Effects of grazing intensity on forage nutritive value of dominant grass species in Borana rangelands of Southern Ethiopia

Background Forage nutritive value analysis is an essential indicator of rangeland status regarding degradation and livestock nutrient demand. Thus, it is used to maintain healthy and sustainable rangelands that can provide the livestock with sufficient quantity and quality of forage. This study is conducted with the aim of investigating the effects of grazing intensity combined with seasonal variation on the nutritive values of dominant grass species in the Teltele rangeland. Methods The studied area is classified into no-grazed, moderately grazed, and overgrazed plots based on the estimated potential carrying capacity. Sampling data is collected during both rainy and dry seasons. The collected forage samples are analyzed for concentrations of crude protein (CP), acid detergent organic fiber (ADF), neutral detergent fiber (NDF), acid detergent lignin (ADL), ash, dry matter digestibility (DMD), potential dry matter intake (DMI), and relative feed/forage value (RFV). Results The results show significant (P < 0.05) effects of both grazing intensity and season to grazing intensity interactions on all forage nutrient content concentrations across all grass species both within and between treatments. The recorded CP concentrations of all grass species are high in the overgrazed site and low at the no-grazed site, while the fiber concentration is high in NG and low in OG. RFV data also varies greatly, with high value recorded in OG in the rainy season and low value found in NG mainly during the dry season. As a result, it is recommended that moderate grazing should be practiced on the study site to maintain the quality and quantity of forage and to manage it in a sustainable manner.

Inter-Annual Climate Differences Supersede Grazing Effects on the Anatomy and Physiology of a Dominant Grass Species.

Grassland ecosystems are historically shaped by climate, fire, and grazing as essential ecological drivers. These grassland drivers influence morphology and productivity via physiological processes, resulting in unique water and carbon use strategies among species and populations. Leaf-level physiological responses in plants are framed by the underlying microanatomy, previously shown to reflect patterns of carbon assimilation and water-use in leaf tissues. However, the magnitude to which microanatomy and physiology are impacted by grassland drivers, remains unstudied. To address this knowledge gap, we sampled from three locations along a latitudinal gradient in the mesic grassland region of the central Great Plains, USA during the 2018 and 2019 growing seasons. We measured annual biomass and forage quality at the plot level, while collecting physiological and microanatomical traits at the leaf-level in cattle grazed and ungrazed locations at each site. Leaf-level measurements were focused on the dominant grass species Andropogon gerardii (big bluestem) because of its high abundance, continental-scale distribution, and forage value. The two sampling seasons received markedly different levels of precipitation: drought conditions in 2018 and excessive early season precipitation in 2019. Ambient drought conditions negatively impacted A. gerardii physiology and drastically reduced productivity regardless of grazing. Leaf-level microanatomical traits, particularly those associated with water-use, varied within and across locations and between years. Our results highlight how trait plasticity can serve as an important tool for predicting future grassland responses to climate change and variable disturbances. Specifically, climate played a stronger role than grazing in shaping above-ground processes in microanatomy and physiology.

Syntaxonomical analysis of sandy grassland vegetation dominated by Festuca vaginata and F. pseudovaginata in the Pannonian basin

Festucetum vaginatae Rapaics ex Soó 1929 em. Borhidi 1996 is a characteristic association of the calcareous sandy areas of the Pannonian basin; its dominant grass species is Festuca vaginata. Another typical species of these sandy areas is the newly discovered F. pseudovaginata. The question is whether F. pseudovaginata forms an independent coenotaxa? Our study proved that F. vaginata and F. pseudovaginata populations grow separately and compose different associations. Stands dominated by F. pseudovaginata had a higher species richness and harboured twice as many Festuco-Brometea species compared to the Festucetum vaginatae stands. Diagnostic species of the Festucetum pseudovaginatae association are Festuca pseudovaginata, Colchicum arenarium, Ephedra distachya, Koeleria majoriflora, and Astragalus onobrychis. The number of species, the density of the individuals, and the variability and diversity of the vegetation separated it from the Festucetum vaginatae association; thus, it can be considered an independent endemic association. Festucetum pseudovaginatae has its own differentiating and dominant species: Carex stenophylla, Cynodon dactylon, Eryngium campestre, Kochia laniflora.

Do Sandy Grasslands along the Danube in the Carpathian Basin Preserve the Memory of Forest-Steppes?

Research highlights: In the present survey we examined the sandy grasslands appearing in the steppe-forest-steppe vegetation in the central part of the Carpathian Basin along the Danube. Background and objectives: We aimed to answer the following questions: Is it possible to build a picture of the past form of the vegetation through the examination of these vegetation units based on dominant grass taxa? Is Festuca wagneri an element of open grasslands or steppes? According to our hypothesis, these surveys can help reveal the original or secondary woody, shrubby patches through clarifying dominant taxa. Materials and Methods: We studied the grasslands in terms of coenology, putting great emphasis on the dominant Festuca taxa. Based on our preliminary surveys and literature, three vegetation types can be separated based on one single dominant Festuca taxon in each. The survey was conducted in four different locations in the Carpathian Basin. The cover of dominant grass species was used as an indicator value. The pedological background was also examined. Results: F. vaginata grassland is an open vegetation type based on its coenosystematic composition and ecological values. It grows in very weakly developed calcareous soil with sandy texture, with its lowest and highest organic carbon content ranging from 0.2% to 11.3% (0.2%), and the highest carbonate content (11.3%). Where the grasslands were disturbed, F. pseudovaginata and the recently discovered F. tomanii appeared. These taxa were also found in forest patches. The soil under F. pseudovaginata was more developed, in the surface horizon with higher organic carbon content (1.1%) and lower carbonate content (6.9%). The soil profile under F. wagneri developed the most, as the presence of deep and humus rich soil material from deflation and degradation showed. Conclusions: the dominant Festuca taxa of these vegetation types are good indicators of the changes in the vegetation and their ecological background.

Different responses of plant N and P resorption to overgrazing in three dominant species in a typical steppe of Inner Mongolia, China

Nutrient resorption from senesced leaves is an important mechanism for nutrient conservation in plants. However, little is known about the effect of grazing on plant nutrient resorption from senesced leaves, especially in semiarid ecosystems. Here, we evaluated the effects of grazing on N and P resorption in the three most dominant grass species in a typical steppe in northern China. We identified the key pathways of grazing-induced effects on N and P resorption efficiency. Grazing increased N and P concentrations in the green leaves of Leymus chinensis and Stipa grandis but not in Cleistogenes squarossa. Both L. chinensis and S. grandis exhibited an increasing trend of leaf N resorption, whereas C. squarrosa recorded a decline in both leaf N and P resorption efficiency under grazing. Structural equation models showed that grazing is the primary driver of the changes in N resorption efficiency of the three dominant grass species. For L. chinensis, the P concentration in green and senesced leaves increased the P resorption efficiency, whereas the senesced leaf P concentration played an important role in the P resorption efficiency of C. squarrosa. Grazing directly drove the change in P resorption efficiency of S. grandis. Our results suggest that large variations in nutrient resorption patterns among plant species depend on leaf nutritional status and nutrient-use strategies under overgrazing, and indicate that overgrazing may have indirect effects on plant-mediated nutrient cycling via inducing shifts in the dominance of the three plant species.

Nevado de Toluca: habitat for Romerolagus diazi?

The volcano rabbit (Romerolagus diazi), also known as teporingo or zacatuche, is a small rabbit that is endemic to Mexico. In this study we characterized its potential habitat in the Area of Protection of Flora, and Fauna Nevado de Toluca, Mexico. Between April 2016 and November 2017, we sampled 1,807 units to determine the presence of this species using indirect evidence. We found dung pellets that could be attributed to R. diazi in 41 (2.27 %) of the sampled units. In 10 % of these units, we set up camera traps to confirm the presence of the species. Sites with presumed R. diazi pellets were characterised by rocky terrain, with Pinus hartwegii as the dominant tree species, and Festuca tolucensis as the dominant grass. Overall herbaceous cover was over 70 %. Sites observed to have a negative effect on the presence of the pellets were areas with livestock grazing and induced burning. The results of camera trapping did not reveal the presence of R. diazi in Nevado de Toluca.

Competition Indices Identify Forb Species That Promote Overyielding of a Dominant Grass in Grassland Restoration

Overyielding is a common phenomenon. Overyielding of dominant grasses when in competition with common forbs during grassland restoration could lead to lower plant diversity. My objective was to characterize overyielding of Andropogon gerardii in competition with fcommon forbs. I collected soils representing different stages of restoration (0, 4, and 16 years restored) and conducted a pairwise competition experiment with a dominant grass, Andropogon gerardii, in competition with four subordinate forbs (Oligoneuron rigidum L., Liatris punctata Hook, Lespedeza capitata Michx., or Desmanthus illinoensis Michx.). Relative yield indices (RY) were calculated by comparison with a two-individual monoculture of A. gerardii with both per grass biomass and per grass net absolute tiller appearance rate (TAR). Overyielding of A. gerardii was in competition with Oligoneuron rigidum was indicated by RY values (greater than1) using both biomass and TAR measurements. These findings suggest that O. rigidum should be given low priority for inclusion in tallgrass prairie restoration seed mixes.