The net impact of connectivity on disease risk can be either positive or negative, depending on the relative importance of the facilitation effect (through increasing contact rates among patches) versus the dilution effect (via increasing species richness).
Attention to the link between evenness and ecosystem function is critical because ecological interactions and human activities, such as targeted harvests, often modify evenness by skewing species abundances rather than by reducing species richness via extinction [5], [12], [13].
Similarly, plant genetic diversity may increase pollinator abundance and richness via facilitative interactions of neighboring plants and greater variation in floral forms and nectar quality leading to a higher diversity of flower visitors [4], [8] [10].
We also assembled a second dataset (a subset of the first), designed to further investigate similarity of species assemblages, and to estimate species richness via an incidence-based method.
Therefore, a higher proportion of graminoids indirectly reduced leafhopper species richness via its negative effect on plant diversity, but also had a direct positive effect due to greater availability of the preferred food source.
We compared measures of alpha diversity (species richness and Shannon H′) via Kruskal Wallace tests followed by Steel Dwass non-metric means comparisons in SAS-JMP 9.0.0 (JMP 2010).
2007) consists of sampling a population at regular intervals and estimating metrics (i.e., heterozygosity, relatedness, allelic richness, effective population size) via standardized analysis that permits meaningful characterization of change in populations over time.
Molecular methods for quantifying species richness typically exceed estimates made via morphology alone, because molecular methods both reveal cryptic species and permit inclusion of specimens that would otherwise remain unidentified [ 1, 22].
Population genetic theory posits that the first genetic signature of a population crash should be a marked reduction in the number of alleles per locus (i.e., allelic richness) as rare alleles are lost via genetic drift [5].
Allelic richness (AR) was calculated by rarefaction via the program HP-Rare as described by Kalinowski (2005).
