Seasonal changes in mass and reproductive condition of the corn mouse (Calomys musculinus) on the Argentine pampa

Article Abstract:

Samples of Calomys musculinus were captured in the pampa of central Argentina. A large proportion of C. musculinus captured during the winter are of low body mass. The lighter mice are not young; the low body mass is due to low temperatures and scarcity of resources. C. musculinus living in seasonal regions exhibit seasonal variation in growth rates and reproduction. The male reproductive system is more sensitive to the harsh conditions of winter. Body mass is more important than age in determining reproductive status. External conditions of genitalia are shown by histological studies to be an inaccurate predictor of breeding activity.

Argentina, Natural history, Mice, Mice (Rodents), Body weight, Reproduction (Biology), Animal anatomy, Reproduction, Seasonal variations (Biology)

---

Species diversity gradients: we know more and less than we thought

Article Abstract:

The tropics contain the most number of species, and diversity declines away from the tropics. The large regions of the tropics stimulate speciation and inhibit extinction. The latitudinal gradients depend on the evolutionary timescale, which in turn determines species diversity. Habitat diversity is a coevolved property of the species in a biome. The latitudinal diversity gradient is not a species-area curve because such curve is a function of habitat diversity. As productivity rises within a region, first diversity rises and then it falls. Poor productivity breeds low diversity.

Research, Analysis, Primary productivity (Biology), Biodiversity, Evolution (Biology), Evolution, Species diversity, Habitat partitioning (Biology), Habitat partitioning (Ecology)

---

Congress proposes changes in forest diversity mandate

Article Abstract:

The US Congress's move to curtail the authority of the US Forest Service to protect biological diversity on federal lands has drawn stiff opposition from Capitol Hill and environmentalists. The move, if implemented, will affect the powers of the National Forest Management Act (NFMA) to manage fish and wildlife habitats of native and non-native vertebrate species. The NFMA forms the basis for conservational initiatives through out the nation. The Congress's move to weaken the existing regulation is attributed to vagrant policies adopted by the Forest Service in different states.

Laws, regulations and rules, Environmental policy, United States. Congress, Environmental protection, United States. Forest Service

Similar abstracts:

• Abstracts: Biases in diet study methods in the Bonelli's eagle. Diet of the coypu (nutria, Myocastor coypus) in agro-systems of Argentinian Pampas
• Abstracts: Pheromones and regulation of ovulation. The role of allergy in the development of asthma
• Abstracts: Talc-bearing serpentinite and the creeping section of the San Andreas fault. Shades of Titan
• Abstracts: The return of the golden fleece. Fixing a symbiotic circle. Full circle: An Adirondack canoe route traces the return of the wild
• Abstracts: The return of the golden fleece. Successful cultivation of the golden chanterelle

This website is not affiliated with document authors or copyright owners. This page is provided for informational purposes only. Unintentional errors are possible.