Models predict that food-web structure is regulated by both consumers and resources, and the strength of this control is dependent on trophic position and food-web length. To test these hypotheses, a meta-analysis was conducted of 11 fish (consumer)-by-nutrient (resource) factorial plankton community experiments. As predicted, zooplankton biomass was under strong consumer control but was weakly...

1. General hypotheses have related nutrient stoichiometry to physiology and structure for tracheophytes across global resource gradients. These hypotheses have not been tested on bryophytes despite their importance in numerous ecosystem processes. 2. Twelve bryophyte species were sampled across an elevation · soil age matrix representing a dramatic range of climates onMauna Loa, Hawaii. 3. We t...

A recent theory of the vertical distribution of phytoplankton considers how interacting niche construction processes such as resource depletion, behavior, and population dynamics contribute to spatial heterogeneity in the aquatic environment. In poorly mixed water columns with opposing resource gradients of nutrients and light, theory predicts that a species should aggregate at a single depth. ...

Ecologists have long been interested in understanding the strengths of consumer and resource limitation in influencing communities. Here we ask three questions concerning the relative importance of nutrients and grazing fishes to primary producers of a tropical Andean stream: (1) Are stream algae nutrient limited? (2) Are top-down and bottom-up forces of dual importance in limiting primary prod...

Organic resources play a critical role in both short-term nutrient availability and longer-term maintenance of soil organic matter in most smaller holder farming systems in the tropics. Despite this importance, there is little predictive understanding for the management of organic inputs in tropical agroecosystems. In this paper, an organic resource database (ORD) is introduced that contains in...

1 Variation in resource requirements among plant species may cause changes in community composition when resource supply rates vary. Because exotic plants may differ in their requirements compared with native plants, changes in resource levels or ratios may change their invasive potential. The concentration hypothesis, nutrient balance hypothesis and resource ratio hypothesis make different pre...

IMPORTANCE Physicians must participate in end-of-life discussions, but they understand poorly their patients' end-of-life values and preferences. A better understanding of these preferences and the effect of baseline attitudes will improve end-of-life discussions. OBJECTIVE To determine how baseline attitudes toward quality vs quantity of life affect end-of-life resource allocation. DESIGN,...

In competition-dominated communities, traits promoting resource conservation and competitive ability are expected to have an important influence on species relative abundance (SRA). Yet, few studies have tested the trait-abundance relations in the line of species trade-off in resource conservation versus acquisition, indicating by multiple traits coordination. We measured SRA and key functional...

There is currently much debate about sources of pollution, particularly nutrient pollution of surface and groundwaters. It frequently appears that everyone is quite confident everyone else is contributing far more than they are. The reality, particularly for nutrient pollution, is that we all are part of the problem and must be part of the solution. This paper offers a science-based perspective...