Guild-dependent effects of forest fragmentation in canopy arthropod diversity associated to Quercus deserticola

Forest fragmentation is one of the main factors leading to biodiversity loss and negatively affecting arthropod communities. We analyzed the effects of forest fragment size and habitat type (forest edge x interior) on the canopy arthropod diversity of Quercus deserticola in the Cuitzeo Basin in Mexico. Six forest fragments where Q. deserticola occurs were selected and classified as (i) small (≤ 10 ha); (ii) medium (≥ 25 ha); and (iii) large (≥ 65 ha). In each forest fragment, ten trees were randomly selected: five at the edge and five in the interior of the fragment to sampled canopy arthropods using fogging techniques. We collected 12,739 arthropods representing 716 morphospecies grouped into 155 families and 16 orders. Differences in canopy arthropod community and species diversity were detected between fragment sizes. Canopy arthropod diversity was greater in Q. deserticola individuals from small fragments and the edges of fragments than in larger fragments and in the interior of fragments. Small fragments had highest phytophages diversity and lowest parasitoids and predator’s diversity. The opposite pattern was observed in large fragments. Our results confirm that fragment size and edge effects modify canopy arthropod diversity of Q. deserticola , disrupting interactions between guilds and trophic levels probably by bottom-up and top-down forces. We highlight the importance to conserving large fragments to maintain the unique arthropod community that is sensitive to the disruption of ecological interactions and functions in Mexican temperate ecosystems, which constitute the main center of diversification and endemism of oaks in the northern hemisphere.