In most environments, inter-related biotic and abiotic factors influence vegetation composition and distribution. Over large geographic scales, climate is considered the most important driver of vegetation patterns, but other factors dominate at local scales. Locally, topographic characteristics are important contributors to vegetation composition and distribution. Topography also interacts with hydrology and soil, among other factors, to further contribute to vegetation spatial patterns. In Belize, ecological studies since the early 20th century emphasize a strong relationship between vegetation and topography – with higher canopies existing on slopes and at high elevations, and the lowest vegetation occurring in low-lying, flat areas. Here, we test and lend additional data to these long-held hypotheses about the vegetation-topography relationship in this region through the use of newly acquired lidar data. We specifically examine the interaction between canopy height and topography within a 142 km2 study area the Rio Bravo Conservation Management Area (RBCMA) in northwestern Belize. The limestone escarpments and floodplain present here lend to dynamic topography and the effective study of vegetation-topography relationships. The topographic characteristics and canopy heights were derived from a lidar dataset for northwestern Belize and assessed using spatial statistics and regression analyses.
Results/Conclusions
Elevation, aspect, microtopography, and topographic position all influence canopy height in RBCMA, and in some instances the relationship varies based on the relative size of the canopy and the influence of the surrounding area. Generally, there is a positive relationship between canopy height and elevation, microtopography, and topographic position. These relationships indicate that high canopy heights are correlated with elevated, convex surfaces that are likely more well-drained. Canopy height has a negative relationship with both the cosine and sine of aspect, suggesting that higher canopies occur on south- and west-facing slopes. Together, the varying canopy heights in northwestern Belize can be partially explained by topographic characteristics. The results aid in understanding the drivers of vegetation distribution in this region. It also presents tools that can be utilized to better understand vegetation in this area. These intact environments impart valuable ecosystem services to local and global populations; yet, they are increasingly threatened with expanding industrialized agriculture. Thus, an understanding of vegetation distribution and dynamics can work towards better describing and preserving services provided by subtropical forests.