Ecological Research

  • STATISTICS

    Vol. 32 (2017)
    No. submitted articles: 536
    No. accepted articles: 126

    stat

    Current issue
    (vol. 33, issue 2)
    Days for acceptance:
    213 (81–425)
    Days for online-first:
    226 (93–409)
    Days for publication:
    290 (141–439)

The 16th ECOLOGICAL RESEARCH AWARD

    
  • Biogeochemical nitrogen properties of forest soils in the Japanese archipelago

    Rieko Urakawa, Nobuhito Ohte, Hideaki Shibata, Ryunosuke Tateno, Takuo Hishi, Keitaro Fukushima, Yoshiyuki Inagaki, Keizo Hirai, Tomoki Oda, Nobuhiro Oyanagi, Makoto Nakata, Hiroto Toda, Tanaka Kenta, Karibu Fukuzawa, Tsunehiro Watanabe, Naoko Tokuchi, Tatsuro Nakaji, Nobuko Saigusa, Yukio Yamao, Asami Nakanishi, Tsutomu Enoki, Shin Ugawa, Atsushi Hayakawa, Ayumi Kotani, Megumi Kuroiwa, Kazuo Isobe

    Ecological Research vol.30, No. 1 pp. 1–2

    Keywords: Gross nitrogen transformation rate; Litter layer stock; Net nitrogen transformation rate; Nitrification; Nitrogen cycle; Nitrogen mineralization; The Japanese archipelago; Total carbon and nitrogen concentrations; Water-soluble ions; Water-soluble organic carbon

    Abstract This data paper provides some biogeochemical nitrogen (N) properties and related chemical properties of forest soils from 39 sites throughout the Japanese archipelago. The data set was collected and analyzed under the GRENE (Green Network of Excellence) environmental information project and the ReSIN (Regional and comparative Soil Incubation study on Nitrogen dynamics in forest ecosystems) project. The sites cover 44°20”N to 26°50’N and the climate ranges from cool-temperate zone to subtropical zone. At each site, litter on forest floor and soil samples (three or four layers to 50 cm depth) were collected between August and November in 2010–2013 from five soil profiles. From the litter layer samples, the stocks and concentrations of total carbon (C) and N were measured. From the mineral soil samples, bulk density, pH (H2O), total C and N concentrations, net and gross rates of N mineralization, nitrification and concentrations of water-soluble substances were measured. The measurements are relevant for other biogeochemical N studies in forest ecosystems and the data set provides basic information on the N pool and fluxes with related chemical properties of forest soils across the Japanese archipelago. The average rates of net and gross N transformation at 20 °C across the sites were 0.26 ± 0.47 mgN kg-1 soil d-1 for net N mineralization, 0.25 ± 0.45 mgN kg-1 soil d-1 for net nitrification, 4.06 ± 0.47 mgN kg-1 soil d-1 for gross N mineralization, and 1.03 ± 1.29 mgN kg-1 soil d-1 for gross nitrification (average ± SD).

  • Antifungal activity of a termite queen pheromone against egg-mimicking termite ball fungi

    Kenji Matsuura, Takeshi Matsunaga

    Ecological Research vol.30, No. 1 pp. 93–100

    Keywords: Queen pheromone; Termite ball; Semiochemical parsimony; Insect-fungal interaction; Antimicrobial compounds

    Abstract The sophisticated colony organization of eusocial insects is attributed to their elaborate chemical communication systems. Pheromones mediate most behaviors involved in colony organization including foraging, defense, brood care, and caste regulation. The number of candidate compounds available to regulate multiple systems may be biosynthetically finite and the production of several compounds instead of a single one may be more costly. Therefore, strong selection pressures encourage the use of single natural products for many purposes. Such versatility of signal substances is especially characteristic of queen pheromones in eusocial Hymenoptera. However, little is known about the multifunctionality of the recently identified termite queen pheromone. Here, we demonstrate that volatile compounds in the queen pheromone of a termite, Reticulitermes speratus (Kolbe), have fungistatic properties. Application of the pheromone compounds n-butyl-n-butyrate and 2-methyl-1-butanol significantly reduced the germination rates of the egg-mimicking parasitic termite ball fungus. These pheromone compounds also suppressed mycelial growth of the termite ball fungus and some entomopathogenic fungi. However, the inhibitory activity of each substance differed among fungal strains. Termites likely employ these antimicrobial volatiles to protect eggs and queens, and secondarily as communication agents informing queen fertility. This study supports the notion of evolutionary parsimony, wherein pheromones are originally used as defensive compounds and their communicative function develops secondarily, which is well-documented in social Hymenoptera.

  • Relationships among plant genetics, phytochemistry and herbivory patterns in Quercus castanea across a fragmented landscape

    Yurixhi Maldonado-Lopez, Pablo Cuevas-Reyes, Antonio Gonzalez-Rodriguez , Griselda Perez-Lopez, Carlos Acosta-Gomez, Ken Oyama

    Ecological Research vol.30, No. 1 pp. 133–143

    Keywords: Folivores; Leaf miners; Mexico; Microsatellites; Oak

    Abstract Herbivorous insects respond to the chemical variation of their host plants which, in turn, usually has a genetic component. Therefore, it is expected that individual host plants with similar genotypes will have similar secondary chemistries and herbivore communities. However, natural or anthropogenic environmental variation can also influence secondary chemistry and herbivore abundance and composition. Here, we determined the relationships among plant genetics, phytochemistry, and herbivory levels by leaf chewers and miners in the red oak Quercus castanea, across a fragmented landscape. Ten oak individuals were sampled at each of four sites in the Cuitzeo basin, central Mexico. Two sites were small and fragmented forest patches and two were large and continuous patches. Individuals were genotyped with six nuclear microsatellites, and analyzed chemically to determine foliar concentrations of water, total nonstructural carbohydrates, and secondary compounds. Damage by leaf chewers was higher in the small fragments than in the large fragments. Mantel tests indicated significant correlations of the genetic distance among individuals with their chemical similitude, and also of chemical similitude with damage levels by leaf miners, but not with damage by folivores. There was no direct relationship between genetic distance and herbivory levels by any of the two insect guilds. Our results suggest that variation in concentration of secondary metabolites in Q. castanea has a genetic component and that plant chemistry acts as an intermediate link between plant genes and the community of associated herbivores. However, this effect was only apparent for herbivory by leaf miners, probably because these insects interact more intimately with the host, while free-living leaf chewers may be more responsive to environmental variation.

  • Capitulum and rosette leaf avoidance from grazing by large herbivores in Taraxacum

    Noboru Fujita, Ryosuke Koda

    Ecological Research vol.30, No. 3 pp. 517–525

    Keywords: Scape; Livestock; Pasture; Rural habitat; Urban habitat

    Abstract Plants defense against herbivore damage is achieved through resistance and tolerance, of which resistance is composed of avoidance and antibiosis. Plants have developed various adaptations that facilitate escape from herbivory. We hypothesized that post-anthesis prostrate scapes in Taraxacum is an adaptation for avoidance of capitulum grazing by large herbivores. To test this hypothesis, we divided flowering into the following four stages based on the external appearance of the capitulum: green bud, yellow corolla, brown corolla, and white pappus stages. We conducted an experiment in natural pasture in Mongolia to artificially raise capitula and rosette leaves of T. collinum. We measured the natural height of capitula and rosette leaves of the Mongolian pasture and urban species, T. collinum and T. ceratophorum, respectively, and of the Japanese rural and exotic urban species, T. japonicum and T. officinale, respectively. We investigated natural grazing by livestock in the field of the capitula and rosette leaves of the two Mongolian species. In Mongolia, naturally short capitula at the green bud and brown corolla stages and rosette leaves of T. collinum were not grazed. However, artificially raised capitula and rosette leaves of T. collinum and the naturally high capitula and leaves of T. ceratophorum were grazed. Short capitulum and leaf height was shown to be effective for avoidance of livestock grazing in Mongolia. In Japan, T. japonicum and T. officinale showed similar scape behavior to T. collinum and T. ceratophorum, respectively. We discuss the reasons for the capitulum behavior differences in Japan.

  • Variation in microbial function through soil depth profiles in the Kushiro Wetland, northeastern Hokkaido, Japan

    Yukiko Senga, Mikiya Hiroki, Shigeharu Terui, Seiichi Nohara

    Ecological Research vol.30, No. 4 pp. 563–572

    Keywords: Soil microbial function; Decomposition; Phosphate production; Denitrification; Wetland

    Abstract To provide new insights into microbial functions in the Kushiro Wetland, Japan, we measured vertical profiles of fluorescein diacetate hydrolysis (total microbial activity), β-glucosidase and xylosidase (organic matter decomposition), acid phosphatase (phosphate production) and potential denitrifying (denitrification) activities as microbial enzyme activities in soil to depths of approximately 1.5 m from two sites with different vegetation in November 2008 (winter) and August 2009 (summer). Active organic matter decomposition, phosphate production and denitrification were evident in shallow litter and peat layers, and total microbial activity was high. Almost no differences in decomposition and total microbial activity were observed between seasons, whereas phosphate production and denitrification were higher in summer. All activities were low in mid-depth volcanic-ash and clay layers because of low carbon, nitrogen and phosphorus levels. Surprisingly, the total microbial activity and decomposition in deep clay & peat and peat layers were the same as or higher than in shallow layers. However, denitrification was limited, probably because dissolved organic matter containing humic-like substances was unsuitable as a substrate. Moreover, total soil phosphorus levels, acid phosphatase activity and multiple linear regression analysis revealed that the soil in the Kushiro Wetland is likely P limited.