Canopy arthropod diversity associated with Quercus laurina : importance of an oak species diversity gradient on abundance, species richness and guild composition

Central-west and south of Mexico are particularly rich in oak species, coexisting from two to six species and generating gradients of oak diversity that could potentially affect community structure of canopy arthropods. We evaluated changes in canopy arthropod diversity of the Quercus laurina along a gradient of oak diversity in the central-west portion of the Trans-Mexican Volcanic Belt. Five study sites that represent an oak diversity gradient and, where Q. laurina is also widespread were selected. At each site, five mature trees of Q. laurina were randomly selected to collect canopy arthropods using fogging techniques. We assessed the effects of local climate variables on the oak community and the canopy arthropod diversity. We collected 7479 arthropods representing 1154 morphospecies grouped into 15 different orders. Differences in arthropod diversity, abundance and guild composition between oak communities were detected. The general pattern showed a highest richness and abundance of arthropods in Tequila volcano, which represented the site with the greatest diversity of oaks. A significant positive relationship between arthropod abundance and oak species diversity was found. Arthropod guild composition differed along the gradient of oak diversity. Local environmental variables were related with oak community, but did not explained canopy arthropod diversity. At the local scale, plant species richness is the main factor that determines the canopy arthropod abundance and richness of Q. laurina , affecting the structure and composition of arthropod guilds. We highlight the importance of conserving oak species because they represent key elements of temperate forest that harbor high arthropod diversity. Implications for insect conservation Our findings confirm that at the local scale, plant species richness is the main factor that determines the arthropod diversity associated with the canopy of Quercus laurina , affecting trophic levels and the composition of arthropod guilds. Therefore, the oak species diversity in temperate forests is a key factor to harbor and preserving the diversity of canopy arthropods in temperate ecosystems.