Effects of Growth Form and Functional Traits on Response of Woody Plants to Clearing and Fragmentation of Subtropical Rainforest

Abstract

The conservation implications of large-scale rainforest clearing and fragmentation on the persistence of functional and taxonomic diversity remain poorly understood. If traits represent adaptive strategies of plant species to particular circumstances, the expectation is that the effect of forest clearing and fragmentation will be affected by species functional traits, particularly those related to dispersal. We used species occurrence data for woody plants in 46 rainforest patches across 75,000 ha largely cleared of forest by the early 1900s to determine the combined effects of area reduction, fragmentation, and patch size on the taxonomic structure and functional diversity of subtropical rainforest. We compiled species trait values for leaf area, seed dry mass, wood density, and maximum height and calculated species niche breadths. Taxonomic structure, trait values (means, ranges), and the functional diversity of assemblages of climbing and free-standing plants in remnant patches were quantified. Larger rainforest patches had higher species richness. Species in smaller patches were taxonomically less related than species in larger patches. Free-standing plants had a high percentage of frugivore dispersed seeds; climbers had a high proportion of small wind-dispersed seeds. Connections between the patchy spatial distribution of free-standing species, larger seed sizes, and dispersal syndrome were weak. Assemblages of free-standing plants in patches showed more taxonomic and spatial structuring than climbing plants. Smaller isolated patches retained relatively high functional diversity and similar taxonomic structure to larger tracts of forest despite lower species richness. The response of woody plants to clearing and fragmentation of subtropical rainforest differed between climbers and slow-growing mature-phase forest trees but not between climbers and pioneer trees. Quantifying taxonomic structure and functional diversity provides an improved basis for conservation planning and management by elucidating the effects of forest-area reduction and fragmentation. Efectos de la Forma de Crecimiento y Atributos Funcionales en la Respuesta de Plantas Leñosas al Desmonte y Fragmentación de Bosque Lluvioso Subtropical.

Wood density, growth and mortality relationships of lianas on environmental gradients in fragmented forests of montane landscapes

“…However, strong conclusions about the influence of fragmentation cannot be drawn from our study, the fragmentation variable explaining very little variability in our data set. The diversity of lianas can increase (Mohandass, Hughes, Campbell, & Davidar, ; Schnitzer & Bongers, ; Zhu et al., ) or decrease with fragmentation (Addo‐Fordjour, Rahmad, & Shahrul, ; Arroyo‐Rodrıguez & Toledo‐Aceves, ; Benítez‐Malvido & Martínez‐Ramos, ; Kooyman et al., ), but we found no pattern regarding species richness. As a case study, our site has certain characteristics that may reduce the signal of fragmentation, such as relatively recent fragmentation (less than two decades), different vegetation types around the various fragments, and steep and variable landscapes, all of which limit generalization from our results.…”

Functional attributes change but functional richness is unchanged after fragmentation of Brazilian Atlantic forests

“…; Petchey & Gaston ; Villéger, Mason & Mouillot ; Kooyman et al . ). Functional diversity quantifies a range of functional traits within multidimensional niche space, typically focusing on the physiological and morphological traits that define a species' ecological role in a community (Petchey & Gaston ; Villéger, Mason & Mouillot ) and yielding a single continuous measure.…”

Seedling growth rates and light requirements of subtropical rainforest trees associated with basaltic and rhyolitic soils

“…Our selection represents only a small fraction of typical tree species richness in Australian subtropical rainforests, especially the diverse assemblages found on basalt (Floyd 1989;Royer et al 2009). However, we believe that our selection included the most shade-tolerant, common tree species on both substrate types, our choice being based on experience sampling in Nightcap National Park, NSW (Lusk et al 2010;Kooyman et al 2013; K. M. Sendall, P. B. Reich and C. H. Lusk, unpubl. data).…”