The seed bank in an old-growth, temperate deciduous forest

Abstract

Abstract:We assessed the size and composition of the seed bank in 31 plots representing a range of habitats within an old-growth, temperate deciduous forest at Mont St. Hilaire, Québec, Canada. We identified 49 taxa in the seed bank, with an average of 40 species·m -2 and a median density of 1218 seeds·m -2 . The most frequent seeds were species of Carex and Rubus, Diervilla lonicera, and Eupatorium rugosum, while seeds of Carex were the most numerous overall. Of the 12 species in the seed bank not found in the forest, 11 were found growing on the developed landscape surrounding this 10-km 2 forest fragment. These nonforest species were numerically only a minor component of the forest seed bank. Vernal herbs were not in the seed bank, and there were only a few tree species. Variation in seed bank richness among habitats was correlated positively with canopy cover, soil moisture, and soil nutrients, but not with the seed bank density or total number of species in the aboveground vegetation. Seed bank density increased with plot soil moisture. Woody species predominated in the seed bank of plots with richer soils, deeper litter, and more closed canopies. Herbaceous species predominated in the seed bank of plots with more open canopies, more mesic water regimes, and greater species richness in the aboveground vegetation. Contrary to earlier results suggesting forest seed banks primarily include shade-intolerant species associated with canopy disturbance or secondary succession, the seed bank in this old-growth, primary forest contains many shade-tolerant forest species.Key words: seed bank, old-growth forest, primary forest, temperate deciduous forest, habitat diversity, seed dispersal.Résumé : Les auteurs ont évalué la dimension et la composition de la banque de graines de 31 parcelles représentant une gamme d'habitats à l'intérieur d'une forêt décidue âgée située au Mont St-Hilaire, Québec, Canada. Ils ont identifié 49 taxons dans la banque de graines, avec une moyenne de 40 espèces·m -2 et une densité médiane de 1218 graines·m -2 . Les graines les plus fréquentes sont celles d'espèces de Carex et de Rubus, du Diervilla lonicera, et de l'Eupatorium rugosum, alors que les graines de Carex sont les plus nombreuses dans l'ensemble. Sur les 12 espèces de graines de la banque, absentes dans la forêt, on en retrouve 11 poussant sur les paysages développés qui entourrent ce fragment forestier de 10 km 2 . En nombres, ces espèces non-forestières ne constituent qu'une faible composante de la banque de graine de cette forêt. Les herbacées printanières ne se retrouvent pas dans la banque de graines et on n'observe que quelques espèces d'arbres. La variation de la richesse de la banque de graines varie selon les habitats et montre une corrélation positive avec l'ouverture de la canopée, l'humidité du sol et les nutriments du sol, mais non avec la densité des banques de graines ou le nombre total d'espèces dans la végétation épigée. La densité des banques de graines augmente avec l'humidité du sol des parcelles. Les espèces l...

Impact of Cardamom Cultivation on the Composition and Dynamics of Soil Seed Banks in a Conservation Forest in Sri Lanka: Implications for Conservation

“…The management adopted for cardamom cultivation increased the abundance of seeds of forbs, grasses, some light demanding tree and shrub species, and non-native species, and these effects persisted even 25 years after active management of the cardamom plantation had ceased. These results are consistent with other studies showing that frequent and/or intense disturbance to forests increases the density and alters the species composition of buried seeds (Leckie et al, 1999;Quintana-Ascencio et al, 1996;Sousa et al, 2017), although no other studies have demonstrated this phenomenon for forests disturbed by cultivation of understorey perennial crops such as cardamom or ginger.…”

“…Trees represented only 18% and 15% of all seeds in the soil of cardamom plantations and natural forests respectively. Undisturbed forests tend to have a higher proportion of tree seeds in the seed bank than disturbed forests (Garwood, 1989;Leckie et al, 1999). As in studies elsewhere (Kennedy & Swaine, 1992;Rico-Gray & Garcia-Franco, 1992), seeds of late-successional tree species were almost entirely absent from the soil seed banks of either CP or NF, which can be attributed to seed predation, their tendency to germinate quickly, and their lack of seed dormancy (Dupuy & Chazdon, 1998;Hall & Swaine, 1980;Hopkins & Graham, 1983;Leckie et al, 1999;Miller, 1999).…”

“…Undisturbed forests tend to have a higher proportion of tree seeds in the seed bank than disturbed forests (Garwood, 1989;Leckie et al, 1999). As in studies elsewhere (Kennedy & Swaine, 1992;Rico-Gray & Garcia-Franco, 1992), seeds of late-successional tree species were almost entirely absent from the soil seed banks of either CP or NF, which can be attributed to seed predation, their tendency to germinate quickly, and their lack of seed dormancy (Dupuy & Chazdon, 1998;Hall & Swaine, 1980;Hopkins & Graham, 1983;Leckie et al, 1999;Miller, 1999). In addition, many tropical tree species reproduce at irregular supra-annual intervals (Ashton et al, 1988;Connell & Green, 2000;Hart, 1995;Metz et al, 2008) and a lack of synchrony between fruit production of late-successional species and the time when the seed bank was sampled would lead to under-representation of these species in the sample.…”

“…Thus this assessment contributes baseline knowledge for designing approaches to the restoration and management of disturbed forests (Butler & Lemenih & Teketay, 2006;Martins & Engel, 2007;Richter & Stromberg, 2005;Wang et al, 2009). Several studies have documented a higher density of seeds, a higher proportion of early successional species and a greater species diversity in the seed banks of tropical forests disturbed by shifting cultivation or logging than in adjacent undisturbed forests (Alvarez-Aquino et al, 2005;Arevalo & Fernandez-Palacios, 2000;Dalling & Denslow, 1998;Leckie et al, 1999;Osumi & Sakurai, 1997;Quintana-Ascencio et al, 1996;Saulei & Swaine, 1988;Sousa et al 2017). To our knowledge no studies have investigated the effects of cultivating a perennial crop in the understorey of a tropical forest on the density and composition of soil seed banks and their implications for forest regeneration and the future structure of the tree community.…”

“…First, the reduction in stem density may increase canopy openness and thereby light transmission to the forest floor (Kumar et al, 1995;Parthasarathy, 1999). An increase in light availability may stimulate the development of an herbaceous ground flora including non-native species comprising both grasses and forbs (Garwood, 1989;Leckie et al, 1999).…”