Biology subjects

Craveiro, J.

Publications and source records attributed to Craveiro, J..

4 recordsLinked to original sources

bioRxiv2026

Road proximity differentially shapes rodent-mediated seed dispersal frequency and distance

By concentrating rodents along verges, roads can reshape rodent-mediated seed dispersal, yet empirical tests remain scarce. We conducted a two-year field experiment in Mediterranean oak woodlands in southern Portugal to test how seed dispersal varies with distance from roads across road type (paved vs. unpaved) and road-forest context (edge vs. non-edge). We tracked labeled holm oak acorns, recording dispersal distances and the number of dispersal events. The two metrics responded differently to road distance. Dispersal distances changed little with distance from roads in non-edge contexts but increased in edge road-forest contexts (2x longer at 400 m than at 10 m) and showed a year x distance-to-road interaction, with longer dispersal distances farther from roads in the second year (a poor mast year). Dispersal distances were also longer when acorns were deposited under shrubs and in areas of higher tree density, and decreased with greater natural acorn availability. In contrast, the number of dispersal events declined with distance from roads (30% more events at 10 m than at 400 m) and was higher along unpaved than paved roads (39% more events). Dispersal frequency also increased in the poor mast year and with shrub cover. No acorns crossed the road. Thus, road verges can concentrate rodent seed handling but do not increase dispersal distances near roads nor provide cross-road seed connectivity; instead, dispersal outcomes depend on edge context, road type, and microhabitat structure. Management that retains structural cover at verges and the adjacent forest edge (e.g., shrub patches and non-uniform clearing) can harness verge-associated activity to increase acorn deposition in sheltered microsites and promote regeneration farther into forest interiors in roaded landscapes.

ecology↗

bioRxiv2025

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↗

bioRxiv2025

Carnivore-mediated seed crossings are more likely on roadkill hotspots

Roadkill hotspots concentrate animal movement and mortality, but whether they also interfere with animal-mediated seed dispersal--a conservation-relevant process underpinning plant regeneration and landscape connectivity--remains unknown. In Mediterranean oak woodlands of southern Portugal, we used seed mimics to test how road type (paved vs. unpaved) and road-forest context (edge vs. non-edge) shape carnivore-mediated seed crossings, and whether crossings coincide with roadkill hotspots detected by kernel density analysis. Bayesian logistic models indicated that seed-crossing probability was about twice as high on unpaved as on paved roads (predicted means 0.28 vs. 0.14), with weaker evidence for a negative edge effect. Crossing probability also tended to increase with carnivore abundance and distance to streams, and decrease with rodent density, albeit with some uncertainty. Crucially, paved sections intersecting roadkill hotspots showed nearly threefold higher predicted crossing probabilities than non-hotspot sections (0.51 vs. 0.18). These results yield clear conservation implications: prioritize paved segments that overlap carnivore roadkill hotspots. Implement precision measures--short-segment speed management, directional fencing that funnels animals to existing culverts/underpasses, and verge management that removes carcasses and limits small-mammal/scavenging attractants--to cut mortality while maintaining seed-mediated connectivity. A light, repeatable monitor-act-reassess workflow (hotspot mapping + seed-mimic trials + camera checks) enables rapid deployment and evaluation, and is transferable to other human-dominated forest mosaics. Hotspot-guided mitigation offers a pragmatic path to reconcile mobility infrastructure with living connectivity.

ecology↗

bioRxiv2025

Roads shape seed dispersal by rodents and carnivores at forest edges

The influence of road networks on seed dispersal remains poorly understood. We conducted a field experiment in Mediterranean oak woodlands of southern Portugal to assess how road type (paved vs. unpaved) and road-forest context (edge vs. non-edge) shape seed dispersal by rodents and carnivores. Using labeled acorns and seed mimics, we tracked dispersal distances, number of dispersals, road crossings, and dispersal directions. Rodents dispersed seeds farther in forest edges and along paved roadsides, predominantly moving them parallel to roads, but rarely across--although crossings were more frequent on unpaved roads. In contrast, carnivores mediated long-distance dispersal, primarily perpendicular to roads, and although seed road crossings were rare, carnivore-dispersed seeds crossed roads--especially unpaved ones--nine times more frequently than rodent-dispersed seeds. Shrub cover increased rodent-mediated dispersal events, heavier acorns traveled farther, and water patches decreased carnivore-mediated dispersal events near roads. These findings highlight the dual role of roads as barriers and of roadsides as corridors for seed dispersal, with implications for forest regeneration and landscape connectivity. Roadside management should prioritize moderate shrub cover along paved roads to support rodent dispersal while balancing ecological benefits with potential trade-offs. Unpaved roads, in turn, should be managed as functional corridors for carnivores, enhancing connectivity between fragmented forests. By integrating species-specific dispersal processes into road planning, landscapes can be designed to minimize road barrier effects while promoting natural regeneration in human-modified forests.

ecology↗