Trends of Aboveground Net Primary Productivity of Patagonian Meadows, the Omitted Ecosystem in Desertification Studies

The United Nations defines desertification as the loss of productivity in arid and semiarid environments. The extended steppes of Patagonia harbor small meadows whose compounded area is comparatively small, but their aboveground net primary production (ANPP) is up to ten times higher than their surroundings. These meadows then represent a key ecosystem for cattle grazing systems, but there are no descriptions of the trends in their ANPP and, consequently, their carrying capacity, and, as a result, their degradation syndromes. Our objectives were as follows: (1) analyze the trends of mean and spatial heterogeneity of annual ANPP in meadows and neighboring steppes and relate them with precipitation and temperature, (2) evaluate the impact on the livestock carrying capacity of meadows in the region, and (3) evaluate the degradation trends of these meadows, based on a novel description proposed to characterize the trend syndromes of these type of ecosystems. We identified meadow areas across a subcontinental scale in Patagonia, covering a mean annual precipitation range from 129 to 936 mm. We estimated ANPP on a monthly basis from 2000 to 2019 via regional calibrated remote sensing information. In the last two decades, ANPP decreased in 74% of the studied meadow areas, while remaining relatively stable in the nearby steppes. This decrease was relatively higher in the arid end of the analyzed precipitation gradient. Hence, the global carrying capacity for all the studied meadow areas decreased by 8%. Finally, we identified four trend syndromes based on the combination of the ANPP trend and its spatial heterogeneity, calculated as the spatial standard deviation. The predominant trend syndrome, in 55% of the area, was associated with a negative trend of both ANPP and spatial heterogeneity. These results could help prioritize areas where specific management decisions, given the different trend syndromes, could help revert ANPP negative trends

Winter Herbage Mass Accumulation and Animals Grazing Days of Set Stocking or Cell Grazing Dairy x Beef Systems in Southwest England

Cell grazing (CG) has shown to increase the production per hectare by allowing higher stocking rates, greater grass production and higher herbage utilisation throughout the grazing season compared to set stocking (SS). Our objective was to compare the herbage growth rate during winter resting (WHGR, October/November to April) and the animals grazing days per ha (AGD-ha) of CG and SS systems grazed by dairy x beef steers. Three 1.75ha (1.5ha in 2018) plots and three 1.0ha were used for the SS and CG, respectively. Forty-two and 48 autumn born dairy x beef steer calves were split into six equal groups and randomly allocated to treatments in April 2018 and April 2020, respectively. In the second grazing seasons (2019 and 2021), the number of animals was reduced to keep stocking rates comparative to the prior year, and steers remained in the plots until finishing (October/November). Herbage mass (HM) was recorded weekly with a rising plate meter. The WHGR was estimated by subtracting the HM recorded at the end of the previous grazing season to the HM recorded at the beginning of the following season and divided by the number of days between readings. The AGD-ha was calculated by summing the days each animal grazed each area and divided by the size of the study enclosure. In three of the four years, the CG had fewer days of winter resting (157-175) than the SS (157-182), whereas the WHGR was greater in three of the four winters (average across years: 5.77 vs. 4.05 kg DM/ha per d, for CG and SS respectively). Despite the shorter winter rest, overall, the CG accumulated 37% more HM (average across years: 976 vs. 710 kg DM/ha) and had 78% more AGD-ha (1102 vs. 620 animal.d/ha) than SS. These differences do not seem to be driven by the herbage residual at the end of the grazing season but by the change in botanical composition across time

Comparing Forage Biomass Estimation Between Forager-Mounted Near Infrared Spectroscopy (NIRS) and Rising Plate-Meter (RPM) Techniques

Quantifying the forage mass harvested per paddock is essential for informing late-season management decisions on grazing livestock farms. This information can be used to calculate winter feed budgets and thus support decisions such as area of land to defer for autumn grazing, and head of stock to sell before winter housing. However, there are practical limitations associated with existing measurement methods, which can influence the accuracy of forage biomass estimates. The purpose of the current study was therefore to compare biomass estimation from two alternative precision farming methods — near infrared spectroscopy (NIRS) integrated within-spout of a self-propelled forage harvester, against a rising plate meter (RPM). Data were collected from the North Wyke Farm Platform (NWFP) in South- West England. RPM readings were taken within seven days preceding harvest, and Harvester measurements taken at the point of harvest. Data from two paddocks were collected during 2021 (figure 2, points a and b) and two from 2020 (points c and d). Three of the sampled paddocks (a, c and d) contained permanent pasture and one (b) contained reseeded white clover and perennial ryegrass. Paddocks c and d in figure 2 suggest a good correspondence between methods, demonstrated by proximity to the 1:1 line which passes through the origin. However, points a and b lie parallel to the 1:1 line, suggesting a systematic underestimation from the RPM. This underestimation could be linked to the tendency of grass to lodge at high yields, or due to an unquantified factor linked to the year of harvest, such as weather conditions which are known to indirectly influence RPM readings. With suitable calibration and consideration of practical limitations, forager mounted NIRS technology can provide valuable farm management data quickly, and at a relatively low cost compared to manual methods of biomass estimation

Biophysical, Grazing-Season Management, and Animal Traits Effects on Individual Animal Performance of Cow-Calf Systems: Insights from a Long-Term Experiment in the US Western Great Plains

Beef grazing systems require information on management, biophysical, and individual animal influences on performance metrics. However, long-term controlled experiments are lacking to comprehensively ascertain these individual and likely interacting influences. We used a legacy data set from the USDA Agricultural Research Service where individual weight gains were determined from on and off weights of Hereford cows and calves grazing native northern mixed-grass prairie, during the June through September season, from 1975-2001 near Cheyenne, Wyoming, USA. The herd size varied from a minimum of 10 to a maximum of 48 pairs across years. Management (on and off grazing dates and stocking rate, kg BW/ha), biophysical (forage production estimated through NDVI LANDSAT time series, temperature, and precipitation variability), and individual animal (cow age, cow body weight at beginning of grazing season, and calf gender) influences were evaluated for effects on calf weight gain (WG, kg/head). Linear mixed models were used for analyses where the above mentioned were fixed factors, and year and individual cow were random ones. Calf performance was influenced by three animal traits: gender with steer WG 4 kg more than heifer, cow body weight with calf WG increased 2kg for each 100kg of cow body weight, and cow age as optimum calf WG occurred with 5-year-old cows. Management influenced calf WG through the on and off dates. Delaying the start of a grazing season decreased calf WG by 0.80 kg per delayed day. On the contrary, extending the grazing season increased calf WG by about the same amount. Biophysical effects on calf WG were not significant suggesting that the cow performance was mitigating these effects of variability. Results suggest that calf individual performance in this resilient rangeland ecosystem relies on cows’ body weight at beginning of the grazing, their age, and the timing to enter and remove animals from pastures

Physical activity and self-rerceived health among people aged 50 and over

El propósito del estudio es analizar los posibles efectos de la actividad física sobre la salud autopercibida. Para ello, se encuestó a 765 personas entre 50-70 años durante 2012 en España. Se utilizó el cuestionario internacional de actividad física (IPAQ) para estimar el equivalente metabólico de la tarea (MET) total y en cuatro ámbitos: trabajo, ocio, hogar y desplazamientos. La salud autopercibida se obtuvo de la escala visual analógica del EQ-5D-5L. Los resultados muestran que únicamente el gasto energético de actividad física en el tiempo de ocio incide positivamente en el nivel de salud percibido, el resto de ámbitos no tienen influencia significativa. Asimismo, la autopercepción de la salud es más negativa con mayor edad, menor nivel educativo y mayor frecuencia de uso de servicios sanitarios. En conclusión, la actividad física desarrollada en el tiempo libre podría plantearse como alternativa para mejorar la calidad de vida de los mayoresThe purpose of the study was to analyse possible related effects between exercise and self-perceived health among people over 50 years old. A survey was conducted in 2012 to 765 community-living subjects from Spain aged between 50 and 70 years. The survey includes the long version of the International Physical Activity Questionnaire (IPAQ) to estimate total physical activity/week in METS (Measure Activity in Metabolic Equivalents) and in four different domains: work, leisure, transport and domestic/gardening. Selfperceived health was measured using the Visual Analogic Scale of the EQ-5D- 5L. The results of the study show that only the level of physical activity developed in leisure time has a positive and statistically significant effect on self-perceived health, whilst the other domains of physical activity are non-significant. Additionally, age, lower educational level and a higher use of health-care services are negatively associated with self-perceived health. To sum up, leisure time physical activity could be an alternative to increase the quality of life of older peopl

Using APAR to Predict Aboveground Plant Productivity in Semi-Arid Rangelands: Spatial and Temporal Relationships Differ

Monitoring of aboveground net primary production (ANPP) is critical for effective management of rangeland ecosystems but is problematic due to the vast extent of rangelands globally, and the high costs of ground-based measurements. Remote sensing of absorbed photosynthetically active radiation (APAR) can be used to predict ANPP, potentially offering an alternative means of quantifying ANPP at both high temporal and spatial resolution across broad spatial extents. The relationship between ANPP and APAR has often been quantified based on either spatial variation across a broad region or temporal variation at a location over time, but rarely both. Here we assess: (i) if the relationship between ANPP and APAR is consistent when evaluated across time and space; (ii) potential factors driving differences between temporal versus spatial models, and (iii) the magnitude of potential errors relating to space for time transformations in quantifying productivity. Using two complimentary ANPP datasets and remotely sensed data derived from MODIS and a Landsat/MODIS fusion data product, we find that slopes of spatial models are generally greater than slopes of temporal models. The abundance of plant species with different structural attributes, specifically the abundance of C4 shortgrasses with prostrate canopies versus taller, more productive C3 species with more vertically complex canopies, tended to vary more dramatically in space than over time. This difference in spatial versus temporal variation in these key plant functional groups appears to be the primary driver of differences in slopes among regression models. While the individual models revealed strong relationships between ANPP to APAR, the use of temporal models to predict variation in space (or vice versa) can increase error in remotely sensed predictions of ANPPEEA Concepción del UruguayFil: Gaffney, Rowan. United States Department of Agriculture–Agricultural Research Service. Rangeland Resources and Systems Research Unit; Estados UnidosFil: Porensky, Lauren M. United States Department of Agriculture–Agricultural Research Service. Rangeland Resources and Systems Research Unit; Estados UnidosFil: Feng, Gao. United States Department of Agriculture–Agricultural Research Service. Hydrology and Remote Sensing Laboratory; Estados UnidosFil: Irisarri, Jorge Gonzalo Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; ArgentinaFil: Durante, Martin. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Concepción del Uruguay; ArgentinaFil: Derner, Justin D. United States Department of Agriculture-Agricultural Research Service. Rangeland Resources Research Unit; Estados UnidosFil: Augustine, David J.. United States Department of Agriculture–Agricultural Research Service. Rangeland Resources and Systems Research Unit; Estados Unido

Historical isolation facilitates species radiation by sexual selection: Insights from Chorthippus grasshoppers

Theoretical and empirical studies have shown that species radiations are facilitated when a trait under divergent natural selection is also involved in sexual selection. It is yet unclear how quick and effective radiations are where assortative mating is unrelated to the ecological environment and primarily results from sexual selection. We address this question using sympatric grasshopper species of the genus Chorthippus, which have evolved strong behavioural isolation while lacking noticeable ecomorphological divergence. Mitochondrial genomes suggest that the radiation is relatively recent, dating to the mid‐Pleistocene, which leads to extensive incomplete lineage sorting throughout the mitochondrial and nuclear genomes. Nuclear data shows that hybrids are absent in sympatric localities but that all species have experienced gene flow, confirming that reproductive isolation is strong but remains incomplete. Demographic modelling is most consistent with a long period of geographic isolation, followed by secondary contact and extensive introgression. Such initial periods of geographic isolation might facilitate the association between male signaling and female preference, permitting the coexistence of sympatric species that are genetically, morphologically, and ecologically similar, but otherwise behave mostly as good biological species

Geographic Variation in Festuca rubra L. Ploidy Levels and Systemic Fungal Endophyte Frequencies

Polyploidy and symbiotic Epichloe fungal endophytes are common and heritable characteristics that can facilitate environmental range expansion in grasses. Here we examined geographic patterns of polyploidy and the frequency of fungal endophyte colonized plants in 29 Festuca rubra L. populations from eight geographic sites across latitudes from Spain to northernmost Finland and Greenland. Ploidy seemed to be positively and negatively correlated with latitude and productivity, respectively. However, the correlations were nonlinear; 84% of the plants were hexaploids (2n = 6x = 42), and the positive correlation between ploidy level and latitude is the result of only four populations skewing the data. In the southern-most end of the gradient 86% of the plants were tetraploids (2n = 4x = 28), whereas in the northernmost end of the gradient one population had only octoploid plants (2n = 8x = 56). Endophytes were detected in 22 out of the 29 populations. Endophyte frequencies varied among geographic sites, and populations and habitats within geographic sites irrespective of ploidy, latitude or productivity. The highest overall endophyte frequencies were found in the southernmost end of the gradient, Spain, where 69% of plants harbored endophytes. In northern Finland, endophytes were detected in 30% of grasses but endophyte frequencies varied among populations from 0% to 75%, being higher in meadows compared to riverbanks. The endophytes were detected in 36%, 30% and 27% of the plants in Faroe Islands, Iceland and Switzerland, respectively. Practically all examined plants collected from southern Finland and Greenland were endophyte-free, whereas in other geographic sites endophyte frequencies were highly variable among populations. Common to all populations with high endophyte frequencies is heavy vertebrate grazing. We propose that the detected endophyte frequencies and ploidy levels mirror past distribution history of F. rubra after the last glaciation period, and local adaptations to past or prevailing selection forces such as vertebrate grazing