Using high‐resolution multi‐spectral imagery to estimate habitat complexity in open‐canopy forests: can we predict ant community patterns?

Abstract

2005. Using high-resolution multi-spectral imagery to estimate habitat complexity in open-canopy forests: can we predict ant community patterns? Á/ Ecography 28: 495 Á/504.The structure and composition of arthropod assemblages are strongly associated with habitat complexity. Accurate, time efficient estimates of habitat complexity may provide insights for biodiversity management in natural systems. We obtained high-resolution (0.7 m pixel) multi-spectral aerial imagery of National Parks 20 km north and 20 km south of Sydney, Australia. We explored both the Normalised Difference Vegetation Index (NDVI) and the standard deviation of reflectance in the near-infrared spectrum (stdevR NIR ) as indicators of low and high habitat complexity in sandstone forests north of Sydney. We then tested described predictions of ant community patterns (based on a previous study) using sites selected from high-resolution multi-spectral imagery in sandstone forests south of Sydney. Ground-scored habitat complexity was positively correlated with NDVIs and, to a lesser extent, stdevR NIR values in sandstone forests north of Sydney. As predicted, ant species richness was negatively correlated with NDVIs in forests to the south of Sydney. Also, ant species composition was different in areas with contrasting NDVIs. The ant species driving composition differences responded to habitat complexity in a similar way in forests to the north, and south, of Sydney. The strong association we detected between NDVIs and habitat complexity, most likely reflects the relatively exposed nature of the vegetative layers in the forests we sampled. Remote sensing, integrated with quantitative research testing predictive faunal responses to vegetation structure and biomass at landscape scales, may provide efficient means of estimating biodiversity for management in particular habitats.

Annual and Seasonal Changes in the Structure of Litter-Dwelling Ant Assemblages (Hymenoptera: Formicidae) in Atlantic Semideciduous Forests

“…On the other hand, ecological variables such as increased litter production in association with the high heterogeneity of the vegetation may also happen in association to close and tall forests [49], which results in high spatial complexity, allowing diversification of conditions, thus sheltering a large number of species of ants and other invertebrates in the litter and soil [31,45,48,[50][51][52]. Other studies in tropical forests have corroborated that differences of litter ants species diversity and distribution respond to habitats with low and high structural heterogeneity [53][54][55].…”

A comparison of the leaf-litter ant fauna in a secondary atlantic forest with an adjacent pine plantation in southeastern Brazil

“…Sites with greater resources heterogeneity could shelter more species (Lassau & Hochuli 2004, Lassau et al 2005 because of a higher number of partitionable niche dimensions (the "microhabitat specialization hypothesis"; Brose 2003, Cramer & Willig 2005. These resources are less accessible in monocultures, especially in areas covered by Pinus, by virtue of the allelopathic effects caused by the pine needles that form exclusively the understorey, composed of fatty acids, terpenes and a variety of phenols, preventing the regeneration of native plants.…”

High resolution satellite imagery for tropical biodiversity studies: the devil is in the detail

“…For instance, studies in Australian woodlands (see e.g., Lassau et al 2005) also indicate that hyperspatial multispectral imagery from a Compact Airborne Spectrographic Imager (CASI-2) enables the Wne scale evaluation of habitat heterogeneity, and facilitates predictions of ant biodiversity. These investigators conclude that analysis at this level of detail would not have been possible using medium resolution imagery such as Landsat.…”