Arthropod diversity in contrasting habitats of a natural preserve in Mexico City

We studied the community of arthropods inhabiting the ecological preserve El Pedregal de San Angel, in Mexico City. We estimated morphospecies richness, abundance, and diversity patterns in two contrasting habitats, open (OH) and closed (CH) habitats, along four seasons of the year. Since CH have higher primary productivity than OH, we predicted that arthropod diversity would be higher in CH than in OH. Results showed that morphospecies richness of Acari and Arachnida was similar in both types of habitats throughout the year, whereas some orders of Insecta such as Coleoptera, Diptera, Hemiptera, and Hymenoptera presented the highest richness in OH. Mites were the most abundant arthropod and were always more abundant in OH than CH. Our results suggest that primary productivity might have some effects on arthropod diversity because during fall and spring evenness was lower in OH than in CH due to an increase in the abundance of the mite Mochloribatula sp. The higher productivity of the grass Muhlenbergia robusta could enhance the abundance of this mite. We suggest that the analysis of the diversity of arthropod of El Pedregal represents a base-line to understand the effects of spatial and temporal variables on this important group of organisms. This type of analysis should be considered in the preservation of arthropods and their natural habitats.