Grazing exclusion effects on vegetation structure and soil organic matter in savannas of Río de la Plata grasslands

IF 2.2 3区环境科学与生态学 Q2 ECOLOGY

Journal of Vegetation Science Pub Date : 2024-09-16 DOI:10.1111/jvs.13304

Micaela Abrigo, Felipe Lezama, Iván Grela, Gervasio Piñeiro

{"title":"Grazing exclusion effects on vegetation structure and soil organic matter in savannas of Río de la Plata grasslands","authors":"Micaela Abrigo, Felipe Lezama, Iván Grela, Gervasio Piñeiro","doi":"10.1111/jvs.13304","DOIUrl":null,"url":null,"abstract":"<div>\n \n \n <section>\n \n <h3> Questions</h3>\n \n <p>Herbivores change plant communities and biogeochemical cycles by changing species composition and soil organic matter contents through different mechanisms. Our objective was to evaluate the effects of livestock removal on plant species composition and soil organic matter stocks in savannas of the Río de la Plata grasslands.</p>\n </section>\n \n <section>\n \n <h3> Locations</h3>\n \n <p>A subtropical savanna in Río Negro, Uruguay.</p>\n </section>\n \n <section>\n \n <h3> Methods</h3>\n \n <p>The experiment consisted of a paired grazing exclusion randomized block design with five sites, where livestock was excluded for 29 years. We recorded differences in plant species composition in different strata and extracted soil cores to analyze soil carbon and nitrogen stocks, and δ<sup>13</sup> carbon contents in two different soil organic matter fractions.</p>\n </section>\n \n <section>\n \n <h3> Results</h3>\n \n <p>Long-term livestock removal reduced plant species richness and diversity, altered the floristic composition and facilitated native-shrub encroachment. Grazing exclusion modified the relative frequency of plant functional types and reduced summer-growing grasses. We recorded 45 species common to both grazing and exclosure treatments, while 19 were present only in exclosure sites and 39 only in grazed sites. Livestock exclusion had a differential effect on soil organic matter formation, increased soil organic carbon and nitrogen stocks in the mineral-associated organic matter (MAOM) but tended to slightly reduce them in the particulate organic matter fraction (POM). Grazing removal modified the C<sub>3</sub>/C<sub>4</sub> species cover and these differences were reflected in the δ<sup>13</sup>C contents of both POM and MAOM fractions.</p>\n </section>\n \n <section>\n \n <h3> Conclusions</h3>\n \n <p>Removal of domestic herbivores increased shrub abundance, decreased plant species richness and diversity but increased total carbon and nitrogen contents in soil organic matter. Our results suggest that grazed and exclosure areas should be combined mosaically in the landscape to maximize plant species diversity and soil organic carbon sequestration.</p>\n </section>\n </div>","PeriodicalId":49965,"journal":{"name":"Journal of Vegetation Science","volume":"35 5","pages":""},"PeriodicalIF":2.2000,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Vegetation Science","FirstCategoryId":"93","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1111/jvs.13304","RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ECOLOGY","Score":null,"Total":0}

引用次数: 0

Abstract

Questions

Herbivores change plant communities and biogeochemical cycles by changing species composition and soil organic matter contents through different mechanisms. Our objective was to evaluate the effects of livestock removal on plant species composition and soil organic matter stocks in savannas of the Río de la Plata grasslands.

Locations

A subtropical savanna in Río Negro, Uruguay.

Methods

The experiment consisted of a paired grazing exclusion randomized block design with five sites, where livestock was excluded for 29 years. We recorded differences in plant species composition in different strata and extracted soil cores to analyze soil carbon and nitrogen stocks, and δ¹³ carbon contents in two different soil organic matter fractions.

Results

Long-term livestock removal reduced plant species richness and diversity, altered the floristic composition and facilitated native-shrub encroachment. Grazing exclusion modified the relative frequency of plant functional types and reduced summer-growing grasses. We recorded 45 species common to both grazing and exclosure treatments, while 19 were present only in exclosure sites and 39 only in grazed sites. Livestock exclusion had a differential effect on soil organic matter formation, increased soil organic carbon and nitrogen stocks in the mineral-associated organic matter (MAOM) but tended to slightly reduce them in the particulate organic matter fraction (POM). Grazing removal modified the C₃/C₄ species cover and these differences were reflected in the δ¹³C contents of both POM and MAOM fractions.

Conclusions

Removal of domestic herbivores increased shrub abundance, decreased plant species richness and diversity but increased total carbon and nitrogen contents in soil organic matter. Our results suggest that grazed and exclosure areas should be combined mosaically in the landscape to maximize plant species diversity and soil organic carbon sequestration.

Abstract Image

查看原文本刊更多论文

放牧排斥对拉普拉塔河草原稀树草原植被结构和土壤有机质的影响

问题食草动物通过不同的机制改变物种组成和土壤有机质含量，从而改变植物群落和生物地球化学循环。我们的目标是评估清除牲畜对拉普拉塔河草原稀树草原植物物种组成和土壤有机质储量的影响。地点乌拉圭里奥内格罗的亚热带稀树草原。实验方法实验采用配对放牧排除随机区组设计，共设五个地点，在 29 年的时间里禁止牲畜进入。我们记录了不同地层植物物种组成的差异，并提取土壤岩心分析土壤碳和氮储量，以及两种不同土壤有机质组分中的δ13碳含量。结果长期放牧降低了植物物种的丰富度和多样性，改变了植物组成，并促进了本地灌木的蚕食。放牧排斥改变了植物功能类型的相对频率，并减少了夏季生长的草类。我们记录了放牧和围栏处理中常见的 45 种植物，其中 19 种仅出现在围栏地点，39 种仅出现在放牧地点。牲畜隔离对土壤有机质的形成有不同的影响，增加了矿物相关有机质（MAOM）中的土壤有机碳和氮储量，但往往略微减少了颗粒有机质（POM）中的土壤有机碳和氮储量。放牧改变了 C3/C4 物种的覆盖率，这些差异反映在 POM 和 MAOM 部分的 δ13C 含量上。结论清除家养食草动物增加了灌木丰度，降低了植物物种丰富度和多样性，但增加了土壤有机质中的总碳和总氮含量。我们的研究结果表明，应在景观中将放牧区和围栏区镶嵌在一起，以最大限度地提高植物物种多样性和土壤有机碳固存。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

求助全文

约1分钟内获得全文求助全文

来源期刊

Journal of Vegetation Science 环境科学-林学

CiteScore

6.00

自引率

3.60%

发文量

审稿时长

2 months

期刊介绍： The Journal of Vegetation Science publishes papers on all aspects of plant community ecology, with particular emphasis on papers that develop new concepts or methods, test theory, identify general patterns, or that are otherwise likely to interest a broad international readership. Papers may focus on any aspect of vegetation science, e.g. community structure (including community assembly and plant functional types), biodiversity (including species richness and composition), spatial patterns (including plant geography and landscape ecology), temporal changes (including demography, community dynamics and palaeoecology) and processes (including ecophysiology), provided the focus is on increasing our understanding of plant communities. The Journal publishes papers on the ecology of a single species only if it plays a key role in structuring plant communities. Papers that apply ecological concepts, theories and methods to the vegetation management, conservation and restoration, and papers on vegetation survey should be directed to our associate journal, Applied Vegetation Science journal.