Multidimensional trade‐offs in species responses to disturbance: implications for diversity in a subtropical forest

Abstract

Abstract. Species employ diverse strategies to cope with natural disturbance, but the importance of these strategies for maintaining tree species diversity in forests has been debated. Mechanisms that have the potential to promote tree species coexistence in the context of repeated disturbance include life history trade-offs in colonization and competitive ability or in species' ability to survive at low resource conditions and exploit the temporary resourcerich conditions often generated in the wake of disturbance (successional niche). Quantifying these trade-offs requires long-term forest monitoring and modeling.We developed a hierarchical Bayes model to investigate the strategies tree species employ to withstand and recover from hurricane disturbance and the life history trade-offs that may facilitate species coexistence in forests subject to repeated hurricane disturbance. Unlike previous approaches, our model accommodates temporal variation in process error and observations from multiple sources. We parameterized the model using growth and mortality data from four censuses of a 16-ha plot taken every five years (1990)(1991)(1992)(1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005), together with damage data collected after two hurricanes and annual seed production data (1992)(1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005).Species' susceptibilities to hurricane damage as reflected by changes in diameter growth and fecundity immediately following a storm were weak, highly variable, and unpredictable using traditional life history groupings. The lower crowding conditions (e.g., high light) generated in the wake of storms, however, led to greater gains in growth and fecundity for pioneer and secondary-forest species than for shade-tolerant species, in accordance with expectation of life history. We found moderate trade-offs between survival in high crowding conditions, a metric of competitive ability, and long-distance colonization. We also uncovered a strong trade-off between mean species fecundity in low crowding conditions, a metric of recovery potential, and competitive ability. Trade-offs in competitive and colonization ability, in addition to successional niche processes, are likely to contribute to species persistence in these hurricaneimpacted forests. The strategies species employ to cope with hurricane damage depend on the degree to which species rely on sprouting, repair of adult damage, changes in demographic rates in response to enhanced resource availability after storms, or long-distance dispersal as recovery mechanisms.

Seven-year responses of trees to experimental hurricane effects in a tropical rainforest, Puerto Rico

“…This later aspect reveals the longterm impact of Hurricane Georges (1998), the last severe storm to strike our site, on the background dynamics of the forest mosaic, and contributes to our understanding of the role of hurricanes in regulating long-term (i.e., decadal) variation in the species composition of hurricane-driven forests (Crow, 1980;Lugo et al, 2000). These results are also consistent with our understanding of the role of hurricanes in maintaining species with contrasting life histories demonstrating resistance versus resilience to hurricane disturbance (Zimmerman et al, 1994;Boucher et al, 1994;Uriarte et al, 2012). As monitoring of the CTE proceeds, we will be able to determine to what degree pioneer species regulate successional processes of the forest.…”

“…Integrating two-decades of change in community composition over large spatial scales in the 16 ha Luquillo Forest Dynamics Plot (which lies adjacent to the CTE blocks; Shiels and González, 2014), produced a clear community response that was used to measure the grain of the disturbance . Moreover, quantitative studies from the LFDP clearly demonstrate an ability to detect unique life history characteristics of species responding to hurricane disturbance (Zimmerman et al, 1994;Uriarte et al, 2010;2012). But, to experimentally test hurricane effects at anywhere near the scale of the LFDP would be logistically difficult (if not impossible) and, in the end, we chose to balance the trade-off between scale of treatment and the difficulties of interpreting an unreplicated experiment (Barker Plotkin et al, 2013).…”

“…The theory assumes trade-offs either in species competitive abilities or niche partitioning whereby more recently disturbed forest patches serve as opportunities for the establishment of rapidly growing, shade intolerant guild of pioneer species that persist in a community dominated by slower-growing species tolerant of low resource conditions (Pacala and Rees, 1998;Uriarte et al, 2012). To the degree that the presence of two (or more) generalized species groups with different light requirements overlap in space and time (Miller et al, 2011), species diversity of local, recently disturbed forest patches will reach a maximum before declining, as shade tolerant species come to dominate the patch.…”

“…In particular, we wish to investigate the generality of our previous observations by utilizing ordination methods to illuminate the responses of all species in the forest community, not just the most common species as was analyzed by Shiels et al (2010). This approach would support the goal of understanding diversity responses to the manipulations in the context of trade-offs in species resistance and resilience to hurricane disturbance (Boucher et al, 1994;Zimmerman et al, 1994;Burslem and Whitmore, 1999;Tanner and Bellingham, 2006;Uriarte et al, 2012).…”

Species‐specific transpiration responses to intermediate disturbance in a northern hardwood forest

“…Nonstand replacing disturbances, often called intermediate disturbances, occur naturally via species-specific pest infestation [e.g., Herms and McCullough, 2014;Simard et al, 2012], strong storms and wind throws [e.g., Uriarte et al, 2012], drought [e.g., Huang and Anderegg, 2012;McDowell et al, 2008;Royer et al, 2010], and ecological succession [e.g., Gough et al, 2013;Hardiman et al, 2013] and anthropogenically via fire management and biomass removals [e.g., Royer et al, 2010;Stephens et al, 2009] and selective logging [e.g., Asase et al, 2014;Asner et al, 2004]. These disturbances impact canopy structure at a diffuse spatial scale ranging from one to several tree crowns per hectare, and may be distributed over MATHENY ET AL.…”