Effects of variation in shade level, shade duration and light quality on perennial pastures

Dodd, Mike; McGowan, A. W.; Power, I.L.; Thorrold, B.S.

doi:10.1080/00288233.2005.9513686

Cited by 37 publications

(32 citation statements)

References 20 publications

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“…These trends are similar to the overall patterns found across all species in woodlands and that might reflect a general response of grassland species to light availability (Dodd et al . ). Although alien herbaceous species can in some cases reduce native tree species richness by limiting regeneration (Rogers ; Flory & Clay ; Thomsen et al .…”

Section: Discussionmentioning

confidence: 97%

Alien and native plant species play different roles in plant community structure

Bernard‐Verdier

Hulme

2014

Journal of Ecology

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Summary1. Although impacts of alien plants on species richness are widely reported, it remains unclear how common such effects might be and whether they differ from those due to native species. To date, too few studies have examined the impacts of a wide enough spectrum of native and alien species to address the importance of geographic origin on the richness of plant communities. 2. We investigated how total plant species richness, as well as its separate alien and native components, varied with the abundance of 115 alien and 146 native plant species across Banks Peninsula in New Zealand. Using null models, we tested whether significant correlations between the abundance of each focal species and species richness were more frequent than expected by chance. Examination of the differences in the relationships with species abundance found for native and alien richness can shed light as to whether alien species might be acting as drivers of biodiversity change or passengers responding to external environmental factors. 3. Significant relationships were rarely found for total richness due to contrasting trends of native and alien richness with species abundance. In contrast to natives, an increase in the abundance of an alien species revealed more frequent negative relationships with native richness and positive correlations with alien richness. 4. The relationship with species abundance found for native and alien components of richness differed between grasslands and woodlands. While we found putative support for negative impacts on native richness for several alien species in grasslands, the similar negative correlations in woodlands were more likely to reflect the shade intolerance of alien grasses where native species richness was high. 5. Synthesis. Our analyses reveal that widespread alien and native species play different roles in the plant communities in which they co-occur. Separately analysing the relationship with species abundance for alien and native components of richness can help distinguish between situations where aliens may be acting as the primary drivers in plant community changes or simply passengers. This is an essential first step in designing further experimental studies to determine the underlying ecological processes and potential ecosystem impacts of alien species.

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Section: Discussionmentioning

confidence: 97%

Alien and native plant species play different roles in plant community structure

Bernard‐Verdier

Hulme

2014

Journal of Ecology

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“…Pruning caused an increase in PPF (Table 2), maintained the R:FR and decreased soil temperature (Table 4). Light was limiting for pasture growth in the heavy shade throughout the growing season (Dodd et al 2005;Peri et al 2007), and the sward was observed to be less densely tillered (Table 6) due to the morphological responses of the pasture species to the low R:FR in the heavy shade. Additionally, sheep preferred grazing in light shade as opposed to heavy shade ( Table 9), suggesting that utilisation and grazing management of the pasture in heavy shade would be more difficult than in light shade (Peri et al 2001).…”

Section: Discussionmentioning

confidence: 99%

“…Understorey pasture production normally depends on the degree of competition between trees and pasture for light, moisture, and nutrients (Dodd et al 2005;Eastham and Rose 1988). Studies on Pinus radiata in New Zealand indicated that understorey herbage production decreases as crown density increases (Hawke and Knowles 1997;Pollock et al 1994).…”

Section: Introductionmentioning

confidence: 99%

Relationship between tree canopy height and the production of pasture species in a silvopastoral system based on alder trees

et al. 2008

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Silvopastoral systems in New Zealand that incorporate trees planted to control soil erosion on hills largely rely on the productivity of the pastoral system for financial returns. The effect on pasture productivity of increasing the tree canopy height by pruning Italian gray alder (Alnus cordata) was investigated by measuring the response of light, soil moisture, soil temperature, pasture production of major pasture species, and grazing behaviour of sheep. A split-plot design with four replicates was used. The main plot treatments were three levels of shade (81, 23, and 12% of available photosynthetic photon flux (PPF)), created by pruning 11 year old alder grown at the same density. The sub-plot treatments were four pasture mixes: perennial ryegrass (Lolium perenne), Yorkshire fog (Holcus lanatus), and cocksfoot (Dactylis glomerata), each sown with white clover (Trifolium repens), and cocksfoot sown with lotus (Lotus pedunculatus). Soil temperature was highest under light shade. Total herbage yield at 50 mm stubble height from October to May under heavy and medium shade was 60 and 80%, respectively, of the total herbage harvested under light shade. Cocksfoot had the greatest herbage yield, either with lotus or white clover. The tillering of perennial ryegrass was suppressed by shade more than for the other grass species making ryegrass unsuitable for use in this silvopastoral system. More sheep grazed in the light shade than in the heavy shade, but there was no difference in sheep preference for cocksfoot or Yorkshire fog. Lotus was grazed more frequently than white clover. Pruning of alder to increase canopy height has the potential to improve the productivity of the understorey pasture and its acceptability to sheep.

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“…Light intensity, soil moisture and nutrients are three major growth resources that determine productivity of silvopastoral and savanna ecosystems (Belsky 1994;Dodd et al 2005;Burner and MacKown 2006;Koukoura et al 2009). Trees in the systems create a horizontal structure above grasses (Sarmiento 1984;Tournebize and Sinoquet 1994) and modify availability of the growth resources (Vetaas 1992;Polley et al 1997;Benavides et al 2009) and thereby influence growths and yields of the grasses by facilitative or competitive mechanisms (Belsky 1994;Callaway and Walker 1997).…”

Section: Introductionmentioning

confidence: 99%

Forage production and nitrogen nutrition in three grasses under coconut tree shades in the humid-tropics

et al. 2011

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Reduction in forage production (FP) under trees in the humid tropics is well known, but information on how different levels of nitrogen (N) fertilizer influence FP under trees is meager. The present study reports effects of four N fertilizer levels (0, 60, 80 and 120 kg ha -1 N) on net soil N mineralization rate (NMR) and soil moisture (SM), FP, shoot biomass/root biomass ratio (SB/RB), N concentration in SB, N uptake and nitrogen use efficiency (NUE) of three grasses [guinea (Panicum maximum Jacq.), para (Brachiaria mutica (Forssk) Stapf) and hybrid-napier (Pennisetum purpureum Schumach.)] under three canopy positions [under canopy (UC, representing high shade), between canopy (BC, representing low shade) and open] of coconut trees (Cocos nucifera L.) in a coconut based silvopastoral system in the humid tropical climate of South Andaman Island of India. The study was performed for two annual cycles (2005-2006 and 2006-2007). The hypotheses tested were: (1) FP would decline under tree shades, both in N fertilized as well as no N fertilized conditions, when SM was not growth limiting in the open. However, amount of decline in the FP would depend on grass species and intensity of shades i.e., higher was the shade greater would be the decline; (2) N fertilizer would increase FP under tree shades, but the increase depended on grass species, intensity of shades and amount of N applied. Amount of N applied, however, would not annul the shades effects when SM was not growth limiting in the open. The study revealed that the tree reduced light 59% under UC and 32% under BC positions, but the N fertilizer levels increased NMR by 11-51% under UC and 3-44% under BC positions compared to the open. SM did not differ across the canopy positions. Under all situations, FP of all grasses declined under UC (47-78%) and BC (18-32%) positions compared to the open; the decline was greater in Hybrid-napier than Guinea and Para grasses. Forage production of all grasses increased with N fertilizer increments under all canopy positions reaching 32 t ha -1 dry matters for hybrid-napier at 120 kg ha -1 N in the open. Both guinea and para grasses outyielded hybrid-napier grass under UC but not under BC or in the open. N concentration in the forage (SB) also increased as N fertilizer level increased. These observations support our hypotheses and suggest that forage production under coconut palms can be increased by the application of N fertilizer with both guinea and para grasses being more productive than hybrid-napier grass under the high shade. Where light conditions are better, hybridnapier would produce more forage than the other species.

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Effects of variation in shade level, shade duration and light quality on perennial pastures

Cited by 37 publications

References 20 publications

Alien and native plant species play different roles in plant community structure

Alien and native plant species play different roles in plant community structure

Relationship between tree canopy height and the production of pasture species in a silvopastoral system based on alder trees

Forage production and nitrogen nutrition in three grasses under coconut tree shades in the humid-tropics

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