Details

Autor(en) / Beteiligte

• Martin, Ella
• Hargreaves, Anna Lesley

Titel

Gradients in the time seeds take to germinate could alter global patterns in predation strength

Ist Teil von

• Journal of biogeography, 2023-05, Vol.50 (5), p.884-896

Ort / Verlag

Oxford: Wiley Subscription Services, Inc

Erscheinungsjahr

2023

Link zum Volltext

Quelle

Wiley Online Library

Beschreibungen/Notizen

• Aim Species interactions are predicted to become stronger toward low latitudes and elevations, and these predictions have been supported in large experiments measuring daily predation rates on early life‐stages. However, the overall strength and importance of predation depend on both the daily risk of being attacked and how long prey are exposed, and gradients in exposure time are rarely quantified. Here, we test whether time‐to‐germination, which determines seeds' exposure to post‐dispersal attack, is faster in high‐predation environments: low latitudes, low elevations, and warmer wetter climates. Location Global data synthesis. Taxon Angiosperms. Methods We synthesized data on time‐to‐germination from 1410 plant species spanning 118° latitude. We divided data by study environment (lab, greenhouse, garden, nature), as we predicted different patterns depending on whether seeds experienced only intrinsic versus intrinsic + extrinsic germination cues. We tested how mean days‐to‐germination varied with geography (latitude, elevation) and climate (annual mean and seasonality of temperature and precipitation). We also explored whether patterns could be explained by seed size or phylogeny, which vary latitudinally. Results Seeds germinated faster toward higher latitudes across study environments but slower toward higher elevations when experiencing intrinsic + extrinsic germination cues (in nature). Germination was faster in drier, more seasonal and—when tested in nature—warmer environments. Seed size explained some latitudinal variation in time‐to‐germination, whereas accounting for phylogeny did not improve predictions. Germination was slower in natural versus lab environments. Main Conclusions We found little evidence that seeds have commonly evolved faster germination in high‐predation environments. While time‐to‐germination varied with geography and climate, patterns were inconsistent among predictors, and were weaker than those reported for daily seed predation rates. Detected gradients in time‐to‐germination would partially counter elevational gradients in daily seed predation rates but exacerbate latitudinal gradients in predation rates, such that tropical seeds likely experience much stronger lifetime predation risk than high‐latitude seeds.