Forest Research: Open Access
Open Access

The Vulnerability of Subtropical Mangrove Forests to Land Use and Land Cover Changes: Impacts and Mitigation Strategies

Nicolas J. Deere^{* *}Correspondence: Nicolas J. Deere, Department of Environmental Sciences, University of Cambridge, Cambridge, United Kingdom, Email:

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Description

Mangrove forests, which thrive in the intertidal zones of tropical and subtropical regions, are important ecosystems known for their high productivity and biodiversity. These unique forests provide essential services such as coastal protection, carbon sequestration, and nursery habitats for marine life. However, subtropical mangrove forests are increasingly vulnerable to changes in Land Use and Land Cover (LULC), which significantly impact their ecosystem production and overall health.

Ecological significance of subtropical mangroves

Subtropical mangroves, found along the coastlines of countries such as China, Japan, and parts of the United States, play a vital role in sustaining both terrestrial and marine environments. Their dense root systems stabilize shorelines, reducing erosion and mitigating the effects of storm surges. Mangroves also act as significant carbon sinks, sequestering carbon at rates much higher than many other forest types, which helps in combating climate change. Additionally, they provide critical habitats for a wide variety of species, supporting fisheries that are essential for local economies.

Impacts of land use and land cover changes

Land use and land cover changes, driven by human activities such as urbanization, agriculture, and aquaculture, pose a severe threat to mangrove ecosystems. These changes lead to habitat destruction, fragmentation, and alteration of hydrological regimes, all of which compromise the ecological integrity and productivity of mangrove forests.

Urbanization and coastal development: As coastal areas become increasingly urbanized, mangroves are often cleared to make way for infrastructure, housing, and tourism-related developments. This not only reduces the area of mangrove forests but also disrupts their connectivity, essential for maintaining genetic diversity and resilience. Urban runoff containing pollutants further degrades water quality, affecting mangrove health and productivity.

Agricultural expansion: Conversion of mangrove areas to agricultural land, particularly for rice paddies and oil palm plantations, leads to significant habitat loss. The alteration of land for agriculture often involves the construction of dykes and channels, which changes the natural water flow, salinity, and sediment deposition patterns critical for mangrove growth. The use of fertilizers and pesticides in adjacent agricultural fields can lead to nutrient loading and contamination of mangrove waters, resulting in eutrophication and declining ecosystem health.

Aquaculture practices: The rise of aquaculture, especially shrimp farming, has been one of the most significant drivers of mangrove loss. Large tracts of mangrove forests are cleared to create ponds for shrimp cultivation, disrupting the natural ecosystem and its services. The practice often involves the use of chemicals and antibiotics, which can seep into surrounding mangrove areas, causing pollution and further degrading these ecosystems.

Consequences on ecosystem production

The degradation and loss of subtropical mangroves due to LULC changes have extreme implications for ecosystem production. These impacts can be seen in various dimensions:

Reduced biodiversity: Mangroves support diverse biological communities. Habitat loss and fragmentation lead to a decline in species diversity and abundance, which in turn affects ecosystem functions such as nutrient cycling, primary production, and resilience to environmental changes.

Altered carbon sequestration: Mangroves are highly efficient at sequestering carbon, both in their biomass and in the soil. The destruction of these forests not only releases stored carbon, contributing to greenhouse gas emissions, but also diminishes the capacity for future carbon sequestration, exacerbating global climate change.

Decline in fisheries productivity: Many commercially important fish and shellfish species depend on mangrove habitats during their juvenile stages. The degradation of mangroves leads to a decline in these populations, adversely affecting local fisheries and the livelihoods dependent on them.

Hydrological changes: Alterations in the natural hydrological regime due to LULC changes can affect the salinity and nutrient levels in mangrove forests, impacting their growth and productivity. For instance, reduced freshwater inflows can increase salinity beyond the tolerance levels of certain mangrove species, leading to their decline.

Strategies for mitigation and conservation

To mitigate the impacts of LULC changes on subtropical mangrove forests, a multifaceted approach is required:

Protective legislation: Enforcing stringent laws to protect existing mangrove forests from deforestation and degradation is crucial. Legal frameworks should also promote sustainable land use practices that consider the ecological importance of mangroves.

Restoration projects: Active restoration of degraded mangrove areas can help recover lost functions and services. This includes replanting native species and restoring natural hydrological patterns.

Community engagement: Involving local communities in conservation efforts ensures the sustainability of these initiatives. Providing education and alternative livelihoods can
reduce the pressure on mangrove forests from activities like illegal logging and unsustainable fishing.

Integrated Coastal Zone Management (ICZM): Adopting ICZM practices that balance ecological, economic, and social objectives can help manage coastal areas sustainably. This approach involves stakeholder participation, scientific research, and policy integration to address the multifaceted challenges facing mangrove ecosystems. Subtropical mangrove forests are invaluable yet vulnerable ecosystems. Addressing the adverse effects of land use and land cover changes requires concerted efforts from policymakers, scientists, and local communities to ensure the preservation and resilience of these critical natural assets.