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Biology subjects

Wadud, A. I.

Publications and source records attributed to Wadud, A. I..

2 recordsLinked to original sources

Resprouting sustains cork oak seedlings while recent grazing limits resprouting and survival

Regeneration failure is a bottleneck in Mediterranean oak woodlands. Cattle can hinder or promote recruitment, depending on grazing location, timing and intensity. Herbivory theory predicts that repeated defoliation and trampling deplete seedling reserves, whereas resprouting can extend survival; yet field studies rarely separate intensity from recency or combine long-run grazing records with individual fates and microhabitat/climate context. We test how management-driven heterogeneity shapes cork oak seedling survival and resprouting by combining 12 years of paddock-level grazing records with individual tracking of 8431 seedlings across 24 paddocks. Bayesian mixed-effects survival models related seedling lifespan to grazing history x pressure (moderate [≤]150; high >150 LSU ha-1 days yr-1) and to key covariates, including seedling height, resprouting status, shrub distance, cattle dung counts (as a proxy of very recent grazing), and 1-month SPEI (as recent water balance). Bayesianlogistic mixed models were then used to relate resprouting probability to grazing treatments. Survival was lower in grazed than ungrazed paddocks and declined along management gradients: median lifespan fell from 460 (moderate grazing) to 256 days (high), and from 460 (old grazing; two-year absence) to 199 days (recent). A two-year cattle absence increased survival under moderate pressure but was insufficient where pressure was high, indicating legacy effects and that recovery windows must scale with pressure. Resprouting dominated persistence: resprouters lived >5x longer than non-resprouters (2351 vs 460 days). Taller seedlings lived longer, and shrub proximity conferred a modest benefit. Climate modulated outcomes: wetter recent periods (higher SPEI) markedly boosted survival. Cattle reduced the odds of resprouting, with the strongest penalty under recent use. By disentangling grazing intensity from recency and linking both to seedling survival and resprouting, we show why recruitment falters under continuous, heavy grazing and when it can recover. Because drought intensifies cattle impacts, managers should combine moderate stocking rates with multi-year rest periods to rebuild oak bud banks and below-ground reserves; a two-year hiatus can help under moderate pressure but appears insufficient where pressure is high. Aligning rotational plans with drought outlooks and tracking simple field cues (seedling height, recent resprouting) offers a practical path to reconcile production with regeneration in Mediterranean wood-pastures. HighlightsO_LITwelve years of grazing records linked to 8431 cork oak seedling fates C_LIO_LIRecent grazing reduced survival and resprouting versus a two-year cattle absence C_LIO_LIHigh grazing shortened lifespan; two-year rest helped only under moderate pressure C_LIO_LIResprouting was the strongest survival correlate; resprouters lived over 5x longer C_LIO_LIWetter short-term water balance increased cork oak seedling longevity C_LI

ecology↗

Meta-analysis of livestock effects on tree regeneration in oak agroforestry systems

Livestock grazing occupies over a quarter of terrestrial land and is prevalent to agroforestry ecosystems, potentially affecting the survival, growth, and density of trees early developmental stages, such as seeds, seedlings, and saplings. To address the effects of livestock on tree recruitment in the face of ongoing debates about their impacts, we conducted a 33-year meta-analysis in Quercus-dominated agroforestry systems. Our analysis revealed a consistently negative effect of livestock on oak acorns, seedlings, and saplings. Significantly, livestock body size influenced oak regeneration, with small-sized livestock, notably sheep and goats, having a more pronounced negative impact compared to mixed-size systems, mainly involving cattle and sheep. The effects of small-sized livestock were markedly detrimental on acorn survival and seedling/sapling density, although no studies eligible for meta-analysis examined large livestock impacts on acorns. Overall, mixed-size livestock systems, often involving cattle and sheep, lessen the negative effects. Our findings indicate that the body size and foraging behaviors of livestock should be considered for the ecological sustainability of the tree component in agroforestry systems. While protective measures have long been integral to well-managed agroforestry systems, our results underscore the importance of integrating diverse livestock sizes and applying specific protective strategies, particularly for acorns and saplings, to further refine these practices. Future research should expand to underrepresented regions and livestock types to refine global agroforestry management practices. HighlightsO_LILivestock reduces oak tree regeneration at acorn, seedling, and sapling stages. C_LIO_LISmall livestock effect more negative, especially acorn survival and young oak density. C_LIO_LIMixed-size livestock agroforestry systems reduce harm more than small single-size ones. C_LIO_LIWe challenge perceptions that replacing cattle with sheep is necessarily less harmful. C_LIO_LIWe advocate for diverse livestock sizes in Quercus-dominated agroforestry systems. C_LI

ecology↗