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Lortie CJ, Brown C, Haas-Desmarais S, Lucero J, Callaway R, Braun J, Filazzola A. Plant networks are more connected by invasive brome and native shrub facilitation in Central California drylands. Sci Rep 2024; 14:8958. [PMID: 38637667 PMCID: PMC11026385 DOI: 10.1038/s41598-024-59868-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 04/15/2024] [Indexed: 04/20/2024] Open
Abstract
Dominant vegetation in many ecosystems is an integral component of structure and habitat. In many drylands, native shrubs function as foundation species that benefit other plants and animals. However, invasive exotic plant species can comprise a significant proportion of the vegetation. In Central California drylands, the facilitative shrub Ephedra californica and the invasive Bromus rubens are widely dispersed and common. Using comprehensive survey data structured by shrub and open gaps for the region, we compared network structure with and without this native shrub canopy and with and without the invasive brome. The presence of the invasive brome profoundly shifted the network measure of centrality in the microsites structured by a shrub canopy (centrality scores increased from 4.3 under shrubs without brome to 6.3, i.e. a relative increase of 42%). This strongly suggests that plant species such as brome can undermine the positive and stabilizing effects of native foundation plant species provided by shrubs in drylands by changing the frequency that the remaining species connect to one another. The net proportion of positive and negative associations was consistent across all microsites (approximately 50% with a total of 14% non-random co-occurrences on average) suggesting that these plant-plant networks are rewired but not more negative. Maintaining resilience in biodiversity thus needs to capitalize on protecting native shrubs whilst also controlling invasive grass species particularly when associated with shrubs.
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Affiliation(s)
- C J Lortie
- Department of Biology, York University, Toronto, ON, M3J1P3, Canada
| | - Charlotte Brown
- Département de Biologie, Université de Sherbrooke, Voie 9, Sherbrooke, Québec, J1K 2R1, Canada
| | | | - Jacob Lucero
- Texas A & M, Department of Rangeland, Wildlife and Fisheries Management, 495 Horticulture Rd #305, College Station, TX, 77843-2183, USA
| | - Ragan Callaway
- Division of Biological Sciences, University of Montana, Missoula, MT, 59812, USA
| | - Jenna Braun
- Department of Biology, York University, Toronto, ON, M3J1P3, Canada
| | - Alessandro Filazzola
- Apex Resource Management Solutions, Ottawa, ON, Canada.
- Department of Biology, University of Western Ontario, London, ON, N6A 5B7, Canada.
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Sharmin M, Tjoelker MG, Esperon-Rodriguez M, Katlav A, Gilpin AM, Rymer PD, Power SA. Urban greening with shrubs can supercharge invertebrate abundance and diversity. Sci Rep 2024; 14:8735. [PMID: 38627432 PMCID: PMC11021404 DOI: 10.1038/s41598-024-58909-8] [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: 09/16/2023] [Accepted: 04/04/2024] [Indexed: 04/19/2024] Open
Abstract
In urban areas, diverse and complex habitats for biodiversity are often lacking. This lack of diversity not only compromises essential ecological processes, such as pollination and nutrient cycling, but also diminishes the resilience of urban ecosystems to pests and diseases. To enhance urban biodiversity, a possible solution is to integrate shrubs alongside trees, thereby increasing the overall amount of vegetation, structural complexity and the associated resource diversity. Here, using a common garden experiment involving a variety of trees and shrubs planted alone and in combination, we evaluate how canopy-associated invertebrate assemblages are influenced by vegetation type. In particular, we test whether the presence of shrubs, alone or with trees, results in increased abundance and taxonomic richness of invertebrates, compared to trees on their own. We found that the overall abundance of invertebrates, and that of specific functional groups (e.g., herbivores, pollinators, detritivores), was higher on shrubs, compared to trees, and when trees and shrubs were planted in combination (relative to trees on their own). Our results suggest that planting shrub and tree species with wide and dense crowns can increase the associated abundance and taxonomic and functional group richness of invertebrate communities. Overall, our findings indicate that urban planning would benefit from incorporating shrubs alongside urban trees to maximise invertebrate abundance, diversity and function in urban landscapes.
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Affiliation(s)
- Mahmuda Sharmin
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia.
- Department of Forestry and Environmental Science, Shahjalal University of Science and Technology, Sylhet, 3114, Bangladesh.
| | - Mark G Tjoelker
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia
| | - Manuel Esperon-Rodriguez
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia
- School of Science, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia
| | - Alihan Katlav
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia
| | - Amy-Marie Gilpin
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia
- School of Science, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia
| | - Paul D Rymer
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia
| | - Sally A Power
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia
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Zuliani M, Ghazian N, Owen M, Westphal MF, Butterfield HS, Lortie CJ. Shrub density effects on the presence of an endangered lizard of the Carrizo Plain National Monument, California. Ecol Evol 2023; 13:e10128. [PMID: 37214602 PMCID: PMC10199236 DOI: 10.1002/ece3.10128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 04/28/2023] [Accepted: 05/11/2023] [Indexed: 05/24/2023] Open
Abstract
Positive associations between animals and foundational shrub species are frequent in desert ecosystems for shelter, resources, refuge, and other key ecological processes. Herein, we tested the impact of the density of the shrub species Ephedra californica on the presence and habitat use of the federally endangered lizard species, Gambelia sila. To do this, we used a 3-year radio telemetry dataset and satellite-based counts of shrub density across sites at the Carrizo Plain National Monument in San Luis Obispo County, CA. The effect of shrub density on lizard presence was contrasted with previous shrub cover analyses to determine whether measures of shrub density were superior to shrub cover in predicting lizard presence. Increasing shrub density increased lizard presence. As shrub density increased, lizards were located more frequently "above ground" versus "below ground" in burrows. Male lizards had significantly larger home ranges than females, but both sexes were similarly associated with increasing shrub densities. Shrub density and shrub cover models did not significantly differ in their prediction of lizard presence. These findings suggest that both habitat measures are effective analogs and that ecologically, both cover and the density of foundation shrub species are key factors for some desert lizards.
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Affiliation(s)
- Mario Zuliani
- Department of Biological ScienceYork UniversityTorontoOntarioCanada
| | - Nargol Ghazian
- Department of Biological ScienceYork UniversityTorontoOntarioCanada
| | - Malory Owen
- Department of Biological ScienceYork UniversityTorontoOntarioCanada
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Zuliani M, Ghazian N, Lortie CJ. A meta‐analysis of shrub density as a predictor of animal abundance. WILDLIFE BIOLOGY 2023. [DOI: 10.1002/wlb3.01042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Affiliation(s)
- Mario Zuliani
- Dept of Biological Science, York Univ. Toronto ON Canada
| | - Nargol Ghazian
- Dept of Biological Science, York Univ. Toronto ON Canada
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Gaudenti N, Nix E, Maier P, Westphal MF, Taylor EN. Habitat heterogeneity affects the thermal ecology of an endangered lizard. Ecol Evol 2021; 11:14843-14856. [PMID: 34765145 PMCID: PMC8571645 DOI: 10.1002/ece3.8170] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 08/27/2021] [Accepted: 08/31/2021] [Indexed: 11/21/2022] Open
Abstract
Global climate change is already contributing to the extirpation of numerous species worldwide, and sensitive species will continue to face challenges associated with rising temperatures throughout this century and beyond. It is especially important to evaluate the thermal ecology of endangered ectotherm species now so that mitigation measures can be taken as early as possible. A recent study of the thermal ecology of the federally endangered Blunt-nosed Leopard Lizard (Gambelia sila) suggested that they face major activity restrictions due to thermal constraints in their desert habitat, but that large shade-providing shrubs act as thermal buffers to allow them to maintain surface activity without overheating. We replicated this study and also included a population of G. sila with no access to large shrubs to facilitate comparison of the thermal ecology of G. sila populations in shrubless and shrubbed sites. We found that G. sila without access to shrubs spent more time sheltering inside rodent burrows than lizards with access to shrubs, especially during the hot summer months. Lizards from a shrubbed site had higher midday body temperatures and therefore poorer thermoregulatory accuracy than G. sila from a shrubless site, suggesting that greater surface activity may represent a thermoregulatory trade-off for G. sila. Lizards at both sites are currently constrained from using open, sunny microhabitats for much of the day during their short active seasons, and our projections suggest that climate change will exacerbate these restrictions and force G. sila to use rodent burrows for shelter even more than they do now, especially at sites without access to shrubs. The continued management of shrubs and of burrowing rodents at G. sila sites is therefore essential to the survival of this endangered species.
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Affiliation(s)
- Nicole Gaudenti
- Biological Sciences DepartmentCalifornia Polytechnic State UniversitySan Luis ObispoCaliforniaUSA
| | - Emmeleia Nix
- Central Coast Field OfficeUS Bureau of Land ManagementMarinaCaliforniaUSA
| | - Paul Maier
- Biological Sciences DepartmentCalifornia Polytechnic State UniversitySan Luis ObispoCaliforniaUSA
| | | | - Emily N. Taylor
- Biological Sciences DepartmentCalifornia Polytechnic State UniversitySan Luis ObispoCaliforniaUSA
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