Habitat selection and foraging site fidelity in Caspian Terns (Hydroprogne caspia) breeding in the Baltic Sea

Habitat preferences and foraging strategies affect population-level space use and are therefore crucial to understanding population change and implementing spatial conservation and management actions. We investigated the breeding season habitat preference and foraging site fidelity of the under-studied and threatened, Baltic Sea population of Caspian Terns (Hydroprogne caspia). Using GPS devices, we tracked 20 adult individuals at two breeding colonies, in Sweden and Finland, from late incubation through chick-rearing. Analyzing foraging movements during this period, we describe trip characteristics for each colony, daily metrics of effort, habitat use, and foraging site fidelity. We found that daily time spent away from the colony increased throughout the season, with colony-level differences in terms of distance travelled per day. In general, terns selected shallow waters between 0–5 meters in depth with certain individuals using inland lakes for foraging. We show, for the first time, that individual Caspian Terns are faithful to foraging sites throughout the breeding season, and that individuals are highly repeatable in their strategies regarding foraging site fidelity. These results fill important knowledge gaps for this at-risk population, and extend our general knowledge of the breeding season foraging ecology of this widespread species.

Summer stream habitat preferences of Nunavik anadromous Arctic char (Salvelinus alpinus) fry and parr

Arctic char is a fish species known to occupy diverse habitats within the Arctic region. However, summer habitat use during the juvenile stage of the anadromous form is largely unknown. The present study aims to characterize fry and parr summer habitat preferences. Surveys were conducted by electrofishing, associated with physical habitat characterization on several rivers of the Ungava Bay, Nunavik, Canada. At the microhabitat and station scales, fry showed significant habitat preferences for shallow water and slow velocity. At the mesohabitat scale, fry showed a significant habitat selectivity for riffles. This habitat selectivity implies that habitat models can be built to evaluate the potential of habitat suitability for Arctic char fry. However, no significant habitat selectivity was found for parr. Parr size was nonetheless positively correlated with velocity, which was found to be a limitative factor for juvenile habitat use. This first attempt at modeling juvenile anadromous Arctic char habitat in rivers emphasizes the importance of selecting an appropriate spatial scale and reiterates the fact that parr showed relatively high plasticity in stream habitat selection.

Desoria calderonis sp. nov., a new species of alpine cryophilic springtail (Collembola: Isotomidae) from the Apennines (Italy), with phylogenetic and ecological considerations

We describe and delimit with integrative taxonomy the new springtail species Desoria calderonis sp. nov. (Collembola: Isotomidae). This cryophilic species is strictly linked to the supraglacial stony debris of the isolated Calderone glacier (Central Apennines, Italy), one of the southernmost glaciers of Europe. Desoria calderonis sp. nov. could belong to the nivalis-complex, a group of European mountain species included in the violacea-group. Genetic analysis (COI mtDNA barcoding) confirms the morphological attribution to the genus Desoria Nicolet in Desor, 1841, but highlights that the genus, in its current definition, is polyphyletic. We specify the peculiar micro-habitat preferences and highlight the threat of extinction for this cryophilic species in the context of the ongoing climate change and subsequent risk of complete disappearance of the glacier.

Preliminary Assessment of the Diversity and Habitat Preferences of Herpetofauna in Cholistan Desert, Pakistan

This one-year survey was conducted from February 2017 to January 2018 to assess the herpetofaunal diversity in Cholistan desert, Bahawalnagar district, Punjab, Pakistan. Field surveys were conducted during dawn and dusk for fifteen consecutive days in alternate months and five sub sampling sites were sampled at ten field visits. Specimens were collected through hand capture, using snake sticks, forceps, drag nets, noose traps, pitfall and funnel traps. Overall, two species of toads, two species of frogs, two species of turtles, ten lizards species and ten snake species belonging to 23 genera and 14 families were recorded. Simpson index was calculated as 0.933, evenness 0.733 and Shannon – Wiener index was 2.947 indicating moderate to high level of diversity. Bufo stomaticus (Pi = 0.1253), Uromastyx hardwickii (Pi = 0.0739) were the dominant amphibian and reptilian species, respectively while Uromastyx asmussi was recorded for the first time in the study area. Hand capture and pitfall traps appeared to be the most effective methods to capture the amphibian and reptiles. The distribution ranges of amphibians and reptiles have changed and such surveys are necessary to update baseline information in the country. We recommend further systematic survey work and molecular analysis of the native species be undertaken in the future to supplement our findings.

Spatiotemporal variation in the adult sex ratio, male aggregation, and movement of two tropical cloud forest dung beetles

While theory suggests that at conception the sex ratio should be balanced (1:1), this can be variable across space and time in wild populations. Currently, studies of the environmental factors that regulate adult sex ratio (ASR) in species with different life-history traits are scarce. Using capture-recapture over a year, we analyzed the influence of habitat type (forest and non-forest) and season (rainy and dry) on variation in ASR, male aggregation and the trajectory movement of two dung beetle species with different life-history traits: Deltochilum mexicanum (a hornless roller species) and Dichotomius satanas (a tunneler species with horns on its head and thorax). We found opposite tendencies. The D. mexicanum population tends to be female-biased, but the population of D. satanas tends to be predominantly male, and observed values were not related to habitat type or season. However, the 95% confidence intervals estimated were highly variable between seasons depending on habitat. On examining the monthly variation in ASR for both habitats, we found that it depends on the species. In addition, male aggregation differed between species depending on habitat type and season, and species movement patterns were closely related to their habitat preferences. Based on our results, we argue that comparative population studies of species with different life-history traits are necessary to understand the variation in demographic parameters as well as its ecological and evolutionary implications in the face of spatial and climatic environmental variation.

The frequency method in studying habitat preferences of common forest birds

This paper presents the results of a study on the habitat preferences of selected species of the bird community in the Morgi Forest, the Kolbuszowa Forest Division (SE Poland), with the use of the point-stand bird census method. The aim of the study was to test the effectiveness of the method in determining the frequency of colonisation of stands with different habitat parameters by the most abundant bird species. In 270 tree stands of a forest complex with diverse habitats, a bird census was carried out with four counts per each stand. Next, a list of the tree stands and the bird species recorded in the stands was compiled. The stands were divided into categories according to the forest habitat type, dominant species and age class. In the next step, the occurrence frequency of the most abundant bird species was calculated for each stand category. Among the analysed species, the majority showed a positive correlation between the frequency of occurrence and habitat fertility. The influence of the dominant stand species on the occurrence frequency of bird species was largely driven by habitat fertility. The lowest average frequency of the identified avian species was found in stands dominated by pine Pinus sylvestris, birch Betula sp. and black alder Alnus glutinosa. There was generally a positive relationship between age class and the bird community parameters. It is concluded that the point-stand method of bird census provides informative results for research on the habitat selectivity of bird populations.

Rokubacteria in Northern Peatlands: Habitat Preferences and Diversity Patterns

Rokubacteria is a phylogenetic clade of as-yet-uncultivated prokaryotes, which are detected in diverse terrestrial habitats and are commonly addressed as members of the rare biosphere. This clade was originally described as a candidate phylum; however, based on the results of comparative genome analysis, was later defined as the order-level lineage, Rokubacteriales, within the phylum Methylomirabilota. The physiology and lifestyles of these bacteria are poorly understood. A dataset of 16S rRNA gene reads retrieved from four boreal raised bogs and six eutrophic fens was examined for the presence of the Rokubacteriales; the latter were detected exclusively in fens. Their relative abundance varied between 0.2 and 4% of all bacteria and was positively correlated with pH, total nitrogen content, and availability of Ca and Mg. To test an earlier published hypothesis regarding the presence of methanotrophic capabilities in Rokubacteria, peat samples were incubated with 10% methane for four weeks. No response to methane availability was detected for the Rokubacteriales, while clear a increase in relative abundance was observed for the conventional Methylococcales methanotrophs. The search for methane monooxygenase encoding genes in 60 currently available Rokubacteriales metagenomes yielded negative results, although copper-containing monooxygenases were encoded by some members of this order. This study suggests that peat-inhabiting Rokubacteriales are neutrophilic non-methanotrophic bacteria that colonize nitrogen-rich wetlands.