Percorrer por autor "Mosquera-Losada, Maria Rosa"
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- Grazing effects on soil compaction in mediterranean oak woodlandsPublication . Souza, Júlio Henrique Germano de; Mosquera-Losada, Maria Rosa; Castro, MarinaThis study evaluates the impact of grazing on soil compaction in two Mediterranean oak woodlands (Quercus rotundifoliaQ and Quercus pyrenaicaQp) in the Montesinho Natural Park in north-eastern Portugal. In each habitat, paired fenced plots (grazed versus ungrazed) were monitored. Soil samples were collected at depths of 0–10 cm and 10–30 cm in order to assess texture, bulk density, moisture content and penetration resistance. The Qr plot was grazed by goats at a moderate intensity for 15 consecutive days. Meanwhile, the Qp plot was grazed by sheep at a higher intensity for 55 intermittent days over an extended period. Soil resistance was measured using an impact penetrometer and analysed using two-way ANOVA—SS Type III, principal component analysis (PCA) and Pearson correlations. Grazing significantly increased soil compaction in the Qr plots (3.03 ± 0.23 vs. 1.87 ± 0.1 Mpa), but not in the Qp plots (2.03 ± 0.2 vs. 1.70 ± 0.1 Mpa). Penetration resistance was positively correlated with clay content and bulk density, and negatively with silt content and moisture content. This study, conducted in Mediterranean mountain forests with Q. pyrenaica established on Umbric Leptosols and Q. rotundifolia on stony Leptosols derived from basic rocks, demonstrates that the effects of grazing on soil compaction are more closely linked to the intrinsic properties of the soil than to grazing stocking rate itself. These findings demonstrate that pre-existing soil properties modulate the effects of grazing on soil compaction, underscoring the importance of site-specific conditions in the sustainable management of Mediterranean silvopastoral systems.
- The impact of goats grazing on understory vegetation of cork oak woodlandsPublication . Souza, Júlio Henrique Germano de; Mosquera-Losada, Maria Rosa; Castro, MarinaThe aim of this study is to evaluate the effects of high grazing pressure for short, intermittent periods (1-2 h per day) on fuel load management in cork oak (Quercus suber L.) forests in the north-eastern region of Portugal. This evaluation aims to understand the effectiveness of targeted grazing as a forest management tool, specifically in reducing fuel load accumulation and thereby potentially reducing wildfire risk. In addition, this study extends its analysis to examine the time required for vegetation recovery in the absence of grazing, with the aim of determining the optimal grazing interval. Changes in herbaceous and shrub cover, herbaceous biomass and phytovolume were compared between grazed and ungrazed plots over a period of thirty-four months. Using a stocking rate of 400 goats per hectare for 21 cumulative hours over 12 days resulted in a 93.43% reduction in shrub phytovolume and a 76.2% reduction in shrub cover. Herbaceous biomass also decreased from 53.80 +/- 7.82 g m-2 to 17.76 +/- 6.29 g m-2 in the grazed areas. Twenty-two months after cessation of grazing, no significant differences in plant and shrub cover or herbaceous biomass were observed. The results highlight the effectiveness of targeted grazing in managing fuel loads in cork oak woodlands, with pronounced short-term benefits. However, the rapid recovery of vegetation in the absence of grazing highlights the need for a strategic and continuous management approach to maintain the benefits of fuel reduction.