1
|
Canepuccia AD, Hidalgo FJ, Fanjul E, Iribarne OO. Reciprocal facilitation between ants and small mammals in tidal marshes. Oecologia 2024; 204:575-588. [PMID: 38376632 DOI: 10.1007/s00442-024-05513-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 01/17/2024] [Indexed: 02/21/2024]
Abstract
The role of facilitation in shaping natural communities has primarily been studied in the context of plant assemblages, while its relevance for mobile animals remains less understood. Our study investigates whether reciprocal interspecific facilitation may exist between fire ants (Solenopsis richteri) and cavies (Cavia aperea), two mobile animals, in the SW Atlantic coast brackish marshes. Field samples showed a spatial association between ant mounds and cavies, and that ants prefer to use cavy runways for movement within the marsh. Through experiments involving transplanting the dominant plant, cordgrass (Spartina densiflora), and manipulating cavy presence in areas with and without ant mounds, we observed that cavies forage extensively (and defecate more) near ant mounds. The ants actively remove cavy droppings in their mound vicinity. These ant activities and interactions with cavy droppings led to reduced moisture and organic content while increasing nitrate and phosphate levels in marsh sediment. Consequently, this enhanced plant growth, indirectly facilitating the cavies, which preferred consuming vegetation near ant mounds. These cascading indirect effects persisted over time; even four months after cavies left the marshes, transplanted plants near ant mounds remained larger and exhibited more leaf senescence when exposed to cavy herbivory. Therefore, the networks of positive interactions appear to generate simultaneous selection among species (populations), promoting coexistence within the community. Although complex, these reciprocal facilitative effects among mobile animals may be more common than currently believed and should be further studied to gain a better understanding of the underlying mechanisms driving species coexistence in natural communities.
Collapse
Affiliation(s)
- Alejandro D Canepuccia
- Laboratorio de Ecología, Instituto de Investigaciones Marinas y Costeras (IIMyC), Universidad Nacional de Mar del Plata (UNMdP) - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Funes 3250, 7600, Mar del Plata, Argentina.
| | - Fernando J Hidalgo
- Grupo Humedales y Ambientes Costeros, Instituto de Investigaciones Marinas y Costeras (IIMyC), Universidad Nacional de Mar del Plata (UNMdP) - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Funes 3250, 7600, Mar del Plata, Argentina
| | - Eugenia Fanjul
- Laboratorio de Ecología, Instituto de Investigaciones Marinas y Costeras (IIMyC), Universidad Nacional de Mar del Plata (UNMdP) - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Funes 3250, 7600, Mar del Plata, Argentina
| | - Oscar O Iribarne
- Laboratorio de Ecología, Instituto de Investigaciones Marinas y Costeras (IIMyC), Universidad Nacional de Mar del Plata (UNMdP) - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Funes 3250, 7600, Mar del Plata, Argentina
| |
Collapse
|
2
|
Ale R, Zhang L, Bahadur Raskoti B, Cui G, Pugnaire FI, Luo T. Leaf carbon isotope tracks the facilitation pattern of legume shrubs shaped by water availability and species replacement along a large elevation gradient in Trans-Himalayas. ANNALS OF BOTANY 2023; 132:429-442. [PMID: 37632795 PMCID: PMC10667008 DOI: 10.1093/aob/mcad117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 08/24/2023] [Indexed: 08/28/2023]
Abstract
BACKGROUND AND AIMS Understanding patterns and mechanisms of nurse plant facilitation is important to predict the resilience of arid/semi-arid ecosystems to climate change. We investigate whether water availability and nurse species turnover interact to shape the facilitation pattern of widespread legume shrubs along a large elevation gradient. We also investigate whether leaf δ13C of nurse plants can track the facilitation pattern. METHODS We measured the relative interaction index (RII) of the number of species within and outside the canopy of two widespread legume shrub species (Caragana gerardiana and Caragana versicolor) alternatively distributed along a large elevation gradient in the Trans-Himalayas. We also assessed the proportional increase of species richness (ISR) at the community level using the paired plot data. To determine site-specific water availability, we measured the leaf δ13C of nurse shrubs and calculated the Thornthwaite moisture index (MI) for each elevation site. KEY RESULTS Elevational variations in RII, ISR and δ13C were mainly explained by the MI when the effects of soil nitrogen and plant traits (leaf nitrogen and shrub size) were controlled. Variations in RII and ISR across the two nurse species were explained better by δ13C than by smoothly changing climatic factors along elevation. At the transition zone between the upper limit of C. gerardiana (4100 m) and the lower limit of C. versicolor (4200 m), RII and ISR were much higher in C. versicolor than in C. gerardiana under a similar MI. Such an abrupt increase in facilitation induced by nurse species replacement was well tracked by the variation of δ13C. CONCLUSIONS Water availability and nurse species replacement are crucial to shaping facilitation patterns by legume shrubs along a large elevation gradient in dry mountainous regions, such as the Trans-Himalayas. Turnover in nurse species under global change might significantly alter the pattern of nurse plant facilitation associated with water availability, which can be well tracked by leaf δ13C.
Collapse
Affiliation(s)
- Rita Ale
- Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100101, China
| | - Lin Zhang
- Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100101, China
| | | | - Guangshuai Cui
- Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100101, China
| | - Francisco I Pugnaire
- Estación Experimental de Zonas Áridas, Consejo Superior de Investigaciones Científicas, Almería, Spain
| | - Tianxiang Luo
- Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100101, China
| |
Collapse
|
3
|
Fernández G, Rodríguez C. Antagonistic effects of grazers and shrubs on the emergence and establishment of seedlings in a sub-humid grassland of South America. Oecologia 2023; 203:219-229. [PMID: 37839062 DOI: 10.1007/s00442-023-05464-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Accepted: 10/01/2023] [Indexed: 10/17/2023]
Abstract
Biotic interactions are key processes that strongly affect the performance of seedlings in plant communities. In this work, we evaluated the effect of grazing and shrubs on the emergence and establishment of seedlings with different life-forms (dicotyledonous and monocotyledonous) in a sub-humid grassland community. We delimited five areas of 25 m2 in which we established four permanent plots of 1.0 m2. Two plots were centered at shrubs (beneath the canopy) and two in open spaces (without shrubs). Half of the shrubs and open plots were fenced to avoid grazing. During two consecutive years we marked all emerged seedlings and followed their fate. Grazing promoted dicotyledonous seedling emergence but reduced establishment. On the contrary, shrubs reduced dicotyledonous emergence but enhanced establishment. We did not detect any effect of shrubs or grazing on the emergence of monocotyledonous seedlings. Most seedlings emerged during fall and winter and died during spring and summer. Recruitment from seeds in this grassland is rare and complex, involving biotic and abiotic factors, with different responses to grazing and shrubs depending on seedling life-form and ontogeny.
Collapse
Affiliation(s)
- Gastón Fernández
- Departamento de Sistemas Agrarios y Paisajes Culturales, Centro Universitario Regional del Este, Universidad de la República, Ruta 8 km 282, 33000, Treinta y Tres, Uruguay.
| | - Claudia Rodríguez
- Instituto de Ecología y Ciencias Ambientales, Facultad de Ciencias, Universidad de la República, Iguá 4225, 11400, Montevideo, Uruguay
| |
Collapse
|
4
|
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.
Collapse
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
| |
Collapse
|
5
|
Consumer pressure and supplemental pollination mediate shrub facilitation of a native annual desert plant. Oecologia 2023; 201:489-498. [PMID: 36607452 DOI: 10.1007/s00442-022-05309-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 12/26/2022] [Indexed: 01/07/2023]
Abstract
Shrubs are important factors in the assembly of desert plant and animal communities. By providing shelter and resources to other plants and animals, shrubs can change plant-animal interactions including those with consumers and pollinators. Here, we test the hypothesis that shrubs facilitate the reproduction of other desert plants by influencing pollination and compensation for consumer pressure. We used the known benefactor Larrea tridentata as our focal shrub species and the flowering annual Malacothrix glabrata as a potential protege in the Mojave Desert. We tested the effects of facilitation (shrub microsite), consumer pressure (both artificial folivory and florivory), and pollination (ambient or supplemented) on flower and seed production of the annual M. glabrata. We found that floral production and seed mass were similar between microsites but that pollen was limited under shrubs in the absence of any other manipulation. Plants under shrubs produced more flowers and seeds than in the open when folivory and florivory treatments were applied. Malacothrix glabrata experienced a cost to association with L. tridentata in terms of pollen limitation but plants were better able to compensate for consumer pressure under shrubs through increased flower and seed production when damaged. Therefore, association with shrubs involves a reproductive trade-off between costs to pollination and benefits to compensation for consumer pressure.
Collapse
|
6
|
Yin D, Meiners SJ, Ni M, Ye Q, He F, Cadotte MW. Positive interactions of native species melt invasional meltdown over
long‐term
plant succession. Ecol Lett 2022; 25:2584-2596. [DOI: 10.1111/ele.14127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 08/24/2022] [Accepted: 08/30/2022] [Indexed: 11/28/2022]
Affiliation(s)
- Deyi Yin
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden Chinese Academy of Sciences Guangzhou China
- South China National Botanical Garden Guangzhou China
| | - Scott J. Meiners
- Department of Biological Sciences Eastern Illinois University Charleston Illinois USA
| | - Ming Ni
- Département de Biologie Université de Sherbrooke Sherbrooke Quebec Canada
| | - Qing Ye
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden Chinese Academy of Sciences Guangzhou China
- South China National Botanical Garden Guangzhou China
| | - Fangliang He
- Department of Renewable Resources University of Alberta Edmonton Alberta Canada
- ECNU‐Alberta Joint Lab for Biodiversity Study, Tiantong Forest Ecosystem National Observation and Research Station, School of Ecology and Environmental Sciences East China Normal University Shanghai China
| | - Marc W. Cadotte
- Department of Biological Sciences University of Toronto‐Scarborough Toronto Ontario Canada
- Ecology and Evolutionary Biology University of Toronto Toronto Ontario Canada
| |
Collapse
|
7
|
Lorusso NS, Faillace CA. Indirect facilitation between prey promotes asymmetric apparent competition. J Anim Ecol 2022; 91:1869-1879. [PMID: 35765925 PMCID: PMC9544837 DOI: 10.1111/1365-2656.13768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 06/17/2022] [Indexed: 11/30/2022]
Abstract
Apparent competition is one mechanism that can contribute to the complex dynamics observed in natural systems, yet it remains understudied in empirical systems. Understanding the dynamics that shape the outcome of processes like apparent competition is vital for appreciating how they influence natural systems. We empirically evaluated the role of indirect trophic interactions in driving apparent competition in a model laboratory system. Our experimental system was designed to let us evaluate combined direct and indirect interactions among species. Here we describe the results of a factorial experiment using two noncompeting prey (Colpidium kleini, a heterotroph, and Chlamydomonas reinhardtii, an autotroph) consumed by a generalist predator Euplotes eurystomus to explore the dynamics of apparent competition. To gain intuition into the potential mechanism driving the asymmetry in the observed results, we further explored the system using structural equation modelling. Our results show an important role of positive interactions and indirect effects contributing to apparent competition in this system with a marked asymmetrical outcome favouring one prey, Chlamydomonas. The selected structural equation supports a role of indirect facilitation; although Chlamydomonas (a photoautotroph) and Colpidium (a bacterivore) use different resources and therefor do not directly compete, Colpidium reduces bacteria that may compete with Chlamydomonas. In addition, formation of colonies by Chlamydomonas in response to predation by Euplotes provides an antipredator defence not available to Colpidium. Asymmetric apparent competition may be more common in natural systems than the symmetric interaction originally proposed in classic theory, suggesting that exploration of the mechanisms driving the asymmetry of the interaction can be a fruitful area of further research to better our understanding of interspecific interactions and community dynamics.
Collapse
Affiliation(s)
- Nicholas S Lorusso
- Department of Ecology, Evolution, and Natural Resources, Rutgers University, Jersey.,Current Institution: Department of Life Sciences, University of North Texas at Dallas, 7500 University Hills Blvd, Dallas, Texas, USA
| | - Cara A Faillace
- Department of Ecology, Evolution, and Natural Resources, Rutgers University, Jersey.,Current Institution: University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| |
Collapse
|
8
|
Yang F, Zhang J, Cisse EHM, Li DD, Guo LY, Xiang LS, Miao LF. Competitive Relationship Between Cleistocalyx operculatus and Syzygium jambos Under Well-Watered Conditions Transforms Into a Mutualistic Relationship Under Waterlogging Stress. FRONTIERS IN PLANT SCIENCE 2022; 13:869418. [PMID: 35755663 PMCID: PMC9231832 DOI: 10.3389/fpls.2022.869418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 05/19/2022] [Indexed: 06/15/2023]
Abstract
Competition and abiotic stress such as waterlogging (WL) represent main factors limiting plant growth and determining plant resistance and distribution patterns in wetland ecosystems. One of the basic steps for wetland restoration is to plant trees to ensure a quicker recovery and prevent erosion. Plant survival and adaptation are considered criteria of principal priority for the screening of plant species for wetland ecosystem restoration. WL influences plant species in wetlands via the deterioration of the plant root environment which leads to oxygen deficiency that affects plant growth, photosynthesis, respiration, and other metabolic processes. A suitable plant species was determined according to tolerance to WL during wetland vegetation recovery activities. Thus, two tree species (Cleistocalyx operculatus and Syzygium jambos) that showed a certain waterlogging tolerance were chosen to study their behaviors in different planting model and environmental conditions. Given that interspecific relationship should be considered during plant community construction, the eco-physiological adaptable mechanisms between these woody plants under well-watered condition and waterlogging stress were explored. Results showed that both species were waterlogging-tolerant species due to their ability to adapt to submergence conditions for 120 days. Moreover, C. operculatus possessed stronger tolerance to waterlogging stress because of a significant adventitious roots biomass accumulation. A competitive relationship was found between C. operculatus and S. jambos under well-watered condition, and C. operculatus showed better growth performance benefited from morphological responses (plant height, number of blade and leaf area) and endogenous hormone variations. In comparison, S. jambos suffered some negative effects when the well-watered mixed planting was used. However, the competitive relationship under well-watered condition was transformed into mutualistic relationship under waterlogging stress. The mixed planting under waterlogging condition significantly improved the tolerance of C. operculatus and S. jambos to waterlogging stress, compared with the monoculture., Especially, S. jambos showed improvements in root length, root surface area, and redox equilibration between lower levels of relative conductivity, malondialdehyde, and O 2 ⋅ - and had increased levels of non-enzymatic antioxidant components, such as reduced glutathione and soluble proteins. The interspecific relationship between C. operculatus and S. jambos was altered by waterlogging stress, and both showed improved tolerance to waterlogging stress. This study can provide a glimmer of light on suitable plant species selection and plant community construction during the revegetation activities in wetland zones. C. operculatus and S. jambos represent potential candidates in wetland restoration in a mixed planting model.
Collapse
Affiliation(s)
- Fan Yang
- School of Ecological and Environmental Sciences, Hainan University, Haikou, China
- Key Laboratory of Agro-Forestry Environmental Processes and Ecological Regulation of Hainan Province, Center for Eco-Environmental Restoration Engineering of Hainan Province, Haikou, China
| | - Juan Zhang
- School of Ecological and Environmental Sciences, Hainan University, Haikou, China
- Key Laboratory of Agro-Forestry Environmental Processes and Ecological Regulation of Hainan Province, Center for Eco-Environmental Restoration Engineering of Hainan Province, Haikou, China
| | - El-Hadji Malick Cisse
- School of Ecological and Environmental Sciences, Hainan University, Haikou, China
- School of Life Science, Hainan University, Haikou, China
| | - Da-Dong Li
- School of Ecological and Environmental Sciences, Hainan University, Haikou, China
- Key Laboratory of Agro-Forestry Environmental Processes and Ecological Regulation of Hainan Province, Center for Eco-Environmental Restoration Engineering of Hainan Province, Haikou, China
| | - Lu-Yao Guo
- School of Ecological and Environmental Sciences, Hainan University, Haikou, China
- Key Laboratory of Agro-Forestry Environmental Processes and Ecological Regulation of Hainan Province, Center for Eco-Environmental Restoration Engineering of Hainan Province, Haikou, China
| | - Li-Shan Xiang
- School of Ecological and Environmental Sciences, Hainan University, Haikou, China
| | - Ling-Feng Miao
- School of Ecological and Environmental Sciences, Hainan University, Haikou, China
- School of Plant Protection, Hainan University, Haikou, China
| |
Collapse
|
9
|
Species-specific facilitation shapes primary successional communities under nurse trees in an abandoned slag dump. Urban Ecosyst 2022. [DOI: 10.1007/s11252-022-01237-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
10
|
Lucero JE, Faist AM, Lortie CJ, Callaway RM. Risk of Facilitated Invasion Depends Upon Invader Identity, Not Environmental Severity, Along an Aridity Gradient. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.886690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Positive interactions can drive the assembly of desert plant communities, but we know little about the species-specificity of positive associations between native shrubs and invasive annual species along aridity gradients. These measures are essential for explaining, predicting, and managing community-level responses to plant invasions and environmental change. Here, we measured the intensity of spatial associations among native shrubs and the annual plant community—including multiple invasive species and their native neighbors—along an aridity gradient across the Mojave and San Joaquin Deserts, United States. Along the gradient, we sampled the abundance and species richness of invasive and native annual species using 180 pairs of shrub and open microsites. Across the gradient, the invasive annuals Bromus madritensis ssp. rubens (B. rubens), B. tectorum, B. diandrus, Hordeum murinum, and Brassica tournefortii were consistently more abundant under shrubs than away from shrubs, suggesting positive effects of shrubs on these species. In contrast, abundance of the invasive annual Schismus spp. was greater away from shrubs than under shrubs, suggesting negative effects of shrubs on this species. Similarly, native annual abundance (pooled) and native species richness were greater away from shrubs than under shrubs. Shrub-annual associations were not influenced by shrub size or aridity. Interestingly, we found correlative evidence that B. rubens reduced native abundance (pooled), native species richness, and exotic abundance (pooled) under, but not away from shrubs. We conclude that native shrubs have considerable potential to directly (by increasing invader abundance) and indirectly (by increasing negative impacts of invaders on neighbors) facilitate plant invasions along broad environmental gradients, but these effects may depend more upon invader identity than environmental severity.
Collapse
|
11
|
Wu S, Wen L, Dong S, Gao X, Xu Y, Li S, Dong Q, Wessell K. The Plant Interspecific Association in the Revegetated Alpine Grasslands Determines the Productivity Stability of Plant Community Across Restoration Time on Qinghai-Tibetan Plateau. FRONTIERS IN PLANT SCIENCE 2022; 13:850854. [PMID: 35386668 PMCID: PMC8978524 DOI: 10.3389/fpls.2022.850854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/08/2022] [Accepted: 02/22/2022] [Indexed: 06/14/2023]
Abstract
Grassland cultivation is the key measure for restoring "Black Beach," the extremely degraded alpine meadow in the Three River Headwater Area of the Qinghai-Tibetan Plateau. In this study, we examined the inter-specific relationship in the vegetation community of cultivated grasslands with different restoration times through the network analysis method. The results showed that with the extension of restoration time, the development of cultivated grassland would lead to increasing neutral interactions among the plant species. The proportion of species with positive and negative associations in the community decreased, while the number of species-independent pairs increased significantly. The complexity of plant interspecific association (species network density) had more influence on community stability with the extension of recovery time, which can be used to quantify the characteristics of community structure.
Collapse
Affiliation(s)
- Shengnan Wu
- School of Grassland Science, Beijing Forestry University, Beijing, China
| | - Lu Wen
- Ministry of Education Key Laboratory of Ecology and Resource Use of the Mongolian Plateau and Inner Mongolia Key Laboratory of Grassland Ecology, School of Ecology and Environment, Inner Mongolia University, Hohhot, China
| | - Shikui Dong
- School of Grassland Science, Beijing Forestry University, Beijing, China
| | - Xiaoxia Gao
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
| | - Yudan Xu
- College of Grassland Science, Shanxi Agricultural University, Jinzhong, China
| | - Shuai Li
- College of Resources and Environment, Shanxi Agricultural University, Jinzhong, China
| | - Quanming Dong
- Qinghai Academy of Animal and Veterinary Sciences, Qinghai University, Xining, China
| | - Kelly Wessell
- Tompkins Cortland Community College, Dryden, NY, United States
| |
Collapse
|
12
|
Castillioni K, Patten MA, Souza L. Precipitation effects on grassland plant performance are lessened by hay harvest. Sci Rep 2022; 12:3282. [PMID: 35228587 PMCID: PMC8885915 DOI: 10.1038/s41598-022-06961-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 12/24/2021] [Indexed: 11/09/2022] Open
Abstract
Climate and human management, such as hay harvest, shape grasslands. With both disturbances co-occurring, understanding how these ecosystems respond to these combined drivers may aid in projecting future changes in grasslands. We used an experimental precipitation gradient combined with mimicked acute hay harvest (clipping once a year) to examine (1) whether hay harvest influences precipitation effects on plant performance (cover and height) and (2) the role of inter-specific responses in influencing plant performance. We found that hay harvest reduced the strength of precipitation effects on plant performance through changes in bare-ground soil cover. Species performance were mainly influenced by change in abiotic factors, often responding negatively, as hay harvest increased bare-ground amount. Conversely, altered precipitation without hay harvest promoted plant species performance through abiotic factors change first, followed by biotic. Most species, including the dominant grass Schizachyrium scoparium, increased their performance with greater leaf area index (proxy for canopy structure). Our experiment demonstrates that plant performance responds directly to abiotic factors with hay harvest, but indirectly without hay harvest. Positive effects of increasing precipitation were likely due to microhabitat amelioration and resource acquisition, thus inclusion of hay harvest as a disturbance lessens positive impacts of biotic variables on species performance to climate change.
Collapse
|
13
|
Loy X, Brosi BJ. The effects of pollinator diversity on pollination function. Ecology 2022; 103:e3631. [PMID: 35050504 DOI: 10.1002/ecy.3631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 10/15/2021] [Accepted: 10/28/2021] [Indexed: 11/08/2022]
Abstract
Pollination is a key ecological function of most terrestrial ecosystems. Decades of research on single-trophic-level communities, particularly plant communities, have helped build the foundation of diversity-function theory. Yet as it stands, this theory appears to be less useful for inter-trophic-level functions such as pollination, as evidenced by empirical findings that are often inconsistent with theoretical expectations. In this review, we evaluate how canonical diversity-function theory has been applied to pollination function, focusing on empirical studies of the mechanisms that drive pollinator diversity-function relationships. We first identify key features of pollination function that have hampered reconciliation with current theory. We then examine terminology for mechanisms used to discuss the findings from pollinator diversity-function studies that are sometimes inconsistent with established ecological concepts. We propose a revised diversity-function framework and describe two non-canonical diversity-function mechanisms that are particularly applicable to pollination. The first, 'interactive functional complementarity', was identified previously but remains overlooked. The second, a new diversity-function mechanism, 'functional enhancement', occurs when pollinator diversity increases within-niche activity. Finally, we discuss experimental approaches necessary to detect diversity-function effects in pollination. This article is protected by copyright. All rights reserved.
Collapse
Affiliation(s)
- Xingwen Loy
- Conservation & Research Department, Atlanta Botanical Garden, Atlanta, GA
| | - Berry J Brosi
- Department of Biology, University of Washington, Seattle, WA
| |
Collapse
|
14
|
Morais RFD, Macedo MTDS, Gomes MTD, Fernades IM, Morais FFD, Marcusso GM, Sousa Júnior JRD. Influence of palm trees on the richness and distribution of plant species on the murundus at a Caatinga/Cerrado ecotone. RODRIGUÉSIA 2022. [DOI: 10.1590/2175-7860202273049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Abstract Understand the role of the drivers in vegetation pattern is essential in ecology since diversity plays a major role in the stability and maintenance of plant communities. The murundus are small and scattered earthmounds with a differentiated flora of its surrounding. In our study site (Campo Maior, Piauí, Northeastern Brazil), we classified them in three categories: presence of carnaúba (PC), presence of tucum (PT), and with the absence of palm trees (AP). Here, our goals were (1) to explore alpha diversity using the richness estimator and abundance distribution rank, expecting that palm trees could influence the richness of plant species on murundus; (2) analyzing the species richness-area relationship in the murundus, following the assumptions that the largest one holds more species; (3) find the changes in the species composition (beta diversity) between the three categories of murundus, assuming which the presence of palm trees influence the species composition; and (4) investigate if the distance between murundus is a decisive factor in the species composition, where the closest murundus are the most similar in species composition. Ours results showed that palms trees do not influence the richness of the murundus, the largest murundus are the richest ones, and the turnover predominantly determines beta diversity in the different murundus categories. Furthermore, the distance between the murundus did not determine its floristic similarity. Overall, we demonstrated which the species of palm trees are not the main drive of the plant assemblage in the murundus, however its size comprises a major factor in the richness, with great species substitution, which explains the high plant diversity.
Collapse
|
15
|
Lucero JE, Callaway RM, Faist AM, Lortie CJ. An unfortunate alliance: Native shrubs increase the abundance, performance, and apparent impacts of Bromus tectorum across a regional aridity gradient. Basic Appl Ecol 2021. [DOI: 10.1016/j.baae.2021.09.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
|
16
|
Spatial pattern and association of shrub species in gravel hilly and rocky low mountain desert dominated by relict Helianthemum songaricum in China. Glob Ecol Conserv 2021. [DOI: 10.1016/j.gecco.2021.e01914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
|
17
|
Schlau B, Huxman T, Mooney K, Pratt J. Facilitation at early growth stages results in spatial associations and stable coexistence in late growth stages of two long‐lived, dominant shrubs. OIKOS 2021. [DOI: 10.1111/oik.08603] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Benjamin Schlau
- W. M. Keck Science Dept, Claremont McKenna College, Pitzer College and Scripps College Claremont CA USA
| | - Travis Huxman
- UC Irvine, Dept of Ecology and Evolutionary Biology Irvine CA USA
| | - Kailen Mooney
- UC Irvine, Dept of Ecology and Evolutionary Biology Irvine CA USA
| | - Jessica Pratt
- UC Irvine, Dept of Ecology and Evolutionary Biology Irvine CA USA
| |
Collapse
|
18
|
|
19
|
Hesse E, O'Brien S, Luján AM, Sanders D, Bayer F, van Veen EM, Hodgson DJ, Buckling A. Stress causes interspecific facilitation within a compost community. Ecol Lett 2021; 24:2169-2177. [PMID: 34259374 DOI: 10.1111/ele.13847] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 05/10/2021] [Accepted: 06/21/2021] [Indexed: 01/10/2023]
Abstract
Ecological theory predicts interactions between species to become more positive under abiotic stress, while competition should prevail in more benign environments. However, experimental tests of this stress gradient hypothesis in natural microbial communities are lacking. We test this hypothesis by measuring interactions between 10 different members of a bacterial community inhabiting potting compost in the presence or absence of toxic copper stress. We found that copper stress caused significant net changes in species interaction signs, shifting the net balance towards more positive interactions. This pattern was at least in part driven by copper-sensitive isolates - that produced relatively small amounts of metal-detoxifying siderophores - benefitting from the presence of other species that produce extracellular detoxifying agents. As well as providing support for the stress gradient hypothesis, our results highlight the importance of community-wide public goods in shaping microbial community composition.
Collapse
Affiliation(s)
- Elze Hesse
- CEC & ESI, Biosciences, University of Exeter, Penryn Campus, Cornwall, UK
| | - Siobhan O'Brien
- CEC & ESI, Biosciences, University of Exeter, Penryn Campus, Cornwall, UK.,Institute of Integrative Biology, University of Liverpool, Liverpool, UK
| | - Adela M Luján
- CEC & ESI, Biosciences, University of Exeter, Penryn Campus, Cornwall, UK.,CIQUIBIC, Departamento de Química Biológica, Facultad de Ciencias Químicas, CONICET, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Dirk Sanders
- CEC & ESI, Biosciences, University of Exeter, Penryn Campus, Cornwall, UK
| | - Florian Bayer
- CEC & ESI, Biosciences, University of Exeter, Penryn Campus, Cornwall, UK
| | - Eleanor M van Veen
- Camborne School of Mines, CEMPS, University of Exeter, Penryn Campus, Cornwall, UK
| | - Dave J Hodgson
- CEC, Biosciences, University of Exeter, Penryn Campus, Cornwall, UK
| | - Angus Buckling
- CEC & ESI, Biosciences, University of Exeter, Penryn Campus, Cornwall, UK
| |
Collapse
|
20
|
Soil arthropods indicate the range of plant facilitation on the soil of Mediterranean drylands. THEOR ECOL-NETH 2021. [DOI: 10.1007/s12080-020-00498-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
|
21
|
Aros-Mualin D, Noben S, Karger DN, Carvajal-Hernández CI, Salazar L, Hernández-Rojas A, Kluge J, Sundue MA, Lehnert M, Quandt D, Kessler M. Functional Diversity in Ferns Is Driven by Species Richness Rather Than by Environmental Constraints. FRONTIERS IN PLANT SCIENCE 2021; 11:615723. [PMID: 33505416 PMCID: PMC7829179 DOI: 10.3389/fpls.2020.615723] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 12/07/2020] [Indexed: 06/12/2023]
Abstract
Functional traits determine how species interact with their abiotic and biotic environment. In turn, functional diversity describes how assemblages of species as a whole are adapted to their environment, which also determines how they might react to changing conditions. To fully understand functional diversity, it is fundamental to (a) disentangle the influences of environmental filtering and species richness from each other, (b) assess if the trait space saturates at high levels of species richness, and (c) understand how changes in species numbers affect the relative importance of the trait niche expansion and packing. In the present study, we determined functional diversity of fern assemblages by describing morphological traits related to resource acquisition along four tropical elevational transects with different environmental conditions and species richness. We used several functional diversity indices and their standardized effect size to consider different aspects of functional diversity. We contrasted these aspects of functional diversity with climate data and species richness using linear models and linear mixed models. Our results show that functional morphological trait diversity was primarily driven by species richness and only marginally by environmental conditions. Moreover, increasing species richness contributed progressively to packing of the morphological niche space, while at the same time decreasing morphological expansion until a saturation point was reached. Overall, our findings suggest that the density of co-occurring species is the fundamental driving force of morphological niche structure, and environmental conditions have only an indirect influence on fern resource acquisition strategies.
Collapse
Affiliation(s)
- Daniela Aros-Mualin
- Department of Systematic and Evolutionary Botany, University of Zurich, Zurich, Switzerland
| | - Sarah Noben
- Department of Systematic and Evolutionary Botany, University of Zurich, Zurich, Switzerland
| | - Dirk N. Karger
- Swiss Federal Research Institute WSL, Birmensdorf, Switzerland
| | | | - Laura Salazar
- Centro de Investigación de la Biodiversidad y Cambio Climático (BioCamb) e Ingeniería en Biodiversidad y Recursos Genéticos, Facultad de Ciencias de Medio Ambiente, Universidad Tecnológica Indoamérica, Quito, Ecuador
| | | | - Jürgen Kluge
- Department of Geography, Philipps University Marburg, Marburg, Germany
| | - Michael A. Sundue
- The Pringle Herbarium, Department of Plant Biology, University of Vermont, Burlington, VT, United States
| | - Marcus Lehnert
- Department of Geobotany and Botanical Garden, Herbarium, Martin-Luther-Universität Halle-Wittenberg, Halle, Germany
| | - Dietmar Quandt
- Nees-Institute for Biodiversity of Plants, University of Bonn, Bonn, Germany
| | - Michael Kessler
- Department of Systematic and Evolutionary Botany, University of Zurich, Zurich, Switzerland
| |
Collapse
|
22
|
Jones HH, Robinson SK. Vegetation structure drives mixed-species flock interaction strength and nuclear species roles. Behav Ecol 2020. [DOI: 10.1093/beheco/araa103] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Mixed-species flocks are a key facilitative interaction for tropical birds. Forest fragmentation leads to species loss and spatial turnover in these flocks, yet it is unknown how these changes to composition influence within-flock species interactions. We used network analysis to characterize flocking interactions along a fragment-size gradient in the Colombian Western Andes. We asked 1) how patch size, edge density, and vegetation structure explained network measures indicative of flock cohesion, 2) whether changes were driven by flocking species turnover or changes to the frequency of species co-occurrence, and 3) whether nuclear species, those that maintain flock stability and cohesion, changed in importance across the gradient. We constructed weighted social networks from flock compositions observed on 500-m transects, and then calculated global network measures and the centrality of six nuclear species. Patch size and edge density did not correlate with interspecific co-occurrence patterns, but interaction strength increased with canopy height. Flocks contained numerous, weak interactions, and there were no flock subtypes, suggesting flock composition was dynamic and unstructured. Several redundant nuclear species were present and varied in importance based on ecological conditions. A chlorospingus (Passerellidae) was most central in old-growth forest, whereas several tanager (Thraupidae) species became more central in smaller fragments and disturbed forest. When partitioning network dissimilarity, we found that 66% of dissimilarity resulted from species turnover, whereas only 34% resulted from changes to species co-occurrence. This finding suggests that coherence of flocking behavior itself is maintained even as extensive species turnover occurs from continuous forest to small fragments.
Collapse
Affiliation(s)
- Harrison H Jones
- Department of Biology, University of Florida, Gainesville, FL, USA
- Florida Museum of Natural History, University of Florida, Gainesville, FL, USA
| | - Scott K Robinson
- Department of Biology, University of Florida, Gainesville, FL, USA
- Florida Museum of Natural History, University of Florida, Gainesville, FL, USA
| |
Collapse
|
23
|
Cock MC, Hierro JL. Plant interactions balance under biotic and abiotic stressors: the importance of herbivory in semi-arid ecosystems. Oecologia 2020; 194:685-694. [PMID: 33094382 DOI: 10.1007/s00442-020-04789-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 10/10/2020] [Indexed: 11/28/2022]
Abstract
Biotic and abiotic stressors commonly co-occur in plant communities and influence interactions between plants. However, their combined effects on plant interactions have not been widely studied and are still unclear. Here, we assessed the balance of interactions between neighboring plants along a grazing gradient and under two water regimes. We conducted a three-year-field experiment in semi-arid central Argentina with transplants of the dominant palatable grass Piptochaetium napostaense growing in Baccharis ulicina and open microsites across a gradient of grazing pressure. Additionally, we established a water addition treatment along that gradient. We recorded herbivory, size, and fecundity of P. napostaense. During the first two years, P. napostaense was consumed less and was larger below Baccharis than in the open. These differences were greatest under high grazing pressure. Differences in fecundity between microsites were only detected under high and medium grazing pressure in the first two years. In the third year, Baccharis lost their leaves for unclear reasons and provided poor herbivory protection; hence, P. napostaense plants in Baccharis were larger than those in the open only under medium and low grazing pressure, and there were no differences in fecundity between microsites under any grazing condition. Water additions exerted no effect on plant interactions. The balance of interactions changed from positive under heavy grazing to neutral at low and no grazing and water availability did not alter that balance. We conclude that herbivore pressure is an important driver of the balance of plant interactions in semi-arid environments.
Collapse
Affiliation(s)
- Marina C Cock
- Laboratorio de Ecología, Biogeografía y Evolución Vegetal (LEByEV), Instituto de Ciencias de la Tierra y Ambientales de La Pampa (INCITAP), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)-Universidad Nacional de La Pampa (UNLPam), Mendoza 109, 6300, Santa Rosa, La Pampa, Argentina. .,Departamento de Biología, Facultad de Ciencias Exactas y Naturales, UNLPam, Uruguay 151, 6300, Santa Rosa, La Pampa, Argentina.
| | - José L Hierro
- Laboratorio de Ecología, Biogeografía y Evolución Vegetal (LEByEV), Instituto de Ciencias de la Tierra y Ambientales de La Pampa (INCITAP), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)-Universidad Nacional de La Pampa (UNLPam), Mendoza 109, 6300, Santa Rosa, La Pampa, Argentina.,Departamento de Biología, Facultad de Ciencias Exactas y Naturales, UNLPam, Uruguay 151, 6300, Santa Rosa, La Pampa, Argentina
| |
Collapse
|
24
|
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
| |
Collapse
|
25
|
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]
|
26
|
van der Merwe S, Greve M, Olivier B, le Roux PC. Testing the role of functional trait expression in plant–plant facilitation. Funct Ecol 2020. [DOI: 10.1111/1365-2435.13681] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
| | - Michelle Greve
- Department of Plant and Soil Sciences University of Pretoria Pretoria South Africa
| | - Bernard Olivier
- Department of Plant and Soil Sciences University of Pretoria Pretoria South Africa
| | - Peter C. le Roux
- Department of Plant and Soil Sciences University of Pretoria Pretoria South Africa
| |
Collapse
|
27
|
Abd-ElGawad AM, Rashad YM, Abdel-Azeem AM, Al-Barati SA, Assaeed AM, Mowafy AM. Calligonum polygonoides L. Shrubs Provide Species-Specific Facilitation for the Understory Plants in Coastal Ecosystem. BIOLOGY 2020; 9:biology9080232. [PMID: 32824473 PMCID: PMC7464817 DOI: 10.3390/biology9080232] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Revised: 08/12/2020] [Accepted: 08/13/2020] [Indexed: 11/28/2022]
Abstract
Plant facilitation has a pivotal role in regulating species coexistence, particularly under arid environments. The present study aimed to evaluate the facilitative effect of Calligonum polygonoides L. on its understory plants in coastal habitat. Forty Calligonum shrubs were investigated and the environmental data (soil temperature, moisture, pH, salinity, carbon and nitrogen content, and light intensity), vegetation composition, and diversity of associated species were recorded under- and outside canopies. Eight of the most frequent understory species were selected for evaluating their response to the facilitative effect of C. polygonoides. Bioactive ingredients of Calligonum roots were analyzed using gas chromatography-mass spectrometry (GC-MS), and mycorrhizal biodiversity in their rhizosphere soil was also assessed. The effect of Calligonum on understory plants ranged between facilitation and inhibition in an age-dependent manner. Old shrubs facilitated 18 and inhibited 18 associated species, while young shrubs facilitated 13 and inhibited 9 species. Calligonum ameliorated solar radiation and high-temperature stresses for the under canopy plants. Moreover, soil moisture was increased by 509.52% and 85.71%, while salinity was reduced by 47.62% and 23.81% under old and young shrubs, respectively. Soil contents of C and N were increased under canopy. This change in the microenvironment led to photosynthetic pigments induction in the majority of understory species. However, anthocyanin, proline contents, and antioxidant enzyme activities were reduced in plants under canopy. Thirteen mycorrhizal fungal species were identified in the rhizospheric soil of Calligonum with the predominance of Funneliformis mosseae. Thirty-one compounds were identified in Calligonum root extract in which pyrogallol and palmitic acid, which have antimicrobial and allelopathic activities, were the major components. The obtained results demonstrated that facilitation provided by Calligonum is mediated with multiple mechanisms and included a set of interrelated scenarios that took place in a species-specific manner.
Collapse
Affiliation(s)
- Ahmed M. Abd-ElGawad
- Plant Production Department, College of Food & Agriculture Sciences, King Saud University, P.O. Box 2460, Riyadh 11451, Saudi Arabia;
- Department of Botany, Faculty of Science, Mansoura University, Mansoura 35516, Egypt;
- Correspondence: ; Tel.: +966-562680864
| | - Younes M. Rashad
- Plant Protection and Biomolecular Diagnosis Department, Arid Lands Cultivation Research Institute, City of Scientific Research and Technological Applications (SRTA-City), New Borg El-Arab City 21934, Egypt;
| | - Ahmed M. Abdel-Azeem
- Department of Botany, Faculty of Science, Suez Canal University, Ismailia 41522, Egypt;
| | - Sami A. Al-Barati
- Biology Department, Faculty of Science, Sana’a University, Sana’a 15542, Yemen;
| | - Abdulaziz M. Assaeed
- Plant Production Department, College of Food & Agriculture Sciences, King Saud University, P.O. Box 2460, Riyadh 11451, Saudi Arabia;
| | - Amr M. Mowafy
- Department of Botany, Faculty of Science, Mansoura University, Mansoura 35516, Egypt;
| |
Collapse
|
28
|
Lucero JE, Seifan M, Callaway RM, Lortie CJ. Positive associations with native shrubs are intense and important for an exotic invader but not the native annual community across an aridity gradient. DIVERS DISTRIB 2020. [DOI: 10.1111/ddi.13111] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Affiliation(s)
- Jacob E. Lucero
- Department of Biology York University Toronto Ontario Canada
| | - Merav Seifan
- Mitrani Department of Desert Ecology Swiss Institute for Dryland Environmental and Energy Research The Jacob Blaustein Institutes for Desert Research Ben‐Gurion University of the Negev Midreshet Ben‐Gurion Israel
| | - Ragan M. Callaway
- Division of Biological Sciences and the Institute on Ecosystems University of Montana Missoula MT USA
| | | |
Collapse
|
29
|
Successional trajectory of bacterial communities in soil are shaped by plant-driven changes during secondary succession. Sci Rep 2020; 10:9864. [PMID: 32555419 PMCID: PMC7299987 DOI: 10.1038/s41598-020-66638-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Accepted: 04/27/2020] [Indexed: 11/08/2022] Open
Abstract
This study investigated the potential role of a nitrogen-fixing early-coloniser Alnus Nepalensis D. Don (alder) in driving the changes in soil bacterial communities during secondary succession. We found that bacterial diversity was positively associated with alder growth during course of ecosystem development. Alder development elicited multiple changes in bacterial community composition and ecological networks. For example, the initial dominance of actinobacteria within bacterial community transitioned to the dominance of proteobacteria with stand development. Ecological networks approximating species associations tend to stabilize with alder growth. Janthinobacterium lividum, Candidatus Xiphinematobacter and Rhodoplanes were indicator species of different growth stages of alder. While the growth stages of alder has a major independent contribution to the bacterial diversity, its influence on the community composition was explained conjointly by the changes in soil properties with alder. Alder growth increased trace mineral element concentrations in the soil and explained 63% of variance in the Shannon-diversity. We also found positive association of alder with late-successional Quercus leucotrichophora (Oak). Together, the changes in soil bacterial community shaped by early-coloniser alder and its positive association with late-successional oak suggests a crucial role played by alder in ecosystem recovery of degraded habitats.
Collapse
|
30
|
Bachelot B, Alonso-Rodríguez AM, Aldrich-Wolfe L, Cavaleri MA, Reed SC, Wood TE. Altered climate leads to positive density-dependent feedbacks in a tropical wet forest. GLOBAL CHANGE BIOLOGY 2020; 26:3417-3428. [PMID: 32196863 DOI: 10.1111/gcb.15087] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 02/02/2020] [Indexed: 05/12/2023]
Abstract
Climate change is predicted to result in warmer and drier Neotropical forests relative to current conditions. Negative density-dependent feedbacks, mediated by natural enemies, are key to maintaining the high diversity of tree species found in the tropics, yet we have little understanding of how projected changes in climate are likely to affect these critical controls. Over 3 years, we evaluated the effects of a natural drought and in situ experimental warming on density-dependent feedbacks on seedling demography in a wet tropical forest in Puerto Rico. In the +4°C warming treatment, we found that seedling survival increased with increasing density of the same species (conspecific). These positive density-dependent feedbacks were not associated with a decrease in aboveground natural enemy pressure. If positive density-dependent feedbacks are not transient, the diversity of tropical wet forests, which may rely on negative density dependence to drive diversity, could decline in a future warmer, drier world.
Collapse
Affiliation(s)
| | - Aura M Alonso-Rodríguez
- USDA Forest Service International Institute of Tropical Forestry, Jardín Botánico Sur, Río Piedras, Puerto Rico
| | - Laura Aldrich-Wolfe
- Department of Biological Sciences, North Dakota State University, Fargo, ND, USA
| | - Molly A Cavaleri
- School of Forest Resources and Environmental Science, Michigan Technological University, Houghton, MI, USA
| | - Sasha C Reed
- Southwest Biological Science Center, US Geological Survey, Moab, UT, USA
| | - Tana E Wood
- USDA Forest Service International Institute of Tropical Forestry, Jardín Botánico Sur, Río Piedras, Puerto Rico
| |
Collapse
|
31
|
Bai Y, She W, Zhang Y, Qiao Y, Fu J, Qin S. N enrichment, increased precipitation, and the effect of shrubs collectively shape the plant community in a desert ecosystem in northern China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 716:135379. [PMID: 31839302 DOI: 10.1016/j.scitotenv.2019.135379] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 11/02/2019] [Accepted: 11/02/2019] [Indexed: 06/10/2023]
Abstract
Understanding the responses of biological communities to global climate change is pivotal to accurately forecasting future dynamics and developing effective strategies for the adaptive ecological management of desert ecosystems. Although direct demographic responses of plant species to climatic factors have been widely acknowledged, they are also regulated by interspecific interactions (i.e., the effects of shrubs on herbaceous plants). The magnitude and direction of regulation of such interspecific interactions remain unclear. To address this knowledge gap, a full factorial field experiment simulating three levels of N enrichment (ambient, 10 kg N ha-1 yr-1, and 60 kg N ha-1 yr-1) and three levels of precipitation (ambient, 20% increase, and 40% increase) were conducted in the Mu Us Desert, northern China. N enrichment and increased precipitation significantly increased herbaceous productivity by improving the soil water content and nutrient availability (e.g., soil DIN:SAP) when shrubs were not present. Taller species responded to N enrichment, whereas those with a greater specific leaf area responded to increased precipitation. When shrubs were present, they acted as a 'buffer islands' that moderated the responses of herbaceous species to N enrichment and increased precipitation by weakening the effect of the improved soil water status. The magnitude of the effect of shrubs on herbaceous biomass and richness was comparable to that of N enrichment and increased precipitation. Our results highlight the importance and complexity of both large-scale environmental changes and small-scale interspecific interactions in structuring plant communities in desert ecosystems. Moreover, abiotic environmental factors and biotic interactions should be integrated in efforts to predict the responses of plant communities to future global change in desert ecosystems.
Collapse
Affiliation(s)
- Yuxuan Bai
- Yanchi Research Station, School of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, China
| | - Weiwei She
- Yanchi Research Station, School of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, China
| | - Yuqing Zhang
- Yanchi Research Station, School of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, China; Key Laboratory of State Forestry Administration on Soil and Water Conservation, Beijing Forestry University, Beijing, China.
| | - Yangui Qiao
- Yanchi Research Station, School of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, China
| | - Jie Fu
- Yanchi Research Station, School of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, China
| | - Shugao Qin
- Yanchi Research Station, School of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, China; Engineering Research Centre of Forestry Ecological Engineering, Ministry of Education, Beijing Forestry University, Beijing, China
| |
Collapse
|
32
|
Lam WN, Chisholm RA. Resource conversion: a generalizable mechanism for resource‐mediated positive species interactions. OIKOS 2019. [DOI: 10.1111/oik.06672] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Weng Ngai Lam
- Dept of Biological Sciences, National Univ. of Singapore 14 Science Drive 4 Singapore 117543 Republic of Singapore
| | - Ryan A. Chisholm
- Dept of Biological Sciences, National Univ. of Singapore 14 Science Drive 4 Singapore 117543 Republic of Singapore
| |
Collapse
|
33
|
Ma S, De Frenne P, Wasof S, Brunet J, Cousins SAO, Decocq G, Kolb A, Lemke I, Liira J, Naaf T, Orczewska A, Plue J, Wulf M, Verheyen K. Plant-soil feedbacks of forest understorey plants transplanted in nonlocal soils along a latitudinal gradient. PLANT BIOLOGY (STUTTGART, GERMANY) 2019; 21:677-687. [PMID: 30659728 DOI: 10.1111/plb.12960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2018] [Accepted: 01/14/2019] [Indexed: 06/09/2023]
Abstract
Climate change is driving movements of many plants beyond, as well as within, their current distributional ranges. Even migrant plants moving within their current range may experience different plant-soil feedbacks (PSF) because of divergent nonlocal biotic soil conditions. Yet, our understanding to what extent soil biotic conditions can affect the performance of within-range migrant plants is still very limited. We assessed the emergence and growth of migrant forest herbs (Milium effusum and Stachys sylvatica) using soils and seeds collected along a 1,700 km latitudinal gradient across Europe. Soil biota were manipulated through four soil treatments, i.e. unsterilized control soil (PSFUS ), sterilized soil (PSFS ), sterilized soil inoculated with unsterilized home soil (PSFS+HI ) and sterilized soil inoculated with unsterilized foreign soil (PSFS+FI , expected to occur when both plants and soil biota track climate change). Compared to PSFS , PSFUS had negative effects on the growth but not emergence of both species, while PSFS+FI only affected S. sylvatica across all seed provenances. When considering seed origin, seedling emergence and growth responses to nonlocal soils depended on soil biotic conditions. Specifically, the home-away distance effect on seedling emergence differed between the four treatments, and significant responses to chemistry either disappeared (M. effusum) or changed (S. sylvatica) from PSFUS to PSFS . Soil biota emerge as an important driver of the estimated plant migration success. Our results of the effects of soil microorganisms on plant establishment provide relevant information for predictions of the distribution and dynamics of plant species in a changing climate.
Collapse
Affiliation(s)
- S Ma
- Forest & Nature Lab, Ghent University, Melle-Gontrode, Belgium
| | - P De Frenne
- Forest & Nature Lab, Ghent University, Melle-Gontrode, Belgium
| | - S Wasof
- Forest & Nature Lab, Ghent University, Melle-Gontrode, Belgium
| | - J Brunet
- Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences, Alnarp, Sweden
| | - S A O Cousins
- Department of Physical Geography, Stockholm University, Stockholm, Sweden
| | - G Decocq
- Plant Biodiversity Lab, University of Picardy Jules Verne, Amiens, France
| | - A Kolb
- Vegetation Ecology and Conservation Biology, Faculty of Biology/Chemistry (FB 02), University of Bremen, Bremen, Germany
| | - I Lemke
- Vegetation Ecology and Conservation Biology, Faculty of Biology/Chemistry (FB 02), University of Bremen, Bremen, Germany
| | - J Liira
- Department of Botany, University of Tartu, Tartu, Estonia
| | - T Naaf
- Leibniz Centre for Agricultural Landscape Research (ZALF), Müncheberg, Germany
| | - A Orczewska
- Department of Ecology, Faculty of Biology and Environmental Protection, University of Silesia, Katowice, Poland
| | - J Plue
- Department of Physical Geography, Stockholm University, Stockholm, Sweden
- School of Natural Sciences, Technology and Environmental Studies, Södertörn University, Stockholm, Sweden
| | - M Wulf
- Leibniz Centre for Agricultural Landscape Research (ZALF), Müncheberg, Germany
| | - K Verheyen
- Forest & Nature Lab, Ghent University, Melle-Gontrode, Belgium
| |
Collapse
|
34
|
Lucero JE, Noble T, Haas S, Westphal M, Butterfield H, Lortie CJ. The dark side of facilitation: native shrubs facilitate exotic annuals more strongly than native annuals. NEOBIOTA 2019. [DOI: 10.3897/neobiota.44.33771] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Positive interactions enhance biodiversity and ecosystem function, but can also exacerbate biological invasions. Facilitation of exotic invaders by exotic foundation species (invasional meltdown) has been studied extensively, but facilitation of exotic invaders by native foundation species has attracted less attention. Specifically, very few studies have examined the extent that native foundation species facilitate native and exotic competitors. Understanding the processes that mediate interactions between native and exotic species can help explain, predict, and improve management of biological invasions. Here, we examined the effects of native foundation shrubs on the relative abundance of the annual plant community – including native and exotic taxa – from 2015–2018 in a desert ecosystem at Carrizo Plain National Monument, California, USA (elevation: 723 m). Shrub effects varied by year and by the identity of annual species, but shrubs consistently enhanced the abundance of the annual plant community and facilitated both native (n=17 species) and exotic (n=4 species) taxa. However, at the provenance level, exotic annuals were facilitated 2.75 times stronger in abundance than native annuals, and exotic annuals were always more abundant than natives both near and away from shrubs. Our study reaffirms facilitation as an important process in the organisation of plant communities and confirms that both native and exotic species can form positive associations with native foundation species. However, facilitation by native foundation species can exacerbate biological invasions by increasing the local abundance of exotic invaders. Thus, the force of facilitation can have a dark side relevant to ecosystem function and management.
Collapse
|
35
|
Ploughe LW, Jacobs EM, Frank GS, Greenler SM, Smith MD, Dukes JS. Community Response to Extreme Drought (CRED): a framework for drought-induced shifts in plant-plant interactions. THE NEW PHYTOLOGIST 2019; 222:52-69. [PMID: 30449035 DOI: 10.1111/nph.15595] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 10/31/2018] [Indexed: 06/09/2023]
Abstract
Contents Summary 52 I. Introduction 52 II. The Community Response to Extreme Drought (CRED) framework 55 III. Post-drought rewetting rates: system and community recovery 61 IV. Site-specific characteristics influencing community resistance and resilience 63 V. Conclusions 64 Acknowledgements 65 References 66 SUMMARY: As climate changes, many regions of the world are projected to experience more intense droughts, which can drive changes in plant community composition through a variety of mechanisms. During drought, community composition can respond directly to resource limitation, but biotic interactions modify the availability of these resources. Here, we develop the Community Response to Extreme Drought framework (CRED), which organizes the temporal progression of mechanisms and plant-plant interactions that may lead to community changes during and after a drought. The CRED framework applies some principles of the stress gradient hypothesis (SGH), which proposes that the balance between competition and facilitation changes with increasing stress. The CRED framework suggests that net biotic interactions (NBI), the relative frequency and intensity of facilitative (+) and competitive (-) interactions between plants, will change temporally, becoming more positive under increasing drought stress and more negative as drought stress decreases. Furthermore, we suggest that rewetting rates affect the rate of resource amelioration, specifically water and nitrogen, altering productivity responses and the intensity and importance of NBI, all of which will influence drought-induced compositional changes. System-specific variables and the intensity of drought influence the strength of these interactions, and ultimately the system's resistance and resilience to drought.
Collapse
Affiliation(s)
- Laura W Ploughe
- Department of Biological Sciences, Purdue University, 915 W. State St., West Lafayette, IN, 47907, USA
| | - Elin M Jacobs
- Department of Forestry and Natural Resources, Purdue University, 715 W. State St., West Lafayette, IN, 47907, USA
| | - Graham S Frank
- Department of Forestry and Natural Resources, Purdue University, 715 W. State St., West Lafayette, IN, 47907, USA
| | - Skye M Greenler
- Department of Forestry and Natural Resources, Purdue University, 715 W. State St., West Lafayette, IN, 47907, USA
| | - Melinda D Smith
- Department of Biology, Graduate Degree Program in Ecology, Colorado State University, 251 W. Pitkin St., Fort Collins, CO, 80523, USA
| | - Jeffrey S Dukes
- Department of Biological Sciences, Purdue University, 915 W. State St., West Lafayette, IN, 47907, USA
- Department of Forestry and Natural Resources, Purdue University, 715 W. State St., West Lafayette, IN, 47907, USA
| |
Collapse
|
36
|
Verwijmeren M, Smit C, Bautista S, Wassen MJ, Rietkerk M. Combined Grazing and Drought Stress Alter the Outcome of Nurse: Beneficiary Interactions in a Semi-arid Ecosystem. Ecosystems 2019. [DOI: 10.1007/s10021-019-00336-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
37
|
Barry KE, Mommer L, van Ruijven J, Wirth C, Wright AJ, Bai Y, Connolly J, De Deyn GB, de Kroon H, Isbell F, Milcu A, Roscher C, Scherer-Lorenzen M, Schmid B, Weigelt A. The Future of Complementarity: Disentangling Causes from Consequences. Trends Ecol Evol 2018; 34:167-180. [PMID: 30527960 DOI: 10.1016/j.tree.2018.10.013] [Citation(s) in RCA: 120] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 10/29/2018] [Accepted: 10/30/2018] [Indexed: 11/30/2022]
Abstract
Evidence suggests that biodiversity supports ecosystem functioning. Yet, the mechanisms driving this relationship remain unclear. Complementarity is one common explanation for these positive biodiversity-ecosystem functioning relationships. Yet, complementarity is often indirectly quantified as overperformance in mixture relative to monoculture (e.g., 'complementarity effect'). This overperformance is then attributed to the intuitive idea of complementarity or, more specifically, to species resource partitioning. Locally, however, several unassociated causes may drive this overperformance. Here, we differentiate complementarity into three types of species differences that may cause enhanced ecosystem functioning in more diverse ecosystems: (i) resource partitioning, (ii) abiotic facilitation, and (iii) biotic feedbacks. We argue that disentangling these three causes is crucial for predicting the response of ecosystems to future biodiversity loss.
Collapse
Affiliation(s)
- Kathryn E Barry
- Systematic Botany and Functional Biodiversity, Institute of Biology, Leipzig University, Johannisallee 21-23, 04103 Leipzig, Germany; German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5e, 04103 Leipzig, Germany.
| | - Liesje Mommer
- Plant Ecology and Nature Conservation Group, Wageningen University, PO Box 47, NL-6700 AA Wageningen, The Netherlands
| | - Jasper van Ruijven
- Plant Ecology and Nature Conservation Group, Wageningen University, PO Box 47, NL-6700 AA Wageningen, The Netherlands
| | - Christian Wirth
- Systematic Botany and Functional Biodiversity, Institute of Biology, Leipzig University, Johannisallee 21-23, 04103 Leipzig, Germany; German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5e, 04103 Leipzig, Germany; Fellowship Group Functional Biogeography, Max-Planck Institute for Biogeochemistry, Hans-Knöll-Str. 10, 07745 Jena, Germany
| | - Alexandra J Wright
- Department of Biological Sciences, California State University - Los Angeles, 5151 State University Dr., Los Angeles, CA 90032-8201, USA
| | - Yongfei Bai
- State Key Laboratory of Vegetation and Environmental Change, Plant Ecology Centre, Institute of Botany, Chinese Academy of Sciences, No. 20 Nanxincun, Xiangshan, Beijing 100093, China
| | - John Connolly
- School of Mathematics and Statistics, Ecological and Environmental Modelling Group, University College Dublin, Dublin 4, Ireland
| | - Gerlinde B De Deyn
- Soil Biology and Biological Soil Quality Group, Wageningen University, PO Box 47, NL-6700 AA Wageningen, The Netherlands
| | - Hans de Kroon
- Department of Experimental Plant Ecology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, NL-6525 AJ Nijmegen, The Netherlands
| | - Forest Isbell
- Department of Ecology, Evolution, and Behavior, University of Minnesota, Saint Paul, MN 55108, USA
| | - Alexandru Milcu
- Centre national de la recherche scientifique, Ecotron (UPS-3248), Montferrier-sur-Lez, France; Centre d'Ecologie Fonctionnelle et Evolutive, CEFE-CNRS, UMR 5175, Université de Montpellier, Université Paul Valéry, EPHE, IRD, Montpellier Cedex 5, France
| | - Christiane Roscher
- Department of Physiological Diversity, UFZ - Helmholtz Centre for Environmental Research, 04318 Leipzig, Permoserstrasse 15, Germany; Plant Ecology and Nature Conservation Group, Wageningen University, PO Box 47, NL-6700 AA Wageningen, The Netherlands
| | - Michael Scherer-Lorenzen
- Faculty of Biology, Geobotany, University of Freiburg, Schänzlestrasse 1, 79104 Freiburg, Germany
| | - Bernhard Schmid
- Department of Geography, University of Zürich, Zürich, Switzerland
| | - Alexandra Weigelt
- Systematic Botany and Functional Biodiversity, Institute of Biology, Leipzig University, Johannisallee 21-23, 04103 Leipzig, Germany; German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5e, 04103 Leipzig, Germany
| |
Collapse
|
38
|
Westphal MF, Noble T, Butterfield HS, Lortie CJ. A test of desert shrub facilitation via radiotelemetric monitoring of a diurnal lizard. Ecol Evol 2018; 8:12153-12162. [PMID: 30598807 PMCID: PMC6303751 DOI: 10.1002/ece3.4673] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Revised: 09/13/2018] [Accepted: 09/18/2018] [Indexed: 12/03/2022] Open
Abstract
Preservation of desert ecosystems is a worldwide conservation priority. Shrubs can play a key role in the structure of desert communities and can function as foundation species. Understanding desert shrub ecology is therefore an important task in desert conservation. A useful model for the function of shrubs in deserts is ecological facilitation, which explores benefits that shrubs confer on their community. Facilitation has been well developed in the context of shrub-plant interactions but less well studied for plant-animal interactions. We used radiotelemetry to test the hypothesis that a dominant desert shrub facilitates one species of diurnal lizard. We hypothesized that the blunt-nosed leopard lizard Gambelia sila would spend some part of its daily activity cycle associated with California jointfir Ephedra californica, and that lizard association with shrubs would increase during the afternoon peak temperature period. We relocated lizards three times daily for 24 days and scored whether lizards were within 0.5 m of a shrub, which we used as an indicator of shrub association. For each relocation, we also scored lizard association with a set of predefined microhabitat features. We also scored lizard behavior according to a set of predefined behavioral traits. We constructed home ranges following the minimum convex polygon method and generated estimates of shrub density and relative shrub area within each home range polygon. We obtained 1,190 datapoints from a sample of 27 lizards. We found that lizards were associated with open sites significantly more often than with shrubs but were associated with shrubs more than predicted by percent shrub area within their home ranges. Lizards were associated significantly more often under shrubs during the afternoon peak temperature period, and lizards were observed cooling under shrubs significantly more often. The frequency of association of individual lizards with shrubs was not correlated with the density of shrubs within their home range. Synthesis and Applications. Shrubs can be considered as a component of high-quality habitat for ectothermic desert vertebrates for the purposes of restoration and management. Furthermore, radiotelemetry provides a novel methodological approach for assessing shrub-animal facilitative interactions within desert communities.
Collapse
Affiliation(s)
| | - Taylor Noble
- Department of BiologyYork UniversityTorontoOntarioCanada
| | | | | |
Collapse
|
39
|
Joint impact of competition, summer precipitation, and maternal effects on survival and reproduction in the perennial Hieracium umbellatum. Evol Ecol 2018. [DOI: 10.1007/s10682-018-9953-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
40
|
Dangles O, Herrera M, Carpio C, Lortie CJ. Facilitation costs and benefits function simultaneously on stress gradients for animals. Proc Biol Sci 2018; 285:rspb.2018.0983. [PMID: 30135157 DOI: 10.1098/rspb.2018.0983] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Accepted: 07/23/2018] [Indexed: 11/12/2022] Open
Abstract
Understanding the variation in species interactions along environmental stress gradients is crucial for making robust ecological predictions about community responses to changing environmental conditions. The facilitation-competition framework has provided a strong basis for predictions (e.g. the stress-gradient hypothesis, SGH), yet the mechanisms behind patterns in animal interactions on stress gradients are poorly explored in particular for mobile animals. Here, we proposed a conceptual framework modelling changes in facilitation costs and benefits along stress gradients and experimentally tested this framework by measuring fitness outcomes of benefactor-beneficiary interactions across resource quality levels. Three arthropod consumer models from a broad array of environmental conditions were used including aquatic detritivores, potato moths and rainforest carrion beetles. We detected a shift to more positive interactions at increasing levels of stress thereby supporting the application of the SGH to mobile animals. While most benefactors paid no significant cost of facilitation, an increase in potato moth beneficiary's growth at high resource stress triggered costs for benefactors. This study is the first to experimentally show that both costs and benefits function simultaneously on stress gradients for animals. The proposed conceptual framework could guide future studies examining species interaction outcomes for both animals and plants in an increasingly stressed world.
Collapse
Affiliation(s)
- Olivier Dangles
- Institut de Recherche pour le Développement, Centre d'Ecologie Fonctionnelle et Evolutive, UMR 5175, CNRS, Université de Montpellier, Université Paul Valéry, Montpellier, EPHE, IRD, Montpellier, France .,Department of Ecology and Evolutionary Biology, Cornell University, Corson Hall, Ithaca, NY, USA
| | - Mario Herrera
- Pontificia Universidad Católica del Ecuador, Facultad de Ciencias Exactas y Naturales, Quito, Ecuador
| | - Carlos Carpio
- Escuela Politécnica de Chimborazo, Facultad de recursos naturales, Riobamba, Ecuador
| | | |
Collapse
|
41
|
Porras M, De Moraes CM, Mescher MC, Rajotte EG, Carlo TA. A plant virus (BYDV) promotes trophic facilitation in aphids on wheat. Sci Rep 2018; 8:11709. [PMID: 30076391 PMCID: PMC6076312 DOI: 10.1038/s41598-018-30023-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Accepted: 07/21/2018] [Indexed: 11/09/2022] Open
Abstract
Pathogens and other parasites can have profound effects on biological communities and ecosystems. Here we explore how two strains of a plant virus - Barley Yellow Dwarf Virus, BYDV - influence the foraging performance and fecundity of two aphid species: Rhopalosiphum maidis and R. padi. We found that pre-inhabitation by R. padi on plants facilitates the subsequent foraging of conspecifics and R. maidis. Without the virus, the occurrence of facilitation is asymmetric because it depends on the order of species arrival. However, with virus we found facilitation irrespective of the order of species arrival. Furthermore, the virus also boosted the fecundity of both aphids. Analyses of nutrient content of virus-free and virus-infected plants show significant increases of essential amino acids, sterols, and carbohydrates. Such nutrient increases appear to underlie the facilitative interactions and fecundity of aphids on virus-infected plants. Our experiments demonstrate that the virus dramatically increases the food consumption and fecundity of aphids through intra and interspecific trophic facilitation, resulting in processes that could affect community organization.
Collapse
Affiliation(s)
- Mitzy Porras
- Entomology Department, The Pennsylvania State University, 501 ASI Bldg. University Park, State College, PA, 16802, USA. .,Biology Department, The Pennsylvania State University, 208 Mueller Lab, University Park, State College, PA, 16802, USA.
| | - Consuelo M De Moraes
- Biology Department, The Pennsylvania State University, 208 Mueller Lab, University Park, State College, PA, 16802, USA.,Department of Environmental Systems Science, Swiss Federal Institute of Technology (ETH Zürich), CH-8092, Zurich, Switzerland
| | - Mark C Mescher
- Biology Department, The Pennsylvania State University, 208 Mueller Lab, University Park, State College, PA, 16802, USA.,Department of Environmental Systems Science, Swiss Federal Institute of Technology (ETH Zürich), CH-8092, Zurich, Switzerland
| | - Edwin G Rajotte
- Entomology Department, The Pennsylvania State University, 501 ASI Bldg. University Park, State College, PA, 16802, USA
| | - Tomás A Carlo
- Biology Department, The Pennsylvania State University, 208 Mueller Lab, University Park, State College, PA, 16802, USA.,Intercollege Graduate Ecology Program, The Pennsylvania State University, 208 Mueller Lab, University Park, State College, PA, 16802, USA
| |
Collapse
|
42
|
Chardon NI, Wipf S, Rixen C, Beilstein A, Doak DF. Local trampling disturbance effects on alpine plant populations and communities: Negative implications for climate change vulnerability. Ecol Evol 2018; 8:7921-7935. [PMID: 30250673 PMCID: PMC6144962 DOI: 10.1002/ece3.4276] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Revised: 04/11/2018] [Accepted: 05/17/2018] [Indexed: 11/21/2022] Open
Abstract
Global change is modifying species communities from local to landscape scales, with alterations in the abiotic and biotic determinants of geographic range limits causing species range shifts along both latitudinal and elevational gradients. An important but often overlooked component of global change is the effect of anthropogenic disturbance, and how it interacts with the effects of climate to affect both species and communities, as well as interspecies interactions, such as facilitation and competition. We examined the effects of frequent human trampling disturbances on alpine plant communities in Switzerland, focusing on the elevational range of the widely distributed cushion plant Silene acaulis and the interactions of this facilitator species with other plants. Examining size distributions and densities, we found that disturbance appears to favor individual Silene growth at middle elevations. However, it has negative effects at the population level, as evidenced by a reduction in population density and reproductive indices. Disturbance synergistically interacts with the effects of elevation to reduce species richness at low and high elevations, an effect not mitigated by Silene. In fact, we find predominantly competitive interactions, both by Silene on its hosted and neighboring species and by neighboring (but not hosted) species on Silene. Our results indicate that disturbance can be beneficial for Silene individual performance, potentially through changes in its neighboring species community. However, possible reduced recruitment in disturbed areas could eventually lead to population declines. While other studies have shown that light to moderate disturbances can maintain high species diversity, our results emphasize that heavier disturbance reduces species richness, diversity, as well as percent cover, and adversely affects cushion plants and that these effects are not substantially reduced by plant-plant interactions. Heavily disturbed alpine systems could therefore be at greater risk for upward encroachment of lower elevation species in a warming world.
Collapse
Affiliation(s)
- Nathalie Isabelle Chardon
- Environmental Studies ProgramUniversity of ColoradoBoulderUSA
- Mountain EcosystemsWSL Institute for Snow and Avalanche Research SLFDavosSwitzerland
| | - Sonja Wipf
- Mountain EcosystemsWSL Institute for Snow and Avalanche Research SLFDavosSwitzerland
| | - Christian Rixen
- Mountain EcosystemsWSL Institute for Snow and Avalanche Research SLFDavosSwitzerland
| | - Annabarbara Beilstein
- Mountain EcosystemsWSL Institute for Snow and Avalanche Research SLFDavosSwitzerland
- Department of Environmental Systems ScienceETH ZurichZurichSwitzerland
| | | |
Collapse
|
43
|
Pistón N, Michalet R, Schöb C, Macek P, Armas C, Pugnaire FI. The balance of canopy and soil effects determines intraspecific differences in foundation species’ effects on associated plants. Funct Ecol 2018. [DOI: 10.1111/1365-2435.13139] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Nuria Pistón
- Estación Experimental de Zonas Áridas (EEZA‐CSIC) Almería Spain
- Nuria Pistón, Departamento de EcologíaInstituto de BiologiaUniversidade Federal do Rio de Janeiro (UFRJ) Rio de Janeiro Brazil
| | | | - Christian Schöb
- Estación Experimental de Zonas Áridas (EEZA‐CSIC) Almería Spain
- Christian Schöb, Department of Environmental System ScienceSwiss Federal Institute of TechnologyETH Zurich Tannenstrasse 1 8092 Zürich Switzerland
| | - Petr Macek
- Estación Experimental de Zonas Áridas (EEZA‐CSIC) Almería Spain
- Petr Macek, Faculty of ScienceUniversity of South Bohemia Branišovská 1760 CZ‐370 05 České Budějovice Czech Republic
| | - Cristina Armas
- Estación Experimental de Zonas Áridas (EEZA‐CSIC) Almería Spain
| | | |
Collapse
|
44
|
Du N, Wu P, Eller F, Zhou D, Liu J, Gan W, Yang R, Dai M, Chen Y, Wang R, Guo W. Facilitation or Competition? The Effects of the Shrub Species Tamarix chinensis on Herbaceous Communities are Dependent on the Successional Stage in an Impacted Coastal Wetland of North China. WETLANDS 2017; 37:899-911. [DOI: 10.1007/s13157-017-0923-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2024]
|
45
|
Jiang X, Michalet R, Chen S, Zhao L, Wang X, Wang C, An L, Xiao S. Phenotypic effects of the nurseThylacospermum caespitosumon dependent plant species along regional climate stress gradients. OIKOS 2017. [DOI: 10.1111/oik.04512] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Xingpei Jiang
- State Key Laboratory of Grassland and Agro-ecosystems, School of Life Sciences, Lanzhou Univ., 222 Tianshuinan Road; CN-730000 Lanzhou PR China
| | - Richard Michalet
- Univ. of Bordeaux, U.M.R. CNRS, Allée Geoffroy Saint-Hilaire; Pessac France
| | - Shuyan Chen
- Ministry of Education Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Chongqing Univ.; Chongqing PR China
| | - Liang Zhao
- Ministry of Education Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Chongqing Univ.; Chongqing PR China
| | - Xiangtai Wang
- State Key Laboratory of Grassland and Agro-ecosystems, School of Life Sciences, Lanzhou Univ., 222 Tianshuinan Road; CN-730000 Lanzhou PR China
| | - Chenyue Wang
- State Key Laboratory of Grassland and Agro-ecosystems, School of Life Sciences, Lanzhou Univ., 222 Tianshuinan Road; CN-730000 Lanzhou PR China
| | - Lizhe An
- State Key Laboratory of Grassland and Agro-ecosystems, School of Life Sciences, Lanzhou Univ., 222 Tianshuinan Road; CN-730000 Lanzhou PR China
| | - Sa Xiao
- State Key Laboratory of Grassland and Agro-ecosystems, School of Life Sciences, Lanzhou Univ., 222 Tianshuinan Road; CN-730000 Lanzhou PR China
| |
Collapse
|
46
|
Carvalho JM, Ramos SJ, Furtini Neto AE, Gastauer M, Caldeira CF, Siqueira JO, Silva MLS. Influence of nutrient management on growth and nutrient use efficiency of two plant species for mineland revegetation. Restor Ecol 2017. [DOI: 10.1111/rec.12572] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- João M. Carvalho
- Departamento de Ciência do Solo; Universidade Federal de Lavras; Lavras Minas Gerais 37200-000 Brazil
| | - Silvio J. Ramos
- Instituto Tecnológico Vale; Rua Boaventura da Silva; 955 Belém, Pará 66055-090 Brazil
- Departamento de Botânica Aplicada; Universidade Federal de Lavras; Lavras Minas Gerais 37200-000 Brazil
| | | | - Markus Gastauer
- Instituto Tecnológico Vale; Rua Boaventura da Silva; 955 Belém, Pará 66055-090 Brazil
| | - Cecilio F. Caldeira
- Instituto Tecnológico Vale; Rua Boaventura da Silva; 955 Belém, Pará 66055-090 Brazil
| | - José O. Siqueira
- Departamento de Ciência do Solo; Universidade Federal de Lavras; Lavras Minas Gerais 37200-000 Brazil
- Instituto Tecnológico Vale; Rua Boaventura da Silva; 955 Belém, Pará 66055-090 Brazil
| | - Maria L. S. Silva
- Departamento de Ciência do Solo; Universidade Federal de Lavras; Lavras Minas Gerais 37200-000 Brazil
| |
Collapse
|
47
|
Role of co-occurring competition and facilitation in plant spacing hydrodynamics in water-limited environments. Proc Natl Acad Sci U S A 2017; 114:9379-9384. [PMID: 28807999 DOI: 10.1073/pnas.1706046114] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Plant performance (i.e., fecundity, growth, survival) depends on an individual's access to space and resources. At the community level, plant performance is reflected in observable vegetation patterning (i.e., spacing distance, density) often controlled by limiting resources. Resource availability is, in turn, strongly dependent on plant patterning mediated by competitive and facilitative plant-plant interactions. Co-occurring competition and facilitation has never been specifically investigated from a hydrodynamic perspective. To address this knowledge gap, and to overcome limitations of field studies, three intermediate-scale laboratory experiments were conducted using a climate-controlled wind tunnel-porous media test facility to simulate the soil-plant-atmosphere continuum. The spacing between two synthetic plants, a design consideration introduced by the authors in a recent publication, was varied between experiments; edaphic and mean atmospheric conditions were held constant. The strength of the above- and belowground plant-plant interactions changed with spacing distance, allowing the creation of a hydrodynamic conceptual model based on established ecological theories. Greatest soil water loss was observed for the experiment with the smallest spacing where competition dominated. Facilitation dominated at the intermediate spacing; little to no interactions were observed for the largest plant spacing. Results suggest that there exists an optimal spacing distance range that lowers plant environmental stress, thus improving plant performance through reduced atmospheric demand and conservation of available soil water. These findings may provide a foundation for improving our understanding of many climatological, ecohydrological, and hydrological problems pertaining to the hydrodynamics of water-limited environments where plant-plant interactions and community self-organization are important.
Collapse
|
48
|
Zhang H, Lü X, Knapp AK, Hartmann H, Bai E, Wang X, Wang Z, Wang X, Yu Q, Han X. Facilitation by leguminous shrubs increases along a precipitation gradient. Funct Ecol 2017. [DOI: 10.1111/1365-2435.12941] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Hai‐Yang Zhang
- Erguna Forest‐Steppe Ecotone Research StationInstitute of Applied EcologyChinese Academy of Sciences Shenyang China
- Max Planck Institute for Biogeochemistry Jena Germany
| | - Xiao‐Tao Lü
- Erguna Forest‐Steppe Ecotone Research StationInstitute of Applied EcologyChinese Academy of Sciences Shenyang China
| | - Alan K. Knapp
- Department of BiologyColorado State University Fort Collins CO USA
| | | | - Edith Bai
- Erguna Forest‐Steppe Ecotone Research StationInstitute of Applied EcologyChinese Academy of Sciences Shenyang China
| | - Xiao‐Bo Wang
- Erguna Forest‐Steppe Ecotone Research StationInstitute of Applied EcologyChinese Academy of Sciences Shenyang China
| | - Zheng‐Wen Wang
- Erguna Forest‐Steppe Ecotone Research StationInstitute of Applied EcologyChinese Academy of Sciences Shenyang China
| | - Xiao‐Guang Wang
- College of Environment and ResourcesDalian Minzu University Dalian China
| | - Qiang Yu
- National Hulunber Grassland Ecosystem Observation and Research Station/Institute of Agricultural Resources and Regional PlanningChinese Academy of Agricultural Sciences Beijing China
| | - Xing‐Guo Han
- State Key Laboratory of Vegetation and Environmental ChangeInstitute of BotanyChinese Academy of Sciences Beijing China
| |
Collapse
|
49
|
Nelson KA, Collins SF, Sass GG, Wahl DH. A response‐surface examination of competition and facilitation between native and invasive juvenile fishes. Funct Ecol 2017. [DOI: 10.1111/1365-2435.12922] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Kirsten A. Nelson
- Illinois Natural History Survey, Kaskaskia Biological Station Sullivan IL USA
- Illinois Natural History SurveyUniversity of Illinois Champaign‐Urbana Champaign IL USA
| | - Scott F. Collins
- Illinois Natural History Survey, Kaskaskia Biological Station Sullivan IL USA
| | - Greg G. Sass
- Illinois Natural History SurveyUniversity of Illinois Champaign‐Urbana Champaign IL USA
| | - David H. Wahl
- Illinois Natural History Survey, Kaskaskia Biological Station Sullivan IL USA
- Illinois Natural History SurveyUniversity of Illinois Champaign‐Urbana Champaign IL USA
| |
Collapse
|
50
|
Liancourt P, Le Bagousse-Pinguet Y, Rixen C, Dolezal J. SGH: stress or strain gradient hypothesis? Insights from an elevation gradient on the roof of the world. ANNALS OF BOTANY 2017; 120:29-38. [PMID: 28444363 PMCID: PMC5737727 DOI: 10.1093/aob/mcx037] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 03/15/2017] [Indexed: 06/01/2023]
Abstract
BACKGROUND AND AIMS The stress gradient hypothesis (SGH), the view that competition prevails in undisturbed and productive environments, and shifts to facilitation in disturbed or stressful environments, has become a central paradigm in ecology. However, an alternative view proposes that the relationship between biotic interactions and environmental severity should be unimodal instead of monotonic. Possible causes of discrepancies between these two views were examined in the high elevation desert of the arid Trans-Himalayas. METHODS A putative nurse species and its associated plant community was surveyed over its entire elevation range, spanning from alpine to desert vegetation belts. The results were analysed at the community level (vegetation cover and species richness), considering the distinction between the intensity and the importance of biotic interactions. Interactions at the species level (pairwise interactions) were also considered, i.e. the variation of biotic interactions within the niche of a species, for which the abundance (species cover) and probability of occurrence (presence/absence) for the most widespread species along the gradient were distinguished. KEY RESULTS Overall, facilitation was infrequent in our study system; however, it was observed for the two most widespread species. At the community level, the intensity and importance of biotic interactions showed a unimodal pattern. The departure from the prediction of the SGH happened abruptly where the nurse species entered the desert vegetation belt at the lowest elevation. This abrupt shift was attributed to the turnover of species with contrasting tolerances. At the species level, however, facilitation increased consistently as the level of stress increases and individuals deviate from their optimum (increasing strain). CONCLUSION While the stress gradient hypothesis was not supported along our elevation gradient at the community level, the strain gradient hypothesis, considering how species perceive the ambient level of stress and deviate from their optimum, provided a parsimonious explanation for the outcome of plant-plant interactions at both scales.
Collapse
Affiliation(s)
- Pierre Liancourt
- Institute of Botany, Czech Academy of Sciences, Dukelská 135, 379 82 Trebon, Czech Republic
| | - Yoann Le Bagousse-Pinguet
- Departamento de Biología y Geología, Física y Química Inorgánica, Escuela Superior de Ciencias Experimentales y Tecnología, Universidad Rey Juan Carlos, C/ Tulipán s/n, 28933 Móstoles, Spain
| | - Christian Rixen
- WSL Institute for Snow and Avalanche Research SLF, Davos Dorf, Switzerland
| | - Jiri Dolezal
- Institute of Botany, Czech Academy of Sciences, Dukelská 135, 379 82 Trebon, Czech Republic
- Department of Botany, Faculty of Science, University of South Bohemia, Na Zlate stoce 1, 370 05 Ceske Budejovice, Czech Republic
| |
Collapse
|