Pub Date : 2019-12-01DOI: 10.4067/s0718-686x2019000300049
V. Bermanec, Ž. Fiket, J. Hrenović, S. Kazazić, G. Kniewald, C. Venter, A. Botha
Received: Jun. 05, 2019 Accepted: Sep. 09, 2019 Abstract The appearance and spread of antibiotic resistance are considered a highly complex process with many factors affecting the resistance mechanisms, including metals. In order to fully understand the spread of antibiotic resistance in different environments, combined studies including geochemistry and microbiology are becoming imperative. So far, very few such studies have been conducted, and none of them involves the southernmost regions. The aim of this study was, therefore, to examine the biogeochemical characteristics of sediments of the southernmost part of Chile. Sediment geochemistry, as well as the presence of heterotrophic and carbapenemresistant bacteria (CRB) in the Río de las Minas and neighbouring Strait of Magellan in Punta Arenas (Chile), was investigated to assess the anthropogenic impact of untreated urban wastewater on the accumulation of metals and microbial contaminants in this coastal system. Geochemistry of sediments indicated the influence of both natural processes and anthropogenic activities. Although levels of metals in sediments currently do not represent a toxic effect on organisms, the anthropogenic influence on the sediment composition in the study area cannot be denied. Clinically relevant CRB were found in river sediments (1.9 and 2.7 log CFU / mL). Our findings suggest that the Río de las Minas is under the anthropogenic impact of untreated urban wastewater and represent a significant source of potentially pathogenic CRB to the local environment.
摘要抗生素耐药性的出现和传播被认为是一个高度复杂的过程，影响耐药机制的因素很多，包括金属因素。为了充分了解抗生素耐药性在不同环境下的传播，包括地球化学和微生物学在内的综合研究变得势在必行。到目前为止，很少进行这样的研究，而且没有一项研究涉及最南端的地区。因此，这项研究的目的是检查智利最南端沉积物的生物地球化学特征。研究了智利蓬塔阿雷纳斯(Punta Arenas) Río de las Minas和邻近的麦哲伦海峡中沉积物的地球化学特征，以及异养细菌和抗碳霉烯类细菌(CRB)的存在，以评估未经处理的城市废水对该沿海系统中金属和微生物污染物积累的人为影响。沉积物的地球化学特征表明自然过程和人为活动的双重影响。虽然目前沉积物中的金属含量并不代表对生物体有毒性作用，但人类活动对研究地区沉积物组成的影响是不可否认的。河流沉积物中存在与临床相关的CRB(1.9和2.7 log CFU / mL)。我们的研究结果表明，Río de las Minas受到未经处理的城市废水的人为影响，是当地环境中潜在致病性CRB的重要来源。
{"title":"Geochemical and microbiological characterization of sediments at the mouth of Río de las Minas (Punta Arenas, Chile)","authors":"V. Bermanec, Ž. Fiket, J. Hrenović, S. Kazazić, G. Kniewald, C. Venter, A. Botha","doi":"10.4067/s0718-686x2019000300049","DOIUrl":"https://doi.org/10.4067/s0718-686x2019000300049","url":null,"abstract":"Received: Jun. 05, 2019 Accepted: Sep. 09, 2019 Abstract The appearance and spread of antibiotic resistance are considered a highly complex process with many factors affecting the resistance mechanisms, including metals. In order to fully understand the spread of antibiotic resistance in different environments, combined studies including geochemistry and microbiology are becoming imperative. So far, very few such studies have been conducted, and none of them involves the southernmost regions. The aim of this study was, therefore, to examine the biogeochemical characteristics of sediments of the southernmost part of Chile. Sediment geochemistry, as well as the presence of heterotrophic and carbapenemresistant bacteria (CRB) in the Río de las Minas and neighbouring Strait of Magellan in Punta Arenas (Chile), was investigated to assess the anthropogenic impact of untreated urban wastewater on the accumulation of metals and microbial contaminants in this coastal system. Geochemistry of sediments indicated the influence of both natural processes and anthropogenic activities. Although levels of metals in sediments currently do not represent a toxic effect on organisms, the anthropogenic influence on the sediment composition in the study area cannot be denied. Clinically relevant CRB were found in river sediments (1.9 and 2.7 log CFU / mL). Our findings suggest that the Río de las Minas is under the anthropogenic impact of untreated urban wastewater and represent a significant source of potentially pathogenic CRB to the local environment.","PeriodicalId":207115,"journal":{"name":"Anales Del Instituto De La Patagonia","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123375713","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-12-01DOI: 10.4067/s0718-686x2019000300043
E. Faúndez, Máriom A. Carvajal, N. Asplanato, Flavia Raffo, Catalina J. Vargas
Received: Oct. 16, 2018 Accepted: Oct. 31, 2019 Abstract The presence of the spider Tegenaria domestica in southern Patagonia is revised and analyzed. New records are provided from Santa Cruz and Tierra del Fuego Province Argentina, and its presence is confirmed in Magallanes Region, Chile. The significance of the historical records and the new ones is discussed. Illustrations are provided to correctly identify the species.
{"title":"Contribution to the knowledge of Tegenaria domestica (Clerck, 1757) (Araneae: Agelenidae) in Southern Patagonia","authors":"E. Faúndez, Máriom A. Carvajal, N. Asplanato, Flavia Raffo, Catalina J. Vargas","doi":"10.4067/s0718-686x2019000300043","DOIUrl":"https://doi.org/10.4067/s0718-686x2019000300043","url":null,"abstract":"Received: Oct. 16, 2018 Accepted: Oct. 31, 2019 Abstract The presence of the spider Tegenaria domestica in southern Patagonia is revised and analyzed. New records are provided from Santa Cruz and Tierra del Fuego Province Argentina, and its presence is confirmed in Magallanes Region, Chile. The significance of the historical records and the new ones is discussed. Illustrations are provided to correctly identify the species.","PeriodicalId":207115,"journal":{"name":"Anales Del Instituto De La Patagonia","volume":"141 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115746509","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-12-01DOI: 10.4067/S0718-686X2018000300067
David R. Martínez
{"title":"The summer diet of the magellanic horned owl ( Bubo magellanicus , Gmelin, 1788) at the easternmost projection of continental Chile, Punta Dungeness","authors":"David R. Martínez","doi":"10.4067/S0718-686X2018000300067","DOIUrl":"https://doi.org/10.4067/S0718-686X2018000300067","url":null,"abstract":"","PeriodicalId":207115,"journal":{"name":"Anales Del Instituto De La Patagonia","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121111325","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-12-01DOI: 10.4067/S0718-686X2018000300051
R. Pinochet, J. Soto, M. Palacios, S. Oyarzún
Entre las causas que determinan preferencia alimentaria se destacan las propiedades de las dietas del consumidor o de la interaccion consumidor-presa. Debido al desafio que constituye incluir todos estos componentes para evaluar preferencia, es que se opto por una forma de medirla a traves de la seleccion de un tipo de alimento en particular. Esta seleccion fue basada en la tasa de consumo del alimento, asumiendo que aquellos que satisfagan mas rapido los requerimientos fisiologicos del organismo seran los que mas se consuman. Si existe seleccion por un tipo de alimento en particular, la tasa de consumo sobre ese alimento sera diferente si es presentado como mono dieta o dieta mixta. Con el fin de evaluar preferencia alimentaria en el caracol negro Tegula atra, se realizaron experimentos manipulativos de selectividad con individuos procedentes de dos localidades del sur del Chile: Bahia Metri (Puerto Montt) y Punta Santa Ana (Estrecho de Magallanes). Estos ejemplares fueron expuestos a mono dieta y dieta mixta de macroalgas. Los resultados de las tasas de consumo dan cuenta de la capacidad de este organismo de alimentarse de variadas especies de macroalgas, pero tambien de ciertos comportamientos selectivos, principalmente dado por el mayor consumo de la macroalga parda, Macrocystis pyrifera. Estos resultados concuerdan con la frecuencia en que se encuentran asociadas ambas especies en su ambiente natural
在决定食物偏好的原因中，我们强调了消费者饮食或消费者-猎物相互作用的特性。由于在评估偏好时包含所有这些成分的挑战，人们选择了一种通过选择特定类型的食物来衡量偏好的方法。这一选择是基于食物的消耗量，假设那些能更快地满足身体生理需求的食物将是那些消耗最多的食物。如果有一种特定类型的食物可供选择，那么这种食物的消费量将是不同的，无论是单一饮食还是混合饮食。为了评估黑蜗牛Tegula atra的食物偏好，我们对来自智利南部两个地点的个体进行了操纵选择性实验:Bahia Metri (Puerto Montt)和Punta Santa Ana (strain de Magallanes)。这些标本暴露在单一饲料和大型藻类混合饲料中。在本研究中，我们分析了这种生物以不同种类的大型藻类为食的能力，但也分析了某些选择性行为，主要是由于棕色大型藻类的消费量较高。这些结果与这两个物种在自然环境中被发现的频率一致
{"title":"Dietary selection of Tegula atra (Lesson, 1830) as an approximation of preference over different species of macroalgae from south of Chile","authors":"R. Pinochet, J. Soto, M. Palacios, S. Oyarzún","doi":"10.4067/S0718-686X2018000300051","DOIUrl":"https://doi.org/10.4067/S0718-686X2018000300051","url":null,"abstract":"Entre las causas que determinan preferencia alimentaria se destacan las propiedades de las dietas del consumidor o de la interaccion consumidor-presa. Debido al desafio que constituye incluir todos estos componentes para evaluar preferencia, es que se opto por una forma de medirla a traves de la seleccion de un tipo de alimento en particular. Esta seleccion fue basada en la tasa de consumo del alimento, asumiendo que aquellos que satisfagan mas rapido los requerimientos fisiologicos del organismo seran los que mas se consuman. Si existe seleccion por un tipo de alimento en particular, la tasa de consumo sobre ese alimento sera diferente si es presentado como mono dieta o dieta mixta. Con el fin de evaluar preferencia alimentaria en el caracol negro Tegula atra, se realizaron experimentos manipulativos de selectividad con individuos procedentes de dos localidades del sur del Chile: Bahia Metri (Puerto Montt) y Punta Santa Ana (Estrecho de Magallanes). Estos ejemplares fueron expuestos a mono dieta y dieta mixta de macroalgas. Los resultados de las tasas de consumo dan cuenta de la capacidad de este organismo de alimentarse de variadas especies de macroalgas, pero tambien de ciertos comportamientos selectivos, principalmente dado por el mayor consumo de la macroalga parda, Macrocystis pyrifera. Estos resultados concuerdan con la frecuencia en que se encuentran asociadas ambas especies en su ambiente natural","PeriodicalId":207115,"journal":{"name":"Anales Del Instituto De La Patagonia","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116741472","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-12-01DOI: 10.4067/s0718-686x2018000300073
Eduardo Almonacid Rioseco, Erik Daza Valdebenito, Ruth Hernández Rodríguez
{"title":"Situación pesquera del centollón Paralomis granulosa , (Hombron & Jacquinot, 1846) (Decapoda: Lithodidae) en Magallanes, Chile y consideraciones para mejorar el futuro manejo de la pesquería","authors":"Eduardo Almonacid Rioseco, Erik Daza Valdebenito, Ruth Hernández Rodríguez","doi":"10.4067/s0718-686x2018000300073","DOIUrl":"https://doi.org/10.4067/s0718-686x2018000300073","url":null,"abstract":"","PeriodicalId":207115,"journal":{"name":"Anales Del Instituto De La Patagonia","volume":"97 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115803183","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-12-01DOI: 10.4067/S0718-686X2018000300081
J. Cañete
{"title":"Polyzoa opuntia (Ascidiacea) in the Magellan Region, Chile: Colony shape changing with size and substrate","authors":"J. Cañete","doi":"10.4067/S0718-686X2018000300081","DOIUrl":"https://doi.org/10.4067/S0718-686X2018000300081","url":null,"abstract":"","PeriodicalId":207115,"journal":{"name":"Anales Del Instituto De La Patagonia","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124568495","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-12-01DOI: 10.4067/S0718-686X2018000300029
Nancy Calisto Ulloa, C. G. Fuentes, P. Muñoz
Antimicrobial resistant bacteria are widespread in aquatic environments. The aim of the present study was to obtain information on the occurrence of bacteria with antimicrobial resistance in seawater surrounding Antarctic stations. Escherichia coli strains were isolated from seawater. The samples were collected from sites distributed around the sewage outfalls of seven Antarctic stations. Antibiotic susceptibility patterns were determined with the disk diffusion method using different groups of antibiotics: penicillins, carbapenems, aminoglycosides, quinolones, tetracycline, phenicols and trimethoprim. Escherichia coli ATCC 25922 was used as the control for the susceptibility tests. A total of 216 samples were analysed. Escherichia coli were detected in 58 % of the samples. The highest bacterial counts were found in seawater surrounding the sewage outfalls. However, the bacterial counts decreased rapidly with increasing distance from the outfall. Seventy strains isolated were studied to determine antibiotic susceptibility. The strains studied showed resistant to 16 out of the 17 antibiotics tested. Thirty-six strains were susceptible to all the antibiotics tested Thirty-four were resistant to at least one antibiotic, 12 were multidrug resistant and 20 showed resistant to Ampicillin. Finally, the presence of extended-spectrum beta-lactamases (ESBLs) was determined in two strains studied The presence of bacteria with antimicrobial resistance in the Antarctic environment is indicative of how widespread the global antibiotic resistance situation has become.
{"title":"Resistencia a antibióticos en bacterias recolectadas en agua de mar en las proximidades de bases antárticas","authors":"Nancy Calisto Ulloa, C. G. Fuentes, P. Muñoz","doi":"10.4067/S0718-686X2018000300029","DOIUrl":"https://doi.org/10.4067/S0718-686X2018000300029","url":null,"abstract":"Antimicrobial resistant bacteria are widespread in aquatic environments. The aim of the present study was to obtain information on the occurrence of bacteria with antimicrobial resistance in seawater surrounding Antarctic stations. Escherichia coli strains were isolated from seawater. The samples were collected from sites distributed around the sewage outfalls of seven Antarctic stations. Antibiotic susceptibility patterns were determined with the disk diffusion method using different groups of antibiotics: penicillins, carbapenems, aminoglycosides, quinolones, tetracycline, phenicols and trimethoprim. Escherichia coli ATCC 25922 was used as the control for the susceptibility tests. A total of 216 samples were analysed. Escherichia coli were detected in 58 % of the samples. The highest bacterial counts were found in seawater surrounding the sewage outfalls. However, the bacterial counts decreased rapidly with increasing distance from the outfall. Seventy strains isolated were studied to determine antibiotic susceptibility. The strains studied showed resistant to 16 out of the 17 antibiotics tested. Thirty-six strains were susceptible to all the antibiotics tested Thirty-four were resistant to at least one antibiotic, 12 were multidrug resistant and 20 showed resistant to Ampicillin. Finally, the presence of extended-spectrum beta-lactamases (ESBLs) was determined in two strains studied The presence of bacteria with antimicrobial resistance in the Antarctic environment is indicative of how widespread the global antibiotic resistance situation has become.","PeriodicalId":207115,"journal":{"name":"Anales Del Instituto De La Patagonia","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124877355","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-12-01DOI: 10.4067/S0718-686X2018000300007
R. Molina, N. Soto, Ana Tapia
In 1946, the beaver (Castor canadensis Kuhl 1820) was introduced in the tip of South America, which has generated great ecological and economic impacts in the austral ecosystem and forests. Since the beavers were release, they have been in a constant expansion through Tierra del Fuego, austral archipelago and in the continental areas of the Magellan region. In 1999 the Servicio Agricola y Ganadero (SAG) has developed a line of work about invasive species that affect in the field of agricultural production in Magallanes. The purpose of this work was updating the information about the distirbution of the beaver populations in the continent and controlling the potential outbreaks. SAG has hired a service of the beaver prospection in more than 3000 km of riversides and application of surveys in livestocks farm. During prospection, a new sign of the beaver is detected, but in areas where the species was have been recorded previously. These results show that despite the migratory pulses from Tierra del Fuego, the population has not been established in the continental area detonating to agriculture proposed. Nevertheless the potential of detection in conditions of low density added to the modification in the construction of dams and burrows could help to interpret these results. The temporality of the watercourses and the presence
{"title":"Estado actual de la distribución del castor Castor canadensis Kuhl 1820 (Rodentia) en el área continental de la región de Magallanes, Chile","authors":"R. Molina, N. Soto, Ana Tapia","doi":"10.4067/S0718-686X2018000300007","DOIUrl":"https://doi.org/10.4067/S0718-686X2018000300007","url":null,"abstract":"In 1946, the beaver (Castor canadensis Kuhl 1820) was introduced in the tip of South America, which has generated great ecological and economic impacts in the austral ecosystem and forests. Since the beavers were release, they have been in a constant expansion through Tierra del Fuego, austral archipelago and in the continental areas of the Magellan region. In 1999 the Servicio Agricola y Ganadero (SAG) has developed a line of work about invasive species that affect in the field of agricultural production in Magallanes. The purpose of this work was updating the information about the distirbution of the beaver populations in the continent and controlling the potential outbreaks. SAG has hired a service of the beaver prospection in more than 3000 km of riversides and application of surveys in livestocks farm. During prospection, a new sign of the beaver is detected, but in areas where the species was have been recorded previously. These results show that despite the migratory pulses from Tierra del Fuego, the population has not been established in the continental area detonating to agriculture proposed. Nevertheless the potential of detection in conditions of low density added to the modification in the construction of dams and burrows could help to interpret these results. The temporality of the watercourses and the presence","PeriodicalId":207115,"journal":{"name":"Anales Del Instituto De La Patagonia","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125033791","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-12-01DOI: 10.4067/S0718-686X2018000300061
V. Pérez
The absence of the bumblebee Bombus dahlbomii Guerin-Meneville in Punta Arenas (Magallanes Region, Chile) during spring and summer (2017-2018) is reported. The analysis of current state of flora and vegetation, in addition to climatic record and theory of temporal window are not sufficient elements for explaining the absence of this apid. Historical bsckground is given to complete its nomenclatural card and to establish a possible status of no continuity of its specific existence. It is hypothesized that this bumblebee, for unknown reasons, should be beginning its extinction period.
{"title":"Noticia inquietante: ausencia del abejorro Bombus (Fervidobombus) dahlbomii guérin-méneville (Hymenoptera: Apidae) en la primavera 2017-verano 2018 de la ciudad de Punta Arenas (53 o 10’S; 70 o 55’O), Magallanes, Chile meridional, con antecedentes históricos de la especie","authors":"V. Pérez","doi":"10.4067/S0718-686X2018000300061","DOIUrl":"https://doi.org/10.4067/S0718-686X2018000300061","url":null,"abstract":"The absence of the bumblebee Bombus dahlbomii Guerin-Meneville in Punta Arenas (Magallanes Region, Chile) during spring and summer (2017-2018) is reported. The analysis of current state of flora and vegetation, in addition to climatic record and theory of temporal window are not sufficient elements for explaining the absence of this apid. Historical bsckground is given to complete its nomenclatural card and to establish a possible status of no continuity of its specific existence. It is hypothesized that this bumblebee, for unknown reasons, should be beginning its extinction period.","PeriodicalId":207115,"journal":{"name":"Anales Del Instituto De La Patagonia","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128047542","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-12-01DOI: 10.4067/S0718-686X2018000300017
Erwim Domínguez Díaz, G. Oliva, John Báez Madariaga, A. Navarro, Claudio Pérez Castillo
Naturalized grasslands in Magallanes are important but fragile agro-ecosystems that may change due to climatic variations and overgrazing. Holistic grazing (HG) has been introduced into Magallanes in 2013 as a new, management intensive technological alternative, that in principle would improve the health of grassland. Considering this, it is priority to generate scientific information and maintain a permanent follow-up on this type of management. The objective of this study was to analyze the effects on vegetation in order to assess whether holistic grazing degrades or improves the floristic structure and composition of naturalized grasslands. We compared three paddocks managed under grazing holistic (HG): La Campana, Lago Sofia and Parcela Tamara, with three equivalent areas under Semi-Intensive grazing (SIG), a traditional management in the area that includes rotations with short rests: Tres Pasos, Dos Lagos and Parcela Colonia Isabel Riquelme. All areas were ecologically equivalent and derived from substitution of nirre forests (Nothofagus antarctica (G. Forst.) Oerst.), and located in the province of Ultima Esperanza, with 389 mm annual rainfall. The study was conducted between 2014-18, with an average rainfall of 372 mm which is within normal for that area. The hypothesis was that the HG would increase the vegetation cover, palatable species cover and diversity. Vegetation and soil monitors were installed in three fields with HG and three SIG following the MARAS methodology. The results indicate that changes over the years were not significant in terms of cover (p>0.8450), but significant differences were observed in species richness (P 0.1710). In conclusion, plant cover increase was not detected for HG, but species dominance was rearranged, as palatable, exotic species, increased under HG. This is perhaps because grazing pressure decreased competition in the canopy, favoring naturalized exotic species such as white clover (Trifolium repens) that could not compete with invasive weeds like Achillea millefolium and Hieracium prealtum under SIG. Future trials should consider evaluating productive parameters such as forage availability, weight and animal health status.
麦哲伦草原是重要但脆弱的农业生态系统，可能因气候变化和过度放牧而发生变化。整体放牧(HG)作为一种新的管理密集型技术替代方案于2013年引入麦哲伦，原则上可以改善草原的健康状况。考虑到这一点，产生科学的信息并保持对这种管理的长期跟踪是优先考虑的。本研究的目的是分析全面放牧对植被的影响，以评估全面放牧是退化还是改善归化草地的植物区系结构和组成。我们比较了三个采用整体放牧(HG)管理的围场:La Campana、Lago Sofia和Parcela Tamara，以及三个采用半集约放牧(SIG)管理的等效区域，后者是一种传统的管理方式，包括短期休息的轮换:Tres Pasos、Dos Lagos和Parcela Colonia Isabel Riquelme。所有地区在生态上都是相当的，都是由替代的热带森林(Nothofagus antarctica (G. forest))产生的。)，位于Ultima Esperanza省，年降雨量为389毫米。该研究是在2014-18年间进行的，平均降雨量为372毫米，在该地区的正常范围内。假设HG会增加植被覆盖度、适口物种覆盖度和多样性。按照MARAS方法，在三个有HG和三个SIG的地区安装了植被和土壤监测仪。结果表明:各年际植被覆盖度变化不显著(p < 0.8450)，物种丰富度差异显著(p < 0.1710);综上所述，HG没有增加植物覆盖，但物种优势被重新安排，因为在HG下，适口的外来物种增加了。这可能是因为放牧压力减少了冠层内的竞争，有利于归化的外来物种，如白三叶草(Trifolium repens)，它们不能与入侵杂草(如Achillea milleium和Hieracium prealtum)竞争。体重和动物健康状况。
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