Co-Authors:
Sheffer, E., Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Robert H. Smith Faculty of Agriculture, Hebrew University of Jerusalem, P.O. Box 12, Rehovot 76100, Israel, Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544, United States
Canham, C.D., Cary Institute of Ecosystem Studies, Box AB, Millbrook, NY 12545, United States
Kigel, J., Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Robert H. Smith Faculty of Agriculture, Hebrew University of Jerusalem, P.O. Box 12, Rehovot 76100, Israel
Perevolotsky, A., Department of Agronomy and Natural Resources, Institute of Plant Sciences, Agricultural Research Organization, the Volcani Center, P.O. Box 6, Bet Dagan 50250, Israel
Abstract:
Plant colonization studies usually address density-dependent processes in the narrow sense of recruitment constraints due to negative density-dependent seed and seedling mortality. However, complex density-dependent effects may be involved in additional stages of the recruitment process. We hypothesized that seed arrival and seedling establishment are influenced by density dependence acting at small scales at the site of colonization, and at larger scales as a function of the colonizing species' landscape abundance. These hypotheses were tested in a study of colonization of pine forests by oaks in a heterogeneous Mediterranean landscape. Maximum-likelihood models show that density effects switch from positive to negative along the range of landscape-scale oak seed source abundance. Contrary to expectations, high seed source densities limited oak recruitment, suggesting a landscape-scale Janzen-Connell effect. We propose a range of mechanisms that generate positive or negative density dependence during colonization, resulting in nonlinear density-dependent feedbacks that can generate unexpected colonization patterns. © 2013 by the Ecological Society of America.
תפריט נגישות
ניגודיות עדינה
מונוכרום
הדגשת קישורים
חסימת אנימציה
פונט קריא
סגור
איפוס הגדרות נגישות
להורדת מודול נגישות חינם
