Life-history theory predicts that populations experiencing different levels of extrinsic mortality will evolve divergent reproductive strategies. Previous work in the live-bearing fish Brachyrhaphis rhabdophora shows that individuals from populations that occur with piscivorous fish mature earlier and at smaller sizes and have more and smaller offspring than fish from populations without predat...

Since the response to differences in resource availability is most pronounced in smaller individuals of vascular epiphytes such as Werauhia sanguinolenta Cogn. et Marchal (Bromeliaceae), I expected variation in growth and survival of small individuals to play an important role in the dynamics of entire populations. Four annual censuses (2002–2005) of three study populations, which were located ...

Environmental factors influence the dynamics and regulation of biological populations through their influences on demographic variables, but demographic mechanisms of population regulation have received little attention. We investigated the demographic basis of regulation of Columbian ground squirrel (Spermophilus columbianus) populations under natural and experimentally food-supplemented condi...

a trend of significant increase in municipal solid waste generation has been recorded worldwide. this has been found due to over population growth rate, industrialization, urbanization and economic growth. consumerism speed has been found very high covering around more then 50% of total population since last decade due to higher economic growth, which has ultimately resulted in increased solid ...

The world is in the midst of an unprecedented demographic transition. In developed and developing countries alike, populations are ageing as fertility rates decline and longevity increases. Together, these forces imply slower population growth and an increasing share of the elderly in the population, although the extent and speed of these changes will differ signifi cantly across countries. Dem...

Explaining variation in population growth rates is fundamental to predicting population dynamics and population responses to environmental change. In this study, we used matrix population models, which link birth, growth and survival to population growth rate, to examine how and why population growth rates vary within and among 50 terrestrial plant species. Population growth rates were more sim...

BACKGROUND The trade in manta ray gill plates has considerably increased over the last two decades. The resulting increases in ray mortality, in addition to mortality caused by by-catch, has caused many ray populations to decrease in size. The aim of this study was to ascertain how yearling and juvenile growth and survival, and adult survival and reproduction affect reef manta ray (Manta alfred...

When vital rates depend on population structure (e.g., relative frequencies of males or females), an important question is how the long-term population growth rate λ responds to changes in rates. For instance, availability of mates may depend on the sex ratio of the population and hence reproductive rates could be frequency-dependent. In such cases change in any vital rate alters the structure,...

We begin by noting how India is highly overpopulated and that this creates negative externalities for world environment. Next, we note that females in child-bearing ages alone determine the birth rate, compounding the population growth anywhere. Third, forcing families to have unwanted daughters can increase discrimination against women. Fourth, most countries impose no restrictions on women ch...