Federico Maria Tardella

Assessment of interaction between sheep and poorly palatable grass: a key tool for grassland management and restoration

Invasion of poorly palatable grasses due to abandonment or improper grazing management decreases pastures feeding value and biodiversity. With the aim to control their spread, we assessed the relationship between sheep foraging behavior and changes in aboveground phytomass, leaf traits, and chemical features of the tall grass Brachypodium rupestre and evaluated the effects of a B. rupestre-based diet on epithelium keratinization of rumen. Our results demonstrated that sheep became less selective throughout the experimental trials and B. rupestre decreased its aboveground phytomass. Some leaf traits showed significant changes (LDMC, LA, and ADL were higher in ungrazed areas; leaf nitrogen content was higher in the grazed ones). In addition, we detected an increase of the degree of epithelium keratinization of sheep. Thus high grazing pressure can be used to control the spread of B. rupestre, but negative effects on animal welfare due to the increase of rumen keratinization might be expected.

Trait-related flowering patterns in submediterranean mountain meadows

The research aims were to identify the flowering pattern and the related functional strategies in submediterranean mountain meadows (central Italy) and understand their relationships with some environmental and community structure variables. The number of flowering shoots per species was counted and environmental data were collected in 40 plots during 2009. Analysis of the species and trait data sets highlighted a flowering pattern and an underlying functional pattern. Dominant species tend to bloom in the central phases of the growing season when no stress acts in the system and a long time is available for plant growth and seed maturation. This kind of species does not need functional strategies allowing the canopy fast pre-emption or the tolerance to drought stress. Non-dominant species have two groups of functional strategies that allow them to share the same flowering period of dominant ones by a different type of space occupation (spatial niche partitioning) or to flower before or after their flowering period (temporal niche partitioning). The functional strategies involved in the temporal niche partitioning have a dual ecological meaning, limiting competition with dominant species by fast growth and seed maturation (e.g., short stature, mobilisation of stored reserves, colonization of unexploited soil niches by clonal growth organs and light seeds) and enabling tolerance to drought stress (e.g., scleromorphic and succulent leaves, persistent green leaves, tap roots) and to the low light availability at the ground level owing to the change of grassland structure (e.g., tall size and upright growth form).

Evidence of Facilitation Cascade Processes as Drivers of Successional Patterns of Ecosystem Engineers at the Upper Altitudinal Limit of the Dry Puna

Facilitation processes constitute basic elements of vegetation dynamics in harsh systems. Recent studies in tropical alpine environments demonstrated how pioneer plant species defined as “ecosystem engineers” are capable of enhancing landscape-level richness by adding new species to the community through the modification of microhabitats, and also provided hints about the alternation of different ecosystem engineers over time. Nevertheless, most of the existing works analysed different ecosystem engineers separately, without considering the interaction of different ecosystem engineers. Focusing on the altitudinal limit of Peruvian Dry Puna vegetation, we hypothesized that positive interactions structure plant communities by facilitation cascades involving different ecosystem engineers, determining the evolution of the microhabitat patches in terms of abiotic resources and beneficiary species hosted. To analyze successional mechanisms, we used a “space-for-time” substitution to account for changes over time, and analyzed data on soil texture, composition, and temperature, facilitated species and their interaction with nurse species, and surface area of engineered patches by means of chemical analyses, indicator species analysis, and rarefaction curves. A successional process, resulting from the dynamic interaction of different ecosystem engineers, which determined a progressive amelioration of soil conditions (e.g. nitrogen and organic matter content, and temperature), was the main driver of species assemblage at the community scale, enhancing species richness. Cushion plants act as pioneers, by starting the successional processes that continue with shrubs and tussocks. Tussock grasses have sometimes been found to be capable of creating microhabitat patches independently. The dynamics of species assemblage seem to follow the nested assemblage mechanism, in which the first foundation species to colonize a habitat provides a novel substrate for colonization by other foundation species through a facilitation cascade process.

Effect of tall-grass invasion on the flowering-related functional pattern of submediterranean hay-meadows

Several studies demonstrated that abandonment changes the functional composition of grasslands; nevertheless, little is known about the effects of grassland abandonment on the flowering-related functional pattern. We hypothesized that invasion by tall grasses affects this pattern. We counted the number of flowering shoots per species at five times during the growing season, in 80 plots placed in mown and in abandoned grasslands (central Apennines), and assessed the differences in the trait composition of flowering species between the two treatments. The selected traits were linked to resource acquisition and stress tolerance strategies. Our results indicated that abiotic environmental control is prevalent in determining the phenological pattern in both conditions and in accordance with the phenological “mid-domain hypothesis”. We demonstrated that when the dominant species is a tall grass with competitive behaviour, the magnitude of this phenomenon is amplified due to the abiotic changes yielded by the tall grass invasion. Indeed, in the central and late phases of the growing season (when invasive tall grasses are growing and blooming), abandoned grasslands were marked by a set of traits devoted to stress tolerance or underlying a long reproductive cycle or linked to competition for light.

Context-dependent effects of abandonment vs. grazing on functional composition and diversity of sub-Mediterranean grasslands

Though the interplay of grazing intensity and the availability of resources is a key driver in grassland composition, very few studies focused on trait changes after abandonment along productivity gradients. Through a comparative approach, we aimed to assess the context-dependent effects of long-term grazing cessation on functional composition and diversity in sub-Mediterranean grasslands. We hypothesized that variability of topography, soil and vegetation structure on a fine scale drives the trait-based dynamics after long-term abandonment, also influencing the patterns of functional diversity. On a calcareous mountain ridge of central Italy, we collected data on species cover and traits, site characteristics, soil depth and vegetation structure in 0.5 m × 0.5 m plots located in extensively grazed pastures and in grasslands abandoned since the early 1970s. We analysed patterns of species and traits in relation to environmental variables and management type, and trends in functional diversity (FD, Rao’s quadratic entropy) along a productivity gradient. We found that grazing cessation reduced the overall FD and that the direction of species and trait response after long-term grazing cessation were affected, on a fine scale, by the soil depth / productivity gradient. In dryer conditions, species and functional responses were less affected by abandonment, and were devoted to resistance to both stress and disturbance. In abandoned pastures we detected a significant decrease in FD with increasing productivity, leading to a shift from functional strategies devoted to grazing avoidance and tolerance to those devoted to competition for light and resource acquisition. This trend was related to the filtering effect of coarse tall grasses, which spread in highly productive conditions. In grazed grasslands, we detected an overall increasing trend of FD with increasing productivity, confirming the key role of extensive grazing in maintaining high levels of FD.

Long-term cropland abandonment does not lead per se to the recovery of semi-natural herb communities deemed habitats of community interest

Abstract Anogramma leptophylla is one of the rarest fern species in Balkan Peninsula. In Croatia, several localities were noted prior to this study, when its presence was confirmed with a discovery of a small population on the island of Mljet (Southern Adriatic). This was, after almost 80 years, the first reliable finding of this species along Eastern Adriatic. The establishment of A. leptophylla on the western part of the island of Mljet may be attributable to certain favourable environmental conditions, but essentially to higher air and soil humidity. Its unusual bryophyte-like life strategy, with short-living annual sporophytes, facilitates its survival under Mediterranean climate, generally unfavourable for pteridophytes.

Evaluation of storage conditions on equine adipose tissue-derived multipotent mesenchymal stromal cells

The transplantation of multipotent mesenchymal stromal cells (MSCs) is a potentially promising therapy for the treatment of tendon and ligament injuries and some forms of articular pathology in horses. This study investigated the effects of storage conditions on MSCs. Equine adipose tissue-derived MSCs (eAd-MSCs) were stored at 4 °C and at room temperature (RT) for 24 and 48 h, and viability, doubling time, expression of CD44 and CD90 antigens, clonogenic/differentiation potentials, and karyotype were subsequently evaluated. The eAd-MSC viability was significantly affected by the storage conditions, while doubling time was not significantly altered. The findings indicate (1) that storage at 4 °C is preferable to RT as this results in greater numbers of viable, morphologically normal cells, and (2) that cells should be used within 24 h.

Map of changes in landscape naturalness in the Fiastra and Salino catchment basins (central Italy)

This work assessed the spatio-temporal variation of land use in the catchment basins of Fiastra and Salino (central Italy) and its effect on landscape naturalness over a 30-year period (1978–2008). The study area (centroid coordinates 43°7′29.44′′ N; 13°20′34.56′′E) was divided into ecologically homogeneous units (land units) in terms of substrate, bioclimatic belt, and aspect using a GIS-based hierarchical approach for landscape classification and mapping. Land units were characterized from a phytosociological viewpoint, and their naturalness evaluated using the Index of Landscape Conservation status. Comparison of current and past vegetation naturalness of land units was used to prepare the map of changes in landscape naturalness in the Fiastra and Salino catchment basins (central Italy) at a scale of 1:50,000. It was found that, while the change of naturalness in the whole study area was around zero, the pattern of distribution of this change was heterogeneous: naturalness increased in land units of high hilly and mountain belts, mostly because of the spread of woods, to the detriment of shrublands, pre-wooded communities, and grasslands, while the opposite trend was recorded in the alluvial plain and low hills, because of increasing urbanization and landscape homogenization caused by the transformation of grasslands, shrublands, pre-wooded communities, and tree-planted arable lands into arable lands. The hierarchical approach to landscape classification and mapping provided information that could have not been detected by mere calculation of indices. This kind of analysis offers a method for improved interpretation of landscape evolution, affording valuable input for predicting transformation of land use, and thus for formulating sound environmental policies and planning optimum ecosystem management strategies.

Effect of management modification on the coenological composition of the North Adriatic pastoral landscape (Ćićarija, Croatia)

Effect of Management Modification on the Coenological Composition of the North Adriatic Pastoral Landscape (Ćićarija, Croatia) The research aim was to assess the dynamics of the North Adriatic pastoral landscape (Ćićarija, Croatia) with regard to the coenological composition of grassland communities, and, more specifically, to: i) assess the current grassland mosaic from a coenological viewpoint; ii) assess the effects of management abandonment on grassland species composition, also taking into account, as a basis for comparison, data on pastoral communities collected in the past decades. To achieve the research aims, 73 phytosociological relevés were carried out; for each of them field data (altitude, aspect, slope, landform) and information on grassland management were collected. Multivariate analysis of phytosociological relevés led to the identification of four vegetation types (Danthonio-Scorzoneretum villosae, Carici humilis-Centaureetum rupestris, Brachypodium rupestre-dominated stands, and Anthoxantho-Brometum erecti), which were linked to landform and to grassland management. Comparison in terms of social behaviour type composition of the grassland communities surveyed in the present study with the ones surveyed in the past decades, highlighted that the current management (grassland abandonment, as well as low intensity grazing and not periodic mowing) is leading to a percentage loss of pasture and meadow characteristic species, in favour of successional and ruderal ones. Namen raziskave je bil ovrednotiti dinamiko severnojadranske pašniške krajine (Čićarija, Hrvaška) predvsem cenološke sestavo travniških združb. Posebej smo želeli ugotoviti: i) trenuten travniški mozaik s cenološkega vidika, ii) spremembe opuščanja gospodarjenja na vrstno sestavo travnikov s primerjavo podatkov o pašnikih, pridobljenih v preteklih desetletjih. Naredili smo 73 fitocenoloških popisov in za vsakega od njih smo pridobili podatke o višini, legi, nagibu, krajinski obliki in informacijo o gospodarjenju. Z multivariatnimi analizami smo ugotovili štiri vegetacijske tipe (Danthonio-Scorzoneretum villosae, Carici humilis-Centaureetum rupestris, združbo z dominantno vrsto Brachypodium rupestre in Anthoxantho-Brometum erecti), ki smo jih povezali s krajinsko obliko in načinom gospodarjenja. Primerjava sestave zgradbe travniških združb glede na sinsociološko pripadnost vrst med današnjimi in starejšimi popisi je pokazala, da trenuten način gospodarjenja (opuščanje gospodarjenja, nizka intenziteta paše in le občasna košnja) vodi v izgubo značilnih vrst pašnikov in travnikov na račun vrst razvitejših sukcesijskih stadijev in vrst ruderalnih rastišč.

Filtering effect of temporal niche fluctuation and amplitude of environmental variations on the trait-related flowering patterns: lesson from sub-Mediterranean grasslands

Timing of flowering is a critical component of community assembly, but how plant traits respond to heterogeneity of resources has been identified mostly through observations of spatial variations. Thus, we performed a trait-based phenological study in sub-Mediterranean grasslands to assess the importance of temporal variation of resources in the species assemblage processes. We found that early flowering species have traits allowing for slow resource acquisition and storage but rapid growth rate. Instead, mid- and late-flowering species exhibited sets of strategies devoted to minimizing water loss by evapotranspiration or aimed at maximizing the species’ competitive ability, thanks to slow growth rate and more efficient resource acquisition, conservation and use. Our findings were consistent with the fluctuation niche theory. We observed that the amplitude of the environmental fluctuations influences the type and number of strategies positively filtered by the system. In fact, in the most productive grasslands, we observed the highest number of indicator trait states reflecting strategies devoted to the storage of resources and competition for light. Results seem also indicate that temporal variation of resources plays a role in trait differentiation and richness within a plant community, filtering traits composition of grasslands in the same direction, as formerly proved for spatial heterogeneity of resources.