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Study Of The Diversity Of Soil Animal Community In The Songnen Plain Grassland Of China, Yin Xiuqin, Zhu Tingcheng, Zhong Weiyan, Peng Wu Kui

IGC Proceedings (1997-2023)

This paper makes a diversity study of 8 habitats of soil animal communities in Songnen plain grassland. The research shows that the better the habitat condition is, the higher the diversity index of soil animals, and the worse the habitat condition is the lower the diversity index of soil animals. The diversity of soil animal communities has a positive relationship with soil organic matter, total nitrogen, and has a negative relationship with pH value. It has no obvious relationship with soil water content and total phosphorus. The diversity of soil animal communities decreases with increasing depth of soil layer and …

Clipping Intensity Impacts On Root Mass Variation Of Cool Season Grasses, D L. Stetson, W M. Sullivan

IGC Proceedings (1997-2023)

Seasonal changes in grass root and mat weight density were documented under different cutting managements. Kentucky bluegrass (Poa pratensis L.) and tall fescue (Festuca arundinacea Schreb.) received one annual cut, twice yearly forage harvest, and mown turf treatments. Orchardgrass (Dactylis glomerata L.) received one annual and twice yearly cutting treatments. Soil cores were collected to a 15 cm depth and divided into 7.5 cm increments. Roots and mat were recovered, washed, dried and weighed. Differences in years, seasons, species, treatments, and soil depth significantly influenced total root weight density and fine root density. With all species and …

Effects Of Nitrogen On The Growth Of Hyparrhenia Diplandra, J Nkandza

IGC Proceedings (1997-2023)

The nitrogen effects on Hyparrhenia diplandra were studied. Plants were grown on nutrient solutions of variable concentrations in nitrogen. The supplied nitrogen increased tillering, leaf production, lamina area, total dry matter accumulation and total nitrogen accumulation in lamina. A detailed examination showed that the effect on tillering was the main cause of the differences observed in dry weights between different treatments. The nitrogen supply elongated significantly the lamina and nitrogen deficiency increased its thickness; but this was not enough to compensate the loss of weight in lower nitrogen treatment. The lamina area as well as nitrogen accumulation in the lamina …

Movement Of Allelopathic Compound Coumarin From Plant Residue Of Sweet Vernalgrass (Anthoxanthum Odoratum L.) To Soil, Yoshito Yamamoto

IGC Proceedings (1997-2023)

This study investigated the movement of coumarin, an allelopathic compound, from the plant residue of sweet vernalgrass (Anthoxanthum odoratum L.) to soil, as well as the dynamics of coumarin in soil. The level of coumarin dissolved from sweet vernalgrass plant residue in both Andosols and Cambisols, which were watered every day, peaked on the 5th day after the beginning of watering, and fell gradually with each additional of day. Specifically, the coumarin content in Cambisols on the 5th day was 14.2 ppm, which is 4 times the coumarin level found in Andosols. The recovery percentage of coumarin extracted with …

Evaluating Functional Diversity As Potential Early-Warning Indicator Of Rangeland Degradation, L.-M. Schwarz, C. P. Carmona, M. C. Bilton, F. Munyebvu-Chambara, K. Behn, A. Linstädter

IGC Proceedings (1997-2023)

Droughts and overgrazing play a crucial role in the degradation of semi-arid rangelands. This is evident in the loss of palatable long-lived grass species and bush encroachment. Early warning indicators are needed to mitigate long-term degradation and decline in essential forage provision. Functional diversity provides valuable information on ecosystem health. However, functional diversity indices have not yet been tested regarding their applicability as early warning indicators, revealing non-linear threshold behaviour. We therefore examined the following questions: (1) How do functional diversity indices respond to grazing pressure? (2) Does land tenure affect the relationship between functional diversity and grazing pressure? (3) …

Variation Of Ldmc And Sla Relationship Between Growth Forms In Natural Grasslands, J. Viégas, P. Cruz, J. P. Theau, C. Jouany, P. Ansquer, R. Al Haj Khaled, O. Therond, M. Duru

IGC Proceedings (1997-2023)

In agro-ecological studies, there is a growing interest in measuring both leaf dry matter content (LDMC) and specific leaf area (SLA). This interest lies on the fact that leaf traits are linked to gradients of environmental factors and ecosystem functions. Working with three contrasting wild species, Garnier et al. (2001) proposed a model linking these two traits. The model shows a relatively simple non linear and negative correlation between LDMC and SLA. Nevertheless, none of the species used to build the model were grasses (GRA) or forb rosettes (ROS = i.e. dicotyledonous with large entire leaves and absence of …

A Study In Cuba Of The Biology, Ecology And Agroecological Management Of Heteropsylla Cubana Crawford In Leucaena Leucocephala (Lam.) De Wit, N. Valenciaga, M. Felicia Díaz, T. E. Ruíz, M. Fernández, C. Mora

IGC Proceedings (1997-2023)

As a consequence of the increase in Leucaena leucocephala areas to counter the shortage of feed in Cuban cattle production, there is a risk of the development of Heteropsylla cubana Crawford (Hemiptera: Psyllidae) as a pest in silvopastoral systems with this legume. This psyllid is known to be the main phytophagous pest (Valenciaga, 2003), which produces damage in 95% of the apical region of branches. Since information on the identification and biology of a pest species is a necessary prerequisite for its management, a taxonomic, biological and ecological study was conducted to define Heteropsylla behaviour in Cuban conditions and elaborate …

Effects Of Landscape Structure On Plants Species Richness In Small Grassland Remnants In Two Different Landscapes, S. A. O. Cousins, O. Eriksson

IGC Proceedings (1997-2023)

There is an increasing interest in using the landscape as the operational scale in many ecological studies. Current species richness in the landscape may be explained by past land use, and habitats may harbour species favoured by an environment that no longer exists. In this study we have included both a landscape scale and a temporal scale. The objective was to explain species pattern and the effect of isolation, habitat size and surrounding land use, and past land use change, on small grassland remnants in rural landscapes.

Invasion Dynamics Of The Exotic Liana Euonymus Fortunei (Turcz.) Hand.-Mazz. (Wintercreeper), Todd J. Rounsaville

Theses and Dissertations--Biology

Elevated atmospheric CO₂ has been implicated as a driver of increased liana abundance worldwide. Known as disturbance creators and beneficiaries, lianas possess the potential to significantly influence forest ecosystems. I investigated the early-invasion dynamics of Euonymus fortunei (wintercreeper), an evergreen liana that is invading forests in eastern North America, disrupting native plant communities and ecosystem functions.

Wintercreeper is widely cultivated as an ornamental groundcover, frequently invading natural areas via asexual stem growth. Invasion of remote natural areas is dependent upon seed transport and may occur less frequently. I examined the mechanisms of seed dormancy by conducting a ‘move-along’ experiment …

A Plant Trait-Based Approach To Evaluate The Ability Of Native C3 And C4 Grasses To Restore Functionality To A Remnant Bluegrass Savanna-Woodland In Kentucky, Usa., Jann E. Fry

Theses and Dissertations--Biology

Temperate Midwestern oak savannas are considered imperiled ecosystems with < 1 % remaining since the time of European settlement and are identified as critical areas for preservation. Restoration of Midwestern oak savannas is challenging due to the lack of accurate historical data, few intact remnants remaining to study, and lack of restoration ecology studies. A plant trait-based approach was used to evaluate the ability of six C₃ and three C₄ native bunchgrasses to restore functionality to a remnant savanna–woodland of the Bluegrass Region of Kentucky. The response and effect framework was used to assess the response of the nine native grasses according to the habitat filters of interannual precipitation, inter- vs. intra-specific competition, and simulated grazing. The effect traits associated with plant-soil nitrogen and carbon cycling were also assessed. The response traits of interannual competition and inter- vs. intra-specific competition along with the effect traits plant-soil nitrogen and carbon cycling were measured in a monoculture experiment …