Native Plant Diversity Research Articles

Which factor contributes most to the invasion resistance of native plant communities under the co-invasion of two invasive plant species?

Two invasive plant species (IPS) can co-invade the same plant community. As the number of IPS increases under the co-invasion of two IPS, plant taxonomic and functional diversity, community invasibility, community stability, invasion resistance, and invasion intensity and invasiveness of IPS and their interrelationships may be altered. This study aimed to quantify the contribution of plant taxonomic and functional diversity, community invasibility, community stability, and invasion intensity and invasiveness of IPS to the invasion resistance of native plant communities under the co-invasion of the two IPS Erigeron annuus (L.) Pers. and Solidago canadensis L. in eastern China. This study also defined a method to quantify the invasion resistance of native plant communities designated the invasion resistance index. The community-weighted mean trait values of native plants and plant diversity are the factors that are the most critical to determine the invasion resistance of native plant communities. Thus, the invasion resistance of native plant communities primarily depends on the three following factors: the relative abundance of natives, the growth performance of natives, and the diversity of natives. All levels of invasion significantly decrease the invasion resistance of native plant communities. The two IPS antagonistically affect the invasion resistance of native plant communities less under co-invasion compared with their independent invasion.

Effect of road corridors on plant diversity in the Qionglai mountain range, China

We analyzed the impact of mountain roads on patterns of species richness and community dissimilarity along elevation gradients with linear mixed-effects models, assessed how non-native/annual species modified these patterns of diversity, and explored changes in the effects of road on plant diversity along topographic gradients through the generalized additive model (GAM). Data analysis showed that (i) species richness for all, native and perennial species was unimodal relative to elevation and peaked at middle elevations; these patterns were modified by colonization of non-native and annual species favored by roads; (ii) mountain roads homogenized community compositions by selective extinction of native perennial species and to a lesser extent by colonization of annuals, rather than by colonization of non-native species; roads did not affect beta diversity response to elevation gradient; and (iii) mountain roads only contributed 8.98 % plant diversity at the landscape level; species richness was affected more by roads than by beta diversity. Montane ecosystems showed strong resilience to the influence of road the at landscape level. We suggest that new roads be planned and constructed on northeast-facing slopes and at lower elevations in order to minimize negative impacts on native plant diversity.

Managing an Invasive Species While Simultaneously Conserving Native Plant Diversity

Management for invasive species is usually done with the intent of maintaining or enhancing one or several ecosystem services. On rangeland landscapes, management is often focused on provisioning services (e.g., livestock) but can also include maintaining biodiversity. Rangeland landscapes are often large and complex, suggesting understanding the invasion and management efforts is best done at multiple scales. The objective of this study was to assess the effectiveness of sericea lespedeza (Lespedeza cuneata [Dum.-Cours] G. Don) management practices on two study areas that were focused on managing livestock and promoting biodiversity simultaneously. At one study area, an experiment containing 134 different prescribed fires was evaluated for 19 yrs comparing pyric herbivory with traditional rangeland management with fire and grazing on sericea lespedeza invasion. The second area had a 21-yr observational study across 16 000 ha with 541 different prescribed burns and on the effects of pyric herbivory and herbicide applications on sericea lespedeza. We found support that pyric herbivory with cattle (Bos spp.) or bison (Bos bison) contributed to long-term invasion mitigation for sericea lespedeza, whereas we found no support that other management practices added to the mitigation provided by pyric herbivory. We found no support for a season of fire effect and/or herbicide control. These practices only provided short-term sericea management (1 yr). Pyric herbivory remains the only viable management action that can reduce the rate of invasion and use this invasive forage legume for livestock production at actual management scales. This study demonstrates the importance of developing large-scale studies of realistic treatments that integrate practices such as fire, grazing, and herbicides to understand the effects of invasion and control efforts on rangelands with multiple objectives.

Quantifying latitudinal variation in land surface phenology of Spartina alterniflora saltmarshes across coastal wetlands in China by Landsat 7/8 and Sentinel-2 images

Spartina alterniflora is an aggressive invasive plant spreading along the coastal China, spanning a latitudinal range of 20°N - 39°N, and its invasion resulted in dramatic decline in both native plant diversity and ecosystem functioning. Phenology of S. alterniflora saltmarshes is a critical feature to elucidate the invasion dynamics over geographical regions but has not been well understood yet. In this study, we examined the variation of S. alterniflora saltmarsh phenology across coastal China during 2018–2020 by using time series Landsat 7/8 and Sentinel-2 images. Combined Landsat 7/8 and Sentinel-2 images provided more good-quality observations in a year, which could facilitate phenological retrieval. We applied and assessed three widely used phenology retrieval methods (i.e., NDVI-based pixel-specific statistical threshold, NDVI-based double logistic mathematical equation, and LSWI-based biological threshold) for retrieving the start and end of season (SOS and EOS) as well as the length of season (LOS) of S. alterniflora saltmarshes. The SOS and EOS dates derived from three phenology retrieval methods showed similar patterns in latitudinal phenology variation: SOS became later and LOS became shorter as latitude increased, and the latitudinal trend of EOS was not as large as that of SOS. This study shows the potential of Landsat 7/8 and Sentinel-2 to quantify land surface phenology of S. alterniflora saltmarshes, which not only enhances our understanding of the spatial-temporal dynamics of coastal saltmarshes in China but also improves the management of this plant invader that threatens native saltmarshes in the world.

Functional diversity and habitat preferences of native grassland plants and ground-dwelling invertebrates in private gardens along an urbanization gradient.

Urbanization is occurring around the globe, changing environmental conditions and influencing biodiversity and ecosystem functions. Urban domestic gardens represent a small‐grained mosaic of diverse habitats for numerous species. The challenging conditions in urban gardens support species possessing certain traits, and exclude other species. Functional diversity is therefore often altered in urban gardens. By using a multi‐taxa approach focused on native grassland plants and ground‐dwelling invertebrates with overall low mobility (snails, slugs, spiders, millipedes, woodlice, ants, rove beetles), we examined the effects of urbanization (distance to city center, percentage of sealed area) and garden characteristics on functional dispersion, functional evenness, habitat preferences and body size. We conducted a field survey in 35 domestic gardens along a rural–urban gradient in Basel, Switzerland. The various groups showed different responses to urbanization. Functional dispersion of native grassland plants decreased with increasing distance to the city center, while functional dispersion of ants decreased with increasing percentage of sealed area. Functional evenness of ants increased with increasing distance to the city center and that of rove beetles decreased with increasing percentage of sealed area. Contrary to our expectation, in rove beetles, the proportion of generalists decreased with increasing percentage of sealed area in the surroundings, and the proportion of species preferring dry conditions increased with increasing distance to the city center. Body size of species increased with distance to city center for slugs, spiders, millipedes, ants, and rove beetles. Local garden characteristics had few effects on functional diversity and habitat preferences of the groups examined. Our study supports the importance of using multi‐taxa approaches when examining effects of environmental change on biodiversity. Considering only a single group may result in misleading findings for overall biodiversity. The ground‐dwelling invertebrates investigated may be affected in different ways from the more often‐studied flying pollinators or birds.

Species richness, phylogenetic diversity and phylogenetic structure patterns of exotic and native plants along an elevational gradient in the Himalaya

BackgroundSo far, macroecological studies in the Himalaya have mostly concentrated on spatial variation of overall species richness along the elevational gradient. Very few studies have attempted to document the difference in elevational richness patterns of native and exotic species. In this study, this knowledge gap is addressed by integrating data on phylogeny and elevational distribution of species to identify the variation in species richness, phylogenetic diversity and phylogenetic structure of exotic and native plant species along an elevational gradient in the Himalaya.ResultsSpecies distribution patterns for exotic and native species differed; exotics tended to show maximum species richness at low elevations while natives tended to predominate at mid-elevations. Native species assemblages showed higher phylogenetic diversity than the exotic species assemblages over the entire elevational gradient in the Himalaya. In terms of phylogenetic structure, exotic species assemblages showed majorly phylogenetic clustering while native species assemblages were characterized by phylogenetic overdispersion over the entire gradient.ConclusionsThe findings of this study indicate that areas with high native species richness and phylogenetic diversity are less receptive to exotic species and vice versa in the Himalaya. Species assemblages with high native phylogenetic overdispersion are less receptive to exotic species than the phylogenetically clustered assemblages. Different ecological processes (ecological filtering in case of exotics and resource and niche competition in case of natives) may govern the distribution of exotic and native species along the elevational gradient in the Himalaya.

Evolution of the ecosystem in Baiyangdian Lake

Baiyangdian Lake, which is also known as the “Kidney of North China” and “Pearl of North China,” is the largest among 143 lakes of different sizes in Haihe plain located in central Hebei province. The water quality in Baiyangdian Lake is moderately and mildly eutrophic; it reaches the surface water Class IV standard with seasonal variations. Combined with data from previous studies, ecological changes in Baiyangdian Lake over the past 70 years are elaborated herein. With the rapid development of industrial economies, the environment of Baiyangdian Lake has been damaged dramatically since the 1950s. The potential risk level of cadmium in Baiyangdian Lake sediments varies from moderate to severe. The contents and varieties of microplastics and antibiotics detected in Baiyangdian Lake have also increased. The diversity and abundance of native plants, animals, and microorganisms have been influenced by multiple environmental factors and human activities. In this paper, the distribution characteristics and sources of pollutants are summarized by discussing the diversity and abundance of plants, animals, and microorganisms in Baiyangdian Lake. This study would provide important scientific data and theoretical support for the pollution control and ecological service function improvement of Baiyangdian Lake.

Plant–soil feedback during biological invasions: effect of litter decomposition from an invasive plant (Sphagneticola trilobata) on its native congener (S. calendulacea)

AbstractPlant invasions can affect soil properties in the invaded habitat by altering the biotic and abiotic nature of soils through positive or negative plant–soil feedback. Litter decomposition from many invasive species enhanced soil nutrients, thereby decreasing native plant diversity and leading to further plant invasions. Here, we examined the impact of litter decomposition from an invasive plant (Sphagneticola trilobata) in a range of soils at varying depths on growth and physiology of its native congener (Sphagneticola calendulacea). We added litter from S. trilobata to each soil type at different depths (0, 2, 4 and 6 cm). Plants of S. calendulacea were grown in each treatment, and morphological and physiological parameters were measured at the end of the growing period. All soils treated with litter displayed increases in soil nutrients at depths of 2 and 4 cm; while most growth traits, leaf chlorophyll and leaf nitrogen of S. calendulacea decreased at the same soil depths. Therefore, litter decomposition from invasive S. trilobata resulted in a positive plant–soil feedback for soil nutrients, and a negative plant–soil feedback for growth in native S. calendulacea. Our findings also suggest that the effects of litter decomposition from an invasive plant on soils and native species can vary significantly depending on the soil depth at which the litter is deposited. Future studies should focus on plant–soil feedback for more native and invasive species in invaded habitats, and the effects of invasive litter in more soil types and at greater soil depths.

Short‐term nutrient reduction reduces cover of an invasive winter annual grass without negatively impacting the soil microbial community

Invasive winter annual grasses have degraded ecosystems around the world, forming large monocultures. However, common management methods, such as tillage, herbicide, and prescribed burning, also reduce native plant diversity and harm the soil microbial community. Early‐season, short‐term nutrient reduction applied to intact vegetation to manage invasive winter annual grasses could potentially decrease their abundance, while not impacting later season species. Low rates of sucrose, a labile carbon, were applied in a Pacific Northwest semiarid grassland in early spring to stimulate microbial growth and reduce nutrient availability to the invasive grass Ventenata dubia. Inorganic nitrogen was tracked throughout the experiment and plant and soil microbial community changes were determined at the end of the growing season. Sucrose application reduced nitrogen at the beginning of the season, but effects did not persist to mid‐May when most plants were still active and soil moisture was not limiting. Treatments reduced V. dubia cover, per area seed production, and seed mass with no corresponding impact on perennial or other annual plants, except at the highest application rate when annual cover was reduced by 2%. The soil microbial community, determined via phospholipid fatty acid and neutral lipid fatty acid analysis, and the soil nematode community were largely unchanged at the end of the growing season with no reduction in the abundance of arbuscular mycorrhizal fungi. This short‐term nutrient reduction method has the potential to not only target invasive winter annual grasses, but any plants that are active earlier or later than the rest of the community.

Native plant establishment on a custom modular living wall system in a humid subtropical climate

The aim of this study was to determine if local or regional native plants might be suitable for use on a custom living wall system (LWS) located in a humid subtropical climate. Nineteen taxa of plants native to the ecoregion or adjacent ecoregions were installed into 297 custom-designed modules fabricated from galvanized sheet metal by-products. This study reports plant survival and health ratings of 75 plants installed in May 2018 and 240 in May 2019. Evaluations taken in September and December of 2019 report that mean health ratings of all plants ranged from 1 to 5 with mean values of 3.6 to 3.68. Survivability rates ranged from 79 % to 100 % for 7 species of succulents, 53 %–186 % for the 11 species of herbaceous perennials, and 100 % for the one species of grass. Planting by location of the upper wall or lower had some, but minimal effect on plant survival. Through this study, we observed that plant selection should correspond with LWS goals regarding maintenance requirements, wall appearance, and the watering needs of plants. This study reports baseline data for the establishment of native plant taxa and plant diversity on a living wall system in a humid subtropical climate.

A Floral Checklist for Wheaton Regional Park, Montgomery County, Maryland

Wheaton Regional Park is a suburban 500-acre park in Montgomery County, Maryland, on the northern edge of the Washington, D.C., metropolitan area. Early floristic surveys of the park, conducted between 1961–1964 when the park was founded, showed the park to be diverse, with 443 taxa of vascular plants. Our research team conducted a second round of floristic surveys between 2014–2019 to update the checklist of plants in the park. Here, we present a comprehensive checklist of all species collected in the park over the past 50 years, discuss recent plant introductions, and share a platform for a digital flora of the park through the Mid-Atlantic Megalopolis online portal. We documented 393 vascular plant species from the 1960s, as part of a comprehensive review of those collections. The 2010s collections recorded 293 vascular plant species, and an additional 16 species of bryophytes. In total, 554 species of plants (vascular and non-vascular) in 326 genera and 118 families have been recorded in Wheaton Regional Park over the past 50 years. We found that the surveys in the 2010s identified a substantial number of vascular plant species that were not recorded in the 1960s surveys. Additionally, we were able to recover less than half of the vascular plants recorded in the 1960s. The proportion of non-native vascular plant species increased from 22.1% in the 1960s to 34.5% in the 2010s. We offer recommendations for preserving the extant diversity of native plants in the park.

Plants critical for Hawaiian land snail conservation: arboreal snail plant preferences in Puʻu Kukui Watershed, Maui

AbstractThe Hawaiian archipelago was formerly home to one of the most species-rich land snail faunas (> 752 species), with levels of endemism > 99%. Many native Hawaiian land snail species are now extinct, and the remaining fauna is vulnerable. Unfortunately, lack of information on critical habitat requirements for Hawaiian land snails limits the development of effective conservation strategies. The purpose of this study was to examine the plant host preferences of native arboreal land snails in Puʻu Kukui Watershed, West Maui, Hawaiʻi, and compare these patterns to those from similar studies on the islands of Oʻahu and Hawaiʻi. Concordant with studies on other islands, we found that four species from three diverse families of snails in Puʻu Kukui Watershed had preferences for a few species of understorey plants. These were not the most abundant canopy or mid canopy species, indicating that forests without key understorey plants may not support the few remaining lineages of native snails. Preference for Broussaisia arguta among various island endemic snails across all studies indicates that this species is important for restoration to improve snail habitat. As studies examining host plant preferences are often incongruent with studies examining snail feeding, we suggest that we are in the infancy of defining what constitutes critical habitat for most Hawaiian arboreal snails. However, our results indicate that preserving diverse native plant assemblages, particularly understorey plant species, which facilitate key interactions, is critical to the goal of conserving the remaining threatened snail fauna.

Initial conditions influence effects of prescribed burns and deer exclosure fences on tree regeneration and understory diversity in Appalachian oak-dominated forests

Sustaining oak-dominated forests that support regionally important biodiversity in the Appalachian Mountains is a substantial challenge for land managers due to mesophication – a region-wide phenomenon in which forest composition shifts from oaks to shade tolerant, mesic species such as maples. To inform oak forest management that includes biodiversity preservation as a management objective, we established a two treatment factorial design experiment at two sites to determine the effects of prescribed fire and deer herbivory on tree regeneration and understory plant diversity in dry oak-dominated forests. Data were collected before and after treatments were applied. Prescribed burns altered species composition to favor fire-adapted species and deer exclosure fences protected woody and herbaceous species sensitive to deer browse at both sites, however the initial conditions in the forests profoundly influenced the effects of these treatments. Prescribed fires promoted oak seedlings over maple seedling where oak seedlings were well stocked. Conversely, burning favored maple seedlings to the detriment of oak seedlings in areas where chronic over-browsing resulted in a depauperate understory. Although fire reduced understory plant cover at both sites, overall understory species richness was not affected by burning. This suggests that prescribed fire did not have detrimental effects on forest understory diversity, although herbaceous species diversity was significantly reduced by burning the site with an initially depauperate understory. Fencing resulted in large increases in species richness and cover of understory plants, including more than doubling the cover of tree seedlings and the abundance of tall seedlings in fenced plots, as well as shifts in understory composition towards species sensitive to deer browse. The herbaceous layer in this study contained nearly 6 species for every one species found in the tree canopy, reaffirming the importance of the herbaceous layer in the biodiversity of Appalachian oak-dominated forests. These results provide guidance to managers of protected areas seeking to enhance oak regeneration while maintaining or promoting native plant diversity in the forest understory.

Owners’ Perceptions Do Not Match Actual Ground-Dwelling Invertebrate Diversity in Their Gardens

Urban gardens are important for human well-being, biodiversity and other ecosystem functions. Biodiversity-promoting initiatives would benefit from their owners being aware of the state of biodiversity in their gardens. We examined whether garden owners’ perceptions match actual biodiversity in their gardens and whether perceptions are influenced by the owners’ ecological knowledge. We used a structured interview to assess the motivations and biodiversity knowledge of owners of 33 domestic gardens in the city of Basel (Switzerland) and related them to a survey of native plants and several groups of ground-dwelling invertebrates in their gardens. Owners showed different priorities, with promotion of habitat for biodiversity, receiving, on average, higher scores than cultivation, recreation and garden designing. Owners prioritizing biodiversity promotion had gardens with high habitat richness. The garden owners’ perceptions of both native plant and overall invertebrate diversity were not correlated with actual diversity data for native plants and ground-dwelling invertebrates. The perceptions of the abundance of invertebrate groups by garden owners with good biodiversity knowledge were not more accurate than those from owners with less knowledge. Despite their willingness, many owners do not know all the opportunities to promote biodiversity. Initiatives to further biodiversity-friendly gardening should thus transfer knowledge.

Agricultural land use curbs exotic invasion but sustains native plant diversity at intermediate levels

Unveiling the processes driving exotic plant invasion represent a central issue in taking decisions aimed at constraining the loss of biodiversity and related ecosystem services. The invasion success is often linked to anthropogenic land uses and warming due to climate change. We studied the responses of native versus casual and naturalised exotic species richness to land uses and climate at the landscape level, relying on a large floristic survey undertaken in North - Eastern Italy. Both climate and land use drove exotic species richness. Our results suggest that the success of plant invasion at this scale is mainly due to warm climatic conditions and the extent of urban and agricultural land, but with different effects on casual and naturalized exotic species. The occurrence of non-linear trends showed that a small percentage of extensive agricultural land in the landscape may concurrently reduce the number of exotic plant while sustaining native plant diversity. Plant invasion could be potentially limited by land management, mainly focusing on areas with extensive agricultural land use. A more conscientious land management is more and more commonly required by local administrations. According to our results, a shift of intensive to extensive agricultural land, by implementing green infrastructures, seems to be a win–win solution favouring native species while controlling the oversimplification of the flora due to plant invasion.

Regeneration of Riparian and Maritime Pine Forests after a Large Wildfire on the Largest Public Forest of Portugal

Eighty-six percent of the largest Portuguese public forest, Leiria National Forest (Mata Nacional de Leiria—MNL), central west, was burned in a wildfire in October 2017. Most of the area was covered by maritime pine stands (Pinus pinaster Aiton) crossed by riparian forests along small-sized streams. This work aims to characterize the post-fire vegetation and evaluate its natural regeneration. Sampling was carried out c. 6 months after the fire in 28 plots distributed at pine stands (3.5 × 3.5 m2) and in 24 plots (5 × 20 m2) at stream channels and riverbanks. These latter surveys were repeated in 2019. Data include the floristic composition and cover data of pine stands and streams, and the number of pine seedlings. Six months after the fire, 60% and 93% of the pre-fire species were observed at streams and pine stands, respectively. Fire severity was not related to differences in flora composition, nor with species richness. Pine seedlings were significantly more abundant in pine stands >60 years old compared to younger (<25 y) stands, but no significant differences were observed in the regeneration of understory. On riparian landscapes, the germination and resprouting of invasive exotic species, such as Acacia sp., created dense vegetation formations with decreased native plant diversity and altered the ecosystem structure. Following large wildfires, such as the one in MNL, managers should prioritize preserving the natural regeneration potential in the soil and aerial seed banks.

Environmental DNA sampling provides new management strategies for vernal pool branchiopods in California.

California’s vernal pools are declining ecosystems that support valuable native plant and animal diversity. Vernal pool branchiopods are particularly at risk from vernal pool habitat loss and conservation efforts have targeted their long-term protection through the establishment of preserves and conservation banks. These conservation strategies require repeated, perpetual monitoring of preserved habitat, which is currently carried out through dip-net surveys and visual identification of specimens. Dip-netting may be destructive and frequently requires some sacrifice of protected species. Environmental DNA offers a new, modern method to monitor many protected freshwater organisms. We designed qPCR-based species-specific assays for four of California’s vernal pool branchiopods: The Vernal Pool Fairy Shrimp Branchinecta lynchi (BRLY), the Midvalley Fairy Shrimp Branchinecta mesovallensis (BRME), and the Conservancy Fairy Shrimp Branchinecta conservatio (BRCO), and the Vernal Pool Tadpole Shrimp Lepidurus packardi (LEPA). We tested these assays using eDNA sampling protocols alongside traditional dip-net surveys to assess their viability as an alternative method to monitor vernal pool branchiopods. Based on occupancy modeling, each of our assays achieved a 95% or higher detection rate when using optimized sampling protocols.

Studies of urban flora in Russia: current state and prospects

An overview of Russian literature sources of urban flora studies. The authors analyze the history of urban floral research in Russia and provide definitions of terms – urban flora, native, indigenous, apophytic, alien, synanthropic species. The overview provides a description of methods and approaches used in different studies of urban flora. Special attention is paid to the analysis of the biological diversity of native and alien plants and the features of their spatial distribution in urban habitats. The authors raise problems of protection of biodiversity in cities and show the role of urban protected natural areas. The conclusion of the work outlines the prospects for further study of urban flora. The authors highlight an importance and necessity of creation of a unified database of vascular plants in the urbanized territories of Russia. Further usage of the database will allow to conduct a comparative analysis of the species composition of urban flora and to identify the degree of their homogenization and originality.

Drastic loss of insects (Lepidoptera: Geometridae) in urban landscapes in a tropical biodiversity hotspot

Accelerating urbanization of natural areasis a particularly important threat to biodiversity in tropical countries. Understanding how this phenomenon affects different groups of the fauna is essential to develop conservation actions We evaluate the effects of urbanization on species diversity and composition of geometrid moths in a tropical biodiversity hotspot in southern Ecuador. Moths were collected at different land-use types: forest, forest-pasture, pasture, and urban. We collected a total of 3064 moths representing 299 morphospecies. Species richness of geometrid moths decreased drastically in the more urbanized areas and moth communities differed strongly in composition between the investigated habitats. Community composition was mainly affected by floristic composition and degree of urbanization. Beta diversity components between land-use types depend on the degree of disturbance, with turnover among communities dominant in initial transitions and nestedness prevailing at later stages of transitions. In summary, moth assemblages in this tropical biodiversity hotspot are not only severely impoverished due to urbanization, but the remaining assemblages are strongly different from those found in natural ecosystems. Implications for insect conservation. To mitigate negative effects we recommend a more cautious development of urbanized areas in the region through the creation of more green space within the city, mainly with high diversity of native plants which can serve as potential hosts for caterpillars of moths and multiple other insects.

Non-Native Eragrostis curvula Impacts Diversity of Pastures in South-Eastern Australia Even When Native Themeda triandra Remains Co-Dominant.

Lowland grassy woodlands in Australia’s south-east face reductions in native plant diversity because of invasion by non-native plants. We compared the relative abundance and diversity of plant species among sites dominated by the native Kangaroo grass (KG) Themeda triandra with sites co-dominated by the non-native African lovegrass (ALG) Eragrostis curvula and KG. We found significant differences in plant species composition depending on the dominant species. Furthermore, our results revealed differences in several diversity parameters such as a lower species richness and forb diversity on sites co-dominated by ALG and KG. This was the case despite the functional similarity of both ALG and KG—both C4 perennial tussock grasses of a similar height. Therefore, our results highlight the critical function of the native KG in maintaining and enhancing the target plant species composition and diversity within these grassy woodlands. Herbivore grazing potentially impacts on the abundance of the dominant grass and forb species in various ways, but its impact likely differs depending on their evolutionary origin. Therefore, disentangling the role of individual herbivore groups (native-, non-native mammals, and invertebrates) on the plant community composition of the lowland grassy woodlands is essential to find appropriate grazing regimes for ALG management in these ecosystems.