Effects of range condition on the temporal diet selection by goats in steppe rangelands of Iran

One of the key factors in managing a rangeland is to determine the relative preference of its major plant species by thegrazing livestock. Preference value of each plant species is affected by plant type, companion plants, availability byanimals, phenological stage, climate condition, and the livestock species. We investigated the grazing behaviour of anative goat (Garizi) in the steppe rangelands of Iran, from May to November 2004. The study was conducted within oroutside of an enclosure, representing a Good Condition (GC) or a Poor Condition (PC) rangeland, respectively. Flocks ofsix goats were selected randomly and their grazing behaviour was monitored by chronometers. Grazing preference wasconsidered as the time goats had spent for grazing each plant species. The grazing season was divided into 4 grazingperiods, 45 days each. Data recording in the GC and PC sites was repeated 3 times during each grazing period. Theexperiment was designed as the completely randomized blocks. In the GC site, grazing pressure on the perennial grassStipa barbata and the perennial chenopod Salsola rigida was low at the beginning of the grazing period, but it wasincreased towards the end of the grazing season. In the PC site, the main grazing pressure was on noxious plants such asScariola orientalis, Launaea acanthoides, and Cousinia deserti. For both GC and PC sites, the time of grazing hadsignificant influences on relative abundances of annual plants and plant litter, which subsequently changed diet selectionby the Garizi goat. One of the key factors in managing a rangeland is to determine the relative preference of its major plant species by thegrazing livestock. Preference value of each plant species is affected by plant type, companion plants, availability byanimals, phenological stage, climate condition, and the livestock species. We investigated the grazing behaviour of anative goat (Garizi) in the steppe rangelands of Iran, from May to November 2004. The study was conducted within oroutside of an enclosure, representing a Good Condition (GC) or a Poor Condition (PC) rangeland, respectively. Flocks ofsix goats were selected randomly and their grazing behaviour was monitored by chronometers. Grazing preference wasconsidered as the time goats had spent for grazing each plant species. The grazing season was divided into 4 grazingperiods, 45 days each. Data recording in the GC and PC sites was repeated 3 times during each grazing period. Theexperiment was designed as the completely randomized blocks. In the GC site, grazing pressure on the perennial grassStipa barbata and the perennial chenopod Salsola rigida was low at the beginning of the grazing period, but it wasincreased towards the end of the grazing season. In the PC site, the main grazing pressure was on noxious plants such asScariola orientalis, Launaea acanthoides, and Cousinia deserti. For both GC and PC sites, the time of grazing hadsignificant influences on relative abundances of annual plants and plant litter, which subsequently changed diet selectionby the Garizi goat

Decoupling of soil nutrient cycles as a function of aridity in global drylands

18 páginas.- 10 figuras.- 72 referencias.- Online Content Any additional Methods, Extended Data display items and Source Data are available in the online version of the paper; references unique to these sections appear only in the online paper..- Puede conseguir el texto completo en el Portal de la producción científica de la Universidad Complutense de Madrid https://produccioncientifica.ucm.es/documentos/5ec78dc52999520a1d557660 .- o en lel respositorio institucional CONICET digital https://ri.conicet.gov.ar/bitstream/handle/11336/29204/CONICET_Digital_Nro.ead4e2ed-0da6-4041-814b-259e8f27bbf6_D.pdf?sequence=5&isAllowed=yThe biogeochemical cycles of carbon (C), nitrogen (N) and phosphorus (P) are interlinked by primary production, respiration and decomposition in terrestrial ecosystems1. It has been suggested that the C, N and P cycles could become uncoupled under rapid climate change because of the different degrees of control exerted on the supply of these elements by biological and geochemical processes1,2,3,4,5. Climatic controls on biogeochemical cycles are particularly relevant in arid, semi-arid and dry sub-humid ecosystems (drylands) because their biological activity is mainly driven by water availability6,7,8. The increase in aridity predicted for the twenty-first century in many drylands worldwide9,10,11 may therefore threaten the balance between these cycles, differentially affecting the availability of essential nutrients12,13,14. Here we evaluate how aridity affects the balance between C, N and P in soils collected from 224 dryland sites from all continents except Antarctica. We find a negative effect of aridity on the concentration of soil organic C and total N, but a positive effect on the concentration of inorganic P. Aridity is negatively related to plant cover, which may favour the dominance of physical processes such as rock weathering, a major source of P to ecosystems, over biological processes that provide more C and N, such as litter decomposition12,13,14. Our findings suggest that any predicted increase in aridity with climate change will probably reduce the concentrations of N and C in global drylands, but increase that of P. These changes would uncouple the C, N and P cycles in drylands and could negatively affect the provision of key services provided by these ecosystems.This research is supported by the European Research Council (ERC) under the European Community's Seventh Framework Programme (FP7/2007-2013)/ERC Grant agreement no. 242658 (BIOCOM), and by the Ministry of Science and Innovation of the Spanish Government, grant no. CGL2010-21381. CYTED funded networking activities (EPES, Acción 407AC0323). M.D.-B. was supported by a PhD fellowship from the Pablo de Olavide University.Peer reviewe

Plant Functional Types as Indices of Post-Fire Succession in a Semiarid Rangeland

Secondary succession after wildfire usually leads to vegetation types that can differ with the original vegetation in terms of forage productivity and community stability. Plant functional types (PFTs) can be used as ecological indices for assessing effects of disturbances on the natural plant communities. Accordingly, this research was aimed to identify, classify and analyze PFTs in three rangeland sites: burnt in 2004, in 2008, and control (2010), in Jowzak, Northern Khorasan, Iran. Floristic list, percentage cover and 24 morphological, phonological and reproductive plant traits were recorded within 1m2quadrates. PFT’s were determined by applying hierarchical cluster analyses and discriminant function analysis on the matrices of 45 species24 traits and 45 species3 sites, using SPSS software. Four different PFTs were identified. Leaf wet weight, life forms and Twig dry matter contents were the most important traits for PFT classification. Two functional types identified as adapted to fire, and two groups as functional types sensitive to fire. According to the results of this research, the most important indices for the effect of fire on secondary succession of Jowzak rangelands can be the reduction of hemicryptophytes perennial geophytes and annuals, increase of plant height , seed size, seed weight, specific leaf area and leaf dry matter content, and decrease of stem weight, leaf and twig dry matter content

Species Diversity and Identification of Plant Functional Types of Woodland in Shimbar Protected Area, Khuzestan Provience

Measuring the diversity of plant functional types, identifying their characteristics, and their classification will help to identification of woodland germination capacity and implementing appropriate range management programs. The study was designed to measure the species diversity and to identify plant functional types in three adjacent ecological sites in Shimbar or Shirin Bahar region. During winter, spring and summer since 2013 to 2014, the data regarding the percentage of species coverage were taken from 106 plots using stratified random sampling method in the south facing slopes, north facing slopes and the wetland. Species diversity (Alpha diversity) and habitat diversity (Beta diversity) were measured using PAST and SDR softwares. According to the Shannon-Wiener and Simpson indices the greatest species diversity were found in the wetland, south slopes and north slopes respectively. Species richness was higher in northern slope than northern slopes and the lowest in wetland. For classifying and determining response of vegetation to environmental factors and identifying plant functional types, about 66 resistance to disturbance characters were measured and subjected to clustering by Ward method in R software. The annual and perennial species were classified into 21 and trees and shrubs to 8 classes

Grass-Shrub Associations over a Precipitation Gradient and Their Implications for Restoration in the Great Basin, USA

As environmental stress increases positive (facilitative) plant interactions often predominate. Plant-plant associations (or lack thereof) can indicate whether certain plant species favor particular types of microsites (e.g., shrub canopies or plant-free interspaces) and can provide valuable insights into whether “nurse plants” will contribute to seeding or planting success during ecological restoration. It can be difficult, however, to anticipate how relationships between nurse plants and plants used for restoration may change over large-ranging, regional stress gradients. We investigated associations between the shrub, Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis), and three common native grasses (Poa secunda, Elymus elymoides, and Pseudoroegneria spicata), representing short-, medium-, and deep-rooted growth forms, respectively, across an annual rainfall gradient (220–350 mm) in the Great Basin, USA. We hypothesized that positive shrub-grass relationships would become more frequent at lower rainfall levels, as indicated by greater cover of grasses in shrub canopies than vegetation-free interspaces. We sampled aerial cover, density, height, basal width, grazing status, and reproductive status of perennial grasses in canopies and interspaces of 25–33 sagebrush individuals at 32 sites along a rainfall gradient. We found that aerial cover of the shallow rooted grass, P. secunda, was higher in sagebrush canopy than interspace microsites at lower levels of rainfall. Cover and density of the medium-rooted grass, E. elymoides were higher in sagebrush canopies than interspaces at all but the highest rainfall levels. Neither annual rainfall nor sagebrush canopy microsite significantly affected P. spicata cover. E. elymoides and P. spicata plants were taller, narrower, and less likely to be grazed in shrub canopy microsites than interspaces. Our results suggest that exploring sagebrush canopy microsites for restoration of native perennial grasses might improve plant establishment, growth, or survival (or some combination thereof), particularly in drier areas. We suggest that land managers consider the nurse plant approach as a way to increase perennial grass abundance in the Great Basin. Controlled experimentation will provide further insights into the life stage-specific effectiveness and practicality of a nurse plant approach for ecological restoration in this region