Multiple Factors Influence Seasonal and Interannual Litterfall Production in a Tropical Dry Forest in Mexico

Hernán Morffi-Mestre,Gregorio Ángeles-Pérez,José Luis Andrade,Jennifer S. Powers,Francisco Chi-May,Juan Manuel Dupuy,Astrid Helena Huechacona Ruiz,Filogonio May-Pat

doi:10.3390/f11121241

Abstract

Litterfall production plays a fundamental role in the dynamics and function of tropical forest ecosystems, as it supplies 70–80% of nutrients entering the soil. This process varies annually and seasonally, depending on multiple environmental factors. However, few studies spanning several years have addressed the combined effect of climate variables, successional age, topography, and vegetation structure in tropical dry forests. In this study, we evaluated monthly, seasonal, and annual litterfall production over a five-year period in semideciduous dry forests of different successional ages growing on contrasting topographic conditions (sloping or flat terrain) in Yucatan, Mexico. Its relationship with climate and vegetation structural variables were also analyzed using multiple linear regression and generalized linear models. Litterfall was measured monthly in 12 litterfall traps of 0.5 m2 in three sampling clusters (sets of four 400 m2 sampling plots) established in forests of five successional age classes, 3–5, 10–17, 18–25, 60–79, and >80 years (in the latter two classes either on slopping or on flat terrain), for a total of 15 sampling clusters and 180 litterfall traps. Litterfall production varied between years (negatively correlated with precipitation), seasons (positively correlated with wind speed and maximum temperature), and months (negatively correlated with relative humidity) and was higher in flat than in sloping sites. Litterfall production also increased with successional age until 18–25 years after abandonment, when it attained values similar to those of mature forests. It was positively correlated with the aboveground biomass of deciduous species but negatively correlated with the basal area of evergreen species. Our results show a rapid recovery of litterfall production with successional age of these forests, which may increase with climate changes such as less precipitation, higher temperatures, and higher incidence of hurricanes.

Highlights

Litterfall production is a key process of the carbon cycle in terrestrial ecosystems [1,2,3,4,5]
Based on the relationships between litterfall production and climatic variables considered in our study, under this climate change scenario, an increase in both the proportion of deciduous species and litterfall production would be expected in the tropical dry forests (TDF) that we examined, but not necessarily in the rate of litter decomposition, due to the likely adverse effects of the altered environmental conditions on decomposers
Successional age, seasonality, and topography are drivers of litterfall production. This production was higher in the dry season, increased with successional age, and was positively correlated with the aboveground biomass of deciduous species and negatively with the basal area of evergreen species

Summary

Introduction

Litterfall production (amount of plant material that falls to the ground per unit area and time) is a key process of the carbon cycle in terrestrial ecosystems [1,2,3,4,5]. It is the main source of reincorporation. Most studies conducted to date on litterfall production in TDF have been short-term [24,25], but see [26,27,28], which limit the possibility of evaluating, modeling, and predicting the effects of climate change. The few multi-year studies of litterfall production in TDF and its relationship with precipitation [29] have documented several patterns of monthly litterfall production with one, two, or irregular peaks at different times of the year [16,19], mostly associated with scarce or nil precipitation [16,19,30]

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