Kovács (2012) Acta Zoologica Academiae Scientiarum Hungaricae

Kovács, Zs. E. (2012): Dispersal history of an invasive rodent in Hungary – subfossil finds of Rattus rattus. Acta Zoologica Academiae Scientiarum Hungaricae 58 (4): 379–394.

Abstract
The origins of the black rat Rattus rattus can be placed in the Indian Peninsula and its occurrence in Europe is a result of a westward expansion. Based on archaeozoological finds, this rodent came into the Mediterranean and other parts of Europe before the Roman Period, as a commensal species associated with trade, although it was also introduced in many other parts of the continent during that time. After a depression in the population there is an increase in number of rat finds dating to the 11th century in Europe. The same tendency was observed in Hungary. The earliest rat remains in the country were recovered from sites dated to the Roman period (3–4th century AD) from inside and outside the territory of the Empire as well. Remains outside the limes (the border of the empire running along the right bank of the Danube) indicate that the Danube River did not pose a barrier in the expansion of rats. Records from the Roman period were followed by a gap of ca. 1000 years when the appearance of black rat was detected again at medieval Hungarian sites (from the 14th century onwards) reaching large numbers at sites dated to the Ottoman period (16–17th century).


Keywords
Hungary, archaeozoology, black rat, expansion routes, flotation

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

Purger, J. J., Kurucz, K., Csuka, Sz. and Batáry, P. (2012): Do different plasticine eggs in artificial ground nests influence nest survival? Acta Zoologica Academiae Scientiarum Hungaricae 58 (4): 369–378.


Abstract
In order to understand the role of plasticine eggs in nest predation studies, altogether 78 ground nests were monitored in a large wheat field near to Pécs (southern Hungary) in June 2006. Two eggs were placed in each of the artificial nests, comprising, in an alternating sequence, quail + quail, quail + natural colour plasticine, and quail + white lime coloured plasticine eggs. During one week 65.4% of the artificial nests were depredated. When the damage or disappearance of any of the eggs was considered as a predation event, the daily survival rates of nest containing only two quail eggs was higher than of nests with quail and natural plasticine eggs and significantly higher than of nests with quail and white coloured plasticine eggs. When considering predation to real eggs only, the results remained similar, however, the significant difference in survival rates of the two nest types with different plasticine eggs disappeared. Simultaneously with the nest predation experiments, 78 small mammal live traps were set up in the wheat field and operated for 7 nights. The capture success of traps baited with quail egg was 9.9%, with natural plasticine egg 15.4%, and with white coloured plasticine egg 23.1%, but only a marginal significant difference was found between daily survival rates of quail vs. white coloured plasticine eggs. Natural, but especially white coloured plasticine eggs resulted in an increased predation rate, therefore we suggest that in artificial ground nest experiments nest should be considered to be predated only when the real egg is damaged or disappeared.


Keywords
Coturnix coturnix, nest predation, small mammals, live traps, Hungary

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

Plaiasu, R., Vörös, J. and Bancila, R.(2012): Fluctuating asymmetry as a tool in identifying population stress in Hungarian populations of Bombina bombina, B. variegata and their hybrids. Acta Zoologica Academiae Scientiarum Hungaricae 58 (4): 361–368.

Abstract
Hybridization can occur under natural conditions among well-differentiated species and may affect the developmental stability of hybrids. In the present study, we investigated the effect of interspecific hybridization between Bombina bombina and B. variegata on fluctuating asymmetry (FA) of forelimb, femur, tibia and foot. The hybrids did not show higher levels of FA compared to the parental populations for either investigated traits. This suggested that the effect of hybridization on FA in the analyzed traits is negligible or overwhelmed by other factors. A significantly increased FA was found in the B. bombina populations when compared to B. variegata, which can be attributed to low pressure of natural selection in these populations.


Keywords
interspecific hybridization, Bombina, fluctuating asymmetry

Cseresnyés & Csontos (2012) Acta Botanica Croatica

Imre Cseresnyés, Péter Csontos (2012): Soil seed bank of the invasive Robinia pseudoacacia in planted Pinus nigra stands. Acta Botanica Croatica 71 (2): 249–260.


Abstract
Pinus nigra and Robinia pseudoacacia are exotic trees used for afforestation in Hungary. Pinus nigra was non-invasive, howeverR. pseudoacacia escaped from cultivation and invaded several vegetation types including pine plantations. It has recently been planned to cut P. nigra plantations and replace them by native tree stands, especially in nature reserves. The scattered presence of R. pseudoacacia specimens in pine stands might place constraints on planned tree replacement because of their vegetative resproutingand recolonization from an established seed bank. The aim of this study was to investigate the soil seed bank under the canopy of solitary R. pseudoacacia specimens found in P. nigra plantations. Altogether 250 soil samples were collected from the 0–6 and 6–12 cmsoil layers under solitary Robinia trees of varying ages (with basal areas between 62.4 and 1089.3 cm2). Seeds were separated by sieving then scarified and germinated. Seed bank density ranged between 640 and 2285 seedsm–2 with an average distribution of 82.7% and 17.3% in the upper and lower soil layer, respectively. Total density of the seed bank and also the seed bank ratio of the lower soil layer increased with tree age. The accumulated seed bank of R. pseudoacacia should be considered in the careful planning of tree replacement operations in Pinus nigra stands.


Keywords
Afforestation, dormancy, Pinus nigra, plantation, Robinia pseudoacacia, seed germination, soil seed bank

Batáry et al. (2012) Community Ecology

P. Batáry, A. Kovács-Hostyánszki, C. Fischer, T. Tscharntke & A. Holzschuh (2012): Contrasting effect of isolation of hedges from forests on farmland vs. woodland birds. Community Ecology 13(2): 155-161.

Abstract

Hedges and forest edges play a major role in providing nesting sites, food resources and shelter for birds in agricultural landscapes of western and central Europe. We investigated the response of farmland vs. woodland birds at two degrees of isolation of hedges from forest and to vegetation structure. We surveyed 200 m long sections of six forest edges, six hedges connected to forests and six isolated hedges. Species richness and abundance of farmland birds were higher in hedges than in forest edges, species richness and abundance of woodland birds were lower in hedges than in the forest edges. Species richness and abundance of both groups did not differ between connected and isolated hedges. Width and height of hedges and edges did not affect the species richness and abundance of either farmland or woodland birds. Furthermore, bird community composition differed between habitat types (hedge vs. forest edge) and also between hedge isolation levels (hedges connected to forest vs. isolated hedges). Based on our results, we emphasize the importance of hedges in conserving farmland birds and encourage policy makers to support hedge creation and maintenance with landscape-wide management strategies supporting a diverse hedge structure. Both connected and isolated hedges play an important role as they harbour different bird communities.

Keywords

Abundance, Community composition, Connectivity, Forest edge, Species richness

Møller et al. (2012) Oecologia

Anders Pape Møller, Mario Diaz, Einar Flensted-Jensen, Tomas Grim, Juan Diego Ibáñez-Álamo, Jukka Jokimäki, Raivo Mänd, Gábor Markó, Piotr Tryjanowski (2012): High urban population density of birds reflects their timing of urbanization. Oecologia 170(3): 867-875.

Abstract
Living organisms generally occur at the highest population density in the most suitable habitat. Therefore, invasion of and adaptation to novel habitats imply a gradual increase in population density, from that at or below what was found in the ancestral habitat to a density that may reach higher levels in the novel habitat following adaptation to that habitat. We tested this prediction of invasion biology by analyzing data on population density of breeding birds in their ancestral rural habitats and in matched nearby urban habitats that have been colonized recently across a continental latitudinal gradient. We estimated population density in the two types of habitats using extensive point census bird counts, and we obtained information on the year of urbanization when population density in urban habitats reached levels higher than that of the ancestral rural habitat from published records and estimates by experienced ornithologists. Both the difference in population density between urban and rural habitats and the year of urbanization were significantly repeatable when analyzing multiple populations of the same species across Europe. Population density was on average 30 % higher in urban than in rural habitats, although density reached as much as 100-fold higher in urban habitats in some species. Invasive urban bird species that colonized urban environments over a long period achieved the largest increases in population density compared to their ancestral rural habitats. This was independent of whether species were anciently or recently urbanized, providing a unique cross-validation of timing of urban invasions. These results suggest that successful invasion of urban habitats was associated with gradual adaptation to these habitats as shown by a significant increase in population density in urban habitats over time.


Keywords
Adaptation, Birds, Cross-validation, Invasion, Population density

Walker et al. (2012) Journal of Statistical Software

Steven C. Walker, Guillaume Guénard, Péter Sólymos, Pierre Legendre (2012): Multiple-Table Data in R with the multitable Package. 51 (8), http://www.jstatsoft.org/v51/i08/

Abstract
Data frames are integral to R. They provide a standard format for passing data to model-fitting and plotting functions, and this standard makes it easier for experienced users to learn new functions that accept data as a single data frame. Still, many data sets do not easily fit into a single data frame; data sets in ecology with a so-called fourth- corner problem provide important examples. Manipulating such inherently multiple-table data using several data frames can result in long and difficult-to-read workflows. We introduce the R multitable package to provide new data storage objects called data.list objects, which extend the data.frame concept to explicitly multiple-table settings. Like data frames, data lists are lists of variables stored as vectors; what is new is that these vectors have dimension attributes that make accessing and manipulating them easier. As data.list objects can be coerced to data.frame objects, they can be used with all R functions that accept an object that is coercible to a data.frame.

Keywords
data organization, ecology, fourth-corner problem, R

Csősz et al. (2012) Journal of Insect Science

Csősz S, Lapeva-Gjonova A, Markó B. (2012): New data on the geographical distribution and host utilization of the entomopathogenic fungus Myrmicinosporidium durum. Journal of Insect Science 12:129.

Abstract
Entomopathogenic Myrmicinosporidium durum Hölldobler, 1933, a fungus known to exploit several ant species, is reported for the first time in five countries: Bulgaria, the Czech Republic, Romania, Slovakia, and Turkey. The discovery of the fungus in Anatolia significantly widens its known distribution. In addition, this fungal parasite was found to utilize two hitherto unknown host species: Tetramorium sp. D (sensu Schlick-Steiner et al. 2006) and Tetramorium sp. E (sensu Schlick-Steiner et al. 2006). According to the new data, M. durumseems to be more common in Europe than previously thought, while its host range is considerably larger. In the present paper, data on its currently known distribution and host preference are discussed.


Keywords
biodiversity, disease, fungal, host ant, parasitism, pathogen

Matsuoka et al. (2012) Auk

Matsuoka, S. M., Bayne, E. M., Sólymos, P., Fontaine, P., Cumming, S. G., Schmiegelow, F. K. A., & Song, S. A. (2012): Using binomial distance-sampling models to estimate the effective detection radius of point-counts surveys across boreal Canada. Auk 129: 268-282.

Abstract

We used binomial distance-sampling models to estimate the effective detection radius (EDR) of point-count surveys across boreal Canada. We evaluated binomial models based on 0–50 m and >50 m distance categories for goodness-of-fit and sensitivities to variation in survey effort and habitats sampled. We also compared binomial EDRs to Partners in Flight’s maximum detection distances (MDD) to determine differences in landbird population sizes derived from each. Binomial EDRs had a small positive bias (4%) averaged across 86 species and a large positive bias (30–82%) for two species when compared with EDRs estimated using multinomial distance sampling. Patterns in binomial EDRs were consistent with how bird songs attenuate in relation to their frequencies and transmission through different habitats. EDR varied 12% among habitats and increased 17% when birds were counted to an unlimited distance, compared with a limited distance of 100 m. The EDR did not vary with the duration of surveys, and densities did not differ when using unlimited-distance versus truncated data. Estimated densities, however, increased 19% from 3- to 5-min counts and 25% from 5- to 10-min counts, possibly from increases in the availability, movement, or double counting of birds with longer counts. Thus, investigators should be cautious when comparing distance-sampling results among studies if methods vary. Population sizes estimated using EDR averaged 5 times (0.8–15 times) those estimated with MDD. Survey data from which to estimate binomial EDRs are widely available across North America and could be used as an alternative to MDD when estimating landbird population sizes.
 

Keywords

binomial distance-sampling models, boreal forest birds, density estimation, detection probabilities, effective detection radius, point-count surveys, population size estimation

Sólymos et al. (2012) Environmetrics

Sólymos, P., Lele, S. R. & Bayne, E. (2012): Conditional likelihood approach for analyzing single visit abundance survey data in the presence of zero inflation and detection error. Environmetrics 23: 197-205.

Abstract

Current methods to correct for detection error require multiple visits to the same survey location. Many historical datasets exist that were collected using only a single visit, and logistical/cost considerations prevent many current research programs from collecting multiple visit data. In this paper, we explore what can be done with single visit count data when there is detection error. We show that when appropriate covariates that affect both detection and abundance are available, conditional likelihood can be used to estimate the regression parameters of a binomial–zero-inflated Poisson (ZIP) mixture model and correct for detection error. We use observed counts of Ovenbirds (Seiurus aurocapilla) to illustrate the estimation of the parameters for the binomial–zero-inflated Poisson mixture model using a subset of data from one of the largest and longest ecological time series datasets that only has single visits. Our single visit method has the following characteristics: (i) it does not require the assumptions of a closed population or adjustments caused by movement or migration; (ii) it is cost effective, enabling ecologists to cover a larger geographical region than possible when having to return to sites; and (iii) its resultant estimators appear to be statistically and computationally highly efficient.

Keywords

closed populations, conditional likelihood, ecological monitoring, mixture models, open populations, pseudo-likelihood

Sólymos & Lele (2012) Global Ecology and Biogeography

Sólymos, P. & Lele, S. R. (2012): Global pattern and local variation in species-area relationships. Global Ecology and Biogeography 21: 109-120.

Abstract

Aim: We conducted a meta-analysis of species–area relationships (SARs) by combining several data sets and important covariates such as types of islands, taxonomic groups, latitude and spatial extent, in a hierarchical model framework to study global pattern and local variation in SARs and its consequences for prediction.
Location: One thousand nine hundred and eighteen islands from 94 SAR studies from around the world.
Methods: We developed a generalization of the power-law SAR model, the HSARX model, which allows: (1) the inclusion of multiple focal parameters (intercept, slope, within-study variance), (2) use of multiple effect modifiers based on a collection of SAR studies, and (3) modelling of the between- and within-study variability.
Results: The global pattern in the SAR was the average of local SARs and had wide confidence intervals. The global SAR slope was 0.228 with 90% confidence limits of 0.059 and 0.412. The intercept, slope and within-study variability of local SARs showed great heterogeneity as a result of the interaction of modifying covariates. Confidence intervals for these SAR parameters were narrower when other covariates in addition to area were accounted for, thus increasing the accuracy of the predictions for species richness. The significant effect of latitude and the interaction of latitude, taxa and island type on the SAR slope indicated that the ‘typical’ latitudinal diversity gradient can be reversed in isolated systems.
Main conclusions: The power-law relationship underlying the HSARX model provides a good fit for non-nested SARs across vastly different spatial scales by taking into account other covariates. The HSARX framework allows researchers to explore the complex interactions among SAR parameters and modifying variables, to explicitly study the scale dependence, and to make robust predictions on multiple levels (island, study, global) with associated prediction intervals. From a prediction perspective, it is not the global pattern but the local variation that matters.

Keywords

Beta diversity, data cloning, empirical Bayes, hierarchical model, islands, latitudinal diversity gradient, maximum likelihood, prediction, prognosis, species–area relationship

Mayor et al. (2012) Nature Communications

Mayor, S.J., Cahill, J.F., He, F., Sólymos, P. & Boutin, S. (2012): Regional boreal biodiversity peaks at intermediate human disturbance.Nature Communications, 3: 1142, DOI: 10.1038/ncomms2145

Abstract

The worldwide biodiversity crisis has intensified the need to better understand how biodiversity and human disturbance are related. The 'intermediate disturbance hypothesis' suggests that disturbance regimes generate predictable non-linear patterns in species richness. Evidence often contradicts intermediate disturbance hypothesis at small scales, and is generally lacking at large regional scales. Here, we present the largest extent study of human impacts on boreal plant biodiversity to date. Disturbance extent ranged from 0 to 100% disturbed in vascular plant communities, varying from intact forest to agricultural fields, forestry cut blocks and oil sands. We show for the first time that across a broad region species richness peaked in communities with intermediate anthropogenic disturbance, as predicted by intermediate disturbance hypothesis, even when accounting for many environmental covariates. Intermediate disturbance hypothesis was consistently supported across trees, shrubs, forbs and grasses, with temporary and perpetual disturbances. However, only native species fit this pattern; exotic species richness increased linearly with disturbance.