The prey of the strongest /

Mode of access: Internet.

California fruit and nut crops: acreage, production, utilization and value, 1949-1961; bloom, harvesting and marketing dates and principal producing counties.

Revises and updates California. Dept. of Agriculture. State publication 261.

Water harvesting by catchments /

Mode of access: Internet.

THE HARVESTING AND OTHER POEMS.

Mode of access: Internet.

Harvesting wheat with a combined harvester-thresher in the Great Plains region, 1926. By R. S. Kifer, W. R. Humphries [and] J. H. Martin. A preliminary report. April, 1927.

Caption-title.

Low-cutting devices for harvesting corn /

"August, 1929."

Harvesting Wheat

Saline Valley Farms was an experiment in cooperative farming and living begun in 1932 by Harold S. Gray.

Harvesting Oats

Saline Valley Farms was an experiment in cooperative farming and living begun in 1932 by Harold S. Gray.

Life histories of North American birds of prey; order Falconiformes,

Bibliography: v.1, p. 381-398; v.2, p. 445-466.

A brief discussion of the history of cotton, its culture, breeding, harvesting and uses.

Mode of access: Internet.

Merit, red rock, and potomac : tomato varieties adapted to mechanical harvesting /

Mode of access: Internet.

An evolutionary economic perspective on technical change and adjustment in cane harvesting systems in the Australian sugar industry

Australian sugar-producing regions have differed in terms of the extent and rate of incorporation of new technology into harvesting systems. The Mackay sugar industry has lagged behind most other sugar-producing regions in this regard. The reasons for this are addressed by invoking an evolutionary economics perspective. The development of harvesting systems, and the role of technology in shaping them, is mapped and interpreted using the concept of path dependency. Key events in the evolution of harvesting systems are identified, which show how the past has shaped the regional development of harvesting systems. From an evolutionary economics perspective, the outcomes observed are the end result of a specific history.

Do harvest refuges buffer kangaroos against evolutionary responses to selective harvesting?

There is a wealth of literature documenting a directional change of body size in heavily harvested populations. Most of this work concentrates on aquatic systems, but terrestrial populations are equally at risk. This paper explores the capacity of harvest refuges to counteract potential effects of size-selective harvesting on the allele frequency,of populations. We constructed a stochastic, individual-based model parameterized with data on red kangaroos. Because we do not know which part of individual growth would change in the course of natural selection, we explored the effects of two alternative models of individual growth in which alleles affect either the growth rate or the maximum size. The model results show that size-selective harvesting can result in significantly smaller kangaroos for a given age when the entire population is subject to harvesting. In contrast, in scenarios that include dispersal from harvest refuges, the initial allele frequency remains virtually unchanged.

Genetic effects of kangaroo harvesting

There is concern that the commercial harvest of kangaroos (Macropus spp.) is affecting species fitness and evolutionary potential because the harvest selects for larger individuals, particularly males. This paper reviews the likely effect of selective harvesting on specific traits associated with fitness, including size, and on adaptive genotypes through generalised loss of gene diversity. Heritability for traits associated with fitness is low generally. The intensity of selection imposed by harvesting is low for several reasons: the geographic size of genetic populations is much larger than the harvest localities, which are therefore not closed but open with immigration acting to correct any change in allele frequencies through harvesting; the harvest targets kangaroos above a threshold weight that includes all adult males, not the largest males specifically; larger, older males may not confer significant fitness benefits on offspring; fitness traits are inherited through both sexes while males are targeted predominantly; populations are not at a selective equilibrium because food availability fluctuates, and the fittest is unlikely to be the largest. Comparisons of harvested and unharvested populations do not show any loss of gene diversity as a result of harvesting. The likelihood of a long-term genetic impact of kangaroo harvesting as currently practiced is negligible.