Forests can help reduce the vulnerability of ecosystems and increase resilience. Thus, they contribute to climate change adaptation. On the other hand, forests can contribute to climate change mitigation if their role as carbon reservoirs and their potential to capture greenhouse gases are recognized. It is important to consider and distinguish this dual role forests play when conservation and sustainable management strategies are defined.
However, if an increase in global average temperature (2-4 °C) is expected in the future, this entails a risk to the existence of forests, and to their role and potential for adaptation and mitigation of climate change. Hence the importance of acting now to understand how the Andean forests contribute to reduce vulnerability, how they contribute to mitigate climate change, and how these elements integrate into climate change policies and the management of natural resources in the countries of the region.
The Andean Forests
©Jan R. Baiker
Andean Forests and Climate Change
However, in global efforts to tackle climate change, the issues of climate change adaptation and mitigation are still being discussed separately and with little linkage to the context of the Andean countries. This is reflected in the scattered investments and defining strategies promoted in countries with a greater orientation to lowland forests. However, from 2011, the consensus and demand from the Andean countries to seek mechanisms to explore and strengthen comprehensive strategies in the definition of policies at different levels (local, national and global), seeking synergies between adaptation and mitigation has grown. In this sense, sustainable management of resources, particularly in fragile ecosystems, is a key aspect to define this holistic view. This will require having a better understanding of the Andean forests, and their relation to climate change, to achieve greater recognition and prioritization of the work done in mountain forests in the international debate on climate change.
In addition to the impacts of climate change in the Andean countries, the processes of anthropic intervention have strongly influenced on the acceleration or slowing down of deforestation and degradation of the Andean forests.
Therefore, the importance and the difficulties of preserving native forests are highlighted globally. A balance between conservation and use may be found through sustainable forest management and ecosystem restoration so as to ensure the full range of forests contribution in the economic, social and environmental levels.
The Andean forests play a key role in the provision of ecosystem goods and services: they regulate the climate and water supply, mitigate floods and droughts, mitigate GHG emissions and maintain the habitats that allow a long-term permanence of biodiversity. However, they present important information gaps compared to other forest ecosystems (e.g. lowland forests). These gaps are due, in part, to the complexity of these ecosystems, and to different disturbances they present, both natural (e.g. landslides) and anthropogenic (e.g. deforestation and degradation) (Cuesta et al. 2012). Additionally, the interaction between climate change and the dynamics of change in land use cover and land use change (LULUCF) implies different impacts on the structure and functioning of these ecosystems and the welfare of the Andean people linked to the goods and services they provide (Peralvo et al.2012).
In this context, understanding the benefits derived from the forests and their role in local and national economy is essential, considering the growing need to develop comprehensive national strategies that acknowledge forests as strategic sectors of the economy, not only for the commercial use of their components, but also for their potential in mitigating climate change and the development of local adaptation actions. Thus, the role of Andean forests in adaptation and mitigation is highly relevant, so as to finally increase the resilience of populations and ecosystems, embedded in a context of promoting sustainable development.
Ecological Systems in the Andes and Biodiversity
The Andean region has a high diversity of ecosystems resulting from the interaction of biophysical processes at continental, sub-regional and local scales. Josse et al. (2009) identified 133 ecosystems in the North and Central Andes including woodlands and non-forested ecosystems under bioclimatic regimes ranging from xeric to rainforests. These diverse conditions go hand in hand with a patchwork of landscapes and land use regimes that modify and transform the Andean ecosystems under various social, economic, institutional and technological contexts. Andean forest ecosystems play key roles in these landscapes in processes that maintain biodiversity, capture and preserve carbon, regulate and ensure water supply among others.
Diversity patterns of Andean forests vary with elevation, as the main structuring gradient. The structure and composition of Andean forests in remote large tropical coastal mountains under the 1200-1500 m elevation is similar to the ecosystem of lowland forests. On that elevation, both diversity and canopy height decreases and communities of epiphytes and mosses increase in diversity and biomass (Scatena et al.2010). Diversity is also lower in the vicinity of the upper forest line, occurring monospecific patches in some cases.
The main attributes of biodiversity in the Andean forests are the high level of turnover in the altitudinal gradient and its importance in relation to richness and endemism considering the limited area they cover (Cuesta et al. 2009).
© Jan R. Baiker
Key Processes of the Andean Forest
The high diversity and endemism of the Andean forests is rooted in historical processes at different scales that occur in gradients of latitude, elevation and water seasonality (Kessler et al. 2011). The main processes that have generated this diversity include the complex orogeny of the range, the exchange of biota with North America through the Isthmus of Panama and the fragmentation of populations and subsequent recent radiation and speciation processes associated with Pleistocene climate changes (Weaver et al. 2012; Cuesta et al. 2009). Persistent knowledge gaps about basic ecology and biogeography of these forests highlight their importance for research and conservation of phylogenies, unique evolutionary processes, timber and non-timber forest products and genetic resources that may be crucial to species of cultivated plants (Abrahamczyk et al.2014; Young and Leon 1999).
Another important pattern in relation to the functionality of the Andean forests for climate change mitigation is the relative distribution of carbon content in air and soil biomass. In large elevation gradients covered by the Andean Forests, it is observed that air biomass (and the associated carbon content) decreases with elevation, with a significant contribution of organic carbon in soils (Girardin et al.2014; Spracklen and Righelato 2013). It has been found that the carbon stored in both compartments can vary between 130 and 200 Mg C ha-1 (Girardin et al.2010; Gibbon et al. 2010) although there is a high variability depending on meso-scale factors such as climate regime, slopes, soils and ecosystem types.
A key ecosystem process regarding the provision of benefits for people living in the vicinity of landscapes of Andean forests is the provision and regulation of water for different uses.
The hydrological significance of these ecosystems, especially in the case of cloud forests, comes from the interaction between horizontal rain, vegetation rich in epiphytes and the role it plays in the uptake and regulation of water within the hydrological cycle. This causes that the elevation at which the cooling of moist air masses from the lower regions occurs and the persistent formation of clouds be an important attribute both in the structure of cloud forests ecosystems (especially under seasonally dry and xerophytic regimes) and in the hydrology of watersheds contained in these forests (Bruijnzeel 2001). The provision and regulation services of these ecosystems are extended by a combination of low transpiration from vegetation, leaf litter and moss water storage and the high infiltration capacity of soils (Tobon 2009).
Forest Resources Use and Threats
Local livelihoods and their associated regimes of land use interact with the effects of climate change at local scales to generate significant impacts on the Andean forests. At the local and landscape level, the extractive uses of forest combined with the conversion of ecosystems to agricultural and livestock uses generate the most extensive short-term threats to the Andean forests. The underlying causes of these dynamics are associated with changes related to national and international market articulation, diversification of economic activities in rural areas, urban-rural connections and other common political, economic and institutional processes in the Andes and other developing regions (Ellis 2000). The current mosaics of land use and remnants of Andean forests are part of a process of land occupation and expansion of road infrastructure in place since pre-colonial times (Young and Leon 1999).
The impacts of climate change on the distribution, structure and function of ecosystems of Andean forests are added to the local and meso-scale effects of the coverage change dynamics.
It is recognized, at a global level, that the biota of mountain ecosystems, especially high mountain species in the Neotropics, is particularly sensitive to the effects of climate change. This pattern responds to restricted altitude and thermal ranges of distribution, high energy requirements and the potential contraction of distribution of these species due to temperature rise (Laurance et al.2011). Climate change may cause negative impacts on the Andean forests through changes in precipitation patterns, humidity, surface temperature, light availability, frequency of cloud cover, among other key bioclimatic variables. This causes changes in carbon fixation patterns of plants, mortality and regeneration rates of many species (Boehmer 2011).
Many of the impacts of climate change on the Andean forests are mediated by complex ecological processes and have been little studied.
Significant changes in the composition of communities of Andean forests, associated with changes in temperature in the last glaciation, have been documented (Cárdenas et al. 2011). An important factor is the ability of species to migrate on a par from their bioclimatic niches, which is related to processes of mutualism, competition, availability of key resources, among others. The type of species that constitute these new communities in the Andean forests will also be influenced by concomitant variations in ecotones (e.g. treeline) and how these can become selective barriers to the migration of certain species (Lutz et al.2013; Young and Leon 2007).
The linkages and feedback between the impacts of climate change and the changes in coverage and land use are complex.
The socio-environmental systems associated to Andean forest landscapes will suffer complex vulnerability and the adaptive capacity of both local livelihoods and species in forest ecosystems will result in heterogeneous impact patterns. For human populations, it is important to understand the patterns of access to key resources, the role of collective action options to facilitate (or hinder) adaptation and the influence of macro scale processes such as illegal crops in structuring decisions on land use (Cavelier and Etter 1993; Young and Lipton 2006). The persistence of natural species and communities (and the profits they generate) depend on their intrinsic characteristics and on the effectiveness of response of the Andean settlers (Young et al. 2010).
Key Problems
The problems identified below represent entry points into the mechanisms of threat and pressure affecting the Andean forests. It is not a prioritization exercise as the relative importance of these processes and their complexity depend on the scale and specificity of the processes of environmental governance, access and use of resources. In the same way, the problems discussed are interrelated, often amplifying the impacts on the Andean forests ecosystems, the populations of users and the managers of their resources.
Conversion and degradation of ecosystems
There are no robust regional statistics on deforestation processes, coverage change and land use, or degradation of Andean forest ecosystems. The reports from the Andean countries sometimes do not include specific analysis for Andean forests or use inconsistent definitions for these ecosystems at regional scale. However, there is evidence that in certain contexts of demographic, political and economic change, deforestation affects these ecosystems disproportionately compared to processes in lowland forests (Etter and van Wyngaarden 2000). The loss of altitudinal and horizontal connectivity in these ecosystems generates important impacts for restricted-range species, endemic species or specialist species (Young 1998).
Climate Change
Altering the geographical and temporal distribution of key bioclimatic variables represents significant threats to the persistence of biotic communities in the Andean forests. Knowledge of key ecosystem processes related to the capacity of Andean species to migrate and adapt to new conditions is scarce and fragmented. There is evidence that the interactions between climate change and cover change and land use affect certain species in different ways according to their ecological characteristics (Martin et al. 2011; Young and Leon 2007). These changes in the composition and structure of forest ecosystems have implications on their ability to provide ecosystem goods and services, especially those related to maintaining and capturing carbon and the provision and regulation of water (Tobon 2009).
Knowledge gaps about socio-environmental systems
In mountain environments in general, and particularly in the Andes, there are still knowledge gaps about the functioning of ecosystems, social systems and the processes that link them. The geographic and thematic scope of these knowledge gaps is varied, but some key issues can be identified on the necessity of promoting synergies between adaptation and mitigation to climate change in Andean forest landscapes:
Lack of long-term time-series observations of key processes related to hydrology, climate, biodiversity and land use at multiple scales.
Institutional dimensions of the livelihoods systems in Andean forests, especially in relation to collective action responses to threats associated with social and environmental processes.
Links between sustainable land management practices and the provision of key ecosystem goods and services.
Demand patterns of ecosystem goods and services and connection between stakeholders in territories, through externalities associated with land use regimes (e.g. agriculture – irrigation – agrochemical pollution).
Social and economic viability of sustainable productive alternatives, including low carbon agriculture and diversification of economic activities into other sectors.
Development of observation tools for social and environmental processes, appropriate for the heterogeneity of the Andean forest landscapes (Echavarria 1998).
Governance schemes not effective enough
A key element of any strategy for the sustainable management of landscapes and ecosystems of Andean forests is to have governance schemes that facilitate the articulation, communication and coordination of actors with different objectives, roles, interests and abilities. In this respect, little is still known about the factors that promote successful responses for the sustainable management of ecosystems and the benefits they generate, including but not limiting to perceptions of scarcity, characteristics of groups of users (e.g. heterogeneity, dependence on resources, internal conflicts), and resource characteristics (e.g. spatial distribution, economic value) (Ostrom 2009; Oldekop et al. 2012). In a context of decentralized environmental governance in the Andes, the needs to characterize and meet the challenges associated with the coordination between actors at different levels of governance (e.g. central and local governments) and actors at the same level of governance become even more critical.
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