Tscharntke, Péter Batáry (2012): Landscape-moderated bird nest predation in hedges and forest edges. Acta Oecologica 45: 50–56.

http://dx.doi.org/10.1016/j.actao.2012.08.008

Abstract

Landscape-scale agricultural intensification has caused severe declines in biodiversity. Hedges and forest remnants may mitigate biodiversity loss by enhancing landscape heterogeneity and providing habitat to a wide range of species, including birds. However, nest predation, the major cause of reproductive failure of birds, has been shown to be higher in forest edges than in forest interiors. Little is known about how spatial arrangement (configuration) of hedges affects the avian nest predation. We performed an experiment with artificial ground and elevated nests (resembling yellowhammer and whitethroat nests) baited with quail and plasticine eggs. Nests were placed in three habitat types with different degrees of isolation from forests: forest edges, hedges connected to forests and hedges isolated from forests. Nest predation was highest in forest edges, lowest in hedges connected to forests and intermediate in isolated hedges. In the early breeding season, we found similar nest predation on ground and elevated nests, but in the late breeding season nest predation was higher on ground nests than on elevated nests. Small mammals were the main predators of ground nests and appeared to be responsible for the increase in predation from early to late breeding season, whereas the elevated nests were mainly depredated by small birds and small mammals. High predation pressure at forest edges was probably caused by both forest and open-landscape predators. The influence of forest predators may be lower at hedges, leading to lower predation pressure than in forest edges. Higher predation pressure in isolated than connected hedges might be an effect of concentration of predators in these isolated habitats. We conclude that landscape configuration of hedges is important in nest predation, with connected hedges allowing higher survival than isolated hedges and forest edges.

Highlights

► We performed an experiment with artificial nests in hedges and forest edges. ► Connected hedges allowed higher survival than isolated hedges and forest edges. ► Nest predation on ground and elevated nests was similar in early breeding season. ► In late breeding season nest predation was higher on ground than on elevated nests. ► Landscape configuration of hedges is important in nest predation.

Keywords

Artificial nest, Elevated nest, Ground nest, Hedgerow, Mayfield survival rate, Plasticine egg

Veres et al. (2012) Agriculture, Ecosystems & Environment

Andrea Veres, Ferenc Tóth, József Kiss, Kinga Fetykó, Szilvia Orosz, Claire Lavigne, Stefan Otto, David Bohan (2012): Spatio-temporal dynamics of Orius spp. (Heteroptera: Anthocoridae) abundance in the agricultural landscape. Agriculture, Ecosystems & Environment 162(1): 45–51.

DOI: 10.1016/j.agee.2012.08.009

Abstract

Predators of the genus Orius are widely released as control agents against Frankliniella occidentalis, however they can also colonize crops spontaneously, and conservation biological control can potentially take advantage of the presence of semi-natural areas in the agricultural landscape. A three-year study was conducted in Hungary in order to evaluate the Orius species spatial pattern at landscape scale, and to link their eventual aggregation, i.e. higher abundance, to the presence of semi-natural areas, which has been shown to benefit conservation biological control in general. Results show that Orius species population size and spatial pattern are related to semi-natural areas, and that influences with other agro-environmental factors exist. Orius niger abundance is likely to be associated with semi-natural areas, where it can successfully overwinter, but also with other resources in the landscape, especially in warm years. As a consequence of O. niger being a habitat generalist we suggest that at landscape scale its abundance pattern is driven by resource patterns and availability of both semi-natural and cultivated areas. Furthermore, their population dynamics is influenced by crop management intensity rather than crop composition of cropping systems.

Highlights
► O. niger abundance is likely associated with semi-natural areas. ► Effective conservation biological control is expected mainly in warm years. ► Mass reproduction of O. niger is linked to arable fields and general resource patterns.

Keywords

Conservation biological control, GIS, Natural enemy, Greenhouse sweet pepper, Minute pirate bug

Baráth & Csiky (2012) Acta Botanica Croatica

Kornel Barath, Janos Csiky (2012): Host range and host choice of Cuscuta species in Hungary. Acta Botanica Croatica 71(2): 215-227.

Abstract
Extensive field studies were carried out in Hungary to get a picture of the hostrange and host choice of the Cuscuta species under natural conditions. We examined both parasitised and unparasitised plant species and found some aspects in which they are different. Compiling the host spectra of the various Cuscuta species based on herbaria, literature and our own observations, we can say that dodders infest at least 26% of the vascular flora of the country. In our study, the Hungarian Cuscuta species parasitised allplants that had a coverage of more than 25% in the sampling sites.We prepared a list of themost frequent host species for the parasites and revealed the importance of exclusive hosts. The results suggest that the habitat differences of the Cuscuta species can be responsible for the different host ranges. Furthermore, it was found that the reason why dodders parasitise plants from various life-forms in different proportions is not (only) the active host choice, but the characteristic features of the habitats.

Keywords
Cuscuta, parasitic plant, host, habitat

Botta-Dukát (2012) Journal of Vegetation Science

Botta-Dukát Z. (2012): Co-occurrence-based measure of species' habitat specialization: Robust, unbiased estimation in saturated communities. Journal of Vegetation Science 23(2): 201-207.

Abstract

Aims: Large vegetation plot databases enable the estimation of niche width from species co-occurrence data. Different indices have been proposed for this purpose, but do not give unbiased (i.e. independent of species pool size) and robust estimates over a wide range of conditions. The aims of the paper are to: (1) demonstrate the limitations of different methods, and (2) propose a new algorithm that results in unbiased and robust estimates.
Results: Whittaker's β-diversity, calculated from raw data, is an unbiased niche width measure only if the relationship between γ-diversity and local richness is linear. However, this requirement is satisfied only in specific conditions, if both γ-diversity and local richness are linear functions of the species pool size with zero intercept. I propose the use of Beals smoothing to estimate species pools. It has been proved through analysis of simulated data that Whittaker's β calculated from species pool data is an unbiased estimate of niche width. I have shown that the robustness of the estimate can be improved by excluding extremely species-rich plots. The relative role of methodological decisions during niche width estimation was explored through analysis of a large field data set (>8000 relevés).
Conclusions: The proposed algorithm results in robust, unbiased estimation, even in saturated communities, thus it avoids the drawbacks of the co-occurrence-based niche width measures proposed earlier.

Keywords 

Generalists, Niche width, Saturation, Simulation, Specialists, Species pool, Whittaker's β, β-diversity

Czúcz et al. (2012) Journal for Nature Conservation

Czúcz B., MolnárZs, Horváth F, Nagy G G, Botta-Dukát Z, Török K (2012): Using the natural capital index framework as a scalable aggregation methodology for local and regional biodiversity indicators. Journal for Nature Conservation 20 (3):144-152.

Abstract

There is an increasing need for aggregated biodiversity indicators to inform policy decisions at all levels from local to global. Despite their similar policy goals, low-level (e.g. local, regional) and high-level (e.g. continental, global) indicator development is generally performed independently, and the resulting indicators are often incompatible both in their structure and data requirements. In this paper we focus on a particularly flexible aggregation framework originally developed for global assessments, the Natural Capital Index. We show that with the use of appropriate fine-scale data, the NCI framework can be applied in low-level policy contexts as well. To support this statement, we show that several established low-level indicators are essentially conforming to the NCI framework, and can be seen as existing low-level NCI implementations. The concept is illustrated with an implementation for Hungary, and the potential advantages and shortcomings of low level NCI implementations are discussed. NCI-based low level indicators can be implemented in any region, where a local indicator of ecological quality is systematically surveyed. Given the recent surge in monitoring activities worldwide, fuelled by global change and reporting obligations, fine-scale NCI implementations can become important additions to existing ecological state indicators useful in a wide range of local and regional policy contexts.

Keywords 

Biodiversity index, Habitat quality, Naturalness, Vegetation condition, Ecosystem services

Fenesi & Botta-Dukát (2012) Journal of Plant Ecology

Fenesi, A.; Botta-Dukát, Z. (2012): Phenotypic divergences induced by different residence time in invasive common ragweeds. Journal of Plant Ecology 5:174-181.

Abstract
Aims: Possible shifts in the phenotypic performance along invasive plants’ spreading route are rarely examined due to the discontinuous and incomplete records of exotic species. As the invasion history of common ragweed (Ambrosia artemisiifolia L.) is well documented in Hungary, its residence time is known for each location. By sampling a sequence of older to more recently established populations, we aimed to determine (i) whether there are phenotypic divergences along the historical spreading route of A.artemisiifolia; (ii) which traits are under selection during the invasion process and (iii) the extent of maternal effects on the individual's performance.
Methods: We used a hierarchical sampling design to collect seeds from 64 individuals belonging to eight sites in four residence time categories (seven populations along the historical spreading route of ragweed in Hungary and one recently invaded site in Romania). We selected four large and four small individual plants in each population to control for maternal effects. The offspring were reared in a common garden located in Romania. Five vegetative phenotypic traits were measured at the end of the experiments and used in the subsequent analysis (plant height, basal diameter, number of secondary axes, length of the longest secondary axis and biomass). To summarize the variation of these highly correlated traits, principal component analysis was performed first and then the important components were used in linear mixed effect models.
Important Findings: The residence time categories were significantly distinguished by the first component, which compresses the variation of all five measured traits. The measures gradually decrease from populations with the longest residence time (introduced more than 65 years ago) towards the most recently established populations (established less than 30 years ago). These differences might reflect the invasion history of the populations: the longer the residence time the higher the chance to develop relevant traits beneficial in invasion process. The size of the mother plant significantly influenced not only the seed mass (inversely) but also the adult performance of its offspring (directly).

Keywords 

Ambrosia artemisiifolia, maternal effect, phenotypic divergence, plant invasion, residence time