Native Shrubs Research Articles

Calotropis procera (Apocynaceae) shrub intrusion on wildlife foraging rangelands in the Ruaha National Park

The relationships between the encroachment of Calotropis procera (Apocynaceae) and understorey herbaceous cover and various environmental variables of recipient grasslands were studied in the north-eastern Ruaha National Park in southern Tanzania. Three hypotheses were investigated. (1) C. procera exerts a negative influence on the cover of understorey herbaceous plants. (2) C. procera exerts a negative influence on environmental variables (humidity, light intensity, soil pH, air temperature, and soil temperature). (3) The native shrub canopy exerts a negative influence on understorey herbaceous plant cover and the environmental variables. We identified two sampling areas, one encroached by C. procera, the other with only native tree/shrub species. In each area, 21 5 m × 5 m subplots were established, and within each, two 1 m × 1 m sample plots were established, one 20 cm from the stem of a C. procera or native trees/shrub, the other at 5 m distance, and herbaceous plant cover and environmental variables were measured. Variables were measured on three occasions (December 2022, March, and July 2023) on the 42 subplots in each sampling area. Results demonstrated a negative influence of C. procera on understorey herbaceous cover, with a significantly lower percentage (16 ± 1.7) of herbaceous cover for plots at 20 cm than 5 m (72.4 ± 1.4) from C. procera stems. Moreover, soil pH was significantly lower at 20 cm than at 5 m distance from the stems in the encroached area, whereas in the non-encroached area, there was no recorded difference in the environmental variables. These results emphasised the necessity for a prompt intervention to contain the spread of C. procera in suitable grazing areas. A detailed study to find out the most practical and cost-effective control approaches appears warranted.

Host range, biology, and climate suitability of Callopistria exotica, a potential biological control agent of Old World climbing fern (Lygodium microphyllum) in the USA

Old World climbing fern, Lygodium microphyllum (Cav.) R. Br., is one of the worst environmental weeds of southern and central Florida. The weed climbs over other plants, forming thick mats that block sunlight to native shrubs and trees. In the introduced range, Old World climbing fern invades much of the southern peninsula of Florida where cost-effective, sustainable control methods are needed. A potential biological control agent, the defoliating moth Callopistria exotica Guenee, was collected in Hong Kong and examined in quarantine to determine if it was safe for release. Climate modeling analysis was also performed to predict the potential climate suitability of C. exotica in the invaded range. A series of no-choice tests was conducted on 68 plant species from 45 genera, 33 plant families, and 18 orders. The results indicated that C. exotica is highly specific to the target weed, L. microphyllum and a congener that is also an exotic invasive, L. japonicum. The results indicated that the neonates fed and matured to the adult stage on the target weed L. microphyllum (0.71 ± 0.02 proportion survived) and on another invasive fern, L. japonicum (0.84 ± 0.04 proportion survived). No C. exotica neonates survived when fed the non-target species L. oligostachyum. A low proportion survived to the adult stage when fed the non-targets L. palmatum (0.07 ± 0.03), L. venustum (0.01 ± 0.01), and L. volubile (0.07 ± 0.03). Additionally, the few larvae that survived to the adult stage when fed L. palmatum and L. volubile had longer development times (130–150 % longer) and lower pupal weights (70–90 % lower) than those fed the target weed. All neonates perished within 3 days when fed the remaining 62 species evaluated in these no-choice tests. Climate modeling indicated that the suitability of North American climates for the establishment of C. exotica are very high in south Florida but are very unsuitable north of the L. microphyllum invaded range. These results indicated that this potential biological control agent is highly specific to L. microphyllum and L. japonicum and will have no, or very low survival on other non-target species. The release of C. exotica is expected to assist in the effort to manage the invasive weed Old World climbing fern.

Size class, sex ratio, and spatial distribution of four populations of Pimelea microcephala subsp. microcephala under different long-term rainfall regimes

The separation of sexes in dioecious plants enables males and females to adopt different strategies to balance reproduction and growth, but can also lead to female susceptibility due to their high reproductive burden. Understanding if a dioecious species is susceptible or adaptable in the face of worsening abiotic conditions would be useful for revegetating habitats under climate change. Our study compared four populations of the Australian native shrub, Pimelea microcephala subsp. microcephala (n = 885) across an annual rainfall gradient of ∼250–400 mm to understand the impact of decreasing rainfall on size classes, growth metrics, sex ratio, the proportion of juveniles and spatial distributions. We found that irrespective of site rainfall, male and female plants achieved similar sizes. The populations exhibited four size classes, defined by height, diameter and sex, but not site rainfall (unpaired group method with arithmetic mean cluster analysis, p < .05). Spatially, populations reflected the clumped distribution of overlying canopy cover, and did not demonstrate niche partitioning between sexes. The lack of population variation with rainfall indicates that the species may be suitable for arid zone revegetation in arid regions with declining rainfall. Conservation management of the species should include maintaining canopy tree cover to encourage seed dispersal.

Shading and species diversity act as safety nets for seedling survival and vitality of native trees in dryland forests: Implications for restoration

Restoring degraded dryland requires a diverse mix of trees and shrubs with suitable characteristics. Unfortunately, many restoration projects have failed in tropical drylands due to monoculture plantations or a lack of understanding regarding specific species requirements like shading. Therefore, the central question is whether species diversity and shading can improve seedling survival and vitality in dryland conditions. We conducted a tree diversity experiment in northern Ethiopia as part of the International Diversity Experiment Network with Trees (IDENT). We used 17,280 seedlings from 9 native dry Afromontane tree and shrub species, distributed across 270 plots in three replication blocks. Each block contains a shading treatment (shaded versus non-shaded) with three levels of species richness: one-, two- and four-species mixtures with varying levels of functional diversity (FD) categorized as low, medium, and high. Survival and vitality data of the seedlings were analyzed using generalized linear mixed models (GLMMs) and linear mixed-effects models (LMMs). After two growing seasons, the overall seedling survival rate was 84%. We found significantly higher seedling survival, vitality, and chlorophyll content (SPAD value) in shaded conditions, irrespective of the tree diversity level. However, increasing species richness did improve seedling vitality in non-shaded conditions, but its impact diminished in shaded situations. The findings from this study suggest that careful selection of tree species, appropriate shading, and optimal levels of species diversity can greatly enhance the survival and performance of seedlings. This is particularly important for the successful restoration of dryland forests.

PSXIII-13 Effect of Supplementation of Red Osier Dogwood Extract on Feed Intake and Growth Performance of Newly Weaned Beef Calves

Abstract Red osier dogwood (ROD) is a Canadian native shrub plant that is rich in phenolic compounds with antimicrobial and antioxidant properties. The high phenolic compounds with antimicrobial and antioxidant properties would be beneficial to reduce oxidative stress, hence improve animal growth performance when animals are stressed. The objective of this study was to evaluate the effects of feeding ROD extract and the residue after extraction to newly weaned calves on feed intake and growth performance. Eighty crossbred Angus steers [initial body weight (BW), 254 ± 5.4 kg] were used and housed in individual feedlot pen. The experiment was a randomized complete block design in five treatments (16 steers/treatment). Five treatments were: 1) Control (without ROD); 2) 20 g/d ROD extract (RODLow); 3) 40 g/d ROD extract (RODHigh); 4) 100 g/d ROD residue (RODRes); and 5) 330 mg monensin/d (MON). The MON was used as positive control because it is commonly fed to feedlot cattle to improve feed efficiency and animal health. The experiment diet consisted of 60% silage and 40% concentrate (DM basis) and fed for 84 d. The DPPH free radical scavenging activity of ROD extracts and the residue after extraction were determined. The high DPPH scavenging was observed for both ROD extracts (60.6 ± 4.7%) and residue (80.6 ± 1.7%) at the concentration of 0.5 mg/mL. Dry matter (DM) intake (kg/d) overall did not differ between control (6.44) and ROD supplemented calves (average, 6.27), whereas the DM intake tended (P = 0.10) to be greater with ROD extract (4.97 kg/d) than control (4.56 kg/d) at the first 28 d. The final BW averaged daily gain and feed efficiency were not affected by increasing dose of ROD extract (0, 20, 40 g/d) or by adding 100 g/d ROD residue. The calves fed MON had reduced (P = 0.04) DM intake (5.72 vs. 6.32 kg/d) and decreased (P = 0.07) daily gain (0.81 vs. 0.94 kg/d) than other treatments. Fecal pH ranged from 6.98 to 6.17 and did not differ among treatments. These results indicate that feeding ROD extract or its residue to newly weaned calves may increase feed intake when the animals are stressed; however, its effect on growth performance and feed efficiency is not apparent under current feeding conditions.

Litter from Native Shrubs in the Senegal River Valley Induces Modifications in Nematode Communities and Enzyme Activities in Cultivated Sandy Soils

ABSTRACT To reduce plant-parasitic nematodes (PPNs), an alternative solution based on amendments from selected native shrub was used to favor mainly the increase of free-living nematodes (FLNs) that include high trophic (bacterivorous, fungivorous, omnivorous, and carnivorous) nematodes and influence soil microbial activities. The consequences of the subsequent reduce of PPNs of the soil were also determined. Experiments were performed in a shade house using six treatments consisting of shrub residues from Piliostigma reticulatum (Pil), Boscia senegalensis (Bos), and Crotalaria juncea (Cro); a Straw-based Compost (Cs); a Farmer practice (FP) using Nitrogen-Phosphorus-Potassium (NPK) fertilizer; and a control (C0, no amendments). Abundances of nematodes, trophic groups, and nematodes ecological indices were determined. Enzymatic activities (ß-glucosidase and acid phosphatase) and the fluorescein diacetate hydrolysis (FDA) were also determined. Soil amended by Bos and Cro increased the density of nematodes compared to control soil or amended with NPK fertilizer. Indices of taxonomic diversity (H') did not differ significantly between the treatments. However, soils amended with Bos and Cro had the highest enrichment index (EI), and the lowest Nematode Channel Ratio (NCR), indicating that these two shrub residues exhibited a higher food web in response to the available resources provided by the fungal decomposition pathway. Moreover, Bos favored omnivorous and increased enzymatic activities. Bos induce ‘bottom-up’ while Cro induce ‘top-down’ controls on nematode populations.

Ecovoltaics: Maintaining Native Plants and Wash Connectivity inside a Mojave Desert Solar Facility Leads to Favorable Growing Conditions

The installation of solar facilities is increasing rapidly in the Mojave Desert USA, with the largest facility in North America (3227 ha) currently being built 30 km north of Las Vegas, NV. At the state level, Nevada (USA) has developed an energy plan to diversify its energy portfolio by 2030 with green energy representing 50% of the energy produced. Although solar is considered a clean energy, it does require significant amounts of land and as such may have negative consequences at the habitat and ecosystem levels. A multi-year study was conducted to assess the impact a photovoltaic facility in the Mojave Desert had on the growth and physiological response of two native shrubs (Ambrosia dumosa and Larrea tridentata) growing inside and outside the facility. These species were selected because they were the dominant species at the site and are representative of desert scrub communities throughout the Mojave Desert. At the time of construction, native plants and washes were left intact inside the solar facility. The solar panel arrays were separated at either 8 m or 10 m. Plants were selected for monitoring on the basis of location: at the panel drip line, below the panels, or midway between panel rows. Abiotic factors, including PAR, reference evapotranspiration, precipitation, soil water in storage, and infiltration, were monitored bi-monthly. The growth and physiological status of the plants were assessed by monitoring leaf water potential, chlorophyll index, canopy temperatures, non-structural carbohydrates in the roots and stems, leaf tissue ion concentrations, stem elongation, and seed production. Plants at the bottom edges of the panels received more precipitation due to runoff from the panels, which led to increased soil moisture in the long spacing but not the short spacing. The lower soil water in storage in the short spacing was related to greater growth and higher soil water extraction. Although the area under the panels provided shade in the summer and warmer temperatures in the winter, the incoming PAR was reduced by as much as 85%, causing plants growing under the panels to be spindly with lower canopy volume (L. tridentata, p = 0.03) and seed yield (A. dumosa, p = 0.05). Ambrosia plants remained green in color year-round (not going into winter dormancy) inside the facility and had elevated levels of starch in their roots and stems compared with plants growing at the outside control sites (p &lt; 0.001). Larrea growing outside the facility had lower xylem water potentials compared with those inside the facility (p &lt; 0.001), lower chlorophyll index (p &lt; 0.001, Ambrosia as well), and lower stem elongation (p &lt; 0.001), supporting the conclusion that both Larrea and Ambrosia performed better inside the facility. Shifts in δ13 C suggested greater water-use efficiency at the locations with the least amount of soil water in storage. Our results support the installation of solar facilities that minimize the impact on native plants and wash connectivity (ecovoltaics), which should translate into a reduced negative impact at the habitat and ecosystem levels. Basedon our results, energy companies that embrace ecovoltaic systems that take an engineering and biological approach should provide acceptable environments for desert fauna. However, corridors (buffers) will need to be maintained between solar facilities, and fences will need to have openings that allow for the continuous flow of animals and resources.

Sagebrush-Associated Bunchgrasses Drive Invasion Resistance in a Greenhouse Experiment

Invasion of non-native annual grasses is a significant threat to the sustainability of sagebrush steppe ecosystems. Ecological resilience, the ability to bounce back after a disturbance, and resistance, the ability to withstand invasion, are influenced by both abiotic factors, such as soil temperature, moisture, elevation, and aspect, and biotic factors, such as plant community composition. We quantified the effects of moss biocrusts, native shrubs, and native perennial grasses on invasion resistance in a greenhouse experiment containing dominant sagebrush ecosystem plants and invasive grasses. We saw greatest suppression of invasive annual grass biomass in treatment replicates containing native bunchgrass species (P < 0.01). Final invasive grass biomass was 4.79 g on average when perennial grasses were not present and was reduced to 1.59 g with perennial grass competition (P < 0.01). Presence of shrubs and moss biocrusts did not decrease annual grass biomass (P = 0.38 and P = 0.25, respectively). We saw complex interactions between native plants grown in these ideal greenhouse conditions such that native perennial grass seedlings grown with sagebrush seedlings had a mean of 4.50 g more biomass (P < 0.001) relative to pots grown with bitterbrush or without shrubs, but shrubs were an average of 7.9 cm (P < 0.001) shorter and had biomass 4.75 g lower (P < 0.001) in pots grown with perennial grasses compared with shrubs grown without perennial grasses. Our results demonstrate that with increased treatment complexity, we see greater invasion resistance, but that nuanced relationships between plant community members should also be considered in managing and restoring these imperiled ecosystems.

Native and non‐native mulch resulted in increased soil moisture and reduced plant recruitment in container plant restoration of coastal sage scrub

One challenge of habitat restoration is establishing healthy native plants that survive, grow, and reproduce. The addition of mulch after initial planting is thought to enhance native plant establishment. In our efforts to restore degraded sites at Crystal Cove State Park in Southern California, we compared two experimental mulch treatments made from native and non‐native plant material to unmulched plots. We planted four different native shrub species: Eriogonum fasciculatum, Malosma laurina, Isocoma menziesii, and Diplacus aurantiacus, and measured plant size, soil moisture, and plant density in the first year. In the second year, the same measurements were taken for I. menziesii and D. aurantiacus, which had greater survivorship in the first year. Our results showed significant differences in plant height, length, and width among the species but not between mulch treatments. However, soil moisture significantly varied between treatments, with native mulch plots having the greatest volumetric water content. In addition, mulch treatments had a significant effect on naturally recruiting plant density, with both mulch treatments having fewer native and non‐native seedling densities compared to control plots. Regarding survivorship, significant differences between species and treatment were observed only in the first year. Our results confirmed that mulch effectively helped retain higher soil moisture. Both locally sourced native and non‐native mulch had this benefit, although native mulch resulted in greater increases in soil moisture. While mulch reduced non‐native plant establishment, it also limited native recruitment, leading us to recommend that mulch be used only during the initial establishment of container plants.

Herbaceous angiosperms, pteridophytes and shrubs cocktail for rapid ground cover for soil and water bioengineering in the Caribbean

Among the Nature-based Solutions currently spreading worldwide, soil and water bioengineering techniques, are used to stabilize hill slopes, earth embankment, and riverbanks. They consist in the use of living plants, sometimes coupled with dead materials, to control erosion and restore ecosystems.These approaches remain to be adapted to Neotropics and particularly to the Caribbean Islands biodiversity hotspot. The success of soil and water bioengineering designs depends on the selection of suitable native plant species and considering the hydrodynamic and geotechnical processes. In the Caribbean, data are available concerning woody species but are still lacking for the other constitutive components of riparian plant communities. The objective of this study was to identify the riparian forest understory species best suited for use in SWBE at their establishment phase. In a three-month ex situ experiment, we measured the survival rate, biomass production and root growth of propagules (cuttings and bulbils) of eleven native Caribbean species (5 herbs, 4 pteridophytes, 2 shrubs) occurring naturally in a variety of riparian environments. All the herb and shrub species studied displayed growth vigour adequate for a successful inclusion in soil and water bioengineering techniques. Among herbs, Commelina diffusa, Hymenachne amplexicaulis and Sphagneticola trilobata performed the best. Gynerium sagittatum and Dieffenbachia seguine, despite their slower growth and root development, remain suitable. Regarding the two shrubs, Ludwigia octovalvis gave better results than Clidemia hirta. Among the pteridophytes, Adiantum latifolium, Thelypteris reticulata and particularly Lycopodium cernuum appeared poorly suited to soil and water bioengineering. Acrostichum danaeifolium was the best-performing pteridophyte. These first experimental results focusing on the propagation and establishment of native herbs, pteridophytes and shrubs, allowed to identify a diversity of species of interest as cuttings for soil and water bioengineering and practical clues for their use in the Neotropics.

Ecosystem multifunctionality, maximum height, and biodiversity of shrub communities affected by precipitation fluctuations in Northwest China.

Dryland ecosystems face serious threats from climate change. Establishing the spatial pattern of ecosystem multifunctionality, maximum height and the correlation of biodiversity patterns with climate change is important for understanding changes in complex ecosystem processes. However, the understanding of their relationships across large spatial areas remains limited in drylands. Accordingly, this study examined the spatial patterns of ecosystem multifunctionality, maximum height and considered a set of potential environmental drivers by investigating natural shrub communities in Northwest China. We found that the ecosystem multifunctionality (EMF) and maximum height of shrub communities were both affected by longitude, which was positively correlated with the precipitation gradient. Specifically, the EMF was driven by high precipitation seasonality, and the maximum height was driven by high precipitation stability during the growing season. Among the multiple biodiversity predictors, species beta diversity (SD-beta) is the most common in determining EMF, although this relationship is weak. Unlike tree life form, we did not observe biodiversity-maximum height relationships in shrub communities. Based on these results, we suggest that more attention should be paid to the climatical fluctuations mediated biodiversity mechanisms, which are tightly correlated with ecosystem's service capacity and resistance capacity under a rapid climate change scenario in the future.

Salvia rosmarinus Spenn. (Lamiaceae) Hydroalcoholic Extract: Phytochemical Analysis, Antioxidant Activity and In Vitro Evaluation of Fatty Acid Accumulation.

Salvia rosmarinus Spenn. is a native Mediterranean shrub belonging to the Lamiaceae family and is well-known as a flavoring and spicing agent. In addition to its classical use, it has drawn attention because its biological activities, due particularly to the presence of polyphenols, including carnosic acid and rosmarinic acid, and phenolic diterpenes as carnosol. In this study, the aerial part of rosemary was extracted with a hydroalcoholic solution through maceration, followed by ultrasound sonication, to obtain a terpenoids-rich Salvia rosmarinus extract (TRSrE) and a polyphenols-rich Salvia rosmarinus extract (PRSrE). After phytochemical characterization, both extracts were investigated for their antioxidant activity through a classical assay and with electron paramagnetic resonance (EPR) for their DPPH and hydroxyl radicals scavenging. Finally, their potential beneficial effects to reduce lipid accumulation in an in vitro model of NAFLD were evaluated.

Photosynthesis and shoot allocation of amur honeysuckle and two native shrubs in deep shade

Photosynthesis and shoot allocation of amur honeysuckle and two native shrubs in deep shade

Flowering phenology and reproductive success of native shrub Berberis darwinii Hook. along different light environments

AbstractStudies evaluating flowering phenology and reproductive success are necessary when we want to direct a domestication project in a species with a potential productive value. We studied flowering phenology and reproductive success of Berberis darwinii growing under different light conditions in its native distribution area in the Andean Patagonian forests of Argentina. We test the hypothesis that plants grown under conditions of high‐light availability exhibit advanced phenology and higher reproductive success than those grown under conditions of lower light availability. Phenology and reproductive success were determined in three contrasting light conditions at two forest sites, which were, canopy, gap and forest edge. Plants did not bloom under the forest canopy. Flowering and fruiting period lengths were similar in both sites and light conditions of gap and forest edge during spring and summer. Although gap plants had more racemes per shoot, racemes of edge plants had more flowers, fruits and a higher proportion of flowers producing ripe fruit. We show that B. darwinii reproduction studied in the Andean Patagonian forests is conditioned by the canopy openness. Regarding reproductive success, edge plants invest less resources in flower production than gap plants to have similar fruit production.

Phytonutritional and Sensorial Assessment of a Novel Functional Beverage Formulated from an Underutilized Fruit of Carissa spinarum L.

Carissa spinarum L. belongs to the family Apocynaceae. It is a native shrub of Asia, locally known as Karonda or Karanda, and is an underutilized crop throughout the Asian region. The Karonda fruit is a rich source of vitamin C, minerals, phenolics, antioxidants, flavonoids, and other biofunctional compounds. The lack of awareness and knowledge among the community results in the wastage of fruits. Therefore, the present research was designed to formulate an easy-to-prepare beverage drink using C. spinarum fruit to evaluate the nutritional potential of the undervalued Karonda fruit. A beverage drink was formulated with three pulp concentrations: 20, 30, and 40%, each having 12, 14, and 16 °Brix, respectively. A total of nine treatments were prepared and stored for up to 10 weeks in refrigerated storage. The physicochemical parameters, such as pH, titratable acidity, vitamin C, total sugars, anthocyanin, total phenolics, flavonoids, and antioxidants, were measured at two-week intervals from 0 to 10 weeks. Additionally, a sensory assessment of the beverage was conducted. A decreasing trend in titratable acidity was exhibited among all the treatments (from treatment 1 to treatment 9), with the values decreasing from 0.815 to 0.556 as the fruit concentration increased. On the other hand, an increasing trend was observed for pH (from 3.04 to 3.37), vitamin C (from 22.2 to 31.48), reducing and non-reducing sugars, anthocyanin (from 31.95 to 110), total phenolics (from 19.86 to 32.16), flavonoids (from 0.64 to 0.77), and antioxidants (from 48.8 to 67.6) from treatment 1 to treatment 9, respectively. The sensory studies of the beverage formulations revealed that treatment 9, which consisted of a 40% fruit base and 16 °Brix, was the most acceptable for further development of the beverage at a commercial scale. This study represents a novel scientific contribution toward the utilization of the undervalued fruit of C. spinarum L. for the development of a beverage product. Ultimately, it has the potential to address food insecurity issues worldwide while offering its associated health benefits.

Dung beetles diversity and their role in nutrient cycling in livestock systems of the dry Chaco

Dung beetles represent one of the main animal groups involved in the cycling of cattle dung, modifying soil physicochemical properties, and reducing parasite incidence. However, their diversity and activity in cattle areas depends on conserving critical resources and conditions, including native vegetative composition, microclimatic and soil conditions. Whereas most previous studies were conducted in humid forests, our objective was to experimentally study the diversity and role of dung beetles in soil nutrient dynamics in native forests and shrub savannas with cattle ranching in the dry Chaco of Argentina. Using pitfall traps, we collected dung beetles in both habitats. In cow exclusions, we buried two plastic containers filled with soil and two kg of fresh cow dung on the surface and covered one with a mosquito net to prevent the access of dung beetles. After three months, we collected soil samples and analyzed nutrient contents and soil structure. Contrary to previous studies, the abundance and richness of dung beetles were higher in savannas than in native forests. In both habitats, the activity of dung beetles strongly increases phosphorous and potassium contents; however, consistent with the higher abundance, this effect was more marked in shrub savannas. In addition, we observed higher contents of total organic carbon, electrical conductivity, and calcium in native forests. Our results emphasize the critical role of dung beetles in maintaining soil quality in the most extended cattle management practices of the dry Chaco. Moreover, our results were opposite to previous studies conducted in humid forests, which could be associated with greater tolerance of native species to extreme microclimate conditions in the dry Chaco.

Complete Chloroplast Genomes and Phylogenetic Relationships of Bougainvillea spectabilis and Bougainvillea glabra (Nyctaginaceae).

Bougainvillea L. (Nyctaginaceae) is a South American native woody flowering shrub of high ornamental, economic, and medicinal value which is susceptible to cold damage. We sequenced the complete chloroplast (cp) genome of B. glabra and B. spectabilis, two morphologically similar Bougainvillea species differing in cold resistance. Both genomes showed a typical quadripartite structure consisting of one large single-copy region, one small single-copy region, and two inverted repeat regions. The cp genome size of B. glabra and B. spectabilis was 154,520 and 154,542 bp, respectively, with 131 genes, including 86 protein-coding, 37 transfer RNA, and 8 ribosomal RNA genes. In addition, the genomes contained 270 and 271 simple sequence repeats, respectively, with mononucleotide repeats being the most abundant. Eight highly variable sites (psbN, psbJ, rpoA, rpl22, psaI, trnG-UCC, ndhF, and ycf1) with high nucleotide diversity were identified as potential molecular markers. Phylogenetic analysis revealed a close relationship between B. glabra and B. spectabilis. These findings not only contribute to understanding the mechanism by which the cp genome responds to low-temperature stress in Bougainvillea and elucidating the evolutionary characteristics and phylogenetic relationships among Bougainvillea species, but also provide important evidence for the accurate identification and breeding of superior cold-tolerant Bougainvillea cultivars.

Patterns and consequences of invasion of tropical montane forests by Cestrum aurantiacum Lindl. in the Western Ghats

In the montane forest-grassland mosaics of the Western Ghats, land cover conversion to silviculture and agriculture over the last five decades has resulted in both loss of natural habitats and widespread invasion of remnant habitat patches. While invasion of the grassland habitats of the mosaic has been relatively well studied, there have been few attempts to understand the extent to which forest habitats (locally known as sholas) have been affected by the spread of exotic species. Here we examine the patterns and impacts of invasion of shola forest understoreys by Cestrum aurantiacum Lindl., an exotic shrub species. At the landscape scale, we demonstrate that the presence and abundance of this invasive in shola understories is negatively related to distance from tea plantations. Further, the intensity of invasion is higher in areas with greater seasonality of temperature and lower mean annual precipitation. At the patch scale, invasion is greatest at shola edges and away from stream courses. We find that C. aurantiacum abundance has negatively affected the regeneration of native shola tree species as well as the abundance of native shola understorey shrubs. Fifty three percent of invaded plots had no native shrubs present. In plots where both C. aurantiacum and native shrubs were present in large enough numbers, we found evidence of negative spatial dependence between stem locations of C. aurantiacum and native shrubs. Our findings have important implications for the management and conservation of these mosaics.

Temporal dynamics of soil nematode population in an Acacia saligna invaded Mediterranean sand dune ecosystem

Summary The invasive Australian tree, Acacia saligna, has been the subject of numerous studies investigating its ecological impact. However, the effect of its invasion on the soil free-living nematode population has yet to be researched. In this study, we examined the impact of A. saligna on the soil free-living nematode population in a coastal dune site with a Mediterranean climate during three sampling periods. Soil samples were collected from beneath the canopies of A. saligna trees, the native dominant shrub Retama raetam, and bare soil plots as a control. Our findings reveal that A. saligna increases the density of the soil free-living nematode population and changes its trophic and taxonomic composition. While the nematode diversity and functional index scores did not significantly differ between sampling locations, they did differ between the different sampling times, highlighting the seasonal dynamics of the soil nematode population in Mediterranean sand dunes.

Impacts of shelterbelt systems on pasture production and soil bacterial and fungal communities in agricultural fields

AbstractIntroductionShelterbelts, which provide protection for livestock and crops against severe weather conditions, have been recognised as important contributors to increased crop yields. Soil microorganisms play important roles in nutrient cycling, soil health and plant performance, thereby exerting significant influence on ecological services in terrestrial ecosystems. However, impacts of shelterbelts on soil microbial communities in pasture ecosystems remain poorly studied.Materials and MethodsHere, we assessed the effect of shelterbelts (composed of Eucalyptus and native shrubs) on the pasture and nutrient productivity as well as soil bacterial and fungal communities at four distances from the shelterbelts with two different heights in two fields during spring and summer by applying amplicon sequencing, physicochemical and nutritional value analyses.ResultsThe results showed that the shelterbelt height, distances from shelterbelts, seasons and their interactive effects substantially affected pasture yield, neutral detergent fibre, metabolisable energy and crude protein yields, but did not increase the pasture productivity in the rows adjacent to the shelterbelts. We also identified that the alpha diversity of bacteria and fungi did not significantly change across distances from the shelterbelts in both fields, but the community structure of soil bacteria and fungi was significantly influenced by distances from the shelterbelts. Interestingly, soil calcium (Ca) and shelterbelts were identified as top predictors of fungal community while soil pH and Ca was key drivers of bacterial community.ConclusionOur study provides novel knowledge in the impact of shelterbelts on pasture and nutritional production and soil microbial communities, which contributes to appropriate application and strategic management of the windbreak systems in agriculture production.