Multi-scale Habitat Preference Research Based On Hostplant Of The Butterfly Teinopalpus Aureus

Teinopalpus aureus is a large butterfly endemic to tropical and subtropical Asia,which is distributed in a few mountains with steep terrain and covered with primeval forest.As a typical mountain forest butterfly,it has many adaptive characteristics to broad-leaved forest habitats and has strict requirements on habitat conditions.It is regarded as a habitat specialist species.Its confirmed host plants are all from Magnoliaceae trees,indicating it is an oligophagous species.However,these habits have also led to many difficulties in field investigation.And therefore,this butterfly has been classified as “Data Deficient” by IUCN for many years,and today what limits its occurrence is still unclear.In this study,with the cooperation of local works of Nature Reserve in Jiulianshan,we collected the occurrence characteristics and environmental data of T.aureus on small scales(such as habitat and microhabitat scale)through line transects in Jiulianshan.We explored the habitat demands of T.aureus on small scales and the related hostplant limitations in butterfly occurrence.At the same time,based on the small-scale results,we choose the key factors affecting the occurrence of butterflies at the landscape scale,to establish a species distribution model and explore the habitat requirements and potential suitable distribution at the landscape scale.On this basis,through extensive investigation in the mountainous areas of southern China,we collected distribution information of Magnoliaceae plants and T.aureus,to explore the hostplant resources-habitat distribution and protection planning at the landscape scale..The main results are as follows:(1)On the habitat scale,the occurrence of T.aureus is limited by the altitude,habitat type and host plant resources.The host plant limitation is mainly driven by the available hostplant.Butterflies prefer to occur in primeval forests in mid-mountain areas with better host plant resources.Their habitat needs include two levels:(1)the basic needs,i.e.,forest quality requirements,including altitude(e.g.,central Mountains),forest origin(e.g.,primeval forest),forest structure(e.g.,evergreen broad-leaved forest),and tree structure(e.g.,tree height and DBH in Magnoliaceae),and(2)the advanced needs,especially the requirements for the key consumables of hostplants,including the hostplant diversity and abundance.Obviously,it is only after the basic needs are satisfied that the habitat can support the occurrence of this rare butterfly,and at this time,the hostplant limitation is then critically driven by the hostplant availability,rather than simply by the hostplant abundance alone.At the same time,host plant diversity can better reflect the quality level of ’Resource-based habitats’ than simple host plant abundance.(2)On the microhabitat scale,the oviposition site selection of T.aureus was affected by topography,vegetation structure,and host plant resources,and the preference of oviposition sites between spring and summer generations was different.In terms of host plant selection,the oviposition sites of both generations prefer to be located in areas with more available hostplant.At this time,the key role of available hostplant for butterflies is to provide more suitable microhabitats for oviposition.In the geography,the summer generation needs the sunny slope of the dry and hot environment,but the spring generation needs the wet shady slope.In terms of vegetation structure,the summer generation preferred areas with small average DBH of trees,while the spring generation required mature forests with larger average DBH of trees and higher canopy coverage.The different selection tendencies of butterflies in topography and vegetation structure,may be due to the adaptive characteristics of the dry and wet season alternate climate of subtropical forests in the long-term evolution.The demand for mature forests in spring generation may be the main bottleneck restricting for butterfly population size together with the available hostplant.(3)Deforestation and other human disturbance activities strongly affect the species composition and resource distribution of Magnoliaceae plants at the habitat scale,and indirectly threaten the survival of T.aureus.With the increase in cutting intensity,the abundance,diversity,average tree height,and DBH of Magnoliaceae plant resources showed a significant downward trend.Among the host plants indicators,the available hostplant is the only key factor affecting the occurrence of butterflies.However,due to the slow growth rate of Magnoliaceae plants,although after years of protection,most plants have not yet returned to the availability level(tree height,exposure index,etc.)of T.aureus.Therefore,the large-scale deforestation in the history of China may be an important driving factor for why T.aureus only occurs in a few high-altitude mountains.(4)At the landscape scale,the main environmental factors limiting the potential distribution of T.aureus were average altitude,forest landscape integrity index,and host plant resources.Most of the suitable areas for the butterfly are located in highaltitude areas(83.7%),and only a few are located in low-altitude areas(16.3%).The Gap analysis showed that most of the suitable areas of T.aureus were not strictly protected,and there were many protection vacancies(90%).In the medium and high suitable areas,butterfly are still strongly limited by host plant resources and prefer to occur in areas with higher abundance and diversity of Magnoliaceae plants.In this context,in future protection planning,it is urgent to further understand the characteristics of its demand for host plant resources.And we need to combine the field investigation of Magnoliaceae plants to defin priority protection areas.