Herbaceous Plant Communities Research Articles

The interacting influences of competition, composition and diversity determine successional community change

Abstract Community change is one of the few constants in nature, and the balance of mechanisms influencing this change is central for understanding the structure and functioning of communities and ecosystems. Newly established communities undergo succession and can change in diversity and composition as local environmental change, interspecific interactions and immigration play out over time. Understanding the influence of initial conditions and priority effects (long‐term consequences of the initial community composition and species identity) on community change is critically important for both evaluating ecological theory and predicting restoration outcomes. Here I evaluate how initial experimental conditions in 2012, like initial sown species richness, phylogenetic diversity and early biomass production, along with priority effects caused by the identity of sown species, influence subsequent herbaceous plant community composition and the number of colonizing species after 9 years of uninterrupted natural colonization. I found that sown phylogenetic diversity (measured as mean pairwise distance) indirectly affected the number of colonizing species by increasing biomass production early on and plots with more biomass in 2012 were colonized by fewer species. Individual species influenced the number of colonizing species with taller species reducing the number of colonists and some shorter species subject to a greater number of colonists. Synthesis. Taken together, these results indicate that initial composition influences the number of colonizing species via community‐wide competition. These findings suggest that restoration outcomes can be greatly influenced by decisions about sown species composition and early management practices.

Drought release and post-drought changes in herbaceous composition and diversity in two land uses subjected to selective bush control in a semi-arid Kalahari savanna

Land degradation due to bush encroachment and drought threatens the well-being of land users and forage production in the semi-arid savannas of southern Africa. This study aimed to analyse how herbaceous vegetation in the Kalahari savanna can recover from drought, and how this is affected by previously implemented bush control measures. We compared plant species composition and diversity of the herbaceous layer across a drought-release (2021) and post-drought (2022) year within two land use types (game and livestock) in bush-encroached and controlled areas, respectively. Diversity decreased significantly during the post-drought year. Annual species dominated in the drought-release year, which were replaced by perennial forbs and dwarf shrubs in the post-drought year. Selective bush control enhanced herbaceous species abundance and richness due to decreased competition. The species richness was higher in the game ranch compared to the cattle farm during the drought-release year. Herbaceous abundance, however, increased on the cattle farm. The management strategies, feeding behaviour and animal movement may have contributed to these differences in these two contrasting land use types. This study showed that herbaceous plant communities can recover rapidly after a drought period and in areas where bush control was applied.

Fine‐scale variation in soil and topography influences herbaceous vegetation and the distribution of large mammalian herbivores

AbstractCurrent understanding of the distribution of vegetation and large mammalian herbivores (LMH) is based on a combination of biogeographic studies and highly controlled field experiments, but a more complete understanding of these patterns requires study of their natural co‐occurrence patterns at intermediate spatial scales. The study was conducted in the 120‐ha Mpala Forest Global Earth Observatory (ForestGEO) plot, Kenya. We examined differences in herbaceous plant communities and habitat use by LMH among three topographic habitats with distinct soil types, namely steep slopes, valley and plateau. Each pair of habitats differed in plant and animal composition. The steep slopes and plateau respectively had ≥1‐fold higher percentage herbaceous cover than the valley, whereas the steep slopes and valley had >1.5‐fold greater grass species richness and diversity than the plateau. The activity of LMH was ≥1.7‐fold higher in the valley than the steep slopes and plateau, reflecting a positive relationship between LMH activity index and richness and diversity of grass species. Results indicate that fine‐scale variation in topography and soil are associated with both the distribution of herbaceous vegetation and LMH, suggesting a need to account for local habitat characteristics when examining the distributions of plants, animals, and plant‐herbivore interactions in natural systems.

Contrasting effects of species richness on soil pollutant removal in herbaceous plant communities: the importance of individual species

Many studies have shown that increasing species diversity generally increases ecosystem functioning, but few have evaluated the role of species diversity in soil pollutant removal, especially for organic pollutants. We test the hypothesis that increasing plant diversity can enhance soil pollutant removal. To test the hypothesis, we conducted two experiments: one for removal of cadmium and the other for removal of cypermethrin from the soil. In both experiments, plants were grown in monocultures, four‐ and eight‐species mixtures in soils contaminated with the pollutants. Contaminated soils without plants were also included as controls. Our results showed that the efficiency of cadmium removal from the soil decreased with increasing plant species richness. The negative effect of diversity on cadmium removal was largely attributed to species underyielding in plant mixtures. In contrast, the efficiency of cypermethrin removal from soils increased with increasing plant species richness. The positive effect of diversity on cypermethrin removal was likely due to the presence of Taraxacum mongolicum which had the lowest biomass but the highest removal efficiency. Our results suggest that species diversity may regulate pollutant remediation, and this is pollutant‐dependent. Moreover, the performance of individual species can strongly influence the direction and magnitude of the diversity effect on soil pollutant removal. These species should be treated with cautious in the remediation of contaminated soils.

Dispersal and persistence traits inform long-term herbaceous plant community change in encroached savannas

Dispersal and persistence traits inform long-term herbaceous plant community change in encroached savannas

Discrepancies between the drivers of alpha and beta plant diversity in arable field margins.

Field margins are major habitats for biodiversity conservation and ecosystem functioning in agricultural landscapes, but biotic homogenization of plant communities threatens their ecological and agronomic functions. Our objective is to determine the drivers of plant diversity in field margins for conservation and restoration purposes. To do so, we assessed the effects of field margin structure and long-term management over 20 years (1995-2015) on the taxonomic and functional α- and β-diversity, and the functional composition of herbaceous plant communities. In 2015, we surveyed 302 field margins in bocage landscapes of Brittany, northwestern France. Results were very similar between taxonomic and functional diversity but revealed important discrepancies between the drivers of α- and β-diversity. Deep ditches, mowing and grazing increased α-diversity but did not affect β-diversity. Denser hedgerows had lower α-diversity than other field margins but strongly contributed to β-diversity by harbouring more unique sets of species or life strategies. Long-term herbicide spraying in field margins and cropping intensity in adjacent habitats did not affect α-diversity, but had more complex effects on β-diversity and selected for common weeds. All in all, preservation of dense hedgerows, abandonment of herbicide spraying, and protection against agrochemical drifts are key measures to prevent the establishment of common weeds and biotic homogenization of herbaceous plant communities in field margins. Above all, our study shows how important it is to go beyond α-diversity to make robust conservation and restoration decisions.

Twenty Years of Urban Reforestation: Overstory Development Structures Understory Plant Communities in Lexington, KY, USA

Urban forests provide critical ecosystem services in an increasingly urbanized global landscape. The reforestation of undeveloped parcels and serially mowed grasslands can increase urban forest cover, but plant community development in planted urban forests is poorly understood. We conducted a study to elucidate the roles of time since tree planting, invasive species abundance, and other abiotic and biotic site-level factors in structuring understory plant communities within a 20-year chronosequence of planted urban forests in Lexington, KY, USA. We assessed the percent of groundcover of all understory species in fixed-radius plots on the site. Understory herbaceous plant communities demonstrated shifts from graminoid dominance to forb dominance over time, and plant communities in successively younger sites were increasingly dissimilar from that of the 20-year-old site. Invasive plant species were abundant, representing 21% of total groundcover across all surveyed plots, and became increasingly prevalent over time. Understory plant diversity was negatively associated with invasive species abundance. Overall, site factors, including time since planting, forest canopy closure, density of tree and shrub reproduction, and soil pH, accounted for much of the variability among understory communities. Understory plant communities across the chronosequence of planted sites demonstrated apparent structural shifts with overstory canopy development, but the increasing prevalence of invasive species and their negative impacts to plant diversity warrant future management to ensure the continuation of the desired successional trajectories.

Soil seed banks along a woody plant removal gradient in a semi-arid savanna of South Africa: Implications for restoration

Woody plant encroachment threatens ecosystem services and functions, thereby reducing herbaceous plant population persistence and community stability. Consequently, woody plant control projects are implemented in South Africa to restore herbaceous vegetation. Because persistent seeds drive passive restoration and vegetation trajectories, management following woody plant control entails examining soil seed bank (SSB) size and composition. However, a knowledge gap exists regarding how SSB characteristics respond along a woody plant removal gradient. This study was conducted at Roodeplaat in Gauteng Province of South Africa to assess the impact of woody density reduction [hereafter woody plant removal intensity (WPRI)] on SSB density, composition, diversity and richness. Woody plant vegetation composed of a mixture of species, mainly Vachellia robusta, Ziziphus mucronata, Euclea species and Pappea capensis. Selective tree removal was applied to downscale woody density (4065 ± 109 plants ha−1) of the control (0% WPRI) to 10, 20, 50, 75 and 100% WPRIs in four blocks, resulting in four replicates per WPRI. A total of 120 soil samples (n = 20 per WPRI) were collected at 5 cm depth after 3 years of tree removal. Germination method was used to assess the SSB. Fifty-one species, mainly forbs (n = 26) and grasses (n = 16) were recorded from 32 237 seeds. The SSB densities of grasses increased from 649 to 6000 seeds m−2 from 0 to 100% WPRI whilst sedges and forbs exhibited differential declining trends along WPRI gradient. Cyperus rotundus accounted for more than one-third of the SSB densities at 0 and 10% WPRIs, whereas Panicum maximum contributed nearly half (46%) to the SSB density at 100% WPRI. Woody plant removal increased SSB diversity (H′) and richness, but diversity peaked at 20% WPRI (H' = 1.78); thereafter it declined. Overall, our results signified that complete woody plant clearing has a potential for restoration of woody-encroached rangelands through increasing SSB size and species richness.

Species diversity and productivity of pasture ecosystems of the Ilovlinsky sand massif

The aim of the research was to establish the productivity of pasture ecosystems on the sandy lands of the Don basin. The objects of research are herbaceous plant communities on the sands of the Ilovlinsky massif of the Volgograd region. The analysis of the species diversity of the vegetation cover, its variability in space was carried out by an inventory of 5 test plots measuring 10 x 10 m. Generally accepted methods of statistical analysis, graphical interpretation and scientific generalization were used to process, analyze and present the results. In all the surveyed sites, there is a low proportion of Fabaceae family species (0-8 %), a large proportion of the mixed grass group (58-75 %) and the weed species of plants (26-50 %) species. The feed mass consumed on average in the plots is 11-45 g / m2. A direct relationship was revealed between the influence of the percentage of Poaceae and Cyperaceae (Carex) species in the phytocenosis on medium-grown sands on the increase in the yield of sandy pastures (g / m2) in the late autumn period (r = 0.99). The condition of the soil and vegetation cover on forage lands is a consequence of overgrazing.

Classification scheme for mapping wetland herbaceous plant communities using time series Sentinel-1 and Sentinel-2 data

Classification scheme for mapping wetland herbaceous plant communities using time series Sentinel-1 and Sentinel-2 data

Relationships between denitrification rates and functional gene abundance in a wetland: The roles of single- and multiple-species plant communities

Wetland soil denitrification removes excess inorganic nitrogen (N) and prevents eutrophication in aquatic ecosystems. Wetland plants have been considered the key factors determining the capacity of wetland soil denitrification to remove N pollutants in aquatic ecosystems. However, the influences of various plant communities on wetland soil denitrification remain unknown. In the present study, we measured variations in soil denitrification under different herbaceous plant communities including single Phragmites karka (PK), single Paspalum thunbergia (PT), single Zizania latifolia (ZL), a mixture of Paspalum thunbergia plus Phragmites karka (PTPK), a mixture of Paspalum thunbergia plus Zizania latifolia (PTZL), and bare soil (CK) in the Estuary of Nantiaoxi River, the largest tributary of Qingshan Lake in Hangzhou, China. The soil denitrification rate was significantly higher in the surface (0–10 cm) than the subsurface (10–20 cm) layer. Wetland plant growth increased the soil denitrification rate by significantly increasing the soil water content, nitrate concentration, and ln(nirS) + ln(nirK). A structural equation model (SEM) showed that wetland plants indirectly regulated soil denitrification by altering the aboveground and belowground plant biomass, nitrate concentration, abundances of denitrifying functional genes, and denitrification potential. There was no significant difference in soil denitrification rates among PT, PK and ZL. The soil denitrification rate was significantly lower in PTZL than PTPK. Two-plant communities did not necessarily enhance the denitrification rate compared to single planting, the former had a greater competitiveness on N uptake and consequently reduced the amount of nitrate available for denitrification. As PTPK had the highest denitrification rate, co-planting P. thunbergia and P. karka could effectively improve N removal efficiency and help mitigate eutrophication in adjacent aquatic ecosystems. The results of this investigation provide useful information guiding the selection of appropriate wetland herbaceous plant species for wetland construction and the removal of N pollutants in aquatic ecosystems.

Comparative impacts of dam water level regimes on herbaceous plant growth strategies in cascade reservoirs and downstream reaches of a major river

Abstract Flow regulation is a prolific and growing influence on rivers world‐wide. Nine cascade hydropower dams were constructed along the 1,150‐km Wujiang River in China over the past 30 years, disrupting longitudinal continuity. Water level fluctuations in the associated reservoirs range between daily, weekly, seasonal, and annual, depending on the type of regulation, but the comparative impacts of these regimes on plant growth strategies, or the extent of their downstream influence, is unknown. Competitor, stress‐tolerator, and ruderal (CSR) plant strategies were used to assess the impact of reservoir regulation type on the riparian herbaceous plant community based on sampling the inundation zone of nine reservoirs and their downstream river reaches during 2017 and 2018. Our results revealed profound differences in CSR plant strategies of the dominant vegetation with respect to water level regime. While ruderal plants dominated (45%–60% of species), irrespective of regulation type, vegetation in reservoirs exhibited a strong shift from stress‐tolerators (e.g., Cynodon dactylon, C‐11.9:S‐41.5:R‐46.5%) to competitors (e.g., Reynoutria japonica, C‐77.9:S‐0:R‐22.0%) with increasing intensity of water level fluctuation, reflecting the shift from annual to daily regulation. The width of the inundation zone was the best overall variable in explaining the CSR strategies of riparian vegetation, both in the reservoir inundation zone (r2‐adj = 15.4%) and the downstream river (r2‐adj = 7.3%). Retention time significantly explained variation in CSR plant strategies in the reservoir inundation zone (r2‐adj = 3.7%, p = 0.002) but not downstream (p > 0.01). There was also a clear scale dependency of CSR plant strategies, with an increase in stress tolerators (average slope = 0.7%/km) and decline of competitor (average slope = −0.3%/km) and ruderal plants (average slope = −0.9%/km) with increasing distance downstream from dams. The growth strategies of the dominant riparian vegetation changed with the magnitude and frequency of water level fluctuations caused by differences in regulation type, and local environmental conditions. Clear scale dependency in the CSR plant strategies was observed with distance from the dam, with ruderals dominating closest to the reservoirs and declining gradually downstream as stress tolerators increased. Our study helps to evaluate the impact of river damming on the functional traits of riparian vegetation and to predict the resilience and restoration potential of riparian vegetation under different forms of human disturbance.

Effects of Invasive Plant Diversity on Soil Microbial Communities

Native plant communities can be invaded by different numbers of alien plant species or by the same number of alien plant species with different levels of evenness. However, little is known about how alien invasive plant species richness and evenness affect soil microbial communities. We constructed native herbaceous plant communities invaded by exotic plants with different richness (1, 2, 4 and 8 species) and evenness (high and low) and analyzed soil physico-chemical properties and the diversity and composition of soil fungal and bacterial communities by high-throughput Illumina sequencing. Overall, the species richness and evenness of invasive plants had no significant effect on bacterial and fungal alpha diversity (OTUs, Shannon, Simpson, Chao1 and ACE) or the soil physico-chemical properties. However, invasive species richness had a significant impact on the relative abundance of the most dominant fungi, Ascomycota and Bipolaris, and the dominant bacteria, Actinobacteriota, which increased with increasing invasive species richness. The relative abundance of the dominant microbial groups was significantly correlated with the relative abundance of some specific invasive plants in the community. This study sheds new light on the effects of plant co-invasion on soil microbial communities, which may help us understand the underlying mechanisms of multiple alien plant invasion processes from the perspective of soil microorganisms.

Vulnerability Segmentation in Ferns and Its Implication on Their Survival During Drought

Climate change is expected to increase temperature and temporal precipitation variability leading to higher evapotranspiration and more frequent and severe droughts. While advancements are being made in our understanding of how plants will respond to these changes, gaps remain in our knowledge of species-specific drought response. This is especially true among herbaceous plant communities, including ferns and other seed-free vascular plants. Previous hydraulic work on ferns has almost exclusively concentrated on the leaves, with very little information on the rhizome, which is surprising given that the rhizome is the long-lived perennial organ (making it more costly and important in species survival). Only recently have rhizome hydraulics been explored in the context of drought stress. Similar to observations in many woody trees, fern leaves tend to desiccate and hydraulically disconnect before the perennial stem experiences significant levels of drought-induced embolism, suggesting strong vulnerability segmentation. These findings have significant implications for fern survival during drought. In this review we expand on these observations, integrating information from previous work on plant hydraulics and ecophysiology, to understand the implications of vulnerability segmentation on the response of ferns to future climate change.

The Coupling Relationship between Herb Communities and Soil in a Coal Mine Reclamation Area after Different Years of Restoration

In a complete organic ecosystem restoration in mining areas, soil and vegetation complement and influence each other. It is of great significance to evaluate the ecological restoration effect on and ecosystem stability of the mining area, with the coupling and coordinating relationship between herb community and soil physicochemical properties after land reclamation. Therefore, this study takes Juxinlong Coal Mine in Dongsheng District of Ordos City, Inner Mongolia Autonomous Region as the study area. The understory herbaceous plant community and soil factors with restoration time of 3 to 7 years were selected as the research objects. In addition, artificial grassland and natural restoration grassland were used as controls to investigate the species composition of herbaceous communities and soil physicochemical properties in different sites. The grey relational coupling model was adopted not only to study the relationship between herb community and soil factors but also to explore the coupling mechanism between herb community and soils’ physicochemical properties. The results included: (1) 51 herbaceous plants were investigated in the study area, among which Gramineae, Compositae, Leguminosae, and Chenopodiaceae were the primary ones, accounting for 70% of the total. (2) With the increase of restoration years, the diversity indices of understory herbaceous plants generally showed an increasing trend, but the diversity indices of understory herbaceous plants with different restoration years was smaller than that of artificial grassland. (3) The results of grey correlation analysis showed that the diversity of herbaceous plant community in the study area was closely related to soils’ available nitrogen and water content. (4) The degree of coupling and coordinating between the diversity of herbaceous plants and soils in the study area presented a trend of first increasing then decreasing during the accumulating restoration years. Among them, the degree of coupling between the diversity of understory herbaceous plants and soil system in the 5-year restoration’s sample plot (0.73) was found to be the highest, which was classified as medium coordination. The lowest coupling degree of herb diversity and soils was identified in the artificial grassland (0.51), which was light incoordination. Therefore, it is suggested that the control of water and nitrogen resources should be strengthened, the herbaceous vegetation should be reasonably selected, and the artificial tending should be carried out in the later stage of understory herbaceous vegetation construction in the study area to better promote the vegetation construction in the mining area.

Effects of spatial distance and woody plant cover on beta diversity point to dispersal limitation as a driver of community assembly during postfire succession in a Mediterranean shrubland.

Beta diversity, and its components of turnover and nestedness, reflects the processes governing community assembly, such as dispersal limitation or biotic interactions, but it is unclear how they operate at the local scale and how their role changes along postfire succession. Here, we analyzed the patterns of beta diversity and its components in a herbaceous plant community after fire, and in relation to dispersal ability, in Central Spain. We calculated multiple‐site beta diversity (βSOR) and its components of turnover (βSIM) and nestedness (βSNE) of all herbaceous plants, or grouped by dispersal syndrome (autochory, anemochory, and zoochory), during the first 3 years after wildfire. We evaluated the relationship between pairwise beta diversity (βsor), and its components (βsim, βsne), and spatial distance or differences in woody plant cover, a proxy of biotic interactions. We found high multiple‐site beta diversity dominated by the turnover component. Community dissimilarity increased with spatial distance, driven mostly by the turnover component. Species with less dispersal ability (i.e., autochory) showed a stronger spatial pattern of dissimilarity. Biotic interactions with woody plants contributed less to community dissimilarity, which tended to occur through the nestedness component. These results suggest that dispersal limitation prevails over biotic interactions with woody plants as a driver of local community assembly, even for species with high dispersal ability. These results contribute to our understanding of postfire community assembly and vegetation dynamics.

The number of phenology patterns, not species richness, affects the greening season length of freely assembled plant communities

AbstractQuestionsPlant greening phenology is a key response trait that drives numerous ecosystem functions such as carbon storage and flowering. Plant communities with a diversity of phenology responses could show a longer greening season due to more complete occupation of the temporal window available for growth. However, it is unclear how species composition and richness affect the phenology of local plant communities.LocationThis study was conducted in wetland landscapes of the St. Lawrence River in the province of Québec, Canada (46.07°N; 73.17°W).MethodsWe used close‐range digital imagery to monitor the greening phenology and species richness of 20 herbaceous plant communities from 2013 to 2016. We quantified the number of greening phenology patterns observed each year within each plant community using singular value decomposition of close‐range image time series.ResultsThe number of plant species within plant communities was independent of the number of phenology patterns, or the length of the greening season. However, the number of phenology patterns correlated positively to the greening season length in all four years of monitoring.ConclusionsThe relationship between the number of phenology patterns and the greening season length suggests a complementary use of the temporal window available for growth within plant communities. Species richness was a poor indicator of the diversity of phenology responses in wet meadow communities. The absence of a positive relationship between the number of plant species and the diversity of greening phenology patterns, or the length of the greening season, suggests that other descriptors of plant communities are of importance. Species richness is more often than not a weak predictor of the functioning of local plant communities in the wild.

Sweep Sampling Comparison of Terrestrial Insect Communities Associated with Herbaceous Stratum in the Riparian Zone of the Miho River, Korea.

Simple SummaryInsect pests and their natural enemies can harbor in riparian zones. To determine the impact of insect communities on agriculture and ecology, we must quantitatively assess insect populations in riparian areas. To identify the appropriate methodology for effective insect sampling in riparian areas, we assessed sweep sampling within three plant communities using different numbers of subsampling units (50 sweeps carried out twice, or 10 sweeps over 10 times) over two years. The results reveal that effective insect sampling varies between different plant communities and insect orders. The similarities between terrestrial insect communities in the same plant community were relatively high, even in different years. The optimum sampling size to obtain approximately 80% of the total species was estimated for each survey site. Our results lay the foundations for providing techniques to assess insect populations within riparian areas to predict and prevent herbivorous insect pest invasions in the future.To investigate insect and plant community relationships in riparian zones, terrestrial insect communities were compared in plant communities in the riparian zone of the Miho River, Korea. The sweep netting method was used to sample insects in 50 m transects in three herbaceous plant communities. In 2020, each plant community—Chenopodium album, Beckmannia syzigachne, and Artemisia indica—was swept 100 times (50 sweeps × 2). In 2021, two communities had an additional 100 sweeps collected using 10 subsamples of 10 sweeps (excluding C. album communities). The surveyed dominant species or subdominant species of the insect community in each site preyed on the dominant plant species at the site. The Bray–Curtis similarity was significantly higher than the Sørensen similarity when comparing datasets across different years for the same plant species community. The predicted optimum sampling size to obtain approximately 80% of the total species estimated to be at each survey site, for effective quantitative collection of terrestrial insect herbivores in each plant community, was examined. Fifty sweeps were required for the A. indica community and 100 sweeps were required for the B. syzigachne community. The results of this study provide important data for riparian biodiversity conservation and future pest monitoring.

Phenological patterns of herbaceous Mediterranean plant communities in spring: is there a difference between native and formerly-cultivated grasslands?

Background and aims – Plant phenology, defined as the timing of recurring life events like leaf flushing, flowering, or fruiting, is highly sensitive to environmental factors such as photoperiod, temperature, and moisture. Phenological synchrony between interacting species – such as plants and their pollinators – is of major importance to the structure and functioning of ecosystems. Plant phenology might also be affected by changes in edaphic conditions. However, whether former agricultural activities may shift phenological patterns of plant communities remains poorly understood. In this study, we evaluated the impact of past agricultural practices on herbaceous plant community phenology in the protected Mediterranean xeric grassland of La Crau (France). Material and methods – We compared (1) species composition, and (2) phenological patterns of annuals, perennials, Bromus rubens (annual), and Lobularia maritima (perennial), in formerly-cultivated plots – abandoned for 30 years – and intact native grassland plots (steppe), both subjected to itinerant sheep grazing. Key results and conclusion – Our results suggest that former agricultural activities can affect species composition of Mediterranean xeric grassland communities with differences visible after 30 years of abandonment, but only altered phenological patterns slightly. We suggest that climatic factors and sheep grazing acted as strong habitat filters constraining community assembly at the phenological level.

Impacts of Climatic Factors on Vegetation Species Diversity, Herbaceous Biomass in Borana, Southern Ethiopia

The study was conducted in three districts of Borana Zone, with the objective to determining the impacts of climatic factors on vegetation species diversity, herbaceous biomass yield of Borana rangelands under commonial grazing rangeland types during end of growing season. The most types rangeland of communial properties are traditional enclosure and continuous grazing rangeland from in where our different data were collected. Within both rangeland types of each districts 20 m x 20 m plots that placed at 200 m distances intervals with three replication was used to collect woody vegetation. The data of herbaceous plant community was collected from seventeen quadrants (1 m x1 m) that layout in the main plot. The collected data was analyzed by linear regression to determine the impact of climate factors. The herbaceous species richness, diversity and biomass study sites had highly significantly difference (P < 0.001) and positive linear with mean annual precipitation. There is significantly difference (P < 0.05) and negative linear in woody species richness and diversity. Both herbaceous and woody plant species richness and diversity of study areas had a negative linear with mean annual temperature. Climate factors specieally rianfall have a great impact on rangeland ecosystems of study areas. Therefore, rangeland user should be considering climatic factors to improve productivity of rangeland. Keywords: Rangeland types, Species diversity and richness, herbaceous biomass and rainfall DOI: 10.7176/JEES/12-5-01 Publication date: May 31 st 2022