David Augustine

Dr. David Augustine


Research Focus & Metrics

Academic Career Length

32Years (1995-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

View All Publications
1 December 2005 in Nature
Verified
Journal Article
Closed access
PDF file
MSMahesh Sankaran
Mahesh Sankaran
NHNiall Hanan
Niall Hanan
RSRobert Scholes
Robert Scholes
JRJayashree Ratnam
Jayashree Ratnam
DADavid Augustine
David Augustine
NZNick Zambatis
Nick Zambatis

1 October 1998 in The Journal of Wildlife Management
Verified
Journal Article
Closed access
DADavid Augustine
David Augustine
SMSamuel J. McNaughton
Samuel J. McNaughton

12 February 2004 in Journal of Applied Ecology
Verified
Journal Article
Closed access
PDF file
DADavid Augustine
David Augustine
SMSamuel J. Mcnaughton
Samuel J. Mcnaughton

1 October 2003 in Ecological Applications
Verified
Journal Article
Open access
PDF file
DADavid Augustine
David Augustine
SMSamuel J. McNaughton
Samuel J. McNaughton
DFDouglas A. Frank
Douglas A. Frank
Small‐scale fertilization experiments have shown that soil nutrients limit plant productivity in many semiarid grasslands and savannas, but linkages among nutrients, grasses, and grazers are rarely studied in an ecosystem context. We used hectare‐scale heterogeneity in soil nutrients created by cattle management practices within a geologically homogeneous savanna to examine relationships among soil nitrogen and phosphorus, aboveground net primary production (ANPP), grass nutrient content, and a mixed community of native and domestic herbivores on central Kenyan rangeland. Increasing soil N and P content was consistently associated with increasing plant productivity and rainfall use efficiency in wet, dry, and drought years. A fertilization experiment and analyses of grass N:P ratios across sites indicated that N is the primary limiting nutrient on nutrient‐rich glades, whereas N and P co‐limit productivity on nutrient‐poor bushland sites. Variation in ANPP among patches within the landscape was linearly correlated with consumption rates of large herbivores. Grazing pressure was consistently high (>60% of ANPP) at all but one site in a dry year (1999), and was greater in nutrient‐rich glades (73 ± 4% of ANPP) than in nutrient‐poor bushland sites (43 ± 7% of ANPP) in a wet year (2001). Grasses of nutrient‐rich sites contained sufficient P concentrations to meet requirements for pregnant and lactating ungulates, whereas grasses in nutrient‐poor swards were P deficient. Even though native and domestic herbivores selectively used and intensively grazed nutrient‐rich sites, productivity on these sites remained high throughout the study. Analyses of nitrogen budgets for nutrient‐rich and nutrient‐poor sites showed that large herbivores themselves caused a net N input to the former and a net N loss from the latter. Thus, large herbivores not only respond to heterogeneity in soil and plant nutrients across the landscape, but also play a role in maintaining the N‐enriched status of highly productive and intensively grazed sites.


1 March 2009 in Rangeland Ecology & Management
Verified
Journal Article
Closed access
JDJustin D. Derner
Justin D. Derner
WLWilliam K. Lauenroth
William K. Lauenroth
PSPaul Stapp
Paul Stapp
DADavid Augustine
David Augustine