Fractal analysis of plant spatial patterns: a monitoring tool for vegetation transition shifts

Abstract

Spatial heterogeneity, like species diversity, is an important ecosystem property. We examine the effects of land use on the diversity and spatial distribution of plants in five semi-arid communities of eastern Spain using non-linear methods to assess the spatial-temporal dynamics of plant populations. Specifically, we are interested in detecting long-term structural changes or drift in an ecosystem before it is too late to prevent irreversible degradation. Fractal analysis is used to characterize the complexity of plant spatial patterns and Information Theory indices are used to measure change in information flow with land use changes and soil substrate. We found that grazing favored diversity and heterogeneity of species distribution on the impoverished gypsum and saline substrate community, as opposed to the detrimental effect of grazing in the Alpha steppe community. Indeed, old-field succession after 30 years of abandonment showed a recovery of species diversity but not the spatial structure of the vegetation. Further, Information Fractal Dimension, representing the unpredictability of plant spatial patterns in the landscape, increased as we moved from a highly diverse to a less diverse community, revealing the change to a more scattered and homogeneous spatial plant distribution. The Information Fractal Dimension is a good estimator of ecosystem disturbance, independent of scale, and thus can be used to monitor ecosystem dynamics.

Remote Sensing-Based Fractal Analysis and Scale Dependence Associated with Forest Fragmentation in an Amazon Tri‑National Frontier

“…Fractal analysis has been used to study complex structures for years [38,39], and there have been many analyses using fractals to understand landscape problems [40], such as animal movement, urban development, and forest management [41][42][43][44]. Fractal structures have been observed in the patterns of surface growth [45], like forest fragmentation, hence we will apply fractal analysis in this research to study the deforestation patterns around a tri-national frontier in Brazil, Bolivia and Peru, where extensive road development and paving has been occurring.…”

Pits Conserve Species Diversity in an Overgrazed Grassland

“…In the present study, pit depth influences fern diversity more than pit area. Spatial heterogeneity, including microtopography and its related environmental factors such as light and soil moisture, is one of the determinants on plant community structures [1,25]. Pit conserved fern species diversity on Nakajima Island, by the avoidance from deer feeding.…”

“…Furthermore, when plants can escape from grazing by using microtopography, the characteristics of microtopography, such as shape and size, influence grazing pressures [1]. We evaluate: (1) Palatability is related to plant community differentiation, in particular, unpalatable plants still remained on overgrazed areas. (2) Specific species establish in distinct microhabitats by avoiding grazing.…”

Do vegetation patch spatial patterns disrupt the spatial organization of plant species?

“…The additive partitioning of species diversity is a way to quantify the components of diversity among scales and measure the contribution of local communities to regional diversity (Lande, 1996;Wagner et al, 2000;Crist et al, 2003;Gering et al, 2003;Freestone and Inouye, 2006). The partitioning of plant species diversity across landscapes and regions has been investigated in agricultural landscapes (Wagner, 2003;Gabriel et al, 2006) and serpentine outcrops (Davies et al, 2005;Freestone and Inouye, 2006), but limited attention has been paid to the role of self-organizing capacity as a mechanism underlying the spatial structure of communities (Alados et al, 2005;Green and Sadedin, 2005;Seabloom et al, 2005;Barbier et al, 2006). Spatial self-organization is the ability of a non-equilibrium system to develop structure and pattern in the absence of control by external agents (Nicolis, 1989).…”

“…As ecosystems develop, long-range spatial autocorrelations arise, which lead the systems toward an increase in the heterogeneity of species distributions (Loehle et al, 1996). In contrast, an increase in disturbance often leads to unpredictability (randomness) in species distributions (Alados et al, 2003(Alados et al, , 2005Seabloom et al, 2005).…”