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Gomaa NH, Hegazy AK, Alhaithloul HAS. Facilitation by Haloxylon persicum Shrubs Enhances Density and Richness of Soil Seed Bank of Annual Plants in a Hyper-Arid Ecosystem. PLANTS (BASEL, SWITZERLAND) 2023; 12:1276. [PMID: 36986963 PMCID: PMC10056119 DOI: 10.3390/plants12061276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 03/08/2023] [Accepted: 03/09/2023] [Indexed: 06/19/2023]
Abstract
The soil seed bank is an essential functional component of plant communities. In arid ecosystems, the island-like distribution of shrubs influences the spatial distribution of the soil seed bank. Very little is known about seed banks in deserts of the Middle East. The present study aimed to evaluate the facilitative effects of Haloxylon persicum shrubs on the soil seed bank of annual plants in a sandy desert region in northwestern Saudi Arabia during two consecutive growing seasons (2017-2018 and 2018-2019) with contrasting rainfall. A total of 480 soil samples at 12 stands were collected from two microhabitats, under shrubs and in open areas, soon after the two growing seasons. The germinable seed bank of annual plants was estimated by controlled seedling emergence method. Shrubs significantly facilitated the accumulation of seed bank beneath their canopies after the two growing seasons. In both microhabitats, the size and species richness of soil seed bank were significantly greater after the wet growing season (2018-2019) than following the dry season (2017-2018). The facilitative effects of shrubs were greater following the moister growing season than after the dry season. The effect of shrubs on seed bank-annual vegetation similarity varied between growing seasons, being greater in shrub interspaces than beneath shrub canopies for the dry growing season, while during the wet season, the similarity of the seed bank with standing annual vegetation was greater in sub-canopy microhabitat than in bare soil.
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Affiliation(s)
- Nasr H. Gomaa
- Department of Botany and Microbiology, Faculty of Science, Beni-Suef University, Beni-Suef 62521, Egypt
| | - Ahmad K. Hegazy
- Department of Botany and Microbiology, Faculty of Science, Cairo University, Giza 12613, Egypt
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Cui G, Pugnaire FI, Yang L, Zhao W, Ale R, Shen W, Luo T, Liang E, Zhang L. Shrub-mediated effects on soil nitrogen determines shrub-herbaceous interactions in drylands of the Tibetan Plateau. FRONTIERS IN PLANT SCIENCE 2023; 14:1137365. [PMID: 36844071 PMCID: PMC9950575 DOI: 10.3389/fpls.2023.1137365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Accepted: 01/30/2023] [Indexed: 06/18/2023]
Abstract
INTRODUCTION Shrub promotes the survival, growth and reproduction of understory species by buffering the environmental extremes and improving limited resources (i.e., facilitation effect) in arid and semiarid regions. However, the importance of soil water and nutrient availability on shrub facilitation, and its trend along a drought gradient have been relatively less addressed in water-limited systems. METHODS We investigated species richness, plant size, soil total nitrogen and dominant grass leaf δ13C within and outside the dominant leguminous cushion-like shrub Caragana versicolor along a water deficit gradient in drylands of Tibetan Plateau. RESULTS We found that C. versicolor increased grass species richness but had a negative effect on annual and perennial forbs. Along the water deficit gradient, plant interaction assessed by species richness (RIIspecies) showed a unimodal pattern with shift from increase to decrease, while plant interaction assessed by plant size (RIIsize) did not vary significantly. The effect of C. versicolor on soil nitrogen, rather than water availability, determined its overall effect on understory species richness. Neither the effect of C. versicolor on soil nitrogen nor water availability affected plant size. DISCUSSION Our study suggests that the drying tendency in association with the recent warming trends observed in drylands of Tibetan Plateau, will likely hinder the facilitation effect of nurse leguminous shrub on understories if moisture availability crosses a critical minimum threshold.
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Affiliation(s)
- Guangshuai Cui
- State Key Laboratory of Tibetan Plateau Earth System Science, Resources and Environment (TPESRE), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, China
- Estación Experimental de Zonas Áridas, Consejo Superior de Investigaciones Científicas, Almería, Spain
| | - Francisco I. Pugnaire
- Estación Experimental de Zonas Áridas, Consejo Superior de Investigaciones Científicas, Almería, Spain
| | - Liu Yang
- State Key Laboratory of Tibetan Plateau Earth System Science, Resources and Environment (TPESRE), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Wanglin Zhao
- State Key Laboratory of Tibetan Plateau Earth System Science, Resources and Environment (TPESRE), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, China
| | - Rita Ale
- State Key Laboratory of Tibetan Plateau Earth System Science, Resources and Environment (TPESRE), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, China
| | - Wei Shen
- State Key Laboratory of Tibetan Plateau Earth System Science, Resources and Environment (TPESRE), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, China
| | - Tianxiang Luo
- State Key Laboratory of Tibetan Plateau Earth System Science, Resources and Environment (TPESRE), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, China
| | - Eryuan Liang
- State Key Laboratory of Tibetan Plateau Earth System Science, Resources and Environment (TPESRE), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, China
| | - Lin Zhang
- State Key Laboratory of Tibetan Plateau Earth System Science, Resources and Environment (TPESRE), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, China
- Institute of Science and Technology Information of Tibet Autonomous Region, Lhasa, China
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Morcillo L, Bautista S. Interacting water, nutrients, and shrub age control steppe grass‐on‐shrub competition: Implications for restoration. Ecosphere 2022. [DOI: 10.1002/ecs2.4093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
- Luna Morcillo
- Mediterranean Center for Environmental Studies (CEAM Foundation), Joint Research Unit University of Alicante‐CEAM University of Alicante Alicante Spain
| | - Susana Bautista
- Department of Ecology and IMEM University of Alicante Alicante Spain
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Gefei Z, Zhao W, Xiaofen W. The importance of facilitation on community assembly disappears under severe drought stress. Funct Ecol 2022. [DOI: 10.1111/1365-2435.14043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Zhang Gefei
- Linze Inland River Basin Research Station Northwest Institute of Eco‐Environment and Resources Chinese Academy of Sciences CN‐730000 Lanzhou China
| | - Wenzhi Zhao
- Linze Inland River Basin Research Station Northwest Institute of Eco‐Environment and Resources Chinese Academy of Sciences CN‐730000 Lanzhou China
| | - Wang Xiaofen
- Prata cultural College Gansu Agricultural University CN‐730000 Lanzhou China
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Gomaa NH, Hegazy AK, Latef AAHA. Facilitation Effects of Haloxylon salicornicum Shrubs on Associated Understory Annuals, and a Modified “Stress-Gradient” Hypothesis for Droughty Times. PLANTS 2020; 9:plants9121726. [PMID: 33297465 PMCID: PMC7762360 DOI: 10.3390/plants9121726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 12/01/2020] [Accepted: 12/04/2020] [Indexed: 11/28/2022]
Abstract
Perennial shrub-annual plant interactions play key roles in desert regions influencing the structure and dynamics of plant communities there. In the present study, carried out in northwestern Saudi Arabia, we examined the effect of Haloxylon salicornicum shrubs on their associated understory annual species across four consecutive growing seasons, along with a record of the seasonal rainfall patterns. We measured density and species richness of all the annual species in permanent quadrats located beneath individual shrubs, as well as in the spaces between shrubs. During wet growing season H. salicornicum shrubs significantly enhanced the density and species richness of sub-canopy species, whereas in the relatively dry seasons they exerted negative effects on the associated species. In all growing seasons, the presence of shrubs was associated with enhanced soil properties, including increased organic carbon content, silt + clay, and levels of nutrients (N, P and K). Shrubs improved soil moisture content beneath their canopies in the wet growing season, while in the dry seasons they had negative effects on water availability. Differences in effects of H. salicornicum on understory plants between growing seasons seem due to the temporal changes in the impact of shrubs on water availability. Our results suggest the facilitative effects of shrubs on sub-canopy annuals in arid ecosystems may switch to negative effects with increasing drought stress. We discuss the study in light of recent refinements of the well-known “stress-gradient hypothesis”.
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Affiliation(s)
- Nasr H. Gomaa
- Department of Botany and Microbiology, Faculty of Science, Beni-Suef University, Beni-Suef 62521, Egypt
- Biology Department, College of Science, Jouf University, P.O. Box 2014, Sakaka 72341, Saudi Arabia
- Correspondence:
| | - Ahmad K. Hegazy
- Department of Botany and Microbiology, Faculty of Science, Cairo University, Giza 12613, Egypt;
| | - Arafat Abdel Hamed Abdel Latef
- Department of Biology, Turabah University College, Turabah Branch, Taif University, P.O. Box 11099, Taif 21944, Saudi Arabia;
- Botany and Microbiology Department, Faculty of Science, South Valley University, Qena 83523, Egypt
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Chaieb G, Wang X, Abdelly C, Michalet R. Shift from short‐term competition to facilitation with drought stress is due to a decrease in long‐term facilitation. OIKOS 2020. [DOI: 10.1111/oik.07528] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Ghassen Chaieb
- Faculty of Sciences of Bizerte, Univ. of Carthage Zarzouna Tunisia
- Univ. of Bordeaux, UMR CNRS 5805 EPOC, Allée Geoffroy Saint‐Hilaire – CS 50023 FR‐33615 Pessac France
| | - Xiangtai Wang
- State Key Laboratory of Grassland and Agro‐ecosystems, School of Life Sciences, Lanzhou Univ., Lanzhou Gansu PR China
| | - Chedly Abdelly
- Laboratory of Extremophiles Plants, Center of Biotechnology of Borj Cedria, 2050 Tunisia
| | - Richard Michalet
- Univ. of Bordeaux, UMR CNRS 5805 EPOC, Allée Geoffroy Saint‐Hilaire – CS 50023 FR‐33615 Pessac France
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Chaieb G, Abdelly C, Michalet R. A Regional Assessment of Changes in Plant–Plant Interactions Along Topography Gradients in Tunisian Sebkhas. Ecosystems 2020. [DOI: 10.1007/s10021-020-00567-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Uyà M, Bulleri F, Wright JT, Gribben PE. Facilitation of an invader by a native habitat-former increases along interacting gradients of environmental stress. Ecology 2019; 101:e02961. [PMID: 31863455 DOI: 10.1002/ecy.2961] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 09/23/2019] [Accepted: 11/11/2019] [Indexed: 01/09/2023]
Abstract
Native habitat-forming species can facilitate invasion by reducing environmental stress or consumer pressure. However, the intensity of one stressor along a local gradient may differ when expanding the scale of observation to encompass major variations in background environmental conditions. In this study, we determined how facilitation of the invasive porcelain crab, Petrolisthes elongatus, by the native tube-forming serpulid, Galeolaria caespitosa, varied with environmental gradients at local (tidal height) and larger (wave exposure) spatial scales. G. caespitosa constructs a complex calcareous matrix on the underside of intertidal boulders and we predicted that its positive effects on P. elongatus density would increase in intensity with shore height and be stronger at wave-sheltered than wave-exposed locations. To test these predictions, we conducted two experiments. First, we determined the effects of serpulid presence (boulders with live or dead serpulid matrix vs. bare boulders) at six shore heights that covered the intertidal distribution of P. elongatus. Second, we determined the effects of serpulid presence (present vs. absent), shore height (high vs. low) and wave exposure (sheltered vs. exposed) on crabs across six locations within the invaded range in northern Tasmania, Australia. In Experiment 1, the presence of serpulids (either dead or alive) enhanced P. elongatus densities at all shore heights, with facilitation intensity (as determined by a relative interaction index; RII) tending to increase with shore height. In Experiment 2, serpulids facilitated P. elongatus across shore heights and wave exposures, although crab densities were lower at high shore levels of wave-sheltered locations. However, the intensity of crab facilitation by serpulids was greater on wave-sheltered than on wave-exposed shores, but only at the high shore level. This study demonstrates that local effects of native habitat-formers on invasive species are dependent on prevailing environmental conditions at larger spatial scales and that, under more stressful conditions, invaders become increasingly reliant on positive interactions with native habitat-formers. Increased strength of local-scale facilitation by native species, dampening broader scale variations in environmental stressors, could enhance the ability of invasive species to establish self-sustaining populations in the invaded range.
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Affiliation(s)
- Marc Uyà
- Dipartimento di Biologia, Università di Pisa, Via Derna 1, 56126, Pisa, Italy.,Centre for Marine Science and Innovation, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, 2052, New South Wales, Australia
| | - Fabio Bulleri
- Dipartimento di Biologia, Università di Pisa, Via Derna 1, 56126, Pisa, Italy.,CoNISMa, Consorzio Nazionale Interuniversitario per le Scienze del Mare, Piazzale Flaminio 9, 00196, Roma, Italy
| | - Jeffrey T Wright
- Institute for Marine and Antarctic Studies, University of Tasmania, Private Bag 129, Hobart, 7001, Australia
| | - Paul E Gribben
- Centre for Marine Science and Innovation, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, 2052, New South Wales, Australia.,Sydney Institute of Marine Science, 19 Chowder Bay Road, Mosman, 2088, New South Wales, Australia
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Swanson EK, Sheley RL, James JJ. Do shrubs improve reproductive chances of neighbors across soil types in drought? Oecologia 2019; 192:79-90. [PMID: 31768737 DOI: 10.1007/s00442-019-04559-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Accepted: 11/11/2019] [Indexed: 11/28/2022]
Abstract
Plant reproduction is highly sensitive to stress from severe weather. While facilitation has been shown to buffer negative impacts along stress gradients, less is known about facilitating plant reproduction in drought periods. Because intensity and frequency of drought are predicted to increase, plant reproductive facilitation has important implications for a species ability to adapt to changes in climate. Our primary study objective is to test if nurse shrubs act as reproductive micro-refugia across soil types, by improving reproductive potential of perennial bunchgrass neighbors subjected to severe drought. To investigate this objective, we designed a fully factored study testing direct interaction between shrub and bunchgrasses in eastern Oregon sagebrush steppe, at two sites with different soil types. The study consisted of six simple effect treatments combining three moisture regimes (moist, ambient, and drought) with two shrub conditions (shrub intact or shrub removed). Our results indicate when facilitation of reproductive potential occurs, it occurs strongly and particularly in drought, consistent with the stress gradient hypothesis (SGH), where several species produced at least 54% more inflorescences in the presence of shrub neighbors. In addition, we found facilitation to be consistent with the SGH at the species level likely reflecting differences in plant strategy and perception of strain, but to follow alternative SGH models more closely at the site level where facilitation declined on the drier soil. Ultimately, our findings highlight the importance of facilitation in improving plant reproductive potential in drought, and support the role of nurse shrubs as micro-refugia in a changing climate.
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Affiliation(s)
- Elizabeth K Swanson
- Department of Forest Ecosystems and Society, Oregon State University, Corvallis, OR, 97331, USA.
| | - Roger L Sheley
- United States Department of Agriculture-Agricultural Research Service, Burns, OR, 97720, USA
| | - Jeremy J James
- Division of Agriculture and Natural Resources, Sierra Foothills Research and Extension Center, University of California, Browns Valley, CA, 95918, USA
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Quon LH, Bobich EG, Questad EJ. Facilitation and herbivory during restoration of California coastal sage scrub. Restor Ecol 2019. [DOI: 10.1111/rec.12966] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Lauren H. Quon
- Biological Sciences Department, College of ScienceCalifornia State Polytechnic University Pomona, 3801 W Temple Avenue Pomona CA 91786 U.S.A
| | - Edward G. Bobich
- Biological Sciences Department, College of ScienceCalifornia State Polytechnic University Pomona, 3801 W Temple Avenue Pomona CA 91786 U.S.A
| | - Erin J. Questad
- Biological Sciences Department, College of ScienceCalifornia State Polytechnic University Pomona, 3801 W Temple Avenue Pomona CA 91786 U.S.A
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Gonzalez SL, Ghermandi L. Dwarf shrub facilitates seedling recruitment and plant diversity in semiarid grasslands. PLoS One 2019; 14:e0212058. [PMID: 30730964 PMCID: PMC6366867 DOI: 10.1371/journal.pone.0212058] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Accepted: 01/26/2019] [Indexed: 11/19/2022] Open
Abstract
The facilitation mechanism maintains ecosystem richness by increasing seedling recruitment. Overgrazed grasslands of northwestern Patagonia are invaded by shrubs that could promote the seedling recruitment of forage species. We investigated the role of Acaena splendens shrubs on the maintenance of diversity and its usefulness as a nurse shrub in the recruitment of Festuca pallescens, a grass of high forage value present with a low cover in degraded grasslands. To test the performance of A.splendens as a nurse plant in non-degraded grassland, we recorded the species richness four years inside of A. splendens senescent shrubs and in gaps among dominant tussock grasses. Species were grouped in four functional groups: annual and biannual herbs and grasses, perennial herbs, perennial grasses and shrubs. To test the usefulness of A. splendens in the restoration of degraded grassland, we monitored the seedling emergence and survival of F. pallescens inside A. splendens and in gaps. We related seedling survival to meteorological and microenvironmental conditions. Species richness was higher in Acaena nurse plants than in gaps. The frequency of functional groups, with exception of annual and biannual herbs and grasses, were higher in Acaena than in gaps. Seedling emergence and survival of F. pallescens were higher in Acaena, but the seedlings died in summer in both microsites. Mean maximum temperature was higher and mean minimum humidity lower in gaps than in Acaena during spring. However, the spring-summer season in which we monitored F. pallescens survival, was exceptionally dry and hot, affecting the survival of F. pallescens seedlings. Our results show that A. splendens act as a nurse species increasing the richness in the non-degraded grassland and facilitating the seedling recruitment of an important forage species in the degraded grassland. Nevertheless, the facilitation mechanism will fail in drought conditions, indicating that this restoration tool is limited by climate.
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Affiliation(s)
- Sofía L. Gonzalez
- Laboratorio Ecotono, INIBIOMA, Universidad Nacional del Comahue, CONICET, Bariloche, Río Negro, Argentina
- * E-mail:
| | - Luciana Ghermandi
- Laboratorio Ecotono, INIBIOMA, Universidad Nacional del Comahue, CONICET, Bariloche, Río Negro, Argentina
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