scholarly journals Changes in Vegetation of Flooded Savannas Subject to Cattle Grazing and Fire in Plains of Colombia

Land ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 108
Author(s):  
Alejandro Huertas Herrera ◽  
Brigitte L. G. Baptiste Ballera ◽  
Mónica D. R. Toro-Manríquez ◽  
María V. Lencinas ◽  
Guillermo J. Martínez Pastur ◽  
...  
Keyword(s):  
Native Species ◽  
Multivariate Analyses ◽  
Vascular Plant ◽  
Cattle Grazing ◽  
Stocking Rate ◽  
Natural Ecosystems ◽  
Species List ◽  
Burn Treatment ◽  
Eastern Area ◽  
Palatable Species

Cattle grazing and fire are common types of management on natural ecosystems, generating several threats to the conservation of native vegetation (e.g., changes in species richness, cover, and abundance, mainly of bovine-palatable species). In this work, we analysed the response of the structure and composition of vegetation managed with different cattle stocking rates and fire in the savanna ecosystems of Colombia. The study was located in the eastern area of the Llanos region, where savannas were subjected to grazing and burning. Regarding grazing, we classified the area according to the cattle stocking rate (Bos indicus ~300 kg): NG = non-grazed, LS = low stocking rate (0.5 ind ha−1 yr−1), and HS = high stocking rate (1.0 ind ha−1 yr−1). Controlled artificial burning was applied in all the area at the beginning of the study, and surveys were conducted in the same plots at pre-burn (t0) and four post-burn times (t1, t2, t3, t4), at 15, 45, 75 and 105 days after burning. Vegetation composition (species list, life-form, palatability) and structure (bare soil and vascular plant ground covers, species height and richness) were recorded at each sampling. Data were compared through ANOVAs and multivariate analyses. We found 53 species in total: 26 in the pre-burn treatment and 44 in the post-burn treatments, detecting an increase of 18 species considering all treatments. Seven natives and two exotic species represented the dominant cover (>50%). LS and HS had the highest number of palatable species in t0 (seven species) compared with NG (two species), but this became similar after burning (14 species in NG, 12 in LS, and 11 in HS). ANOVAs and multivariate analyses showed that plant assemblages were significantly different according to the grazing treatment, and more homogeneous in pre-burn than in post-burn periods. Cattle grazing favored higher covers of dominant palatable species (e.g., Axonopus purpusii) compared with NG, but many native species with high palatability only recovered within the system after burning. In the context of the current management proposals, the search for new alternatives other than intensive cattle grazing and burning is needed to reconcile human production activities, international commitments against climate change and biodiversity conservation in the savanna landscapes.

Forestry practices and biodiversity, with particular reference to the Maritime Provinces of eastern Canada

1994 ◽  
Vol 2 (1) ◽  
pp. 33-77 ◽  
Author(s):  
Bill Freedman ◽  
Stephen Woodley ◽  
Judy Loo
Keyword(s):  
Native Species ◽  
Forest Products ◽  
Natural Ecosystems ◽  
Eastern Canada ◽  
Old Growth ◽  
Industrial Facilities ◽  
Levels Of Organization ◽  
Forestry Practices ◽  
Forest Industries ◽  
Ecologically Sustainable

The Canadian forest industries are based on the extensive harvesting and management of forests, with attendant effects on biodiversity at all levels of organization. In large part, conflicts between forestry and biodiversity occur because lands that are harvested and managed are mostly natural and seminatural ecosystems. Prior to being affected by forestry, such lands provided habitat for native species of wild life and their communities. Some of these elements of biodiversity may not find silvicultural habitats, especially plantations, to be suitable to their needs. In addition, the longer term integrity of some natural ecosystems, for example old-growth forests, is not compatible with any but the softest types of exploitation and management. This report discusses interactions of forestry and biodiversity at three levels of organization: (i) genetic variation within populations and species; (ii) the richness of species within communities; and (iii) the richness of community types on the landscape. A broader conclusion of our report is the following: If forestry systems of harvesting and management are to be practised in an ecologically sustainable fashion, then all elements of biodiversity must be accommodated within a landscape comprised of an integration of working lands and ecological reserves. The spatial scale of this integration could be various, ranging from large watersheds, to the "woodsheds" of particular industrial facilities, to provincial and national areas. Therefore, resolution of the substantial conflicts between biodiversity and forestry requires the design of ecologically sustainable landscapes that can provide a flow of timber and other valuated forest products, while still sustaining natural biodiversity resources.Key words: forest management, biodiversity, ecological reserves, eastern Canada, harvesting practices, old growth.

The Biology of Invasive Alien Plants in Canada. 4. Heracleum mantegazzianum Sommier & Levier

2006 ◽  
Vol 86 (2) ◽  
pp. 569-589 ◽  
Author(s):  
Nicholas A. Page ◽  
Ronald E. Wall ◽  
Stephen J. Darbyshire ◽  
Gerald A. Mulligan
Keyword(s):  
British Columbia ◽  
Urban Areas ◽  
Native Species ◽  
Invasive Plant ◽  
Leaf Shape ◽  
Herbarium Specimens ◽  
Natural Ecosystems ◽  
Alien Plant ◽  
Invasive Alien Plant ◽  
Heracleum Mantegazzianum

Heracleum mantegazzianum (giant hogweed) is an invasive alien plant of management concern in southern Canada where it has escaped from horticulture and established and spread in natural, ruderal, and agricultural ecosystems. It poses a threat to natural ecosystems and human health, and is also a weed in agricultural and urban areas. It is a member of the Carrot family (Apiaceae) and is closely related to the native species Heracleum maximum Bartram (cow-parsnip). It is a monocarpic perennial, which generally flowers in its 3rd or 4th year. Large size, leaf shape, dark reddish pigments in patches on stems and petioles, and fruit characteristics readily distinguish H. mantegazzianum from other plants in Canada. It is increasingly common in riparian areas, floodplains, and forest edges in or near urban areas in southwestern British Columbia and southern Ontario. Based on herbarium specimens, H. mantegazzianum was first recorded in Ontario in 1949, British Columbia in 1964, Nova Scotia in 1980, Quebec in 1990, and New Brunswick in 2000. The development of dense stands of H. mantegazzianum can also reduce the richness of native plants. Contact with H. mantegazzianum can cause phytophotodermatitis, a serious skin inflammation caused by UV photo-activation of furanocoumarins present in the sap. Control methods include herbicide application, mechanical cutting, and animal grazing, but strategies to address seed dispersal and re-establishment from dormant seed must also be adopted. Widespread establishment in southern Canada suggests that eradication is unlikely. However, range expansion and rapid population growth can be prevented through strategic management including public education. Key words: Giant hogweed, Heracleum mantegazzianum, Apiaceae, HERMZ, invasive plant, weed biology, furanocoumarins

Stocking rate effects on sheep and forage productivity under rubber in Malaysia

1997 ◽  
Vol 128 (3) ◽  
pp. 339-346 ◽  
Author(s):  
D. T. CHONG ◽  
I. TAJUDDIN ◽  
Abd. M. S. SAMAT ◽  
W. W. STÜR ◽  
H. M. SHELTON
Keyword(s):  
Cover Crops ◽  
Light Transmission ◽  
Stocking Rate ◽  
Kuala Lumpur ◽  
Low Light ◽  
Mikania Micrantha ◽  
Naturally Occurring ◽  
Rate Effects ◽  
Palatable Species ◽  
Stocking Rates

The productivity of grazing sheep was assessed under 7-year-old rubber at the Rubber Research Institute of the Malaysia Experimental Station at Sungai Buloh near Kuala Lumpur between October 1988 and May 1990. The sheep were Dorset × Marlin crossbred lambs and they grazed planted leguminous cover crops and naturally occurring species at a range of stocking rates.In the immature rubber trial, presentation yields of forage declined with time regardless of stocking rate. In the mature rubber trial, presentation yields of forage were low (<1000 kg/ha) due to low light transmission. High stocking rates (>6 sheep/ha) resulted in a decrease in the proportion of palatable species, namely Pueraria phaseoloides, Paspalum conjugatum, Asystasia gangetica and Mikania micrantha and an increase in the proportion of the less palatable species such as Calopogonium caeruleum and Cyrtococcum oxyphyllum.Daily liveweight gains ranged from 100 g/lamb per day at 4 sheep/ha to 70 g/lamb per day at 14 sheep/ha in the immature rubber trial. Only the lowest stocking rate of 2 sheep/ha was continuously sustainable in the mature rubber trial. The estimated maximum liveweight gain that could be achieved under immature rubber was 266 kg/ha per year at a stocking rate of 13·2 sheep/ha.

Nature as a theme in Canadian literature

2005 ◽  
Vol 13 (4) ◽  
pp. 169-197 ◽  
Author(s):  
Kate Turner ◽  
Bill Freedman
Keyword(s):  
Native Species ◽  
Environmental Literacy ◽  
Natural World ◽  
Environmental Damage ◽  
Natural Ecosystems ◽  
Canadian Literature ◽  
Literary Expression ◽  
Nature Literature ◽  
Century Poetry ◽  
Literature Culture

The relationships of people with the natural world are expressed in diverse ways, including painting, photographs, sculpture, song, video, and literature. In this document, we review historical and contemporary portrayals of nature as a theme in Canadian literature. Our assessment is intended to explore how Canadians have articulated their feelings about nature through literary expression, and to thereby gain insight into their empathy for natural ecosystems and native species, and their concern about damage caused to those values. We begin with a broad overview of nature as a theme in cultural expression, including overarching ones in Canadian literature, and discuss the influential literary views of Northrop Frye, Margaret Atwood, and their critics. We then examine the expression of nature within seven focal areas: early aboriginal expression, narratives of explorers, stories of settlers, the genre of animal stories, 20th-century poetry, recent aboriginal literature, and environmental ideas in contemporary prose. We identify six dominant themes of the expression of nature in Canadian literature: (1) humans as a part of nature; (2) a bounty of natural resources; (3) fear of an adversarial wilderness; (4) improvement of nature; (5) regret of environmental damage and perhaps despair of the future; and (6) love and respect of species and natural landscapes. Finally, we discuss how nature as a theme embedded in Canadian literature can be harnessed to further the compelling objectives of environmental literacy by providing sympathetic insights into the relationships of people and society with the species and ecosystems with which they share Canada.Key words: nature, literature, culture, Canada, environmental literacy.

Organic Matter Cycling

2006 ◽  
Author(s):  
Thomas S. Bianchi
Keyword(s):  
Organic Matter ◽  
Salt Marshes ◽  
Vascular Plant ◽  
World Ocean ◽  
Analytical Techniques ◽  
Marine Biota ◽  
Natural Ecosystems ◽  
Redfield Ratio ◽  
Structural Support ◽  
Transformation Of Organic Matter

In this chapter the general processes involved in controlling production and transformation of organic matter will be discussed as well as some of the associated stoichiometric changes of a few key biological elements (e.g., C, N, P, S). Stoichiometry is defined as the mass balance of chemical reactions as they relate to the law of definite proportions and conservation of mass (Sterner and Elser, 2002). For example, if we examine the average atomic ratios of C, N, and P in phytoplankton we see a relatively consistent ratio of 106:16:1 in most marine species. This is perhaps the best example of applied stoichiometric principles in natural ecosystems and is derived from the classic work of Alfred C. Redfield (1890–1983) (Redfield, 1958; Redfield et al., 1963). More specifically, Redfield compared the ratios of C, N, and P of dissolved nutrients in marine waters to that of suspended marine particulate matter (seston) (essentially phytoplankton) and found straight lines with equal slopes (figure 8.1; Redfield et al., 1963). This relationship suggested that marine biota were critical in determining the chemistry of the world ocean, clearly one of the most important historical findings linking chemical and biological oceanography (Falkowski, 2000). Moreover, the Redfield ratio has been further validated with recent data using improved analytical techniques (Karl et al., 1993; Hoppema and Goeyens, 1999). Other work has shown that there are predictable deviations from the Redfield ratio across a freshwater to open ocean marine gradient (figure 8.2; Downing, 1997). For example, N-to-P ratios in estuaries have commonly been shown to be lower and/or higher than the predicted Redfield ratio because of denitrification and anthropogenic nutrient enrichment processes, respectively. Inputs of vascular plant organic matter (e.g., mangroves, salt marshes, seagrasses) to estuarine systems presents another problem in causing deviations of C:N:P from the Redfield ratio. Vascular plants have been shown to deviate from this ratio in part because of relatively high amounts of C and N compared to algae due to a higher abundance of structural support molecules (e.g., cellulose, lignin) and defense antiherbivory (secondary) compounds (e.g., tannins), respectively (Vitousek et al., 1988).

scholarly journals Mapping the patchy legislative landscape of non-native tree species in Europe

2020 ◽  
Vol 93 (4) ◽  
pp. 567-586 ◽  
Author(s):  
Elisabeth Pötzelsberger ◽  
Katharina Lapin ◽  
Giuseppe Brundu ◽  
Tim Adriaens ◽  
Vlatko Andonovski ◽  
...  
Keyword(s):  
Native Species ◽  
Ad Hoc ◽  
Forest Sector ◽  
The European Union ◽  
Natural Ecosystems ◽  
Negative Effects ◽  
Regulatory Intensity ◽  
Negative Impacts ◽  
Legal Frameworks ◽  
June July

Abstract Europe has a history rich in examples of successful and problematic introductions of trees with a native origin outside of Europe (non-native trees, NNT). Many international legal frameworks such as treaties and conventions and also the European Union have responded to the global concern about potential negative impacts of NNT that may become invasive in natural ecosystems. It is, however, national and regional legislation in particular that affects current and future management decisions in the forest sector and shapes the landscapes of Europe. We identified all relevant legal instruments regulating NNT, the different legal approaches and the regulatory intensity in 40 European countries (no microstates). Information on hard and effective soft law instruments were collected by means of a targeted questionnaire and consultation of international and national legislation information systems and databases. In total, 335 relevant legal instruments were in place in June/July 2019 to regulate the use of NNT in the investigated 116 geopolitical legal units (countries as well as sub-national regions with their own legislation). Countries and regions were empirically categorized according to ad hoc-defined legislation indicators. These indicators pay respect to the general bans on the introduction of non-native species, the generally allowed and prohibited NNT, approval mechanisms and specific areas or cases where NNT are restricted or prohibited. Our study revealed a very diverse landscape of legal frameworks across Europe, with a large variety of approaches to regulating NNT being pursued and the intensity of restriction ranging from very few restrictions on species choice and plantation surface area to the complete banning of NNT from forests. The main conclusion is that there is a clear need for more co-ordinated, science-based policies both at the local and international levels to enhance the advantages of NNT and mitigate potential negative effects.

scholarly journals The response of Arctic vegetation and soils following an unusually severe tundra fire

2013 ◽  
Vol 368 (1624) ◽  
pp. 20120490 ◽  
Author(s):  
M. Syndonia Bret-Harte ◽  
Michelle C. Mack ◽  
Gaius R. Shaver ◽  
Diane C. Huebner ◽  
Miriam Johnston ◽  
...  
Keyword(s):  
Soil Nitrogen ◽  
Native Species ◽  
Vegetation Change ◽  
Nitrogen Availability ◽  
Net Primary Productivity ◽  
Plant Biomass ◽  
Vascular Plant ◽  
The Arctic ◽  
Soil Nitrogen Availability ◽  
Tussock Tundra

Fire causes dramatic short-term changes in vegetation and ecosystem function, and may promote rapid vegetation change by creating recruitment opportunities. Climate warming likely will increase the frequency of wildfire in the Arctic, where it is not common now. In 2007, the unusually severe Anaktuvuk River fire burned 1039 km 2 of tundra on Alaska's North Slope. Four years later, we harvested plant biomass and soils across a gradient of burn severity, to assess recovery. In burned areas, above-ground net primary productivity of vascular plants equalled that in unburned areas, though total live biomass was less. Graminoid biomass had recovered to unburned levels, but shrubs had not. Virtually all vascular plant biomass had resprouted from surviving underground parts; no non-native species were seen. However, bryophytes were mostly disturbance-adapted species, and non-vascular biomass had recovered less than vascular plant biomass. Soil nitrogen availability did not differ between burned and unburned sites. Graminoids showed allocation changes consistent with nitrogen stress. These patterns are similar to those seen following other, smaller tundra fires. Soil nitrogen limitation and the persistence of resprouters will likely lead to recovery of mixed shrub–sedge tussock tundra, unless permafrost thaws, as climate warms, more extensively than has yet occurred.

scholarly journals Nutritional adaptations of native plants of the cerrado biome in acid soils

2008 ◽  
Vol 20 (3) ◽  
pp. 183-195 ◽  
Author(s):  
Mundayatan Haridasan
Keyword(s):  
Native Species ◽  
Native Plants ◽  
Acid Soils ◽  
Common Species ◽  
Cultivated Plants ◽  
Soil Conditions ◽  
Nutrient Deficiencies ◽  
Natural Ecosystems ◽  
Native Communities ◽  
Cerrado Biome

Soils of the cerrado biome, mostly oxisols and deep sandy entisols, are acid, dystrophic and poor in available nutrients. These soils are not very different from soils that occur in the Amazon region. However, the open savanna physiognomies of cerrado with lower biomass of their different components are deficient in nutrients at the ecosystem level, unlike the Amazon forests which retain high nutrient reserves in their live biomass. Field crops are susceptible to aluminum and manganese toxicities, besides nutrient deficiencies, in cerrado soils and do not grow well in the absence of liming and fertilization. However, concepts of nutrient deficiencies and toxicities, well established for cultivated plants, should not be extended to native species in natural ecosystems, indiscriminately. Many native plants in the cerrado biome are resistant or tolerant to soil conditions deemed unfavorable for cultivated plants but their geographic distribution, frequency in native communities, growth and productivity are determined by water and nutrient availability and other edaphic conditions. Species growing on acid soils are aluminum tolerant or resistant, since their capacity to absorb essential nutrients, growth and reproduction is not affected by high aluminum levels in the soil. Many common species of the cerrado, instead of excluding aluminum, absorb and transport it to leaves and accumulate it in different tissues including leaves and seeds whereas others do not survive in the absence of exchangeable aluminum, even though no specific role of Al in plant metabolism is yet established.

Kentucky Bluegrass Invasion Alters Soil Carbon and Vegetation Structure on Northern Mixed-Grass Prairie of the United States

2017 ◽  
Vol 10 (01) ◽  
pp. 9-16 ◽  
Author(s):  
Matt A. Sanderson ◽  
Holly Johnson ◽  
Mark A. Liebig ◽  
John R. Hendrickson ◽  
Sara E. Duke
Keyword(s):  
Vegetation Structure ◽  
Native Species ◽  
Vegetation Change ◽  
Kentucky Bluegrass ◽  
The United States ◽  
Total Carbon ◽  
Stocking Rate ◽  
Soil C ◽  
Exotic Grasses

Invasive nonnative grasses pose a significant threat to rangelands of the Northern Great Plains. Long-term data from a grazing experiment near Mandan, ND (46°46′11.43″N, 100°54′55.16″W) revealed the invasion of native prairie by Kentucky bluegrass, an exotic grass. We hypothesized that bluegrass invasion altered soil13C and15N levels, tracking the increased abundance of invasive cool-season grass aboveground. In 2014, soil samples were collected to depths of 0 to 7.6 cm and 7.6 to 15.2 cm in pastures grazed similarly since 1916. Samples were analyzed for total carbon (C) and nitrogen (N) and13C and15N isotopes and compared against archived samples from 1991. Vegetation change from native to exotic grasses changed the isotopic composition of soil C. The soil δ13C at the 0- to 7.6-cm depth became more negative between 1991 and 2014. Soil δ13C became less negative with increasing stocking rate at both soil depths. Soil δ15N values at the 0- to 7.6-cm depth decreased between 1991 and 2014. Soil δ15N increased with increasing stocking rate at the 0- to 7.6-cm depth in 2014. Soil C and N concentrations at 0 to 7.6 cm increased by 35% (12 g C kg−1) and 27% (0.9 g N kg−1), respectively, from 1991 to 2014; however, concentrations at the 7.6- to 15.2-cm depth did not change. The shift from native C4to invasive C3grass did not reduce soil C storage in the long-term prairie pastures. The more deleterious effect of invasion, however, may have been the buildup of dead biomass, which alters vegetation structure and may reduce native species’ diversity and abundance.

Ant (Hymenoptera: Formicidae) diversity in savanna ecosystem: a comparison of sampling methods and seasons

2020 ◽  
Vol 14 (1) ◽  
pp. 6-15
Author(s):  
CEBISILE N. MAGAGULA
Keyword(s):  
Sampling Methods ◽  
Direct Search ◽  
Natural Ecosystems ◽  
Pitfall Trapping ◽  
Conservation Areas ◽  
Species List ◽  
Species Lists ◽  
Important Means ◽  
Unique Species ◽  
Biodiversity Information

One of the most important means of obtaining biodiversity information in natural ecosystems is surveying and collection of biological specimen using appropriate sampling methods. This study was carried out to determine the most appropriate sampling method for ants in a savanna ecosystem during two distinct seasons. Pitfall trapping, direct search and litter extrac­tion produced significantly different species lists, with each method having unique species and seasons also showed the same trend. A total of 53 species were collected from both conservation areas during the study, with Pheidole sp.4, Crematogaster amita and Monomorium albopilosum being the three most dominant species. Generalised Myrmicinae and opportunists were the functional groups with the highest species richness in all methods and seasons, with pitfall trapping having the highest richness. While pitfall trapping and direct search were deemed to be the most efficient methods in this savanna, results also suggest that varied sampling methods are necessary to ensure sampling of all microhabitats within a specific locality. Ad­ditionally, utilisation and testing of sampling methods is essential for each geographic region.Key words: Sampling, biodiversity assessment, species list, insects, Formicidae, ants, savanna

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