Volume 15, Issue 2 (10-2024)
J Watershed Manage Res 2024, 15(2): 154-168 |
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Faraji A, Tatian M, Tamartash R, Sanaei A. (2024). The Effects of Livestock Grazing on Species Diversity and Functional Indicators of Vegetation in Two Watersheds with Different Climates. J Watershed Manage Res. 15(2), 154-168. doi:10.61186/jwmr.15.2.154
URL: http://jwmr.sanru.ac.ir/article-1-1242-en.html
URL: http://jwmr.sanru.ac.ir/article-1-1242-en.html
1- Department of Range Science and Engineering, Sari Agricultural Science and Natural Resources University, Sari, Iran
2- Department of Range Science and Engineering, Sari Agricultural Sciences and Natural Resources University, Sari, Iran
3- Institute of Biology, Faculty of Life Sciences, Leipzig University, Germany
2- Department of Range Science and Engineering, Sari Agricultural Sciences and Natural Resources University, Sari, Iran
3- Institute of Biology, Faculty of Life Sciences, Leipzig University, Germany
Abstract: (202 Views)
Extended Abstract
Background: Decreasing or increasing diversity affects a community’s sustainability because biodiversity in any living community determines its specific function, and on the other hand, sustainability is considered the ability of an ecosystem to preserve and maintain its function. At the same time as the global threats of climate change and the increase in harvesting intensity in the last few decades, ecosystem functions have been the focus of many researchers. Due to the impact of biodiversity on the protection of different ecosystem functions, many studies have investigated biodiversity indicators and ecosystem functions in different environmental conditions. In the present study, species diversity (richness, Shannon-Wiener, Simpson, and evenness) and functional (functional richness, functional evenness, functional divergence, and CWM indices) indices were used to investigate their relationships with different grazing managements (light and heavy) and two different climates in the basins of Mazandaran province. This research aims to determine the role of variables influencing plant diversity and the pasture ecosystem functioning to help better manage summer pastures that play a protective role for downstream areas in watersheds.
Methods: The effects of livestock grazing were investigated on the diversity of two selected watersheds, Zaremrood and Cheshmehkileh, in the east and west of Mazandaran province. After determining plant types in each of the areas, light and heavy grazing sites were determined based on the accessibility and distance to sources, such as livestock husbandry, watering places, and roads. For sampling in the sites, the northern slopes with the same slope (0-20%) were selected to ensure homogeneity. Sampling was done using five main plots (10 × 10 m) so that three plots (1 × 1 m2) were within each plot. Thus, a total of 15 plots were used in each grazing site (light and heavy), and a total of 30 plots were used in the random-systematic design. To measure functional diversity indicators, the easily measurable functional characteristics of plants related to the level of ecosystem functioning were selected and measured in addition to species abundance data. Based on experts, opinions and a review of available sources, five traits (leaf area, leaf dry matter content, leaf specific area index, plant height, and leaf dry weight) were used to determine functional diversity. Species diversity indices were calculated in PAST software by calculating three indices of species diversity, including species richness, Shannon-Wiener diversity, and Simpson diversity. Data were statistically compared using the analysis of variance (ANOVA) in the form of the general linear model (GLM) and principal component analysis (PCA) to separate the grazing regions that can be separated using functional diversity indices.
Results: The dependent variables (weighted average of leaf area and dry matter content) were significantly different in various climates and different livestock grazing patterns. Similarly, the independent variables (area and livestock grazing) were significantly different from the variables of species richness, Shannon-Wiener, and weighted average of leaf area. In the light grazing site of Chashtkhoran rangelands in the Cheshmeh-Kileh basin, the indices, including Simpson (P-value = 0.000), Shannon-Wiener (P-value = 0.000), functional richness (P-value = 0.001), and functional divergence (P-value = 0.08), were more than the heavy grazing site in the Mianband rangeland of the Zaremrood basin. Moreover, the weighted average of the leaf area (P-value = 0.001) was greater in the Chashtkhoran area under light grazing than in the Mianband rangeland. It was higher in the heavy grazing of the Mianband than in the Chashtkhoran Rangeland, but the weighted average of the dry matter content (P-value = 0.001) was vice versa. According to the PCA results, the first component belonged to Simpson, Shannon-Wiener, functional richness, and functional divergence, and the second component is related to evenness, functional evenness, the weighted average of leaf area, the weighted average of dry matter content, and height mean. Due to their high impact, therefore, these factors were identified as the most effective factors in separating areas under light and heavy grazing. The first and second components explain 36.3% and 19.8% of the changes, respectively.
Conclusion: The significant interaction between climate and grazing shows that the difference between the light and heavy grazing areas of the two climate zones is characterized by two variables, viz. the weighted averages of leaf area and dry matter content. The leaf area showed higher values for heavy grazing plots in the dry region, and this factor was greater in the light grazing of the humid region. This study highlights the importance of grazing control as an effective management tool for vegetation conservation. It seems that the plant composition in the mountainous rangelands of Iran is more influenced by grazing intensity than climate differences.
Background: Decreasing or increasing diversity affects a community’s sustainability because biodiversity in any living community determines its specific function, and on the other hand, sustainability is considered the ability of an ecosystem to preserve and maintain its function. At the same time as the global threats of climate change and the increase in harvesting intensity in the last few decades, ecosystem functions have been the focus of many researchers. Due to the impact of biodiversity on the protection of different ecosystem functions, many studies have investigated biodiversity indicators and ecosystem functions in different environmental conditions. In the present study, species diversity (richness, Shannon-Wiener, Simpson, and evenness) and functional (functional richness, functional evenness, functional divergence, and CWM indices) indices were used to investigate their relationships with different grazing managements (light and heavy) and two different climates in the basins of Mazandaran province. This research aims to determine the role of variables influencing plant diversity and the pasture ecosystem functioning to help better manage summer pastures that play a protective role for downstream areas in watersheds.
Methods: The effects of livestock grazing were investigated on the diversity of two selected watersheds, Zaremrood and Cheshmehkileh, in the east and west of Mazandaran province. After determining plant types in each of the areas, light and heavy grazing sites were determined based on the accessibility and distance to sources, such as livestock husbandry, watering places, and roads. For sampling in the sites, the northern slopes with the same slope (0-20%) were selected to ensure homogeneity. Sampling was done using five main plots (10 × 10 m) so that three plots (1 × 1 m2) were within each plot. Thus, a total of 15 plots were used in each grazing site (light and heavy), and a total of 30 plots were used in the random-systematic design. To measure functional diversity indicators, the easily measurable functional characteristics of plants related to the level of ecosystem functioning were selected and measured in addition to species abundance data. Based on experts, opinions and a review of available sources, five traits (leaf area, leaf dry matter content, leaf specific area index, plant height, and leaf dry weight) were used to determine functional diversity. Species diversity indices were calculated in PAST software by calculating three indices of species diversity, including species richness, Shannon-Wiener diversity, and Simpson diversity. Data were statistically compared using the analysis of variance (ANOVA) in the form of the general linear model (GLM) and principal component analysis (PCA) to separate the grazing regions that can be separated using functional diversity indices.
Results: The dependent variables (weighted average of leaf area and dry matter content) were significantly different in various climates and different livestock grazing patterns. Similarly, the independent variables (area and livestock grazing) were significantly different from the variables of species richness, Shannon-Wiener, and weighted average of leaf area. In the light grazing site of Chashtkhoran rangelands in the Cheshmeh-Kileh basin, the indices, including Simpson (P-value = 0.000), Shannon-Wiener (P-value = 0.000), functional richness (P-value = 0.001), and functional divergence (P-value = 0.08), were more than the heavy grazing site in the Mianband rangeland of the Zaremrood basin. Moreover, the weighted average of the leaf area (P-value = 0.001) was greater in the Chashtkhoran area under light grazing than in the Mianband rangeland. It was higher in the heavy grazing of the Mianband than in the Chashtkhoran Rangeland, but the
Conclusion: The significant interaction between climate and grazing shows that the difference between the light and heavy grazing areas of the two climate zones is characterized by two variables, viz. the weighted averages of leaf area and dry matter content. The leaf area showed higher values for heavy grazing plots in the dry region, and this factor was greater in the light grazing of the humid region. This study highlights the importance of grazing control as an effective management tool for vegetation conservation. It seems that the plant composition in the mountainous rangelands of Iran is more influenced by grazing intensity than climate differences.
Keywords: Cheshmehkileh Basin, Community Weighted Average, Species Richness, Summer Rangelands, Zaremrood Basin.
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