Previous land use alters plant allocation and growth in forest herbs

Abstract

Summary1 Former human practices can persistently influence forest ecosystems, particularly by altering the distribution and abundance of vegetation. Previous research has focused on the role of colonization success in governing plant community patterns in abandoned forests, but few studies have explored how changes in the performance of adult plants may contribute to changes in plant populations. 2 We examined patterns of biomass allocation and growth of 12 herbaceous plant species in southern Appalachian forest stands that have developed after agricultural abandonment or logging at least 55 years ago, to determine whether plant performance varied with land-use history. Soil nutrient availability and canopy closure were also investigated. 3 Adult plant biomass allocation varied appreciably among stands with different histories. Herbs in farmed stands generally allocated the most to leaves and the least to stems, while reference stands showed the opposite pattern. Plants in previously farmed sites had the highest rate of growth, although we observed considerable interspecific variation in plant performance. Stem allocation and relative growth rate were positively correlated in reference stands, but not in farmed or logged stands. Similarly, the growth of plants was clearly associated with soil nutrient concentration in reference stands but not in farmed or logged stands. 4 Differences in understorey density and soil nutrient availability may account for the observed patterns. Total herbaceous cover was appreciably lower in farmed and logged stands (58% and 51%) than in reference stands (78%), and soil phosphorus was higher in farmed stands than in logged and reference stands. Thus, competition for light and nutrients may be lower in farmed and logged stands than in reference stands, despite there being no difference in canopy closure with land-use history. 5 Overall, these results suggest that land-use history may influence environmental variables in ways that can enhance the performance of some herbaceous species. However, not all species may respond similarly to these changes.

History matters: Previous land use changes determine post-fire vegetation recovery in forested Mediterranean landscapes

“…Our results suggest that the longer the time since crop abandonment, the more heterogeneity in species and diversity of functional responses to potential perturbations are present, as previously reported (Rudel et al, 2005;Fraterrigo et al, 2006;Hermy and Verheyen, 2007), which thus increases the probability of rapid post-fire forest regeneration. Apart from the presence of nearby seed sources, the regeneration of a burnt area seems to depend either in the presence of fire-resistant soil and canopy seed banks or in the presence of species with resprouting ability (Rodrigo et al, 2004).…”

“…Land use changes and shifts in disturbance regimes (e.g. wildfires) are recognized worldwide as two of the major drivers of the current global change in terrestrial ecosystems (Vitousek, 1992;Rudel et al, 2005;Fraterrigo et al, 2006;Hermy and Verheyen, 2007). Surprisingly, the interaction between past land uses and fire impacts has received little attention.…”

“…carbon sequestration) of forest ecosystems (Rudel et al, 2005;Thompson et al, 2009;FAO et al, 2008). Land use changes are known to impact different ecological processes and influence soil properties (Fraterrigo et al, 2006;Hermy and Verheyen, 2007) leading to the general hypothesis that areas undergoing different land use trajectories are likely to differently respond to fire thus leading to differences in post-fire regeneration patterns (Duguy et al, 2007;Walck et al, 2011;Foster, 1992). Specific land use changes over time are likely to leave a strong signal on the capacity of the system to respond to fire.…”

Landscape Legacies

“…Assembly of herbaceous plant communities on disturbed lands likely occurs as a two-stage process in which restricted seed availability followed by a low recruitment limits colonization (Verheyen et al, 2003a;Baeten et al, 2009aBaeten et al, , 2009b). Several studies demonstrate that previous agriculture has neutral to positive effects on seed germination and adult plant performance (Donohue et al, 2000;Singleton et al, 2001;Endels et al, 2004;Verheyen and Hermy, 2004;Fraterrigo et al, 2006c;Flinn, 2007, but see Vellend, 2005), but negative effects on seedling and juvenile survival and growth, as well as juvenile and adult survival (Endels et al, 2004;Jacquemyn and Brys, 2008). For some species, a lack of microtopographic variation or microsite disturbance hampers establishment Flinn, 2007;Baeten et al, 2009b), whereas other species appear to be influenced by edaphic characteristics (Verheyen et al, 2003a).…”

Controls on Vegetation Structure in Southwestern Ponderosa Pine Forests, 1941 and 2004

“…A growing body of evidence demonstrates that landuse history can constrain subsequent vegetation development (Dupouey et al 2002, Foster et al 2003, Briggs et al 2006, Fraterrigo et al 2006. Historical livestock grazing practices may have had similar effects, particularly at very unsustainable intensities as occurred in the Southwest in the late 1800s (Haskett 1936, Abruzzi 1995, Fredrickson et al 1998.…”