Effect of environmental gradients on diversity and plant community distribution in remnant dry Afromontane forest of Mount Duro, Nagelle Arsi, Ethiopia

Abstract For forest ecosystem management to be effective, explicit understanding of the species diversity-environmental relationship along elevation gradient is crucial. This study aimed at identifying and describing plant communities and also documenting their species diversity. Evaluation of relationships between selected environmental variables and species diversity was another objective of this study. Systematic sampling techniques were used to collect vegetation data in a total of forty two sample plots (size=20×20 m). Within main plots, four sub-plots of 5×5 m were established at four corners and – one sub-plot of the same size in the center. These plots were used for shrub and herb diversity assessment. Within each sample plot, all plant species were documented and their scientific names were identified. Environmental variables, such as: elevation, aspect and slope, were also recorded for each main plot. Species diversity was determined using Shannon-Wiener diversity index and evenness in R statistical software. Agglomerative hierarchical clustering method was used for plant community classification. The total of 44 plant species belonging to 30 families was documented. Four plant community types were identified with different diversity, evenness and species richness. These plant communities were: Afrocurpus falcatus-Ficus sur, Maesa lanceolata-Bersama abyssinica, Vernonia myriantha-Urera hypselodendron and Croton machrostachus-Tecleanobilis occurring at average elevation of 2521, 2429, 2329, and 2364 m asl, respectively. Maesa lanceolata-Bersama abyssinica community type exhibited the highest species diversity and evenness followed by Croton machrostachus-Teclea nobilis community type showing the fact that median elevation ranges were rich in species. Elevation and slope gradient explained significant variation in species richness in the studied forest. For effective conservation of biodiversity and sustainable management of the forest ecosystem, further research on the impacts of anthropogenic disturbances and soil properties is recommended as a result of this study.

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Plant community diversity and composition provide little resistance to Juniperus encroachment

Botany ◽

10.1139/b08-110 ◽

2008 ◽

Vol 86 (12) ◽

pp. 1416-1426 ◽

Cited By ~ 12

Author(s):

Amy C. Ganguli ◽

David M. Engle ◽

Paul M. Mayer ◽

Eric C. Hellgren

Keyword(s):

Species Richness ◽

Species Diversity ◽

Species Composition ◽

Plant Species ◽

Plant Community ◽

Tallgrass Prairie ◽

Abiotic Factors ◽

Community Diversity ◽

Oak Forest ◽

Old Field

Widespread encroachment of the fire-intolerant species Juniperus virginiana L. into North American grasslands and savannahs where fire has largely been removed has prompted the need to identify mechanisms driving J. virginiana encroachment. We tested whether encroachment success of J. virginiana is related to plant species diversity and composition across three plant communities. We predicted J. virginiana encroachment success would (i) decrease with increasing diversity, and (ii) J. virginiana encroachment success would be unrelated to species composition. We simulated encroachment by planting J. virginiana seedlings in tallgrass prairie, old-field grassland, and upland oak forest. We used J. virginiana survival and growth as an index of encroachment success and evaluated success as a function of plant community traits (i.e., species richness, species diversity, and species composition). Our results indicated that J. virginiana encroachment success increased with increasing plant richness and diversity. Moreover, growth and survival of J. virginiana seedlings was associated with plant species composition only in the old-field grassland and upland oak forest. These results suggest that greater plant species richness and diversity provide little resistance to J. virginiana encroachment, and the results suggest resource availability and other biotic or abiotic factors are determinants of J. virginiana encroachment success.

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Plant Community Analysis along Environmental Gradients in Moist Afromontane Forest of Gerba Dima, South-western Ethiopia

10.21203/rs.3.rs-19997/v1 ◽

2020 ◽

Author(s):

Abyot Dibaba Hundie ◽

Teshome Soromessa Urgessa ◽

Bikila Warkineh Dullo

Keyword(s):

Cluster Analysis ◽

Species Diversity ◽

Plant Species ◽

Plant Community ◽

Plant Communities ◽

Environmental Gradients ◽

Floristic Composition ◽

Regional Government ◽

Community Types ◽

Western Ethiopia

Abstract Background This study was carried out in Gerba Dima Forest, South-Western Ethiopia, to determine the floristic composition, species diversity and community types along environmental gradients. Ninety sample plots having a size of 25 × 25 m (625 m2) were laid by employing stratified random sampling. Nested plots were used to sample plants of different sizes and different environmental variables. All woody plant species with Diameter at breast height (DBH) ≥ 2.5 cm and height ≥ 1.5 m were recorded in 25 m X 25 m plots. Within the major plots, five 3 m x 3 m subplots (9 m2) was used to collect shrubs with dbh < 2.5 cm and > 1.5 m height. Within each 9 m2subplots, two 1 m2 subplots were used to collect data on the species and abundance of herbaceous plants. Hierarchical (agglomerative) cluster analysis was performed using the free statistical software R version 3.6.1 using package cluster to classify the vegetation into plant community types. Redundancy Analysis (RDA) ordination was used in describing the pattern of plant communities along an environmental gradient. Result One hundred and eighty plant species belonging to 145 genera, 69 families and comprising of 15 endemic species were recorded. Cluster analysis resulted in five different plant communities and this result was supported by the ordination result. RDA result showed altitude was the main environmental variable in determining the plant communities. The ANOVA test indicated that the five community types differ significantly from each other with regard to EC and K. Conclusions The studied forest can play a significant role in biodiversity conservation since it harbours high species diversity and richness. Thus, all Stakeholders including Oromia Forest and wildlife enterprise (OFWE) and the regional government should work to designate the forest as a biosphere reserve and being registered under UNESCO.

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The invasive herb Lupinus polyphyllus can reduce plant species richness independently of local invasion age

Biological Invasions ◽

10.1007/s10530-021-02652-y ◽

2021 ◽

Author(s):

Marju Prass ◽

Satu Ramula ◽

Miia Jauni ◽

Heikki Setälä ◽

D. Johan Kotze

Keyword(s):

Species Richness ◽

Plant Species ◽

Plant Community ◽

Plant Communities ◽

Vascular Plant ◽

Plant Species Richness ◽

Ecological Impacts ◽

Plant Community Composition ◽

Lupinus Polyphyllus ◽

Local Invasion

AbstractThe ecological impacts of invasive species may change or accumulate with time since local invasion, potentially inducing further changes in communities and the abiotic environment. Yet, time since invasion is rarely considered when investigating the ecological impacts of invasive non-native species. To examine the effect of time since invasion on the ecological impacts of Lupinus polyphyllus, a perennial nitrogen-fixing herb, we surveyed vascular plant communities in the presence and absence of L. polyphyllus in young, intermediate, and old semi-natural grassland sites (ca. 5, 10, 15 years representing both time since lupine invasion and plant community age). We analyzed vascular plant community composition, vascular plant species richness, and the cover of various ecological plant groups and L. polyphyllus. In contrast to our hypotheses, we found no change in the mean cover of L. polyphyllus (about 35%) with time since local invasion, and an ordination did not suggest marked changes in plant community composition. L. polyphyllus was associated with lower species richness in invaded plant communities but this effect did not change with time since invasion. Invaded plant communities were also associated with lower occurrence of generalist, oligotrophic (low-nutrient-adapted) and copiotrophic (nutrient-demanding) species but no temporal dynamics were detected. We conclude that even the intermediate cover of L. polyphyllus can reduce plant species richness, but the ecological impact caused by this invader might not dramatically change or accumulate with time since invasion.

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Eucalyptus plantations in temperate grasslands: responses of taxonomic and functional diversity of plant communities to environmental changes

10.1101/2020.10.12.334011 ◽

2020 ◽

Author(s):

Pamela E. Pairo ◽

Estela E. Rodriguez ◽

M. Isabel Bellocq ◽

Pablo G. Aceñolaza

Keyword(s):

Species Richness ◽

Leaf Litter ◽

Plant Species ◽

Functional Diversity ◽

Plant Communities ◽

Environmental Variables ◽

Canopy Cover ◽

Land Uses ◽

Eucalypt Plantations ◽

Plantation Age

ABSTRACTUnderstanding how human land-uses impact on local communities is required to implement management and conservational policies and practices. Tree plantations have become one of the fastest-growing land uses in recent decades and their impact on biodiversity was evaluated mainly at the taxonomic level. Our aim was to analyze the effects of changes in environmental drivers along the 12 years eucalypt plantations chronosequence on alfa, beta, taxonomic and functional diversity of understory plant communities. We selected nine plantation ages with three replicates per age and three protected grasslands as reference habitat. At each replicate, we established three plots to measure plant species cover and environmental variables, which are expected to change with plantation age. Results showed that species richness and all diversity indices significantly declined with increasing plantation age. Canopy cover, soil pH, and leaf litter were the most important drivers that explained the decline in taxonomic and functional diversity of plants through the forest plantation. Based on the Path analyses results, canopy cover had an indirect relationship with plant functional diversity mediated by leaf litter, soil pH and plant species richness. The results of the association between functional traits and environmental variables have revealed that high dispersal potential, annual, barochorous, and zoochorous plant species were the functional traits more affected by the eucalypt plantations. Given that leaf litter was negatively associated with all diversity facets, we recommend reducing their accumulation within eucalypt plantation to enhance biodiversity conservation and the provision of pampean grassland ecosystem functions.

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Pattern of Plant Community Distribution along the Elevational Gradient and Anthropogenic Disturbance in Gole Forest, Ethiopia

International Journal of Ecology ◽

10.1155/2020/6536374 ◽

2020 ◽

Vol 2020 ◽

pp. 1-9

Author(s):

Mesfin Belete Hailemariam ◽

Tamru Demsis Temam

Keyword(s):

Species Composition ◽

Plant Species ◽

Plant Community ◽

Plant Communities ◽

Environmental Variables ◽

Similarity Index ◽

Hierarchical Cluster ◽

Elevational Gradient ◽

Agglomerative Hierarchical Cluster Analysis ◽

The Difference

Vegetation-environment relationships are usually studied along elevational gradient. The patterns of plant community distribution in Gole forest, Ethiopia, were studied along elevational gradient and disturbances. Disturbances were recorded following the elevational gradient. For vegetation data collection, 62 sample plots of size 20 × 20 m were established along an elevational gradient (2728–3480 m.a.s.l). Data on species composition and environmental variables were measured and recorded in each plot. The elevation of each sample plot was measured using Garmin GPS. Anthropogenic disturbances in each plot were estimated using the following scales: 0 = no disturbance, 1 = slightly disturbed, 2 = moderately disturbed, and 3 = highly disturbed. R statistical package was used for cluster and ordination analysis. Boxplots and analysis of variance were used to assess the relationships between plant communities and environmental variables. Sorensen’s similarity coefficient was used to detect similarities and dissimilarities among communities. A total of 114 plant species belonging to 57 families and 94 genera were identified. Five plant community types were identified using agglomerative hierarchical cluster analysis. Every plant community had differences in composition and environmental variables. The variation in plant community distributions was significantly related to elevation and disturbance. Plant community distribution was negatively correlated with elevation ( P < 0.05 ) and also with disturbance ( P < 0.05 ). Sorensen’s similarity index showed that there was a difference in the distribution of plant species composition among the communities. The difference in plant community distribution of Gole forest was significantly related to elevation. Disturbances also have a considerable influence on the plant communities and mitigation of disturbance should be the main measure that needs to be taken into account in conservation planning in the study area.

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Plant community associations with environmental variables in a semi-deciduous tropical forest of the Dominican Republic

10.1101/2020.08.04.235390 ◽

2020 ◽

Author(s):

José Ramón Martínez Batlle ◽

Yntze van der Hoek

Keyword(s):

Dominican Republic ◽

Plant Species ◽

Plant Community ◽

Plant Communities ◽

Environmental Variables ◽

Deciduous Forest ◽

Forest Loss ◽

Habitat Types ◽

Site Specific ◽

The Caribbean

AbstractDespite being increasingly threatened by human-induced disturbances, dry forests remain the least studied and protected forest types in the Caribbean region. In contrast to many other forest systems in the world, we have little knowledge of the site-specific variation in vegetation communities within these forests, nor understand how plant species distribution is determined by environmental variables, including among them geological attributes. Here, we assessed the associations between plant communities and habitat types in a semi-deciduous forest of the Dominican Republic. We collected vegetation data from 23 sites within the Ocoa river basin, which we classified into six groups with a Random Forest algorithm, lithology, geomorphology, topography, and last decade history of forest loss as predictor variables. We established three main clusters: one group which encompassed sites with forest over a limestone substrate, four groups of sites with forests over a marlstone substrate with varied degrees of steepness and forest loss history, and one group that gathered all sites with forest over an alluvial substrate. In order to measure the associations of plant communities with groups of sites, we used the indicator value index (IndVal), which indicates whether a plant species is found in one or multiple habitat types, and the phi coefficient of association, which measures species preferences for habitats. We found that 16 species of woody plants are significantly associated with groups of sites by means of their indices. Our findings suggest that the detection of plant species associations with our selection of environmental variables is possible using a combination of indices. We show that there is considerable variation in plant community composition within the semi-deciduous forest studied, and suggest that conservation planning should focus on protection of this variation, while considering the significance and variability of geodiversity as well. In addition, we propose that our indicator groups facilitate vegetation mapping in nearby dry forests, where it is difficult to conduct thorough vegetation or environmental surveys. In short, our analyses hold potential for the development of site-specific management and protection measures for threatened semi-deciduous forests in the Caribbean.

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Plant Community Analysis along Environmental Gradients in Moist Afromontane Forest of Gerba Dima, South-western Ethiopia

10.21203/rs.3.rs-19997/v3 ◽

2021 ◽

Author(s):

Abyot Dibaba Hundie ◽

Teshome Soromessa Urgessa ◽

Bikila Warkineh Dullo

Keyword(s):

Cluster Analysis ◽

Species Diversity ◽

Plant Species ◽

Plant Community ◽

Plant Communities ◽

Environmental Gradients ◽

Floristic Composition ◽

Endemic Plant ◽

Community Types ◽

Western Ethiopia

Abstract Background: This study was carried out in Gerba Dima Forest, South-Western Ethiopia, to determine the floristic composition, species diversity and community types along environmental gradients. Ninety sample plots having a size of 25 X 25m (625m2) were laid by employing stratified random sampling. Nested plots were used to sample plants of different sizes and different environmental variables. All woody plant species with Diameter at breast height (DBH) ≥ 2.5 cm and height ≥ 1.5m were recorded in 25 m X 25 m plots. Hierarchical (agglomerative) cluster analysis was performed using the free statistical software R version 3.6.1 using package cluster to classify the vegetation into plant community types. Redundancy Analysis (RDA) ordination was used in describing the pattern of plant communities along an environmental gradient. Result: One hundred and eighty plant species belonging to 145 genera, 69 families and comprising of 15 endemic species were recorded. Of these, 52 species (28.9%) were trees, 6 species (3.33%) were Trees/shrubs, 31 species (17.22%) were shrubs, 76 species (42.22%) were herbs, and 15 species (8.33%) were Lianas. Rubiaceae, Acanthaceae and Asteraceae were the richest family each represented by 11 genera and 11 species (6.11%), 9 genera and 11 species (6.11%), 6 genera and 11 species (6.11%), respectively of total floristic composition. Cluster analysis resulted in five different plant communities and this result was supported by the ordination result. RDA result showed altitude was the main environmental variable in determining the plant communities. The ANOVA test indicated that the five community types differ significantly from each other with regard to Electrical Conductivity and Potassium. Conclusions: Description of floristic diversity of species in Gerba Dima forest revealed the presence of high species diversity and richness. The presence of endemic plant species in the study forest shows the potential of the area for biodiversity conservation.

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Plant Community Analysis along Environmental Gradients in Moist Afromontane Forest of Gerba Dima, South-western Ethiopia

10.21203/rs.3.rs-19997/v2 ◽

2020 ◽

Author(s):

Abyot Dibaba Hundie ◽

Teshome Soromessa Urgessa ◽

Bikila Warkineh Dullo

Keyword(s):

Cluster Analysis ◽

Species Diversity ◽

Plant Species ◽

Plant Community ◽

Plant Communities ◽

Environmental Gradients ◽

Regional Government ◽

Afromontane Forest ◽

Community Types ◽

Western Ethiopia

Abstract Background: This study was carried out in Gerba Dima Forest, South-Western Ethiopia, to determine the floristic composition, species diversity and community types along environmental gradients. Ninety sample plots having a size of 25 X 25m (625m 2 ) were laid by employing stratified random sampling. Nested plots were used to sample plants of different sizes and different environmental variables. All woody plant species with Diameter at breast height (DBH) ≥ 2.5 cm and height ≥ 1.5m were recorded in 25 m X 25 m plots. Within the major plots, five 3m x 3m subplots (9m 2 ) was used to collect shrubs with dbh < 2.5 cm and > 1.5m height. Within each 9m 2 subplots, two 1m 2 subplots were used to collect data on the species and abundance of herbaceous plants. Hierarchical (agglomerative) cluster analysis was performed using the free statistical software R version 3.6.1 using package cluster to classify the vegetation into plant community types. Redundancy Analysis (RDA) ordination was used in describing the pattern of plant communities along an environmental gradient. Result: One hundred and eighty plant species belonging to 145 genera, 69 families and comprising of 15 endemic species were recorded. Cluster analysis resulted in five different plant communities and this result was supported by the ordination result. RDA result showed altitude was the main environmental variable in determining the plant communities. The ANOVA test indicated that the five community types differ significantly from each other with regard to EC and K. Conclusions: The studied forest can play a significant role in biodiversity conservation since it harbours high species diversity and richness. Thus, all Stakeholders including Oromia Forest and wildlife enterprise (OFWE) and the regional government should work to designate the forest as a biosphere reserve and being registered under UNESCO. Keyword s: Gerba Dima; Indicator species; Moist Afromontane Forest; Species diversity

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Ecological and floristic study of Hirmi woodland vegetation in Tigray Region, Northern Ethiopia

Ecological Processes ◽

10.1186/s13717-020-00257-2 ◽

2020 ◽

Vol 9 (1) ◽

Author(s):

Mehari Girmay ◽

Tamrat Bekele ◽

Sebsebe Demissew ◽

Ermias Lulekal

Keyword(s):

Species Diversity ◽

Plant Species ◽

Plant Community ◽

Plant Communities ◽

Vegetation Structure ◽

Floristic Composition ◽

Individual Species ◽

Shannon Diversity ◽

Regeneration Status ◽

Community Types

Abstract The dryland area in Ethiopia covers a substantial region endowed with diverse plant resources. However, the landmass has received less attention even if it has high ecological, environmental, and economic uses. The present study was conducted in Hirmi woodland vegetation, which is one of the dryland areas in Ethiopia, with the objective of investigating the floristic composition, plant community types, vegetation structure, community-environment relations and its regeneration status. Vegetation and environmental data were collected from 80 sampling plots with a size of 25 m × 25 m designated as the main plots. Diameter at breast height (DBH), height, basal area, density, vertical structure, importance value index (IVI), and frequency were computed. Species diversity and evenness were analyzed using Shannon diversity and evenness indices. The plant community types and vegetation-environment relationships were analyzed using classification and ordination tools, respectively. A total of 171 vascular plant species belonging to 135 genera and 56 families were recorded. About 5.3% of the species were endemic and near-endemic to Ethiopia. The highest number of species was recorded in families Fabaceae (16.4%) and Poaceae (11.7%) followed by Asteraceae (7.0%), Combretaceae, Lamiaceae, and Moraceae (3.5% each). Five plant communities were identified. According to the results from ordination analysis, the floristic composition of these plant communities was significantly affected by altitude, slope, sand, silt, soil organic matter, total nitrogen, and disturbance. The vegetation structure reveals that a large number of individual species was categorized in the lower DBH, frequency, and height classes. The highest Shannon diversity index and evenness values of the study area were 4.21 and 0.95, respectively. Anogeissus leiocarpa, Combretum hartmannianum, Ziziphus mucronata, Terminalia macroptera, and Acacia polyacantha were the species with high IVI. Some endemic plants were in the IUCN red list categories of Ethiopia and Eritrea. The overall regeneration status of the study area was poor because of anthropogenic disturbances and grazing pressures. Although the study area is endowed with high plant species diversity including endemism, it is under poor regeneration status due to various disturbances. To overcome this challenge, integrated management measures including monitoring and application of restoration techniques by taking into consideration the significant environmental factors associated with species diversity as well as observed regeneration status and IUCN threat level of the species are highly recommended.

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