Introduction

The loss of biodiversity is a major environmental problem in nearly every terrestrial ecosystem on Earth. This loss is accelerating, driven by climate change, as well as by other causes including agricultural exploitation, fragmentation and degradation triggered by land-use changes. In particular, the impact of climate change on forest ecosystems and biodiversity is well documented in the literature and supported by the recent Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report (IPCC 2014), which states that irreversible modifications in the functioning and structure of forests are predicted to occur, especially in the Amazon and the Arctic. The expected changes in temperature and precipitation patterns will cause an increase in the intensity and frequency of extreme weather events, an expansion of subtropical desert regions, changes in agricultural yields and in the geographical distribution of disease vectors. All these factors will have profound impacts on the geographical distributions of natural communities, triggering modifications in plant and animal species, and increasing the risk of extinction. These impacts are of particular importance in Central America where, on the

one hand, a major share of the world’s biodiversity capital is concentrated and, on the other hand, ecological biodiversity loss strongly affects socio-economic vulnerability. Central America also represents an important biological corridor serving as a bridge between the North and South American ecosystems. Maintaining connectivity is therefore crucial for resident species of conservation concern that annually migrate in response to annual changes in the wet and dry seasons. The narrow, north-south orientation of the Central American landmass makes it particularly vulnerable to climate change. At its narrowest point, the isthmus is less than 130 km wide. Deforestation and loss of habitat in the isthmus can have consequences for biodiversity that are felt beyond the region. The current rate of the anthropogenic change, including the burning of greenhouse gases and agricultural expansion, is creating a doubly perilous situation threatening regional and global biodiversity. Protecting biodiversity and ecosystem services in the face of climate change must therefore be a key priority of this century. The potential consequences of biodiversity loss on the society have stimulated

considerable debate in recent years, as this is affecting ecosystem functioning and the goods and services provided to humans. As biodiversity decreases, we are losing

species and varieties of species, as well as goods and services to humans. The crucial issue under debate is the impact on the welfare of current and future population, and the role of humans in the exploitation of natural resources. Expected impacts of climate change on ecosystem services will therefore affect

human health both directly and indirectly. Services such as water supply, recreational activities, disease regulation and bioprospecting have a straightforward impact on human health, while others, such as soil retention and climate regulation, affect health through indirect pathways by providing a healthy environment and mitigation opportunities. Forest fires, as well as deforestation and fragmentation due to land-use change, will act as additional stressors to climate change by increasing the risk of degradation of tropical forests and causing a decline in many services. Degradation will result in deterioration of water quality, disruption of water supply, soil erosion, with increased risks of droughts or flooding, and infectious disease outbreaks. Water supply is among the forest services that will be highly affected by climate change, and freshwater ecosystem will see the highest amount of species at risk of extinction (Settele et al. 2014; MEA 2005). Central and South America show a high reliance on water supply which is critical for economic sectors such as agriculture and hydropower. Expected reduction of water flows and water quality would therefore have a high impact on the national economies as well. All these impacts will affect human welfare and can be translated in a cost for

the society through a variety of techniques known as market and non-market valuation, depending on the type of service addressed. Some services, such as recreational activities or aesthetic view are more difficult to value as they are not traded in the market and do not have therefore a price of reference, in comparison with other services such as hydropower and timber. All in all, the importance of economic valuation is incontestable for making appropriate decisions in the face of climate change and to set up suitable mitigation and adaptation strategies. Estimates of the cost of inaction, which is the expected impact without policy action, are also critical for policy-makers in the choice of future paths of development. In this context a number of studies exist in the literature addressing the bio-

physical impacts of climate change on tropical forests in Central America (Diaz and Morehouse 2003; Duncan 2011) or in other regions (e.g. Reich and Oleksyn 2008; Adams et al. 2009), while others are focusing more specifically on the expected economic costs for the society (Lawford, Alaback and Fuentes 1995; World Bank 2009; Gan, Grado and Munn 2010; Ding 2012). However, the coverage of available studies in the ecological and economic areas is still incomplete, and further research is required on both sides, as well as on their integration into a common framework suitable to link climatic and bio-physical processes with economic valuation and social welfare. Indeed, the role of climate change in this context is far from being understood, as well as the relationship between natural ecosystems, the provision of ecosystems services and their benefits to humans (TEEB 2010). Current research developments are also calling for studies that investigate on the economic values of ecosystem services under climate change.