Mountain areas are particularly sensitive to climate change. Species distribution models predict important extinctions in these areas whose magnitude will depend on a number of different factors. ...Here we examine the possible impact of climate change on the Rhododendron ferrugineum (alpenrose) niche in Andorra (Pyrenees). This species currently occupies 14.6 km2 of this country and relies on the protection afforded by snow cover in winter. We used high-resolution climatic data, potential snow accumulation and a combined forecasting method to obtain the realized niche model of this species. Subsequently, we used data from the high-resolution Scampei project climate change projection for the A2, A1B and B1 scenarios to model its future realized niche model. The modelization performed well when predicting the species's distribution, which improved when we considered the potential snow accumulation, the most important variable influencing its distribution. We thus obtained a potential extent of about 70.7 km(2) or 15.1% of the country. We observed an elevation lag distribution between the current and potential distribution of the species, probably due to its slow colonization rate and the small-scale survey of seedlings. Under the three climatic scenarios, the realized niche model of the species will be reduced by 37.9-70.1 km(2) by the end of the century and it will become confined to what are today screes and rocky hillside habitats. The particular effects of climate change on seedling establishment, as well as on the species' plasticity and sensitivity in the event of a reduction of the snow cover, could worsen these predictions.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Mountain areas boast high levels of biodiversity due to the wide variety in topography, climates and traditional land-use practices they embrace. Recent changes in the mountain agro-ecosystems of ...Europe have led to a decline in these traditional practices (above all grazing) and have had negative effects on biodiversity. In this study we evaluated the effects of grazing pressure on plant species diversity and also focused on the common and rare species diversity, forage quality and forage production in the Festuca airoides, Festuca eskia, Festuca gautieri, Festuca paniculata and Nardus stricta grassland communities. These analyses could be of great importance in identifying the pastoral management practices that are most consistent with the conservation of plant diversity in the Andorran subalpine and alpine grasslands. Data were collected at 113 sampling sites exposed to either high or low grazing pressures. In all, 222 vegetation line-transects were established from which samples were collected and analysed using the NIRS method. In addition the lignin, protein and fibre fractions were obtained in order to evaluate the quality of the forage. In the Andorran summer pastures, the Festuca gautieri calcareous grasslands had the greatest plant species diversity, while the Festuca eskia, Festuca airoides and Nardus stricta grasslands had the lowest plant species diversity and a lack of common species due to their less homogeneous spatial structure. The highest quality forage corresponds to the Festuca gautieri and Nardus stricta grasslands, while the Festuca eskia grasslands have the lowest quality forage. Although high grazing pressure can lead to greater species diversity, it also tends to diminish forage quality and/or energy content by increasing the lignin content. Thus, domestic livestock is a fundamental element in these grasslands and an increase in the grazing pressure of the different types of livestock (cattle, sheep and horses) is necessary since a more balanced distribution of grazers between the grassland types – rather than an increase in grazers – will not be sufficient to maintain plant biodiversity. Likewise, there is a need to re-establish the practice of transhumance, a traditional pastoral practice based on the movement of livestock between winter lowland pastures and upland summer pastures.
Species diversity may be underestimated even in well-explored mountain regions due to the lack of in-depth research in taxonomically intricate groups. Filling such knowledge gap is necessary to ...optimize conservation management, specially for species occurring in vulnerable ecosystems such as Southern European mountains.
Campanula
sect.
Heterophylla
is a complex group with a high proportion of endemic taxa in European mountain ranges, and whose species delineation is often controversial due to extensive morphological variation. We investigated the phylogenetic relationships and evolutionary entity of its taxa occurring in the Pyrenees, with a special focus on the Pyrenean endemic
C. jaubertiana
(which is sometimes included as a subspecies of or merged with
C. cochleariifolia
); and
C. andorrana
, a taxon allegedly endemic to Andorra (Eastern Pyrenees) and of uncertain taxonomic value. We obtained chloroplast genome and nuclear ribosomal DNA sequences, including several individuals of the three focus taxa, and conducted morphometric analyses. Phylogenetic analyses show that
C. jaubertiana
sensu lato (s. l.; i.e. including
C. andorrana
) constitutes a clearly distinct lineage that is not even closely related to
C. cochleariifolia
; consistent differences in floral morphology were detected between them. Our results support two main evolutionary lineages within
C. jaubertiana
s. l., one corresponding to populations in Central Pyrenees, and another one in Eastern Pyrenees plus Catalan Pre-Pyrenees. Given the degree of genetic and morphological differentiation, we propose the species rank for each lineage (
C. jaubertiana
and
C. andorrana,
respectively) and provide a taxonomic treatment. These two Pyrenean endemics likely diverged through transverse allopatric speciation.
Safeguarding Earth's tree diversity is a conservation priority due to the importance of trees for biodiversity and ecosystem functions and services such as carbon sequestration. Here, we improve the ...foundation for effective conservation of global tree diversity by analyzing a recently developed database of tree species covering 46,752 species. We quantify range protection and anthropogenic pressures for each species and develop conservation priorities across taxonomic, phylogenetic, and functional diversity dimensions. We also assess the effectiveness of several influential proposed conservation prioritization frameworks to protect the top 17% and top 50% of tree priority areas. We find that an average of 50.2% of a tree species' range occurs in 110-km grid cells without any protected areas (PAs), with 6,377 small-range tree species fully unprotected, and that 83% of tree species experience nonnegligible human pressure across their range on average. Protecting high-priority areas for the top 17% and 50% priority thresholds would increase the average protected proportion of each tree species' range to 65.5% and 82.6%, respectively, leaving many fewer species (2,151 and 2,010) completely unprotected. The priority areas identified for trees match well to the Global 200 Ecoregions framework, revealing that priority areas for trees would in large part also optimize protection for terrestrial biodiversity overall. Based on range estimates for >46,000 tree species, our findings show that a large proportion of tree species receive limited protection by current PAs and are under substantial human pressure. Improved protection of biodiversity overall would also strongly benefit global tree diversity.
The impact of ongoing climate change on plant communities varies according to vegetation type and location across the globe. Snowbed flora count among the most sensitive vegetation due to their ...dependence on long-lasting snow patches. This is especially the case toward their rear distribution edge, where warming has already induced a marked decrease in snow deposition. Thus, analysing the dynamics of snowbed plant communities is crucial for understanding the ecological processes that condition their persistence under new environmental conditions. The Pyrenees represent the southern distribution limit of several eurosiberian snowbed species. We surveyed eight snowbeds based on permanent plots, where the presence of each taxon was recorded annually between 2012 and 2019. We analysed vegetation patterns between sites and plots, related them to environmental gradients, and assessed temporal trends of community dynamics. We detected important between-site differences regarding species composition. However, these differences were not supported by species' biogeographical patterns, which suggests that local abiotic factors filter species with distinct autecology. In parallel, temporal community turnover was observed through the expansion of widespread grassland species, which supports the hypothesis of colonisation of snowbeds by common alpine taxa. Such changes could be related to a decrease in snow cover over recent times, which releases extreme environmental constraints to plant growth. Therefore, it is crucial to characterise fine-scale ecological conditions to forecast plant community dynamics and provide reliable information for conserving snowbed vegetation across the Palearctic.
Parasitism is a key factor in the population dynamics of many herbivorous insects, although its impact on host populations varies widely, for instance, along latitudinal and altitudinal gradients. ...Understanding the sources of geographical variation in host–parasitoid interactions is crucial for reliably predicting the future success of the interacting species under a context of global change.
Here, we examine larval parasitism in the butterfly Aglais urticae in south‐west Europe, where it is a mountain specialist. Larval nests were sampled over 2 years along altitudinal gradients in three Iberian mountain ranges, including the Sierra Nevada, home to its southernmost European population. Additional data on nettle condition and adult butterflies were obtained in the study areas.
These data sources were used to investigate whether or not differences in parasitism rates are related to the geographical position and phenology of the host, and to the availability of the host plants.
Phenological differences in the host populations between regions were related to the severity of summer drought and the corresponding differences in host plant availability. At the trailing‐edge of its distribution, the butterfly's breeding season was restricted to the end of winter and spring, while in its northern Iberian range the season was prolonged until mid‐summer. Although parasitism was an important source of mortality in all regions, parasitism rates and parasitoid richness were highest in the north and lowest in the south. Moreover, within a region, there was a notable increase in parasitism rates over time, which probably led to selection against an additional late summer host generation in northern regions. Conversely, the shorter breeding season in Sierra Nevada resulted in a loss of synchrony between the host and one important late season parasitoid, Sturmia bella, which may partly explain the high density of this butterfly species at the trailing‐edge of its range.
Our results support the key role of host phenology in accounting for differences in parasitism rates between populations. They also provide insights into how climate through host plant availability affects host phenology and, ultimately, the impact of parasitism on host populations.
Experienced parasitoid taxonomists, together with butterfly ecologists characterize the parasitoid assemblages associated with the iconic Aglais urticae along a latitudinal gradient. They find that parasitism is a major source of mortality and provide insights into how different environmental conditions translate into differences in the impact of parasitism.
Fundamental axes of variation in plant traits result from trade-offs between costs and benefits of resource-use strategies at the leaf scale. However, it is unclear whether similar trade-offs ...propagate to the ecosystem level. Here, we test whether trait correlation patterns predicted by three well-known leaf- and plant-level coordination theories - the leaf economics spectrum, the global spectrum of plant form and function, and the least-cost hypothesis - are also observed between community mean traits and ecosystem processes. We combined ecosystem functional properties from FLUXNET sites, vegetation properties, and community mean plant traits into three corresponding principal component analyses. We find that the leaf economics spectrum (90 sites), the global spectrum of plant form and function (89 sites), and the least-cost hypothesis (82 sites) all propagate at the ecosystem level. However, we also find evidence of additional scale-emergent properties. Evaluating the coordination of ecosystem functional properties may aid the development of more realistic global dynamic vegetation models with critical empirical data, reducing the uncertainty of climate change projections.
QUESTIONS: Humans are altering land use and impacting grazing intensities worldwide in alpine and sub‐alpine grasslands, and functional diversity (FD) is a useful tool for predicting changes in these ...grassland communities and for improving biodiversity conservation. We asked: (1) how does functional richness (FRic) differ between the five predominant grassland types in Andorra (2) of these five grassland types, which plant communities are subject to high habitat filtering and which are driven primarily by competitive interactions; (3) are certain grassland communities more prone to degradation than others; and (4) how do grazing intensity and elevation influence variations in FD indices? LOCATIONS: Five types of sub‐alpine and alpine grassland communities dominated by Festuca airoides, F. eskia, F. gautieri, F. paniculata and Nardus stricta in Andorra, at various elevations and with differing grazing intensities within a grassland type. METHODS: We used multiple functional diversity indices and structural equation modelling (SEM) to determine how grazing intensity, elevation, species richness and productivity affect functional diversity in 222 vegetation transects. RESULTS: Both plant diversity and functional richness were higher at higher grazing intensities, with the highest values found in the F. gautieri and F. paniculata grasslands and lowest in the Nardus stricta, F. airoides and F. eskia grasslands. Habitat filtering was observed in F. airoides grasslands. There was a general tendency for higher competitive interactions among plants at higher elevations and/or when species diversity increased. None of the five grassland communities considered appears disturbed, and all present similar functional attributes between dominant species. CONCLUSIONS: Our results highlight the fact that grazing is an integral part of Andorran mountain grasslands, acting as a structural component and providing higher functional richness in the most grazed communities.
Aims: Sub-alpine grassland ecosystems have some of the highest biodiversity in Europe and constitute high-value natural resources. These grasslands are under threat because of the abandonment of ...traditional agro-pastoral activities and subsequent invasion by woody species. In the Central Pyrenees (Spain) several management techniques have been used to stop expansion of the highly encroaching shrub Echinospartum horridum. However, the ways in which these techniques affect recovery of sub-alpine grasslands are poorly understood. The final goal of this study is to gain information about the effects of E. horridum management practices and provide recommendations for the local stakeholders. Methods: This study evaluated the efficacy of controlled fires and mechanical removal of above-ground vegetation in controlling expansion of E. horridum into sub-alpine grasslands in the Central Pyrenees. E. horridum demography (germination and survival), soil seed bank and soil properties were recorded in two E. horridum stands where vegetation was previously removed by (1) fire (burning treatment) or (2) mechanical removal (cutting treatment) and (3) an undisturbed E. horridum stand (control). Results: The burning treatment increased germination and survival of E. horridum seedlings more than the cutting treatment, relative to the control. Therefore, cutting appeared to be a better option for controlling E. horridum. Soil seed density was higher in the management treatments than in the control, but it did not harbour sub-alpine grasslands species. E. horridum removal favoured recharge of the soil with seeds that arrived by dispersal. The soil seed bank in the burning treatment had higher seed abundance and seed diversity than in the cutting treatment; however, fire promoted a loss of soil nutrients. Conclusions: The soil seed bank composition (low abundance and diversity of native species) coupled with rapid regeneration rate of E. horridum would prevent recovery of the sub-alpine grassland based on the soil seed bank alone. Traditional shepherding has been reported to favour seed dispersal, and here we recommend E. horridum removal with cutting treatment as an additional practice for integrated management and recovery of the sub-alpine grasslands.
Abstract Questions Humans are altering land use and impacting grazing intensities worldwide in alpine and sub‐alpine grasslands, and functional diversity ( FD ) is a useful tool for predicting ...changes in these grassland communities and for improving biodiversity conservation. We asked: (1) how does functional richness ( FR ic) differ between the five predominant grassland types in Andorra (2) of these five grassland types, which plant communities are subject to high habitat filtering and which are driven primarily by competitive interactions; (3) are certain grassland communities more prone to degradation than others; and (4) how do grazing intensity and elevation influence variations in FD indices? Locations Five types of sub‐alpine and alpine grassland communities dominated by F estuca airoides , F . eskia , F . gautieri , F . paniculata and N ardus stricta in Andorra, at various elevations and with differing grazing intensities within a grassland type. Methods We used multiple functional diversity indices and structural equation modelling ( SEM ) to determine how grazing intensity, elevation, species richness and productivity affect functional diversity in 222 vegetation transects. Results Both plant diversity and functional richness were higher at higher grazing intensities, with the highest values found in the F . gautieri and F . paniculata grasslands and lowest in the N ardus stricta , F . airoides and F . eskia grasslands. Habitat filtering was observed in F . airoides grasslands. There was a general tendency for higher competitive interactions among plants at higher elevations and/or when species diversity increased. None of the five grassland communities considered appears disturbed, and all present similar functional attributes between dominant species. Conclusions Our results highlight the fact that grazing is an integral part of Andorran mountain grasslands, acting as a structural component and providing higher functional richness in the most grazed communities.
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