The extension of forest area is a globally accepted tool to offset CO2 emissions from deforestation and the combustion of fossil fuels. The common assumption is that in addition to the perceived ...climate benefits increasing forest area will also support biodiversity, thus making afforestation a “win-win scenario”. Based on the existing scientific evidences, we show that joined climate and biodiversity benefits are strongly context-dependent and that the outcome of afforestation is often highly questionable. In Europe, grasslands managed at low intensity contribute substantially to biodiversity conservation and carbon storage. However, many of these grasslands have been lost due to abandonment and subsequent spontaneous succession towards woody vegetation, or due to land use intensification. Moreover, grasslands are the ecosystems most often deliberately afforested in the context of EU carbon-centered policies that may thus counteract biodiversity conservation programmes. By reviewing the main EU policies targeting forests and grasslands, we found a striking ambivalence between policies and funding schemes addressing grassland conservation on the one hand (e.g. Habitats Directive, green payments within the Common Agricultural Policy) and those supporting afforestation on the other (e.g. rural development funds). We suggest three measures towards a better harmonization of the European Union policies that target forest and grassland ecosystems: (1) promoting the alignment of the decisions taken across different policy sectors; (2) focusing on the whole range of ecosystem services and biodiversity issues rather than on carbon management only; (3) valuing systems managed at low-intensity for their multifunctionality.
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•About 17% of EU grasslands have conservation value (sensu Habitats Directive)•An unfavourable conservation status is reported for about 80% of these grasslands•About 2000km2 of EU grasslands are lost annually, mostly those extensively managed•This loss is due to afforestation (30%) and to conversion to crops/urban sprawl (70%)•Afforestation cannot offset CO2 emissions and hampers biodiversity conservation
Questions: To what extent have semi-natural grassland plant species composition and functional traits changed during the past five decades? Which are the main directions of change? Which ...environmental, management and landscape factors have determined these changes? Location: Central and southern Apennines of Italy. Methods: In 2013-2014, we used a stratified random sampling design to revisit 132 semi-natural grasslands originally sampled between 1966 and 1992. The exact locations of the historical plots were not available but they were associated with detailed vegetation maps. Plots were divided in 17 groups based on study area and original community type. To assess changes in species composition we ran PERMANOVA and RDA. The extent of change was estimated by comparing each new plot with the quantitative species pool of the corresponding historical group; species composition changes were calculated using Bray-Curtis coefficient, and shifts in functional traits were quantified as differences in community-weighted means. These measures of change were used as response variables in mixed effects models including climate, topography, management and landscape metrics as explanatory variables. Results: The largest changes were related to successional dynamics, which occurred mainly in grasslands developing at low altitude and in the flattest sites where the soil organic horizon was relatively thick. Colonization by shrubs and trees was facilitated by high soil pH and amount of adjacent forests. Also, management factors affected the patterns of shifts in species composition and functional traits: grazing intensity was negatively related to the degree of compositional change as well as to the abundance of woody species, whereas the increase of species associated with frequent grazing disturbance was found at sites with higher values of soil salinity. Conclusions: Apennine semi-natural grasslands have undergone substantial changes in species composition and functional traits during recent decades. Compositional changes mainly indicated successional dynamics, likely following a decrease in grazing intensity, whereas some more accessible grasslands experienced an increase in disturbance-tolerant species. The combination of the re-visitation approach with functional traits allowed us to clarify different directions of changes in species composition, adding information on the ecological processes related to these changes.
Questions
Semi‐natural habitats are threatened by shifts in management with worrying effects on multiple facets of biodiversity. We revisited sites once representing a reference for a calcareous ...semi‐natural grassland habitat aiming to: (a) identify the drivers of taxonomic, functional and phylogenetic diversity, and habitat conservation state; (b) assess the role of characteristic and derived diversity in determining these patterns; and (c) discuss the possibility of reconciling the goals of habitat conservation and enhancement of different facets of plant diversity.
Location
Seven sites along the Apennines (Italy), from Mt. Catria (43.46206° N, 12.70397° E) to Mt. Alpi (40.11768° N, 15.98341° E).
Methods
For 132 revisited plots, we calculated vascular plant taxonomic, functional and phylogenetic diversity using Hill numbers, and used boosted regression trees to investigate their response to the compositional dissimilarity from historical plots, to grazing intensity and to environmental variables. We identified characteristic and derived diversity and summarized them in an index of habitat conservation state whose drivers were investigated using the same approach.
Results
Plant diversity was influenced by the site, whereas the habitat conservation state responded more markedly to vegetation type. Grazing intensity, slope and soil variables drove taxonomic and functional diversity, and the habitat conservation state, with some differences in their relative importance. Phylogenetic diversity responded only partly to grazing intensity, while it showed a major response to increasing temperatures.
Conclusions
Patterns and drivers of different facets of plant diversity partially differ from those of the habitat conservation state, suggesting that the management of semi‐natural habitats should be carefully tailored on specific conservation objectives. Generalized actions on grazing regimes and litter removal can promote habitat conservation, whereas the outcomes of these actions for plant diversity may differ across sites. Identifying areas particularly subjected to land‐use changes and/or climate warming may drive conservation actions.
By revisiting reference sites of calcareous semi‐natural grasslands, we found different patterns and drivers of plant diversity and habitat conservation state. Vegetation deviation from the habitat reference state, taxonomic and functional diversity mainly respond to grazing regimes, while phylogenetic diversity does to climate warming.
In Europe, the management of semi-natural grasslands is changing steadily in extent and intensity. These changes represent a serious threat to one of the most species-rich habitats in Europe; ...therefore, the related shifts in species composition should be assessed by means of sound scientific.
We describe a new methodology aimed at: (i) quantifying the temporal changes in vascular plant species composition of semi-natural grasslands; (ii) identifying the environmental and management variables that drive patterns of change. Our approach consists of a diachronic analysis based on historical phytosociological data associated with detailed vegetation maps. To describe and test our methodology, in 2013 we re-visited 24 historical plots of Bromus erectus grasslands that were first sampled in 1982. To designate the new sampling sites, we combined the topographic and typological information available for the historical plots with the spatial information of the associated map. The degree of change in species composition was calculated through ordination techniques; multivariate distances were used in a regression analysis to identify the environmental variables responsible for patterns of compositional change. Our worked example demonstrated that species composition has changed significantly in the last 30 years, with patterns that have been substantially influenced by topography and landscape structure.
Gospodarjenje s pol naravnimi travišči se v Evropi spreminja po obsegu in po intenzivnosti. Spremembe predstavljajo resno grožnjo enim vrstno najbolj bogatih habitatov v Evropi, zato je potrebno ocenjevati spremembe v vrstni sestavi z znanstveno metodo. Opisujemo novo metodologijo, ki stremi h (i) kvantifikaciji časovnih sprememb v vrstni sestavi pol naravnih travišč ter (ii) opredelitvi dejavnikov okolja in gospodarjenja, ki vodijo v spremembe. Naš pristop temelji na diakronični analizi historičnih fitocenoloških podatkov v povezavi z natančnimi vegetacijskimi kartami. Za opis in preverjanje metodologije smo leta 2013 ponovno obiskali 24 starejših ploskev travišč z vrsto Bromus erectus, mi smo jih prvič vzorčili leta 1982. Za izbiro novih vzorčnih mest smo kombinirali topografske in tipološke informacije, ki so na voljo za starejše ploskve, s prostorskimi informacijami na povezani karti. Stopnjo sprememb vrstne sestave smo izračunali z ordinacijskimi metodami; uporabili smo multivariatne razdalje v regresijski analizi za opredelitev okoljskih dejavnikov odgovornih za vzorec sprememb vrstne sestave. Z našim primerom smo pokazali, da se je vrstna sestava v zadnjih 30 letih značilno spremenila, na vzorec sprememb pa sta bistveno vplivala topografija in krajinska sestava.
Italy is among the European countries with the greatest plant diversity due to both a great environmental heterogeneity and a long history of man-environment interactions. Trait-based approaches to ...ecological studies have developed greatly over recent decades worldwide, although several issues concerning the relationships between plant functional traits and the environment still lack sufficient empirical evaluation. To draw insights on the association between plant functional traits and direct and indirect human and natural pressures on the environmental drivers, this article summarizes the existing knowledge on this topic by reviewing the results of studies performed in Italy adopting a functional trait approach on vascular plants, bryophytes and lichens. Although we recorded trait measurements for 1418 taxa, our review highlighted some major gaps in plant traits knowledge: Mediterranean ecosystems are poorly represented; traits related to belowground organs are still overlooked; traits measurements for bryophytes and lichens are lacking. Finally, intraspecific variation has been little studied at community level so far. We conclude by highlighting the need for approaches evaluating trait-environment relationship at large spatial and temporal scales and the need of a more effective contribution to online databases to tie more firmly Italian researchers to international scientific networks on plant traits.
The conservation of semi-natural habitats represents a primary challenge for European nature conservation due to their great species diversity and their vulnerability to ongoing massive land-use ...changes. As these changes rapidly transform and phase out semi-natural habitats, conservation measures should be prompt and specifically focused on a sound assessment of the degree of conservation. Here we develop a methodological strategy for the assessment of the degree of conservation of semi-natural grasslands based on well-defined criteria rather than on expert opinion. Through mixed effect models, we tested ten potential indicators, encompassing proxies of species composition, habitat structure, and landscape patterns, against a measure of compositional change from habitat favourable condition, i.e., an inverse proxy of conservation status. This measure derives from the re-visitation of 132 sampling units historically sampled between 1966 and 1992 along the Apennines. The compositional change was quantified as the dissimilarity between historical habitat species pools and the composition of current communities. The compositional change was significantly related to the number of habitat diagnostic species and the relative cover of woody species with opposite sign (positive and negative, respectively). We classified and combined the classes of these two indicators in each sampling unit to assess the habitat degree of conservation at the plot and at the Natura 2000 site level. At the plot level, our assessment was in good agreement with the occurrence of species of conservation concern. On the other hand, at the site level, our assessment was not always harmonic with the habitat conservation assessment officially reported for the site investigated.
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