Published online January 14, 2022
Journal of Ecology and Environment (2022) 46:02
© The Ecological Society of Korea.
1Central Department of Botany, Tribhuvan University, Kathmandu 44613, Nepal
2Institute of Botany, The Czech Academy of Sciences, Z?mek 1, 252 43 Pr?honice, Czech Republic
3Global Change Research Institute, The Czech Academy of Sciences, B?lidla 986/4a, 603 00 Brno, Czech Republic
Correspondence to:Bharat Babu Shrestha
Jyoti Khatri-Chettri’s current affiliation is Trichandra Multiple Campus, Tribhuvan University, Kathmandu, Nepal.
This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
Background: Parthenium hysterophorus L. (Asteraceae; hereafter Parthenium) is an invasive alien species of global significance because of its’ negative ecological and socioeconomic impacts. This species is spreading rapidly from lowland Tarai to Middle Mountain regions in Nepal. In the present study, we analyzed the impacts of Parthenium on plant community composition including their soil seedbank in subtropical grasslands located in central Nepal. Data was collected in a 10 m long transects passing through areas of high (> 90% cover), medium (40%-60%) and low (< 10%) levels of Parthenium cover using a plot of 1 m2. Altogether, we sampled 90 plots in 30 transects. Seedling emergence method was used to estimate soil seedbank density in the soil samples (0-10 cm depth) collected from the plots with high Parthenium cover.
Results: There was no significant difference in the plant species richness at different levels of Parthenium invasion whereas there was a significant change in the species composition of above ground flora due to Parthenium invasion. There was also a significant difference in species composition between soil seedbank and aboveground flora in the highly invaded plots. Parthenium was the most dominant in soil seedbank, contributing 65% to the total soil seedbank.
Conclusions: Our study suggests that Parthenium has considerable negative impact on the native grassland flora, and the dominance of Parthenium in the soil seedbank means there is a challenge for its management. It also suggests the need of monitoring the soil seedbank dynamics while managing Parthenium weed.
Keywords: grassland, germinable soil seedbank, species composition, Parthenium hysterophorus
Increasing invasions by alien plants in grasslands and subsequent alteration of species composition and ecological processes is a global problem, particularly in the grasslands of human dominated landscapes (Cilliers et al. 2008; Seastedt and Pyšek 2011). Annual invasive weed
Previous studies in Nepal have revealed that
The study area is located in the Siwalik region of Makawanpur district in south-central Nepal (Fig. 1). Geologically, the Siwalik region represents Sub-Himalayan zone (southernmost front of Himalaya
The sampling sites are located in Hetaunda Municipality which is the district headquarter and the most populated and urbanized city of Makawanpur district. The sampling sites (27° 25’ N latitude, 85° 03’ E longitude, 450–490 m asl elevation) were the grasslands located in the property of Hetaunda Cement Factory (two of the three sites) and Hetaunda Industrial Area (one of three sites) (Fig. 1). The grassland had been grazed throughout the year by domestic animals, and fodder collection activities were high during the summer. These sites were also subjected to frequent sport activities during winter months.
The vegetation sampling was carried out during late monsoon season (September) along 30 transects of about 10 m long with 10 transects at each of the three sites. Along each transect, three plots of 1 m × 1 m were sampled in such a way that they represented > 90%, > 40% to ≤ 60% and < 10% cover of
Soil samples were collected after one month of vegetation sampling (i.e., October) when most of the plants including
Seedling emergence method was used to assess the germinable soil seedbank (Simpson 1989). This method has been also used previously for the study of soil seedbank of
Specimens of all plant species encountered during vegetation sampling as well as those grown in green house, were collected, tagged, dried and then mounted on the herbarium sheets. They were identified with the help of local flora (e.g., Siwakoti and Varma 1999) and by comparing with the specimens housed at Tribhuvan University Central Herbarium (TUCH), Kirtipur and National Herbarium and Plant Laboratories (KATH), Godawari. We followed Roskov et al. (2019) for the nomenclature.
Community and population attributes recorded in plots with different intensity of
Germinable soil seedbank density (seeds/m2) of
Multivariate tests were used for plant species composition in plots with different levels of
We recorded a total of 62 plant species including
The species composition in plots with different levels of
We recorded a total of 46 species in soil seedbank (Additional file 1: Table S2); 42 species were from top layer (0–5 cm depth) and 25 species were from deeper layer (5–10 cm depth). Jaccard’s and Sorensen’s Similarity Indices between standing (above ground) flora in the plots having high levels of
The composition of associated plants varied significantly (
Our study showed that
There was no significant difference in species richness among plots of different levels of
There was very low species similarity (Jaccard’s Similarity Index being 19% and Sorensen’s similarity index being 32%) between standing flora (above ground) and soil seedbank (below ground) flora. Our result is in line with Looney and Gibson (1995) who showed the value for Jaccard’s Similarity Index to be 36% between standing flora and soil seedbank in coastal barrier island of Florida, the USA. We found significant difference in the species composition of above ground flora and soil seedbank. Such differences are also reported earlier (e.g., Ayele et al. 2013; Török et al. 2009). Ayele et al. (2013) compared the vegetation composition between the standing flora and soil seedbank flora in the plots with different levels of
Beside the allelopathic effect of
A typical mature plant of
Most of the germinable seeds of
In a grassland subjected to livestock grazing, we showed that
Supplementary information accompanies this paper at https://doi.org/10.5141/jee.21.00083.
Additional file 1: Table S1. List of plant species recorded in above ground vegetation in the sample plots. Table S2. List of plant species at two different soil depths (0–5 cm and 5–10 cm) recorded during the soil seedbank study.
We are thankful to Ambika Paudel for help in field data collection and laboratory works, and Mahesh Bisht for preparing map of the study area. We are also thankful to Tribhuvan University Central Herbarium (TUCH) and National Herbarium and Plant Laboratories (KATH) for their permission to examine herbarium specimens for plant identification.
CCA: Canonical Correspondence Analysis
KATH: National Herbarium and Plant Laboratories, Nepal
SPSS: Statistical Package for Social Sciences
TUCH: Tribhuvan University Central Herbarium, Nepal
BBS conceptualized the research and did experimental design. JKC and BBS collected field and laboratory data. MBR and JKC analyzed data. JKC prepared first draft of the manuscript. BBS, MBR and JKC revised and finalized the manuscript.
JKC, MSc, is an Assistant Professor at Botany Department, Trichandra Multiple Campus, Tribhuvan University, Kathmandu, Nepal. She has completed her two years master’s degree in Botany (specialization is ecology). She has research interests in invasion ecology, soil seedbank study, plant allelopathy, and plant ecophysiology.
MBR, PhD, is a research fellow at Czech Academy of Sciences (Institute of Botany and Global Change Research Institute). His research interests are on biological invasions, economically important plants and spatial ecology mainly along elevational gradients in Himalayan region.
BBS, PhD, is an Associate Professor at the Central Department of Botany, Tribhuvan University, Kathmandu, Nepal, with research interests on biological invasions, forest ecology, and plant adaptation along environmental gradients in mountains. He is currently involved as Lead Author in thematic Assessment on Invasive Alien Species which is being commissioned by the Intergovernmental Science-Policy Platform for Biodiversity and Ecosystem Services (IPBES).
Field and laboratory works were supported by a grant from Nepal Academy of Science and Technology (NAST) to BBS. Partial financial support was also received by JKC from Cornell Nepal Student Programm (CNSP), Kirtipur, Nepal. MBR is partly supported by long-term research development project No. RVO 67985939 of the Czech Academy of Sciences and institutional support for science and research of the Ministry of Education, Youth and Sports of the Czech Republic.
The datasets supporting the conclusions of this article are included within the article (and its additional files).
The authors declare that they have no competing interests.