Papers by Luis Anibal Solorzano
Forest Science, 2011
Rooting depth affects soil profiles of water uptake and carbon inputs. Here we explore the import... more Rooting depth affects soil profiles of water uptake and carbon inputs. Here we explore the importance of deep roots in a mature tropical forest of eastern Amazonia, where a throughfall exclusion experiment was conducted to test the resilience of the forest to experimentally induced drought. We hypothesized that soil water depletion occurred below the depth previously measured by sensors in 11-m-deep soil pits and that only a small root biomass is necessary to affect water uptake and the isotopic signature of soil CO2. A noninvasive electrical profiling method demonstrated greater depletion of soil water in the 11-18 m depth increment in the exclusion plot compared with the control plot by the end of the 3rd year of the experiment. A fine root biomass of only 0.1 g/cm 3 measured at 3-6 m was sufficient for soil water drawdown and for imparting an isotopic signature of modern soil 14 CO2 in both plots. A soil 13 CO2 profile indicated drought stress in the exclusion plot. Fine root inp...
Land-cover change in eastern Bolivia was documented using Landsat images from five epochs for all... more Land-cover change in eastern Bolivia was documented using Landsat images from five epochs for all landscapes situated below the montane tree line at approximately 3000 m, including humid forest, inundated forest, seasonally dry forest, and cloud forest, as well as scrublands and grasslands. Deforestation in the eastern Bolivia in 2004 covered 45,735 km2, representing ~9% of the original forest cover, with an additional conversion of 9,050 km2 of scrub and savanna habitats representing 17% of total historical land cover change. Annual rates of land cover change increased from 450 km2 yr-1 in the 1960s to ~2,900 km2 yr-1 in the last epoch spanning 2001 to 2004. This study provides Bolivia with a spatially explicit information resource to monitoring future land cover change, prerequisite for proposed mechanisms to compensate countries for reducing carbon emissions as a result of deforestation. It also shows that policies to limit deforestation had no observable impact on reducing defor...
Frontiers in Ecology and the Environment, 2013
E cosystems and biodiversity have long been threatened by natural and anthropogenic stressors (MA... more E cosystems and biodiversity have long been threatened by natural and anthropogenic stressors (MA 2005; Mooney et al. 2009). A stressor is an activity or phenomenon that induces an adverse effect and therefore degrades the condition and viability of a natural system (EPA 2008). The stressors that have most damaged natural systems fall into four general categories: (1) land-use and land-cover change ([LULCC], including habitat fragmentation and degradation, urbanization, and infrastructure development), (2) biological disruptions (introduction of non-native invasive species, diseases, and pests), (3) extractive activities (such as fishing, forestry, and water withdrawals), and (4) pollution (including chemicals, heavy metals, and nutrients). The combined impacts of these stressors are estimated to have altered more than 75% of Earth's ice-free land (Ellis and Ramankutty 2008) and virtually all reaches of the world's oceans (Halpern et al. 2008). Climate change has emerged as a new and increasingly important threat to natural systems (Mooney et al. 2009). Climate change is a stressor in its own right, and it interacts with these other stressors in complex ways. Here we present a conceptual framework of climate interactions with other stressors, survey and categorize current knowledge about the intersection of climate change and these stressors, highlight potential interactions under future climate scenarios, and discuss the implications for developing effective response strategies. n Conceptual framework Climate change affects biodiversity and ecosystems through a variety of pathways; because many ecosystems are already stressed, and because human adaptation and mitigation responses to climate change across sectors can also affect ecosystems, the effects are complex and interacting. The combined effects of climate change and other stressors typically result in increased stress on natural systems, although individual stresses can ameliorate each other. An activity that is a stressor in one system may have a different, neutral, or even positive effect on another system. These interactions can affect the timing, distribution, and severity of the stresses experienced by US CLIMATE-CHANGE IMPACTS
Science, 1993
ried out on the basis of only those species known to reach sizes >5 mm in any linear dimension, 1... more ried out on the basis of only those species known to reach sizes >5 mm in any linear dimension, 12. G. Rosenberg, Am. Malacol. Bull., in press. More than 1000 publications on western Atlantic mollusks were consulted in the compilation of this data base. 13. W. D. Allmon, PalaiosB, 183 (1993). 14. We estimate that the total shelled molluscan fauna of the Pinecrest is about 1050 species. We obtained this number by taking the estimated 801 Pinecrest gastropods and bivalves and adding 20% for species yet to be discovered and 5% for two less diverse classes, the chitons and scaphopods (29). This number is the same as a widely cited estimate for the Pinecrest (9), which listed 300 species, including 170 gastropods, and gave a total of about 1000 species.
Philosophical Transactions of the Royal Society B: Biological Sciences, 2013
A mosaic of protected areas, including indigenous lands, sustainable-use production forests and r... more A mosaic of protected areas, including indigenous lands, sustainable-use production forests and reserves and strictly protected forests is the cornerstone of conservation in the Amazon, with almost 50 per cent of the region now protected. However, recent research indicates that isolation from direct deforestation or degradation may not be sufficient to maintain the ecological integrity of Amazon forests over the next several decades. Large-scale changes in fire and drought regimes occurring as a result of deforestation and greenhouse gas increases may result in forest degradation, regardless of protected status. How severe or widespread these feedbacks will be is uncertain, but the arc of deforestation in south–southeastern Amazonia appears to be particularly vulnerable owing to high current deforestation rates and ecological sensitivity to climate change. Maintaining forest ecosystem integrity may require significant strengthening of forest conservation on private property, which c...
Philosophical Transactions of the Royal Society B: Biological Sciences, 2008
Protected area systems and conservation corridors can help mitigate the impacts of climate change... more Protected area systems and conservation corridors can help mitigate the impacts of climate change on Amazonian biodiversity. We propose conservation design criteria that will help species survivein situor adjust range distributions in response to increased drought. The first priority is to protect the western Amazon, identified as the ‘Core Amazon’, due to stable rainfall regimes and macro-ecological phenomena that have led to the evolution of high levels of biodiversity. Ecotones can buffer the impact from climate change because populations are genetically adapted to climate extremes, particularly seasonality, because high levels of habitat diversity are associated with edaphic variability. Future climatic tension zones should be surveyed for geomorphological features that capture rain or conserve soil moisture to identify potential refugia for humid forest species. Conservation corridors should span environmental gradients to ensure that species can shift range distributions. Ripa...
Global Change Biology, 2004
The spatial distribution of human activities in forest frontier regions is strongly influenced by... more The spatial distribution of human activities in forest frontier regions is strongly influenced by transportation infrastructure. With the planned paving of 6000 km of highway in the Amazon Basin, agricultural frontier expansion will follow, triggering potentially large changes in the location and rate of deforestation. We developed a landcover change simulation model that is responsive to road paving and policy intervention scenarios for the BR-163 highway in central Amazonia. This corridor links the cities of Cuiabá, in central Brazil, and Santarém, on the southern margin of the Amazon River. It connects important soybean production regions and burgeoning population centers in Mato Grosso State with the international port of Santarém, but 1000 km of this road are still not paved. It is within this context that the Brazilian government has prioritized the paving of this road to turn it into a major soybean exportation facility. The model assesses the impacts of this road paving within four scenarios: two population scenarios (high and moderate growth) and two policy intervention scenarios. In the 'business-asusual' policy scenario, the responses of deforestation and land abandonment to road paving are estimated based on historical rates of Amazon regions that had a major road paved. In the 'governance' scenario, several plausible improvements in the enforcement of environmental regulations, support for sustainable land-use systems, and local institutional capacity are invoked to modify the historical rates. Model inputs include data collected during expeditions and through participatory mapping exercises conducted with agents from four major frontier types along the road. The model has two components. A scenario-generating submodel is coupled to a landscape dynamics simulator, 'DINAMICA', which spatially allocates the land-cover transitions using a GIS database. The model was run for 30 years, divided into annual time steps. It predicted more than twice as much deforestation along the corridor in business-as-usual vs. governance scenarios. The model demonstrates how field data gathered along a 1000 km corridor can be used to develop plausible scenarios of future land-cover change trajectories that are relevant to both global change science and the decision-making process of governments and civil society in an important rainforest region.
Ecological Applications, 2004
Forest understory fires are an increasingly important cause of forest impoverishment in Amazonia,... more Forest understory fires are an increasingly important cause of forest impoverishment in Amazonia, but little is known of the landscape characteristics and climatic phenomena that determine their occurrence. We developed empirical functions relating the occurrence of understory forest fires to landscape features near Paragominas, a 35-yr-old ranching and logging center in eastern Amazonia. An historical sequence of maps of forest understory fire was created based on field interviews with local farmers and Landsat TM images. Several landscape features that might explain spatial variation in the occurrence of understory fires were also mapped and co-registered for each of the sample dates, including: forest fragment size and shape, forest impoverishment through logging and understory fire, sources of ignition (settlements and charcoal pits), roads, forest edges, and others. The spatial relationship between forest understory fire and each landscape characteristic was tested by regression analyses. Fire probability models were then developed for various combinations of landscape characteristics. The analyses were conducted separately for years of the El Niñ o Southern Oscillation (ENSO), which are associated with severe drought in eastern Amazonia, and non-ENSO years. Most (91%) of the forest area that burned during the 10-yr sequence caught fire during ENSO years, when severe drought may have increased both forest flammability and the escape of agricultural management fires. Forest understory fires were associated with forest edges, as reported in previous studies from Amazonia. But the strongest predictor of forest fire was the percentage of the forest fragment that had been previously logged or burned. Forest fragment size, distance to charcoal pits, distance to agricultural settlements, proximity to forest edge, and distance to roads were also correlated with forest understory fire. Logistic regression models using information on fragment degradation and distance to ignition sources accurately predicted the location of Ͼ80% of the forest fires observed during the ENSO event of 1997-1998. In this Amazon landscape, forest understory fire is a complex function of several variables that influence both the flammability and ignition exposure of the forest.
AMBIO: A Journal of the Human Environment, 2007
Land-cover change in eastern lowland Bolivia was documented using Landsat images from five epochs... more Land-cover change in eastern lowland Bolivia was documented using Landsat images from five epochs for all landscapes situated below the montane tree line at approximately 3000 m, including humid forest, inundated forest, seasonally dry forest, and cloud forest, as well as scrublands and grasslands. Deforestation in eastern Bolivia in 2004 covered 45 411 km 2 , representing ;9% of the original forest cover, with an additional conversion of 9042 km 2 of scrub and savanna habitats representing 17% of total historical land-cover change. Annual rates of land-cover change increased from ;400 km 2 y À1 in the 1960s to ;2900 km 2 y À1 in the last epoch spanning 2001 to 2004. This study provides Bolivia with a spatially explicit information resource to monitor future land-cover change, a prerequisite for proposed mechanisms to compensate countries for reducing carbon emissions as a result of deforestation. A comparison of the most recent epoch with previous periods shows that policies enacted in the late 1990s to promote forest conservation had no observable impact on reducing deforestation and that deforestation actually increased in some protected areas. The rate of land-cover change continues to increase linearly nationwide, but is growing faster in the Santa Cruz department because of the expansion of mechanized agriculture and cattle farms.
Agriculture, Ecosystems & Environment, 2001
The Intergovernmental Panel on Climate Change (IPCC) has suggested that large-scale use of carbon... more The Intergovernmental Panel on Climate Change (IPCC) has suggested that large-scale use of carbon-neutral or low-carbon biomass-derived energy will be essential in order to limit carbon emissions from the world's energy sector in the future. The IPCC envisions as much as 400 million ha being devoted to biomass energy plantations by 2050. To realize production of biomass energy at such levels-in a manner that would be both biogeophysically sustainable and socially beneficial-will require planning and policy development at sub-national levels, taking into account biogeophysical, social, cultural, economic, institutional, and other factors. This paper presents a method for spatially explicit calculations for estimating potential biomass yields over relatively large geographic regions. The calculations use geo-referenced data inputs that include rainfall, insolation, temperature, soil quality, and soil depth. The methodology is applied to the Northeast region of Brazil, which accounts for 10% of the area of South America. Northeast Brazil is an interesting site for illustrative purposes in part because it is biologically, geologically, and socioeconomically diverse and in part because the main electric utility serving the region is exploring the development of biomass-based electricity generation to meet future increases in electricity demand. Results from a spatially explicit, biogeophysical model like that presented here could be combined with other spatially explicit information such as road layouts, existing land uses, population densities and growth rates, distributions of endangered species, archeologically significant areas, etc. to inform planning and policy development related to biomass energy at a regional or national level. One illustration of such an analysis is included here. For on-the-ground implementation of biomass production systems, finer-resolution analysis and intimate local participation is essential.
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Papers by Luis Anibal Solorzano