Definition of Soil Biodiversity
European Convention on Biological Diversity (CBD) defined the soil biodiversity as “the variation in soil life, from genes to communities, and the ecological complexes of which they are part, that is from soil micro-habitats to landscapes”.
In other words, the soil biodiversity represents the variety of life belowground. The term biodiversity denotes the number of distinct species (richness) and their proportional abundance (evenness) present in a system, but may be extended to encompass phenotypic (expressed), functional, structural or trophic diversity. The total biomass belowground generally equals or exceeds that aboveground. At the same time, especially in regards with the microbial scale, the biodiversity in the soil always exceeds that on the associated surface by orders of magnitude.
Biodiversity underpins sustainable development and is central food production, the provision of clean water and achieving environmental goals. There is growing concern about the unprecedented rate of global biodiversity loss. Direct drivers of biodiversity loss include pollution and nutrient overload, overexploitation of resources, land fragmentation and soil erosion, climate change and biological invasions. Socio-cultural factors, such as lifestyle and consumer choices, can be indirect drivers of biodiversity loss and the disruption of ecosystems.
Biodiversity decline (within all soil horizons)
Decline in soil biodiversity is the reduction of forms of life living in soils, both in terms of quantity and variety. Soil biodiversity is under increasing pressure because of threats to soil, such as erosion, contamination, salinization and sealing. These events threaten soil biodiversity by compromising or destroying the habitat of the soil biota.
Management practices that reduce the deposition or persistence of organic matter in soils, or bypass biologically-mediated nutrient cycling also tend to reduce the size and complexity of soil communities. It is however notable that even polluted or severely disturbed soils still support relatively high levels of microbial diversity at least. It has been observed that specific groups may be more susceptible to certain pollutants or stresses than others (e.g., nitrogen-fixing bacteria that are symbiotic to legumes are particularly sensitive to copper). Additional studies on the negative effects of direct and indirect soil threats on specific organisms are required.
Malta and soil biodiversity
In order to tackle the aforementioned issues Malta’s National Biodiversity Strategy and Action Plan (NBSAP) has already been adopted and applied.
Through the NBSAP, national targets have been set to be reached by 2020 in support of Malta’s natural heritage. Some of the targets address both direct pressures and underlying causes of biodiversity loss. A number of other targets are aimed at improving the status of Malta’s biodiversity and enhancing the benefits from biodiversity and associated life supporting services. The finalisation of the NBSAP fulfils one of the requirements for the National Environment Policy by providing the comprehensive strategic framework to protect Malta’s biodiversity. The conservation and sustainable use of biodiversity has a positive impact on the standard of living and on sectors such as tourism that are central for generating commercial activity and employment. On the other hand, such sectors must continue to develop in a sustainable manner and in ways that respect biodiversity and enrich our environment. It is therefore important that biodiversity is integrated in the relevant policies that directly or indirectly affect biodiversity.
Protecting Malta’s biodiversity presents a big challenge. Malta has a very small land mass, coupled with the highest population density in Europe. As a small island state, Malta faces the challenge of meeting the future demands of a growing population for land, water, food and energy, while at the same time halting the loss of biodiversity and the degradation of ecosystem services. This challenge is exacerbated by other environmental concerns, which are inherent to our isolated and insular ecosystems. The status of Malta’s biodiversity is still not understood well enough. The status of 36% of Maltese species and 29% of Maltese habitats listed in the EC Habitats Directive is still unknown; a significant number of these relate to the marine environment. These knowledge gaps hinder the development and implementation of effective protection and conservation. In addition, 44% of species and 64% of habitats do not have a favourable conservation status and hence require enhanced conservation action.
Several goals are set regarding biodiversity and soil, especially through sustainable use of the natural resources, Soil, Water and Land:
- High Nature Value Farmland (HNVF) in Malta is mapped according to defined criteria, and good agricultural and low-intensive practices, including organic farming, are applied to preserve such land and associated agrobiodiversity.
- Land uses are commensurate with the management of soil and by inference, water resources across the Maltese Islands. This is required in order to promote: the build-up of soil organic matter; the enhancement of soil biodiversity; the reduction (and reversal, where possible) of soil erosion, contamination and compaction; the minimisation of salinization/sodification levels (where applicable); the mitigation of flood-induced soil mass displacement/ land sliding; and the increase in infiltration and moisture retention in the soil. Measures incorporated in a soil action plan are formulated to address these goals in terms of how to mitigate the threats to Maltese soils and adopt measures aimed at soil conservation. The soil action plan and other national relevant policies shall contribute towards the requirements of the Convention to Combat Desertification (UNCCD) to develop desertification national action programmes.
- Transposition and implementation of the Pesticides Framework Directive, which advocates the sustainable use of pesticides and integrated pest management, assists in reducing the potential damage on biological and water resources caused by pesticides. This is supported by the development of a national action plan
- Effective measures are in place and implemented to address the over-abstraction and pollution of groundwaters, namely by nitrates and chlorides, in line with the Groundwater Directive, the Nitrates Directive, the Dangerous Substances Directive, transposing national legislation, the National Water Policy for the Future, and the Water Catchment Management Plan for Malta.
- Appropriate and cost-effective rainwater harvest technologies are adopted, where feasible, in urban and rural areas as an environmentally sound approach to address imbalances between water supply and demand, and thus ensure long term water security in Malta (links with NR4).
- Integrated water resources management, based on the ecosystem approach, is achieved via the full implementation of the Water Framework Directive and its programme of measures as well as the Marine Strategy Framework Directive. Such implementation shall be in a mutually supporting manner in the case of coastal waters. The successful implementation of measures in the Water Catchment Management Plan for Malta results in the attainment of “Good Ecological Status” in surface waters, “Good Chemical Status” for groundwater and surface waters, and “Good Quantitative Status” for groundwater bodies, all by 2015 (and if this is not possible, by 2021 or 2027). “Good Environmental Status” in the marine environment is achieved by 2020, at the latest, via drawing up a national marine strategy by 2016, and, where possible supported by other policies in line with relevant Regional Seas Conventions. Implementation of the MSFD on a national level also contributes to the goals of the EU’s Integrated Maritime Policy.