1
|
Baxter-Gilbert J, Riley JL, Wagener C, Baider C, Florens FBV, Kowalski P, Campbell M, Measey J. Island Hopping through Urban Filters: Anthropogenic Habitats and Colonized Landscapes Alter Morphological and Performance Traits of an Invasive Amphibian. Animals (Basel) 2022; 12:ani12192549. [PMID: 36230289 PMCID: PMC9559409 DOI: 10.3390/ani12192549] [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: 06/29/2022] [Revised: 07/28/2022] [Accepted: 09/19/2022] [Indexed: 11/17/2022] Open
Abstract
Simple Summary Invasive species are common on islands and, increasingly so, in urban ecosystems. They can pose serious ecological and socioeconomic impacts, making research on how invasions are promoted critically important. We examined different traits of guttural toads (Sclerophrys gutturalis) in their natural and invasive ranges (both natural and urban populations in native and invasive sites) to understand if divergences in habitats in their native range could increase their invasive potential. We found that invasive island populations on Mauritius and Réunion (Indian Ocean) have reduced body sizes, proportionally shorter limbs, slower escape speeds, and reduced endurance capacities compared to the native South African populations. In short, these changes occurred post-invasion. However, increase climbing ability was seen within the urban-native toads, a trait maintained within the two invasions, suggesting that it may have been an advantageous prior adaptation. Becoming climbers may have benefited the toad during colonization, increasing navigation and hunting ability within the urbanized areas where they were introduced, prior to their spread into natural areas. This change in climbing performance is an example of how the urbanization of native taxa may be increasing the ability of certain species to become better invaders should they be introduced outside their native range. Abstract A prominent feature of the modern era is the increasing spread of invasive species, particularly within island and urban ecosystems, and these occurrences provide valuable natural experiments by which evolutionary and invasion hypotheses can be tested. In this study, we used the invasion route of guttural toads (Sclerophrys gutturalis) from natural-native and urban-native populations (Durban, South Africa) to their urban-invasive and natural-invasive populations (Mauritius and Réunion) to determine whether phenotypic changes that arose once the toads became urbanized in their native range have increased their invasive potential before they were transported (i.e., prior adaptation) or whether the observed changes are unique to the invasive populations. This urban/natural by native/invasive gradient allowed us to examine differences in guttural toad morphology (i.e., body size, hindlimb, and hindfoot length) and performance capacity (i.e., escape speed, endurance, and climbing ability) along their invasion route. Our findings indicate that invasive island populations have reduced body sizes, shorter limbs in relation to snout-vent length, decreased escape speeds, and decreased endurance capacities that are distinct from the native mainland populations (i.e., invasion-derived change). Thus, these characteristics did not likely arise directly from a pre-transport anthropogenic “filter” (i.e., urban-derived change). Climbing ability, however, did appear to originate within the urban-native range and was maintained within the invasive populations, thereby suggesting it may have been a prior adaptation that provided this species with an advantage during its establishment in urban areas and spread into natural forests. We discuss how this shift in climbing performance may be ecologically related to the success of urban and invasive guttural toad populations, as well as how it may have impacted other island-derived morphological and performance phenotypes.
Collapse
Affiliation(s)
- James Baxter-Gilbert
- Centre for Invasion Biology, Department of Botany and Zoology, Stellenbosch University, Stellenbosch 7405, South Africa
- Department of Biology, Mount Allison University, Sackville, NB E4L 1E2, Canada
- Correspondence:
| | - Julia L. Riley
- Department of Biology, Mount Allison University, Sackville, NB E4L 1E2, Canada
- Department of Botany and Zoology, Stellenbosch University, Stellenbosch 7405, South Africa
- Department of Biology, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Carla Wagener
- Centre for Invasion Biology, Department of Botany and Zoology, Stellenbosch University, Stellenbosch 7405, South Africa
- Department of Zoology, University of Oxford, Oxford OX1 4BH, UK
| | - Cláudia Baider
- The Mauritius Herbarium, Agricultural Services, Ministry of Agro-Industry and Food Security, Réduit 80835, Mauritius
| | - F. B. Vincent Florens
- Tropical Island Biodiversity, Ecology and Conservation Pole of Research, Faculty of Science, University of Mauritius, Réduit 80837, Mauritius
| | | | - May Campbell
- Grow Learning Support, Ballito 4391, South Africa
| | - John Measey
- Centre for Invasion Biology, Department of Botany and Zoology, Stellenbosch University, Stellenbosch 7405, South Africa
| |
Collapse
|
4
|
Malhotra A, Wüster W, Owens JB, Hodges CW, Jesudasan A, Ch G, Kartik A, Christopher P, Louies J, Naik H, Santra V, Kuttalam SR, Attre S, Sasa M, Bravo-Vega C, Murray KA. Promoting co-existence between humans and venomous snakes through increasing the herpetological knowledge base. Toxicon X 2021; 12:100081. [PMID: 34522881 PMCID: PMC8426276 DOI: 10.1016/j.toxcx.2021.100081] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 07/28/2021] [Accepted: 08/04/2021] [Indexed: 11/23/2022] Open
Abstract
Snakebite incidence at least partly depends on the biology of the snakes involved. However, studies of snake biology have been largely neglected in favour of anthropic factors, with the exception of taxonomy, which has been recognised for some decades to affect the design of antivenoms. Despite this, within-species venom variation and the unpredictability of the correlation with antivenom cross-reactivity has continued to be problematic. Meanwhile, other aspects of snake biology, including behaviour, spatial ecology and activity patterns, distribution, and population demography, which can contribute to snakebite mitigation and prevention, remain underfunded and understudied. Here, we review the literature relevant to these aspects of snakebite and illustrate how demographic, spatial, and behavioural studies can improve our understanding of why snakebites occur and provide evidence for prevention strategies. We identify the large gaps that remain to be filled and urge that, in the future, data and relevant metadata be shared openly via public data repositories so that studies can be properly replicated and data used in future meta-analyses.
Collapse
Affiliation(s)
- Anita Malhotra
- Molecular Ecology and Evolution @ Bangor, School of Natural Sciences, Bangor University, 3rd floor ECW, Deiniol Road, Bangor, LL57 2UW, UK
| | - Wolfgang Wüster
- Molecular Ecology and Evolution @ Bangor, School of Natural Sciences, Bangor University, 3rd floor ECW, Deiniol Road, Bangor, LL57 2UW, UK
| | - John Benjamin Owens
- Molecular Ecology and Evolution @ Bangor, School of Natural Sciences, Bangor University, 3rd floor ECW, Deiniol Road, Bangor, LL57 2UW, UK
- Captive & Field Herpetology Ltd, Wales, 13 Hirfron, Holyhead, Llaingoch, Anglesey, LL65 1YU, UK
| | - Cameron Wesley Hodges
- School of Biology, Institute of Science, Suranaree University of Technology, Muang Nakhon Ratchasima, Thailand
| | - Allwin Jesudasan
- Madras Crocodile Bank Trust, Centre for Herpetology, Post bag No.4, Vadanamelli Village, East Coast Road, Mamallapuram, 603 104, Tamil Nadu, India
| | - Gnaneswar Ch
- Madras Crocodile Bank Trust, Centre for Herpetology, Post bag No.4, Vadanamelli Village, East Coast Road, Mamallapuram, 603 104, Tamil Nadu, India
| | - Ajay Kartik
- Madras Crocodile Bank Trust, Centre for Herpetology, Post bag No.4, Vadanamelli Village, East Coast Road, Mamallapuram, 603 104, Tamil Nadu, India
| | - Peter Christopher
- Madras Crocodile Bank Trust, Centre for Herpetology, Post bag No.4, Vadanamelli Village, East Coast Road, Mamallapuram, 603 104, Tamil Nadu, India
| | | | - Hiral Naik
- School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Johannesburg. P. O. Wits, 2050, Gauteng, South Africa
- Save the Snakes, R527, Blyderus, Hoedspruit, 1380, South Africa
| | - Vishal Santra
- Captive & Field Herpetology Ltd, Wales, 13 Hirfron, Holyhead, Llaingoch, Anglesey, LL65 1YU, UK
- Society for Nature Conservation, Research and Community Engagement (CONCERN), Nalikul, Hooghly, West Bengal 712407, India
| | - Sourish Rajagopalan Kuttalam
- Society for Nature Conservation, Research and Community Engagement (CONCERN), Nalikul, Hooghly, West Bengal 712407, India
| | - Shaleen Attre
- Durrell Institute of Conservation and Ecology, School of Anthropology and Conservation, Marlowe Building, University of Kent, Canterbury, Kent, CT2 7NR, UK
| | - Mahmood Sasa
- Instituto Clodomiro Picado, Universidad de Costa Rica, San José, Costa Rica
- Escuela de Biología, Universidad de Costa Rica, San José, Costa Rica
| | - Carlos Bravo-Vega
- Research Group in Mathematical and Computational Biology (BIOMAC), Department of Biomedical Engineering, University of the Andes, Bogotá, Colombia
| | - Kris A. Murray
- MRC Centre for Global Infectious Disease Analysis, Imperial College London, UK
- MRC Unit The Gambia at London School of Hygiene and Tropical Medicine, Atlantic Boulevard, Fajara, Gambia
| |
Collapse
|
5
|
Harvey JA, Larsen KW. Rattlesnake migrations and the implications of thermal landscapes. MOVEMENT ECOLOGY 2020; 8:21. [PMID: 32514356 PMCID: PMC7251723 DOI: 10.1186/s40462-020-00202-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 03/24/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND The importance of thermal resources to terrestrial ectotherms has been well documented but less often considered in larger-scale analyses of habitat use and selection, such as those routinely conducted using standard habitat features such as vegetation and physical structure. Selection of habitat based on thermal attributes may be of particular importance for ectothermic species, especially in colder climates. In Canada, Western Rattlesnakes (Crotalus oreganus) reach their northern limits, with limited time to conduct annual migratory movements between hibernacula and summer habitat. We radio-tracked 35 male snakes departing from 10 different hibernacula. We examined coarse-scale differences in migratory movements across the region, and then compared the route of each snake with thermal landscapes and ruggedness GIS maps generated for different periods of the animals' active season. RESULTS We observed dichotomous habitat use (grasslands versus upland forests) throughout most of the species' northern range, reflected in different migratory movements of male snakes emanating from different hibernacula. Snakes utilizing higher-elevation forests moved further during the course of their annual migrations, and these snakes were more likely to use warmer areas of the landscape. CONCLUSION In addition to thermal benefits, advantages gained from selective migratory patterns may include prey availability and outbreeding. Testing these alternative hypotheses was beyond the scope of this study, and to collect the data to do so will require overcoming certain challenges. Still, insight into migratory differences between rattlesnake populations and the causal mechanism(s) of migrations will improve our ability to assess the implications of landscape change, management, and efficacy of conservation planning. Our findings suggest that such assessments may need to be tailored to individual dens and the migration strategies of their inhabitants. Additionally, local and landscape-scale migration patterns, as detected in this study, will have repercussions for snakes under climate-induced shifts in ecosystem boundaries and thermal regimes.
Collapse
Affiliation(s)
- Jessica A. Harvey
- Environmental Science Program, Thompson Rivers University, Kamloops, Canada
- Victoria, Canada
| | - Karl W. Larsen
- Department of Natural Resource Science, Thompson Rivers University, 805 TRU Way, Kamloops, British Columbia V2C 0C8 Canada
| |
Collapse
|
6
|
Maida JR, Bishop CA, Larsen KW. Migration and disturbance: impact of fencing and development on Western Rattlesnake (Crotalus oreganus) spring movements in British Columbia. CAN J ZOOL 2020. [DOI: 10.1139/cjz-2019-0110] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Due to increasing anthropogenic pressures, including land-use transformation globally, the natural process of animal migration is undergoing alterations across many taxa. Small-scale migrants provide useful systems at workable scales for investigating the influence of disturbance and landscape barriers on natural movement patterns and migrations. The Western Rattlesnake (Crotalus oreganus Holbrook, 1840) in British Columbia, Canada, is a small, migrant predator that undertakes seasonal spring movements from its communal hibernaculum to summer hunting and mating grounds and reverses its movements in autumn. From 2011 to 2016, we examined changes to spring migration movements in 27 male Western Rattlesnakes encountering both mitigative fencing barriers and disturbed habitats. Individuals moving through disturbed habitats or intercepted by mitigative fencing demonstrated shorter migration distances and reduced spring path sinuosity compared with individuals migrating in undisturbed habitats. Specifically, individuals encountering a fence during spring movements completed shorter total spring migration path lengths and occupied smaller home ranges over the course of the entire active season. Total spring migration distance also was strongly associated with the distance that individuals traveled until they first encountered human disturbance. This study contributes significantly to our knowledge of how fencing barriers may impact normal behavioural patterns in smaller vertebrates.
Collapse
Affiliation(s)
- Jared R. Maida
- Environmental Science Program, Thompson Rivers University, 805 TRU Way, Kamloops, BC V2C 0C8, Canada
| | - Christine A. Bishop
- Environment and Climate Change Canada, Science and Technology Branch, Wildlife Research Division, 5421 Robertson Road, Delta, BC V4K 3N2, Canada
| | - Karl W. Larsen
- Department of Natural Resource Science, Thompson Rivers University, 805 TRU Way, Kamloops, BC V2C 0C8, Canada
| |
Collapse
|
7
|
Lomas E, Maida JR, Bishop CA, Larsen KW. Movement Ecology of Northern Pacific Rattlesnakes (Crotalus o. oreganus) in Response to Disturbance. HERPETOLOGICA 2019. [DOI: 10.1655/d-17-00060] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Emily Lomas
- Environmental Science Program, Thompson Rivers University, 805 TRU Way, Kamloops, British Columbia V2C 0C8, Canada
| | - Jared R. Maida
- Environmental Science Program, Thompson Rivers University, 805 TRU Way, Kamloops, British Columbia V2C 0C8, Canada
| | - Christine A. Bishop
- Environment and Climate Change Canada, Science and Technology Branch, Wildlife Research Division, 5421 Robertson Road, Delta, British Columbia V4K 3N2, Canada
| | - Karl W. Larsen
- Department of Natural Resource Science, Thompson Rivers University, 805 TRU Way, Kamloops, British Columbia V2C 0C8, Canada
| |
Collapse
|