Climate warming is causing a shift in biological communities in favor of warm-affinity species (i.e., thermophilization). Species responses often lag behind climate warming, but the reasons for such ...lags remain largely unknown. Here, we analyzed multidecadal understory microclimate dynamics in European forests and show that thermophilization and the climatic lag in forest plant communities are primarily controlled by microclimate. Increasing tree canopy cover reduces warming rates inside forests, but loss of canopy cover leads to increased local heat that exacerbates the disequilibrium between community responses and climate change. Reciprocal effects between plants and microclimates are key to understanding the response of forest biodiversity and functioning to climate and land-use changes.
Biodiversity time series reveal global losses and accelerated redistributions of species, but no net loss in local species richness. To better understand how these patterns are linked, we quantify ...how individual species trajectories scale up to diversity changes using data from 68 vegetation resurvey studies of seminatural forests in Europe. Herb-layer species with small geographic ranges are being replaced by more widely distributed species, and our results suggest that this is due less to species abundances than to species nitrogen niches. Nitrogen deposition accelerates the extinctions of small-ranged, nitrogen-efficient plants and colonization by broadly distributed, nitrogen-demanding plants (including non-natives). Despite no net change in species richness at the spatial scale of a study site, the losses of small-ranged species reduce biome-scale (gamma) diversity. These results provide one mechanism to explain the directional replacement of small-ranged species within sites and thus explain patterns of biodiversity change across spatial scales.
In spite of the great popularity of Ellenberg's Indicator Values (EIVs) in plant ecology, animal ecologists seldom use EIVs to address ecological questions. In this study we used EIVs to test their ...potential usefulness for the prediction of suitable habitat for pre-diapause larvae of the endangered butterfly species Euphydryas aurinia. Nine transects crossing grasslands in SW Poland with abundant populations of E. aurinia were designed. We sampled 76 vegetation plots along the transects. In addition, the presence of the larval webs of E. aurinia in sampled plots was also recorded. We then calculated the mean community EIVs of light, nitrogen, soil reaction, moisture and temperature for each sample plots. Generalized linear mixed-effects models (GLMMs) were used to assess which factors determine the local occurrence of larval webs of E. aurinia. We found the larval webs only in 12 plots, while the host plant was present in 39 of the examined plots. The presence of the host plant was the most important predictor in both models including all plots or including only plots with host plants. The other significant predictor was the mean EIV of light, and its importance increased in models considering all plots. We attributed the importance of the EIV of light to the site openness and density of the vegetation layer. A positive relationship between this predictor and the presence of larval webs indicates that sites with looser vegetation, a lower contribution of shrubs and tall herbs and better penetration of photosynthetically active radiation to lower vegetation layers are preferred by E. aurinia for oviposition. Moreover, the significance of EIV of light may be linked with management practices. Many light-demanding species decline after cessation of mowing as a result of litter accumulation and the dominance of tall herbs. An absence of light-demanding species decreases the community's mean EIV of light and thus indicates the influence of meadow abandonment.
It is generally hypothesized that forest dieback is a characteristic of alder swamp forests (alder carrs, Alnion glutinosae alliance). Different internal and external factors may trigger this ...process, including human disturbance, changes in river discharge, unusually severe and prolonged flooding, terminal age of an even-aged alder forest (ca. 100–150 years) and others. Although forest dieback in this type of forest may cause major changes in environmental conditions, the influence of this change on the floristic composition has not been well recognized. The study aimed to detect any possible changes in floristic variation in alder swamp forest following forest dieback. Vegetation plots in alder swamp forests affected by forest dieback were resurveyed 20 years after a previous study. PERMANOVA was used to test the significance of the compositional change and nonmetric multidimensional scaling (NMDS) with passively fitted means of the Ellenberg’s Indicator Values were used to interpret its ecological meaning. In addition, different structural and diversity indices were compared, including species richness, percentage cover of vegetation layers, Shannon and Simpson diversity and evenness. Finally, we analyzed changes in the frequency of vascular plant species using Chi square tests. We recorded clear and significant compositional changes following alder swamp forest dieback. This change was most related to the gradient of moisture, followed by the gradients of light and temperature. The analysis of the individual species showed that the species of hummocks declined, while the species of hollows increased. Moreover, the current communities are dominated by some hydrophytes that were not recorded 20 years ago. Forest dieback resulted in profound changes in the hydrological regime. The observed changes are consistent with a model of cyclic succession as proposed for alder swamps. In addition, we conclude that the natural forest dynamics have to be taken into consideration while interpreting the results of re-survey studies.
Transposable elements, identified in all eukaryotes, are mobile genetic units that can change their genomic position. Transposons usually employ an excision and reintegration mechanism, by which they ...change position, but not copy number. In contrast, retrotransposons amplify via RNA intermediates, increasing their genomic copy number. Hence, they represent a particular threat to the structural and informational integrity of the invaded genome. The social amoeba
, model organism of the evolutionary Amoebozoa supergroup, features a haploid, gene-dense genome that offers limited space for damage-free transposition. Several of its contemporary retrotransposons display intrinsic integration preferences, for example by inserting next to transfer RNA genes or other retroelements. Likely, any retrotransposons that invaded the genome of the amoeba in a non-directed manner were lost during evolution, as this would result in decreased fitness of the organism. Thus, the positional preference of the
retroelements might represent a domestication of the selfish elements. Likewise, the reduced danger of such domesticated transposable elements led to their accumulation, and they represent about 10% of the current genome of
. To prevent the uncontrolled spreading of retrotransposons, the amoeba employs control mechanisms including RNA interference and heterochromatization. Here, we review TRE5-A, DIRS-1 and Skipper-1, as representatives of the three retrotransposon classes in
, which make up 5.7% of the
genome. We compile open questions with respect to their mobility and cellular regulation, and suggest strategies, how these questions might be addressed experimentally.
The first reliable information on the occurrence of Rhododendron ferrugineum in the Karkonosze Mts (excluding spots of directly acknowledged anthropogenic origin) was provided by A. Boratynski in ...1983, but the status and origin of the plants were unknown. A recent phylogeographical study proved the natural character and relict status of the aforementioned population, which makes it the northernmost and most isolated site within the whole distribution of the species. In this study, we characterized the basic aspects of the ecology and conservation status of the population and, more specifically, focused on assessing the size of the population, general health of individuals, generative propagation ability, habitat conditions, and potential threats for the species. The population persists in the Sowia Dolina (east part of the Karkonosze Mts), in a microtopographically controlled, treeless microrefugium. Shrubs of R. ferrugineum are part of an acidophilous dwarf-heath plant community, similar to those occurring in the Alps and the Pyrenees, although less species-diverse. The plant community in the Karkonosze Mts has been preliminarily classified into the Genisto pilosae-Vaccinion alliance. The R. ferrugineum population consists of 68 individuals: 57 fully grown and juvenile and 11 seedlings. In 2017, 10 individuals flowered, seven of which developed fruits, while in 2018, 15 individuals produced flowers and eight developed mature fruits. Seeds collected in 2017 germinated in high numbers. Plants in the Karkonosze population hosted some fungal parasites typically found in Rhododendron species, but no intense disease symptoms strongly influencing plant fitness were observed. A combination of significant isolation, genetic distinctness, and high genetic diversity implies a high conservation priority for the R. ferrugineum population in Karkonosze. Despite the theoretical threats, including stochastic risks, the R. ferrugineum population seems to have been stable for a long time and, importantly, it is composed of individuals of different ages, from large flowering plants to seedlings. Keywords Karkonosze; glacial relict; population characteristic; refugium; Sudetes
We report here the first wild locality of Exobasidium rhododendri (Fuckel) C. E. Cramer in Poland. This peculiar species is an obligatory pathogenic basidiomycete, which induces formation of galls on ...leaves of Rhododendron. It was found for the first time in Poland in 2017 on Rhododendron ferrugineum L. plants in a population of this shrub in the Karkonosze Mts (the Sudetes range). The species was recently shown to be native and a relict. We also present a basic description of the species based on the specimens from the abovementioned locality. Keywords Basidiomycota; distribution; fungal pathogens; Rhododendron ferrugineum
The Dictyostelium Intermediate Repeat Sequence 1 (DIRS-1) is the name-giving member of the DIRS order of tyrosine recombinase retrotransposons. In Dictyostelium discoideum, DIRS-1 is highly amplified ...and enriched in heterochromatic centromers of the D. discoideum genome. We show here that DIRS-1 it tightly controlled by the D. discoideum RNA interference machinery and is only mobilized in mutants lacking either the RNA dependent RNA polymerase RrpC or the Argonaute protein AgnA. DIRS retrotransposons contain an internal complementary region (ICR) that is thought to be required to reconstitute a full-length element from incomplete RNA transcripts. Using different versions of D. discoideum DIRS-1 equipped with retrotransposition marker genes, we show experimentally that the ICR is in fact essential to complete retrotransposition. We further show that DIRS-1 produces a mixture of single-stranded, mostly linear extrachromosomal cDNA intermediates. If this cDNA is isolated and transformed into D. discoideum cells, it can be used by DIRS-1 proteins to complete productive retrotransposition. This work provides the first experimental evidence to propose a general retrotransposition mechanism of the class of DIRS like tyrosine recombinase retrotransposons.
Aim
To assess the origin and genetic relationship of the northernmost population of Rhododendron ferrugineum in the Karkonosze Mts. (the Sudetes), located 350 km north of the previously acknowledged ...species limit, in the context of the whole species range; to discuss, based on this case study, the glacial history of the Central European mountain flora and importance of rare, relict populations for biogeographical inference and diversity conservation.
Location
European mountains: Sudetes, Alps, Pyrenees.
Methods
We sampled 90 individuals from 26 R. ferrugineum populations spanning the whole species’ range. To infer genetic structure, diversity and relationships among populations and isolated parts of the geographical range, we applied genome‐wide amplified fragment length polymorphism (AFLP) genotyping and sequencing of four cpDNA fragments and nrDNA ITS region.
Results
Our AFLP analysis revealed four distinct genetic groups in R. ferrugineum, one formed by the northernmost population from (a) the Karkonosze Mts. (the Sudetes) and the other three comprising populations from the (b) Western Alps and Pyrenees, (c) South‐Westernmost Alps and (d) Eastern Alps. Genetic isolation of the Karkonosze population was further corroborated by a repetitive pattern differentiation in plastid DNA sequences, otherwise almost monomorphic across the range. Population from the Karkonosze was most closely related to those from the Western Alps and not from the geographically closest Eastern Alps.
Main conclusions
We show that the population of R. ferrugineum in the Karkonosze Mts. is a glacial relict and not a recently established or introduced population. Its distinctiveness and high genetic diversity show that it represents a northern, previously undetected, genetic lineage of the species in Europe, which persisted through climatic changes in a small but stable microrefugium. Our case study highlights the importance of an adequate coverage of a species’ range in phylogeographical studies and the significance of peripheral parts of the range to reveal biogeographical history of lineages. It also supports the Karkonosze Mountains as an important refugium for the Central European mountain flora.
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