Sustainable strategies for root-knot nematode control in agroecosystems

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Long-term sustainability of cork oak agro-forests in the Iberian Peninsula: A model-based approach aimed at supporting the best management options for the montado conservation

Publication . Arosa, Maria Luísa; Bastos, Rita; Cabral, João Alexandre; Freitas, Helena; Costa, Sofia R.; Santos, Mário

The future of the montado, a human shaped agro-forestry ecosystem of South Western Europe, is questioned due to the observed lack of cork oak health and low natural regeneration. We developed a System Dynamics Modelling approach to predict the long-term sustainability of this agro-forest, by recreating cork-oak population dynamics, management practices and the main environmental and biological constrains associated with this ecosystem. Our results indicate that the leading limitations to cork oak regeneration in montado ecosystems result from the intensity and interaction of land management practices, namely livestock and the use of heavy machinery. The main conclusions indicate that limiting the quantity of livestock up to 0.40 LU.ha -1 , and considering soil ploughing with a minimum periodicity of 5 years, are crucial to maintaining sustainable cork oak populations. This study represents a first step to support strategic options for cork oak montado management by providing projections of long-term population trends under realistic social-ecological change scenarios.

2017Journal article

Open access

Leaf decomposition of cork oak under three different land uses within a montado of southern Portugal

Publication . Arosa, Maria Luísa; Costa, Sofia R.; Freitas, Helena

This study compared litter decomposition dynamics of cork oak at three sites under different land-uses (grassland, shrubland and woodland), in a montado ecosystem in Southern Portugal. The montado is a protected habitat within the EU Habitats Directive, but the long-term persistence of cork oak is endangered in these ecosystems, with health of poor cork oak and low natural regeneration rates being the main causes of degradation. Moreover, human management has resulted in the conversion of woodlands to grasslands and may have long-term effects on soil nutrient availability, eventually modifying soil nutrient budgets. Knowledge of the ecological processes is therefore relevant for ecosystem management and species conservation. In the study, the estimated amount of leaf fall from cork oak showed no significant differences between land uses, despite the positive influence of tree crown size on leaf fall. Decomposition was affected by season, vegetation cover, leaf thickness and litter quality. Differences in land use that exposed soil to harsh climate conditions negatively affected soil microbial dynamics, resulting in lower decomposition rates in the more disturbed sites with lower canopy cover.

2017Journal article

Open access

Laimaphelenchus suberensis sp. nov. associated with Quercus suber in Portugal

Publication . Maleita, Carla Maria Nobre; Costa, Sofia R.; Abrantes, Isabel

Laimaphelenchus suberensis sp. nov. obtained from declining Quercus suber trees of Herdade da Gouveia de Baixo, Alentejo, Portugal, is described and illustrated based on morphological, biometrical and molecular characters. The diagnosis of Laimaphelenchus species has been commonly based on the presence or absence of a vulval flap and on the shape structure of the tail tip. The species described here has been included in the Laimaphelenchus group without vulval flap, and can be distinguished from morphologically similar species by its tail tip shape structure that has a stalk-like terminus and three diffuse tubercles with 4–6 finger-like protrusions. For the molecular analyses, the mitochondrial DNA region from the cytochrome oxidase subunit I (mtCOI), the D2-D3 expansion segments of the large subunit (LSU) and small subunit (SSU) of rRNA gene were amplified and sequenced. Sequences of L. suberensis sp. nov. clustered separately from all Laimaphelenchus spp. with available sequences in Genbank, confirming its identification as a new species. This is the second report of the genus Laimaphelenchus in Portugal, associated with Q. suber: L. heidelbergi and L. suberensis sp. nov.

2018Journal article

Open access