Developed by the IAI Collaborative Research Network for the study of Tropical Dry Forests in the Americas, Editors: Jafet M. Nassar, Jon Paul Rodríguez, Arturo Sánchez-Azofeifa, Theresa Garvin, Mauricio Quesada.
This book was developed as a manual of methods designed specifically for tropical dry forests with emphasis on the topics included in the IAI project, but it has wide application potential, as the global change questions addressed with these methods are similar to other terrestrial ecosystems. The book describes a wide range of methods: ecological (ecosystem structure, soil microbiology, phenology, biotic interactions), remote sensing (spatial information, image processing), and social science (human-ecosystems relationships, socio-economic indicators, and environmental policy). Emphasis is on the dynamics of the systems investigated, so that the analyses provide a picture of the processes of deterioration and/or recovery of heavily disturbed systems. Download PDF
Tropical dry forests are vulnerable under global change.
This map shows trends in productivity of tropical dry forests of the Americas between 1982 and 2006, derived from satellite images. Changes in productivity in these endangered ecosystems are revealed by phenological variables, such as the beginning of leaf flush and the length of the growing season before leaf fall. Results demonstrate that forests in the Llanos of Venezuela and Colombia, in some Northern Mexican ecoregions, as well as in the Chaco of Argentina and Bolivia have increased their productivity, while other Mexican regions and the Brazilian Caatinga are losing productivity. Both responses are likely a reaction to global warming, which changes the rainfall and moisture regimes and hence, productivity. (The map is based on a vegetation indicator (NDVI) time series derived from a satellite sensor (MODIS GIMMS AVHRR), processed with TIMESAT, a software for phenological season modeling, and a Mann-Kendall statistical trend analysis.)
Only 40% is left of the original extent of tropical dry forests in the Americas. But only 4.5 % of tropical dry forests (23,417 km2) are currently protected in national parks and biological reserves, mostly in Bolivia and Brazil. Other countries, with large, threatened dry forest areas need to better protect their forests. The maps now available help understanding trends in forest growth, identifying the most vulnerable areas and developing regionally adapted responses.
Preservation efforts for tropical dry forests need to address the forests’ multiple benefits. These include the remarkable biodiversity and important ecosystem services. In addition to parks, other protection schemes such as payments to land owners for avoided deforestation are needed, and sustainable land management in tropical dry forests must be supported with economic and fiscal incentives.
Science Snapshots 8 – The Story
The tropics are much more than ‘just’ rainforests. While rainforests receive much attention for being threatened ecosystems, many tropical dry forest areas are under much greater threat. Their open, park-like character has invited extensive colonization. They are seen by many as non-essential ecosystems that can be transformed into agricultural land at no ecological costs. This attitude should change. Tropical dry forests occupy 42% of the tropical forest area worldwide. Their biodiversity is similar to that of rainforests, and they provide hydrological and climate regulation and carbon storage.
In the Americas, tropical dry forests extend over 520,000 km2. Including forests in other arid and semi-arid environments and savanna ecosystems increases the total area of dry forested ecosystems to about 1,070,000 km2, about 12 per cent of the Amazon forest area. Mexico contains the largest portion (38%) of the neotropical dry forest area, with numerous different dry forest ecoregions. Bolivia and Brazil follow. The size of those forest patches matters, as larger contiguous areas preserve the integrity of species assemblages better. On the other hand, the high fragmentation of dry forests in Guatemala, Nicaragua, Ecuador, Costa Rica and Peru represents a higher risk of disturbance and extinction there.
The IAI-supported TROPI-DRY project team, led by Arturo Sánchez-Azofeifa of the University of Alberta, Canada, studied growing season length and productivity in tropical dry forests. Using satellite-based Normalized Difference Vegetation Index (NDVI) time series, they detected statistically significant trends in three phenological variables: length of dry season, length of the growing season, and total productivity. The results show a declining growing season and productivity in some forests, which reduces stand biomass, carbon storage and water retention. This trend may be linked to global warming, and could lead to considerable pressure on water resources for agriculture and tourism in Northeastern Brazil and Southern Mexico. It could also result in more forest fires, desertification, habitat loss and species migration. If land cover changes occur over large areas, this can affect the regional climate because cooling mechanisms such as evapo-transpiration and albedo (reflectance) from vegetation are weakened. Extensive droughts, attributed to this effect, have recently been observed in Mexican tropical dry forest regions.
In contrast, dry forests in Venezuela, Bolivia, Paraguay, Argentina and Northern Mexico showed a longer growing season and increased productivity. This may on first sight seem positive, but the scientists are concerned that higher productivity may invite land users to intensify agriculture and deforestation. Such landuse changes may initiate desertification processes, resulting in the spread of cactus and agave species in former forest areas.
Productivity will be an important aspect to be considered if REDD+ schemes (international agreements to Reducing Emissions from Deforestation and Degradation in Developing Countries) are to be realized. But as these forests provide important ecosystem services, the benefits of protecting tropical dry forests go far beyond carbon sequestration. Multiple forest uses have to be harmonized through ecological payment schemes and sustainable land management if conservation is to be successful. Furthermore, land management outside of reserves and parks needs to become more sustainable, to protect, maintain and enhance ecosystem functioning also in those areas.
Espírito-Santo, M. M., A. C. Sevilha, F. C. Anaya, and colleagues (2009). Sustainability of tropical dry forests: Two case studies in southeastern and central Brazil. Forest Ecology and Management. Vol. 258(6), pages 922-930.
Portillo-Quintero, C. A., and G. A. Sánchez-Azofeifa (2010). Extent and conservation of tropical dry forests in the Americas. Biological Conservation. Vol. 143(1), pages 144-155.
Quesada, M., G.A. Sanchez-Azofeifa, M. Alvares, and colleagues (2009). Succession and management of tropical dry forests: Synthesis and new perspectives. Forest Ecology and Management. Vol. 258(6), pages 1014-1024.
Science Snapshots are intended to inform IAI clients and the interested public about important results of international Global Change research carried out under IAI auspices. Editorial Board: Christopher Martius, Ione Anderson, Paula Richter, Holm Tiessen Design: Shadi Ardalan Cite as: IAI (2011): Gains and losses: Tropical dry forests are vulnerable under global change. Science Snapshots 8 Funded by IAI, NSF under CRN 2021.
This is a summary of the most salient project results. For further information see the project website, project papers or contact the investigators directly.
This project conducts a knowledge synthesis on ecosystem services in tropical dry forest (TDF), using literature and data from previous CRN 2021 and SGP-CRA 2021 projects, models of land use and cover change, and provides knowledge exchange with stakeholders in Costa Rica and Brazil.
Of 531 articles on ecosystem services (1970 to 2015), 47% are related to biodiversity, 26% to carbon, 16% to soils, and only 11 % to water. Studies of biodiversity and carbon focused specifically on provisioning services, studies of water focused on regulating services, and studies of soil focused on supporting services. Information is being integrated using the Dinamica EGO land use change and environmental modeling platform.
Working with IBM analytics to integrate C and water fluxes for the Santa Rosa National Park provided drought prediction tools for Guanacaste, Costa Rica. New wireless sensor networks now monitor cash crops of coffee and sugar cane showing that 80% of the 11,000 coffee farms in Guanacaste were under stress from climate change and the 2014-15 drought.
The wireless sensor network recording intra- and inter-annual variation in forest productivity showed that dry forests recovering from disturbance quickly reestablish their climatic buffer capacity, an important ecosystem service. The canopy-understory climate moderation is related to forest structure and soil properties in addition to light interception. This is important for grazing uses. Forest recovery was aided by remaining fragments of mature and old growth forest in disturbed biomes.
Remote sensing detected intensifying, persistent and new deforestation hotspots on the Southern Pacific coast and Yucatan Peninsula in Mexico, Northwestern Guatemala, in Honduras and around Lake Nicaragua. TDF are already endangered due to a long history of human disturbances but management will become an even greater challenge as drought severity and frequency increase.
These sites are under the political jurisdiction of local environmental authorities. The team provided information that it is more effective to locate parks and sites for ecosystem service payments distant from each other. High levels of enforcement in parks and lands with payments, and the presence of conservation spillovers that reduce deforestation near parks, significantly reduce the potential impact of combining these two policies.
The largest irrigated perimeter in Latin America, with 100,000 ha is being established in Minas Gerais for large multinational fruit producers. For this, the development banks required compensation through the creation of 5 Conservation Units from which traditional communities were expelled in a land-sparing strategy: the segregation of land for intensive agricultural production and land for untouched nature.
However, traditional communities aim at an opposite land-sharing: environmental-friendly farming with low-intensity production and conservation on the same land. The team mapped the territories of these traditional communities so that they can be expropriated inside farms and CUs, and provided technical information to the Environmental Attorney to transform 5,000 ha of the 25,000 ha CU into a sustainable use regime.
Ranching is an important part of agricultural production in South America. Although there are more than 40 million hectares of degraded pastures in the region, silvo-pastoral systems can sustainably maintain both an economic activity, and near intact ecosystems and their services. We here present examples from the Argentine Chaco and the dry forests of Minas Gerais, Brazil. This movie is based on the results of the research of this project and climate, water and land-use decisions in the plains of Southern South America (SGP-CRA 2031)
Interview with Arturo Sanchez Azofeifa on tropical dry forest responses to climate change and likely future changes. RTCC – UNFCCC CoP20, Lima, Peru, December 2014
IAI-Environet is a practical solution to climate change challenges. Climate change affects the resilience of dry forest ecosystems. To work towards comprehensive climate change adaptation policies in arid and semi-arid regions of the Americas we need to monitor and understand interactions between forests and their environment. Arturo Sanchez-Azofeifa (IAI) presents an advanced wireless sensor and analytics system designed to collect and analyze environmental data. The Enviro-Net system is already active in several countries and will be installed in Peru in 2015. November 2014.
2014, June. UNFCCC, Sixth meeting of the research dialogue at SBSTA 40 (RD6), Bonn. A. Sanchez-Alzofeifa, Tropical Dry Forest Resilience and Water Use Efficiency Tropical dry forests: barometers of climate change.
2013, June. UNFCCC, Research Dialogue 5, SBSTA 38, Bonn. A. Sanchez-Alzofeifa, Carbon fluxes in tropical dry forests and savannas: Human, ecological and biophysical dimensions
Arturo Sánchez-Azofeifa (gasanche_AT_ualberta.ca)
University of Alberta (Canada)
Julio Calvo-Alvarado (jucalvo_AT_itcr.ac.cr)
Instituto Tecnológico de Costa Rica, Costa Rica
Mário Marcos do Espírito Santo (marioesanto_AT_gmail.com)
Universidade Estadual de Montes Claros, Brazil
Texas Tech University, USA
Juan Andres Robalino
Centro Agronómico de Investigación y Enseñanza (CATIE), Costa Rica
Economic Commission for Latin America and the Caribbean (ECLAC), Chile
Adrian Araya, Undergraduate, Instituto Tecnológico de Costa Rica, Costa Rica
Alline Mendes Alves, Master, Universidade Estadual de Montes Claros, Brazil
Amanda Elisa Marega, Undergraduate, Universidade Federal do Rio de Janeiro, Brazil.
Ana Carolina Lima Finoti, Undergraduate, Universidade Federal Rural do Rio de Janeiro, Brazil.
Ana Cecilia Pancotti, Undergraduate, Universidade Federal do Rio de Janeiro, Brazil.
Ana Julieta Calvo Obando, Master, Instituto Tecnológico de Costa Rica, Costa Rica.
André Rocha, Master, Universidade Estadual de Montes Claros, Brazil.
Andrea Tapia Arenas, Undergraduate, Instituto Tecnológico de Costa Rica, Costa Rica.
Andrés Calderín Garcia, PHD, Universidade Federal Rural do Rio de Janeiro, Brazil.
Brad Danielson, Post Doctorate, University of Alberta, Canada.
Branko Hilje, PHD, University of Alberta, Costa Rica.
Camila Pinheiro Nobre, PHD, Universidade Federal Rural do Rio de Janeiro, Brazil.
Cao Sen, PHD, University of Alberta, China.
Cassidy Rankine, PHD, University of Alberta, Canada.
Catalina Sandoval, Master, Universidad de Costa Rica, Costa Rica.
Crystine Skinner, Undergraduate, University of Alberta, Canada.
David Sanchez, Undergraduate, Instituto Tecnológico de Costa Rica, Costa Rica.
Diego Roman, Master, CATIE, Costa Rica.
Domina Harrison, Undergraduate, University of Alberta, Canada.
Elena Garcia, Undergraduate, Universidad Politecnica de Valencia, Spain.
Elizabeth Jimenez, Undergraduate, Instituto Tecnológico de Costa Rica, Costa Rica.
Eric Ribeiro Madureira, Master, Universidade Estadual de Montes Claros, Brazil.
Erick Naranjo Esquivel, Undergraduate, Instituto Tecnológico de Costa Rica, Costa Rica.
Ezequiel Fallas, Undergraduate, Instituto Tecnológico de Costa Rica, Costa Rica.
Flávio M. Mota, Undergraduate, Universidade Estadual de Montes Claros, Brazil.
Francy Gonçalves, PHD, Universidade Federal Rural do Rio de Janeiro, Brazil.
Frederico Almeida Macedo, Undergraduate, Universidade Estadual de Montes Claros, Brazil.
Graciane Siqueira Correa, Undergraduate, Universidade Estadual do Rio de Janeiro, Brazil.
Helen Botelho Marota, Master, Universidade Federal Rural do Rio de Janeiro, Brazil.
Helen Rosa, Master, Universidade Estadual de Montes Claros, Brazil.
Jing Chen, PHD, University of Alberta.
Joselandio Correa Santos, Undergraduate, Universidade Estadual de Montes Claros, Brazil.
Kayla Stan, Master, University of Alberta, Canada.
Kênia Mendes Dias, Master, Universidade Federal Rural do Rio de Janeiro, Brazil.
Kléber de Oliveira Fernandes, Master, Universidade Estadual de Montes Claros, Brazil.
Laura Giovanna Oliveira Lopes, Master, Universidade Estadual de Montes Claros, Brazil.
Lidong Zhu, PHD, University of Alberta, China.
Lucas Figueiredo, Undergraduate, Universidade Estadual de Montes Claros, Brazil.
Luiz Gilberto Ambrósio de Souza, Master, Universidade Federal Rural do Rio de Janeiro, Brazil.
Marco Túlio Santos Vieira, Undergraduate, Universidade Estadual de Montes Claros, Brazil.
Maria Betânia Fonseca, Master, Universidade Estadual de Montes Claros, Brazil.
Maria Fernanda Gonçalves Durães, Undergraduate, Universidade Estadual de Montes Claros, Brazil.
Mariajose Esquivel, Undergraduate, Instituto Tecnológico de Costa Rica, Costa Rica.
Mariana Guimarães Dupin, Undergraduate, Universidade Estadual de Montes Claros, Brazil.
Mariana Vargas Coto, Undergraduate, Instituto Tecnológico de Costa Rica, Costa Rica.
Maryangel Gonzalez, Undergraduate, Instituto Tecnológico de Costa Rica, Costa Rica.
Mike Hesketh, PHD, University of Alberta, Canada.
Norberto Ramirez, Undergraduate, Instituto Tecnológico de Costa Rica, Costa Rica.
Ozorino Neto, Master, Universidade Estadual de Montes Claros, Brazil.
Pablo Ruiz Gimenez, Undergraduate, Universidad Politecnica de Valencia, Spain.
Patrick Fonseca, Undergraduate, Universidade Estadual de Montes Claros, Brazil.
Paulo Augusto Binder D’Angelis, Master, Universidade Estadual de Montes Claros, Brazil.
Riard Porto, Undergraduate, Universidade Estadual de Montes Claros, Brazil.
Sael Sánchez Eliaz, PHD, Universidade Federal Rural do Rio de Janeiro, Brazil.
Sandra Duran, PHD, University of Alberta, Colombia.
Sarah Freitas Magalhães Silva, Master, Universidade Estadual de Montes Claros, Brazil.
Saulo Castro Contreras, PHD, University of Alberta, Mexico.
Shawna Stack, Undergraduate, University of Alberta, Canada
Sofia Calvo Rodriguez, Master, University of Alberta, Costa Rica.
Thiago Gonçalves Silva, Master, Universidade Estadual de Montes Claros, Brazil.
Vaughn Smith, Undergraduate, Texas Tech University, USA.
Virginia Garcia Millan, Post Doctorate, Spain.
Wei Li, PHD, University of Alberta, China.
Wendy Alvarado, Undergraduate, Instituto Tecnológico de Costa Rica, Costa Rica.
Wesley Silveira Marcelo Soares, Undergraduate, Universidade Estadual de Montes Claros, Brazil.
Zhujun Gu, Post Doctorate, University of Alberta, China
Tropical Dry Forests (TDFs) are considered one of the most threatened forest ecosystems in the world as a consequence of intensive anthropogenic disturbance. Their fertile soils and mild climates make them highly suitable for conversion to agriculture and livestock. Given their attractive environmental characteristics for human settlement and development, this ecosystem has historically supported extensive deforestation. Despite TDF’s remarkable richness of species (including endemic species), the vital role its ecosystem services provide for extensive and dense populations, and its alarming deforestation rates, a remarkable knowledge gap exists on the ecology, the human and biophysical dimensions of this important ecosystem, particularly in comparison to other tropical forest biomes.
The Tropical Dry Forests network -TROPI-DRY- was created in 2005 under the CRN2 program to better understand TDF ecosystems using ecology, remote sensing, and human dimensions research. During the first phase of TROPI-DRY, emphasis was placed on the first standardized collection of information within Mexico, Costa Rica, Cuba, Venezuela, and Brazil regarding TDF extent, distribution, conservation and biodiversity status, phenological expressions and response to climate change. This process was complemented by an in-depth analysis of drivers of land use/cover change and conservation policies guided by social science findings, in the subsequent SGP-CRA 2021 project.
This next stage of the project is conducted on two main themes:
1) Modeling and forecasting to build on project data collection efforts over the last five years. By shaping that data into a comprehensive and accessible body of knowledge, they can more accurately assess the many functions played by primary and secondary tropical dry forests in the Americas, particularly as ecosystem services providers. This analysis will be conducted at different spatial scales: continental to country to regional level.
2) Outreach and stakeholder support by developing a clear, comprehensive synthesis of environmental degradation trends and the forces that drive these trends in tropical dry forests environments with emphasis on land use/cover change forces and climate change responses.
An inter-comparison of ecosystem services modeling approaches in the context of TDF environments will be used to:
(a) develop a policy based/decision-making synthesis based on knowledge exchange with policy makers, stakeholders and scientists working in TDFs; and
(b) provide an advanced decision making tool – based on modeling and forecasting – that includes information gleaned from policy-maker/stakeholder interaction. Addressing these issues from a multidisciplinary and multinational perspective can assist in building more sound conservation policies in TDF.
1 Modeled depletion of water tables in response to pasture establishment in 9 specific areas of the study basin
2 View of a tropical dry forest in the wet season
3 Same tropical dry forest in the dry season
Tropical dry forests (TDF), with their high agricultural and touristic potential and ideal conditions for human settlement are extremely vulnerable. This research network is developing a comprehensive knowledge basis of the human and biophysical dimensions for TDFs in the Americas. This project follows the research started in CRN 2021, with the same title.
Understand the role of tropical secondary forests play on interception of precipitation
at regional level
Quantify CO2 and H20 emissions from tropical dry forests to support programs for payments for environmental services based on accurate carbon and water models.
Develop innovative links between government agencies, scientists, and communities to promote sustainable management of TDFs.
We have been able to quantify carbon and water fluxes from tropical dry forests in Mexico and Costa Rica under different levels of environmental stresses.
Our research has been able to document significant linkages between remote sensing observations, micro-meteorology and vegetation stress for tropical dry forests not previously documented.
Our results in Mexico and Costa Rica suggest that regeneration of tropical dry forests increases rainfall interception by close to 80% after 5-years since colonization starts. The former has significant impact on regional water management in semi-arid and arid regions of the Americas.
In the context of climate change, tropical dry forests are demonstrating significant levels of resilience not previously documented.
Tropical dry forests in Mexico and Brazil are those with significant responses to climate change. These forests are demonstrating a significant decrease in productivity in the last 30-years.