Modelling the nesting-habitat of threatened vulture species in the caucasus:An ecosystem approach to formalising environmental factors in species distribution models

Abiotic factors play an important role in species localisation,but biotic and anthropogenic predictors must also be considered in distribution modelling for models to be biologically meaningful.In this study,we formalised the biotic predictors of nesting sites for four threatened Caucasian vultures by including species distribution models(wild ungulates,nesting tree species)as biotic layers in the vulture Maxent models.Maxent was applied in the R dismo package and the best set of the model parameters were defined in the R ENMeval package.Performance metrics were continuous Boyce index,Akaike's information criterion,the area under receiver operating curve and true skill statistics.We also calculated and evaluated the null models.Kernel density estimation method was applied to assess the overlap of vulture ecological niches in the environmental space.The accessibility of anthropogenic food resources was estimated using the Path Distance measure that considers elevation gradient.The availability of pine forests(Scots Pine)and wild ungulates(Alpine Chamois and Caucasian Goat)contributed the most(29.6%and 34.3%)to Cinereous Vulture(Aegypius monachus)nesting site model.Wild ungulate distribution also contributed significantly(about 46%)to the Bearded Vulture(Gypaetus barbatus)model.This scavenger nests in the highlands of the Caucasus at a minimum distance of 5–10 km from anthropogenic facilities.In contrast,livestock as a food source was most important in colony distribution of Griffon Vulture(Gyps fulvus).The contribution of distances to settlements and agricultural facilities to the model was 45%.The optimal distance from Egyptian Vulture(Neophron percnopterus)nesting sites to settlements was only 3–10 km,to livestock facilities no more than 15 km with the factor contribution of about 57%.Excluding the wild ungulate availability,the ecological niches of studied vultures overlapped significantly.Despite similar foraging and nesting requirements,Caucasian vultures are not pronounced nesting and trophic competitors due to the abundance of nesting sites,anthropogenic food sources and successful niche sharing.

New macroalgal fossils of the Kaili Biota in Guizhou Province, China

The Kaili Biota of Jianhe County, Guizhou Province is found in a Burgess Shale type of deposits, and as such it provides a key fossil record for studying biotic differentiation following the Cambrian explosion. Macroalgae represent several important groups of primary producers and yet have not been well studied. Here, we report two new forms of macroalgae from the Kaili Biota, including a new genus and species and an indeterminate genus and species. The new genus and species, Parallelphyton tipica, is a heterotrichous alga with thalli composed of a prostrate cardinal axis, and parallel bundles of erect trichomes on the axis. The bifurcation of the trichomes is somewhat similar to the living heterotrichous Fritschiella （Chlorophyta）, representing ＂architectonic differentiation＂ only known in higher plants as an adaptation to terrestri~ conditions. The indeterminate genus and species consists of an arched, thick, cylindrical major shaft and irregularly spaced, curved lateral branches attached to the major shaft and subdivided into subbranches. The characteristics of the thick and strong major shaft and the lateral branch subdivided branches are analogous to the dichotomous branching of Psilophyton in Protopteridophyta. Thus, the differentiation of the thalli in these two algal forms represents the expression of properties of some higher metaphytes, indicating that the eco- logical differentiation of the macroalgae was well underway at the time of the Kaili Biota.