Photos from the Field: Whitfield et al. Sucession in New Guinea’s Lowlands

Whitfeld, T. J. S., Lasky, J. R., Damas, K., Sosanika, G., Molem, K. and Montgomery, R. A. (2014), Species Richness, Forest Structure, and Functional Diversity During Succession in the New Guinea Lowlands. Biotropica, 46: 538–548. doi: 10.1111/btp.12136

Much of the world’s tropical forests have been affected by anthropogenic disturbance. These forests are important biodiversity reservoirs whose diversity, structure and function must be characterized across the successional sequence. We examined changes in structure and diversity along a successional gradient in the lowlands of New Guinea. To do this, we measured and identified all stems ≥5 cm diameter in 19 0.25 ha plots ranging in age from 3 to >50 yr since disturbance. We also measured plant functional traits related to establishment, performance, and competitive ability. In addition, we examined change in forest structure, composition, species diversity, and functional diversity through succession. By using rarefaction to estimate functional diversity, we compared changes in functional diversity while controlling for associated differences in stem and species density. Basal area and species density increased with stand age while stem density was highest in intermediate secondary forests. Species composition differed strongly between mature and secondary forests. As forests increased in basal area, community-weighted mean wood density and foliar carbon increased, whereas specific leaf area and proportion of stems with exudate decreased. Foliar nitrogen peaked in medium-aged forests. Functional diversity was highest in mature forests, even after accounting for differences in stem and species diversity. Our study represents one of the first attempts to document successional changes in New Guinea’s lowland forest. We found robust evidence that as succession proceeds, communities occupy a greater range of functional trait space even after controlling for stem and species density. High functional diversity is important for ecological resiliency in the face of global change.

For more information visit: Timothy Whitfeld’s Home Page, The Brown University Herbarium, and The New Guinea Binatang Research Center.

 

Intsia bijuga (Fabaceae), one of the mature forest canopy tree species in the Wanang Conservation Area

Intsia bijuga (Fabaceae), one of the mature forest canopy tree species in the Wanang Conservation Area

Wanang Conservation Area, Papua New Guinea. Clan leaders opted to protect 10,000 ha of their forest as logging activity in the area increased.

Wanang Conservation Area, Papua New Guinea. Clan leaders opted to protect 10,000 ha of their forest as logging activity in the area increased.

Field crew, from left to right: Gibson Sosanika (co-author), Jori Umbang, Tom, Markus Dugam, Billy Bau

Field crew, from left to right: Gibson Sosanika (co-author), Jori Umbang, Tom, Markus Dugam, Billy Bau

Field camp in the Wanang Conservation Area, Papua New Guinea

Field camp in the Wanang Conservation Area, Papua New Guinea

The area's steep slopes and rugged topography make it subject to frequent landslides and other natural disturbances.

The area’s steep slopes and rugged topography make it subject to frequent landslides and other natural disturbances.