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Vol. 51 No. 8, 2012
Differences in Alpha and Beta Diversities of Epigeous
Arthropod Assemblages in Two Ecoregions of Northwestern Argentina
Andrea
Ximena González Reyes1, José Antonio Corronca1,2,*,
and Norma Carolina Arroyo1
1Instituto
para el Estudio de la Biodiversidad de Invertebrados, Facultad de
Ciencias Naturales, Univ. Nacional de Salta, Av. Bolivia 5150, Salta
C.P 4.400, Argentina
2Consejo Nacional de Investigaciones Científicas y
Técnicas (CONICET), Salta, Argentina
Andrea Ximena González Reyes, José Antonio
Corronca, and Norma Carolina Arroyo (2012) Ecoregions are
regional-scale biodiversity units. Several of them converge in
Salta Province, Argentina, where Puna and Monte are priority
conservation areas for different reasons. The aims of our
research were to (1) analyze the inventory obtained by determining the
alpha and beta diversities of the arthropod communities in the
ecoregions; (2) attempt to establish the most likely factors
responsible for the distribution patterns of the epigeous communities
present in the Monte and Puna take off; and (3) show the main changes
in abundance and species richness of the most diverse arthropod groups
recorded over space. Pitfall traps were used to collect epigeous
arthropods. Several soil variables were measured in the field in
addition to climatic variables. The total inventory and data by
sites were evaluated using nonparametric estimators. Observed and
estimated diversity values were used to compare epigeous arthropod
communities between ecoregions. Beta diversity was assessed by
different methods. The abundance-based Morisita index was used to
investigate the degree of association between ecoregions and sampling
sites. We used a non-metric multidimensional scaling analysis to
show the ordination of the studied sites following the similarity of
arthropod assemblages and possible relationships with environmental
variables that could explain it. Species richness differed
between ecoregions, and the true diversity showed that Puna was
1.30-times more diverse than Monte de Sierras y Bolsones. The
inventory completeness was adequate (78%), and differed between
sites. Species turnover was high with a clear ecoregional faunal
separation. The most diverse arthropods orders were spiders,
coleopterans, and hymenopterans, which exhibited differences in
abundance and species richness between ecoregions. Different
factors of soil heterogeneity and climate, which are important in arid
environments, exerted an influence on the assemblages of epigeous
arthropods obtained.
Key words: Biodiversity, Monte de Sierras y
Bolsones, Puna, Local diversity, Species turnover.
*Correspondence: Tel: 54-0387-4255437.
E-mail:jcorronca@gmail.com
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