Search results for "forage"

2015

Prey preference of top predators and energy flow across habitat boundaries are of fundamental importance for structure and function of aquatic and terrestrial ecosystems, as they may have strong effects on production, species diversity, and food-web stability. In lakes, littoral and pelagic food-web compartments are typically coupled and controlled by generalist fish top predators. However, the extent and determinants of such coupling remains a topical area of ecological research and is largely unknown in oligotrophic high-latitude lakes. We analyzed food-web structure and resource use by a generalist top predator, the Arctic charr Salvelinus alpinus (L.), in 17 oligotrophic subarctic lakes…

Technical Note: Comparison of Techniques for Evaluating the Relative Preference by Sheep Among Saltbush Clones

2004

This research compared 4 field methods of evaluating the relative preference by sheep of 28 clones of saltbush (Atriplex halimus L.). The methods were as follows. 1) Leaf dots (LD): 8 leaves per shrub were marked on the lower surface with a small dot using a water-resistant, nontoxic ink. 2) Twig marks (TM): 2 current-year twigs per shrub were marked with 3 lines using the same ink approximately in the middle of the basal, median, and apical thirds. 3) Branch length (BL): 2 branches per shrub were marked with ink at the base of the current year's growth. The twigs were measured from the marked point to the top, before and after sheep browsing. 4) Ocular estimation (OE): the percentage of th…

Evaluation of automatically steered agricultural vehicles

2008

The popularization of automatic guidance systems for off-road vehicles, especially in agricultural environments, has led to a sudden affluence of commercial solutions. As a consequence, end users are often overwhelmed by the spread of possibilities commercially available, on top of the confusion provoked by the guidance accuracy advertised by manufacturers. Therefore, there is a need for a methodology that objectively quantifies the level of performance of any auto-steering system, classifying different solutions according to their accuracy and reliability. This paper describes a method to evaluate the behavior of any automatically driven agricultural vehicle traveling along paths of any cu…

Influence of fish aggregating devices (FADs) on anti-predator behaviour within experimental mesocosms

2015

Commercial fishers have used fish aggregating devices throughout the Mediterranean Sea for over 40 years. These devices attract numerous predatory and forage species in both coastal and offshore environments. This study examined the influence of fish aggregating devices on schooling and aggregating behaviour by small forage fish in quasi-natural mesocosms. Anti-predator behaviour was evaluated for juvenile Caranx crysos under a variety of treatment conditions. Results suggest that, in the absence of physical structure, C. crysos first respond to a predatory threat by forming a school. When a physical structure is present, however, C. crysos show an occasional tendency to aggregate near the …

Contrasting structural complexity differentiate hunting strategy in an ambush apex predator.

2021

AbstractStructural complexity is known to influence prey behaviour, mortality and population structure, but the effects on predators have received less attention. We tested whether contrasting structural complexity in two newly colonised lakes (low structural complexity lake—LSC; high structural complexity—HSC) was associated with contrasting behaviour in an aquatic apex predator, Northern pike (Esox lucius; hereafter pike) present in the lakes. Behaviour of pike was studied with whole-lake acoustic telemetry tracking, supplemented by stable isotope analysis of pike prey utilization and survey fishing data on the prey fish community. Pike displayed increased activity, space use, individual …

The proanthocyanidin content as a tool to differentiate between Lotus tenuis and L. corniculatus individuals

2012

Abstract Lotus tenuis Wald et Kit and Lotus corniculatus L. are conspicuous elements of the agricultural landscape for cattle production. In South America, commercial L. tenuis stocks usually present contaminations with L. corniculatus, what brings about an important economical injure to the forage producers. A way to reduce or avoid loses is to assess the purity degree of L. tenuis seed lots before seeding. Methods so far described for the diagnosis of Lotus species when flowers are not available are lengthy, time consuming, need the implementation of sophisticated laboratories and are relatively expensive. It has been shown that Lotus species accumulate variable proanthocyanidins amounts,…

Effects of male removal on female foraging behavior in the Eurasian treecreeper

1997

In old, spruce-dominated forests of central Finland, Eurasian treecreepers Certhia familiaris divide their territories spatially during the breeding season. Females forage primarily on the upper parts of the tree trunks, while males use the lower parts of the tree trunks. In this study we removed males from eight territories in the early nestling period to see if the mate's absence would change the foraging patterns of the resident female. Widowed females foraged at lower heights, thus behaving more like paired males. These females also spent less time on each tree and on each foraging bout than did paired females. We conclude that male removal facilitated the change in a female's foraging …

Attitudine alla consociazione di diverse leguminose foraggere mediterranee.

2011

Forage mixture productivity and silage quality from a grass/legume intercrop in a semiarid Mediterranean environment

2023

In semiarid environments of the Mediterranean region, intercropping is a sustainable agricultural system of long standing. In this area, the pea (Pisum sativum L.) is one of the most commonly grown legume crops. Little information is available on the quality of silages to be obtained from forage mixtures of pea intercropped with cereals or annual grasses. In this study, two experiments were conducted over the course of two growing seasons in Sicily (Italy) with the aim to determine the biomass production of forage crop mixtures and assess, only in the second experiment, the silage quality of grass and legumes. Four cereals and one annual grass species were grown in pure stand and in mixture…

Mycotoxins presence in pre- and post-fermented silage from Tunisia

2020

Abstract Silage represents a major part of the feed ration for livestock, being a potential cause of mycotoxicosis as it can be contaminated with toxigenic fungi capable of producing mycotoxins in suitable environmental conditions. In the present work, the presence of natural mycotoxins in samples collected of silage from the main producing areas in Tunisia (Ariana, Bizerte, Beja and Jendouba) was assessed based on different plant material (oat, barley, triticale, artichoke, sulla or raygrass). Mycotoxins were evaluated during three periods in green forage (P1) and subsequently in ensiled products after 60 days (P2) and 100 days (P3) of fermentation. Samples were extracted by a QuEChERS pro…