The oldest Pinus nigra plantations in the central Apennines: distribution and floristic-vegetational characterisation

This paper represents the first syntaxonomic study on the Pinus nigra subsp. nigra artificial stands in the Apennines. It refers exclusively to the mature Pinus nigra forest plantations in the central Apennines that were planted before the 1950s, and then not managed. The mature Pinus nigra forest plantations in the central Apennines are distributed within four National Parks, on limestone substrata, mainly with southern aspects and rugged slopes, and at elevations ranging from 655 m to 1670 m a.s.l.. Two new phytosociological associations are described here and classified in the alliance Junipero communis–Pinion nigrae: Orthilio secundae–Pinetum nigrae and Digitalidi micranthae–Pinetum nigrae. The association Orthilio secundae–Pinetum nigrae comprises the relative mesophilous mature pine forests of the supratemperate thermotype in the plant landscape context of the alliance Aremonio agrimonioidis–Fagion sylvaticae potential vegetation belt. The Digitalidi micranthae–Pinetum nigrae comprises the thermophilous pine forests occurring on rocky stands within mesotemperate and lower supratemperate thermotypes in the potential belt of alliance Carpinion orientalis woods. The comparison of these two new associations and the phytosociological literature concerning the natural communities of Pinus nigra in the Apennines highlights their floristic and coenological autonomy.

Local and collective transitions in sparsely-interacting ecological communities

Interactions in natural communities can be highly heterogeneous, with any given species interacting appreciably with only some of the others, a situation commonly represented by sparse interaction networks. We study the consequences of sparse competitive interactions, in a theoretical model of a community assembled from a species pool. We find that communities can be in a number of different regimes, depending on the interaction strength. When interactions are strong, the network of coexisting species breaks up into small subgraphs, while for weaker interactions these graphs are larger and more complex, eventually encompassing all species. This process is driven by emergence of new allowed subgraphs as interaction strength decreases, leading to sharp changes in diversity and other community properties, and at weaker interactions to two distinct collective transitions: a percolation transition, and a transition between having a unique equilibrium and having multiple alternative equilibria. Understanding community structure is thus made up of two parts: first, finding which subgraphs are allowed at a given interaction strength, and secondly, a discrete problem of matching these structures over the entire community. In a shift from the focus of many previous theories, these different regimes can be traversed by modifying the interaction strength alone, without need for heterogeneity in either interaction strengths or the number of competitors per species.

Mexican Coastal Dunes: Recipients and Donors of Alien Flora

The invasion of natural communities by exotic plants, which may turn into invasive or potentially invasive, is one of the most severe known threats to biodiversity, and coastal dunes are among the most affected habitats. Mexico’s coastal dunes are abundant and contain high plant biodiversity but attempts to determine the occurrence and impact of exotic plants are absent. First, we explored the number of invasive plant species found on Mexican coastal dunes. Second, we analyzed if the coastal dune flora native from Mexico acts as a source of invasive species worldwide. We found the relevant spread of exotic plants towards and from Mexico, reaching high percentages: 5% of the coastal dune flora are considered exotic plants; this increases to 8.7% when only plants typical of the coastal dune environment are considered. The Mexican coastal dunes flora is also a relevant source of invasive plants affecting all continents. Furthermore, almost half of the 35 worst worldwide invasive plants (according to the Global Invasive Species Database GISD) grow on Mexican coastal dunes, most native to Mexico and invasive elsewhere. Indeed, the worldwide exchange of coastal dune flora between Mexico and the world seems massive, relevant and highlights the need for worldwide and countrywide management and control strategies.

Marine Synechococcus picocyanobacteria: Light utilization across latitudes

The most ubiquitous cyanobacteria, Synechococcus, have colonized different marine thermal niches through the evolutionary specialization of lineages adapted to different ranges of temperature seawater. We used the strains of Synechococcus temperature ecotypes to study how light utilization has evolved in the function of temperature. The tropical Synechococcus (clade II) was unable to grow under 16 °C but, at temperatures >25 °C, induced very high growth rates that relied on a strong synthesis of the components of the photosynthetic machinery, leading to a large increase in photosystem cross-section and electron flux. By contrast, the Synechococcus adapted to subpolar habitats (clade I) grew more slowly but was able to cope with temperatures <10 °C. We show that growth at such temperatures was accompanied by a large increase of the photoprotection capacities using the orange carotenoid protein (OCP). Metagenomic analyzes revealed that Synechococcus natural communities show the highest prevalence of the ocp genes in low-temperature niches, whereas most tropical clade II Synechococcus have lost the gene. Moreover, bioinformatic analyzes suggested that the OCP variants of the two cold-adapted Synechococcus clades I and IV have undergone evolutionary convergence through the adaptation of the molecular flexibility. Our study points to an important role of temperature in the evolution of the OCP. We, furthermore, discuss the implications of the different metabolic cost of these physiological strategies on the competitiveness of Synechococcus in a warming ocean. This study can help improve the current hypotheses and models aimed at predicting the changes in ocean carbon fluxes in response to global warming.

Naturalists’ Hike As a New Form of Environmental Education for Children

The article highlights the experience of conducting a naturalist hike - a new form of organizing environmental education for preschoolers and primary schoolchildren. The purpose of the trip, carried out in the form of a travel game, meets the requirements for the formation of environmental literacy in children of this age group, which are stated in the standards of preschool and primary school education. Game “What can you see in a pine forest?” is intended to enrich the sensory experience of children in the process of observing plants and animals of the forest, to acquaint them with observation as a method of studying natural communities, to develop a cognitive interest in the flora and fauna of their native land, to foster a desire to protect the forest and its inhabitants by participating in nature conservation activities. The article is intended for preschool teachers, primary school teachers, and additional education specialists.

Ecosystem size and complexity are extrinsic drivers of food chain length in branching networks

Understanding the drivers of food chain length in natural communities has intrigued ecologists since the publication of ‘food cycles’ by Elton in the early 20th century. Proposed drivers of food chain length have included extrinsic controls such as productivity, disturbance regime, and ecosystem size, as well as intrinsic factors including food web motifs. However, current theories have largely assumed simple, two-dimensional habitat architectures, and may not be adequate to predict food chain length in ecosystems which have a complex, branching structure. Here, we develop a spatially explicit theoretical model which provides an integrated framework for predicting food chain length in branching networks. We show food chain length responds independently to both ecosystem size and complexity, and that these responses are contingent upon other extrinsic and intrinsic controls. Our results show that accounting for ecosystem complexity is an important driver of food chain length and may reconcile inconsistent results from empirical studies of food chain length in river ecosystems.

About naturalization of Berberis aquifolium in the territory of Nature Reserves of the Southern Coast of the Crimea

At the present stage of development of the economies of different states, the problem of biological invasions is considered one of the top-priorities. A special place among the different areas of research of biological invasions is occupied by the study of the most aggressive and dangerous alien plants in Protected Areas, as they pose a threat to the conservation of ecosystems and their biodiversity. The paper provides information on the phytocenotic diversity of communities with Berberis aquifolium Purch in native - in North America, as well as data on the distribution and degree of naturalization of the species in Eurasia, Australia, and New Zealand. It is established that Mahonia in many regions has the status of an invasive species, it is found both in anthropogenic disturbed and in natural communities, inhabiting a wide range of ecotopes (forest parks, meadows, forests, coastal dunes, etc.). On the Southern Coast of the Crimea, communities with Berberis aquifolium Purch were identified in forest park stands, as well as in coniferous and mixed forests, which belong to the classes Erico-Pinetea, Quercetea pubescentis according to the Braun-Blanquet classification. Preliminary data on the invasion of the species in the natural communities of two Protected Areas (PAs) - "Yalta Mountain Forest" and "Cape Martyan" are presented. The species is most widespread at altitudes from 200 to 400 m above sea level in pine, oak-hornbeam-pine and oak-pine forests belonging to the class Erico-Pinetea . In the lower forest belt at an altitude of up to 200 m above sea level, it is found in the pubescent oak-hornbeam and ash-oak-dogwood communities with Juniperus excelsa , J. deltoides , and Pinus pallasianae , which are part of the class Quercetea pubescentis .

Community-Level Interactions and Disease Dynamics

An ecological community includes all individuals of all species that interact within a single patch or local area of habitat. Understanding the outcome of host–parasite interactions and predicting disease dynamics is particularly challenging at this biological scale because the different component species interact both directly and indirectly in complex ways. Current shifts in biodiversity due to global change, and its associated modifications to biological communities, will alter these interactions, including the probability of disease emergence, its dynamics over time, and its community-level consequences. Birds are integral component species of almost all natural communities. Due to their ubiquity and specific life history traits, they are defining actors in the ecology, evolution, and epidemiology of parasitic species. To better understand this role, this chapter examines the relative importance of birds and parasites in natural communities, revisiting basic notions in community ecology. The impact of changes in diversity for disease dynamics, including the debate surrounding dilution and amplification effects are specifically addressed. By considering the intrinsic complexities of natural communities, the importance of combining data from host and parasite communities to better understand how natural systems function over time and space is highlighted. The different elements in each section of the chapter are illustrated with brief, concrete examples from avian species, with a detailed example from marine bird communities in which Lyme disease bacteria circulate.

Ecology and molecular targets of hypermutation in the global microbiome

Changes in the sequence of an organism’s genome, i.e., mutations, are the raw material of evolution. The frequency and location of mutations can be constrained by specific molecular mechanisms, such as diversity-generating retroelements (DGRs). DGRs have been characterized from cultivated bacteria and bacteriophages, and perform error-prone reverse transcription leading to mutations being introduced in specific target genes. DGR loci were also identified in several metagenomes, but the ecological roles and evolutionary drivers of these DGRs remain poorly understood. Here, we analyze a dataset of >30,000 DGRs from public metagenomes, establish six major lineages of DGRs including three primarily encoded by phages and seemingly used to diversify host attachment proteins, and demonstrate that DGRs are broadly active and responsible for >10% of all amino acid changes in some organisms. Overall, these results highlight the constraints under which DGRs evolve, and elucidate several distinct roles these elements play in natural communities.

The land snails of Lichadonisia islets (Greece)

The Lichadonisia island group is located between Maliakos and the North Evian Gulf, in central Greece. Lichadonisia is one of the few volcanic island groups of Greece, consisting mainly of lava flows. Today the islands are uninhabited with high numbers of visitors, but permanent population existed for many decades in the past. Herein, we present for the first time the land snail fauna of the islets and we compare their species richness with islands of similar size across the Aegean Sea. This group of small islands, provides a typical example on how human activities in the current geological era, i.e., the Anthropocene, alter the natural communities and differentiate biogeographical patterns.