Carbon neutral expansion of oil palm plantations in the Neotropics

Alternatives to ecologically devastating deforestation land use change trajectories are needed to reduce the carbon footprint of oil palm (OP) plantations in the tropics. Although various land use change options have been proposed, so far, there are no empirical data on their long-term ecosystem carbon pools effects. Our results demonstrate that pasture-to-OP conversion in savanna regions does not change ecosystemcarbon storage, after 56 years in Colombia. Compared to rainforest conversion, this alternative land use change reduces net ecosystem carbon losses by 99.7 +/- 9.6%. Soil organic carbon (SOC) decreased until 36 years after conversion, due to a fast decomposition of pasture-derived carbon, counterbalancing the carbon gains in OP biomass. The recovery of topsoil carbon content, suggests that SOCstocks might partly recover during a third plantation cycle. Hence, greater OP sustainability can be achieved if its expansion is oriented toward pasture land

Herbert Hoover Elementary / Charleston Complete Corridor Plan

Completed as a part of CRP 425 bicycle and pedestrian planning, led by Dr. William Riggs, this planning project assessed the Herbert Hoover Elementary site and Charleston corridor in the City of Palo Alto with an aim to bring a complete streets strategy to the area. The plans recommend improved accessibility for bicycles and pedestrians along Charleston Road including modal separation between bicyclists and pedestians, improved vehicular flows to mitigate vehicular traffic congestion during peak hours and increased innovation in safety features to prevent pedestrian-vehicle conflicts

Impacts of the IUCN Red List of Ecosystems on conservation policy and practice

In 2014, the International Union for Conservation of Nature adopted the Red List of Ecosystems (RLE) criteria as the global standard for assessing risks to terrestrial, marine, and freshwater ecosystems. Five years on, it is timely to ask what impact this new initiative has had on ecosystem management and conservation. In this policy perspective, we use an impact evaluation framework to distinguish the outputs, outcomes, and impacts of the RLE since its inception. To date, 2,821 ecosystems in 100 countries have been assessed following the RLE protocol. Systematic assessments are complete or underway in 21 countries and two continental regions (the Americas and Europe). Countries with established ecosystem policy infrastructure have already used the RLE to inform legislation, land-use planning, protected area management, monitoring and reporting, and ecosystem management. Impacts are still emerging due to varying pace and commitment to implementation across different countries. In the future, RLE indices based on systematic assessments have high potential to inform global biodiversity reporting. Expanding the coverage of RLE assessments, building capacity and political will to undertake them, and establishing stronger policy instruments to manage red-listed ecosystems will be key to maximizing conservation impacts over the coming decades

Richness, diversity, and factors influencing occupancy of mammal communities across human-modified landscapes in Colombia

As human-modified landscapes are increasing in the tropics, it becomes critical to understand how they affect mammal communities to reconcile conservation and development. We combined land cover information and camera-trapping data to explore the effects of agricultural expansion on mammals in the Magdalena river valley of Colombia. We estimated species diversity, evenness, and dominance across two agricultural landscapes, modified by cattle ranching and oil palm cultivation. We further assessed which variables influence species- and community-level occupancy using multi-species occupancy models. Results highlight that modified landscapes display lower species richness, diversity and evenness, and higher dominance than more pristine sites. Residual forest cover and distance to water had significant effect on community occupancy (positive and negative respectively). Forests were particularly important for pumas, ocelots, lowland pacas, Central American agoutis, and crab-eating raccoons while wetlands had a positive effect on jaguars, the apex predator in the region. The influence of anthropogenic pressure was not clearly evident, though pastures were not valuable habitats for any mammal species, as they had a negative, yet not significant, effect on species and community occupancy. In light of rapidly expanding agriculture across the tropics, our findings highlight species-specific responses to disturbance that can inform land use planning and conservation policies. We stress the conservation value of forest and wetland habitat to mammal occupancy in heterogeneous ecosystems. Moreover, our results demonstrate that oil palm and crop expansion should target existing pastures, which displayed limited conservation value for Neotropical mammals but occupy vast swathes of land across Latin America

Avoiding Costly Conservation Mistakes: The Importance of Defining Actions and Costs in Spatial Priority Setting

Background: The typical mandate in conservation planning is to identify areas that represent biodiversity targets within the smallest possible area of land or sea, despite the fact that area may be a poor surrogate for the cost of many conservation actions. It is also common for priorities for conservation investment to be identified without regard to the particular conservation action that will be implemented. This demonstrates inadequate problem specification and may lead to inefficiency: the cost of alternative conservation actions can differ throughout a landscape, and may result in dissimilar conservation priorities

Population Genomics of Parallel Adaptation in Threespine Stickleback using Sequenced RAD Tags

Next-generation sequencing technology provides novel opportunities for gathering genome-scale sequence data in natural populations, laying the empirical foundation for the evolving field of population genomics. Here we conducted a genome scan of nucleotide diversity and differentiation in natural populations of threespine stickleback (Gasterosteus aculeatus). We used Illumina-sequenced RAD tags to identify and type over 45,000 single nucleotide polymorphisms (SNPs) in each of 100 individuals from two oceanic and three freshwater populations. Overall estimates of genetic diversity and differentiation among populations confirm the biogeographic hypothesis that large panmictic oceanic populations have repeatedly given rise to phenotypically divergent freshwater populations. Genomic regions exhibiting signatures of both balancing and divergent selection were remarkably consistent across multiple, independently derived populations, indicating that replicate parallel phenotypic evolution in stickleback may be occurring through extensive, parallel genetic evolution at a genome-wide scale. Some of these genomic regions co-localize with previously identified QTL for stickleback phenotypic variation identified using laboratory mapping crosses. In addition, we have identified several novel regions showing parallel differentiation across independent populations. Annotation of these regions revealed numerous genes that are candidates for stickleback phenotypic evolution and will form the basis of future genetic analyses in this and other organisms. This study represents the first high-density SNP–based genome scan of genetic diversity and differentiation for populations of threespine stickleback in the wild. These data illustrate the complementary nature of laboratory crosses and population genomic scans by confirming the adaptive significance of previously identified genomic regions, elucidating the particular evolutionary and demographic history of such regions in natural populations, and identifying new genomic regions and candidate genes of evolutionary significance

El Guaviare: Efectos de la colonización ganadera en un área de bosque tropical amazónico

La productividad de las explotaciones pecuarias bajo las condiciones amazónicas no logra un nivel sostenido y decrece con el paso del tiempo, volviéndose marginal al cabo de diez años o más, de manera que solamente explotaciones muy grandes y de tipo extensivo logran mantener alguna rentabilidad

Modeling unplanned landscape change: A Colombian case study

The broad aim of this study is, to contribute to a broader and more comprehensive understanding of the patterns, processes and drivers of unplanned land cover change in the tropics, using Colombia as a study case. Land cover change is an important global issue because of the expanding ecological footprint of a rapidly increasing human population and per capita level of resource consumption. This has a major impact on natural ecosystems and their function at the local (hundreds of square kilometers) and global scales. The understanding of extent and rate of land cover change is an important issue confronting biodiversity conservation, land use planning, protected area management, and global climate change analysis. Tropical deforestation is the major source of global land cover change, with the highest absolute rates occurring in South America, especially in the Brazilian Amazon, where government planning is an important driver of deforestation. However, unplanned deforestation for cropping and ranching is also occurring in Colombia. This is of international concern because Colombias diverse ecosystems support high levels of species richness and endemism. Improving the understanding of the spatial and temporal patterns and drivers ofland cover change (both deforestation and regeneration) is an important step in developing planning and conservation strategies to address this problem. I applied a spatial and temporal statistical modelling approach to predict changes in land cover in Colombia at the local (100 km2), regional (104 km2) and national (106 km2) levels, with a timeframe spanning from decades to centuries. As dependant variable data, binary forest/non-forest data are used. Explanatory variables comprise biophysical and socioeconomic data sourced from a broad range of information sources, including remotely sensed data from aerial photographs and satellite images, secondary sources of biophysical and socioeconomic data, and historical data. At the local-level, I addressed the deforestation process over the last 60 years using six case studies of 100 km2 of humid lowland forests, by applying logistic regression and spatial analysis. At the regional-level, I studied the deforestation in the Caquetá colonization front of the Colombian Amazon region from 1988-2004 by applying a forest-cover zoning method and logistic regression models to predict deforestation and forest regeneration from biophysical and socio-economic explanatory variables. At the national level, I quantified and analysed patterns and drivers of land cover change over the past 500 years for key periods of Colombian history, and identified the extent and duration of impacts on broad ecosystem types. At the national and regional-levels, I also modelled current landscape transformation patterns and predicted areas at a high risk of future deforestation using a joint logistic regression and regression tree approach. I discovered that the rate of deforestation across several lowland regions of Colombia follows a simple sigmoid pattern composed of four phases of transformation: an initial phase of gradual forest loss; an intermediate phase of rapid loss; a second intermediate phase where the rate of decline slows; and a final phase where the forest loss stabilises and is balanced by forest regeneration creating a dynamic equilibrium. At the end of this final phase, the landscape is in a highly transformed state with forest cover stabilizing at 2 to 10% of the original extent and an average forest patch size of 15.4 (± 9.2) ha. As a general rule, the transformed landscape will have two forest components: a stable component of remnant mature tropical forests, and a dynamic component of secondary forests of different ages that is repeatedly cleared. A second important discovery was that unplanned deforestation in the Colombian Amazon moves as a colonisation wave, extending from population centres. The rate of movement was 0.84 km.yr-1 between 1989 and 2002. The regional average annual deforestation rate was 2.6%, but varied locally between 1.8% (regeneration) and 5.3%. The parallel deforestation and regeneration processes operating within the colonization front showed consistent patterns and rates directly related to the proportion of forest in the neighbourhood, with the highest rates of deforestation occurring in the areas with intermediate (40-60%) forest cover, following an overall quadratic function, and therefore confirming the sigmoid pattern across an entire colonization front. Landscapes with intermediate forest cover also have the highest density of edge habitat, with the deforestation process mimicking the spread of disease. At the national-level, the study reveals two important outcomes. First, there are significant regional differences in the spatial and temporal patterns and drivers of land cover change. The importance of such regional differences in factors explainingland cover change is highlighted by the greatest discrimination ability shown by a regional-level classification tree model. The coefficients and significance of variables in a regional logistic regression model confirmed these differences. Overall, factors related to accessibility (distance to roads and towns) had the strongest influence on the probability of deforestation. The second national-level outcome highlights the need for a longer-term historical perspective spanning centuries to understand present-day landscapes and their level of human impact. The historical analysis reveals that the main drivers of landscape change varied in the early colonial period, with cattle grazing becoming increasingly important, and finally the high impact of economic globalization in the 1990s. The historic land cover maps show the transformed areas increasing from approximately 15 million ha in 1500 to 42 million ha in 2000. Also, during this period, the transformed areas changed from predominantly cropping land uses in 1500 to predominantly (< 75%) grazing in 2000. The research outcomes collectively provide an understanding of the spatial dynamics of unplannedland cover change in tropical forest landscapes, by showing how deforestation and regeneration processes vary along a transformation gradient, and linking the amount of remnant forests is related to the rate of change. The work has implications for policy and management. For example, the method of calculating the movement speed of a colonization front provides a spatially explicit prediction of threat that can be used in conservation planning. The improved understanding of the deforestation and regeneration dynamics over an entire colonization fronts permits more accurate calculation of carbon budgeting for climate change applications. I recommend that future work test of the generalities presented here in both, countries with unplanned deforestation and countries with planned land clearing, to evaluate the effects government controlled planning has on the end result of human transformed landscapes in tropical and subtropical forest regions

Modeling the age of tropical moist forest fragments in heavily-cleared lowland landscapes of Colombia

Increasingly, large areas of native tropical forests are being transformed into a mosaic of human dominated land uses with scattered mature remnants and secondary forests. In general, at the end of the land clearing process, the landscape will have two forest components: a stable component of surviving mature forests, and a dynamic component of secondary forests of different ages. As the proportion of mature forests continues to decline, secondary forests play an increasing role in the conservation and restoration of biodiversity. This paper aims to predict and explain spatial and temporal patterns in the age of remnant mature and secondary forests in lowland Colombian landscapes. We analyse the age distributions of forest fragments, using detailed temporal land cover data derived from aerial photographs. Ordinal logistic regression analysis was applied to model the spatial dynamics of mature and secondary forest patches. In particular, the effect of soil fertility, accessibility and auto-correlated neighbourhood terms on forest age and time of isolation of remnant patches was assessed. In heavily transformed landscapes, forests account for approximately 8% of the total landscape area, of which three quarters are comprised of secondary forests. Secondary forest growth adjacent to mature forest patches increases mean patch size and core area, and therefore plays an important ecological role in maintaining landscape structure. The regression models show that forest age is positively associated with the amount of neighbouring forest, and negatively associated with the amount of neighbouring secondary vegetation, so the older the forest is the less secondary vegetation there is adjacent to it. Accessibility and soil fertility also have a negative but variable influence on the age of forest remnants. The probability of future clearing if current conditions hold is higher for regenerated than mature forests. The challenge of biodiversity conservation and restoration in dynamic and spatially heterogeneous landscape mosaics composed of mature and secondary forests is discussed. (c) 2004 Elsevier B.V. All rights reserved