Myster R.W.

Ecosystem Development and Plant Succession on Landslides in the Caribbean

Ecosystem Development and Plant Succession on Landslides in the Caribbean
Lawrence R. Walker, Daniel J. Zarin, Ned Fetcher, Randall W. Myster and Arthur H. Johnson
Biotropica
Vol. 28, No. 4, Part A. Special Issue: Long Term Responses of Caribbean Ecosystems to Disturbances (Dec., 1996), pp. 566-576

Abstract: 
Landslides are common in mountainous regions of the Caribbean and are triggered by heavy rains and earthquakes, and often occur in association with human disturbances (e.g., roads). Spatially heterogeneous removal of both substrate and vegetation is responsible for a variety of patterns of ecosystem development and plant successional trajectories within Caribbean landslides. Soil nutrient pools in exposed mineral soils reach levels comparable to mature forest soils within 55 yr but soil organic matter recovers more slowly. Plant colonization of landslides depends on the availability of propagules and suitable sites for germination, soil stability, and the presence of residual or newly deposited soil organic matter and associated nutrients. Once initial colonization occurs, the rate and trajectory of plant succession on landslides is strongly affected by plant/plant interactions. We present two conceptual models of landslide succession that summarize the major processes and pathways of ecosystem development and plant succession on landslides. Additional work is needed to characterize interactions between spatially heterogeneous zones, controls over soil development, impacts of key plant species, and the role of animals on Caribbean landslides.

predicting landslide vegetation in patches on landscape gradients in puerto rico

Myster, R.W., Thomlinson, J.R., and Larsen, M.C., 1997, Predicting landslide vegetation in patches on landscape gradients in Puerto Rico: Landscape Ecology, v. 12 p. 299-307.

Abstract: 
We explored the predictive value of common landscape characteristics for landslide vegetative stages in the LuquilloExperimental Forest of Puerto Rico using four different analyses. Maximum likelihood logistic regression showed that aspect, age, and substrate type could be used to predict vegetative structural stage. In addition it showed that the structural complexity of the vegetation was greater in landslides (1) facing the southeast (away from the dominant wind direction of recent hurricanes), (2) that were older, and (3) that had volcaniclastic rather than dioritic substrate. Multiple regression indicated that both elevation and age could be used to predict the current vegetation, and that vegetation complexity was greater both at lower elevation and in older landslides. Pearson product-moment correlation coefficients showed that (1) the presence of volcaniclastic substrate in landslides was negatively correlated with aspect, age, and elevation, (2) that road association and age were positively correlated and (3) that slope was negatively correlated with area. Finally, principal components analysis showed that landslides were differentiated on axes defined primarily by age, aspect class, and elevation in the positive direction, and by volcaniclastic substrate in the negative direction. Because several statistical techniques indicated that age, aspect, elevation, and substrate were important in determining vegetation complexity on landslides, we conclude that landslide succession is influenced by variation in these landscape traits. In particular, we would expect to find more successional development on landslides which are older, face away from hurricane winds, are at lower elevation, and are on volcaniclastic substrate. Finally, our results lead into a hierarchical conceptual model of succession on landscapes where the biota respond first to either gradients or disturbance depending on their relative severity, and then to more local biotic mechanisms such as dispersal, predation and competition.
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