Forage Availability Research Articles

Diet of Lesser Scaup Wintering on Lake Pontchartrain, Louisiana

AbstractThe lesser scaup Aythya affinis has been a species of conservation concern since continental breeding populations began declining in the 1980s. The causes of this decline are likely multifaceted, but cross-seasonal effects are believed to play a prominent role: females unable to acquire sufficient nutrient reserves during winter and spring migration have poor survival and breeding success. Understanding scaup diet composition and prey selection can help managers not only diagnose mechanisms underlying wintering scaup distributions, but may also help direct management actions to increase forage availability and quality. We evaluated the diet of 60 scaup collected from a major wintering site in Louisiana, Lake Pontchartrain. Scaup consumed almost entirely mollusks, especially targeting medium-sized (6–16 mm) common rangia clams Rangia cuneata, which were strongly selected relative to their availability. Eighty-two percent of scaup consumed dark false mussels Mytilopsis leucophaeata and 57% consumed dwarf surf clams Mulinia lateralis; both foods were selected by scaup, but were uncommon in benthic samples. On the other hand, small snails Texadina sphinctostoma, Probythinella protera were common in dredge samples but were either avoided or consumed in proportion to their availability. We conclude that medium-sized common rangia clams and dark false mussels are the most consumed foods for scaup wintering on Lake Pontchartrain, and hypothesize that annual variation in prey populations may be an important proximate driver of scaup abundance.

On-animal acoustic monitoring provides insight to ungulate foraging behavior

Abstract Foraging behavior underpins many ecological processes; however, robust assessments of this behavior for free-ranging animals are rare due to limitations to direct observations. We leveraged acoustic monitoring and GPS tracking to assess the factors influencing foraging behavior of mule deer (Odocoileus hemionus). We deployed custom-built acoustic collars with GPS radiocollars on mule deer to measure location-specific foraging. We quantified individual bites and steps taken by deer, and quantified two metrics of foraging behavior: the number of bites taken per step and the number of bites taken per unit time, which relate to foraging intensity and efficiency. We fit statistical models to these metrics to examine the individual, environmental, and anthropogenic factors influencing foraging. Deer in poorer body condition took more bites per step and per minute and foraged for longer irrespective of landscape properties. Other patterns varied seasonally with major changes in deer condition. In December, when deer were in better condition, they took fewer bites per step and more bites per minute. Deer also foraged more intensely and efficiently in areas of greater forage availability and greater movement costs. During March, when deer were in poorer condition, foraging was not influenced by landscape features. Anthropogenic factors weakly structured foraging behavior in December with no relationship in March. Most research on animal foraging is interpreted under the framework of optimal foraging theory. Departures from predictions developed under this framework provide insight to unrecognized factors influencing the evolution of foraging. Our results only conformed to our predictions when deer were in better condition and ecological conditions were declining, suggesting foraging strategies were state-dependent. These results advance our understanding of foraging patterns in wild animals and highlight novel observational approaches for studying animal behavior.

Marginal Costs and Likely Supply Elasticities for Pollination and Honey

AbstractWe report new estimates of beekeeper costs and revenues, which include major activities undertaken by beekeepers, including honey producers and pollinators. We use our cost estimates, recent government surveys and other United States Department of Agriculture information to characterize supply functions for (1) pollination services to crops that bloom in the late winter (dominated by almonds), (2) pollination services to crops that bloom in the spring and summer, and (3) honey produced in the United States. The positions and shapes of these supply functions are crucial to understanding how the honeybee industry will respond to changes in demand for pollination services and other market conditions, including shifts in honey demand, honey import supply, and forage availability affected by climate change.

Goat track networks facilitate efficiency in movement and foraging

Striking networks of livestock tracks have been observed in hilly rangelands throughout the world. They have strong spatial heterogeneity in micro-topography, vegetation, soil physical properties, and hydrological and bio-geochemical processes. We have limited knowledge of the structural characteristics of these networks and their implications to energy efficiency of foraging livestock and associated land use policies. The objectives were to quantify the structure of the goat track network and the pattern of use by goats, and explore the implications of the network structure to forage efficiency and the potential mechanisms for maintenance of the network. Fifteen sites of terracette landscapes on hilly rangelands of Loess Plateau were selected. The imagery of goat tracks at each site were processed to generate a graph of the network and analyzed to examine the network structural characteristics and the pattern of use by goats. The characteristics of the goat track network, with low track angles of parallel segments and high track angles of conjunctive segments, facilitate energy-efficient movement of foraging goats and enables goats to access forage in most of the non-track areas. The goats preferred using the track segments with lower track angles and smaller turn angles. The network structure facilitates the energy efficiency of movement and forage accessibility of the goats. The network is likely maintained by goats’ preferential use of the track segments with high efficiency, which may have significant implications to the recent policy to exclude grazing over expansive regions of hilly rangelands of Loess Plateau.

Optimising economic and environmental performances of sheep-meat farms does not fully fit with the meat industry demands

AbstractRuminant farming systems are questioned for their contribution to climate change and feed-food competition. Here, we analyse the economic and environmental performances of five sheep farming systems optimised in terms of ewe productivity and feeding costs. Systems are located in contrasting biogeographical areas along a gradient of decreasing agronomic potential from Ireland to the French Mediterranean rangelands. Applying a mechanistic model of flock and farm operation management to evaluate these five systems made it possible to highlight trade-offs between their economic performance under standardised economic conditions, environmental performances, and feed-food competition, but also discrepancies between sheep farm strategy and meat industry demands. Different management strategies resulted in ewe productivity ranging from 0.82 to 1.66 lambs ewe−1 year−1 between farming systems and concentrate use from 0 to 148 kg ewe−1 year −1. The two systems relying the most on grassland and rangelands show the best economic and environmental performances while minimising feed-food competition. This results from a good match between animal feed requirements and forage availability; these systems, however, generate a high seasonality of production that does not meet the industry demand for a regular meat supply throughout the year. The Irish system also follows a forage autonomy strategy, but with poorer environmental and economic performance due to intensification, higher price of land, and lower meat price. Both the accelerated reproduction system with three lambing periods in two years and the organic system generate a more regular lamb supply, but require a higher level of concentrate feed, which negatively affects performances. These results highlight for the first time that optimising economic and environmental performances at farm level does not fully fit with the meat industry demand for a regular lamb meat supply throughout the year and lamb conformation. Low-productivity but fully self-sufficient fodder livestock systems can achieve excellent economic performance, but require both specific skills and marketing adequacy.

Where to forage when afraid: Does perceived risk impair use of the foodscape?

The availability and quality of forage on the landscape constitute the foodscape within which animals make behavioral decisions to acquire food. Novel changes to the foodscape, such as human disturbance, can alter behavioral decisions that favor avoidance of perceived risk over food acquisition. Although behavioral changes and population declines often coincide with the introduction of human disturbance, the link(s) between behavior and population trajectory are difficult to elucidate. To identify a pathway by which human disturbance may affect ungulate populations, we tested the Behaviorally Mediated Forage‐Loss Hypothesis, wherein behavioral avoidance is predicted to reduce use of available forage adjacent to disturbance. We used GPS collar data collected from migratory mule deer (Odocoileus hemionus) to evaluate habitat selection, movement patterns, and time‐budgeting behavior in response to varying levels of forage availability and human disturbance in three different populations exposed to a gradient of energy development. Subsequently, we linked animal behavior with measured use of forage relative to human disturbance, forage availability, and quality. Mule deer avoided human disturbance at both home range and winter range scales, but showed negligible differences in vigilance rates at the site level. Use of the primary winter forage, sagebrush (Artemisia tridentata), increased as production of new annual growth increased but use decreased with proximity to disturbance. Consequently, avoidance of human disturbance prompted loss of otherwise available forage, resulting in indirect habitat loss that was 4.6‐times greater than direct habitat loss from roads, well pads, and other infrastructure. The multiplicative effects of indirect habitat loss, as mediated by behavior, impaired use of the foodscape by reducing the amount of available forage for mule deer, a consequence of which may be winter ranges that support fewer animals than they did before development.

Combined effects of simulated browsing, warming and nutrient addition on forage availability for migratory caribou in Nunavik, Canada

At high population size, migratory caribou (Rangifer tarandus) are regulated by forage abundance in their summer range. Climate warming likely affects forage availability by increasing productivity and advancing phenology of vegetation. Our objective was to investigate the combined effects of browsing and climate warming on the availability of dwarf birch (Betula glandulosa). We simulated direct (warming, with open-top chambers) and indirect (increased nutrient cycling) effects of climate warming in interaction with simulated browsing (leaf stripping) from 2009 to 2013 in Nunavik, Canada. We measured the effect of treatments on dwarf birch biomass and phenology. Moderate and heavy browsing reduced the estimated biomass of birch leaves by 14% and 34%, respectively. Fertilization did not increase the biomass of birch leaves, but increased the biomass of another forage, Poaceae. The warming treatment advanced the opening of birch leaves by 4 days (95% CI: [3, 6]) in 2011 and 7 [5, 8] days in 2013, the two years colder than average. The absence of significant phenological shifts in warmed plots during warmer springs suggests that established dwarf birches may have reached a threshold in a limiting resource, likely soil moisture, under which they cannot respond to further warming. Our results demonstrate that browsing can reduce forage biomass, but the variability in caribou populations could provide windows of opportunity for shrub growth.

196 Performance of landrace hair sheep lambs in a forage-based, semi-continuous production system

Abstract Developing a system of year-round lamb production can address issues of continuous supply and product uniformity. In this project, Barbados Blackbelly (BB) and St. Croix (STX) Landrace hair sheep were used to produce cohorts of lambs in 4 mo intervals. Lambs were born on pasture, weaned at approximately 9 weeks, and returned to pasture after a period of post-weaning transition in pens. Ram lambs were rendered short-scrotum at weaning and grazed with ewe lambs as a single group in a rotational grazing system using cool season perennial grasses, warm and cool season annual forages, hay, and soy hull supplementation based on season and forage availability. Lambs were removed as they reached 35–40 kg or 12 mo of age. Data from two lamb cohorts born in April (n = 45) and August (n = 39), respectively, were analyzed for the effect of breed and sex on BW and ADG at different production stages. Birth weights of the April and August cohorts were similar (3.36 kg), but pre-weaning ADG and weaning weights were higher (P < 0.001) in the April (400 g/d and 15.6 kg) than August cohort (304 g/d and 12.1 kg). In contrast, pasture ADG (to 9 mo of age) was higher (P < 0.001) in the August (114 g/d) than April (73 g/d) cohort. Pasture ADG was higher (P < 0.05) in STX (100 g/d) than BB (88 g/d), and higher males (106 g/d) than females (81 g/d). During joint grazing of the two cohorts (December through March) ADG was initially higher (P < 0.001) in the older April (76 g/d) than August (16 g/d) lambs, but similar as they transitioned to annual forage (310 g/d). Pasture ADG fluctuated greatly in relation to forage quality, and to a lesser degree with breed and sex, and 79% of April and 84% of August cohort lambs reached target weights as yearlings.

173 The effects of Fescue EMTTM Mineral Defense on stocker heifer growth while grazing tall fescue

Abstract Previous research demonstrates grazing tall fescue can decrease reproductive performance and weight gain in cattle. The objective of this study was to evaluate Fescue EMTTM Mineral Defense (Cargill Animal Nutrition, Minneapolis, MN) on summer weight gain in cattle grazing tall fescue pastures in SW Missouri. Heifers (n = 120; initial BW = 236 ± 2.5 kg) were stratified by weight to replicated tall fescue pastures to either a control mineral treatment or Fescue EMT™ Mineral Defense treatment. Forage availability was estimated weekly by ultrasonic sensor. Pasture samples were collected every 21 d and analyzed for ergovaline concentrations. Heifer weights and blood prolactin were measured throughout the trial. Average daily mineral consumption was calculated by mineral offered less residual. Data were analyzed on a pen-mean basis as a completely randomized design using JMP with 6 pens/ treatment and 10 heifers/pen. Prolactin was analyzed as Repeated Measures in JMP. Initial weights between treatments were not different (P > 0.05). Endophyte infection measured 75% or greater in all pastures. No differences were detected in pasture ergovaline (149 ± 19 µg/kg) or pasture availability (2,600 ± 150 kg/ha) between treatments (P > 0.20 at each sampling). Heifer ADG consuming Fescue EMT™ Mineral Defense compared to control mineral was greater at 0.28 kg versus 0.22 kg resulting in total gains of 21.8 kg versus 16.6 kg, respectively (P < 0.05). However, blood prolactin numerically decreased over time in both treatments. Results from this trial demonstrate a 31% improvement in weight gain for cattle consuming Fescue EMTTM Mineral Defense compared with cattle consuming a control mineral while grazing toxic tall fescue.

Effect of population density on diet composition and dietary niche breadth of guanaco (Lama guanicoe, Müller 1776) in northeastern Patagonian steppes

The optimal foraging theory postulates that as animal population density increases, the progressive decline in preferred forage availability results in changes in diet composition and widening of dietary niche breadth. For sedentary guanaco populations, some authors proposed a mechanism of population density limitation below the environmental carrying capacity, mediated through territoriality. Under the optimal foraging theory, increased density would lead to changes in guanaco diet selectivity and composition. Conversely, under the self-regulation hypothesis, guanacos would not affect preferred forage availability and no differences in guanaco diet would be expected. We tested these contrasting hypotheses by assessing both the differences in the proportion of grasses and shrubs present in guanaco diet and dietary niche breadth at three contrasting densities in northeastern Patagonian steppes. We did not find guanaco density effects on preferred forage availability, grass-shrub proportions in the diet and diet selectivity. Guanacos showed a mixed diet composed by plant species of both high and low nutritional quality independently of population density. The lack of changes in diet composition suggests that guanacos did not perceive a restriction in forage availability in terms of either biomass or nutritional content, regardless the observed increase in population density.

HABITAT CHARACTERISTICS AT CAPTURE LOCATIONS OF WHITE-TAILED DEER FAWNS IN THE NORTHERN GREAT PLAINS

Ungulate species select habitat types to increase foraging opportunities and avoid predation, and may disproportionately select high-quality habitat types relative to their abundance on the landscape. Identifying cover types that are associated with improved survival is important in one of the most anthropogenically modified landscapes in North America, the Northern Great Plains. Our objective was to assess if 8 habitat types (open water, developed, forest, shrub, grassland, cropland, wetland, and pasture) present in the buffered area surrounding capture locations for newborn White-tailed Deer (Odocoileus virginianus) fawns differed from the surrounding area by using data collected in 13 counties comprising 3 states in the Northern Great Plains region. We found that grasslands, developed areas, and shrubby areas were the most prevalent habitat types at fawn-capture locations, whereas cropland, pastures, forests, and open water were least prevalent. Although grasslands and shrubby areas were considered high-quality fawning habitat, developed areas generally were not, and the greater amount of developed habitat found at fawn-capture locations is likely evidence of an increased amount of hiding cover available to fawns and potentially limited habitat at more distant locations. Conversely, the high proportion of agriculture found at capture locations and the surrounding area likely maximizes forage availability, but also limits cover during some seasons. Conservation programs that incorporate diverse habitat types in areas where agriculture dominates the landscape will increase the amount of available hiding cover for fawns.

Linking forest management to moose population trends: The role of the nutritional landscape.

Forested lands in the western USA have undergone changes in management and condition that are resulting in a shift towards climax vegetation. These changes can influence the quality and quantity of forage for herbivores that rely on early-seral plants. To evaluate how management of forested landscapes might affect nutrition for Shiras moose (A. a. shirasi) at large spatial scales, we focused on shrubs and evaluated summer diet composition, forage availability, and forage quality across 21 population management units encompassing >36,000 km2 in northern Idaho, USA. We identified 17 shrub species in the diets of moose, 11 of which comprised the bulk of the diets. These forage shrubs varied markedly in both energy (mean digestible energy for leaves ranged from 9.62 to 12.89 kJ/g) and protein (mean digestible protein for leaves ranged from 1.73 to 7.90%). By adapting established field sampling methods and integrating recent advances in remote sensing analyses in a modeling framework, we predicted approximations of current and past (i.e., 1984) quantities of forage shrubs across northern Idaho. We also created a qualitative index of population trend for moose across population management units using harvest data. Predicted quantities of forage shrubs varied widely across the study area with generally higher values at more northern latitudes. The quantity of forage shrubs was estimated to have declined over the past 30 years in about half of the population management units, with the greatest declines predicted for high-energy forage species. The population trend index was correlated with the percent change in availability of moderate-energy forage shrubs, indicating that availability of forage shrubs and change in availability over time might be affecting population dynamics for moose in northern Idaho. Our study highlights the importance of assessing how changes in forest management across broad spatiotemporal extents could affect wildlife and their habitats.

Seasonal selection of key resources by cattle in a mixed savannah-wetland ecosystem increases the potential for conflict with lions

In Africa's pastoral conservation landscapes, apex predators frequently kill livestock. Retaliatory persecution such as poisoning threatens predators, but also non-target biota. Several factors influence conflict severity, including livestock husbandry, overlap in seasonal habitat use, and the degree to which livestock perceive and are able to respond to a landscape of fear. We investigated these factors by GPS-tracking 42 Tswana beef cattle (Bos taurus) from 29 herds in 2017 and six lions (Panthera leo) from different prides (May 2016–Dec. 2017) in the northern Okavango Delta, Botswana, where cattle depredation significantly impacts the livelihoods of rural agro-pastoralists. Cattle exhibited seasonal habitat selection patterns similar to wild ungulates in the region. They preferred woodland habitats, with more digestible grasses, during the wet season. During the dry season, they preferred wetland habitats with reliable forage and water availability. Cattle also preferred areas close to human settlements, but the necessity to forage in wetlands during the dry season exposed them to significant depredation risk, especially >4 km from settlements. Lions killed most cattle in wetlands during the late dry season but the intensity of recent lion presence (previous 14 days) only had a weak negative effect on cattle habitat selection patterns. Cattle used rangelands according to nutritional requirements, irrelevant of the associated predation risk, suggesting that socio-ecologically acceptable conflict solutions cannot rely on the exclusion of livestock from seasonal wetlands. Curbing depredation by lions will best be achieved by a combination of resource- and predation-cognisant seasonal herding strategies with adequate livestock protection. Understanding the ecological constraints that intensify conflict is pertinent to any livestock production landscape with predator presence. It is also a central prerequisite for future land use planning and devolution of legal, controlled resource access rights through policy. Coexistence strategies must account for the strong reliance of people, their livestock, and wildlife on shared key resources. This is particularly important in large trans-frontier conservation areas where the successful merging of biodiversity conservation and rural development is a strategic goal. Omission will foster resentment and resistance to coexistence with apex predators, particularly if livestock productivity and human livelihoods are negatively affected.

Hepatic transcriptome profile of sheep (Ovis aries) in response to overgrazing: novel genes and pathways revealed

BackgroundOvergrazing is a major factor that causes steppe degradation in Inner Mongolian, resulting in extensive ecosystem damage. Scarcity of grass means sheep are smaller and therefore mutton and cashmere production is greatly reduced, which has resulted in massive annual economic losses. Liver is the primary metabolic organ in mammals. It is also the key source of energy supply and detoxification of metabolites in animals, has a close relationship with animal growth. However, investigations on the responses of sheep induced by consequence of overgrazing, particularly those relating to liver-related molecular mechanisms and related metabolic pathways, remain elusive.ResultsThe body weight daily gain of sheep, immune organ indices (liver and spleen), and serum parameters related to immune response, protein synthesis and energy supply (IgG, albumin, glucose and non-esterified fatty acid) were significantly lower in the overgrazing group. Other serum parameters including alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, total bilirubin, blood urea nitrogen and interleukin-6 were significantly higher in the overgrazing group. For the RNA-Seq results, we identified approximately 50 differentially expressed genes, of which half of were up-regulated and the other half were down-regulated (overgrazing group versus light grazing group). Bioinformatics analysis identified two enriched KEGG pathways including peroxisome proliferator-activated receptor (PPAR) signaling pathway (related to lipolysis) and ECM-receptor interaction (related to liver injury and apoptosis). Additionally, several of the down-regulated genes were related to detoxification and immune response.ConclusionsOverall, based on the high-throughput RNA sequencing profile integrated with the results of serum biochemical analyses, consequences of lower forage availability and quality under overgrazing condition induced altered expression levels of genes participating in energy metabolism (particularly lipid metabolism) and detoxification and immune responses, causing lipolysis and impaired health status, which might be key reasons for the reduced growth performance of sheep. This investigation provides a novel foundation for the development of sheep hepatic gene interactive networks that are a response to the degraded forage availability under overgrazing condition.

Public–Private Partnership Wetland Restorations Provide Quality Forage for Waterfowl in Northern New York

Abstract The Partners for Fish and Wildlife Program and Wetlands Reserve Program are U.S. federal programs that provide financial and technical assistance to restore wetland habitats on private property, and are important tools for the conservation and management of waterfowl. This study examined whether these wetland restorations successfully restored one important component of waterfowl habitat, the availability of vegetative forage, at sites in the St. Lawrence River valley of New York. We conducted surveys at 47 restored and 18 reference wetlands to characterize the vegetation assemblage in terms of its value as forage for waterfowl. Results suggest that these public–private partnership wetland restorations develop assemblages of wetland vegetation that are similar to reference wetlands. Vegetation assemblage metrics, including estimates of species richness, the richness of species of food value, the Vegetative Forage Quality Index, and the cover of species of food value, did not differ between restored–reference wetland pairs. However, invasive species were common at sites, and we detected a negative association between the cover of invasive species and the Vegetative Forage Quality Index at both restored and reference wetlands. On the basis of these results, we conclude that Partners for Fish and Wildlife Program and Wetland Reserve Program wetland restorations provide quality forage for breeding and migratory waterfowl in this region, but that the presence of invasive vegetation at sites has the potential to decrease the quality of vegetative forage at sites over time.

Carnivore space use shifts in response to seasonal resource availability

AbstractEstimating spatial and temporal resource use and partitioning among carnivore species varies based on life history and is critical to understanding ecological relationships of sympatric carnivores and their prey. Temporal variation in food availability can have a substantial influence on distribution, foraging behavior, prey selection, and population dynamics of carnivores. We investigated shifts in space use of black bears (Ursus americanus), bobcats (Lynx rufus), coyotes (Canis latrans), and gray wolves (C. lupus) in response to seasonal availability of white‐tailed deer (Odocoileus virginianus) fawns in Michigan,USA, May–August 2009–2011. We used generalized linear mixed models to identify whether probabilistic fawn space use resulted in shifts in carnivore space use from deer pre‐parturition (PPP, 1 May–24 May) to fawn limited mobility (LMP, 25 May–30 June) and social mobility (SMP, 1 July–31 August) periods. We developed a rule‐based algorithm to identify “clusters” of carnivoreGPSlocations and investigated carnivore clusters to identify fawn predation sites. Carnivores shifted space use among periods, but responses varied among species regarding fawn space use. Black bears selected against areas with greater fawn use duringLMPand selected areas with greater fawn use duringSMP. We suggest black bear space use was unrelated to fawn space use and reflected availability of vegetative forage. Bobcats selected areas with greater fawn use duringLMPandSMP. Coyotes were indifferent to areas where fawns occurred duringLMPbut selected against areas with greater fawn use duringSMP, likely foraging on alternative prey. Coyotes were spatially constrained by wolves, selecting against areas with greater wolf use duringLMPandSMP. Wolves selected against areas with greater fawn use duringLMPandSMPand selected areas near habitat edges and areas containing livestock carcasses. Carnivore responses to fawn white‐tailed deer distribution and vulnerability were congruent with life history strategies, resulting in space use shifts in response to temporarily abundant resources. Carnivores did not overall rely predominantly on fawns, likely shifting their space use to maximize intake of other seasonal resources. These events provide additional insight into life history strategies among co‐occurring species and dynamics of multi‐species predator–prey systems.

The onset in spring and the end in autumn of the thermal and vegetative growing season affect calving time and reproductive success in reindeer.

A developing trophic mismatch between the peak of energy demands by reproducing animals and the peak of forage availability has caused many species’ reproductive success to decrease. The match–mismatch hypothesis (MMH) is an appealing concept that can be used to assess such fitness consequences. However, concerns have been raised on applying the MMH on capital breeders such as reindeer because the reliance on maternal capita rather than dietary income may mitigate negative effects of changing phenologies. Using a long-term dataset of reindeer calving dates recorded since 1970 in a semidomesticated reindeer population in Finnish Lapland and proxies of plant phenology; we tested the main hypothesis that the time lag between calving date and the plant phenology in autumn when females store nutrient reserves to finance reproduction would lead to consequences on reproductive success, as the time lag with spring conditions would. As predicted, the reproductive success of females of the Kutuharju reindeer population was affected by both the onset of spring green-up and vegetative senescence in autumn as calves were born heavier and with a higher first-summer survival when the onset of the vegetation growth was earlier and the end of the thermal growing season the previous year was earlier as well. Our results demonstrated that longer plant growing seasons might be detrimental to reindeer’s reproductive success if a later end is accompanied by a reduced abundance of mushrooms.

Kinetics of gas production of fodder of Moringa oleifera Lam grown in tropical dry forest areas from Colombia

Moringa oleifera is considered as an alternative to improve the availability and quality of forage for feeding ruminants in tropical areas. Nutritional quality and gas production were evaluated analyzing the fodder of cultivars of M. oleifera from different Colombian provenances. Samples of leaves and thin stems were taken during the dry season from three cultivars (Flandes, Armero and Palmira). Bromatological analysis was determined in the laboratory of Animal Nutrition at the National University of Colombia—Palmira; gas production kinetics was determined using the syringes test during 72 h. Values obtained were used to run a Gompertz model building kinetic curves of gas production. To compare the mean test Tukey HSD (P < 0.05) was applied. Results suggest acceptable fiber contents: FDN (35.67, 41.99, 27.45%); FDA (22.28, 24.98, 15.04%); LDA (4.04, 4.95, 2.50%), respectively. The time to inflection point (HIP, hours) was 134 for Flandes, 24.01 for Amero and 19.34 for Palmira; Flandes’ HIP indicates that the test should be longer than 72 h to confirm this value. The volume of gas at inflection point (GIP, ml) was very similar for the three accessions (61.27; 78.80 and 69.98 for Flandes, Amero and Palmira respectively). The highest maximum gas production rate (MRGP, ml/h) found was 10.1 for Armero cultivar. Lower Lag phase (LPh or microbial establishment, h) was 12.12 h in Palmira. Our conclusion is that the bromatological quality of M. oleifera and gas production differs in fodder of different origins, probably caused by differences in management and soil conditions.

Seeding rate effects on yield components and forage quality of Agaitti Berseem-2002 – an improved variety of berseem clover

ABSTRACTThe poor availability and high cost of quality forage seed provide a major limitation to the productivity of resource-poor dairy farmers in Pakistan. The cost can be minimized if such seeding rates are used to provide optimal forage and seed yields. A field experiment was therefore conducted to investigate the effect of different seeding rates (10, 15, 20, and 25 kg/ha) of Agaitti Berseem-2002 on forage and seed yield components, and forage quality. The results revealed that the seeding rate significantly (P < 0.05) affected number of seeds/m2, seed weight, seed yield and acid detergent fiber (ADF). However, seed rate effects on all the remaining forage and seed yield traits, and quality parameters were found to be non-significant (P > 0.05). The highest value for number of heads/m2 (471) was achieved at a seeding rate of 25 kg/ha, whereas the highest thousand seed weight (3.99 g) and estimated seed yield (687 kg/ha) were obtained at 20 kg/ha, and ADF of forage (20%) was found at a seeding rate of 15 kg/ha. The lowest values for number of heads/m2 (287), seed weight (3.33 g) and estimated seed yield (328 kg/ha) were recorded at a seeding rate of 10 kg/ha. There was no significant difference found between 15 and 20 kg/ha seeding rates in relation to forage yield and quality parameters. Therefore, a seeding rate of 10 kg/ha is recommended to attain the highest forage yield of better quality, whereas a seeding rate of 20 kg/ha provided higher seed production than 10, 15, and 25 kg/ha.

Using seasonal landscape models to predict space use and migratory patterns of an arctic ungulate

BackgroundCaribou in the Western Arctic Herd undertake one of the longest, remaining intact migrations of terrestrial mammals in the world. They are also the most important subsistence resource for many northern rural residents, who rely on the caribou’s migratory movements to bring them near for harvest. Migratory geography has never been static, but subsistence harvesters have reported recent shifts in migration away from areas where they traditionally occurred. The reasons behind these changes are not well-understood, but may be related to rapid climate change and anthropogenic disturbances.MethodsTo predict changes in distribution and shifting migratory areas over the past decade, we used GPS telemetry data from adult females to develop predictive ecological niche models of caribou across northwestern Alaska. We employed the machine-learning algorithm, TreeNet, to analyze interactive, multivariate relationships between telemetry locations and 37 spatial environmental layers and to predict the distributions of caribou during spring, calving season, insect-harassment season, late summer, fall, and winter from 2009 to 2017. Model results were analyzed to identify regions of repeated predicted use, quantify mean longitude, predict land cover selection, and track migratory changes over time.ResultsDistribution models accurately predicted caribou at a spatially-explicit, 500-m scale. Model analyses identified migratory areas that shifted annually across the region, but which predicted 4 main areas of repeated use. Niche models were defined largely by non-linear relationships with coastally-influenced, climatic variables, especially snow-free date, potential evapo-transpiration, growing season length, proximity to sea ice, winter precipitation and fall temperature. Proximity to roads and communities were also important and we predicted caribou to generally occur more than 20–100 km from these features.ConclusionsWestern Arctic Herd caribou were predicted to occur in warmer, snow-free and treeless areas that may provide conditions conducive for efficient travel and foraging. Rapidly changing seasonal climates and coastal influences that determine forage availability, and human impediments that slow or divert movements are related to geographically and phenologically dynamic migration patterns that may periodically shift caribou away from traditional harvest areas. An enhanced understanding of the geographic behavior of caribou over time could inform traditional harvests and help conserve important Western Arctic caribou migratory areas.