Humans have heavily modified the natural systems of the Earth by introducing species that are non-endemic to the environment, leading to severe consequences. One species imported into the Spanish flora is the eucalyptus, a non-endemic species to the Iberian Peninsula, estimated to have arrived around the 1850s. Its speed of regeneration and its profitability in the timber production sector have established eucalyptus as the primary alternative for agriculture, becoming an essential resource for the Spanish industry. Although the eucalyptus occupies only 3% of the Spanish forest area, in Galicia, the concentration of the species predominates, accounting for 20% of the Galician soil.
Unlike the endemic oak, eucalyptus is highly flammable due to its high concentration of oils, which can be ignited at relatively low temperatures, making this species more prone to ignite quickly. Not only that, but the “thirsty” species need significantly more water than native oaks. Its extensive deep root systems allow them to access groundwater easily, causing the surface soil to be drier, and although Galicia is an area characterised by a lot of rain, water streams, and humidity, the dryness of soils in eucalyptus-dominated areas causes species with non-extensive root systems such as scrub grasses, nettles, and short plants to be more prone to burning in times of heat.
Today, the eucalyptus has become an integral part of the Galician ecosystem despite the long-term consequences. Its proliferation has not only been caused by humans but is also a natural characteristic of the species. Its capacity for expansion, though limited to close areas due to the type of seed, is cancelled out by its high capacity for regeneration, making it the ultimate survivor of wildfires. Instead of wiping out the species, wildfires create a feedback loop in which the high capacity for fast regeneration of eucalyptus allows it to surpass slow-growing endemic oaks, making it a species that Darwin would describe as the fittest for survival. This creates a homogeneous ecosystem where the dominant species is the water-junkie Australian species.
The proliferation of eucalyptus plantations across Galicia and their long-term repercussions on local communities and the environment, such as loss of biodiversity and an increase in wildfires, are examples of the challenges created by the Coupled Human-Natural System (CHANS). Fueled by the economic interactions between humans and the environment, this issue is widespread across the region. However, policies have shown little effort in addressing the environmental aspect since economic incentives remain a top priority.
Coupled Human and Natural Systems (CHANS)
Coupled Human and Natural Systems (CHANS) operate through feedback loops, affecting human relationships with different natural systems. The theory is a framework which explores the dynamic that interconnects humans with natural systems, interrelating them rather than separating them as if they were opposing entities. The introduction of eucalyptus as a non-endemic species can be analysed with the help of this framework, as its introduction by humans changed land use and local flora. The repercussions of this change have been seen in the last decades through wildfires and loss of biodiversity. This feedback loop has become unstoppable, and the policy response from the government has failed because decoupling economic activity from this resource would lead to serious financial consequences for the region. The struggle to strike the environmental and ecological balance has led to inadequate policymaking to address this issue.
Coupled human and natural systems can be conceptualized as entities with nested hierarchies (15, 29). In CHANS, people and nature interact reciprocally across diverse organizational levels. They form complex webs of interaction that are embedded in each other.
Liu, J., Dietz, T., Carpenter, S. R., Folke, C., Alberti, M., Redman, C. L., Schneider, S. H., Ostrom, E., Pell, A. N., Lubchenco, J., Taylor, W. W., Ouyang, Z., Deadman, P., Kratz, T., & Provencher, W. (2007). Coupled Human and Natural Systems
The market for pulpwood in the Iberian Peninsula, including Portugal, encouraged the proliferation of eucalyptus plantations across Galicia. Increased government support and subsidies to further develop this industrial area reinforced the economic dependency on this species as a natural resource. The characteristics of this species have made it attractive for rural landowners, as maintenance is low and the rate of return is both fast and high. The profitability of the species and its capacity for fast regeneration have increased eucalyptus’s coverage across the region. Despite the long-term environmental risks, convenience and economic motivations remain a priority for the private sector and rural landowners, who can profit from timber production and pulpwood, but at what cost?
The northern region of Portugal has the same problem with eucalyptus management, wildfires, and loss of biodiversity. Proportionally, Portugal is the country with the highest number of eucalyptus trees in the world, making it vulnerable to environmental disasters such as wildfires and loss of biodiversity due to the ecological consequences of for-profit monoculture tree plantations.
Dismantling unsustainable CHANS?
Dismantling the harmful effects of this CHANS requires more limitations on eucalyptus planting and addressing three key points. On the ecological aspect, a way to prevent wildfires from happening is by taking care of the forest and conserving it by mowing the grass to reduce fire risks. Instead of investing in wildfire-fighting technology, the Xunta de Galicia, alongside the local concellos, should work together to maintain forests in a less abandoned state. On the economic side, a transition to other natural resources is needed to rely less on eucalyptus and thus reduce their proliferation. Governments must subsidise other industries to help locals diversify their dependance on this species.
Lastly, this issue should be tackled through community participation and local programs using a bottom-up approach. By utilising Ostrom’s framework in dismantling unsustainable CHANS in Galicia through clearly defining boundaries of where this species is allowed, tailoring rules to local communities for their benefit, promoting collective governance through the participation of the concellos with civil society, and empowering locals through self-governance to take care of their resources and engage in decision-making processes.
Featured image provided by CNN Climate, 2024.