Effects of Environmental Factors and Alien Plant Invasion on Native Floral Diversity in Mt. Manunggal, Cebu Island, Philippines

Jake Joshua Chi Garces,M J L Flores

doi:10.12944/cwe.13.3.12

Jake Joshua Chi Garces, M J L Flores

Open Access

https://doi.org/10.12944/cwe.13.3.12

Copy DOI

Abstract

The status of native floral diversity in Mt. Manunggal, Cebu Island, the Philippines in relation to environmental factors and alien plant invasion has not been recorded and published. To assess factors influencing native plant communities in Mt. Manunggal, a vegetation survey of native and alien plants, as well as selected environmental variables at two sites (Site 1- invaded plot; Site 2- adjacent uninvaded plot) were measured, and anthropogenic disturbances observed using a t-test, regression analysis, and Pearson correlation. For each site, selected environmental parameters, as well as native and alien plant abundance and diversity, were determined last October-November, 2016. There was also a characterization of sites with respect to anthropogenic disturbances. Altitude (t= -14.11, p=0.000), soil temperature (t=2.68, p=0.014), and light intensity (t = -2.61; p=0.016) significantly differed between study sites due to the complex topography and geology of Mt. Manunggal, the variation in floral cover, and degree of anthropogenic activities. Among all environmental factors at both sites, altitude was highly positively correlated to alien plant abundance (r=0.709;p=0.000) at Site 1 while native plant abundance at Site 2 was negatively correlated with soil pH (r=-0.579;p=0.003).There was an apparent domination of alien plants in terms of species richness and abundance at both sites and this could have significantly affected native plant abundance. The strong correlation of environmental parameters to alien plant invasion could favor the continued dominance of alien plant species, resulting in a further decrease of native species.

Highlights

Plant diversity patterns and composition can be influenced by several abiotic and biotic factors at different spatial scales
As ecosystems are unceasingly degraded by anthropogenic activities, biological invasion studies became a mainstream discourse in improving our knowledge of propagule pressure, assembly time, and invasion patterns of invasive alien species (IAS), including the substantial progress in understanding the mechanisms of invasion processes.[6,7]
Remarks: *** Correlation is significant at the 0.001 level (2-tailed) **Correlation is significant at 0.01 level (2-tailed) * Correlation is significant at the 0.05 level (2-tailed) --Correlation is not significant increase in elevation, soil temperature significantly decreased (r= -0.441, p=0.031), while soil pH and light intensity increased (r=0.859, p=0.038; r=0.480, p=0.017, respectively)

Summary

Introduction

Plant diversity patterns and composition can be influenced by several abiotic and biotic factors at different spatial scales. Plant diversity and composition are influenced by geophysical factors (i.e., soil, topography), land use, and biotic interactions. Plant communities are influenced by climatic factors and biogeographical processes such as the action of pollinators and dispersal patterns.[1] Islands nations like the Philippines tend to have high endemicity than countries in continental landmasses. These islands are more vulnerable to biological invasions.[2,3,4] Biological invasions affect biodiversity worldwide.[5,6] As ecosystems are unceasingly degraded by anthropogenic activities, biological invasion studies became a mainstream discourse in improving our knowledge of propagule pressure, assembly time, and invasion patterns of invasive alien species (IAS), including the substantial progress in understanding the mechanisms of invasion processes.[6,7]

Methods

Results

Conclusion