SciTalk

Brosse, S., G. Grenouillet, et al. (2011). “Small-scale gold mining erodes fish assemblage structure in small neotropical streams.” Biodiversity and Conservation: 1013-1026.
The current gold rush experienced by the Guiana shield is profoundly disturbing freshwater ecosystems. Indeed, streams act as receptors for the water that drains gold mining sites and that contain a high load of sediment and toxicants. We here investigated how gold mining activities affect the structure of fish assemblages in small forest streams in French Guiana. We selected six streams subjected to different types of gold mining impact (reference, former gold mining and currently exploited sites) to measure the impact of gold mining on downstream fish assemblages, but also to determine the resilience of fish assemblages after stopping mining activities. Although overall descriptors of the assemblage such as species richness and fish biomass were not sensitive to gold mining, the fish taxonomic composition was strongly influenced. Furthermore, we showed that the functional structure of fish assemblages was significantly affected by the mining activities favouring smaller and ubiquitous fish at the expense of bigger and habitat specialist species. Even in areas where mining activities had stopped for some time, site resilience was incomplete. http://dl.dropbox.com/u/606110/Brosse%20et%20al.%20-%202011.pdf

Loarie, S. R., D. B. Lobell, et al. (2011). “Direct impacts on local climate of sugar-cane expansion in Brazil.” Nature Climate Change 1: 1-5.
The increasing global demand for biofuels will require conversion of conventional agricultural or natural ecosystems. Expanding biofuel production into areas now used for agriculture reduces the need to clear natural ecosystems, leading to indirect climate benefits through reduced greenhouse-gas emissions and faster payback of carbon debts1. Biofuel expansion may also cause direct, local climate changes by altering surface albedo and evapotranspiration2, but these effects have been poorly documented. Here we quantify the direct climate effects of sugar-cane expansion in the Brazilian Cerrado, on the basis of maps of recent sugar-cane expansion and natural-vegetation clearance combined with remotely sensed temperature, albedo and evapotranspiration over a 1.9 million km2 area. On a regional basis for clear-sky daytime conditions, conversion of natural vegetation to a crop/pasture mosaic warms the cerrado by an average of 1.55 (1.45–1.65) °C, but subsequent conversion of that mosaic to sugar cane cools the region by an average of 0.93 (0.78–1.07) °C, resulting in a mean net increase of 0.6    . Our results indicate that expanding sugar caneinto existing crop and pasture land has a direct local cooling effect that reinforces the indirect climate benefits of this land-use option. http://dl.dropbox.com/u/606110/Loarie%20et%20al.%20-%202011.pdf

Nogueira, S. S. C. and S. L. G. Nogueira-Filho (2011). “Wildlife farming: an alternative to unsustainable hunting and deforestation in Neotropical forests?” Biodiversity and Conservation.
Wild animals have been a source of food and income through subsistence hunting by forest-dwelling people in Neotropical countries in spite of the fact that hunting appears to be unsustainable as it leads to the depletion of wild fauna. Laws in Brazil and other Latin American countries forbid hunting but allow the commercial use of captive-bred animals. Notwithstanding the fact that this is a controversial topic among conservationists, in this paper we propose that wildlife farming in the Neotropics can be an alternative to the over-hunting and deforestation that are carried out for the production of traditional food and pastures for livestock. This review sets out this proposal, and discusses the implications for tropical forest integrity and rural population dependency on forest resources. We discuss the ecological and economical advantages of wildlife farming and its constraints as a conservation tool, using collared peccary (Pecari tajacu) farming in the Amazon region as a model. Productivity levels may reach 19,000 times higher than those obtained from the management of peccaries from forests in the Amazon region. This can be achieved with an easily obtainable diet composed of forest fruits and locally available agricultural by-products. Therefore, establishing captive management programs for peccaries is an effective way of avoiding wild stock depletion, deforestation, and guaranteeing the livelihood of forest dwellers in the Neotropics. However, it is essential that governmental and/or non-governmental agencies be involved in providing subsides to establish peccary farms, provide technical assistance, and introducing peccary captive breeding centers to supply founder stock. http://dl.dropbox.com/u/606110/Nogueira%2C%20Nogueira-Filho%20-%202011.pdf

Pitman, N. C. a., D. Norris, et al. (2011). “Four years of vertebrate monitoring on an upper Amazonian river.” Biodiversity and Conservation: 827-849.
Long-term monitoring of tropical forest animals lags far behind long-term monitoring of tropical forest plants, compromising ecologists’ ability to identify parallel trends. On 257 occasions over 4 years, park guards in a newly protected lowland Amazonian forest in southeastern Peru tallied individuals of 31 reptile, bird, and mammal species sighted along a 47-km stretch of river. Each survey entailed ~3 h of observation from a motorized boat; total survey effort was 892 h and ~12,048 km. Our primary goals were descriptive: to establish baseline sighting rates for these species and to document trends over time and the influence of environmental and sampling factors on sightings. Our secondary goals were to identify the advantages and disadvantages of river-based monitoring and to assess how useful these data are for ecologists and protected areas managers. Over the 4 years of monitoring we observed 1.8 animals/km. More than 90% of recorded individuals belonged to seven common taxa: two reptiles, four birds, and one mammal. Season was the most frequent correlate of sighting frequency; sightings increased in dry season. For the majority of taxa common enough to analyze, sightings increased over the 4 years of monitoring; this is possibly a result of reduced hunting since the establishment of the protected area. Compared to forest-based surveys, river-based surveys were inefficient at recording most mammals. Results to date suggest that river-based surveys can be a valuable, inexpensive tool for monitoring some ecologically important Amazonian animals, and especially those in protected areas. http://dl.dropbox.com/u/606110/Pitman%20et%20al.%20-%202011.pdf

Pitman, N. C. A., G. Stocks, et al. (2011). “Volume and Geographical Distribution of Ecological Research in the Andes and the Amazon , 1995-2008.” Tropical Conservation Science 4(1): 64-81.
The Andes range and the Amazon basin represent the most diverse biological community on earth and the largest  tropical  forest  on earth,  respectively,  but  they  are  historically  understudied  by  biologists.    In this paper we provide the first quantitative description of the volume and geographical distribution of ecological research in these regions.  We compiled a dataset of all articles based on the Andes and Amazon regions published  in  two  prominent  international  tropical  ecology  journals  between  1995  and  2008.    During this period, the number of scientific articles based on research in the Amazon was half that based on research in Central  America, while  the Andes  scored  among  the  least-studied  of  all  tropical  regions.    Brazil  was  the leading base for Amazonian studies and Ecuador the primary location for Andean studies, but Ecuador led both  categories  and  Brazil  came  last  when  research  effort  was standardized  by  area.   Most Amazonian research took place in three regions—Manaus, southeastern Peru, and eastern Ecuador—with ~31 percent of all papers coming from four field stations in those regions.  Andean research focused overwhelmingly on the northern Andes.  Research in the Andes range and the Amazon basin remains scattered, patchy, and far below  its  potential.  We  propose steps  that  funding  agencies  can  take  to  increase  research  output  and reduce geographical bias in the study of South America’s richest ecosystems. http://dl.dropbox.com/u/606110/Pitman%20et%20al.%20-%202011%20copy.pdf

Swenson, J. J., C. E. Carter, et al. (2011). “Gold Mining in the Peruvian Amazon: Global Prices, Deforestation, and Mercury Imports.” PLoS ONE 6: e18875.
Many factors such as poverty, ineffective institutions and environmental regulations may prevent developing countries from managing how natural resources are extracted to meet a strong market demand. Extraction for some resources has reached such proportions that evidence is measurable from space. We present recent evidence of the global demand for a single commodity and the ecosystem destruction resulting from commodity extraction, recorded by satellites for one of the most biodiverse areas of the world. We find that since 2003, recent mining deforestation in Madre de Dios, Peru is increasing nonlinearly alongside a constant annual rate of increase in international gold price (~18%/yr). We detect that the new pattern of mining deforestation (1915 ha/year, 2006–2009) is outpacing that of nearby settlement deforestation. We show that gold price is linked with exponential increases in Peruvian national mercury imports over time (R2 = 0.93, p = 0.04, 2003–2009). Given the past rates of increase we predict that mercury imports may more than double for 2011 (~500 t/year). Virtually all of Peru’s mercury imports are used in artisanal gold mining. Much of the mining increase is unregulated/artisanal in nature, lacking environmental impact analysis or miner education. As a result, large quantities of mercury are being released into the atmosphere, sediments and waterways. Other developing countries endowed with gold deposits are likely experiencing similar environmental destruction in response to recent record high gold prices. The increasing availability of satellite imagery ought to evoke further studies linking economic variables with land use and cover changes on the ground. http://dl.dropbox.com/u/606110/Swenson%20et%20al.%20-%202011.pdf

Xu, L., A. Samanta, et al. (2011). “Widespread decline in greenness of Amazonian vegetation due to the 2010 drought.” Geophysical Research Letters 38: 2-5.
During this decade, the Amazon region has suffered two severe droughts in the short span of five years – 2005 and 2010. Studies on the 2005 drought present a complex, and sometimes contradictory, picture of how these forests have responded to the drought. Now, on the heels of the 2005 drought, comes an even stronger drought in 2010, as indicated by record low river levels in the 109 years of bookkeeping. How has the vegetation in this region responded to this record-breaking drought? Here we report widespread, severe and persistent declines in vegetation greenness, a proxy for photosynthetic carbon fixation, in the Amazon region during the 2010 drought based on analysis of satellite measurements. The 2010 drought, as measured by rainfall deficit, affected an area 1.65 times larger than the 2005 drought – nearly 5 million km2 of vegetated area in Amazonia. The decline in greenness during the 2010 drought spanned an area that was four times greater (2.4 million km2) and more severe than in 2005. Notably, 51% of all drought-stricken forests showed greenness declines in 2010 (1.68 million km2) compared to only 14% in 2005 (0.32 million km2). These declines in 2010 persisted following the end of the dry season drought and return of rainfall to normal levels, unlike in 2005. Overall, the widespread loss of photosynthetic capacity of Amazonian vegetation due to the 2010 drought may represent a significant perturbation to the global carbon cycle. http://dl.dropbox.com/u/606110/Xu%20et%20al.%20-%202011.pdf