Competitive effects of shrubs and grasses in prairie

Köchy, Martin; Wilson, Scott D.

doi:10.1034/j.1600-0706.2000.910219.x

Cited by 88 publications

(82 citation statements)

References 66 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In our experiment, the presence of grass vegetation in the vicinity of Scots pine seedlings greatly reduced light availability (transmitted PAR=20%) in the lower part of the pine (Fig. 3), as also reported by Ko¨chy and Wilson (2000) and Peltzer and Ko¨chy (2001). However, the upper part of pine seedlings received more than 70% of incident PAR.…”

Section: Discussionsupporting

confidence: 68%

The role of below-ground competition during early stages of secondary succession: the case of 3-year-old Scots pine (Pinus sylvestris L.) seedlings in an abandoned grassland

Picon‐Cochard

Coll

Balandier³

2006

Oecologia

View full text Add to dashboard Cite

In abandoned or extensively managed grasslands, the mechanisms involved in pioneer tree species success are not fully explained. Resource competition among plants and microclimate modifications have been emphasised as possible mechanisms to explain variation of survivorship and growth. In this study, we evaluated a number of mechanisms that may lead to successful survival and growth of seedlings of a pioneer tree species (Pinus sylvestris) in a grass-dominated grassland. Three-year-old Scots pines were planted in an extensively managed grassland of the French Massif Central and for 2 years were either maintained in bare soil or subjected to aerial and below-ground interactions induced by grass vegetation. Soil temperatures were slightly higher in bare soil than under the grass vegetation, but not to an extent explaining pine growth differences. The tall grass canopy reduced light transmission by 77% at ground level and by 20% in the upper part of Scots pine seedlings. Grass vegetation presence also significantly decreased soil volumetric water content (Hv) and soil nitrate in spring and in summer. In these conditions, the average tree height was reduced by 5% compared to trees grown in bare soil, and plant biomass was reduced by 85%. Scots pine intrinsic water-use efficiency (A/g), measured by leaf gas-exchange, increased when Hv decreased owing to a rapid decline of stomatal conductance (g). This result was also confirmed by delta 13C analyses of needles. A summer 15N labelling of seedlings and grass vegetation confirmed the higher NO3 capture capacity of grass vegetation in comparison with Scots pine seedlings. Our results provide evidence that the seedlings' success was linked to tolerance of below-ground resource depletion (particularly water) induced by grass vegetation based on morphological and physiological plasticity as well as to resource conservation.

show abstract

Section: Discussionsupporting

confidence: 68%

The role of below-ground competition during early stages of secondary succession: the case of 3-year-old Scots pine (Pinus sylvestris L.) seedlings in an abandoned grassland

Picon‐Cochard

Coll

Balandier³

2006

Oecologia

View full text Add to dashboard Cite

show abstract

“…We consider it unlikely that seed dispersal limitation would be an important factor here, since seedproducing shrubs grow in close proximity to all HMGs. It is well documented that competition from dense grass swards prevents woody seedling establishment in grasslands in general (Kö chy and Wilson 2000), and also specifically in alpine grasslands (Welling and Laine 2002;Olofsson and Shams 2007;Klanderud 2010;Milbau and others 2013). Dense grass swards, aided by a high mineral N availability in the HMGs, probably efficiently prevent shrubs from establishing from seeds.…”

Section: Discussionmentioning

confidence: 99%

Multiple Feedbacks Contribute to a Centennial Legacy of Reindeer on Tundra Vegetation

et al. 2018

View full text Add to dashboard Cite

Historical contingency is the impact of past events, like the timing and order of species arrival, on community assembly, and can sometimes result in alternative stable states of ecological communities. Large herbivores, wild and domestic, can cause profound changes in the structure and functioning of plant communities and therefore probably influence historical contingency; however, little empirical data on the stability of such shifts or subsequent drivers of stability are available. We studied the centennial legacy of reindeer (Rangifer tarandus) pressure on arctic tundra vegetation by considering historical milking grounds (HMGs): graminoid-and forb-dominated patches amid shrub-dominated tundra, formed by historical Sami reindeer herding practices that ended approximately 100 years ago. Our results show that the core areas of all studied HMGs remained strikingly stable, being hardly invaded by surrounding shrubs. Soil nitrogen concentrations were comparable to heavily grazed areas. However, the HMGs are slowly being reinvaded by vegetative growth of shrubs at the edges, and the rate of ingrowth increased with higher mineral N availability. Furthermore, our data indicate that several biotic feedbacks contribute to the stability of the HMGs: increased nutrient turnover supporting herbaceous vegetation, strong interspecific competition preventing invasion and herbivore damage to invading shrubs. In particular, voles and lemmings appear to be important, selectively damaging shrubs in the HMGs. We concluded that HMGs provide clear evidence for historical contingency of herbivore effects in arctic ecosystems. We showed that several biotic feedbacks can contribute to subsequent vegetation stability, but their relative importance will vary in time and space.

show abstract

“…By contrast, comparing areas of forest (blue rectangle) and cerrado (gray rectangle) with similar rainfall regimes (34 mm), the forest region remains considerably wetter (∼ 15 % in both shallow and deeper layers). According to Köchy and Wilson (2000), high rates of water uptake per unit mass may reflect the high root density of the vegetation. In fact, James et al (2003) found at a site 20 km east of Regina, Canada The period chosen for this study coincided with the peak of the biomass burning season when a total of 439 297 fires were detected in the area of the model domain by AVHRR-NOAA, which is 42 % of the total number of fires detected by the same sensor during the entire burning season.…”

Section: Soil Moisture and Fire Activitymentioning

confidence: 99%

Modeling the radiative effects of biomass burning aerosols on carbon fluxes in the Amazon region

et al. 2017

View full text Add to dashboard Cite

Abstract. Every year, a dense smoke haze covers a large portion of South America originating from fires in the Amazon Basin and central parts of Brazil during the dry biomass burning season between August and October. Over a large portion of South America, the average aerosol optical depth at 550 nm exceeds 1.0 during the fire season, while the background value during the rainy season is below 0.2. Biomass burning aerosol particles increase scattering and absorption of the incident solar radiation. The regional-scale aerosol layer reduces the amount of solar energy reaching the surface, cools the near-surface air, and increases the diffuse radiation fraction over a large disturbed area of the Amazon rainforest. These factors affect the energy and CO 2 fluxes at the surface. In this work, we applied a fully integrated atmospheric model to assess the impact of biomass burning aerosols in CO 2 fluxes in the Amazon region during 2010. We address the effects of the attenuation of global solar radiation and the enhancement of the diffuse solar radiation flux inside the vegetation canopy. Our results indicate that biomass burning aerosols led to increases of about 27 % in the gross primary productivity of Amazonia and 10 % in plant respiration as well as a decline in soil respiration of 3 %. Consequently, in our model Amazonia became a net carbon sink; net ecosystem exchange during September 2010 dropped from +101 to −104 TgC when the aerosol effects are considered, mainly due to the aerosol diffuse radiation effect. For the forest biome, our results point to a dominance of the diffuse radiation effect on CO 2 fluxes, reaching a balancePublished by Copernicus Publications on behalf of the European Geosciences Union. 14786 D. S. Moreira et al.: Modeling the radiative effects of biomass burning aerosols of 50-50 % between the diffuse and direct aerosol effects for high aerosol loads. For C3 grasses and savanna (cerrado), as expected, the contribution of the diffuse radiation effect is much lower, tending to zero with the increase in aerosol load. Taking all biomes together, our model shows the Amazon during the dry season, in the presence of high biomass burning aerosol loads, changing from being a source to being a sink of CO 2 to the atmosphere.

show abstract

Competitive effects of shrubs and grasses in prairie

Cited by 88 publications

References 66 publications

The role of below-ground competition during early stages of secondary succession: the case of 3-year-old Scots pine (Pinus sylvestris L.) seedlings in an abandoned grassland

The role of below-ground competition during early stages of secondary succession: the case of 3-year-old Scots pine (Pinus sylvestris L.) seedlings in an abandoned grassland

Multiple Feedbacks Contribute to a Centennial Legacy of Reindeer on Tundra Vegetation

Modeling the radiative effects of biomass burning aerosols on carbon fluxes in the Amazon region

Contact Info

Product

Resources

About