The influence of climate on the spatial patterning of Neotropical plant families

Abstract

Aim Climate is recognized for the significant role it plays in the global distribution of plant species diversity. We test the extent to which two aspects of climate, namely temperature and precipitation, explain the spatial distribution of high taxonomic groupings (plant families) at a regional spatial resolution (the Neotropics). Our goal is to provide a quantitative and comparative framework for identifying the local effects of climate on the familial composition of tropical forests by identifying the influence of climate on the number of individuals and the number of species within a given family.Location One hundred and forty-four 0.1-ha forest transect sites from the Neotropics (19.8°N-27.0°S and 40.1°W-105.1°W). Data were originally collected by A.H. Gentry.Methods Spatial variability in the abundance (density) and species richness of 159 tropical plant families across a range of predominately lowland Neotropical landscapes were attributed to eight temperature and precipitation measures using the eigen analysis method of two-field joint single-value decomposition.Results Climate significantly affects the within-clade diversity of several ecologically important Neotropical plant families. Intrafamily abundance and richness covary with temperature in some families (e.g. Fabaceae) and with precipitation in others (e.g. Bignoniaceae, Arecaceae), with differing climatic preferences observed even among co-occurring families. In addition, the familylevel composition of Neotropical forests, in both abundance and richness, appears to be influenced more by temperature than by precipitation. Among lowland families, only Asteraceae increased in species richness with decreasing temperature, although several families, including Melastomataceae and Rubiaceae, are more abundant at lower temperatures.Main conclusions Although plant diversity is known to vary as a function of climate at the species level, we document clear climatic preferences even at the rank of family. Temperature plays a stronger role in governing the familial composition of tropical forests, particularly in the richness of families, than might be expected given its narrow annual and diurnal range in the tropics. Although other environmental or geographic variables that covary with temperature may be more causally linked to diversity differences than temperature itself, the results nonetheless identify the taxonomic components of tropical forest composition that may be most affected by future climatic changes.

Decoupling the spread of grasslands from the evolution of grazer-type herbivores in South America

“…Tree cover in savannahs is determined mainly by annual rainfall and rainfall seasonality 50 , hence, the slight increase in open-habitat grasses over trees may suggest drier local climates. This scenario is consistent with the lower abundance of palms 20 . Alternatively, the increase in open-habitat grasses and, by inference, openness may relate to intensified disturbance in the form of ash fall, fire or herbivore pressure 51 .…”

“…Both paleobotanical data and some fauna-based proxies further strongly suggest that these habitats were closed. The high frequency in phytolith assemblages of palms, which today are most abundant and diverse in humid forests and wetlands 20,21 , combined with the presence of zingiberaleans and/or closedhabitat grasses evident in phytolith assemblages until at least the early Oligocene indicates a landscape dominated by humid forest vegetation; similarly, the taxa that dominate macro-and palynofloras suggest closed forests growing under wet climates until at least the late Oligocene 13 , as do cenogram analysis of South American fossil faunas 22 . Local environments appear to have become patchier in the early Miocene (Fig.…”

Structure and floristic similarities of upper montane forests in Serra Fina mountain range, southeastern Brazil

“…This is a very similar pattern with other tropical montane cloud forests (Madsen & Ollgaard 1994;Kelly et al 1994;Hamilton et al 1995). Fabaceae, one the most species rich families, mainly occurs in the seasonal and ombrophilous forests at lower altitudes, showed the lowest phytosociologic importance in AUMF (Yamamoto et al 2005;Meireles et al 2008;Punyasena et al 2008).…”

Estimating Neotropical palaeotemperature and palaeoprecipitation using plant family climatic optima

“…The recognized relationship between the climate of a region and its resident plants makes botanical remains a useful tool of palaeontologists and Quaternary scientists in the reconstruction of palaeoclimate. Comparative assessments of family-level biogeographic patterns indicate that even large families demonstrate climatic preferences (Punyasena et al, 2008). This study determines the extent of that specificity and demonstrates its applicability to palaeoclimate reconstructions.…”

“…The data include 154 families in total (Table 1). The taxonomic identification of individuals within the transect data were corrected and revised as described in Punyasena et al (2008). In addition, six optional APG II synonymies were revised: Cochlospermaceae (Bixaceae); Krameriaceae (Zygophyllaceae); Quiinaceae (Ochnaceae); Rhizophoraceae (Erythroxylaceae); Trigoniaceae (Chrysobalanaceae); and Valerianaceae (Caprifoliaceae).…”