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Corresponding author: Shigenori Karasawa ( dojyoudoubutu@gmail.com ) Academic editor: Katalin Szlavecz
© 2018 Takahiro Nasu, Kana Kitagawa, Shigenori Karasawa.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Nasu T, Kitagawa K, Karasawa S (2018) Species compositions of terrestrial isopods in public parks of a commuter town in Japan. In: Hornung E, Taiti S, Szlavecz K (Eds) Isopods in a Changing World. ZooKeys 801: 389-399. https://doi.org/10.3897/zookeys.801.21875
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The species compositions of terrestrial isopod assemblages in 150 public parks in a commuter town in Japan were investigated. Eleven species of terrestrial isopods were present, of which seven were considered native or oriental species, and four were exotic species originally distributed in the Mediterranean and European regions. An exotic species Armadillidium vulgare Latreille, 1804 was found in all parks. Logistic model analysis indicated that the surrounding land use affected the distributions of three native species, Burmoniscus kathmandius (Schmalfuss, 1983), Ligidium koreanum Flasarova, 1972, and Mongoloniscus koreanus Verhoeff, 1930, indicating that landscape properties are important factors that limit the distributions of terrestrial isopods. The present study also showed that the public parks surrounded by forests or semi-natural environments in a commuter town provide habitats for native terrestrial isopods.
GIS, GLM, landscape environments, local environments, logistic distributions
Urbanization has rapidly spread throughout the world and has changed species compositions of regions through decreased diversity of native species (
The Mediterranean region is considered a hotspot of terrestrial isopod diversity (
The aims of this study were: 1) to describe the terrestrial isopod fauna in public parks of a commuter town in Japan; 2) to evaluate environments that limit species distributions; and 3) to determine whether public parks in the town provide habitats for native terrestrial isopods.
One hundred fifty public parks were selected in Munakata City, Fukuoka, Japan (Figure
Location of Munakata city (red circle in the top right map) and map of the study area. Yellow circles represent sampling sites (parks). Blue denotes rice paddy; red denotes residential region; pink denotes grass; green denotes forest; the white line is Japan National Route 3. The map was created by modifying the high resolution land-use and land-cover map ver16.02 (http://www.eorc.jaxa.jp/ALOS/lulc/jlulc_jpn.htm).
Environmental variables were recorded at two levels: local and landscape scales. For local environments, the presence or absence of flower beds and woods in the parks were recorded during sampling. In addition, the percentage of the area of grass in parks was estimated using Google Map (https://www.google.co.jp/maps). For landscape environments, the areas of land use around the parks were measured using geographical information system (GIS) data. A raster data set for a high-resolution land-use and land-cover map (ver. 16.02) was obtained from the advanced land-observing satellite (http://www.eorc.jaxa.jp/ALOS/lulc/jlulc_jpn.htm;
To evaluate the appropriate areas to use for the landscape environments, the Akaike information criteria (AIC) of the generalized linear models (GLMs) were compared at the five buffer widths for each species. The GLM was also used to evaluate relationships between the presence of 10 species and the species richness of native and exotic species (as response variables) with respect to environmental variables (as explanatory variables). Logistic (binary) and Poisson distributions were applied to the response variables of presence and species richness (of native and exotic species), respectively. Environmental variables were composed of three local variables (area percentage of grass, presence of flower beds and woods), and four landscape variables (areas of rice paddy, residential region, grass and forest). Using this procedure, perfect or quasi-perfect separations were found in the logistic models for some species. Thus, Firth’s bias-reduced logistic regression (
A total of 17 isopod species was recorded in the city, eleven of which were collected in the public parks. Five species, A. vulgare, Haplophthalmus danicus Budde-Lund, 1880, Porcellio laevis Latreille, 1804, P. scaber Latreille, 1804 and Porcellionides pruinosus (Brandt, 1833), are exotic species in Japan (
Species, numbers of individuals collected and collection sites in the urban parks, glassland and forest in Munakata City, Japan.
Species | Urban park | Grasslanda | Forest | |
---|---|---|---|---|
No. of ind. | Sites | No. of ind. | No. of ind. | |
Native species | ||||
Agnara pannuosa | 18 | 9 | a fewb | 1089 |
Armadillidae sp. 1c | 9 | 5 | – | 1955 |
Armadillidae sp. 2 | – | – | – | 60 |
Armadillidae sp. 3 | – | – | – | 1 |
Burmoniscus dasystylus | – | – | – | 52 |
Burmoniscus kathmandius | 17 | 5 | – | – |
Exalloniscus cortii | – | – | – | 1 |
Ligidium koreanum | 8 | 3 | – | 683 |
Lucasioides spp. | 15 | 8 | – | 853 |
Mongoloniscus koreanus | 172 | 36 | 3781 | 2 |
Mongoloniscus vannamei | 110 | 36 | a few | 13 |
Mongoloniscus sp. | – | – | a few | – |
Exotic species | ||||
Armadillidium vulgare d | 372 | 150 | 4526 | 2220 |
Haplophthalmus danicus | – | – | – | 1 |
Porcellio laevis | 60 | 34 | – | – |
Porcellio scaber | 264 | 26 | – | 21 |
Porcellionides pruinosus | 51 | 10 | – | 1 |
Values of Moran’s I revealed that distribution of P. scaber showed significant spatial autocorrelation (I = 0.027, p < 0.05), while other species and species richness showed no significant spatial autocorrelation. There were differences among species in the spatial scales having the lowest AIC values: A. pannuosa, 25 m; Armadillidae sp. 1, 25 m; B. kathmandius (Schmalfuss, 1983), 50 m; L. koreanum, 500 m; Lucasioides spp., 250 m; M. koreanus, 100 m; M. vannamei, 250 m; P. laevis, 50 m; P. scaber, 500 m; P. pruinosus, 25 m (Supplementary material
Coefficients of explanatory variables and p values of the Likelihood ratio test.
Species | Local environments | Landscape environments | Intercept | Likelihood ratio test p–value | |||||
---|---|---|---|---|---|---|---|---|---|
Grass | Flower bed | Wood | Residential | Rice paddy | Grass | Forest | |||
Agnara pannuosa | 0.181 | 1.493 | -0.634 | -0.105 | -0.083 | – | 0.074 | -2.098 | 0.177 |
Armadillidae sp. 1 | 1.756 | -0.026 | -1.340 | – | -0.068 | 0.027 | 0.194 | -3.114 | 0.399 |
Burmoniscus kathmandius | 18.912 | -0.472 | 0.745 | -0.047 | -0.036 | – | -0.011 | -18.440 | 0.045 |
Ligidium koreanum | -2.809 | -1.331 | -1.137 | -0.001 | -0.001 | 0.0001 | – | 4.447 | 0.048 |
Lucasioides spp. | -0.210 | -1.906 | 0.148 | – | 0.001 | 0.001 | -0.002 | -2.262 | 0.015 |
Mongoloniscus koreanus | -0.035 | -0.031 | 0.063 | – | 0.009 | 0.012 | 0.011 | -3.367 | 0.00001 |
Mongoloniscus vannamei | 0.893 | 1.103 | -0.729 | – | -0.001 | 0.001 | -0.0002 | -1.919 | 0.243 |
Porcellio laevis | -0.010 | 0.250 | 0.632 | – | -0.010 | -0.018 | -0.036 | -1.222 | 0.158 |
Porcellio scaber | 1.200 | 0.452 | 0.398 | – | -0.0004 | 0.0000001 | -0.00002 | -2.296 | 0.272 |
Porcellionides pruinosus | 0.102 | -0.636 | 0.961 | -0.079 | 0.032 | – | -0.150 | -2.481 | 0.395 |
Number of species | |||||||||
Native species | 0.374 | 0.061 | 0.109 | – | 0.002 | 0.006 | 0.004 | -1.647 | 0.0002 |
Exotic species | 0.107 | 0.079 | 0.327 | – | -0.0001 | -0.001 | -0.001 | 0.002 | 0.906 |
The species compositions in patchily distributed areas such as parks are known to be affected by local environments within the areas and by landscape environments around the parks (
Four exotic species with original distributions in the Mediterranean and European regions (
Eleven terrestrial isopod species were found in the urban parks of a commuter town. Native species tended to be distributed in the parks located adjacent to natural environments, while their distributions had little relationship with the local environments within the parks. It is proposed that the location of parks is an important factor to consider in their design to protect the largest number of species of native terrestrial isopods.
We thank members of the Laboratory of Animal Ecology at Fukuoka University of Education for assistance with field surveys, and Dr. Takahito Kuroki for advices on GIS. We also thank the reviewers for their significant comments and efforts towards improving our manuscript. This work was supported by a Grant-in-Aid for Young Scientists (B) Grant Number 26830145. We thank Harry Taylor, PhD, from Edanz Group (www.edanzediting.com/ac) for editing a draft of this manuscript.
AIC values of GLMs at the five apatial scales