The Carbon Balance of Tropical Islands: Lessons from Soil Respiration
Tropical islands are often referred to as “microcosms,” given their potential to represent natural laboratories and they appeal to many scientists who study them. Despite their small size compared to larger continental land masses, tropical islands have p
- PDF / 907,634 Bytes
- 16 Pages / 439.37 x 666.142 pts Page_size
- 22 Downloads / 226 Views
duction The study of tropical islands has long shaped our understanding of the earth system as a whole by facilitating small-scale observations of a range of mechanisms and processes central to multiple disciplines, including biogeography, geoscience, population dynamics, and human-environment science. The isolation of islands promotes endemism and highlights the role of changes in biophysical resources in mediating the structure and function of natural systems (Adler, 1992; Briggs, 1966), allowing scientists to study a wide range of geological and biological phenomena over relatively small spatial scales. However, despite their smaller size, tropical islands have proven difficulty to characterize, particularly in the face of disturbance and rapidly changing land use and land cover (LULC). Tropical islands are highly heterogeneous, complex, and often exhibit confounding variables due to juxtaposed processes, mechanisms, and environmental threats (Lal, Harasawa, & Takahashi, 2002; Meehl, 1996). One aspect in which tropical islands remain difficult to characterize is in the role they play in the global carbon cycle and the magnitude and direction of carbon exchanged between the land and the atmosphere. Because land cover of islands is highly variable and rapidly changing, carbon-related processes remain difficult to quantify or even measure at the scale of entire islands. Furthermore, many tropical S. G. McQueen Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA D. A. Riveros-Iregui (*) Department of Geography, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA e-mail: [email protected] J. Hu School of Natural Resources and the Environment, University of Arizona, Tucson, AZ, USA © Springer Nature Switzerland AG 2020 S. J. Walsh et al. (eds.), Land Cover and Land Use Change on Islands, Social and Ecological Interactions in the Galapagos Islands, https://doi.org/10.1007/978-3-030-43973-6_12
261
262
S. G. McQueen et al.
islands are composed of basaltic and ultramafic rocks, which despite having a small surface area, have a disproportionately greater capacity to sequester atmospheric CO2 (McGrail et al., 2006). Thus, the extent to which tropical islands sequester or emit atmospheric carbon remains highly uncertain. Large vegetation that is characteristic of the highest, wettest, and often the most productive areas in tropical islands is often removed and replaced by crops that provide food and fodder. While farming in tropical islands remains a small-scale activity, farming leads to extremely fragmented landscapes with multiple and varied land uses, posing consequences on soil carbon sequestration potential. Tropical islands are also known for being affected by the proliferation of invasive species (Kueffer et al., 2010). Invasive plants alter ecosystems through the modification of physical, chemical and biological properties, including soil structure, soil water holding capacity, and soil chemical composition. Pacific Islands, for example, have experienced the highes
Data Loading...
