Topography drives tree–habitat association and functional and phylogenetic structure in the northernmost tropical dry forest of the Americas

ABSTRACT

Background

Plant species composition and structural attributes are related to physiographic factors such as slope orientation and topographic position. This relationship is accentuated with increasing seasonality in temperature and precipitation.

Aims

We quantified the relationship between topography and the taxonomic, functional and phylogenetic community composition of woody species at the northernmost distribution of seasonally dry tropical forests (STDF) in the Americas.

Methods

We related slope orientation (north-facing vs. south-facing) and position (upper slope vs. lower slope) to the distribution of species, assessed their habitat preference by life stage (juvenile vs. adult) and compared the observed phylogenetic distance of species against random species assemblages.

Results

Our results showed the segregation of two species groups in both life stages is related to slope orientation, but not to topographic position. We found a strong habitat association for 68% of the species with both juveniles and adults similarly associated with the same habitat. Slope orientation was related to taxonomic, functional and phylogenetic structure, but it differed in the two life stages.

Conclusions

The functional and evolutionary segregation of species between north-facing vs. south-facing habitats indicates that species are non-randomly distributed; suggesting that deterministic mechanisms (e.g. topographic habitat specialisation) are operating at a local scale.

Highlights

• Slope orientation drives the species-habitat association, and functional/phylogenetic structure of the northernmost tropical dry forests on the American continent.

• Juveniles and adults of tree species share similar habitat association patterns, conserving habitat preference.

• In both life stages, the functional and phylogenetic structure of trees was clearly differentiated between north-facing and south-facing slopes, but similar within each slope.

• Dry forest tree species are non-randomly distributed among topographic habitats.

• The contrasting periods of water availability in the soil and solar radiation between slopes have revealed emerging patterns of topographic habitat specialisation.

KEYWORDS:

• Community-weighted mean
• habitat specialisation
• phylogenetic beta-diversity
• physiographic factors
• tree life stages

Acknowledgments

The authors acknowledge Reserva Ecológica Monte Mojino (REMM), an initiative from Nature and Culture International in collaboration with Naturaleza y Cultura Sierra Madre, A.C. We especially thank Miguel Angel Mata and their excellent staff of the Alamos office. Local people, especially Leocadio García and Gabriel Figueroa from Sabinito, also helped during fieldwork. Finally, we thank the APFF-Sierra de Álamos-Río Cuchujaqui, especially Alma Leonor Montaño and DGVS- SEMARNAT for their help and permits.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplementary data

Supplemental data for this article can be accessed online at https://doi.org/10.1080/17550874.2023.2286233.

Additional information

Funding

This research was funded by Coordinación de la Investigación Científica-Universidad Michoacana de San NIcolás de Hidalgo (UMSNH 2017-13001256) and Consejo Nacional de Humanidades, Ciencias y Tecnologías (CONAHCYT-Ciencia Básica No. 243010) granted to LLT and SPH. AQM held a CONAHCYT Master’s Scholarship (No. 462862) at Maestría en Ciencias en Ecología Integrativa (UMSNH) and Beca Mixta for a research stay at Universidad of Alaska-Fairbanks. While writing this paper, LLT held a Visiting Fellow position at the Yale School of the Environment with support from UMSNH No. 13001256) and CONAHCYT (Grant No. 100388).