Risk of Facilitated Invasion Depends Upon Invader Identity, Not Environmental Severity, Along an Aridity Gradient
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 communi...
| Main Authors: | , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Frontiers Media S.A.
2022-05-01
|
| Series: | Frontiers in Ecology and Evolution |
| Subjects: | |
| Online Access: | https://www.frontiersin.org/articles/10.3389/fevo.2022.886690/full |
| _version_ | 1818270367175671808 |
|---|---|
| author | Jacob E. Lucero Jacob E. Lucero Jacob E. Lucero Akasha M. Faist Christopher J. Lortie Ragan M. Callaway |
| author_facet | Jacob E. Lucero Jacob E. Lucero Jacob E. Lucero Akasha M. Faist Christopher J. Lortie Ragan M. Callaway |
| author_sort | Jacob E. Lucero |
| collection | DOAJ |
| description | 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. |
| first_indexed | 2024-12-12T21:09:09Z |
| format | Article |
| id | doaj.art-d6cef15af7554ad081de123bc9c55182 |
| institution | Directory Open Access Journal |
| issn | 2296-701X |
| language | English |
| last_indexed | 2024-12-12T21:09:09Z |
| publishDate | 2022-05-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Ecology and Evolution |
| spelling | doaj.art-d6cef15af7554ad081de123bc9c551822022-12-22T00:11:57ZengFrontiers Media S.A.Frontiers in Ecology and Evolution2296-701X2022-05-011010.3389/fevo.2022.886690886690Risk of Facilitated Invasion Depends Upon Invader Identity, Not Environmental Severity, Along an Aridity GradientJacob E. Lucero0Jacob E. Lucero1Jacob E. Lucero2Akasha M. Faist3Christopher J. Lortie4Ragan M. Callaway5Department of Animal and Range Sciences, New Mexico State University, Las Cruces, NM, United StatesDepartment of Biology, York University, Toronto, ON, CanadaDivision of Biological Sciences and the Institute on Ecosystems, University of Montana, Missoula, MT, United StatesDepartment of Animal and Range Sciences, New Mexico State University, Las Cruces, NM, United StatesDepartment of Biology, York University, Toronto, ON, CanadaDivision of Biological Sciences and the Institute on Ecosystems, University of Montana, Missoula, MT, United StatesPositive 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.https://www.frontiersin.org/articles/10.3389/fevo.2022.886690/fulldesertfacilitated invasionfacilitationinvasive speciespositive interactionsshrubs |
| spellingShingle | Jacob E. Lucero Jacob E. Lucero Jacob E. Lucero Akasha M. Faist Christopher J. Lortie Ragan M. Callaway Risk of Facilitated Invasion Depends Upon Invader Identity, Not Environmental Severity, Along an Aridity Gradient Frontiers in Ecology and Evolution desert facilitated invasion facilitation invasive species positive interactions shrubs |
| title | Risk of Facilitated Invasion Depends Upon Invader Identity, Not Environmental Severity, Along an Aridity Gradient |
| title_full | Risk of Facilitated Invasion Depends Upon Invader Identity, Not Environmental Severity, Along an Aridity Gradient |
| title_fullStr | Risk of Facilitated Invasion Depends Upon Invader Identity, Not Environmental Severity, Along an Aridity Gradient |
| title_full_unstemmed | Risk of Facilitated Invasion Depends Upon Invader Identity, Not Environmental Severity, Along an Aridity Gradient |
| title_short | Risk of Facilitated Invasion Depends Upon Invader Identity, Not Environmental Severity, Along an Aridity Gradient |
| title_sort | risk of facilitated invasion depends upon invader identity not environmental severity along an aridity gradient |
| topic | desert facilitated invasion facilitation invasive species positive interactions shrubs |
| url | https://www.frontiersin.org/articles/10.3389/fevo.2022.886690/full |
| work_keys_str_mv | AT jacobelucero riskoffacilitatedinvasiondependsuponinvaderidentitynotenvironmentalseverityalonganariditygradient AT jacobelucero riskoffacilitatedinvasiondependsuponinvaderidentitynotenvironmentalseverityalonganariditygradient AT jacobelucero riskoffacilitatedinvasiondependsuponinvaderidentitynotenvironmentalseverityalonganariditygradient AT akashamfaist riskoffacilitatedinvasiondependsuponinvaderidentitynotenvironmentalseverityalonganariditygradient AT christopherjlortie riskoffacilitatedinvasiondependsuponinvaderidentitynotenvironmentalseverityalonganariditygradient AT raganmcallaway riskoffacilitatedinvasiondependsuponinvaderidentitynotenvironmentalseverityalonganariditygradient |