Temporal Effects of Subsoil Compaction on Soil Strength and Plant Growth

Lowery, B.; Schuler, Ronald T.

doi:10.2136/sssaj1991.03615995005500010037x

Cited by 67 publications

(29 citation statements)

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“…The use of heavy machinery during restoration can be detrimental to soil properties and soil-regulated biotic processes (Lowery andSchuler 1991, Kozlowski 1999). Fangueo is a form of mechanical disturbance that at Palo Verde Marsh entails the use of a tractor.…”

Section: Discussionmentioning

confidence: 99%

Restoring diversity after cattail expansion: disturbance, resilience, and seasonality in a tropical dry wetland

Osland

González

Richardson

2011

Ecological Applications

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Abstract. As the human footprint expands, ecologists and resource managers are increasingly challenged to explain and manage abrupt ecosystem transformations (i.e., regime shifts). In this study, we investigated the role of a mechanical disturbance that has been used to restore and maintain local wetland diversity after a monotypic regime shift in northwestern Costa Rica [specifically, an abrupt landscape-scale cattail (Typha) expansion]. The study was conducted in Palo Verde Marsh (Palo Verde National Park; a RAMSAR Wetland of International Importance), a seasonally flooded freshwater wetland that has historically provided habitat for large populations of wading birds and waterfowl. A cattail (T. domingensis) expansion in the 1980s greatly altered the plant community and reduced avian habitat. Since then, Typha has been managed using a form of mechanical disturbance called fangueo (a Spanish word, pronounced ''fahn-gay-yo'' in English). We applied a Typha removal treatment at three levels (control, fangueo, and fangueo with fencing to exclude cattle grazing). Fangueo resulted in a large reduction in Typha dominance (i.e., decreased aboveground biomass, ramet density, and ramet height) and an increase in habitat heterogeneity. As in many ecosystems that have been defined by multiple and frequent disturbances, a large portion of the plant community regenerated after disturbance (via propagule banking) and fangueo resulted in a more diverse plant community that was strongly dictated by seasonal processes (i.e., distinct wet-and dry-season assemblages). Importantly, the mechanical disturbance had no apparent short-term impact on any of the soil properties we measured (including bulk density). Interestingly, low soil and foliar N:P values indicate that Palo Verde Marsh and other wetlands in the region may be nitrogen limited. Our results quantify how, in a cultural landscape where the historical disturbance regime has been altered and diversity has declined, a mechanical disturbance in combination with seasonal drought and flooding has been used to locally restrict a clonal monodominant plant expansion, create habitat heterogeneity, and maintain plant diversity.

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Section: Discussionmentioning

confidence: 99%

Restoring diversity after cattail expansion: disturbance, resilience, and seasonality in a tropical dry wetland

Osland

González

Richardson

2011

Ecological Applications

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“…The drained pore volume [24] and hydraulic conductivity under saturated conditions [22,11] are both seen to decrease while the penetration resistance increases [6,15]. Consolidation of a soil reduces its aeration, increases its mechanical strength and restricts the length and density of roots [1,25].…”

mentioning

confidence: 99%

Mechanical behaviour of silty clay loam/peat mixtures: cyclic compression-release tests and effects of initial water content

Vidal-Beaudet¹,

Charpentier²

1998

Agronomie

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-The mechanical properties of a silty clay loam (SCL), alone or amended with 20 or 40 % by volume of spaghnum peat, were studied at different values of water content. Cyclic uniaxial compression tests were applied using pressures of 30-500 kPa. The void ratios in the last 80 cycles are well represented by a simple function which assumes a limit value for an infinite number of cycles. The void ratio of moist or very moist silty clay loam compressed at 500 kPa is increased to about 55 and 115 % for 20 and 40 % peat contents, respectively. A comparison of the cyclic test with an oedometer (consolidometer) test yields similar results under unsaturated conditions. When the initial degree of saturation is greater than 0.5 and the initial void ratio is greater than 0.9, the compactibility is seen to increase for all the studied materials. A mixing model is used to study SCL and

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“…Although tractor use has the potential to alter soil and seed bank properties (Froud-Williams et al 1984;Lowery and Schuler 1991;Kozlowski 1999), a concurrent study found no short-term impact of fangueo on several soil and seed bank properties in Palo Verde Marsh (Osland et al 2011).…”

Section: Experimental Designmentioning

confidence: 96%

Coastal Freshwater Wetland Plant Community Response to Seasonal Drought and Flooding in Northwestern Costa Rica

2011

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Wetlands in tropical wet-dry climates are governed by distinct and extreme seasonal hydrologic fluctuations. In this study, we investigated the plant community response to seasonal flooding and drought in Palo Verde Marsh, Costa Rica. Climate change models for the region predict reduced rainfall and a drier wet season which would likely alter seasonal hydrologic cycles and prompt vegetation change. We quantified compositional change following disturbance emphasizing seasonal differences in plant life-form abundance across life history stages via standing vegetation, seed bank, and seedling recruitment measurements. Whereas the dry season standing vegetation was dominated by emergent species, aquatic species (floating-rooted, free-floating, and submerged life forms) were more dominant during the wet season. Seed bank and seedling recruitment measurements indicated that many species are resilient with life history traits that enable them to respond rapidly to extreme hydrologic filters. Interestingly, species richness was highest during seasonal flooding. Our results highlight the importance of early-wet season rainfall for plant regeneration and community change. Our findings also indicate that a drier future would likely have a large impact upon wetland plant communities with a decrease in species richness and an increase in the abundance of drought-tolerant emergent species.

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Temporal Effects of Subsoil Compaction on Soil Strength and Plant Growth

Cited by 67 publications

References 0 publications

Restoring diversity after cattail expansion: disturbance, resilience, and seasonality in a tropical dry wetland

Restoring diversity after cattail expansion: disturbance, resilience, and seasonality in a tropical dry wetland

Mechanical behaviour of silty clay loam/peat mixtures: cyclic compression-release tests and effects of initial water content

Coastal Freshwater Wetland Plant Community Response to Seasonal Drought and Flooding in Northwestern Costa Rica

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