Linking environmental gradients, species composition, and vegetation indicators of sugar maple health in the northeastern United States

Abstract

Sugar maple (Acer saccharum Marsh.) decline has occurred throughout its range over the past 50 years, although decline symptoms are minimal where nutritional thresholds of Ca, Mg, and Mn are met. Here, we show that availability of these elements also controls vascular plant species composition in northern hardwood stands and we identify indicator species of these nutrient thresholds. Presence and abundance of vascular plant species and data on 35 environmental variables were collected from 86 stands in New Hampshire and Vermont (NHVT) and Pennsylvania and New York (PANY). Nonmetric multidimensional scaling ordination was used to determine which variables affected presence and abundance of species; both measures gave similar results. A base cation -acid cation nutrient gradient on axis one accounted for 71.9% (NHVT) and 63.0% (PANY) of the variation in the nonmetric multidimensional scaling ordination. Measures of Ca, Mg, and pH formed the base end and Al, Mn, K, soil acidity, and organic matter the acid end in both subregions. In both subregions, sugar maple foliar Mg and Ca had the strongest association with the base end of axis 1; exchangeable Al in NHVT and foliar Mn in PANY were strongly associated with the acid end. McNemar's exact test and indicator species analysis were used to determine which species were present in stands that met the nutritional thresholds for Ca, Mg, and Mn foliar chemistry. McNemar's exact test identified 16 species in NHVT and PANY, 16 additional species in NHVT only, and 12 additional species in PANY only. Indicator species analysis identified a subset of these species with the highest frequency of occurrence. Indicator species could provide land managers with a diagnostic tool for determining where on the landscape sugar maple is ''at risk'' or likely to remain healthy in the face of stresses.Résumé : Le dépérissement de l'érable à sucre (Acer saccharum Marshall) est survenu partout dans l'aire de répartition de cette essence au cours des 50 dernières années mais il y a très peu de symptômes de dépérissement aux endroits où les seuils nutritionnels pour Ca, Mg et Mn sont atteints. Nous montrons ici que la disponibilité de ces éléments régit égale-ment la composition en espèces de plantes vasculaires dans les peuplements de feuillus nordiques et nous identifions des espèces indicatrices des seuils pour ces nutriments. La présence et l'abondance des espèces de plantes vasculaires ainsi que 35 variables environnementales ont été mesurées dans 86 peuplements des É tats du New Hampshire et du Vermont (NHVT) ainsi que ceux de la Pennsylvanie et de New York (PANY). L'ordination de mesures multidimensionnelles non paramétriques a été utilisée pour déterminer quelles variables influencent la présence et l'abondance des espèces; les deux mesures ont produit des résultats similaires. Un gradient de nutriments allant des cations basiques à acides sur l'axe un expliquait 71,9% (NHVT) et 63% (PANY) de la variation dans l'ordination. Les mesures de Ca, Mg et de pH formaient la partie basique et A...

CO2 enrichment inhibits shoot nitrate assimilation in C3 but not C4 plants and slows growth under nitrate in C3 plants

“…experienced a population decline characterized by crown dieback and tree mortality throughout its range (Horsley et al 2008). This decline is usually attributed to acid rain and nutrient imbalances, although the supporting evidence is inconclusive (Minorsky 2003).…”

Sugar maple growth in relation to nutrition and stress in the northeastern United States

“…In NHVT, lithologic sources of glacial till soil parent material are diverse and have varying amounts of base cation supplies. To guide land managers in selecting sites to culture sugar maple, vegetation indicators have been developed to identify sites with adequate base cation nutrition for sugar maple in the absence of direct data on soil quality (Horsley et al 2008). While it is possible to maintain site productivity with soil amendments, operational procedures have not been developed and cost effectiveness is undetermined.…”

50 years ofscience-management cooperation

“…• Use indicator plants to help select sites with adequate Ca and Mg nutrition (see Horsley et al 2008).…”