Patterns of bacterial diversity in embryonic capsules of the spotted salamander Ambystoma maculatum: an expanding view of a symbiosis

ABSTRACT The unicellular green alga, Oophila amblystomatis, populates egg capsules of the spotted salamander Ambystoma maculatum. This nutrient-exchange mutualism is widely perceived as a bipartite interaction, but the presence and contributing effects of bacteria to this symbiosis are unknown. We used standard cultivation techniques and amplicon sequencing of the V4/V5 region of 16S rRNA gene to identify and compare diversity of bacterial taxa in embryonic capsules with that in the aquatic breeding habitat. Our sampling regime allowed us to investigate diversity among individual capsules of an egg mass and between two ponds and sampling years. Capsules contain much lower diversity of bacteria than pond water, and spatial and temporal variation in intracapsular and pond bacterial diversity was observed. Despite this variation, sequences corresponding to species in the orders Burkholderiales and Oligoflexales were either prevalent or abundant, or both. Isolates most commonly recovered from capsules were closely related to species in the genus Herbaspirillum (Burkholderiaceae); other isolates were pseudomonads, but in all cases are closely related to known vascular plant-associated species. We conclude that, despite observed variation, there are bacterial taxa whose presence is held in common spatially and temporally among capsules and that the symbiosis between O. amblystomatis and A. maculatum may involve these taxa.

Microgeographic divergence of functional responses among salamanders under antagonistic selection from apex predators

A predator's functional response determines predator–prey interactions by describing the relationship between the number of prey available and the number eaten. Its shape and parameters fundamentally govern the dynamic equilibrium of predator–prey interactions and their joint abundances. Yet, estimates of these key parameters generally assume stasis in space and time and ignore the potential for local adaptation to alter feeding responses and the stability of trophic dynamics. Here, we evaluate if functional responses diverge among populations of spotted salamander ( Ambystoma maculatum ) larvae that face antagonistic selection on feeding strategies based on their own risk of predation. Common garden experiments revealed that spotted salamander from ponds with varying predation risks differed in their functional responses, suggesting an evolutionary response. Applying mechanistic equations, we discovered that the combined changes in attack rates, handling times and shape of the functional response enhanced feeding rate in environments with high densities of gape-limited predators. We suggest how these parameter changes could alter community equilibria and other emergent properties of food webs. Community ecologists might often need to consider how local evolution at fine scales alters key relationships in ways that alter local diversity patterns, food web dynamics, resource gradients and community responses to disturbance.

Ecological analysis of faunal complexes western region of Ukraine

The paper present result of research on the ecological analysis of faunal complexes of the Western region of Ukraine. The animal world of this region is distinct from the other zones. The variety of the landscape determines the variety of the animal world. Ukrainian Carpathians are one of the last area in continental Europe to support viable populations of large carnivores. Established that the endemic to the Western region of Ukraine are carpathian squirrel, carpathian newt, spotted salamander, golden eagle. The most rare animals are: bison, brown bear, lynx, golden eagle, white-tailed eagle, common muskrat, european gopher, forest cat. The Brown bear population in the Ukrainian Carpathian reach approximately 150–200 individuals. The lynx population is officially estimated to be about 350–400 individuals. In Ukraine there are about 300 species of bison. Only 33 nimals left in Ukrainian Skolivsky Beskydy. We can also find noble deer, roe, wolf, moose, hare, squirrel, wild cats and pigs, hamster, field mouse and so on. Some fur animals (nutria, mink, silvery-black fox, muskrat, stone marten, badger) were brought in from afar, and they acclimatized themselves well to the environment. The diverse habitats in the Carpathians support a wide variety of bird species, using the region for nesting, migrating and wintering. Overall, more than 300 species are found in the Zakarpattia. Bird life includes golden eagles and black wood peckers, carrion eagle, black griffons, white-tailed eagle, sparrow, titmouse, owls, gulls, partridge. The golden eagle nests in all the major mountains of Europe, in the Ukrainian Carpathians – 10–15 pairs. The rivers and lakes are home to ducks, geese, storks, swans and cranes. Rivers, lakes and manmade reservoirs of the Western region of Ukraine are inhabited with perch, bream, zander, pike, crucian carp, sazan, carp, sturgeon, trout. Among reptiles, one can come upon vipers, grass-snakes, and lizards. The spotted salamander and three types of tritons are entered in the Red Book. It was found that the most Red species are in Zakarpattia (168) and the least – in Rivne (85 species). The main factors of influence on the biodiversity of the Western region of Ukrain are identified. It is shown that poaching, anthropogenic and recreational activities have the most influence on faunal complex studied region.