Revista Chilena de Historia Natural 79 (2): 195-211, 2006
RESEARCH ARTICLE
Relationship between habitat characteristics and insect assemblage structure in urban
freshwater marshes from central-south Chile
Wetlands are one of the most productive ecosystems which provide a number of
ecosystem functions, maintaining also a high biodiversity. Nevertheless, almost half of the wetlands in the world have disappeared in
the last century due to urban development process. Along the Chilean landscape a great variety of aquatic habitats exist. Due to urban
expansion those ecosystems have been exposed to strong anthropogenic pressures. In the intercomunal area Concepción-
Talcahuano- San Pedro (Biobío Region), more than 23 % (1,734 ha) of the wetland areas have been lost in the last three decades. We
evaluated the relationship between habitat characteristics (morphometric, limnology and vegetation) and the insect assemblage’s
structure in seven freshwater marshes in this intercomunal area. Our aim was to assess the influence of urbanization on the diversity
patterns of these ecosystems. Insect abundance and species diversity were positively correlated to matrix pristinness and oxygen
concentration of the water, this last feature was the best predictor for the structure of the insect assemblage. Of the 24 insect
morphospecies included in the analysis, the abundance of only seven species was significantly related to the quantified habitat
characteristics. Matrix pristinness, wetland area, vegetation heterogeneity and water oxygen concentration were positively related to
species abundance, however, conductivity and water density showed a negative effect on the abundance. The insect species diversity
decrease determined by the habitat characteristics associated to habitat loss, habitat fragmentation, habitat homogeneity, and wetland
contamination, show that insects could be used as indicators of the urban effects on the functioning of these ecosystem. However, due
to the missing biological and taxonomical information on the insect species related to freshwater marshes, only habitat characteristics
with a significant effect on a high taxonomical level could be considered to establish initial recommendations for management
plans.
Key words:
conservation, wetlands,
urbanization, habitat fragmentation, water quality, biodiversity, insects,Chile.
