Monarchs in decline： a collateral landscape-level effect of modern agriculture

We review the postulated threatening processes that may have affected the de- cline in the eastern population of the monarch butterfly, Danausplexippus L. （Lepidoptera： Nymphalidae）, in North America. Although there are likely multiple contributing factors, such as climate and resource-related effects on breeding, migrating, and overwintering populations, the key landscape-level change appears to be associated with the widespread use of genetically modified herbicide resistant crops that have rapidly come to dominate the extensive core summer breeding range. We dismiss misinterpretations of the apparent lack of population change in summer adult count data as logically flawed. Glyphosate-tolerant soybean and maize have enabled the extensive use of this herbicide, generating widespread losses of milkweed （Asclepias spp.）, the only host plants for monarch larvae. Modeling studies that simulate lifetime realized fecundity at a landscape scale, direct counts of milkweeds, and extensive citizen science data across the breeding range suggest that a herbicide-induced, landscape-level reduction in milkweed has precipitated the decline in monarchs. A recovery will likely require a monumental effort for the re-establishment of milkweed resources at a commensurate landscape scale.

A framework for considering ecological interactions for common non-timber forest product species:a case study of mountain date palm(Phoenix loureiroi Kunth)leaf harvest in South India

Introduction:Many economically important non-timber forest products(NTFPs)come from widespread and common plant species.Harvest of these species often is assumed to be sustainable due to their commonness.However,because of the ecological roles of common species,harvest may affect and be affected by ecological interactions at broader scales,which are rarely considered when evaluating the sustainability of harvest.We use a case study of the mountain date palm(Phoenix loureiroi Kunth),harvested in South India to produce brooms,to present a conceptual framework illustrating how intensive harvest of a common species interacts with other anthropogenic management practices,plant-animal interactions and surrounding environmental conditions.Methods:We apply this framework to understanding the impacts of mountain date palm harvest in the southern Western Ghats regions of the Indian states of Tamil Nadu and Karnataka.We integrate data on the extent and levels of commercial harvest,local management practices,the ecological context in which harvest occurs,and research on harvest effects.We use this information to document the intensity and extent of mountain date palm harvest in the study area,identify the ecological implications of harvest,and demonstrate how a framework that considers harvest in the context of ecological communities and ecosystems is important for assessing the impacts of harvest of common NTFP species.Results:We show that mountain date palm leaves are heavily harvested from natural areas in the southern Western Ghats but that harvest levels have declined in recent years.Mountain date palm management and harvest occur within a network of ecological interactions,linking human activities to population-,community-,and ecosystem-level processes.We demonstrate that understanding the effects of return interval of anthropogenic fire,herbivory by wild animals and livestock,as well as the light environment in which harvest occurs are critical to assessing the sustainability of mountain date palm harvest.Conclusions:By considering mountain date palm leaf harvest in the context of ecological interactions at multiple scales,our findings show that sustainability cannot be assessed only from a population-level perspective.This general framework highlights the need to incorporate ecosystem-and community-level properties and processes more frequently into assessments of the sustainability of NTFP harvest—especially for widespread and common species—to ensure that their important economic and ecological roles are maintained.

Comparative sensitivity to environmental variation and human disturbance of Asian tapirs (Tapirus indicus) and other wild ungulates in Thailand

Southeast Asia’s tropical forests suffer the highest rates of deforestation and disturbance of any on Earth,with poorly understood impacts on native fauna.Asian tapirs(Tapirus indicus)are among the least studied of the large mammals in these forests.Using records from 9 camera trap surveys in 7 of the largest(>1000 km2)pro-tected area complexes,we assessed the influence of environmental variation and human-induced disturbance on tapir occurrence.Tapirs were detected at 13%of locations sampled,significantly associated with evergreen for-est(P<0.001).A multiple logistic regression model predicted tapir presence 87%of the time.According to this model,tapir occurrence was positively influenced by annual rainfall and proximity to the forest edge.Howev-er,tapirs may not avoid edges but instead prefer wetter evergreen forest,a habitat type that tended to occur fur-ther from the forest edge at higher elevations in our particular study sites(P<0.001).By comparison,4 other wild ungulate species that share habitats with tapirs showed a range of differing responses.Tapirs are expect-ed to be less sensitive to disturbance because they are not targets for hunting and trade,and are almost entire-ly active at night,so avoid peak traffic periods in parks.Tapir populations in Thailand may be more stable than in other parts of their global range because rates of forest loss have decreased>40%over the past 20 years.We recommend surveys to fill gaps in the understanding of the status in lesser-known protected areas,research to better understand the fine-scale environmental influences on behavior and habitats of tapirs,and other forest un-gulates,and continued legal status for tapirs in the highest category of protection.