Orchids are potentially useful as ecological indicators because of their sensitivity to habitat fragmentation and anthropogenic disturbance. While many studies explore the effect of single factors on orchid diversity, few investigate how the extent, configuration, and condition of surrounding habitat affect whole orchid communities. Here, we unravel the effect of biological invasions, anthropogenic disturbance (i.e., grazing pressure, ecological condition), and habitat fragmentation on an Australian orchid community. We sampled 39 plots across nine sites in the Mount Lofty Ranges, Australia. We recorded the number of orchid species and number of individuals per species in mid‐winter, early‐spring, and late‐spring to account for the effect of season on species visibility, with 115 surveys in total. We ranked grazing intensity and ecological condition, and estimated cover of exotic species. We analyzed the response of richness and diversity through generalized linear mixed models, and differences in species composition through non‐metric multidimensional scaling. Habitat configuration in the surrounding landscape had different effects at increasing radii, explaining 29%–87% of variance. Patch‐level orchid diversity was positively correlated with habitat edges in the immediate area, and with habitat cohesion at medium scales, whereas diversity was negatively correlated with increasing mean patch habitat area across larger surrounding areas. Orchids co‐existed with exotic species but were negatively affected once exotic cover exceeded 20%. Species composition was correlated with exotic cover. Our findings reveal a complex relationship between orchid communities and their surrounding environments suggesting orchids benefit from a somewhat disturbed environment at patch and landscape scales. These idiosyncratic responses suggest orchid diversity may be unreliable as early‐warning indicators of habitat disturbance.

To maintain recruitment in orchid populations in an ecosystem setting, we must understand how surrounding floral resources affect fruiting success. We studied fruiting success in two endemic Australian species, Diruis pardina and Glossodia major, in relation to surrounding floral resources. Diuris pardina has a visually deceptive pollination strategy via mimicry of pea flowers, attracting pollinators associated with co-flowering plants of Pultenaea. Glossodia major displays dummy anthers and has a more generalist pollination strategy. We expected fruit set of both species to positively correlate to conspecific and heterospecific floral density because orchid pollination should be enhanced by the attraction of higher densities of bees. We expected fruiting success of D. pardina to positively correlate with abundance of Pultenaea flowers. Surveying 18 plots in South Australia, we counted species, individuals and flowers of conspecifics and heterospecifics and returned to count flowers that set fruit. We conducted Pearson correlations between fruiting success and density of conspecific flowers, richness, abundance and Shannon index of surrounding floral resources and floral abundance of individual species. Fruiting success was correlated with conspecific floral density for Diuris pardina but not G. major. No relationship was found between fruiting success and heterospecific floral resources. Fruiting success of D. pardina was not correlated with abundance of Pultenaea; instead it was positively correlated with the invasive species Lavandula stoechas.

Orchids are potentially useful as ecological indicators because of their sensitivity to habitat fragmentation and anthropogenic disturbance. While many studies explore the effect of single factors on orchid diversity, few investigate how the extent, configuration and condition of surrounding habitat affect whole orchid communities. Here, we unravel the effect of biological invasions, anthropogenic disturbance (i.e. grazing pressure, ecological condition), habitat fragmentation and climate on an Australian orchid community. We sampled 39 plots across nine sites in the Mount Lofty Ranges, Australia. We recorded the number of orchid species and number of individuals per species in mid-winter, early-spring and late-spring to account for the effect of season on species visibility, with 115 surveys in total. We ranked grazing intensity and ecological condition, and estimated cover of exotic species. We analysed the response of richness and diversity through generalised linear mixed models, and differences in species composition through non-metric multidimensional scaling. We also explored fruiting success in two species associated with floral resources in the surrounding habitat. Habitat configuration in the surrounding landscape had different effects at increasing radii. Patch-level orchid diversity was positively correlated with habitat edges in the immediate area, and with habitat cohesion at medium scales, whereas diversity was negatively correlated with increasing habitat area across larger surrounding areas. Orchids co-existed with exotic species but were negatively affected once exotic cover exceeded 20%. Species composition was correlated with both exotic cover and level of disturbance. Fruiting success was unrelated to floral resources of the surrounding vegetation, although associated with certain bee-attracting species. Our findings reveal a complex relationship between orchid communities and their surrounding environments suggesting that while orchids benefit from a somewhat disturbed landscape, they fail to thrive once exotic cover exceeds 20%. These idiosyncratic responses suggest orchid diversity may be unreliable as early-warning indicators of habitat disturbance.

To maintain recruitment in orchid populations in an ecosystem setting, we must understand how surrounding floral resources affect fruiting success. We studied fruiting success in two endemic Australian species, Diruis pardina and Glossodia major, in relation to surrounding floral resources. Diuris pardina has a visually deceptive pollination strategy via mimicry of pea flowers, attracting pollinators associated with co-flowering plants of Pultenaea. Glossodia major displays dummy anthers and has a more generalist pollination strategy. We expected fruiting success of both species to positively correlate to conspecific and heterospecific floral density because orchid pollination should be enhanced by the attraction of higher densities of native bees. We expected fruiting success of D. pardina to positively correlate with abundance of Pultenaea flowers. Surveying 18 plots in South Australia, we counted species, individuals and flowers of conspecifics and heterospecifics and returned to count flowers that set fruit. We conducted Pearson correlations between fruiting success and density of conspecific flowers, richness, abundance and Shannon index of surrounding floral resources and floral abundance of individual species. Fruiting success was correlated with conspecific floral density for Diuris pardina but not G. major. No relationship was found between fruiting success and heterospecific floral resources. Fruiting success of D. pardina was not correlated with abundance of Pultenaea; instead it was positively correlated with the invasive species Lavandula stoechas.