We examined the effects of an amended mixture of three pesticides, atrazine (72.7 g), S-metolachlor (54.5 g), and permethrin (both cis and trans isomers; 11.4 g), on 10-day sediment toxicity to Hyalella azteca in a managed natural backwater wetland after a simulated agricultural runoff event. Sediment samples were collected at 10, 40, 100, 300, and 500 m from inflow 13 days prior to amendment and 1, 5, 12, 22, and 36 days post-amendment. Background pesticide concentrations ranged from

Across much of the globe, fire is a major disturbance agent of forest and grassland communities. The removal of fire from previously fire-maintained ecosystems, which has occurred in many areas, changes species composition, favoring later less fire tolerant species over fire-adapted ones. A recent measured increase in the rate of hybridization between the fire-adapted shortleaf pine (Pinus echinata) and less fire-adapted loblolly pine (P. taeda) suggests that introgression may be an emerging threat to shortleaf pine as a genetically distinct species.

Humans have been changing the natural fire regimes in most Brazilian vegetation types for over 4000 years. Natural lightning fires can easily happen in savannas and grasslands, but they are rare in the moist rainforests. Today, anthropogenic fires are frequent in both the fire-adapted cerrado (Brazilian savanna) and the fire-sensitive rainforest. In this paper, I compare two very different biomes concerning their susceptibilities and responses to fire: the Amazon rainforest and the cerrado.

Connectivity is a key concern in natural resource planning. Many studies have focused on the development of methods, tools and indices for the assessment of both components of connectivity: structural and functional. In particular, approaches based on graph theory principles have been recently proposed and are being increasingly applied to guide landscape connectivity conservation. However, forest planners and managers still need effective and operational methodologies to detect those landscapes where connectivity should be treated as a particularly critical conservation concern.

Question: Does flooding of rice fields after cultivation contribute to wetland plant conservation in southern Brazil? Location: Rice fields in the coastal plain of southern Brazil. Methods: Six rice fields with different management practices were randomly selected (three dry rice fields and three flooded rice fields). Six collections were carried out over the rice cultivation cycle. Richness and biomass were measured using the quadrat method. Results: A total of 88 macrophyte species was recorded.

The Adja plateau (Benin) is densely populated by tenant and landowner farmers engaged in oil palm based cropping. Landowners use oil palm sap for the production of sodabi (a local spirit), and an oil palm fallow (if no crops are grown beneath the palms) to restore soil fertility. In this area, growing oil palm for its oil is uncommon. Tenants access the land under specific contracts but are not allowed to plant oil palm.

The concept of critical nutrient amounts (CNA) for a watershed was developed to address eutrophication in surface waters from diffuse (non-point) source pollution. CNA is defined as the maximum allowable applied or generated amount (AGA) of a nutrient from natural and human sources that can be emitted and still allow compliance with water quality standards.

"The 75 year legacy database including discharge, sediment loss, land management, and mete- orological data for the USDA-ARS Riesel Watersheds, Riesel, TX, USA has been available on the web for more than a decade (www.ars.usda.gov/spa/hydro-data) and used in numerous studies and publications; however, only recently have these data been added to the Sustaining the Earth’s Watersheds, Agricultural Research Data System (STEWARDS) database (www.nrrig.mwa.ars.usda.gov/stewards/

Agricultural land use and sugarcane residue management effects on soil bacterial communities at two long-term sites in KwaZulu/Natal, South Africa, were investigated by PCR-DGGE. Land uses at site 1 were maize [M]; pre-harvest burnt sugarcane [SC]; permanent kikuyu pasture [KIK]; pine forest [PF]; wattle forest [W] and undisturbed native grassland [NAT], whereas land managements at site 2 were pre-harvest burning of sugarcane [Bto] or green cane harvesting with retention of a trash mulch [T] (with [F] or without [Fo] fertilizer additions).