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Zettlemoyer MA, Munck S, Poschlod P, Rosbakh S. Subtle changes in plant diversity in the Bavarian Alps over the past eight decades. Ecol Evol 2024; 14:e70035. [PMID: 39224160 PMCID: PMC11366975 DOI: 10.1002/ece3.70035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2024] [Revised: 07/08/2024] [Accepted: 07/08/2024] [Indexed: 09/04/2024] Open
Abstract
Historical resurveys represent a unique opportunity to analyze vegetation dynamics over longer timescales than is typically achievable. Leveraging the oldest historical dataset of vegetation change in the Bavarian Alps, Germany, we address how environmental conditions, vegetation composition, and functional diversity in the calcareous grasslands of the Schachen region have changed across different elevational ranges over an 83-year timeframe. We document changes in regional average temperature and precipitation. We use indicator values (IV) for species' ecological preferences and their palatability to grazers to infer local conditions (temperature, soil moisture/fertility, and grazing regime). We further estimate changes in temporal beta-diversity and functional trait community composition between historical (1936) and contemporary (2019) surveys in two elevational (subalpine and alpine) belts. Both subalpine and alpine sites became drier; subalpine sites also became warmer with more palatable plants. Species occurrence and abundance in the Schachen region has not changed substantially over time despite changing macroclimate and local environmental conditions under anthropogenic change. Yet these grasslands have experienced several "invisible" changes in functional composition over the past 80 years. As the Schachen has become drier, species with traits related to drought tolerance and animal-based dispersal have increased in dominance. Specifically, in alpine sites, community-weighted means revealed that with low fecundity, higher potential for endo- and epizoochory (seed dispersal via animal gut and fur, respectively), higher foliar frost tolerance, and deeper dormancy increased in dominance. Similar trends were found for increasing dominance of low fecundity, epizoochorous species in subalpine sites. Vegetation data from resurveying historical plots in combination with changes in local conditions, classic biodiversity indices, and functional trait indices can provide more holistic insights into changes in the environment and potential impacts of those environmental changes on long-term plant community and functional diversity.
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Affiliation(s)
| | - Svenja Munck
- Department of Ecology and Conservation BiologyUniversitat RegensburgRegensburgGermany
| | - Peter Poschlod
- Department of Ecology and Conservation BiologyUniversitat RegensburgRegensburgGermany
| | - Sergey Rosbakh
- Department of Ecology and Conservation BiologyUniversitat RegensburgRegensburgGermany
- Department of Plant and Environmental SciencesUniversity of CopenhagenCopenhagenDenmark
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2
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Kovacsics-Vári G, Sonkoly J, Tóth K, McIntosh-Buday A, Díaz Cando PE, Törő-Szijgyártó V, Balogh N, Guallichico Suntaxi LR, Espinoza Ami FD, Matus G, Tóthmérész B, Török P. High species richness of sheep-grazed sand pastures is driven by disturbance-tolerant and weedy short-lived species. Ecol Evol 2024; 14:e70282. [PMID: 39247166 PMCID: PMC11381081 DOI: 10.1002/ece3.70282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 08/22/2024] [Accepted: 08/27/2024] [Indexed: 09/10/2024] Open
Abstract
We selected 15 sheep-grazed sand pastures along a gradient of increasing grazing intensity to study the fine-scale patterns of main biomass fractions (green biomass, litter) and that of plant species and functional groups (life forms and social behaviour types). We classified them into five grazing intensity levels based on stocking density, proximity to drinking and resting places and the number of faeces. We aimed to answer the following questions: (i) How does increasing intensity of sheep grazing affect the amount of green biomass, the species richness and their relationship in sand pastures? (ii) How does increasing intensity of sheep grazing affect the biomass of perennial and short-lived graminoids and forbs? (iii) How does the disturbance value-expressed in the biomass ratio of disturbance-tolerant and ruderal species-change along the gradient of grazing intensity? A unimodal relationship between green biomass and species richness was detected; however, the ordination (canonical correspondence analysis, CCA) showed no clustering of pastures subjected to the same levels of grazing intensity. Along the grazing intensity gradient we found an increasing trend in species richness and significant differences in green biomass (decreasing trend), litter (decreasing trend), graminoids (decreasing trend) and short-lived forbs (increasing trend). We found an increasing amount of disturbance-tolerant and ruderal species with increasing grazing intensity. We suggest that we might need to use multiple scales for sampling and a fine-scale assessment of grazing intensity. Our findings might be instructive for pastures in densely populated regions, which are prone to the encroachment of disturbance-tolerant and ruderal species.
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Affiliation(s)
| | - Judit Sonkoly
- Department of Ecology University of Debrecen Debrecen Hungary
- HUN-REN-UD Functional and Restoration Ecology Research Group Debrecen Hungary
| | - Katalin Tóth
- Department of Ecology University of Debrecen Debrecen Hungary
- HUN-REN-UD Functional and Restoration Ecology Research Group Debrecen Hungary
| | - Andrea McIntosh-Buday
- Department of Ecology University of Debrecen Debrecen Hungary
- HUN-REN-UD Functional and Restoration Ecology Research Group Debrecen Hungary
| | | | - Viktória Törő-Szijgyártó
- Department of Ecology University of Debrecen Debrecen Hungary
- HUN-REN-UD Functional and Restoration Ecology Research Group Debrecen Hungary
| | - Nóra Balogh
- Department of Ecology University of Debrecen Debrecen Hungary
| | | | | | - Gábor Matus
- Department of Botany University of Debrecen Debrecen Hungary
| | - Béla Tóthmérész
- Department of Ecology University of Debrecen Debrecen Hungary
- HUN-REN-UD Biodiversity and Ecosystem Services Research Group Debrecen Hungary
| | - Péter Török
- Department of Ecology University of Debrecen Debrecen Hungary
- HUN-REN-UD Functional and Restoration Ecology Research Group Debrecen Hungary
- Polish Academy of Sciences Botanical Garden-Centre for Biological Diversity Conservation in Powsin Warszawa Poland
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3
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Zhang H, Liu N, Yang G, Badgery W, Guo Y, Zhang Y. Diet selection of sheep shifted from quality to quantity characteristics of forages as sward availability decreased. Animal 2022; 16:100546. [DOI: 10.1016/j.animal.2022.100546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Revised: 04/22/2022] [Accepted: 04/25/2022] [Indexed: 11/29/2022] Open
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Zhang R, Wang Z, Niu S, Tian D, Wu Q, Gao X, Schellenberg MP, Han G. Diversity of plant and soil microbes mediates the response of ecosystem multifunctionality to grazing disturbance. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 776:145730. [PMID: 33639460 DOI: 10.1016/j.scitotenv.2021.145730] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 01/04/2021] [Accepted: 02/04/2021] [Indexed: 05/27/2023]
Abstract
Biodiversity drives ecosystem functioning across grassland ecosystems. However, few studies have examined how grazing intensity affects ecosystem multifunctionality (EMF) via its effects on plant diversity and soil microbial diversity in dry grasslands. We conducted a 12-year experiment manipulating sheep grazing intensity in a desert steppe of northern China. Through measuring plant species diversity, soil microbial diversity (bacteria diversity) and multiple ecosystem functions (i.e., aboveground net primary productivity, belowground biomass of plant community, temporal stability of ANPP, soil organic matter, moisture, available nitrogen and phosphorus, ecosystem respiration and gross ecosystem productivity), we aimed to understand how grazing intensity affected EMF via changing the diversity of plants and microbes. Our results showed that increasing grazing intensity significantly reduced EMF and most individual ecosystem functions, as well as the diversity of plants and microbes, while EMF and most individual functions were positively related to plant diversity and soil microbial diversity under all grazing intensities. In particular, soil microbial diversity in shallow soil layers (0-5 cm depth) had stronger positive correlations with plant diversity and EMF than in deeper soil layers. Furthermore, structural equation modeling (SEM) showed that grazing reduced EMF mainly via reducing plant diversity, rather than by reducing soil microbial diversity. Thus, plant diversity played a more important role in mediating the response of EMF to grazing disturbance. This study highlights the critical role of above- and belowground diversity in mediating the response of EMF to grazing intensity, which has important implications for biodiversity conservation and sustainability in arid grasslands.
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Affiliation(s)
- Ruiyang Zhang
- Key Laboratory of Grassland Resources of the Ministry of Education, Key Laboratory of Forage Cultivation, Processing and High Efficient Utilization of the Ministry of Agriculture and Rural Affairs, Inner Mongolia Key Laboratory of Grassland Management and Utilization, College of Grassland, Resources and Environment, Inner Mongolia Agricultural University, No. 29 Erdos St., Hohhot, Inner Mongolia 010011, China; Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Zhongwu Wang
- Key Laboratory of Grassland Resources of the Ministry of Education, Key Laboratory of Forage Cultivation, Processing and High Efficient Utilization of the Ministry of Agriculture and Rural Affairs, Inner Mongolia Key Laboratory of Grassland Management and Utilization, College of Grassland, Resources and Environment, Inner Mongolia Agricultural University, No. 29 Erdos St., Hohhot, Inner Mongolia 010011, China.
| | - Shuli Niu
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China.
| | - Dashuan Tian
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Qian Wu
- Key Laboratory of Grassland Resources of the Ministry of Education, Key Laboratory of Forage Cultivation, Processing and High Efficient Utilization of the Ministry of Agriculture and Rural Affairs, Inner Mongolia Key Laboratory of Grassland Management and Utilization, College of Grassland, Resources and Environment, Inner Mongolia Agricultural University, No. 29 Erdos St., Hohhot, Inner Mongolia 010011, China
| | - Xuefeng Gao
- College of Life Sciences and Technology, Inner Mongolia Normal University, No. 81 Zhaowuda Road, Saihan District, Hohhot, Inner Mongolia 010020, China
| | - Michael P Schellenberg
- Swift Current Research and Development Centre, Agriculture and Agri-Food Canada, 1 Airport Rd., Box 1030, Swift Current, Saskatchewan S9H 3X2, Canada
| | - Guodong Han
- Key Laboratory of Grassland Resources of the Ministry of Education, Key Laboratory of Forage Cultivation, Processing and High Efficient Utilization of the Ministry of Agriculture and Rural Affairs, Inner Mongolia Key Laboratory of Grassland Management and Utilization, College of Grassland, Resources and Environment, Inner Mongolia Agricultural University, No. 29 Erdos St., Hohhot, Inner Mongolia 010011, China
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Molnár Z, Kelemen A, Kun R, Máté J, Sáfián L, Provenza F, Díaz S, Barani H, Biró M, Máté A, Vadász C. Knowledge co‐production with traditional herders on cattle grazing behaviour for better management of species‐rich grasslands. J Appl Ecol 2020. [DOI: 10.1111/1365-2664.13664] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Zsolt Molnár
- MTA Centre for Ecological Research Institute of Ecology and Botany Vácrátót Hungary
| | - András Kelemen
- MTA Centre for Ecological Research, Institute of Ecology and Botany MTA‐ÖK Lendület Seed Ecology Research Group Vácrátót Hungary
| | - Róbert Kun
- Department of Nature Conservation and Landscape Ecology Szent István University Gödöllő Hungary
| | | | | | - Fred Provenza
- Department of Wildland Resources Utah State University Logan UT USA
| | - Sandra Díaz
- CONICET and National University of Córdoba Córdoba Argentina
| | - Hossein Barani
- Gorgan University of Agricultural Sciences and Natural Resources Gorgan Iran
| | - Marianna Biró
- MTA Centre for Ecological Research GINOP Sustainable Ecosystems Group Tihany Hungary
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6
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Pauler CM, Isselstein J, Suter M, Berard J, Braunbeck T, Schneider MK. Choosy grazers: Influence of plant traits on forage selection by three cattle breeds. Funct Ecol 2020. [DOI: 10.1111/1365-2435.13542] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Caren M. Pauler
- Forage Production and Grassland SystemsAgroscope Zurich Switzerland
- Department of Crop Sciences Georg‐August‐University Goettingen Germany
- Centre for Organismal Studies Ruprecht‐Karls‐University Heidelberg Germany
| | | | - Matthias Suter
- Forage Production and Grassland SystemsAgroscope Zurich Switzerland
| | | | - Thomas Braunbeck
- Centre for Organismal Studies Ruprecht‐Karls‐University Heidelberg Germany
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Kelemen A, Tölgyesi C, Valkó O, Deák B, Miglécz T, Fekete R, Török P, Balogh N, Tóthmérész B. Density-Dependent Plant-Plant Interactions Triggered by Grazing. FRONTIERS IN PLANT SCIENCE 2019; 10:876. [PMID: 31333709 PMCID: PMC6624794 DOI: 10.3389/fpls.2019.00876] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 06/20/2019] [Indexed: 06/10/2023]
Abstract
Plant species performance in rangelands highly depends on the effect of grazing and also on the occurrence of unpalatable benefactor species that can act as biotic refuges protecting neighboring plants from herbivores. The balance between facilitation and competition may changes with the benefactor density. Despite the high number of studies on the role of biotic refuges, the density dependent effects of unpalatable herbaceous plants on the performance of other species, and on the habitat heterogeneity of rangelands are still unclear. Therefore, we performed a study to test the following hypotheses: (i) Performances of understory species follow a humped-back relationship along the density gradient of the unpalatable benefactor species. (ii) Small-scale heterogeneity of the vegetation decreases with increasing benefactor density. We studied meadow steppes with medium intensity cattle grazing in Hungary. We surveyed understory species' performance (number of flowering shoots and cover scores) along the density gradient of a common, native unpalatable species (Althaea officinalis). Our findings supported both hypotheses. We found unimodal relationship between the benefactor cover and both the flowering success and richness of understory species. Moreover, small-scale heterogeneity declined with increasing benefactor cover. In this study we detected a humped-back pattern of facilitation along the density gradient of an herbaceous benefactor in pastures. Indeed, this pattern was predictable based on such conceptual models like "consumer pressure-abiotic stress model," "humped-back model," "intermediate disturbance hypothesis," and "disturbance heterogeneity model"; but until now the validity of these relationships has not been demonstrated for herbaceous species. By the demonstration of this effect between herbaceous species we can better forecast the responses of grasslands to changes in management.
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Affiliation(s)
- András Kelemen
- MTA’s Post Doctoral Research Program, MTA TKI, Budapest, Hungary
- Department of Ecology, University of Debrecen, Debrecen, Hungary
| | - Csaba Tölgyesi
- Department of Ecology, Faculty of Science and Technology, University of Szeged, Szeged, Hungary
| | - Orsolya Valkó
- MTA-DE Lendület Seed Ecology Research Group, Debrecen, Hungary
| | - Balázs Deák
- MTA-DE Biodiversity and Ecosystem Services Research Group, Debrecen, Hungary
| | - Tamás Miglécz
- Department of Ecology, University of Debrecen, Debrecen, Hungary
| | - Réka Fekete
- Department of Botany, University of Debrecen, Debrecen, Hungary
| | - Péter Török
- MTA-DE Lendület Functional and Restoration Ecology Research Group, Debrecen, Hungary
| | - Nóra Balogh
- Juhász Nagy Pál Doctorate School, University of Debrecen, Debrecen, Hungary
| | - Béla Tóthmérész
- Department of Ecology, University of Debrecen, Debrecen, Hungary
- MTA-DE Biodiversity and Ecosystem Services Research Group, Debrecen, Hungary
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8
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Török P, Penksza K, Tóth E, Kelemen A, Sonkoly J, Tóthmérész B. Vegetation type and grazing intensity jointly shape grazing effects on grassland biodiversity. Ecol Evol 2018; 8:10326-10335. [PMID: 30397469 PMCID: PMC6206222 DOI: 10.1002/ece3.4508] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 06/14/2018] [Accepted: 08/09/2018] [Indexed: 11/22/2022] Open
Abstract
In the Palaearctic steppe zone, overgrazing was identified as one of the key drivers of declining grassland biodiversity, which underlines the necessity of the functional evaluation of increased grazing pressure on grassland vegetation. We tested the following hypotheses: (a) The effect of grazing intensity on species and functional diversity is strongly dependent on grassland type. (b) The magnitude of diet selectivity of grazers decreases with increasing grazing intensity. (c) Increasing grazing intensity increases evenness and functional evenness of the subjected grasslands. We analyzed vegetation patterns in four types of grasslands (Dry alkali short-grass steppes, Dry loess steppes, Non-alkali wet and Alkali wet grasslands) along an intensity gradient of beef cattle grazing at 73 sites in Hungary. Species richness, Shannon diversity, evenness, and four leaf traits were analyzed. We calculated community-weighted means for each single trait, and multi-trait functional richness, functional evenness, and divergence for all leaf traits. All species and functional diversity metrics were significantly affected by the grassland type, except leaf dry matter content. The effect of interaction between grazing intensity and grassland type was also significant for functional richness, functional evenness, community-weighted means of leaf area, and for species richness and evenness. An upward trend of specific leaf area was detected in all grasslands with the highest scores for the overgrazed sites, but the change was also grassland type dependent. The detected trend suggests that with increased intensity the overall selectivity of grazing decreased. We found that evenness was affected but functional evenness was not affected by grazing intensity. Functional evenness scores were more related to the grassland type than to changes in grazing intensity, and displayed a high variability. We stress that one-size-fits-all strategies cannot be recommended and actions should be fine-tuned at least at the level of grassland type.
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Affiliation(s)
- Péter Török
- MTA‐DE Lendület Functional and Restoration Ecology Research GroupDebrecenHungary
- Department of EcologyUniversity of DebrecenDebrecenHungary
| | - Károly Penksza
- Department of BotanyInstitute of Botany and EcophysiologySzent István UniversityGödöllőHungary
| | - Edina Tóth
- MTA‐DE Lendület Functional and Restoration Ecology Research GroupDebrecenHungary
| | - András Kelemen
- Department of EcologyUniversity of DebrecenDebrecenHungary
- MTA TKIMTA's Post Doctoral Research ProgramBudapestHungary
| | - Judit Sonkoly
- MTA‐DE Lendület Functional and Restoration Ecology Research GroupDebrecenHungary
- Department of EcologyUniversity of DebrecenDebrecenHungary
| | - Béla Tóthmérész
- Department of EcologyUniversity of DebrecenDebrecenHungary
- MTA‐DE Biodiversity and Ecosystem Services Research GroupDebrecenHungary
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Bumb I, Garnier E, Bastianelli D, Richarte J, Bonnal L, Kazakou E. Influence of management regime and harvest date on the forage quality of rangelands plants: the importance of dry matter content. AOB PLANTS 2016; 8:plw045. [PMID: 27339049 PMCID: PMC4972474 DOI: 10.1093/aobpla/plw045] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Accepted: 05/11/2016] [Indexed: 05/18/2023]
Abstract
In spite of their recognized ecological value, relatively little is known about the nutritional value of species-rich rangelands for herbivores. We investigated the sources of variation in dry matter digestibility (DMD), neutral detergent fibre content (NDF) and nitrogen concentration (NC) in plants from species-rich Mediterranean rangelands in southern France, and tested whether the dry matter content (DMC) was a good predictor of the forage quality of different plant parts. Sixteen plant species with contrasting growth forms (rosette, tussock, extensive and stemmed-herb) were studied, representative of two management regimes imposed in these rangelands: (i) fertilization and intensive grazing and (ii) non-fertilization and moderate grazing. Among the 16 plant species, four species were found in both treatments, allowing us to assess the intraspecific variability in forage quality and DMC across the treatments. The components of nutritional value (DMD, NDF and NC) as well as the DMC of leaves, stems and reproductive plant parts, were assessed at the beginning of the growing season and at peak standing biomass. All components of nutritional value and DMC were affected by species growth form: rosettes had higher DMD and NC than tussocks; the reverse being found for NDF and DMC. As the season progressed, DMD and NC of the different plant parts decreased while NDF and DMC increased for all species. DMC was negatively related to DMD and NC and positively to NDF, regardless of the source of variation (species, harvest date, management regime or plant part). Path analysis indicated that NDF was the main determinant of DMD. Better assessment of forage quality in species-rich systems requires consideration of their growth form composition. DMC of all plant parts, which is closely related to NDF, emerged as a good predictor and easily measured trait to estimate DMD in these species-rich systems.
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Affiliation(s)
- Iris Bumb
- Montpellier Supagro, Centre d'Ecologie Fonctionnelle et Evolutive (UMR CEFE), CNRS - Université de Montpellier - Université Paul-Valéry Montpellier - EPHE, Campus CNRS, 1919 Route de Mende, 34293 Montpellier Cedex 5, France
| | - Eric Garnier
- Centre d'Ecologie Fonctionnelle et Evolutive (UMR CEFE), CNRS - Université de Montpellier - Université Paul-Valéry Montpellier - EPHE, Campus CNRS, 1919 Route De Mende, 34293 Montpellier Cedex 5, France
| | | | - Jean Richarte
- Montpellier Supagro, Centre d'Ecologie Fonctionnelle et Evolutive (UMR CEFE), CNRS - Université de Montpellier - Université Paul-Valéry Montpellier - EPHE, Campus CNRS, 1919 Route de Mende, 34293 Montpellier Cedex 5, France
| | - Laurent Bonnal
- CIRAD, UMR SELMET, Baillarguet, 34398 Montpellier Cedex 5, France
| | - Elena Kazakou
- Montpellier Supagro, Centre d'Ecologie Fonctionnelle et Evolutive (UMR CEFE), CNRS - Université de Montpellier - Université Paul-Valéry Montpellier - EPHE, Campus CNRS, 1919 Route de Mende, 34293 Montpellier Cedex 5, France
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Bremm C, Carvalho PCF, Fonseca L, Amaral GA, Mezzalira JC, Perez NB, Nabinger C, Laca EA. Diet Switching by Mammalian Herbivores in Response to Exotic Grass Invasion. PLoS One 2016; 11:e0150167. [PMID: 26919613 PMCID: PMC4769132 DOI: 10.1371/journal.pone.0150167] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Accepted: 02/10/2016] [Indexed: 11/19/2022] Open
Abstract
Invasion by exotic grasses is a severe threat to the integrity of grassland ecosystems all over the world. Because grasslands are typically grazed by livestock and wildlife, the invasion is a community process modulated by herbivory. We hypothesized that the invasion of native South American grasslands by Eragrostis plana Nees, an exotic tussock-forming grass from Africa, could be deterred by grazing if grazers switched dietary preferences and included the invasive grass as a large proportion of their diets. Bos taurus (heifers) and Ovis aries (ewes) grazed plots with varying degrees of invasion by E. plana in a replicated manipulative experiment. Animal positions and species grazed were observed every minute in 45-min grazing session. Proportion of bites and steps in and out of E. plana tussocks were measured and used to calculate several indices of selectivity. Both heifers and ewes exhibited increasing probability of grazing E. plana as the proportion of area covered by tussocks increased, but they behaved differently. In agreement with expectations based on the allometry of dietary preferences and morphology, ewes consumed a low proportion of E. plana, except in areas that had more than 90% E. plana cover. Heifers consumed proportionally more E. plana than ewes. Contrary to our hypothesis, herbivores did not exhibit dietary switching towards the invasive grass. Moreover, they exhibited avoidance of the invasive grass and preference for short-statured native species, both of which should tend to enhance invasion. Unless invasive plants are highly palatable to livestock, the effect of grazing to deter the invasion is limited, due to the inherent avoidance of the invasive grass by the main grazers in the ecosystem, particularly sheep.
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Affiliation(s)
- Carolina Bremm
- Grazing Ecology Research Group, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Paulo C. F. Carvalho
- Grazing Ecology Research Group, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Lidiane Fonseca
- Grazing Ecology Research Group, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Glaucia A. Amaral
- Grazing Ecology Research Group, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Jean C. Mezzalira
- Grazing Ecology Research Group, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | | | - Carlos Nabinger
- Grazing Ecology Research Group, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Emilio A. Laca
- Department of Plant Sciences, University of California Davis, Davis, California, United States of America
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Effects of livestock exclusion and climate change on aboveground biomass accumulation in alpine pastures across the Northern Tibetan Plateau. ACTA ACUST UNITED AC 2014. [DOI: 10.1007/s11434-014-0362-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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