Conversion of sagebrush shrublands to exotic annual grasslands negatively impacts small mammal communities

Aim The exotic annual cheatgrass (Bromus tectorum) is fast replacing sagebrush (Artemisia tridentata) communities throughout the Great Basin Desert and nearby regions in the Western United States, impacting native plant communities and altering fire regimes, which contributes to the long‐term persistence of this weedy species. The effect of this conversion on native faunal communities remains largely unexamined. We assess the impact of conversion from native perennial to exotic annual plant communities on desert rodent communities. Location Wyoming big sagebrush shrublands and nearby sites previously converted to cheatgrass‐dominated annual grasslands in the Great Basin Desert, Utah, USA. Methods At two sites in Tooele County, Utah, USA, we investigated with Sherman live trapping whether intact sagebrush vegetation and nearby converted Bromus tectorum‐dominated vegetation differed in rodent abundance, diversity and community composition. Results Rodent abundance and species richness were considerably greater in sagebrush plots than in cheatgrass‐dominated plots. Nine species were captured in sagebrush plots; five of these were also trapped in cheatgrass plots, all at lower abundances than in the sagebrush. In contrast, cheatgrass‐dominated plots had no species that were not found in sagebrush. In addition, the site that had been converted to cheatgrass longer had lower abundances of rodents than the site more recently converted to cheatgrass‐dominated plots. Despite large differences in abundances and species richness, Simpson’s D diversity and Shannon‐Wiener diversity and Brillouin evenness indices did not differ between sagebrush and cheatgrass‐dominated plots. Main conclusions This survey of rodent communities in native sagebrush and in converted cheatgrass‐dominated vegetation suggests that the abundances and community composition of rodents may be shifting, potentially at the larger spatial scale of the entire Great Basin, where cheatgrass continues to invade and dominate more landscape at a rapid rate.     

荒漠啮齿动物群落对开垦干扰的响应及其种群生态对策

开垦对功能相对脆弱的荒漠生态系统是重要的干扰,这种干扰往往导致栖息地破碎化,并对动植物群落产生强烈影响。作为荒漠生态系统的重要成分,啮齿动物群落受到开垦干扰后对环境的响应及其群落中种群的生态对策,是荒漠生态系统生物多样性及其功能维持稳定的重要基础。2006～2011年,采用标志重捕法对内蒙古阿拉善荒漠区未开垦和开垦草地啮齿动物群落格局及其不同生态对策种群的数量组成进行了专门研究。目的（1）明确开垦干扰下啮齿动物群落格局时间尺度变化;（2）验证假设：人为干扰区（开垦区）啮齿动物群落中r?对策者占据优势,未干扰区（未开垦区）以K?对策者为主;（3）依据啮齿动物群落中不同生态对策种群的数量组成来判断群落所受干扰的程度。结果表明,开垦干扰降低了啮齿动物群落多样性,改变了群落中不同生态对策种群的数量组成,种群以r?对策者为优势;未开垦区啮齿动物群落中以K?对策种群为主。开垦区啮齿动物群落受到严重干扰。     

Site‐specific responses of foliar fungal microbiomes to nutrient addition and herbivory at different spatial scales

The plant microbiome can affect host function in many ways and characterizing the ecological factors that shape endophytic (microbes living inside host plant tissues) community diversity is a key step in understanding the impacts of environmental change on these communities. Phylogenetic relatedness among members of a community offers a way of quantifying phylogenetic diversity of a community and can provide insight into the ecological factors that shape endophyte microbiomes. We examined the effects of experimental nutrient addition and herbivory exclusion on the phylogenetic diversity of foliar fungal endophyte communities of the grass species Andropogon gerardii at four sites in the Great Plains of the central USA. Using amplicon sequencing, we characterized the effects of fertilization and herbivory on fungal community phylogenetic diversity at spatial scales that spanned within‐host to between sites across the Great Plains. Despite increasing fungal diversity and richness, at larger spatial scales, fungal microbiomes were composed of taxa showing random phylogenetic associations. Phylogenetic diversity did not differ systematically when summed across increasing spatial scales from a few meters within plots to hundreds of kilometers among sites. We observed substantial shifts in composition across sites, demonstrating distinct but similarly diverse fungal communities were maintained within sites across the region. In contrast, at the scale of within leaves, fungal communities tended to be comprised of closely related taxa regardless of the environment, but there were no shifts in phylogenetic composition among communities. We also found that nutrient addition (fertilization) and herbivory have varying effects at different sites. These results suggest that the direction and magnitude of the outcomes of environmental modifications likely depend on the spatial scale considered, and can also be constrained by regional site differences in microbial diversity and composition.     

Negative Effects of an Exotic Grass Invasion on Small-Mammal Communities

Exotic invasive species can directly and indirectly influence natural ecological communities. Cheatgrass (Bromus tectorum) is non-native to the western United States and has invaded large areas of the Great Basin. Changes to the structure and composition of plant communities invaded by cheatgrass likely have effects at higher trophic levels. As a keystone guild in North American deserts, granivorous small mammals drive and maintain plant diversity. Our objective was to assess potential effects of invasion by cheatgrass on small-mammal communities. We sampled small-mammal and plant communities at 70 sites (Great Basin, Utah). We assessed abundance and diversity of the small-mammal community, diversity of the plant community, and the percentage of cheatgrass cover and shrub species. Abundance and diversity of the small-mammal community decreased with increasing abundance of cheatgrass. Similarly, cover of cheatgrass remained a significant predictor of small-mammal abundance even after accounting for the loss of the shrub layer and plant diversity, suggesting that there are direct and indirect effects of cheatgrass. The change in the small-mammal communities associated with invasion of cheatgrass likely has effects through higher and lower trophic levels and has the potential to cause major changes in ecosystem structure and function.     

Numerical responses of different trophic groups of invertebrates to manipulations of plant diversity in grasslands

We studied the effects of plant diversity on abundance of invertebrate herbivores, parasitoids and predators in two grassland communities (one in Switzerland and one in Sweden) in which plant species richness and functional diversity have been experimentally manipulated. Among herbivores, the abundance of only the most sessile and specialised groups (leafhoppers and wingless aphids) was affected by plant diversity. At both sites, numbers of leafhoppers in sweep net samples showed a linear, negative relationship with plant species number whereas numbers of wingless aphids in suction samples increased with the number of plant functional groups (grasses, legumes, and non-legume forbs) present in the plot. Activity of carabid beetles and spiders (as revealed by pitfall catches) and the total number of predators in pitfalls at the Swiss site decreased linearly with increases in the number of plant species and plant functional groups. Abundance of more specialised enemies, hymenopteran parasitoids, was not affected by the manipulations of plant diversity. Path analysis and analysis of covariance indicated that plant diversity effects on invertebrate abundance were mostly indirect and mediated by changes in plant biomass and cover. At both sites, plant species composition (i.e. the identity of plant species in a mixture) affected numbers of most of the examined groups of invertebrates and was, therefore, a more important determinant of invertebrate abundance in grasslands than plant species richness per se or the number of plant functional groups. The presence of legumes in a mixture was especially important and led to higher numbers of most invertebrate groups. The similarity of invertebrate responses to plant diversity at the two study sites indicates that general patterns in abundance of different trophic groups can be detected across plant diversity gradients under different environmental conditions.     

An unfortunate alliance: Native shrubs increase the abundance,performance, and apparent impacts of Bromus tectorum across a regional aridity gradient

Interspecific facilitation contributes to the assembly of desert plant communities. However, we know little of how desert communities invaded by exotic species respond to facilitation along regional-scale aridity gradients. These measures are essential for predicting how desert plant communities might respond to concomitant plant invasion and environmental change. Here, we evaluated the potential for Bromus tectorum (a dominant invasive plant species) and the broader herbaceous plant community to form positive associations with native shrubs along a substantial aridity gradient across the Great Basin, Mojave, and San Joaquin Deserts in North America. Along this gradient, we sampled metrics of abundance and performance for B. tectorum, all native herbaceous species combined, all exotic herbaceous species combined, and the total herbaceous community using 180 pairs of shrub and open microsites. Across the gradient, B. tectorum formed strong positive associations with native shrubs, achieving 1.6–2.2 times greater abundance, biomass, and reproductive output under native shrubs than away from shrubs, regardless of relative aridity. In contrast, the broader herbaceous community was not positively associated with native shrubs. Interestingly, increasing B. tectorum abundance corresponded to decreasing native abundance, native species richness, exotic species richness, and total species richness under but not away from shrubs. Taken together, these findings suggest that native shrubs have considerable potential to directly (by increasing abundance and performance) and indirectly (by increasing competitive effects on neighbors) facilitate B. tectorum invasion across a large portion of the non-native range.     

Negative per capita effects of two invasive plants, Lythrum salicaria and Phalaris arundinacea, on the moth diversity of wetland communities

Invasive plants have been shown to negatively affect the diversity of plant communities. However, little is known about the effect of invasive plants on the diversity at other trophic levels. In this study, we examine the per capita effects of two invasive plants, purple loosestrife (Lythrum salicaria) and reed canary grass (Phalaris arundinacea), on moth diversity in wetland communities at 20 sites in the Pacific Northwest, USA. Prior studies document that increasing abundance of these two plant species decreases the diversity of plant communities. We predicted that this reduction in plant diversity would result in reduced herbivore diversity. Four measurements were used to quantify diversity: species richness (S), community evenness (J), Brillouin's index (H) and Simpson's index (D). We identified 162 plant species and 156 moth species across the 20 wetland sites. The number of moth species was positively correlated with the number of plant species. In addition, invasive plant abundance was negatively correlated with species richness of the moth community (linear relationship), and the effect was similar for both invasive plant species. However, no relationship was found between invasive plant abundance and the three other measures of moth diversity (J, H, D) which included moth abundance in their calculation. We conclude that species richness within, and among, trophic levels is adversely affected by these two invasive wetland plant species.     

塔里木荒漠河岸林异质生境物种多样性比较与其测度指标筛选及评价

选择合适的物种多样性测度指标与多样性指数是进行群落多样性研究的基础工作。依据塔里木河上游荒漠河岸林样地调查资料,分别采用重要值、盖度和多度为测度指标比较了反映群落物种丰富度、多样性、均匀度和优势度12种多样性指数与异质生境群落多样性特征,并对多样性指数进行了相关分析与评价。结果表明,荒漠河岸林异质生境群落物种组成种类差异明显,轮南镇胡杨群落物种丰富度与多样性指数最高,水工三连灰胡杨群落多样性最低,土壤水盐的空间异质性是引起荒漠植被空间分布与群落多样性差异的主导因子。表征荒漠群落多样性以重要值和盖度为测度指标优于多度指标,其中以重要值为测度指标来反映群落多样性更为合理。相关与主成分分析表明,均匀度与多样性指数间的相关性高于丰富度与多样性指数,且多样性指数受均匀度、优势度指数受丰富度影响较大,反映出荒漠河岸林群落多样性主要决定于物种分布的均匀程度。12种多样性指数中Margalef丰富度指数（Ma）、Shannon-Weiner多样性指数（H）与Simpson多样性指数（D）能客观真实地反映异质生境荒漠植物群落多样性。同时,针对高度生境异质性的荒漠植物群落,还应综合考虑群落物种组成与生境特征,选择合适的多样性指数组合可更客观地反映荒漠河岸林群落多样性变化。     

Impacts of the invasive Argentine ant on native ants and other invertebrates in coastal scrub in south‐eastern Australia

Invasive ants threaten native biodiversity and ecosystem function worldwide. Although their principal direct impact is usually the displacement of native ants, they may also affect other invertebrates. The Argentine ant, Linepithema humile (Dolichoderinae), one of the most widespread invasive ant species, has invaded native habitat where it abuts peri‐urban development in coastal Victoria in south‐eastern Australia. Here we infer impacts of the Argentine ant on native ants and other litter and ground‐dwelling invertebrates by comparing their abundance and taxonomic composition in coastal scrub forest either invaded or uninvaded by the Argentine ant. Species composition of native ants at bait stations and extracted from litter differed significantly between Argentine ant‐invaded and uninvaded sites and this was consistent across years. Argentine ants had a strong effect on epigeic ants, which were either displaced or reduced in abundance. The native ant Rhytidoponera victoriae (Ponerinae), numerically dominant at uninvaded sites, was completely absent from sites invaded by the Argentine ant. However, small hypogeic ants, including Solenopsis sp. (Myrmicinae) and Heteroponera imbellis (Heteroponerinae), were little affected. Linepithema humile had no detectable effect upon the abundance and richness of other litter invertebrates. However, invertebrate group composition differed significantly between invaded and uninvaded sites, owing to the varied response of several influential groups (e.g. Collembola and Acarina). Floristics, habitat structure and measured environmental factors did not differ significantly between sites either invaded or uninvaded by Argentine ants, supporting the contention that differences in native ant abundance and species composition are related to invasion. Changes in the native ant community wrought by Argentine ant invasion have important implications for invertebrate communities in southern Australia and may affect key processes, including seed dispersal.     

Multi‐trophic impacts of an invasive aquatic plant

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Belowground community responses to fire: meta‐analysis reveals contrasting responses of soil microorganisms and mesofauna

Global fire regimes are shifting due to climate and land use changes. Understanding the responses of belowground communities to fire is key to predicting changes in the ecosystem processes they regulate. We conducted a comprehensive meta‐analysis of 1634 observations from 131 empirical studies to investigate the effect of fire on soil microorganisms and mesofauna. Fire had a strong negative effect on soil biota biomass, abundance, richness, evenness, and diversity. Fire reduced microorganism biomass and abundance by up to 96%. Bacteria were more resistant to fire than fungi. Fire reduced nematode abundance by 88% but had no significant effect on soil arthropods. Fire reduced richness, evenness and diversity of soil microorganisms and mesofauna by up to 99%. We found little evidence of temporal trends towards recovery within 10 years post‐disturbance suggesting little resilience of the soil community to fire. Interactions between biome, fire type, and depth explained few of these negative trends. Future research at the intersection of fire ecology and soil biology should aim to integrate soil community structure with the ecosystem processes they mediate under changing global fire regimes.     

Avifauna associated with ephemeral ponds on the Cumberland Plateau, Tennessee

ABSTRACT.   Although ephemeral ponds act as small hotspots of plant, invertebrate, and salamander diversity, the importance of such ponds for birds has been little studied. We hypothesized that ephemeral ponds on the Cumberland Plateau in Tennessee would support a greater abundance, richness, and diversity of birds than the surrounding hardwood forests. In 2004, we recorded all birds seen or heard in 10 min within 50-m radius circles at 25 ephemeral ponds. We repeated the counts at control sites located 150 m from each pond in the surrounding forest. To quantify potential food availability, we captured aerial invertebrates using sweep nets at four points around a subsample of eight ephemeral ponds and at an equal number of control sites. We found significantly greater bird abundance, richness, and species diversity at ephemeral ponds than at control sites, and that pond area was not associated with either bird abundance or richness. Bird community composition at pond and control sites was similar. Aerial invertebrates were significantly more abundant at ephemeral ponds than at adjacent forest sites, providing one possible explanation for greater bird abundance at ephemeral ponds.     

Contrasting effects of insect and molluscan herbivores on plant diversity in a long-term field experiment

The importance of invertebrate herbivores in regulating plant communities remains unclear, due to the absence of long-term exclusion experiments. An experiment in an English grassland involving long-term exclusions of insect and mollusc herbivores, along with rabbit fencing, showed strong, but opposing, effects of the invertebrate herbivores. Plant species richness declined and biomass increased following insect exclusion, due to increased dominance by a grass species, whereas mollusc exclusion led to increased herbs abundance. The two herbivores had a compensatory interaction: molluscs had no effects in the absence of insects and large insect effects depended on the absence of molluscs. The effects of invertebrate exclusion became apparent only after 8 years, and would have been seriously underestimated in shorter studies. Our results suggest that theorists and conservation managers need to shift from their historic focus on vertebrate herbivory, to a recognition that invertebrates can be equally important drivers of plant community structure.     

Effects of repeated burning on Mediterranean communities of the northeastern Iberian Peninsula

Question: In relation to a single fire, do repeated wildfires in Mediterranean type ecosystems (1) reduce plant species richness or diversity; (2) modify patterns of abundance or dominance of plant species or (3) alter plant composition? Location: Pinus halepensis dominated communities of Catalonia, northeastern Iberian Peninsula, western Mediterranean Basin. Methods: Regional, paired design with 14 study sites, each consisting of a once burnt area (1994) and a twice burnt area (1975–1993 and 1994). Ten years after the last fire, we recorded all vascular plant species present in nested plots and quantified their relative abundances on transects. We compared species richness, diversity, dominance and relative abundance and species‐area correlations between paired once and twice burnt areas and assessed their floristic composition similarity. Results: No statistically significant differences were found in species richness or diversity. Slopes of species‐area correlations were higher in once burnt areas. In twice burnt areas, dominance by one or two species was higher. P. halepensis showed lower relative abundance and nanophanerophytes showed higher relative abundance. No differences were found for resprouter, seeder or resprouter‐seeder species. Floristic composition similarity between paired areas tended to be higher in less productive sites. Conclusions: Fire recurrence had contrasting effects on species richness at different spatial scales. Repeated burning reduced the relative abundance of the dominant tree species, which resulted in a higher relative abundance of shrubs. It also promoted the dominance of herbs, particularly Brachypodium retusum. However, it did not change the relative abundance of regenerative groups. Paired areas were more similar as they were more Mediterranean in terms of climatic conditions.     

Ant communities and Solidago plant invasion: Environmental properties and food sources

The invasion of Solidago is one of the main threats to the biodiversity of natural meadows, leading to changes in animal and plant communities, as well as soil features. We compared effects of soil microclimatic conditions (temperature and moisture) and the availability of potential protein sources (dry mass of epigean invertebrates) on ants between meadows invaded by Solidago altissima and S. canadensis and those uninvaded. Our results showed that the ant communities were different between the uninvaded and invaded meadows, with reduction of ant abundance and species richness in the latter. Myrmica spp. were abundant in the uninvaded meadows, whereas Lasius niger was the dominant species in the invaded ones. We found that the lower moisture negatively influenced the abundance of Myrmica species in the Solidago‐invaded meadows. Moreover, the epigean invertebrate dry mass, as an estimation of the availability of protein sources, varied between the two types of meadows, with a higher abundance in the uninvaded ones. The abundance of Myrmica ants with narrower ecological requirements showed a positive correlation with the invertebrate biomass in the invaded meadows. In contrast, the abundance of L. niger with broad ecological requirements was negatively correlated with the invertebrate biomass in the invaded meadows, possibly as a strategy to reduce interspecific competition. Our study showed that the invasion of Solidago plants caused changes in the abundance and species composition of ant communities through modification in microhabitat conditions, that is, decreasing soil moisture, reducing biomass and changing distribution of prey invertebrates.     

Restore it,and they will come: trap-nesting bee and wasp communities (Hymenoptera: Aculeata) are recovered by restoration of riparian forests

Riparian forests have been greatly affected by anthropogenic actions with formerly continuous riparian forests being slowly converted into small and isolated patches. Riparian forests are extremely important habitats for many groups of insects, including bees and wasps, because they are sources of shelter and food for them and their offspring. There is a growing body of evidence of success in the restoration of riparian forest plant communities; however, little research has been done on the associated invertebrate communities. We test whether restoring plant communities is sufficient for restoring the taxonomic composition of trap-nesting bees and wasps and which functional traits are favored in different sites. We predict that species richness, abundance, and community composition of trap-nesting bees and wasps of riparian sites undergoing restoration will converge on the “target” of a reference site with increasing time, since restoration increases habitat complexity. We also predict that the width of restored patches will also influence the species richness, abundance and community composition of trap-nesting bees and wasps. Bee richness and abundance, and wasp richness, were strongly related to fragment width, but not to age since restoration. Our results indicate that although restored sites are relatively small and scattered in a fragmented landscape, they provide suitable habitat for re-colonization by community assemblages of trap-nesting bees and wasps and the traits selected captured the responses to the habitat restoration. Hence, restored riparian areas can be considered important habitats for invertebrates, thus contributing to an increase in local biodiversity and, possibly, the restoration of some of the ecosystem services they originally provided.     

Invasive ants as back-seat drivers of native ant diversity decline in New Caledonia

Biological invasions are typically associated with disturbance, which often makes their impact on biodiversity unclear—biodiversity decline might be driven by disturbance, with the invader just being a ‘passenger’. Alternatively, an invader may act as a ‘back-seat driver’, being facilitated by disturbance that has already caused some biodiversity decline, but then causing further decline. Here we examine the interactive effects of anthropogenic fire and invasive ant species (Anoplolepis gracilipes or Wasmannia auropunctata) on native ant diversity in New Caledonia, a globally recognized biodiversity hotspot. We first examined native ant diversity at nine paired burnt and unburnt sites, with four pairs invaded by Anoplolepis, 5 years after an extensive fire. In the absence of invasion, native epigaeic ants were resilient to fire, but native ant richness and the abundance of Forest Opportunists were markedly lower in invaded burnt sites. Second, we examined native ant diversity along successional gradients from human-derived savanna to natural rainforest in the long-term absence of fire, where there was a disconnection between disturbance-mediated variation in microhabitat and the abundance of the disturbance specialist Wasmannia. All native ant diversity responses (total abundance, richness, species composition, functional group richness and the abundance of Forest Opportunists) declined independently of microhabitat variables but in direct association with high Wasmannia abundance. Our results indicate that invasive ants are acting as back-seat drivers of biodiversity decline in New Caledonia, with invasion facilitated by disturbance but then causing further biodiversity decline.     

The effect of fire history in shaping diversity patterns of flower-visiting insects in post-fire Mediterranean pine forests

Fire affects diversity and structure of flower-visitor communities. We explored the effect of fire history on the diversity patterns and structure of the flower-visitor guilds (bees, beetles, flies, sawflies, and wasps), across a post-fire regeneration sequence of pine forests in Rhodes Island, Greece. Fire history was defined by fire frequency and post-fire age of sites. We did not find significant differences in species richness and abundance per guild between fire-history regimes except for the abundance of flies, sawflies and the entire flower-visitor community. Fire strongly affected the community structure of bees, beetles, and sawflies. Some of the most abundant and common species responded significantly to fire in terms of abundance; yet, we observed no significant variation in the abundance of the common species of bees, the most prominent pollinator group, implying that provision of pollination services may not be considerably affected by fire. Long-unburnt sites displayed higher heterogeneity in species composition compared to recently-burnt sites (either burnt once or twice). This pattern deviated significantly from null expectations when analyzing the abundance-based metric of β-diversity and was obscure in the case of the presence/absence-based metric, indicating that fire affected mainly the spatial distribution of individuals, i.e. the main change is not due to species turnover but to changes in relative abundance. Furthermore, the species composition in recently-burnt sites (burnt once in 2008) were more similar than in twice-burnt sites (including areas burnt once between 1984 and 1992, and in 2008), indicating that fire frequency affected post-fire heterogeneity of species composition.     

红火蚁对新入侵龙眼园和荒草地蚂蚁类群多样性的影响

于2007年7月至2008年2月期间在增城龙眼园及周边的荒草地人工移殖1蚁巢及10蚁巢红火蚁,并采用陷阱法和诱饵诱集法调查研究红火蚁对新入侵龙眼园区和荒草地区蚂蚁类群多样性的影响。结果表明,在荫蔽、少干扰的龙眼园和杂草茂密、少干扰的未割草区,红火蚁难以成功定殖,对这两种生境蚂蚁类群的多样性几乎没有影响;在红火蚁成功定殖的1蚁巢割草区和10蚁巢割草区,红火蚁以这两种密度入侵对蚂蚁类群多样性的影响程度不同。在1蚁巢割草区,红火蚁入侵后5个月期间,由于其数量占蚂蚁个体总数的比例很少,对蚂蚁类群多样性的影响很小;在红火蚁成功定殖5个月后,第6—7个月其工蚁所占比例增加,蚂蚁类群个体数和优势度下降,多样性和均匀度增加;第8—9个月其工蚁所占比例继续增加,而蚂蚁个体数、多样性和均匀度下降,优势度增加。在10蚁巢割草区,红火蚁入侵后,蚂蚁类群个体数、多样性和均匀度下降,优势度增加。红火蚁入侵对1蚁巢割草区和10蚁巢割草区蚂蚁物种数的影响较小。     

Pyrodiversity begets plant–pollinator community diversity

Fire has a major impact on the structure and function of many ecosystems globally. Pyrodiversity, the diversity of fires within a region (where diversity is based on fire characteristics such as extent, severity, and frequency), has been hypothesized to promote biodiversity, but changing climate and land management practices have eroded pyrodiversity. To assess whether changes in pyrodiversity will have impacts on ecological communities, we must first understand the mechanisms that might enable pyrodiversity to sustain biodiversity, and how such changes might interact with other disturbances such as drought. Focusing on plant–pollinator communities in mixed‐conifer forest with frequent fire in Yosemite National Park, California, we examine how pyrodiversity, combined with drought intensity, influences those communities. We find that pyrodiversity is positively related to the richness of the pollinators, flowering plants, and plant–pollinator interactions. On average, a 5% increase in pyrodiversity led to the gain of approximately one pollinator and one flowering plant species and nearly two interactions. We also find that a diversity of fire characteristics contributes to the spatial heterogeneity (β‐diversity) of plant and pollinator communities. Lastly, we find evidence that fire diversity buffers pollinator communities against the effects of drought‐induced floral resource scarcity. Fire diversity is thus important for the maintenance of flowering plant and pollinator diversity and predicted shifts in fire regimes to include less pyrodiversity compounded with increasing drought occurrence will negatively influence the richness of these communities in this and other forested ecosystems. In addition, lower heterogeneity of fire severity may act to reduce spatial turnover of plant–pollinator communities. The heterogeneity of community composition is a primary determinant of the total species diversity present in a landscape, and thus, lower pyrodiversity may negatively affect the richness of plant–pollinator communities across large spatial scales.