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Legal frameworks could play a key role in enabling countries to meet their ambitious forest landscape restoration (FLR) targets. In this paper, we examine the perceptions of different types of stakeholders from 17 Latin American countries on aspects of forestry and environmental legal frameworks that enable or hamper FLR interventions at the national level. We first reviewed general, environmental, social and financial aspects of existing legal frameworks in order to provide the basis for a mixed qualitative - quantitative analysis of perceptions. The analysis combines information from semi-structured interviews and a Likert-scale questionnaire given to relevant stakeholders involved in implementing FLR interventions in the countries assessed. We interviewed stakeholders from government, academia, national non-governmental organizations (NGOs) and local private and non-governmental organizations. We found that most legal frameworks are in the jurisdiction of either the agriculture or the environmental sectors. As a whole, we did not find evidence of the kind of legal frameworks articulation needed to enable the coordinated deployment of various forest FLR interventions across landscapes. We found efforts in Brazil, Colombia, Guatemala, Costa Rica, Ecuador and Mexico to improve cross-sectorial communication and legislation, and to develop innovative financial mechanisms to support FLR interventions. In general, interviewees had a positive perception of the content of legal frameworks in their countries; however, they highlighted weak implementation capacities, insufficient funding, sectorial and social conflicts, and lack of transparency as key impediments for policy implementation. Academic and NGO stakeholders perceived the content of the legal frameworks more negatively, whereas government officials were more positive. Different perceptions and the prevalence of cross-sectorial conflicts highlight the importance of efforts aimed at improving governance mechanisms and policy integration in the region. In addition, a targeted effort is needed to develop long-term, funding options that are public, private or mixed, and to disseminate information on the importance of FLR interventions for national economies and human well-being. We consider our results as a preliminary overview of the legal environment for FLR implementation in Latin America.

There is strong upswing in conservation and restoration efforts in Latin America (LA), particularly in the recent decades after several countries have committed to international agreements such as the Aichi targets of the Convention on Biological Diversity, Initiative 20×20, and the Bonn Challenge. To fulfill these agreements, the practice of ecological restoration has to be defined based on ecological knowledge, but also on the specific social, economic, and legal aspects of each country in the region. Here, we give some examples about the national understanding of ecological restoration in 10 countries of LA. We identify difficulties and opportunities to define restoration priorities and needs, and discuss some approaches to cope with economic constraints and agreements, including the potential role of restoration networks in this process. On the basis of the socioecological complexity of these countries and the expectations they have in relation to restoration, we proposed four approaches to guide restoration practice and policy in the region: (1) including biodiversity and ecosystem services approach into ecosystem restoration initiatives; (2) promoting restoration in their frequently human-modified landscapes; (3) accounting for cost–benefit trade-offs; and (4) assembling “horizontal” communication frameworks. These approaches should be based at national levels, but adapted to local-regional levels, in a bottom-up perspective. We consider that national and international restoration networks in the region can help to overcome difficulties, fostering a solid scientific community, helping to develop national approaches that better match the specific conditions of each country and enhancing communication among different groups of stakeholders.

Enzyme activities (EAs) respond to contamination in several ways depending on the chemical form and content of heavy metals and metalloids (HMs) and their interactions with various soil properties. A systematic and mechanistic understanding of EA responses to HM contamination in soil is necessary for predicting the consequences for nutrient availability and the cycling of carbon (C), nitrogen (N), phosphorus (P) and sulphur (S). In this study, a meta-analysis based on 671 observations found the activities of seven enzymes to decrease in response to soil contamination with Pb, Zn, Cd, Cu and As. HM contamination linearly reduced the activities of all enzymes in the following order: arylsulfatase > dehydrogenase > β-glucosidase > urease > acid phosphatase > alkaline phosphatase > catalase. The activities of two endoenzymes: arylsulfatase (partly as exoenzyme) and dehydrogenase were reduced by 72% and 64%, respectively. These reductions were two times greater than of exoenzymes: β-glucosidase, urease, acid phosphatase, alkaline phosphatase and catalase (partly endoenzyme). This reflects the much stronger impact of HMs on living microorganisms and their endoenzymes than on extracellular enzymes stabilized on clay minerals and organic matter. Increasing clay content weakened the negative effects of HM contamination on EAs. All negative effects of HMs on EAs decreased with soil depth because HMs remain mainly in the topsoil. EAs involved in the cycling of C and S were more affected by HMs than the enzymes associated with the cycling of N and P. Consequently, HM contamination may alter the stoichiometry of C, N, P and S released by enzymatic decomposition of organic compounds that consequently affect microbial community structure and activity.

Author(s): Brancalion, Pedro HS; Meli, Paula; Tymus, Julio RC; Lenti, Felipe EB; Benini, Rubens M; Silva, Ana Paula M; Isernhagen, Ingo; Holl, Karen D

Los recientes compromisos internacionales adquiridos en el contexto de la restauracion de areas degradadas y deforestadas han catalizado un movimiento de proporciones globales. En particular, los paises de America Latina se han comprometido a restaurar unos 28 millones de hectareas en los proximos anos. Para cumplir con estas ambiciosas metas, y ademas de aspectos tecnicos, es necesario contar con marcos legales y normativos que habiliten la restauracion del paisaje forestal. El presente informe contiene los resultados de una investigacion que analiza los marcos legales y normativos que regulan la proteccion de los bosques y aquellas actividades restaurativas del paisaje forestal, en 17 paises de America Latina. Se empleo un analisis sistematico del contenido y el alcance de los marcos legales relevantes en materia forestal a nivel de pais en base a una serie de indicadores predefinidos. Ademas se realizo un analisis de percepciones de actores publicos y privados acerca de la implementacion de tales marcos legales. Se encontro una marcada heterogeneidad en la region latinoamericana con respecto al contenido, la estructura y el grado de implementacion de los marcos legales y normativos relacionados al recurso forestal. Esto debido, principalmente, a diferencias en la arquitectura institucional, capacidades humanas, y la presencia o ausencia de incentivos financieros. Los resultados de este analisis revelan tanto oportunidades como desafios para implementar de forma exitosa la restauracion de paisajes forestales en Latinoamerica desde una dimension regulatoria.

Given that few ecosystems on the Earth have been unaffected by humans, restoring them holds great promise for stemming the biodiversity crisis and ensuring ecosystem services are provided to humanity. Nonetheless, few studies have documented the recovery of ecosystems globally or the rates at which ecosystems recover. Even fewer have addressed the added benefit of actively restoring ecosystems versus allowing them to recover without human intervention following the cessation of a disturbance. Our meta-analysis of 400 studies worldwide that document recovery from large-scale disturbances, such as oil spills, agriculture and logging, suggests that though ecosystems are progressing towards recovery following disturbances, they rarely recover completely. This result reinforces conservation of intact ecosystems as a key strategy for protecting biodiversity. Recovery rates slowed down with time since the disturbance ended, suggesting that the final stages of recovery are the most challenging to achieve. Active restoration did not result in faster or more complete recovery than simply ending the disturbances ecosystems face. Our results on the added benefit of restoration must be interpreted cautiously, because few studies directly compared different restoration actions in the same location after the same disturbance. The lack of consistent value added of active restoration following disturbance suggests that passive recovery should be considered as a first option; if recovery is slow, then active restoration actions should be better tailored to overcome specific obstacles to recovery and achieve restoration goals. We call for a more strategic investment of limited restoration resources into innovative collaborative efforts between scientists, local communities and practitioners to develop restoration techniques that are ecologically, economically and socially viable., National Science Foundation, German Helmholtz Centre for Environmental Research—UFZ, Leipzig (Research Program ‘Terrestrial Environments'), sDiv, the Synthesis Centre of the German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig (German Research Foundation), Northern Illinois University

Summary Current efforts to restore and create ecosystems require greater understanding of ecosystems’ responses to commonly used physical and biological intervention approaches to overcome ecological and technological limitations. We estimated effect sizes from measurements of biotic assemblage structure and biogeochemical functions at 628 restored and created wetlands globally, in comparison with 499 reference wetlands. We studied the recovery trajectories of wetlands where different restoration or creation approaches were used under different environmental settings. Although the variance explained by a linear mixed-effects models was low (6–7%), the study of recovery trajectories showed that the restoration or creation approach had no significant effects in most environmental settings. In particular, wetlands where surface modification and flow re-establishment were used followed similar recovery trajectories regardless of whether they were revegetated or not. We even found potential detrimental effects of biological manipulations on the recovery of the plant assemblage, particularly in cold climates and in wetlands restored or created in agricultural areas. Since physical interventions are required to recover or create the hydrological conditions of degraded or new wetlands, and given the high cost (22–73%) of biological interventions (i.e. revegetation), the need for biological interventions is, in most cases, unclear. Our results highlight the urgent need to increase our understanding of the long-term effects of restoration and creation actions in our aim to engage in large-scale ecosystem management strategies for wetlands. Synthesis and applications. These results suggest that, currently, the recovery and development processes of restored and created wetlands can be driven by spontaneous processes rather than by the response of wetlands to human interventions other than those targeted to restore hydrological conditions that existed prior to disturbance. However, given the synthetic nature of the data set, the mixed nature of available data and the limited number of measures we found to estimate recovery, caution must be exercised when adapting the results presented here to the planning and execution of specific ecosystem restoration projects.

Understanding social perceptions of rural communities is essential to construct public policy and management alternatives, not only to maintain natural ecosystems but also to deal with a changing environment due to climatic change. Because climate variability in Mexico has important socio-economic and environmental impacts, it is necessary to build capacities for adaptation. We describe social perceptions of three main local stakeholders (that is, farmers, elders, and local authorities), regarding their relationships with rainforest and local adaptation to climate change in eleven rural communities in Marques de Comillas municipality, Chiapas, Southern Mexico. We based in a qualitative approach and used participant observation and semi-structured interviews. Even certain subtly variation among stakeholders, we recognized some underlying ideas behind perceptions. Rainforest is considered crucial to maintain human livelihoods and to mitigate climatic changes. They perceived changes in climate occurring in the region, such as raising temperature, unpredictable rainfall, and streams becoming dry. Local organization and government involved in managing rainforest or dealing with climatic changes are practically absent. This emphasizes the needs bring proper and reliable information to make decisions regarding rainforest use and management, but also to adapt to a changing climate. The loss of the collective character of the communities and, certain conflicts in public policies that mirrored in the coexistence of initiatives with contrasting objectives are proposed as particularly important for understanding the emergence of these perceptions. We proposed some recommendations to bolster regional capacities addressing climate change. Involving stakeholders such as governmental and non-governmental institutions is also imperative.

La restauración ecológica se utiliza a menudo para recuperar los niveles de biodiversidad y de servicios ecosistémicos (SE) en ecosistemas degradados. En general, los resultados de la restauración ecológica se pueden estimar como el progreso o la compleción de la recuperación de indicadores de la integridad ecológica en el estado restaurado respecto al estado degradado o de referencia, respectivamente. Presentamos una síntesis de estos resultados según cuatro meta-análisis globales independientes, obtenidos en una amplia gama de ecosistemas, con énfasis en humedales, agroecosistemas y bosques. La restauración ecológica aumentó la biodiversidad y los SE en 58 y 99%, respectivamente. Sin embargo, estos niveles fueron inferiores a los de los ecosistemas de referencia (-10 y -8%, respectivamente). La recuperación varió entre tipos de ecosistema. Los humedales restaurados tuvieron niveles más altos de biodiversidad y de SE (19 y 43%, respectivamente) en relación a los degradados, aunque los niveles de los SE fueron inferiores (-13%) a los de referencia. La restauración aumentó los niveles de biodiversidad, SE de soporte y SE de regulación de los agroecosistemas en 68, 42 y 120%, respectivamente, y los agroecosistemas restaurados tuvieron niveles de biodiversidad y de estos SE similares a los ecosistemas de referencia. En el caso de los bosques, la recuperación fue completa para todos los SE, mientras que la biodiversidad, aunque aumentó 106% después de la restauración, fue 21% inferior a los niveles de referencia. Existe un hueco en la literatura científica sobre la evaluación cuantitativa de los SE culturales en ecosistemas restaurados. La recuperación de la biodiversidad y de los SE se correlacionaron de forma positiva en las comparaciones de ecosistemas degradados y restaurados en todos los meta-análisis. Concluimos que la restauración ecológica aumenta de forma notable la biodiversidad y los SE, aunque no se alcanzan los niveles de los ecosistemas de referencia, Comunidad de Madrid, Fondo para la Investigación Científica y Tecnológica (Argentina)

We contrasted regulatory instruments to govern riparian forest restoration in Mexico and Brazil. Overall, Mexico has a few regulatory instruments covering the protection and restoration of riparian buffers but no specific instrument to operationalize restoration demands, while Brazil has objective norms supporting the restoration of riparian forests. Benchmarking regulatory frameworks from other countries can be a valuable approach for supporting the governance of riparian forest restoration.

Global forest restoration targets have been set, yet policy makers and land managers lack guiding principles on how to invest limited resources to achieve them. We conducted a meta-analysis of 166 studies in naturally regenerating and actively restored forests worldwide to answer: (1) To what extent do floral and faunal abundance and diversity and biogeochemical functions recover? (2) Does recovery vary as a function of past land use, time since restoration, forest region, or precipitation? (3) Does active restoration result in more complete or faster recovery than passive restoration? Overall, forests showed a high level of recovery, but the time to recovery depended on the metric type measured, past land use, and region. Abundance recovered quickly and completely, whereas diversity recovered slower in tropical than in temperate forests. Biogeochemical functions recovered more slowly after agriculture than after logging or mining. Formerly logged sites were mostly passively restored and generally recovered quickly. Mined sites were nearly always actively restored using a combination of planting and either soil amendments or recontouring topography, which resulted in rapid recovery of the metrics evaluated. Actively restoring former agricultural land, primarily by planting trees, did not result in consistently faster or more complete recovery than passively restored sites. Our results suggest that simply ending the land use is sufficient for forests to recover in many cases, but more studies are needed that directly compare the value added of active versus passive restoration strategies in the same system. Investments in active restoration should be evaluated relative to the past land use, the natural resilience of the system, and the specific objectives of each project.

Los bosques ribereños albergan una biodiversidad importante y en ellos se desarrollan funciones ecológicas esenciales que repercuten en la provisión de servicios ecosistémicos relevantes para la sociedad. Las perturbaciones de origen antrópico frecuentemente exceden la resiliencia natural de estos ecosistemas y, en consecuencia, desencadenan procesos de degradación. La restauración ecológica busca recuperar la biodiversidad y los servicios de los bosques ribereños, pero su éxito depende de varios aspectos de contexto. En este trabajo se utiliza un estudio de caso para ejemplificar la problemática de la restauración desde una perspectiva 'integral' y se discuten aspectos ecológicos, socio-económicos y legales que pueden influir en el éxito de la restauración de estos bosques. Si bien los aspectos ecológicos han sido considerablemente desarrollados, aún falta información relacionada con las limitaciones económicas (p. ej. los costos de producción), sociales (p. ej. la aceptación social) y legales (p.ej. la incorporación de la restauración ecológica en programas públicos), para ser aplicados a escalas más amplias. La estimación de los servicios ecosistémicos que podrían restablecerse a partir de la restauración de bosques ribereños aportará a la integración de estos aspectos. El abordaje de estos aspectos a escala local aportará información para el desarrollo futuro de estrategias a escala regional más eficientes en términos de la relación beneficio ecológico-costo socioeconómico. Se discuten algunas recomendaciones relacionadas con la conservación, el manejo y la restauración de los bosques ribereños en el trópico húmedo de México., Riparian ecosystems harbor significant biodiversity and support essential ecological functions that affect ecosystem services provision for human well-being. Anthropogenic disturbances often exceed the natural resilience of these ecosystems thus resulting in their degradation. Ecological restoration promotes restoring biodiversity and riparian ecosystems services, but its success depends on several aspects. This work bases on a study case to exemplify the problem of restoration from an ‘integral’ perspective and discusses ecological, socio-economic and legal aspects that can influence the success of the restoration of these forests. While ecological aspects have been considerably developed, information on economic (e.g. production costs), social (e.g. social acceptance) and legal constraints (e.g. incorporation of restoration in public programs) are still limited for restoration being applied at broader scales. Estimating ecosystem services that could be restored from the restoration of riparian forests may help to integrate these aspects. Addressing these aspects at the local level will provide information for the future development of more efficient regional strategies in terms of the ecological benefit-socioeconomic cost ratio. Finally, we discuss some recommendations relating to the conservation, management and restoration of riparian ecosystems in the humid tropics of Mexico., Fundación Rufford

Question: How to evaluate and integrate relevant ecological, social and techni- cal criteria to select species to be introduced in restoration projects of highly diverse ecosystems such as tropical riparian forests. Location: Riparian forest, Marqude Comillas municipality, southeast Mexico (16°54'N, 92°05'W). Methods: We proposed a 'species selection index' (SSI) using five independent criteria related to ecological, social and technical information. SSI targeted spe- cies that (1) are important in the reference forest; (2) are less likely to establish following disturbance; (3) are not specific to a particular habitat; (4) are socially accepted; and (5) their propagation requires a reasonable time and financial investment. SSI may range between zero and 50, with higher values meaning higher potential for restoration purposes. Results: Out of a local pool of 97 species, we identified 30 target tree species that together represented >60% of total importance value index in the reference riparian forests. SSI averaged 28.3 1.0 over the studied species, suggesting that species with high values are not frequent. For 20 species, reintroduction by means of active forest restoration was deemed necessary. Species that estab- lished through natural regeneration, following secondary regrowth, had lower social value among local farmers. Nearly half of the identified species showed technical constraints for easy propagation and seeding. Conclusions: The proposed procedure is useful for selecting species to initiate forest restoration projects and of other woody ecosystems that harbour high bio- diversity, and is suitable for several stakeholders interested in restoration.

The large-scale forest restoration pledges made by many Latin American countries are expected to be mostly implemented in rural areas, where competition for land with agriculture and lack of farmer engagement may prevent forest expansion. Planning for forest restoration actions must combine policy-driven approaches ( top-down ) that set national and regional targets, with site-specific objectives based on the socio-political context and local needs ( bottom-up ). Here we present five case studies from projects in Latin America that were conducted in different social and legal contexts, but shared the use of riparian-forest buffers as a focal point for forest restoration in rural landscapes. These cases illustrate how focusing on riparian buffers may help bridge top-down and bottom-up approaches when planning forest restoration in rural landscapes of Latin America. In some cases, restoration actions were motivated by economic incentives and legal compliance whereas in others they were driven by societal demands. We propose that riparian forest buffers deserve special consideration as a suitable place to begin bridging the gap between national-scale restoration commitments and local-scale use and production needs, while facilitating the participation of all stakeholders in both the planning and implementation processes.

Recent progress in the ecosystem services (ES) approach has been made through the application of integrated valuations of ecosystem services (IVES), which emphasizes social inclusion and incorporates a plurality of values in ES valuations. Given that most of the empirical experience with IVES practice has been in the Global North, we need to understand this practice in other contexts such as the Global South and Latin America. Based on 21 studies that applied IVES approaches, we evaluated how IVES is being implemented in socio-ecological contexts in Latin America and the challenges and ways forward for implementing it in this region. Leaders of the case studies completed a questionnaire that addressed these questions based on an analytical framework. Our case studies demonstrated advances in: integrating socio-cultural and monetary valuations, developing interdisciplinary and transdisciplinary approaches, communicating results, and providing policy recommendations that go beyond economic incentives. However, more efforts are still needed to engage some of the social actors, integrate ecological values, and address value trade-offs and power relations. Challenges and ways forward for implementing IVES approaches can be grouped into five areas: (i) building a culture of transdisciplinary research; (ii) promoting holistic versus split disciplinary valuations; (iii) engaging with environmental and civil society organizations and local leaders; (iv) supporting less powerful social actors and bringing out their voices through the IVES process; and (v) generating new means of communicating multiple perspectives at multiple scales. Our study empirically shows how new paths in socio-ecological contexts in Latin America are opening up to include the complex, conflicting, and diverse views of the importance of nature. We believe that in Latin America, IVES could be framed as participatory action research that empowers less powerful social actors through transdisciplinary and participatory valuation approaches.

Global initiatives such as the Aichi Targets and Bonn Challenge have inspired governments to pledge to restore millions of hectares of degraded lands. Many of these calls to action and policy frameworks identify capacity development as important for implementing and scaling-up restoration activities to meet global targets. However, there is little explanation about what capacity development actually involves. How is capacity development approached in the context of restoration? What makes it more or less effective? This article aims to help fill that gap by identifying four components of what an effective approach to capacity development might look like, drawing upon a number of examples in practice. We believe that capacity development initiatives can more effectively support stakeholders to address the complex nature of forest landscape restoration (FLR) if they include the following four components: (a) activities tailored to stakeholder needs and context, (b) knowledge and applied experience from diverse sources and disciplines, (c) skill sets for selecting among a suite of restoration interventions, and (d) inclusion of multiple subjects and skill sets (e.g., social, financial, legal, etc.) in addition to technical or ecological themes. As exemplified by the organizations discussed in this article, these four elements of capacity development can help to support restoration professionals and other stakeholders to think holistically, moving from the scale of an individual farm or plot to the landscape scale where they must address more diverse stakeholder interests, societal trade-offs, and socioecological heterogeneity. This more holistic approach to FLR planning and implementation is needed to more effectively accomplish ambitious FLR targets worldwide.

Question: Does the presence of grasses affect the establishment (survival and growth) of treesaplingsin an abandoned tropical pasture, and what isthe potential of established saplings to modify pasture microenvironmental conditions, particularly light incidence? Location: Abandoned cattle pasture, in the humid tropics of SE Mexico (18°25′ –18°45′ N, 95°00′–95°18′ W). Methods: The establishment of four native fast-growing tree species in a tropical abandoned pasture was evaluated. Saplings of Cecropia obtusifolia, Hampea nutricia, Omphalea oleifera and Erythrina folkersii were transplanted using a split-plot design. Plant survival and growth were evaluated over 12 mo under two experimental treatments: presence and absence of grasses. Light incidence at ground level was used to evaluate microclimate conditions under the grass matrix, compared to light incidence under saplings established in the pasture. Results: Saplings had high survival (49–88%) regardless of the presence of grasses. In the presence of grasses, growth of surviving saplings either increased or was not impacted, and in only one out of eight comparisons did grasses negatively affect growth. The impact of saplings on light incidence in abandoned pastures depended on sapling species architecture: species with large total leaf area and canopy area (H. nutricia and E. folkersii )s ignif icantly reduced light incidence (12–29% of total incidence), while narrow-canopy species (C. obtusifolia and O. oleifera) generated less intense shade (37–89% of total incidence). Conclusions: Grasses did not seem to represent a crucial limiting factor in sapling establishment of fast-growing native species in the short term. In addition, shading by recruited saplings of some native species could be important to outcompete grasses in the future, as well as for ‘facilitating’ regeneration of more shade-tolerant species. Transplantation of fast-growing native saplings into abandonedpastures,even without manipulation of the grasses,could bea useful practice for landscape-scale restoration programmes in tropical areas. Evaluation of the longer-term consequences (beyond the 1-yr span of this study) warrants further research.

Los apéndices, tablas y figuras que contiene el documento se localizan al final del mismo., Landscape transformation due to agriculture affects more than 40% of the planet’s land area and is the most important driver of losses of biodiversity and ecosystem services (ES) worldwide. Ecological restoration may significantly reduce these losses, but its effectiveness has not been systematically assessed in agroecosystems at the global level. We quantitatively meta-analyzed the results of 54 studies of how restoration actions reflecting the two contrasting strategies of land sparing and land sharing affect levels of biodiversity and ES in a wide variety of agroecosystems in 20 countries. Restoration increased overall biodiversity of all organism types by an average of 68%. It also increased the supply of many ES, in particular the levels of supporting ES by an average of 42% and levels of regulating ES by an average of 120% relative to levels in the pre-restoration agroecosystem. In fact, restored agroecosystems showed levels of biodiversity and supporting and regulating ES similar to those of reference ecosystems. Recovery levels did not correlate with the time since the last restoration action. Comparison of land sparing and land sharing as restoration strategies showed that while both were associated with similar biodiversity recovery, land sparing led to higher median ES response ratios. Passive and active restoration actions did not differ significantly in the levels of biodiversity or ES recovery. Biodiversity recovery positively correlated with ES recovery. We conclude that ecological restoration of agroecosystems is generally effective and can be recommended as a way to enhance biodiversity and supply of supporting and regulating ES in agricultural landscapes. Whether a land sharing or land sparing strategy is preferable remains an open question, and might be case dependent. Moreover, it is unclear whether crop production on restored land can meet future food production needs., Comunidad de Madrid, Comisión Interministerial de Ciencia y Tecnología-CICYT

A linear engineering project—i.e. a pipeline—has a potential long- and short-term impact on the environment and on the inhabitants therein. We must find better, less expensive, and less time-consuming ways to obtain information on the environment and on any modifications resulting from anthropic activity. We need scientifically sound, rapid and affordable assessment and monitoring methods. Construction companies, industries and the regulating government organisms lack the resources needed to conduct long-term basic studies of the environment. Thus there is a need to make the necessary adjustments and improvements in the environmental data considered useful for this development project. More effective and less costly methods are generally needed. We characterized the landscape of the study area, situated in the center and north–east of Argentina. Little is known of the ecology of this region and substantial research is required in order to develop sustainable uses and, at the same time, to develop methods for reducing impacts, both primary and secondary, resulting from anthropic activity in this area. Furthermore, we made an assessment of the environmental impact of the planned linear project, applying an ad hoc impact index, and we analyzed the different alternatives for a corridor, each one of these involving different sections of the territory. Among the alternative corridors considered, this study locates the most suitable ones in accordance with a selection criterion based on different environmental and conservation aspects. We selected the corridor that we considered to be the most compatible—i.e. with the least potential environmental impact—for the possible construction and operation of the linear project. This information, along with suitable measures for mitigating possible impacts, should be the basis of an environmental management plan for the design process and location of the project. We pointed out the objectivity and efficiency of this methodological approach, along with the possibility of integrating the information in order to allow for the application thereof in this type of study.

In revegetation projects, distinguishing species that can be passively restored by natural regeneration from those requiring active restoration is not a trivial decision. We quantified tree species dominance (measured by an importance value index, IVIi) and used abundance‐size correlations to select those species suitable for passive and/or active restoration of disturbed riparian vegetation in the Lacandonia region, Southern Mexico. We sampled riparian vegetation in a 50 ×10‐m transect in each of six reference (RE) and five disturbed (DE) riparian ecosystems. Those species representing more than 50% of total IVI in each ecosystem were selected, and Spearman rank correlation between abundance and diameter classes was calculated. For eight species, it was determined that passive restoration could be sufficient for their establishment. Another eight species could be transplanted by means of active restoration. Five species regenerate well in only one ecosystem type, suggesting that both restoration strategies could be used depending on the degree of degradation. Finally, two species were determined to not be suitable for restoration in the RE (based on the above selection criteria) and were not selected during this initial stage of our restoration project. The high number of tree species found in the RE suggests that the species pool for ecological restoration is large. However, sampling in both ecosystem types helped us reduce the number of species that requires active restoration. Restoration objectives must guide the selection of which methods to implement; in different conditions, other criteria such as dispersal syndrome or social value could be considered in the species selection.

Tropical regions hold the planet´s most biodiverse ecosystems. Despite its importance to biodiversity and conservation, anthropogenic activities are degrading these ecosystems, with unknown consequences for its functioning and structure. In between the several ecosystems through the tropics, freshwater ecosystems call attention, due to its small fraction of area comparing to terrestrial ecosystems, that represent an enormous importance for human surviving and developing. Headwater streams constitute the majority of water bodies in a catchment, and therefore, it is essential for the health of the entire freshwater ecosystems. Several headwater streams are inserted in agricultural lands, suffering from the pressures from agricultural intensification. Therefore, this thesis was developed aiming to understand what are the main pressures that tropical headwater streams has been suffering, worldwide and locally in the Corumbataí river basin. The first chapter will contribute to understanding what are the main issues that tropical streams have been experiencing, focusing on agricultural multiple stressors and climate change effects. The second chapter analyzes how the conversion of low-intensity pasturelands to high-intensity bioenergy crops changes the water quality parameters in streams located in the Corumbataí river basin and also examines how important are the riparian forests in the headwater zone to provide better water quality in bioenergy crops. The third chapter investigates how water quality and climatic characteristics affect benthic biofilm community dynamics in tropical headwater streams in the Corumbataí river basin. The results have shown the existence of several knowledge gaps about tropical streams, mainly related to the effects of climate change, multiple stressors and the lack of policies and mitigation strategies for climate change. In relation to water quality, we found that the conversion of low-intensity pastures to high-intensity bioenergy crops are degrading water quality. Riparian forests in the springhead zone have demonstrated to be essential in providing water quality in bioenergy crops, especially in the wet season. The benthic biofilm community seems to be controlled mainly by climate characteristics and not by nutrient availability as observed in temperate streams. Therefore, a climate change scenario, the benthic biofilm will be strongly affected, with consequences in the functioning of tropical headwater streams. To reduce the negative impacts of intensive agriculture and climate change, we recommend the implementation of riparian forests, with special attention to the springhead area and also the implementation of best agricultural practices in tropical agriculture to ensure the sustainability of tropical freshwater resources. As regiões tropicais possuem os ecossistemas mais biodiversos do planeta. Apesar da sua importância na manutenção da biodiversidade, as atividades antrópicas estão degradando esses ecossistemas, gerando consequências negativas para sua estrutura e funcionamento. Entre os diversos ecossistemas tropicais, as águas doces chamam a atenção por ocupar uma pequena área em comparação com ecossistemas terrestres, porém, representam grande importância para a sobrevivência e desenvolvimento humano. Os riachos de cabeceira representam a maior parte dos corpos aquáticos em uma microbacia e, portanto, sua conservação é essencial para a saúde de toda a rede de drenagem de água doce. Diversos riachos de cabeceira estão inseridos em ecossistemas agrícolas, sofrendo as consequências da agricultura intensiva. Nesse sentido, esta tese foi desenvolvida com o intuito de entender quais são os principais impactos que os riachos de cabeceira tropicais vêm sofrendo, globalmente e localmente na bacia do rio Corumbataí (SP, Brasil). O primeiro capítulo contribui para entender quais os principais problemas que riachos tropicas estão sofrendo, focando nos múltiplos estressores advindos da agricultura e efeitos de mudanças climáticas. O segundo capítulo analisa como a conversão de pastos para cultivo de cana de açúcar modifica a qualidade da água em riachos da bacia do rio Corumbataí e também analisa o quão fundamentais são as florestas nas áreas de nascente para manter a qualidade da água em plantios de cana de açúcar. O terceiro capítulo analisa como a qualidade da água e características climáticas influenciam biofilmes bentônicos em riachos de cabeceira na bacia do rio Corumbataí. Os resultados demonstraram a existência de diversos tópicos que necessitam de maior entendimento, principalmente relacionados às mudanças climáticas e estressores múltiplos e a falta de políticas e estratégias de mitigação para os efeitos de mudanças climáticas. Em relação à qualidade da água, demonstrou-se que a conversão de pastos para cultivo de cana de açúcar reduz a qualidade da água. A presença de florestas nas nascentes demonstrou ser essencial na manutenção da qualidade da água em plantios de cana. Os biofilmes bentônicos demonstraram ser controlados principalmente por características sazonais e não pela disponibilidade de nutrientes como observado em riachos temperados. Portanto, essa comunidade será severamente afetada diante das mudanças climáticas, com consequências no funcionamento de riachos de cabeceira tropicais. Para reduzir os efeitos negativos da agricultura intensiva e das mudanças climáticas, recomenda-se a implementação de florestas ripárias, com especial atenção às áreas de nascentes. Também se recomenda a implementação de boas práticas agrícolas na agricultura para garantir a sustentabilidade dos recursos hídricos tropicais.