{"title":"Grasses don’t always win: Short-term effects of fertilization on taxonomic and functional diversity of a Mediterranean annual grassland","authors":"Melanie Köbel , Sergio Chozas , Gerardo Moreno , Mirco Migliavacca , Cristina Branquinho , Alice Nunes","doi":"10.1016/j.agee.2024.109125","DOIUrl":null,"url":null,"abstract":"<div><p>Nitrogen pollution has increased dramatically over the last decades, becoming a major contributor to biodiversity loss and compositional changes globally. While the main effects of excessive nutrients on plant communities are well established, Mediterranean grasslands have been less studied despite their high levels of biodiversity. Moreover, evidence has shown that the impacts of nutrients may depend on additional factors, namely soil conditions and grazing, increasing the uncertainty about the effects of increasing nutrient availability in these systems. In this work, we assessed the short-term effects (1 year) of fertilization in an extensively grazed oak open woodland (called <em>montado</em>, or <em>dehesa</em>), in Spain. Plots comprised a complete randomized design with four treatments: control (not fertilized), fertilization with nitrogen at a rate of 100 kg N ha<sup>−1</sup>, fertilization with phosphorous (50 kg P ha<sup>−1</sup>) and fertilization with both N and P (100 kg ha<sup>−1</sup> N + 50 kg ha<sup>−1</sup> P). We assessed changes in plant species composition and functional diversity and evaluated the association between species and fertilization treatments with an indicator species analysis. Our results showed that species diversity increased with NP fertilization and that forbs in particular increased in cover and richness. SLA and seed mass also showed differences compared to the control. The Community-weighted mean and functional dispersion of groups based on growth form and N-fixing ability were not influenced by fertilization. Two species were significantly associated with fertilized plots: the spiny forb <em>Carlina racemosa</em> and the latex-producing forb <em>Tolpis barbata</em>. Our study suggests that short-term fertilization may alleviate nutrient limitations in these systems, increasing plant diversity, although longer-term studies are needed to understand the effects of a continuous increase in nutrient availability.</p></div>","PeriodicalId":7512,"journal":{"name":"Agriculture, Ecosystems & Environment","volume":null,"pages":null},"PeriodicalIF":6.0000,"publicationDate":"2024-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0167880924002433/pdfft?md5=b6f5e76c11a5fd6551050499c4596710&pid=1-s2.0-S0167880924002433-main.pdf","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Agriculture, Ecosystems & Environment","FirstCategoryId":"97","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0167880924002433","RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"AGRICULTURE, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
Abstract
Nitrogen pollution has increased dramatically over the last decades, becoming a major contributor to biodiversity loss and compositional changes globally. While the main effects of excessive nutrients on plant communities are well established, Mediterranean grasslands have been less studied despite their high levels of biodiversity. Moreover, evidence has shown that the impacts of nutrients may depend on additional factors, namely soil conditions and grazing, increasing the uncertainty about the effects of increasing nutrient availability in these systems. In this work, we assessed the short-term effects (1 year) of fertilization in an extensively grazed oak open woodland (called montado, or dehesa), in Spain. Plots comprised a complete randomized design with four treatments: control (not fertilized), fertilization with nitrogen at a rate of 100 kg N ha−1, fertilization with phosphorous (50 kg P ha−1) and fertilization with both N and P (100 kg ha−1 N + 50 kg ha−1 P). We assessed changes in plant species composition and functional diversity and evaluated the association between species and fertilization treatments with an indicator species analysis. Our results showed that species diversity increased with NP fertilization and that forbs in particular increased in cover and richness. SLA and seed mass also showed differences compared to the control. The Community-weighted mean and functional dispersion of groups based on growth form and N-fixing ability were not influenced by fertilization. Two species were significantly associated with fertilized plots: the spiny forb Carlina racemosa and the latex-producing forb Tolpis barbata. Our study suggests that short-term fertilization may alleviate nutrient limitations in these systems, increasing plant diversity, although longer-term studies are needed to understand the effects of a continuous increase in nutrient availability.
期刊介绍:
Agriculture, Ecosystems and Environment publishes scientific articles dealing with the interface between agroecosystems and the natural environment, specifically how agriculture influences the environment and how changes in that environment impact agroecosystems. Preference is given to papers from experimental and observational research at the field, system or landscape level, from studies that enhance our understanding of processes using data-based biophysical modelling, and papers that bridge scientific disciplines and integrate knowledge. All papers should be placed in an international or wide comparative context.