An Asphodelus ramosus dominated plant community in Montenegro

Our phytosociological study in Montenegro (Ćemovsko polje) deals with the syntaxonomy of arid grasslands in the Adriatic region and, in particular, different interpretations of plant communities dominated by Asphodelus ramosus. The main aims of this study were to contribute to knowledge of the composition of dry grasslands dominated by Asphodelus ramosus in Montenegro and to compare instances of Asphodelus ramosus dominated vegetation along the Adriatic. Our vegetation dataset included 82 phytosociological relevés: 17 from our recent field work and 72 relevés of South European Asphodelus ramosus communities. Ordination analysis (NMDS) was used for comparison of Asphodelus ramosus dominated communities in the Adriatic region. The Asphodelus ramosus community from Montenegro was classified into Bromo erecti-Chrysopogonetum grylli. The analysis revealed two distinct vegetation groups: grassland communities of the vegetation class Festuco-Brometea from Montenegro, Croatia and Albania, and edge vegetation of the new class Charybdido pancratii-Asphodeletea ramosi from Italy. Comparison with similar vegetation types shows high similarity with associations on the eastern Adriatic coast, where they are treated as grassland communities belonging to the alliance Chrysopogono grylli-Koelerion splendentis, order Scorzoneretalia villosae, class Festuco-Brometea.

Monitoring Climate Impacts on Annual Forage Production across U.S. Semi-Arid Grasslands

The ecosystem performance approach, used in a previously published case study focusing on the Nebraska Sandhills, proved to minimize impacts of non-climatic factors (e.g., overgrazing, fire, pests) on the remotely-sensed signal of seasonal vegetation greenness resulting in a better attribution of its changes to climate variability. The current study validates the applicability of this approach for assessment of seasonal and interannual climate impacts on forage production in the western United States semi-arid grasslands. Using a piecewise regression tree model, we developed the Expected Ecosystem Performance (EEP), a proxy for annual forage production that reflects climatic influences while minimizing impacts of management and disturbances. The EEP model establishes relations between seasonal climate, site-specific growth potential, and long-term growth variability to capture changes in the growing season greenness measured via a time-integrated Normalized Difference Vegetation Index (NDVI) observed using a Moderate Resolution Imaging Spectroradiometer (MODIS). The resulting 19 years of EEP were converted to expected biomass (EB, kg ha−1 year−1) using a newly-developed relation with the Soil Survey Geographic Database range production data (R2 = 0.7). Results were compared to ground-observed biomass datasets collected by the U.S. Department of Agriculture and University of Nebraska-Lincoln (R2 = 0.67). This study illustrated that this approach is transferable to other semi-arid and arid grasslands and can be used for creating timely, post-season forage production assessments. When combined with seasonal climate predictions, it can provide within-season estimates of annual forage production that can serve as a basis for more informed adaptive decision making by livestock producers and land managers.

Contribution of Awns to Seed Yield and Seed Shattering in Siberian Wildrye Grown under Irrigated and Rainfed Environments

The seed yield of grass species is greatly dependent on inflorescence morphological traits, starting with spikelets per inflorescence and seeds per spikelet, to kernel size, and then to awns. Previous studies have attempted to estimate the contribution of these traits on the harvested yield of major cereal crops, but little information can be accessed on the influence of awns on seed yield of forage grass species. Siberian wildrye (Elymus sibiricus L.) is a widely important perennial forage grass used to increase forage production in arid and semi-arid grasslands. The grass has long inflorescences with long awns developed at the tip end of the lemmas in the florets. In order to evaluate the effect of awns on Siberian wildrye seed production, awn excision analyses from 10 accessions were performed at flowering stage under irrigated and rainfed regimes. Overall, awn excision reduced thousand-seed weight and seed size under both irrigated and rainfed regimes, which decreased final seed yield per plant. De-awned plants produced significantly more seeds per inflorescence, but spikelets per inflorescence was not influenced by awn excision in either condition. Moreover, histological analyses showed a high degradation of the abscission layer in the awned plants than de-awned ones, and awn excision evidently improved average seed breaking tensile strength (BTS), and thus decreased the degree of seed shattering. In conclusion, the observed significant impact of awn excision on different yield-related traits mirrored the impact of awns on the performance of Siberian wildrye under diverse growing conditions. These results provide useful information for plant breeders, seed producers, and researchers to efficiently improve seed production in Siberian wildrye.

Climatic and Biological Factors Related with Goat Grazing Management in the Arid Grassland of the Coquimbo Region (Northern Chile)

(1) Background: Desertification is one of the most important environmental impacts around the world. In the semiarid grassland of North of Chile, overgrazing has deep effects on arid lands and consequently on its economy and social development. It is necessary to conduct very detailed studies to determine how the climate, the botanical composition and the grazing system affects this process; (2) Methods: In this paper, we have determined the effect on arid grasslands of three goat managements: exclusions, continuous and deferred grazing on forage biomass, richness, Berger–Parker’s dominance and Shannon’s diversity. This study was developed in Las Cardas Range Station (CEALC) of the University of Chile in the Coquimbo region. The effect of annual and seasonal rainfall on biomass, diversity, richness and dominance parameters was determined; (3) Results: Allochthonous, endemic and native species showed significant changes both for seasonal and annual precipitation. In contrast, the grazing system only affected dominance and biomass of native and endemic species. Deferred grazing was the only management system that increased overall biomass productivity, especially on the best forage plant species. Exclusions showed a positive influence on more endangered species, which were the most vulnerable to goat overgrazing; (4) Conclusions: In consequence, we proposed a network of areas under deferred grazing combined with exclusions. This strategy can increase simultaneously forage productivity, grassland conservation and preservation of associated resources as hunting and wildlife tourism. Moreover, this strategy of range management will allow the sustainability of community of farmers in one of the poorest and most desertified areas in South America.

Increasing aridity may reduce productivity and soil organic carbon storage with woody plant encroachment

Aims We have found a positive effect of woody plants on total plant carbon (C) storage in less arid grassland was shifted to a negative effect in arid grasslands in Xinjiang, a typical arid region in China. In this study, we further assessed the effects of woody plants on aboveground primary productivity (ANPP) and soil organic C (SOC) storage and explored the mediation of climate conditions on these effects. We also aimed to elucidate the reasons for the effects on SOC storage in terms of ANPP and belowground biomass C (BGC). Methods We compared the difference in ANPP and SOC content between pure and wooded grasslands and evaluated the relation between SOC content and ANPP and BGC in six grassland types along the altitude (climatic) gradients. Results In three arid types, woody plants had a negative effect on ANPP due to their more negative impacts on herbaceous plants and lower ANPP. The negative effect on ANPP and BGC led to that on SOC storage in these types. In less arid types, there had a positive effect on ANPP because woody plants had weaker negative impacts on herbaceous plants and higher ANPP. A positive effect on ANPP combined with a neutral impact on BGC contributed to a positive effect on SOC storage in these types. Conclusions Woody plants had a negative effect on ANPP and SOC storage in most arid grasslands in Xinjiang. We predicted that increasing aridity may reduce ANPP and SOC storage with woody plant encroachment in the future.

Diversity-stability relationships in arid grasslands as a function of soil pH

Diversity-stability relationships in grasslands depend on the environment. Climate change and soil degradation potentially alter soil pH and community stability within grassland environments, although it remains unclear how soil acidity and alkalinity affect diversity-stability relationships. We conducted a three-year experiment of acidification and alkalization treatments in an arid grassland in northern China, and found that increasing and decreasing soil pH reduced community species richness, community diversity, community and dominant species asynchrony, and biomass stability. Soil acidification reduced community stability by reducing dominant species stability. Soil alkalization reduced community stability by reducing species asynchrony and dominant species stability. Acidification significantly enhanced the availabilities of soil NO3—N, P, and K, but did not affect the concentrations of soil total C, N, and P. By contrast, alkalization significantly reduced soil total C and N, but did not affect the availabilities of soil N, P, and K. Structural equation model analysis revealed that altered soil pH affected soil nutrients associated with species asynchrony and community stability, which indicated the importance of soil nutrients in driving community stability. Our results suggest that soil pH–mediated community stability is mainly driven by dominant species stability rather than diversity. This study provides novel insights indicating that arid grassland stability would be weakened under changing soil pH, subsequently leading to land degradation and reducing long‐term productivity and sustainability.