Range Of Grasslands Research Articles

Major distribution shifts are projected for key rangeland grasses under a high-emission scenario in East Africa at the end of the 21st century

Grassland landscapes are important ecosystems in East Africa, providing habitat and grazing grounds for wildlife and livestock and supporting pastoralism, an essential part of the agricultural sector. Since future grassland availability directly affects the future mobility needs of pastoralists and wildlife, we aim to model changes in the distribution of key grassland species under climate change. Here we combine a global and regional climate model with a machine learning-based species distribution model to understand the impact of regional climate change on different key grass species. The application of a dynamical downscaling step allows us to capture the fine-scale effects of the region’s complex climate, its variability and future changes. We show that the co-occurrence of the analysed grass species is reduced in large parts of eastern Africa, and particularly in the Turkana region, under the high-emission RCP8.5 scenario for the last 30 years of the 21st century. Our results suggest that future climate change will alter the natural resource base, with potentially negative impacts on pastoralism and wildlife in East Africa.

Suppression of non‐native and native grass seed germination using mustard seed meal and mulch biofumigation

AbstractNon‐native annual grasses have invaded western rangelands in the United States, and novel approaches are needed to supplement existing management strategies. The aim of this study was to investigate biofumigation, the use of Brassicaceae products to suppress weeds, as a control for two non‐native annual grasses (cheatgrass, Bromus tectorum and ventenata, Ventenata dubia) and its effects on two dominant native perennial grasses (bluebunch wheatgrass, Pseudoroegneria spicata and Idaho fescue, Festuca idahoensis). We tested the effect of the biofumigant Brassica juncea (brown mustard), applied as seed meal and mulch, on germination metrics of the four grass species in Petri dishes. Germination metrics included emergence and viability, time to cotyledon and radicle emergence and their lengths at 14 days after sowing. Impacts on emergence and viability were assessed using a binomial mixed effects model, while time to cotyledon and radicle emergence and lengths were assessed using linear mixed effects models. Seed meal reduced emergence and viability at lower application rates for V. dubia and F. idahoensis than the other two species. Mulch did not consistently reduce emergence or viability. P. spicata was the least inhibited by the biofumigants. When using seed meal, radicle emergence and length were inhibited in B. tectorum, V. dubia and F. idahoensis and cotyledon emergence and length were inhibited for all. The mulch did not impact these metrics consistently and may not be a viable management tool. The use of seed meal biofumigant to suppress undesired annual grasses in rangelands seems promising, but response is species‐specific.

Generation of new equations to estimate aerial biomass based on morphological variables obtained from grasses in rangelands of Nuevo León, Mexico

La estimación de biomasa aérea de pastos contribuye a realizar un manejo eficiente y sostenible de los agostaderos. El objetivo del presente estudio fue generar nuevas ecuaciones para estimar la biomasa aérea de pastos presentes en agostaderos, en Nuevo León, México, basado en datos colectados del total (n=745) de los individuos de las cinco especies de pastos: Cenchrus ciliaris Linnaeus, Pappophorum bicolor Fourn, Aristida purpurea Nutt, Tridens texanus Watson y Paspalum pubiflorum Fourn presentes en las parcelas de muestreo. Utilizando la altura máxima y la de los tallos vegetativos, los diámetros aéreo, basal y comprimido, y volúmenes medidos en cada uno de los individuos colectados, se generaron ecuaciones lineales (stepwise) y no lineales, para estimar la biomasa aérea (base materia seca) de los pastos cortados a ras de suelo. Se seleccionaron seis ecuaciones generales con el mejor ajuste estadístico para el total de las especies colectadas. La ecuación general III tuvo los mejores valores de R2=0.88 y AIC=3079, utilizando las cinco variables evaluadas. La ecuación general IV estimó con R2=0.86 y AIC= 3530, utilizando solo la variable de diámetro comprimido. Las ecuaciones específicas seleccionadas estimaron la biomasa aérea de los pastos Cenchrus ciliaris (R2=0.88, r=0.94), Pappophorum bicolor (R2=0.86, r=0.92), Aristida purpurea (R2=0.92, r=0.96), Tridens texanus (R2=0.91, r=0.96), y Paspalum pubiflorum (R2=0.93, r=0.97). Las nuevas ecuaciones son una alternativa confiable para estimar indirectamente la biomasa aérea de los pastos de los agostaderos del noreste de México, de forma más rápida y menos costosa que el método tradicional.

Effects of Hemp Seed on the Production, Fatty Acid Profile, and Antioxidant Capacity of Milk from Goats Fed Hay or a Mixed Shrubs-Grass Rangeland.

The research objective was to evaluate the effect of dietary incorporation of hemp seeds in goats fed with hay or mixed shrubs-grass rangeland on the production, FA profile and health-related lipid indices, antioxidant content and total antioxidant capacity of milk, with the purpose to increase the content of beneficial ingredients in milk and to improve its functional activity. Forty indigenous Carpathian goats were allocated into two groups according to the type of basic forage in their diet: hay (H) or mixed shrubs-grass rangeland (SG); each of them was further divided into two subgroups according to the presence of Hs in the concentrate mixture (250 g/kg) or not. Milk production was determined, and milk samples were collected and analyzed for fat, protein, lactose, and cholesterol content, as well as FA profile, lipophilic antioxidant content (α-tocopherol and retinol), and milk TAC. SG goats gave less milk (p < 0.01) but with higher milk fat (p < 0.001) and lower cholesterol content (p < 0.01) than H goats, while milk protein and lactose contents were not affected. Supplementing the diet with Hs caused a significant increase in milk production (p < 0.05) and milk fat content (p < 0.001) and a decrease in cholesterol content (p < 0.05). Grazing compared to indoor feeding but also supplementing the diet with Hs had the effect of decreasing the proportion of SFAs and increasing the concentrations of polyunsaturated FA (PUFA) in goat milk fat (p < 0.01). Fats in the milk of SG goats compared to H, but also in those supplemented with Hs, showed significantly higher proportions of vaccenic acid (VA), rumenic acid (CLA c-9,t-11) and omega-3 FA (α-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosapentaenoic acid (DPA)) which are considered healthy for consumers. The feeding system based on SG and the diet supplementation with Hs ensured the best nutritional and functional quality of milk, confirmed by the FA profile, antioxidant content, and by the value of health-related lipid indices (n-6/n-3 FA ratio and hypo-/hypercholesterolemia, atherogenic index (AI), thrombogenic index (TI), and health promotion index (HPI)). The results of our work will be useful for the development of optimal nutritional strategies that improve the FA profile and the antioxidants content in goat milk, with beneficial effects on human health.

EFFECTS OF WEED CONTROL METHODS ON WEEDS AND PRODUCTIVITY OF RANGE GRASSES IN SEMI-ARID KENYA

&lt;p&gt;&lt;strong&gt;Background:&lt;/strong&gt; Weeds are a common occurrence and challenge in different crops eventually influencing crop development and yields. Weed control and management are key in enhancing the productivity of cultivated pastures. In semi-arid Kenyan drylands, the main methods employed for weed management are manual cultural practices and recently, the application of commercial herbicides. &lt;strong&gt;Objective:&lt;/strong&gt; To evaluate the effects of two weed control methods on weed characteristics and productivity of four rangeland grasses commonly used in reseeding and pasture improvement in a semi-arid environment. &lt;strong&gt;Methodology:&lt;/strong&gt; In a randomized complete block design in a field experiment, we determined the effects of two weed control methods (manual and herbicide use) in four rangeland cultivated grasses. These are Buffel grass (&lt;em&gt;Cenchrus ciliaris&lt;/em&gt;), Horsetail grass (&lt;em&gt;Chloris roxburghiana&lt;/em&gt;), Masaai love grass (&lt;em&gt;Eragrostis superba&lt;/em&gt;) and Bush rye (&lt;em&gt;Enteropogon macrostachyus&lt;/em&gt;). Weed characteristics (species, density, diversity and weed biomass,) were evaluated, as well as the effectiveness of the weed control methods in the grasses. &lt;strong&gt;Results:&lt;/strong&gt; Broad-leaved weeds and annual grasses were prevalent in the established grasses. Generally, higher grass dry matter yields were obtained in &lt;em&gt;Cenchrus ciliaris&lt;/em&gt; grasses (2.05 t h&lt;sup&gt;-1&lt;/sup&gt;) while lowest yields were in &lt;em&gt;Chloris roxburghiana&lt;/em&gt; (1.2 ton ha&lt;sup&gt;-1&lt;/sup&gt;). Weed management interventions increased biomass production in the grasses by a mean of 19% in general. The mean yield increase varied with species and weed control method ranging from 8-39%. Weed control methods significantly reduced weed density, diversity and eventually weed biomass within the grass species. The efficacy of manual weed control and chemical application was in the range of 27-74%. &lt;strong&gt;Implications: &lt;/strong&gt;Weed control is, therefore, necessary if one is to realize higher productivity and returns in cultivated pasture and fodder systems in semi-arid environments. &lt;strong&gt;Conclusion:&lt;/strong&gt; Both chemical and manual control methods of weed control are important and effective approaches to manage weeds in pasture systems in semi-arid environments.&lt;strong&gt; &lt;/strong&gt;&lt;/p&gt;

Differentiating grazing-induced rangeland grass nutrition status in situ using near infrared reflectance

Assessing the nutrient content of rangeland grass using earth observation technologies presents opportunities for non-destructive, rapid and repetitive appraisals in support of rangeland management. The biochemical-related concentrations of macronutrients (N, P, K, Ca, Mg) are among the factors that influence near infrared reflectance (ρNIR) by a turgid leaf. High grazing intensity (GI) enhances nutrient recycling in rangelands, resulting in high concentrations in aboveground grass tissue. This study sought to establish whether grazing-induced macronutrient abundance in rangeland grass can be remotely sensed in situ through ρNIR in the multiple species natural settings. Sampling was conducted at peak grass growth stage in large savannah rangelands with similar grass species mixtures, in low moisture stress conditions. The sampling was widely distributed in GI-contrasted livestock and wild grazer rangelands, and in grazing-restricted control sites. Two species representing high and low nutrient grass species, respectively, were sampled. At each sampling site (N = 116), reflectance was measured in the 350–2500 nm range from leaf and stem tissue of healthy-looking specimens of the two species (≤10 m apart), using a 1.1 nm – 1.4 nm resolution spectroradiometer. Macronutrient concentrations (MNC) in the tissue were then determined in the laboratory. For each species, the hyperspectral NIR (λ700 – 1100 nm) reflectance was averaged per sampling site. Individual and total MNC, respectively, were correlated with the hyperspectral ρNIR, and then with atmospheric effect-corrected ρNIR from 10 m-resolution, field sampling-concurrent Sentinel-2 MSI multispectral images. For each sampling site, the two species’ hyperspectral ρNIR values, individual and total MNC, respectively, were then averaged. Respective models relating the paired hyperspectral ρNIR and averaged MNC were developed, by linear regression and partial least squares regression (PLSR). Tissue MNC were lowest in the control sites and higher in the grazed rangelands. Covariance in MNC in the two species suggested location-context similarities in all grasses. Individual and total MNC, respectively, had statistically significant (p < 0.01) negative correlations with both tissue level hyperspectral and multispectral ρNIR. The negative relationship was detected on empirical line-retrieved ρNIR on historical Hyperion hyperspectral images. PLSR yielded a more accurate predictive model (R2 = 0.760) than linear regression (R2 = 0.601, F = 138.415, p < 0.0001). The study shows that there are possibilities to remotely sense grazing-induced MNC in aboveground grass tissue through changes in ρNIR.

Multi-Species Inference of Exotic Annual and Native Perennial Grasses in Rangelands of the Western United States Using Harmonized Landsat and Sentinel-2 Data

The invasion of exotic annual grass (EAG), e.g., cheatgrass (Bromus tectorum) and medusahead (Taeniatherum caput-medusae), into rangeland ecosystems of the western United States is a broad-scale problem that affects wildlife habitats, increases wildfire frequency, and adds to land management costs. However, identifying individual species of EAG abundance from remote sensing, particularly at early stages of invasion or growth, can be problematic because of overlapping controls and similar phenological characteristics among native and other exotic vegetation. Subsequently, refining and developing tools capable of quantifying the abundance and phenology of annual and perennial grass species would be beneficial to help inform conservation and management efforts at local to regional scales. Here, we deploy an enhanced version of the U.S. Geological Survey Rangeland Exotic Plant Monitoring System to develop timely and accurate maps of annual (2016–2020) and intra-annual (May 2021 and July 2021) abundances of exotic annual and perennial grass species throughout the rangelands of the western United States. This monitoring system leverages field observations and remote-sensing data with artificial intelligence/machine learning to rapidly produce annual and early season estimates of species abundances at a 30-m spatial resolution. We introduce a fully automated and multi-task deep-learning framework to simultaneously predict and generate weekly, near-seamless composites of Harmonized Landsat Sentinel-2 spectral data. These data, along with auxiliary datasets and time series metrics, are incorporated into an ensemble of independent XGBoost models. This study demonstrates that inclusion of the Normalized Difference Vegetation Index and Normalized Difference Wetness Index time-series data generated from our deep-learning framework enables near real-time and accurate mapping of EAG (Median Absolute Error (MdAE): 3.22, 2.72, and 0.02; and correlation coefficient (r): 0.82, 0.81, and 0.73; respectively for EAG, cheatgrass, and medusahead) and native perennial grass abundance (MdAE: 2.51, r:0.72 for Sandberg bluegrass (Poa secunda)). Our approach and the resulting data provide insights into rangeland grass dynamics, which will be useful for applications, such as fire and drought monitoring, habitat suitability mapping, as well as land-cover and land-change modelling. Spatially explicit, timely, and accurate species-specific abundance datasets provide invaluable information to land managers.

Plant Morphoecological Traits, Grass-Weed Interactions and Water Use Efficiencies of Grasses Used for Restoration of African Rangelands

Degradation characterized by depleted vegetation cover is a serious environmental problem in African rangelands. It poses a serious threat to millions of pastoralists and agropastoralists who depend on livestock as a source of livelihood. Consequently, there has been a growing global interest to consolidate efforts to restore degraded ecosystems. For example, the UN decade of Ecosystem Restoration initiative aims at uniting the world behind a common goal of preventing, halting and reversing the degradation of ecosystems. Grass reseeding using native perennial species has been identified as one of the practical ecological strategies for restoring degraded African rangelands, enhancing vegetation cover and forage production. Knowledge of the multifaceted performance of African rangeland grasses in terms of morphoecological traits, interaction with weeds and water use efficiencies is however largely limited and often elusive. Perennial grasses indigenous to African rangelands Cenchrus ciliaris L. (African foxtail grass), Enteropogon macrostachyus (Hochst. Ex A. Rich.) Monro ex Benth. (Bush rye grass) and Eragrostis superba Peyr. (Maasai love grass), were established in an African semi-arid rangeland under natural conditions to fill this knowledge gap. Morphoecological plant traits: aboveground biomass (shoot, leaf and stem) production, plant densities, basal cover, tiller densities and plant height were measured 9 months after establishment. Interaction between the target grass species and weeds and water use efficiencies (WUE) were also determined. Enteropogon macrostachyus displayed significantly higher values for plant densities, tiller densities and basal cover, indices commonly used to estimate the potential of grasses for ecological restoration. Eragrostis superba produced the highest shoot biomass and water use efficiencies. This is attributed to its higher leafy biomass fraction. Higher aboveground biomass production of E. superba demonstrate its suitability for enhancing rangeland productivity. Cenchrus ciliaris suppressed the weeds. This is linked to its aggressive and allelopathic nature. In conclusion, the three perennial grasses displayed distinct morphoecological traits. In order to achieve successful seed-based restoration of degraded African rangelands using native perennial grasses, careful selection species to maximize on their unique traits is recommended. Ultimately, this selection process should match the desired restoration outcomes and subsequent use of the rangeland.

Forage value of vegetative leaf and stem biomass fractions of selected grasses indigenous to African rangelands

Context Rangeland grasses native to Africa constitute the main diet for free-ranging livestock and wild herbivores. Leaf:stem ratio is a key characteristic used for assessing quality of forages. However, studies to determine the allocation of biomass to leaves and stems as well as chemical components and nutritive value, especially of grasses in African rangelands, are rare. Aim This study was conducted to establish biomass allocation and chemical and mineral components in leaf and stem fractions of three grasses, Eragrostis superba, Enteropogon macrostachyus and Cenchrus ciliaris, all indigenous to African rangelands. Methods Plant height, plant densities, plant tiller densities and biomass yields were estimated at the elongation stage, before inflorescence. Chemical and mineral components were determined from biomass harvested at the vegetative phase for all three grass species. Dry matter, ash content, organic matter, crude protein, neutral detergent fibre, acid detergent fibre, acid detergent lignin, and calcium, phosphorus and potassium contents were determined. Key results Enteropogon macrostachyus displayed significantly greater plant and tiller densities and plant height than the other two species. Leaf and stem biomass fractions varied significantly (P &lt; 0.05) among grasses. Leaf:stem ratio of E. superba was double that of E. macrostachyus and C. ciliaris. Crude protein and organic matter yields and net energy for lactation were highest (P &lt; 0.05) in E. superba leaf biomass, as was Ca content. Conclusions Eragrostis superba demonstrated greater potential as a forage species for ruminant animal production than E. macrostachyus and C. ciliaris. Implications Eragrostis superba is a key forage species that warrants promotion in pasture establishment programs in its native environments.

Quantifying plant-soil-nutrient dynamics in rangelands: Fusion of UAV hyperspectral-LiDAR, UAV multispectral-photogrammetry, and ground-based LiDAR-digital photography in a shrub-encroached desert grassland

Rangelands cover 70% of the world's land surface, and provide critical ecosystem services of primary production, soil carbon storage, and nutrient cycling. These ecosystem services are governed by very fine-scale spatial patterning of soil carbon, nutrients, and plant species at the centimeter-to-meter scales, a phenomenon known as “islands of fertility”. Such fine-scale dynamics are challenging to detect with most satellite and manned airborne platforms. Remote sensing from unmanned aerial vehicles (UAVs) provides an alternative option for detecting fine-scale soil nutrient and plant species changes in rangelands tn0020 smaller extents. We demonstrate that a model incorporating the fusion of UAV multispectral and structure-from-motion photogrammetry classifies plant functional types and bare soil cover with an overall accuracy of 95% in rangelands degraded by shrub encroachment and disturbed by fire. We further demonstrate that employing UAV hyperspectral and LiDAR fusion greatly improves upon these results by classifying 9 different plant species and soil fertility microsite types (SFMT) with an overall accuracy of 87%. Among them, creosote bush and black grama, the most important native species in the rangeland, have the highest producer's accuracies at 98% and 94%, respectively. The integration of UAV LiDAR-derived plant height differences was critical in these improvements. Finally, we use synthesis of the UAV datasets with ground-based LiDAR surveys and lab characterization of soils to estimate that the burned rangeland potentially lost 1474 kg/ha of C and 113 kg/ha of N owing to soil erosion processes during the first year after a prescribed fire. However, during the second-year post-fire, grass and plant-interspace SFMT functioned as net sinks for sediment and nutrients and gained approximately 175 kg/ha C and 14 kg/ha N, combined. These results provide important site-specific insight that is relevant to the 423 Mha of grasslands and shrublands that are burned globally each year. While fire, and specifically post-fire erosion, can degrade some rangelands, post-fire plant-soil-nutrient dynamics might provide a competitive advantage to grasses in rangelands degraded by shrub encroachment. These novel UAV and ground-based LiDAR remote sensing approaches thus provide important details towards more accurate accounting of the carbon and nutrients in the soil surface of rangelands.

Sheep grazing differentially affects the canopy attributes and functional diversity of shrubs and perennial grasses in arid rangelands

We analysed how changes in community attributes promoted by domestic grazing are reflected on functional traits in canopies of shrubs and perennial grasses in rangelands of the Patagonian Monte. We selected four sites across a gradient of grazing pressure and assessed (i) changes in plant cover, and species richness and diversity and (ii) changes in functional traits (community weighted mean: CWM, functional diversity and redundancy) related to plant growth (leaf N concentration, height of the plant, and specific leaf area-SLA) in shrub and perennial grass canopies. Shrub cover decreased and species and functional diversity increased with increasing grazing pressure. Nonsignificant changes were found in shrub species richness and functional redundancy across the grazing gradient. Positive relationships were found between shrub species diversity and CWM of SLA, and leaf N, while CWM-height was not related to grazing pressure. Perennial grass cover decreased steadily with grazing pressure, while species richness decreased significantly at high grazing pressure. Perennial grass diversity, functional diversity and redundancy of functional plant traits, and CWM-height increased at intermediate grazing pressure, while the inverse pattern was observed for CWM of SLA and leaf N. These results highlighted that species diversity was the community attribute that best reflected functional changes induced by grazing pressure in shrub and perennial grass canopies in these rangelands. We concluded that shrubs persist under high grazing pressure increasing species and functional diversity of relevant plant traits, while perennial grass canopies were only able to persist under intermediate grazing pressure.

Invasive grasses in South Texas rangelands: historical perspectives and future directions

AbstractSouth Texas is home to a high diversity of species due to its location at the confluence of subtropical, desert, and coastal ecoregions. Historical overgrazing of South Texas rangelands transformed the savanna and prairie to a landscape dominated by woody plants and shrubs interspersed with low seral grass species and bare ground. During the first half of the 20th century, exotic grass species, coupled with the application of industrial agricultural practices appeared to be the future of forage production in South Texas and elsewhere. Several of these exotic species, namely King Ranch bluestem [Bothriochloa ischaemum(L.) Keng], Kleberg bluestem [Dichanthium annulatum(Forssk.) Stapf], Angelton bluestem [Dichanthium aristatum(Poir.) C.E. Hubbard], buffelgrass [Pennisetum ciliare(L.) Link], guineagrass [Urochloa maxima(Jacq.) R. Webster], Lehmann lovegrass (Eragrostis lehmannianaNees), and Bermudagrass [Cynodon dactylon(L.) Pers.], have escaped pasture cultivation. Additionally, the native grass tanglehead [Heteropogon contortus(L.) P. Beauv. ex Roem. &amp; Schult.] has begun displaying invasive behaviors. The monoculture growth habit of these species simplifies vegetation structure, reduces biodiversity, and decreases habitat for many species of wildlife. These grasses also alter natural fire regimes and nutrient cycling. This landscape-level transformation of vegetation composition and structure requires monitoring to quantify and assess the spatial and temporal distributions of invasive species as a basis to inform management practices. Current advances in remote sensing technologies, such as very high spatial resolution coupled with daily satellite imagery and unmanned aerial vehicles, are providing tools for invasive vegetation monitoring. We provide a synthesis of the natural history of these grasses, including their introductions, an overview of remote sensing applications in South Texas, and recommendations for future management practices.

Water quality of an integrated crop–livestock system in the northern Great Plains

AbstractImpacts of integrated crop–livestock (ICL) systems on water quality have not been well studied. Water quality parameters were quantified for two 30‐min rainfall simulations in wheat (Triticum aestivum L.)–cover crop, cover crop, and rangeland grass control phases of a long‐term ICL study site in Mandan, ND, in 2017 and 2018. Both pre‐graze and post‐graze simulations were conducted. Nitrate‐N (NO3−–N), nitrite‐N (NO2−–N), ammonia‐N (NH4+–N), phosphate‐P (PO43−–P), and total suspended solid (TSS) concentrations and loads were evaluated in surface runoff water, along with concentrations of NO3−–N, NO2−–N, NH4+–N, and PO43−–P in infiltration water. Non‐parametric ranked two‐way analysis of variance was used to evaluate differences for vegetation type and grazing as fixed effects, with year as a random effect. Surface runoff concentrations of NO3−–N and NH4+–N were significantly different with cover crop and wheat phases being greater than grass. A grazing effect was also observed with pre‐graze significantly greater than post graze for NO2−–N, NH4+–N, PO43−–P, and TSS surface runoff concentrations. For infiltration water concentrations, similar significant effects of vegetation type were observed for NO3−–N and PO43−–P, while pre‐graze was also greater than post‐graze for NO2−–N and PO43−–P. Due to variable runoff volumes, no significant differences were observed for loads of any parameters. Minimal runoff volumes (0–6.7 L) and significant vegetation and grazing effects in nutrient infiltration water concentrations highlight the importance of infiltration in such studies, particularly at sites in the northern Great Plains.

Hydrothermal Germination Models: Assessment of the Wet‐Thermal Approximation of Potential Field Response

Hydrothermal (HT) models can be used to characterize seed germination response to field‐variable conditions of temperature (T) and water potential (Ψ). Hydrothermal response data are relatively difficult to generate, which limits their utility for large‐scale comparisons of inter‐ and intraspecies germination response. Previous studies have hypothesized that HT germination response can be estimated using a simple model for thermal‐time accumulation above a fixed threshold of environmental Ψ (wet‐thermal [WT] model). The purpose of this study was to test this hypothesis by explicitly comparing HT and WT germination rates and estimated cumulative germination response of 13 rangeland grass seedlots under simulated conditions of field‐variable T and Ψ. We used a 44‐yr weather record to parameterize a seedbed‐microclimate model for estimation of hourly T and Ψ at seeding depth for a sandy loam soil type at the Orchard field test site in southwestern Ada County, Idaho. Hydrothermal and WT germination responses for each hour of the simulation were estimated for 13 range grass seedlots. We found that overestimation of germination rate by thermal accumulation at low Ψ contributed relatively little to WT model error rates, and that &gt;95% of the variability in predicted germination response could be explained by WT germination response above a Ψ threshold of −0.3 to −0.5 MPa. Given the pulse‐like nature of favorable germination conditions in the field, this modeling approach may have immediate and wide potential application, as there are a relatively large number of thermal‐germination datasets currently available for rangeland plant species.

SOME OBSERVATIONS ON SPECIES COMPOSITION AND DETERIORATION OF CROP PLANTATIONS AND FOREST FLORA BY PORCUPINES IN CONSORT WITH CONTROL TECHNIQUES

The goal of this article is to inform community regarding porcupines damage, and deliver guidelines for their harmless, real and liable elimination. The utmost apparent attribute of porcupines is their extensive, piercing and shakable quills, which shelter backs of the physiques that make them hit, as a threatening to probable raiders. In general, porcupines occur the maximum in mountainous and gravelly states, however these may adjust in many territories like extremely wet plantations and somewhat territory comprising of prairies, foothills, deserts and tropical forests. Porcupines can become a pest by eating of carrots and other root vegetables, clovers, roots, fruits as well as foraging on the farm crops. A definite indication of porcupine burrow is a mound of feces at entering site of cave or hollow tree. In this global region, Hystrix indica Kerr is most plentiful and scattered species, and has been familiarized as a severe pest of fruit orchards, vegetables, flowering plants, forage grasses in pastures or rangelands and traditional as well as non-traditional crops. When porcupines inflict optimum damage, then their control actions must be adopted. A pest controlling expert can provide skill to recognize the porcupines problematic and decide the superlative promising way out to decide the pest annoyance. Prior to executing a loss managing method, evaluate the porcupines incidence by means of watching for shattered quills, fecal masses beneath nourishing and sleeping plants, or distinctive injury marks to trees in a region. Manipulate habitat to attract more natural predators to control porcupine populations, place aluminum flashing around mature tree trunks and enclose small trees with wire baskets, and enclosure areas with electric or nonelectric fencing, to stop porcupines from gnawing at their bark. Implement forest management practices to reduce food supply and some wood preservatives applied to trees, and use of poison baits may provide partial damage relief. During late spring and summer activity periods, shooting of pest is most effective option, and use steel leg-hold traps lured by salt-soaked ingredients and placing proximate to alive burrows or else frequently used tracks.

The positive relationships between plant coverage, species richness, and aboveground biomass are ubiquitous across plant growth forms in semi-steppe rangelands

The positive relationships between biodiversity and aboveground biomass are important for biodiversity conservation and greater ecosystem functioning and services that humans depend on. However, the interaction effects of plant coverage and biodiversity on aboveground biomass across plant growth forms (shrubs, forbs and grasses) in natural rangelands are poorly studied. Here, we hypothesized that, while accounting for environmental factors and disturbance intensities, the positive relationships between plant coverage, biodiversity, and aboveground biomass are ubiquitous across plant growth forms in natural rangelands. We applied structural equation models (SEMs) using data from 735 quadrats across 35 study sites in semi-steppe rangelands in Iran. The combination of plant coverage and species richness rather than Shannon's diversity or species diversity (a latent variable of species richness and evenness) substantially enhance aboveground biomass across plant growth forms. In all selected SEMs, plant coverage had a strong positive direct effect on aboveground biomass (β = 0.72 for shrubs, 0.84 for forbs and 0.80 for grasses), followed by a positive effect of species richness (β = 0.26 for shrubs, 0.05 for forbs and 0.09 for grasses), and topographic factors. Disturbance intensity had a negative effect on plant coverage, whereas it had a variable effect on species richness across plant growth forms. Plant coverage had a strong positive total effect on aboveground biomass (β = 0.84 for shrubs, 0.88 for forbs, and 0.85 for grasses), followed by a positive effect of species richness, and a negative effect of disturbance intensity across plant growth forms. Our results shed light on the management of rangelands that is high plant coverage can significantly improve species richness and aboveground biomass across plant growth forms. We also found that high disturbance intensity due to heavy grazing has a strong negative effect on plant coverage rather than species richness in semi-steppe rangelands. This study suggests that proper grazing systems (e.g. rotational system) based on carrying capacity and stocking rate of a rangeland may be helpful for biodiversity conservation, better grazing of livestock, improvement of plant coverage and enhancement of aboveground biomass.

“I See the Grass Through the Mouths of My Animals” – Folk Indicators of Pasture Plants Used by Traditional Steppe Herders

Why is a type of rangeland grass called “the soul of the Hortobagy steppe” by a local herder deemed to be of low value by range scientists? In this paper I examine how herders see wild forage and fodder plants “through the mouths of the animals,” what kind of indicators they use, and how these indicators affect folk taxonomy. I focus on the Poaceae and Cyperaceae families (grasses, sedges, and their relatives), underrepresented taxa in ethnobiological studies. The Hortobagy is a salt steppe with low predictability of rain and pasture conditions. I conducted participatory field work and interviews with 92 herders. Herders have a special term for the consumable biomass of a pasture/meadow, “mező.” They distinguished between 28 types of hay and 30 types of mező and listed 34 plant folk taxa as important forage or fodder. I documented 13 different grazing-related indicators (plant traits), including nutritional value, interannual variation, and resprouting ability. The seasonal change in grazing value was a k...

Effects of climate change and adaptation on the livestock component of mixed farming systems: A modelling study from semi-arid Zimbabwe

Large uncertainties about the impacts of climate change and adaptation options on the livestock component of heterogeneous African farming systems hamper tailored decision making towards climate-smart agriculture. This study addressed this knowledge gap through the development and use of a dynamic modelling framework integrating climate, crop, pasture and livestock models. The framework was applied to a population of 91 farms located in semi-arid Zimbabwe to assess effects on livestock production resulting from climate change and management interventions. Climate scenarios representing relative “cool-wet”, “hot-dry” and “middle” conditions by mid-century (2040–2070) for two representative concentration pathways were compared with the baseline climate. On-farm fodder resources and rangeland grass production were simulated with the crop model APSIM and the pasture model GRASP respectively. The simulated fodder availability was used in the livestock model LIVSIM to generate various production indicators including milk, offtake, mortality, manure, and net revenue. We investigated the effects of two adaptation packages targeting soil fertility management and crop diversification and quantified the sensitivity to climate change of both current and improved systems. Livestock productivity was constrained by dry-season feed gaps, which were particularly severe for crude protein and caused by the reliance on rangeland grazing and crop residues, both of low quality in the dry season. Effects on grass and stover production depended on the climate scenario and the crop, but year-to-year variation generally increased. Relative changes in livestock net revenue compared to the baseline climate varied from a 6% increase to a 43% decrease, and the proportion of farmers negatively affected varied from 20% to 100%, depending on the climate scenario. Adverse effects of climate change on average livestock production usually coincided with increased year-to-year variability and risk. Farms with larger stocking density faced more severe feed gaps and were more sensitive to climate change than less densely stocked farms. The first adaptation package resulted in increased stover production and a small increase in livestock productivity. The inclusion of grain and forage legumes with the second package increased milk productivity and net revenues more profoundly by 30%. This was attributed to the alleviation of dry-season feed gaps, which also reduced the sensitivity to climate change compared to the current system. Clearly, individual farms were affected differently by climate change and by improved farm management, illustrating that disaggregated impact assessments are needed to effectively inform decision making towards climate change adaptation.

Why non-native grasses pose a critical emerging threat to biodiversity conservation, habitat connectivity and agricultural production in multifunctional rural landscapes

ContextLandscape-scale conservation planning is key to the protection of biodiversity globally. Central to this approach is the development of multifunctional rural landscapes (MRLs) that maintain the viability of natural ecosystems and promote animal and plant dispersal alongside agricultural land uses.ObjectivesWe investigate evidence that non-native grasses (NNGs) in rangelands and other low-intensity agricultural systems pose a critical threat to landscape conservation initiatives in MRLs both in Australia and globally.MethodsWe first establish a simple socio-ecological model that classifies different rural landscape elements within typical MRLs based on their joint conservation and agro-economic value. We then quantify the impacts of eight Australian NNGs (Andropogon gayanus, Cenchrus ciliaris, Eragrostis curvula, Hyparrhenia hirta, Nassella neesiana, Nassella trichotoma, Phalaris aquatica and Urochloa mutica) on different landscape elements and then classify and describe the socio-ecological transformations that result at the MRL scale.ResultsOur data indicate that two broad classes of NNGs exist. The first reduces both conservation and agro-economic value (‘co-degrading’ species) of invaded landscapes, while the second improves agro-economic value at the expense of conservation value (‘trade-off’ species). Crucially, however, both classes cause hardening of the landscape matrix, agricultural intensification, reduced habitat connectivity, and the loss of multi-value land use types that are vital for landscape conservation.ConclusionsNNGs drive socio-ecological transformations that pose a growing threat to landscape-scale connectivity and conservation initiatives in Australia and globally. There is an urgent need for further research into the impacts of NNGs on habitat connectivity and biodiversity within multifunctional landscapes, and the socio-ecological goals that can be achieved when landscape transformation and degradation by these species is unavoidable.

Does season and grazing influence the δ13C and δ15N of C4 native grasses in semi-arid rangelands of the Pilbara region of NW Australia?

Much of the semi-arid, native rangelands Pilbara region of NW Australia is used for cattle production with the most productive grasslands for cattle grazing dominated by the C4 perennials grasses; Astrebla pectinata, Themeda triandra, and Eragrostis xerophila. In both grazed and ungrazed plots, we quantified the seasonal variation in the natural abundance of 13C and 15N of green foliage. We assigned the C4 pathway of individual species (NAD-ME vs. NADP-ME) on the basis of δ13C. Foliage δ13C varied with seasonal conditions that in turn dictated patterns of growth (and of photosynthate production), and possibly also with the ‘leakiness’ of the bundle sheath cells. However the significant differences present in grazed and ungrazed plots for Astrebla and Themeda, indicate that grazing may result in greater water use efficiency in these semi-arid rangelands. Seasonal patterns of δ15N were highly variable and exhibited little correlation with seasonal patterns of growth and periods of inorganic N uptake. While it is possible that N obtained from sources other than the simple uptake of inorganic N contributed to observed δ15N patterns, there is little additional evidence to support this hypothesis. There was no difference in δ15N between grazed and ungrazed treatments for any of these grasses.