Plant Populations Research Articles

Rapid morphological change in UK populations of Impatiens glandulifera

The highly invasive Impatiens glandulifera (Himalayan balsam) is one of the most prolific and widespread invasive plants in the British Isles. Introduced in the early nineteenth century, it has now been reported in almost every vice county across the UK and is a fierce competitor that has adverse effects on the local community structure. Despite the negative impacts that invaders like I. glandulifera have on local communities, there have been very few studies which address the morphological changes that invasive plant populations have undergone since their initial introduction. This is the first study of its kind to investigate the morphological changes that have occurred in I. glandulifera. 315 herbarium specimens dating from 1865 to 2017 were used to measure changes in morphological traits such as leaf size, flower length and stomatal characteristics. We found that since 1865, there has been a significant reduction in overall leaf size, a significant reduction in stomatal density and a significant increase in the overall flower length. These results highlight the importance of monitoring the evolutionary change in prolific alien species over the course of their invasion, providing useful insights into changes in competitive ability which may prove useful in managing dispersal and providing options for potential management.

Impacts of assisted migration: An introduced herbivore has short‐term and long‐term effects on its native host plant population

AbstractAssisted migration consists of the introduction of a species to previously inhabited areas or to new suitable regions. Such introductions have been touted as a viable tool for conserving the earth's biodiversity. However, both the likely success of assisted migrations and the impacts on local communities are hotly debated. Empirical data on the local impacts of assisted migration are particularly lacking. We examined the short and long time‐scale effects of herbivory on Lonicera involucrata (Richards) Banks ex. Spreng (Caprifoliaceae) after an introduction of Euphydryas gillettii Barnes (Lepidoptera: Nymphalidae, Melitaeini) to Gunnison County, Colorado, USA, via an assisted migration in 1977. The plant is the primary larval host plant for the butterfly. We quantified plant seed production, plant survival, and population stage structure in two sets of observational experiments. We found that herbivory by E. gillettii increased L. involucrata reproduction on an annual time scale, independent of plant size and local microhabitat characteristics. Over the time since the butterfly's introduction, herbivory by E. gillettii resulted in a plant population structure biased toward smaller plants in the butterfly introduction and satellite sites compared with sites without the butterfly. Our results highlight the importance of studying the effects of assisted migrations on native populations at different temporal scales. As assisted migration becomes an indispensable tool for species conservation, our work adds to the understanding of the multi‐trophic impacts of assisted introductions on local populations and communities.

Invasion of Prosopis trees into arid ecosystem alters soil carbon and nitrogen processes and soil trace gases emissions

The invasion of drylands by leguminous mesquite (Prosopis spp.) is frequently associated with increases in the soil organic carbon (C) and nitrogen (N) pools. These increases stimulate soil microbial activity and accelerate soil C and N cycling. However, the impact of mesquite invasion on soil biogeochemistry, especially the emission of trace gases, in an ecosystem with an already established population of N-fixing plants is not well studied. To fill this knowledge gap, we quantified the in-situ soil trace gas emissions and the potential microbial activity in soils under invasive mesquite (Prosopis juliflora) trees (Prosopis), native acacia (Acacia tortilis) trees (Acacia), and in unvegetated soil between trees (Bare soil) on the western shore of the Dead Sea. To account for contributions of spatial and weather variabilities to the emission processes we conducted measurements across two geographic sites, 45 km apart, over two years, both under naturally dry soil conditions and after soil wetting. Before wetting, soil emissions of carbon dioxide (CO2) and nitric oxide (NOx) followed the order: Acacia > Prosopis ≥ Bare soil, while soil nitrous oxide (N2O) emissions were low and uniform across the three habitats. The soil inorganic N concentration, microbial biomass, and water-extractable organic C were significantly higher under the A. tortilis canopies compared with P. juliflora and Bare soil. After wetting, soil trace gases emissions increased up to 66, 1534, and 42 times, for CO2, N2O, and NOx, respectively, and remained higher under the native A. tortilis than under P. juliflora and Bare soil (Acacia > Prosopis > Bare soil). The potential soil microbial activity, however, was similar between the soils under the tree canopies. Our results show that the establishment of invasive leguminous trees increase soil CO2 and gaseous N emissions relative to the Bare soils, but not relative to native leguminous trees.

Different supplemental irrigation methods result in discrepant water use efficiency and yield by changing steps of water use process in dryland wheat

Supplemental irrigation (SI) at critical growth stages is a practical way to mitigate water shortage of winter wheat in dryland. However, the yield performance after SI is unstable in different precipitation years. To obtain a better understanding about the applicability of SI in dryland, the utilization efficiency of precipitation and irrigation water (IUE) was divided into 5 sequential ratios: water storage ratio, water consumption ratio, water transpired ratio, transpiration efficiency and harvest index. In this study, those ratios were investigated under four SI methods: no irrigation (W0), SI once at jointing (Wj), SI once at booting (Wb) and SI twice at jointing and booting (Wj+b) throughout four years. Our results showed that water storage ratio was increased under all SI treatments, but water transpired ratio was only significantly increased under Wj and Wj+b, due to their greater development of plant population compared to W0. Thus, wheat yield was greatly improved by 7–12 % under Wj and Wj+b than that under W0 in dry and normal years. However, IUE was significantly decreased under Wj+b. Compared with W0, Wj+b had higher evaporation during the fallow period and lower water consumption ratio. Furthermore, 100–300 cm subsoil water utilization was decreased under Wj+b from jointing to harvest time due to the low root length density (RDL) in subsoil. Under Wj, evaporation, subsoil water utilization and RDL were not negatively affected and water use efficiency was increased compared to W0. Thus, SI once at jointing stage is a more suitable practice in dryland wheat farmland when considering the dual goal of effectively using water while increasing yields under worse precipitation year.

Development of SSR Markers and Evaluation of Genetic Diversity of Endangered Plant Saussurea involucrata.

The conservation biology field underscores the importance of understanding genetic diversity and gene flow within plant populations and the factors that influence them. This study employs Simple Sequence Repeat (SSR) molecular markers to investigate the genetic diversity of the endangered plant species Saussurea involucrata, offering a theoretical foundation for its conservation efforts. Utilizing sequencing results to screen SSR loci, we designed and scrutinized 18 polymorphic microsatellite primers across 112 samples from 11 populations in the Bayinbuluke region. Our findings reveal high genetic diversity (I = 0.837, He = 0.470) and substantial gene flow (Nm = 1.390) among S. involucrata populations (China, Xinjiang), potentially attributed to efficient pollen and seed dispersal mechanisms. Principal Coordinate Analysis (PCoA) indicates a lack of distinct genetic structuring within the Bayinbuluke populations. The cluster analysis using STRUCTURE reflected the genetic structure of S. involucrata to a certain extent compared with PCoA. The results showed that all samples were divided into four groups. To safeguard this species, we advocate for the in situ conservation of all S. involucrata populations in the area. The SSR markers developed in this study provide a valuable resource for future genetic research on S. involucrata.

Hyperaccumulation of nickel but not selenium drives floral microbiome differentiation: A study with six species of Brassicaceae.

Intraspecific variation in flower microbiome composition can mediate pollination and reproduction, and so understanding the community assembly processes driving this variation is critical. Yet the relative importance of trait-based host filtering and dispersal in shaping among-species variation in floral microbiomes remains unknown. Within two clades of Brassicaceae, we compared diversity and composition of floral microbiomes in natural populations of focal nickel and selenium hyperaccumulator species and two of their non-accumulating relatives. We assessed the relative strengths of floral elemental composition, plant phylogenetic distance (host filtering), and geography (dispersal) in driving floral microbiome composition. Species in the nickel hyperaccumulator clade had strongly divergent floral microbiomes, the most of that variation driven by floral elemental composition, followed by geographic distance between plant populations and, lastly, phylogenetic distance. Conversely, within the selenium hyperaccumulator clade, floral microbiome divergence was much lower among the species and elemental composition, geography, and plant phylogeny were far weaker determinants of microbiome variation. Our results show that the strength of elemental hyperaccumulation's effect on floral microbiomes differs substantially among plant clades, possibly due to variation in elements as selective filters or in long-distance dispersal probability in different habitats.

Long-term post-release evaluation shows Hypogeococcus sp. is an effective biological control agent for queen of the night cactus in South Africa

ABSTRACT We conducted long-term monitoring of Hypogeococcus sp. (Pseudococcidae) as a biocontrol agent for queen of the night cactus (Cereus jamacaru De Candolle). The biocontrol agent was released at three sites representing the regions where the plant is problematic in South Africa, and both agent and plant populations were monitored over time. The proportion of plants producing fruits or flowers decreased by 36% each year, with all plants no longer flowering between two and seven years after release. Plant density reduced by 42% each year after release. Hypogeococcus sp. is an effective agent against C. jamacaru in South Africa.

Assessing the Early Establishment and Adaptability of Italian Ryegrass (Lolium multiflorum) in Irrigated and Rainfed Conditions of Punjab, Pakistan

In Punjab, Pakistan, more than 60% expenditure incurred on the feeding of livestock and offered low quality forage thus affecting the productivity of milk and meat. The less production of livestock oriented products often results malnutrition in the society. An effort was made to evaluate the Italian Ryegrass (Lolium multiflorum) early growth and its adaptation to rainfed and irrigated environments. The main objective of this study is to provide important new information for sustainable fodder production systems. The experiment used a Randomized Complete Block Design with seeds obtained from Korea and was carried out in the winter of 2023 in both rainfed Chakwal and irrigated Sargodha zone of Punjab. The plant's response to varying soil conditions and water availability was evaluated by measuring a range of growth parameters, such as plant height, population density, root and shoot biomass, root length, and the root-shoot ratio. The results show that there are significant differences between rainfed and irrigated locations as established by the statistical analysis. Italian Ryegrass in irrigated plots showed higher mean plant height (43.75 cm), higher plant population (317.50 plants/m²), higher shoot biomass (7.425 g/plant), greater length of roots (5.950 cm), and a lower root-shoot ratio (0.1135) than in rainfed areas. Additionally, the study provides data on soil profiles that show differences between the two locations in terms of pH, electrical conductivity, nitrogen, phosphorus, and potassium. The findings provide important information for enhancing Italian Ryegrass cultivation in Punjab's various agro-ecological zones, given the critical role fodder feed plays in supporting livestock and agriculture. The study provides the basis for well-informed farming practices by highlighting the importance of water management strategies to improve fodder production during scarcity period and, by consequently, animal nutrition in the area.

Influence of Plant Spacing and Bio-fertilizers on Yield and Yield Attributing Characters of Rain-fed Soybean at Damazin in Blue Nile State, Sudan

This study had the objective of evaluating the effect of biofertilizers on the performance of soybean plants under different planting spacing. It was conducted during the summer seasons of 2018 and 2019at one site at Demonstration Farm of Damazin Agricultural Research Station, Sudan. The different plant spacing designated as D1, D2, and D3 (5, 10, and 15 cm between plants) under three types of bio-fertilizers as Rhizobacteria (B1), Azotobacter (B2), Bacillus (B3) and control (B0). The experiment was laid out in Randomized Complete Block design (RCBD) with three replications as split-plots trail. The result revealed that the improvement due to the application of fertilizers with wider, spacing D3 stimulated plant growth and caused an increase in dry matter accumulation and high leaf area and gave the higher number of pods and seeds/pod, particularly at inoculation with B1 and B2 bacteria. While sowing seeds inoculated with B1or B2 under closer spacing resulted in higher seed yield per unit area. To achieve optimum results in soybean variety Sudan 1, the crop may be sown in plant spacing of 10cm with inoculation seeds with B1or B2 to achieve a high plant population per unit area to obtain higher seed yield.

Co-flowering richness has variable effects on pollen quantity and quality limitation in four Clarkia species.

Pollination failure occurs from insufficient pollen quantity or quality. However, the relative contributions of pollen quantity vs quality to overall pollen limitation, and how this is affected by the co-flowering context, remain unknown for most plant populations. Here, we studied patterns of pollen deposition and pollen tube formation across populations of four predominately outcrossing species in the genus Clarkia to evaluate how richness of co-flowering congeners affects the contribution of pollen quantity and quality to pollen limitation. We partition variation in pollen deposition and pollen tube production across individuals, populations and species to identify the main sources of variation in components of reproductive success. We further quantify the relative contribution of pollen quantity and quality limitation to the reproductive success of the four Clarkia species using piecewise regression analyses. Finally, we evaluate how variation in the number of co-flowering Clarkia species in the community affects the strength of pollen quality and quality limitation. Across all contexts, pollen deposition and the proportion of pollen tubes produced varied greatly among individuals, populations, and species, and these were not always correlated. For instance, C. xantiana received the smallest pollen loads yet produced the highest proportion of pollen tubes, while C. speciosa exhibited the opposite pattern. Yet, co-flowering richness had variable effects on the strength of pollen quantity and quality limitation among populations. Specifically, breakpoint values, which are an indicator of overall pollen limitation, were two times larger in the four-species community compared with one and two-species communities for two Clarkia species, suggesting that pollen limitation can increase with increasing richness of co-flowering congeners. Our results reveal a complex interplay between quantity and quality of pollen limitation and co-flowering context that may have different evolutionary outcomes across species and populations.

Synthetic Gene Drives in Plants: Development Strategies, Potential Applications, and Ethical Considerations

ABSTRACTWe are facing significant agricultural and environmental challenges, including herbicide‐resistant weeds that compromise crop yields and invasive plant species that disrupt local ecosystems. Traditional crop breeding methods are increasingly seen as ineffective in the face of these issues. One innovative approach involves the use of gene drives, a technology that enables targeted genetic modifications to transmit at a super Mendelian rate (>50%) and therefore, rapidly propagate through natural populations. In this perspective, we introduce the principles underlying our development of a plant synthetic toxin‐antidote drive, CAIN (CRISPR‐Assisted Inheritance utilising NPG1). We evaluate the potential of gene drives to alter the genetics of weed populations or suppress invasive plant populations. We explore various factors that influence the effectiveness of gene drives, including the emergence of suppressor mutations and life‐history traits such as sexual and asexual reproduction patterns, seed and pollen dispersal methods, and the variability in plant generation times. Additionally, we discuss the biosafety concerns related to gene drive experiments and field releases, strategies to counteract unwanted gene drives, and the ethical implications, particularly considering the risk of the intentional misuse of gene drive technology and the need for robust regulatory and monitoring frameworks.

Genetic diversity matters for restoration of a threatened saltmarsh plant in harsh environments

Abstract While genetic diversity is theorised to increase the restoration success of degraded plant populations, previous studies examining its impacts on restoration outcomes have yielded mixed results. We hypothesise that the importance of genetic diversity for the performance of plants targeted for restoration increases with environmental stress and varies with specific plant traits related to different plant successive life stages. To test this, we conducted a fully factorial common garden experiment, crossing salinity and genetic diversity under low‐ and high‐nitrogen conditions on the growth and reproduction of Scirpus mariqueter, a threatened endemic saltmarsh plant in the Yangtze Estuary. The impacts of genetic diversity varied across stress gradients and metrics. Under high stress (high salinity, low nutrients), greater diversity enhanced reproductive traits such as clonal growth and seed production, but not under low stress. Plant growth traits showed no diversity effects regardless of stress. Synthesis: Our results highlight the importance of considering intraspecific genetic diversity in ecological restoration and help explain the context‐dependent effects of diversity.

A pollinator crisis can decrease plant abundance despite pollinators being herbivores at the larval stage

Pollinating insects are decreasing worldwide due to various environmental stresses (so-called pollinator crisis), raising concerns that plant productivity could be undermined in natural and agricultural ecosystems. To date, however, few studies have reported a concurrent decline in both pollinators and plants, and little is known about when a “plant crisis” occurs. Here, we propose that anthropogenic environmental stresses on pollinating insects (e.g. climate change, habitat loss, and pesticide usage) can negatively affect herbivorous insects (e.g., pollinator larvae and crop pests) as well, and effects of pollinator declines may be masked by positive effects of herbivore declines. To test the idea, we theoretically investigated plant population dynamics mediated by two insect groups: one representing a pollinator that is mutualistic at the adult stage but antagonistic at the larval stage, and the other representing a non-structured pest herbivore. Our model revealed that environmental stresses (increasing insect mortality) can have counterintuitive effects on plants. Nonetheless, plant abundance generally decreases with decreasing pollinator abundance, especially when plant populations grow slowly without pollinators, when pollinators are effective mutualists, or when pollinators are susceptible to environmental stresses. These findings offer a theoretical basis for assessing the pollinator crisis for biodiversity conservation and agricultural management.

Pineapple growth and development modeling based on nitrogen rate and planting density

Plant growth models, derived from reliable databases, enable development of software for recommending cultural practices, harvest predictions, and enhancing productivity. This study aimed to create, refine, and simulate reference models for pineapple growth and development, adapting them based on nitrogen supply per plant and plant density per hectare. We utilized a field test database with periodic assessments of root, stem, leaf, fruit, and stem diameter fresh and dry weight, along with climate data from meteorological stations in or near the experimental areas. These growth models were developed, considering significant correlations and high correlation coefficients, using both simple non-destructive (stem diameter) and destructive (fresh or dry weight of D leaf) plant evaluations, either separately or in combination. The resulting models can provide estimated predictions for pineapple growth, adaptable to varying plant populations and nitrogen fertilization rates (measured in grams of N per plant)

A call to action for inventorying and monitoring of cliff ecosystems to support conservation

Cliffs harbor unique and specialized biodiversity that warrants attention and conservation. At the same time, cliffs are under increased threat from anthropogenic disturbance and climate change. Since cliffs are highly heterogeneous, spatially isolated, and often inaccessible compared to nearby habitats, land managers require up-to-date and site-specific information to protect them. Cliffs are often overlooked due to the technical and logistical challenges posed by surveying these environments, but field inventorying and monitoring can fill this gap. We present three case studies of cliff monitoring in action: mapping populations of an endemic rare plant in the Southern Appalachian Mountains (US), photo-sampling of cliff specialist plants in Spain, and surveying peregrine falcons in Western North Carolina (US). These case studies highlight the application of various monitoring techniques, the possibilities for collaboration among stakeholders, and some ways that data from monitoring can inform cliff conservation and stewardship. To facilitate the development of easy-to-implement monitoring, we outline three approaches and associated best practices for monitoring cliff plants. Methods range from simple photo point monitoring to more in-depth species inventories and could be implemented by community scientists alongside a broader audience interested in providing up-to-date data on cliff environments. We call for action, urging the expansion and advancement of cliff biodiversity monitoring.

The frequency and chemical phenotype of neighboring plants determine the effects of intraspecific plant diversity.

Associational effects, whereby plants influence the biotic interactions of their neighbors, are an important component of plant-insect interactions. Plant chemistry has been hypothesized to mediate these interactions. The role of chemistry in associational effects, however, has been unclear in part because the diversity of plant chemistry makes it difficult to tease apart the importance and roles of particular classes of compounds. We examined the chemical ecology of associational effects using backcross-bred plants of the Solanum pennellii introgression lines. We used eight genotypes from the introgression line system to establish 14 unique neighborhood treatments that maximized differences in acyl sugars, proteinase inhibitor, and terpene chemical diversity. We found that the chemical traits of the neighboring plant, rather than simply the number of introgression lines within a neighborhood, influenced insect abundance on focal plants. Furthermore, within-chemical class diversity had contrasting effects on herbivore and predator abundances, and depended on the frequency of neighboring plant chemotypes. Notably, we found insect mobility-flying versus crawling-played a key role in insect response to phytochemistry. We highlight that the frequency and chemical phenotype of plant neighbors underlie associational effects and suggest this may be an important mechanism in maintaining intraspecific phytochemical variation within plant populations.

Accumulation of pathogens in soil microbiome can explain long-term fluctuations of legumes in a grassland community.

All plant populations fluctuate in time. Apart from the dynamics imposed by external forces such as climate, these fluctuations can be driven by endogenous processes taking place within the community. In this study, we aimed to identify potential role of soil-borne microbial communities in driving endogenous fluctuations of plant populations. We combined a unique, 35-yr long abundance data of 11 common plant species from a species-rich mountain meadow with development of their soil microbiome (pathogenic fungi, arbuscular mycorrhizal fungi and oomycetes) observed during 4 yr of experimental cultivation in monocultures. Plant species which abundance fluctuated highly in the field (particularly legumes) accumulated plant pathogens in their soil mycobiome. We also identified increasing proportion of mycoparasitic fungi under highly fluctuating legume species, which may indicate an adaptation of these species to mitigate the detrimental effects of pathogens. Our study documented that long-term fluctuations in the abundance of plant species in grassland communities can be explained by the accumulation of plant pathogens in plant-soil microbiome. By contrast, we found little evidence of the role of mutualists in plant population fluctuations. These findings offer new insights for understanding mechanisms driving both long-term vegetation dynamics and patterns of species coexistence and richness.

Study of Genetic Variability and Character Association for Yield and Components Traits in Chickpea (Cicer arietinum L.) Germplasm in Bundelkhand Region

Chickpea (Cicer arietinum L.) is a very important crop among the grain legume crops in India. It is grown in north India in the winter season on marginal and semi-marginal land as a commonly non-irrigated crop. Bundelkhand, a region in Uttar Pradesh, India, is notorious for its harsh climate, characterized by extreme heat and drought stress. Temperature fluctuate with highs reaching 50°C in summer and lows of 5°C in winter, exert substantial adverse effects on chickpea cultivation, impairing crop growth and yield and demand to have genetic resources used in breeding programs. The experiment aimed to characterize and evaluate 204 chickpea lines, including commercial varieties, to understand the magnitude of variability and the association of various yield parameters on the yield of chickpea based on 12 agro-morphological characters under Bundelkhand region. ANOVA shows that significant variation exists for most of the characteristics of chickpeas. Higher GCV and PCV were observed for plant population (GCV 24.92, PCV 31.22) followed by the number of secondary branches (GCV 21.61, PCV 26.55), number of pods per plant (GCV 12.92, PCV 18.47), seed yield per plant (GCV 11.39, PCV 21.98) and biological yield per plant (GCV 11.68, PCV 20.37), revealing that the environment plays a positive role in the expression of these characters. High heritability was found by 100 seed weight (96.41) followed by seed yield per plant (84.11) and number of pods per plant (66.26) and a high degree of genetic advance was found in the number of pods per plant (26.24) followed by biological and seed yield per plant (15.25 and 6.92). High heritability coupled with high genetic advance was found in seed yield per plant, followed by biological yield per plant, indicating selection could be rewarding in proper breeding programs. Correlation and path studies showed that biological yield per plant (r-0.91), number of pods per plant (r- 0.680), number of secondary branches per plant (r-0.46), number of seeds per pod (r-0.32) and 100 seed weight (0.29) turned out to be the main components for seed yield per plant in chickpea, stipulating that these characters could be desirable selection parameter.

Climatic variation allows montane willows to escape an adaptive trade-off.

Adaptive responses to climate change, based on heritable variation in stress tolerance, may be important for plant population persistence. It is unclear which populations will mount the strongest future adaptive responses. It may be fruitful to identify populations that have escaped trade-offs among performance traits, which can hinder adaptation. Barring strong genetic constraints, the extent of trade-offs may depend on spatial relationships among climate variables shaping different traits. Here, we test for climate-driven ecotypic variation and trade-offs among drought and freezing sensitivity, and growth, for Lemmon's willow (Salix lemmonii) in a common garden study of 90 genotypes from 38 sites in the Sierra Nevada, USA. Salix lemmonii exhibits ecotypic variation in leaf turgor loss point, a measure of drought sensitivity, from -0.95 to -0.74 MPa along a gradient of spring snowpack. We also find variation in spring freezing sensitivity with minimum May temperature. However, we find no trade-off, as the climatic gradients shaping these traits are spatially uncorrelated in our study region, despite being negatively correlated across the Sierra Nevada. Species may escape adaptive trade-offs in geographic regions where climate variables are spatially decoupled. These regions may represent valuable reservoirs of heritable adaptive phenotypic variation.

When is lethal deceptive pollination maintained? A population dynamics approach.

Not all plant-pollinator interactions are mutualistic, and in fact, deceptive pollination systems are widespread in nature. The genus Arisaema has a pollination system known as lethal deceptive pollination, in which plants not only attract pollinating insects without providing any rewards, but also trap them until they die. Many Arisaema species are endangered from various disturbances including reduction in forest habitat, modification of the forest understory owing to increasing deer abundance, and plant theft for horticultural cultivation. We aimed to theoretically investigate how lethal deceptive pollination can be maintained from a demographic perspective and how plant and pollinator populations respond to different types of disturbance. We developed and analysed a mathematical model to describe the population dynamics of a deceptive plant species and its victim pollinator. Calibrating the model based on empirical data, we assessed the conditions under which plants and pollinators could coexist, while manipulating relevant key parameters. The model exhibited qualitatively distinct behaviours depending on certain parameters. The plant becomes extinct when it has a low capability for vegetative reproduction and slow transition from male to female, and plant-insect co-extinction occurs especially when the plant is highly attractive to male insects. Increasing deer abundance has both positive and negative effects because of removal of other competitive plants and diminishing pollinators, respectively. Theft for horticultural cultivation can readily threaten plants whether male or female plants are frequently collected. The impact of forest habitat reduction may be limited compared to that of other disturbance types. Our results have emphasised that the demographic vulnerability of lethal deceptive pollination systems would differ qualitatively from that of general mutualistic pollination systems. It is therefore important to consider the demographics of both victim pollinators and deceptive plants to estimate how endangered Arisaema populations respond to various disturbances.