Maritime international trade and bioinvasions: a three-year long survey of small mammals in Autonomous Port of Cotonou, Benin
Data files
Nov 07, 2023 version files 4.15 MB
Abstract
- International trade has been favoring the dissemination of a wide panel of invasive alien species. Upstream prevention through the monitoring of entry points is identified as an appropriate strategy to achieve control of bioinvasions and their consequences. Maritime transports have been responsible for the introduction worldwide of exotic rodents that are major pests for crops and food stocks as well as reservoirs of many zoonotic pathogens. In order to limit further dissemination, the International Health Regulation constrains decision makers and socio-economic stakeholders to manage ship-mediated import/export of rodents within seaports. Unfortunately, eco-evolutionary insights into rodent introduction events that could guide preventive actions in seaports are very scarce.
- In order to bridge this gap, we here describe the results of a three-year-long survey of small mammals conducted in the Port of Cotonou, Benin, that aims at assessing the spatio-temporal distribution, diversity and relative abundance of invasive and native rodents.
- 960 small mammal individuals were captured in nine within-seaport sites. We found (i) a marked predominance of invasive species (84% of the individuals belonging to Mus musculus, Rattus rattus, R. norvegicus), (ii) with native species (i.e., Mastomys natalensis and the shrew Crocidura olivieri) essentially restricted to peripheral non-industrial areas, as well as (iii) a fine-scale spatial segregation stable over time between the invasive Norway rats and house mice on the one hand, and the black rats and shrews on the other hand.
- Furthermore, trapping before and after two successive rodent anticoagulant-based control campaigns indicates that they were poorly efficient and that subsequent rodent recolonization occurs 6–12 months following intervention.
- Synthesis and applications: Our results are discussed in terms of ecological processes at play (e.g., interspecific interactions) and operational actions that may be implemented to improve rodent control (e.g., assessment of proper eradication units, environmental modifications) and to limit re-infestation (e.g., rat-proofing of moors and buildings).
README: Maritime international trade and bioinvasions: a three-year long survey of small mammals in Autonomous Port of Cotonou, Benin
[https://doi.org/10.5061/dryad.bg79cnph4]
In this study of three years of monitoring, we assessed the spatio-temporal distribution, diversity and relative abundance of invasive and native rodents in a West African autonomous port. Data useful for interpreting the results were collected during each sampling campaign at each of the surveyed sites.
Details for each dataset are provided in the README file.
Datasets included:
- Small mammal captures by wire and shermans traps. Number of small mammals caught per trapping campaign.
- Sampling design. Description of the characteristics of each sampled site.
- Trapping and identification of small mammals Sampling protocol in detail. Morphological identification using morphometric measurements (body mass, length of body, tail, hind leg and ear).
- Trapping data analysis Trap-specific and species-specific trapping effort under the R software (R Core Team, 2011). Species-specific relative abundance according under the R software (R Core Team, 2011). Specific diversity using EstimateS v.9.1.0. Co-occurrence analyses using the program Pairs v.1.0. Occupancy modelling under R using the unmarked v.0.13-2 package.
There are not missing values.
Supplementaries are available in the README file.
Supplementary 1 Sampling sites in the port, their descriptions and GPS coordinates
Supplementary 2 Distribution of the number of captures according to sessions, sites and trap type for each species
Supplementary 3 Proportion of each type of trap (wire and sherman) set at the nine sites during sessions
Supplementary 4 Comparison of the two types of traps in APC3
Supplementary 5 Species-specific success for Rattus rattus in APC1 and APC2
Supplementary 6 Species diversity in the artisanal (APC1-2) vs the industrial seaport (APC3-9)
Supplementary 7 Detection probabilities as a function of sessions and trap types at sites for each species
Supplementary 8 Model comparison procedure for all species and datasets to detection and occupancy probabilities
A) Organized by File type
DatasetA
I- Data/
- Data used for analyses and overall raw sampling data I I- Processed/ Data used for analyses. I I 1- Co occurence
- Excel spreadsheet of the 960 small mammals captured per sampling site per session, by species.
- Excel spreadsheet of 849 small mammals captured per sampling site per session, according to species with numbers greater than or equal to 10.
- These analyses were performed using Pairs v.1.0 software with a 95% confidence interval. I I 2- Occupancy modelling
- Encoded spreadsheets for calculating the probability of detection and occupancy of captures from 3 nights of trapping for each locality, by session and by trap type for Crocidura olivieri, R. rattus, R. norvegicus and Mus musculus. (N1, N2 et N3 : 1=capture, 0=no capture, Blank cell=no trap set at this location ; loc : 1=APC1, 2=APC2, 3=APC3, 4=APC4, 5=APC5, 6=APC6, 7=APC7, 8=APC8 ; Trap: 1=sherman, 0=Wire ; n1=night1, 2=night2 and 3=night3).
- The analysis was performed under R using the unmarked v.0.13-2 package. I I 3- Specific diversity
- Excel spreadsheet for estimating the specific diversity of the number of captures of Rattus rattus, Rattus norvegicus, Mus musuclus, Mastomys natalensis and Crocidura sp per session in APC1-2 : artisanal seaport versus AP3-9 : industrial seaport
- The analysis was performed on EstimateS v.9.1.0 I I 4- Statistical data
- APC-Traps (data original) : Encoded spreadsheet of the 3 nights' trapping catches for each locality, by session and by trap type.
- APC1-Traps to APC 9-Traps : Encoded spreadsheet of catches for the 3 nights of trapping by session and by trap type for APC1 to APC9
- tAPC1-species to tAPC9-species : Excel spreadsheet to calculate the relative abundance of each site according to species caught, session and trap type for APC1 to APC9 for the most abundant species.
- tAPC8-Rn-Mus : Excel spreadsheet to calculate the relative abundance in APC8 between Rattus norvegicus and Mus musculus per session and trap type.
- tAPC8-Rn-Rr : Excel spreadsheet to calculate the relative abundance in APC8 between Rattus norvegicus and Rattus rattus per session and trap type.
- tAPC8-Rr-Mus : Excel spreadsheet to calculate the relative abundance in APC8 between Rattus rattus and Mus musculus per session and trap type.
- APC3-Proportion of traps per sessions : APC 3 Only site with a significant difference between the numbers of each type of trap set per session
- Database : Database of small mammals captured by collection number, species, session, trap type, locality and sites.
- Script-SB : Script for comparison of trapping yields between species, comparison of relative abundance between species and comparison of trapping effort between sessions
- Traps by sessions : Encoded excel spreadsheet of the number of traps set during the 3 nights of trapping for each location and session
- All analyses were performed under the R software (R Core Team, 2011) and p-values<0.05 were considered significant. I I- Raw Overall raw sampling data. I I 1- APC trapping report
- Raw data : Excel spreadsheet organizing the raw data from the 6 sampling sessions for each site, according to the number of each type of trap set, the total number of mammals captured according to each trap type, the number of individuals captured per species according to trap type.
- APC1-9 : Excel spreadsheet organizing sampling data from nine sites (APC1-9) according to species captured per session and trap type.
- R norvegicus : Excel spreadsheet summarizing captures of R norvegicus at each site according to the number of traps set and the number of captures according to trap type.
- R rattus : Excel spreadsheet summarizing captures of R rattus at each site according to the number of traps set and the number of captures according to trap type.
- M musculus: Excel spreadsheet summarizing captures of Mus musculus at each site according to the number of traps set and the number of captures according to trap type.
- Crocidura sp : Excel spreadsheet summarizing captures of Crocidura at each site according to the number of traps set and the number of captures according to trap type.
- Mastomys natalensis : Excel spreadsheet summarizing captures of Mastomys natalensis at each site according to the number of traps set and the number of captures according to trap type.
- All species depending on sites : Excel spreadsheet summarizing all species captured by site and trap type.
- All species function atime : Excel spreadsheet summarizing all species captured by session. I I 2- Small mammal abundance in APC
- Excel spreadsheet classifying each species according to its status (invasive or native) based on sites, geographical coordinates, number of traps set and capture rates for each species. I I 3- Trapping sites Figure : A) Assemblage of traditional stores (APC1), B) fresh fish market (APC2), c) restaurants and outdoor canteens (APC3), D) four large non-joined industrial storehouses (APC4-7), E) garage and mechanical equipment storage rooms (APC8) and F) storage area for large equipment (APC9). I I 4- Trapping yields
- Excel spreadsheet of capture yields for different species at each site, by session and by trap type. A) Organized by Analysis DatasetB I- Results I 1- Statistical analyses
- Comparisons of wire vs sherman trapping yields ("Chi-squared") for all sessions and all sites by species.
- Comparisons of wire vs sherman trapping yields ("Chi-squared") all sessions per site.
- Calculate of the relative abundance probability between species at each sampling site. I 2- Wilcoxon analyses
- Pairwise comparisons using Wilcoxon rank sum test for each species I 3- Yields R norvegicus - R rattus - Mus musculus
- Yields for R norvegicus in APC4-8 captured by the wire, Mus musculus in APC4-8 captured by the shermans and R rattus captured by the wire and shermans in APC1, 2 and 8.
Methods
1- Sampling design,
2- Trapping and identification of small mammals,
3- Trapping data analysis (Trap-specific and species-specific trapping effort, Species-specific relative abundance according, Specific diversity, Co-occurrence analyses, Occupancy modelling)