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Data for: Shifts in plant-invertebrate interactions between wild and ex-situ conservation populations of a critically endangered tree

Ex-situ conservation is an effective approach to prevent the extinction of endangered species. Biotic interactions (eg herbivory and pollination) are critical to ex-situ conservation success, including plant establishment, survival, and reproduction. However, shifts in biotic interactions between wild and ex-situ populations are still poorly understood. We compared herbivory and pollination characteristics between the only wild population (WP) and three ex-situ populations (LP, local population, nearby WP; NP, north population, ca. 850 km; and SP, south population, ca. 750 km) of a critically endangered tree species (Sinojackia huangmeiensis) to explore the latitudinal changes in plant-invertebrate interactions. Larvae of the Limacodidae family were the dominant herbivores in WP, LP, and NP, while the only herbivore observed in SP was a snail. Compared to WP, the leaf herbivory rate was unchanged in LP but decreased in NP and SP. Leaf defense traits (total phenols, tannins, leaf thickness, and leaf dry matter content) increased or remained unchanged in the three ex-situ populations. A pollinator (Apis cerana) of S. huangmeiensis was present in the four populations. NP and SP lacked some pollinators that were found in both WP and LP, but they shared one pollinator that was not observed in WP and LP. The pollinator visiting frequency increased in SP, while it did not change significantly in LP and NP. Synthesis and applications: Our results suggested that both herbivory and pollination of S. huangmeiensis changed in ex-situ populations, with complete or partial changes in herbivores, leaf herbivory rate, pollinators, pollinator visiting frequency, and fruit set in the two distant ex-situ populations. This work provides a unique empirical study of shifts in both antagonistic and mutualistic biotic interactions between wild and ex-situ populations. We emphasized that it is essential to integrate herbivore and pollinator management in future ex-situ conservation of plant species.

Beyond a single temperature threshold: applying a cumulative thermal stress framework to plant heat tolerance

Most plant thermal tolerance studies focus on single critical thresholds, which limit the capacity to generalise across studies and predict heat stress under natural conditions. In animals and microbes, thermal tolerance landscapes describe the more realistic, cumulative effects of temperature. We tested this in plants by measuring the decline in leaf photosynthetic efficiency (FV/FM) following a combination of temperatures and exposure times, then modelled these physiological indices alongside recorded environmental temperatures. We demonstrate that a general relationship between stressful temperatures and exposure durations can be effectively employed to quantify and compare heat tolerance within and across plant species and over time. Importantly, we show how FV/FM curves translate to plants under natural conditions, suggesting that environmental temperatures often impair photosynthetic function. Our findings provide more robust descriptors of heat tolerance in plants and suggest that heat tolerance in disparate groups of organisms can be studied with a single predictive framework.

Meta-analysis of the effects of abiotic factors on plant microbes

The abiotic environment exerts strong effects on plant-associated microbes, shaping their interactions with plants and resulting ecosystem processes. However, these abiotic effects on plant-microbe interactions are often highly specific and contingent on the abiotic driver or microbial group, requiring synthesis work describing general patterns and from this generate hypotheses and guide mechanistic work. To address this, we conducted a meta-analysis of the effects of climate change-related abiotic factors, namely warming, drought, and eCO2, on plant-associated microbes distinguishing by microbial taxonomic or biological group (bacteria, fungi or virus) and the plant part where microbes are found or associated with (phyllosphere or rhizosphere). We found abiotic driver-specific patterns, whereby drought significantly reduced microbial abundance, whereas warming and eCO2 had no significant effects. In addition, these abiotic effects were contingent on the microbial taxonomic group, with fungi being negatively affected by drought but positively affected by warming (eCO2 enrichment had no effect), whereas bacteria and viruses were not significantly affected by any factor. Likewise, rhizopheric microbes were negatively affected by drought but positively affected by warming (eCO2 enrichment had no effect), whereas phyllospheric microbes were not significantly affected by any factor. Collectively, these findings point to important implications for global change research by highlighting contrasting effects of climate change-related abiotic drivers on plant-associated microbes and the contingency of such effects on microbe life histories and the nature of their interactions with plants.

Data from: Pace and parity predict short-term persistence of small plant populations

Life history traits are used to predict asymptotic odds of extinction from dynamic conditions. Less is known about how life history traits interact with stochasticity and population structure of finite populations to predict near-term odds of extinction. Through empirically parameterized matrix population models, we study the impact of life history (reproduction, pace), stochasticity (environmental, demographic), and population history (existing, novel) on the transient population dynamics of finite populations of plant species. Among fast and slow pace and either uniform or increasing reproductive intensity or short or long reproductive lifespan, slow, semelparous species are at the greatest risk of extinction. Long reproductive lifespans buffer existing populations from extinction while the odds of extinction of novel populations decreases when reproductive effort is uniformly spread across the reproductive lifespan. Our study highlights the importance of population structure, pace, and two distinct aspects of parity for predicting near-term odds of extinction.

opencc-by-nd-4.0Apr 2023View details →

Figure 3 in Where there are ants, there are ant mimics: occurrence of jumping spiders that mimic ants on the castor plant across India

Figure 3. Non-mimicking salticids observed on castor plants. A, J Thyene imperialis (Rossi, 1846). B, Immature Carrhotus viduus (C. L. Koch, 1846), a species known to associate with ants (Hill et al., 2021; Khalap & Hill, 2022). C, ♀ Hyllus semicupreus (Simon, 1885). D, Madhyattus sp.

opencc-by-nd-4.0Apr 2023View details →

Figure 2 in Where there are ants, there are ant mimics: occurrence of jumping spiders that mimic ants on the castor plant across India

Figure 2. Ant-mimicking jumping spiders observed during our sampling of castor plants across India (associated ant species, or hypothetical models, in parentheses). A, Myrmarachne melanocephala female (Tetraponera rufonigra), Ramnagar. B, ♀ Myrmarachne sp. (Camponotus sericeus), Kanyakumari. C, ♀ Myrmaplata plataleoides (Oecophylla smaragdina), Hampi. D, J Myrmarachne kuwagata (Camponotus compressus), Aligarh. E, ♀ Myrmarachne sp. (Crematogaster sp.), Srirangam. F, ♀ Myrmarachne kuwagata female drinking nectar from an extrafloral nectary on a castor plant, Ricinus communis, Gwalior. Photographs by Pooja Nathan.

opencc-by-4.0Jul 2023View details →

Figure 3 in Aculus taihangensis (Acari: Prostigmata: Eriophyidae), a potential biological control agent identified from the highly invasive pest plant, tree of heaven, in Türkiye

Figure 3. Aculus taihangensis – Deutogyne: A. Coxigenital region, B. Internal genitalia.

Data from: Plant-soil interactions during the native and exotic range expansion of an annual plant

Range expansions, whether they are biological invasions or climate change-mediated range shifts, may have profound ecological and evolutionary consequences for plant-soil interactions. Range-expanding plants encounter soil biota with which they have a limited coevolutionary history, especially when introduced to a new continent. Past studies have found mixed results on whether plants experience positive or negative soil feedback interactions in their novel range, and these effects often change over time. One important theoretical explanation is that plants locally adapt to the soil pathogens and mutualists in their novel range. We tested this hypothesis in Dittrichia graveolens, an annual plant that is both expanding its European native range, initially coinciding with climate warming, and rapidly invading California, after human introduction. In parallel greenhouse experiments on both continents, we used plant genotypes and soils from five locations at the core and edge of each range to compare plant growth in soil from D. graveolens populations and nearby control microsites as a measure of plant-soil feedback. Plant-soil interactions were highly idiosyncratic across sites in each range. On average, plant-soil feedbacks were more positive in the native range than in the exotic range. In line with the strongly heterogeneous pattern of soil responses along our biogeographic gradients, we found no evidence for evolutionary differentiation between plant genotypes from the core to the edge of either range. Our results suggest that the evolution of plant-soil interactions during range expansion may be more strongly driven by local evolutionary dynamics varying across the range than by large-scale biogeographic shifts.

Data and code from: Similar trait-based successional assembly in native and introduced plants despite species pool differences

What drives the composition of invaded communities and the local abundance of introduced species are key questions in ecology. Community-assembly theory provides a useful framework for addressing these questions. Specifically, the environmental filtering model of community assembly predicts that a species' presence and abundance in a community depends on the interaction between its functional traits and the local environmental filters. However, for introduced species, larger-scale dispersal and introduction-related filters may restrict their regional trait pool. Here we tested this framework using long-term data from 50+ years of old-field vegetation succession. We asked whether native and introduced plant assemblages followed the same trait-based assembly rules. We also asked whether local functional dissimilarities between the two can be explained by regional species pool differences, a possibility that has rarely been addressed. We found strong similarities in the assembly processes of native and introduced plants. Average height and seed mass of both groups increased over time, consistent with previous studies of old-field succession. Moreover, the two showed similar trait-abundance relationships. While there were also some differences, particularly in their trait-incidence relationships, these differences appeared to be minor.Further, we identified species pool constraints on introduced species, and found that the exotic species pool was biased towards early successional traits. Lastly, we found that highly invasive exotic species were also likely to deviate from the expected trait-abundance relationship, suggesting a link between the two. These results suggest that introduced species generally follow the same assembly rules as native species. They also indicate that species pool differences can result in local functional composition differences, even when the two groups follow the same assembly rules. Moreover, there may be a link between species invasiveness and deviation from assembly rules, which, if further confirmed, provides a potential method of identifying strong invaders.

opencc-by-4.0Mar 2024View details →

Dutch landscapes have lost insect-pollinated plants over the past 87 years

Data associated with the publication "Dutch landscapes have lost insect-pollinated plants over the past 87 years". Abstract: 1. The interruption of plant-pollinator interactions may threaten global plant diversity, food security, and ecosystem stability. Recent reports of strong declines in both insects and plants point to insect decline as a driver of plant decline. However, it is still unknown whether these trends are related as plants often produce seeds without the need for insect pollinators, and to what extent insect-pollinated plants have declined in relation to plants not pollinated by insects. 2. In this study, we hypothesise that natural plant communities have shifted away from insect-pollination. We combined 365,768 vegetation plots from 1930 to 2017 in the Netherlands and plant traits to assess the changes in occurrences of plants pollinated by different modes. Furthermore, we included key drivers in plant decline—specifically nitrogen, moisture, and habitat types—as interaction factors to explore the persistence of the observed changes under different environmental conditions. 3. The proportion of insect-pollinated plants has declined while that of wind-pollinated plants has increased over the last 87 years. This proportional change reflects an absolute decrease in the number of insect-pollinated species and an increase in the number of wind-pollinated species. 4. Synthesis and applications. This study implies that Dutch landscapes are losing insect-pollinated plant species, which is likely due, at least in part, to the decline in pollination services. Our results of quantifying the decline in insect-pollinated plants support the necessity and urgency of taking conservation initiatives. Several management strategies and policy recommendations could be applied to alleviate the decline of insect-pollinated plants and ensure crop safety. For example, conserving natural environments by reducing nitrogen deposition may support local plants and insect pollinators. Additionally, there is a particular need for focused efforts to protect natural grasslands, as these areas harbor many insect-pollinated plants, which have experienced declines. Finally, monitoring and assessing the state of both pollinators and (insect-pollinated) plants is needed to assess the progress of conservation measures. While recognizing the interdependence of pollinators and pollinated plants, it is crucial to extend efforts beyond pollinator conservation alone to effectively safeguard insect-pollinated plants and ensure crop safety.

Data from: Far red light increases maize volatile emissions in response to volatile cues from neighboring plants

Plants perceive the presence and defense status of their neighbors through light and volatile cues, but how plants integrate both stimuli is poorly understood. We investigated if and how low Red to Far red light (R:FR) ratios, indicative of shading or canopy closure, affect maize (Zea mays) responses to herbivore-induced plant volatiles (HIPVs), including the green leaf volatile (Z)-3-hexenyl acetate. We modulated light signaling and perception by using FR supplementation and a phyB1phyB2 mutant, and we determined volatile release as a response readout. To gain mechanistic insights, we examined expression of volatile biosynthesis genes, hormone accumulation, and photosynthesis. Exposure to a full blend of HIPVs or (Z)-3-hexenyl acetate induced maize volatile release. Short-term FR supplementation increased this response. In contrast, prolonged FR supplementation or constitutive phytochrome B inactivation in phyB1phyB2 plants showed the opposite response. Short-term FR supplementation enhanced photosynthesis and stomatal conductance and (Z)-3-hexenyl acetate-induced JA-Ile levels. We conclude that a FR-enriched light environment can prompt maize plants to respond more strongly to HIPVs emitted by neighbors, which might be explained by changes in photosynthetic processes and phytochrome B signaling. Our findings reveal interactive responses to light and volatile cues with potentially important consequences for plant-plant and plant-herbivore interactions.

Effective dispersal patterns in prairie plant species across human-modified landscapes

Effective dispersal among plant populations is dependent on vector behavior, landscape features, and availability of adequate habitats. To capture landscape feature effects on dispersal, studies must be conducted at scales reflecting single-generation dispersal events (meso-scale). Many studies are conducted at large-scales where genetic differentiation is due to dispersal occurring over multiple generations, making it difficult to interpret the effects of specific landscape features on vector behavior. Genetic structure at the meso-scale may be determined by ecological and evolutionary processes, such as the consequences of vector behavior on patterns of gene flow. We used chloroplast haplotypes and nuclear genome SNP surveys to identify landscape features influencing seed and pollen dispersal at a meso-scale within the Rogue River Valley in southern Oregon. We evaluated biotic and abiotic vector behavior by contrasting two annual species with differing dispersal mechanisms; Achyrachaena mollis (Asteraceae) is a self-pollinating and anemochoric species, and Plectritis congesta (Caprifoliaceae) is biotically pollinated with barochoric seeds. Using landscape genetics methods, we identified features of the study region that conduct or restrict dispersal. We found chloroplast haplotypes were indicative of historic patterns of gene flow prior to human modification of landscapes. Seed dispersal of A. mollis was best supported by models of isolation-by-distance, while seed-driven gene flow of P. congesta was determined by the distribution of preserved natural spaces and quality habitat. Whole-genome genetic structure was driven by both pollen and seed dispersal, and both species responded to contemporary landscape changes, such as urban and agricultural conversion, and habitat availability.

Sites dominated by common fiddleneck (Amsinckia menziesii var. intermedia) support diverse plant-pollinator interactions

Biodiversity is declining at unprecedented rates worldwide due largely to land use change and abnormal disturbance events. The high species diversity and endemicity found in California's coastal sage scrub (CSS) are especially at risk from urban development and ongoing disturbance. However, several CSS plant species have disturbance adaptations which may allow them to serve as vital resources for insect pollinators when native plant diversity is threatened. Common fiddleneck (Amsinckia menziesii var. intermedia) is one of the first annual forbs to germinate in CSS and as a result, it occurs in high density patches in early spring which temporarily creates a near monoculture. Although fiddleneck is a prominent CSS plant, particularly in areas that have experienced a disturbance event, its larger ecological role is not well explored. Therefore, we monitored ten sites across a disturbance gradient for two spring seasons to assess the composition of plant-pollinator networks in fiddleneck-dominated plots. We found fiddleneck supported a diverse pollinator community with 68% of recorded taxa visiting fiddleneck. The plants most frequently visited included two native annual forbs (common fiddleneck and Phacelia distans) and two invasive annual forbs (Erodium cicutarium and Brassica tournefortii). Plant and pollinator abundances increased with increased mean precipitation. Additionally, plant-pollinator networks changed over time; the number of links per species increased throughout the season but did not differ amongst disturbance types. Despite the numerical dominance of fiddleneck, CSS supported a diversity of pollinator taxa and exhibited complex plant-pollinator networks across the disturbance gradient.

Incorporating plant phenological responses into species distribution models (SDMs) reduces estimates of future species loss and turnover

Anthropogenetic climate change has caused distribution shifts of many species, and species distribution models (SDMs) are central for documenting this relationship. However, most SDMs rarely consider the evolution of climate-sensitive functional traits, such as phenology, which strongly affect species fitness. Using >120,000 herbarium specimens representing 360 plant species across the eastern United States, we developed a novel "phenology-informed" SDM that integrates dynamic phenological responses to changing climates. Compared to standard SDMs, our phenology-informed SDMs forecast lower species habitat loss and less species turnover under climate change. These results suggest that phenotypic plasticity or local adaptation in phenology may help species adjust their ecological niches and persist in their habitats under rapid environmental change. Our findings reveal how phenology variation mediates species distributions and affects regional biodiversity patterns. Our newly developed model also circumvents the need for mechanistic models, facilitating the deployment of trait-based SDMs across unprecedented spatial and taxonomic scales.

Alien plant species are precursors for invasion: a case study of Alternanthera brasiliana (L.) Kuntze in Ile-Ife (Nigeria)

The impact of Alternanthera brasiliana on vegetation and soil seed bank was assessed in Ile-Ife, Nigeria. Ten sample plots, 10 m x 10 m each, were established in invaded plant communities with high density of Alternanthera brasiliana and adjacent uninvaded plant communities where the weed species has low density. In each sample plot, twenty 1 m x 1 m quadrats were randomly laid and all rooted plant species were identified and counted. Post-dispersal soil seed bank was collected by randomly taking five core samples of top soil per sample plot to estimate the soil seed bank density and floristics of the sites. The species composition of soil seed bank was compared with that of the above-ground vegetation so as to assess the invader's impact on the vegetation using Sorensen's index of similarity. The results showed that Alternanthera brasiliana invasion significantly impacted on the species diversity (t = 5.27; df = 18; p = 0.0003) and evenness of species distribution (t = 4.50; df = 18; p = 0.00005) in the aboveground vegetation, and the species diversity (t = 5.37; df = 18; p = 0.00004) and evenness of species distribution (t = 6.19; df = 18; p < 0.0001) in the soil seed bank. This study concluded that Alternanthera brasiliana has significantly caused alterations in key parameters of the aboveground vegetation and those of the soil seed bank. It is likely that with increasing resident time, these alterations might increase more significantly to enhance the spread of Alternanthera brasiliana.

Deer grazing drove an assemblage-level evolution of plant dwarfism in an insular system

Plant dwarfism, a syndrome characterised by a significant reduction in plant height and organ size, is a widely observed pattern of stress-tolerant life-form evolution that results from local adaptation to harsh environmental conditions. The drivers of assemblage-level dwarfism have primarily been attributed to abiotic factors, such as low temperature, aridity, poor soil fertility, or frequent fires. While biotic factors such as grazing pressure from herbivores can contribute to the establishment of plant dwarfism, these factors have rarely been tested at assemblage levels. Focusing on a dwarf plant assemblage comprising over 80 taxa on a small continental island in Japan with a high deer density, we hypothesised that historical deer grazing could also be a factor contributing to the large-scale convergent evolution of dwarfism. To test this hypothesis, we measured the size of 1,908 individual plants of 40 taxa-pairs, comprising both palatable and unpalatable pairs from the island and their counterpart taxa from neighbouring regions, and sought to assess which factors (i.e. low solar radiation, estimated divergence time, low nutrient conditions, and grazing pressure from deer) may have contributed to the formation of the dwarf plant assemblage on the island. We also performed genetic analysis to infer the timeframes for the establishment of dwarf taxa. Statistical analyses revealed that plant size was significantly reduced mainly among the palatable taxa growing on the island, with preferential grazing by deer being identified as the most significant factor influencing plant size. Furthermore, genetic analyses revealed that dwarf ecotypes may have evolved over tens of thousands of years. Synthesis: To the best of our knowledge, this study is the first to demonstrate that interactions with herbivores can shape the assemblage-level convergence of plant dwarfism. These findings enhance our current understanding of the formation of plant functional diversity.

opencc-by-4.0Apr 2024View details →

Data and code for : 'Interactive effects of temperature, aridity, and plant stoichiometry on insect herbivory: past and present', The American Naturalist

The files are for the manuscript 'Interactive effects of temperature, aridity, and plant stoichiometry on insect herbivory: past and present' consist of the following major parts:   1.     FILE “all site summary.xlsx”: Summary data of all the fossil sites used in the study. This is an MS Excel file and has three sheets, namely: a.     All_sites: This sheet lists various metadata related to each of the 39 fossil sites used in this study. The name of the site is listed as ‘Flora’, and each site has the following data associated with it: Epoch, Latitude Bin, Region, Geographic location, Lat(itude), Long(itude), Depositional.Environment, Age, Age.error, MAT.C (Mean Annual Temperature in degrees C), MAT.Error, MAP.mm.yr (Mean Annual Precipitation in mm), MAP.error, and No.Leaves (number of leaf specimens). b.     PEB sites list (Bighorn): This sheet specifically lists the 8 Paleocene-Eocene boundary (PEB) sites from the Bighorn basin along with relevant metadata. These sites are also present in the All_sites tab. c.     PEB sites list (Hanna): This sheet lists the 2 Hanna Basin sites from the PEB with relevant metadata. 2.     FOLDER “fossil site herbivory data”: This folder contains the leaf-level herbivory data from all the fossil sites used in this study (including the PEB sites from Hanna Basin) in .csv format. Each file has the following data structure: the first column lists the morphotaxa name of the leaf and the subsequent columns represent whether a particular DT (Damage Type, represented by individual column names) is present (1) or absent (0/NA) in that leaf. 3.     FOLDER “modern site herbivory data”: This folder contains the leaf-level level herbivory data from all the modern sites used in this study in .txt format. “presab_data_HFmatrix” is the data from the three sites in Harvard Forest, “presab_data_LSmatrix” from three sites in La Selva and “presab_data_SERCmatrix” from the three sites in the Smithsonian Environmental Research Center. The quarry number is the name of the site in each file. The rest of the structure is same as fossil data: the second column lists the taxa name for the leaf and the subsequent columns represent whether a particular DT (Damage Type, represented by individual column names) is present (1) or absent (0/NA) in that leaf. 4.     FOLDER “masks for FFGs”: This folder has two files, namely: a.     “ffgdef_DT.csv”: This file lists which Functional Feeding Group does each DT belong to. Oviposition =0, Skeletonization=1, Surface feeding =2, Galling=3, Hole Feeding=4, Mining =5, Margin Feeding =6,  Piercing and Sucking=7. b.    “mask_DT.csv”: This file lists whether a given DT is a herbivory damage, a specialized damage, gall or mining damage (T/F). 5.     FOLDER “N2_fixing_site_level_taxa”: This folder contains 8 files in .csv format corresponding to each of the 8 PEB Bighorn Basin sites. Each file has the same structure: the first column corresponds to a specific morphotaxa and the next column indicates whether it is a N2 fixing plant (1) or not (0). 6. FILE "Analyais_base.Rmd" gives base code to replicate all the results.

opencc-zeroDec 2023View details →

Roadside disturbance promotes plant communities with arbuscular mycorrhizal associations in mountain regions worldwide

Aim: We aimed to assess the impact of road disturbances on the dominant mycorrhizal types in ecosystems at the global level and how this mechanism can potentially lead to lasting plant community changes. Location: Globally distributed mountain regions Time Period: 2007-2018 Taxa studied: Plants (linked to their associated mycorrhizal fungi) Methods: We used a database of coordinated plant community surveys following mountain roads from 894 plots in 11 mountain regions across the globe in combination with an existing database of mycorrhizal-plant associations in order to approximate the relative abundance of mycorrhizal types in natural and disturbed environments. Results: Our findings show that roadside disturbance promotes the cover of plants associated with arbuscular mycorrhizal (AM) fungi. This effect is especially strong in colder mountain environments and in mountain regions where plant communities are dominated by ectomycorrhizal (EcM) or ericoid-mycorrhizal (ErM) associations. Furthermore, non-native plant species, which we confirmed to be mostly AM plants, are more successful in environments dominated by AM associations. Main Conclusions: These biogeographical patterns suggest that changes in mycorrhizal types could be a crucial factor in the worldwide impact of anthropogenic disturbances on mountain ecosystems. Indeed, roadsides foster AM-dominated systems, where AM-fungi might aid AM-associated plant species while potentially reducing the biotic resistance against invasive non-native species, often also associated with AM networks. Restoration efforts in mountain ecosystems will have to contend with changes in the fundamental make-up of EcM- and ErM plant communities induced by roadside disturbance.

opencc-zeroApr 2024View details →

Data from: Land-use intensity and relatedness to native plants promote exotic plant invasion in a tropical biodiversity hotspot

Exotic plant invasions threaten biodiversity and are costly to farmers. Land use is a major pathway promoting the spread of exotic plant species; however, little is known about the processes underlying the success of exotic plants in tropical agricultural landscapes. Focussing on the heterogeneous smallholder landscapes of north-eastern Madagascar, we studied exotic plants of understorey communities across a land-use intensity gradient from unburned lands (old-growth forests, forest fragments, and forest-derived vanilla agroforests) to burned ones (fallow-derived vanilla agroforests, woody fallows, and herbaceous fallows). We quantified the absolute species richness, abundance, and cover of exotic plants across land-use types and their proportional contribution to community richness, abundance, and cover as indicators of exotic plant invasion. We tested for the effects of land-use parameters, namely land-use history, canopy closure, and landscape-level forest cover, on exotic plants. Additionally, we tested whether the phylogenetic relatedness between exotic and native species in the same plot affected invasion success, testing Darwin's naturalization and pre-adaptation hypotheses. All indicators of exotic plant invasion were lowest in old-growth forests and forest fragments and highest in fallow-derived vanilla agroforests, woody fallows, and herbaceous fallows. Absolute and proportional exotic richness was negatively affected by canopy closure, and landscapes with high forest cover had lower proportions of exotic plant richness. High phylogenetic relatedness between exotics and natives was associated with lower proportional richness but higher proportions of exotics in abundance and cover. However, individual exotic species showed contrasting responses to land-use parameters and relatedness to natives. Synthesis and applications: Our results indicate that maintaining unburned lands, land-use types with dense canopies, and landscapes with high forest cover prevents the spread of exotic plants within agricultural landscapes of north-eastern Madagascar. Supporting Darwin's pre-adaptation hypothesis, exotic plants phylogenetically closely related to native plants are more likely to become successful invaders in terms of abundance and cover. Nevertheless, individual species show different responses to land-use changes and phylogenetic relatedness. Therefore, land-use decisions and management choices can be tailored to limit the spread of exotic species and to preserve native plants in this global biodiversity hotspot.