The high value of logged tropical forests: lessons from northern Borneo

Abstract

The carbon storage and conservation value of old-growth tropical forests is clear, but the value of logged forest is less certain. Here we analyse[100,000 observations of individuals from 11 taxonomic groups and [2,500 species, covering up to 19 years of post-logging regeneration, and quantify the impacts of logging on carbon storage and biodiversity within lowland dipterocarp forests of Sabah, Borneo. We estimate that forests lost ca. 53% of above-ground biomass as a result of logging but despite this high level of degradation, logged forest retained considerable conservation value: floral species richness was higher in logged forest than in primary forest and whilst faunal species richness was typically lower in logged forest, in most cases the difference between habitats was no greater than ca. 10%. Moreover, in most studies [90% of species recorded in primary forest were also present in logged forest, including species of conservation concern. During recovery, logged forest accumulated carbon at five times the rate of natural forest (1.4 and 0.28 Mg C ha -1 year -1 , respectively). We conclude that allowing the continued regeneration of extensive areas of Borneo's forest that have already been logged, and are at risk of conversion to other land uses, would provide a significant carbon store that is likely to increase over time. Protecting intact forest is critical for biodiversity conservation and

Responses of Soil Fungi to Logging and Oil Palm Agriculture in Southeast Asian Tropical Forests

“…In a recent comprehensive meta-analysis from lowland tropical forests around the globe, nearly 85 % of macroscopic taxa such as mammals and birds were retained in once-logged forests [39]. Microbes were not included in the meta-analysis, probably due to the paucity of studies in the literature, but the suitability of logged forests for maintaining diverse populations of soil microbes merits further investigation, as logged forests are often considered "degraded" and, therefore, are vulnerable to conversion to oil palm plantations [38,76]. The similarity in extracellular enzyme potential across forest soils further supports the notion that regenerating forests maintain a high degree of ecosystem functionality and may cycle nutrients at similar rates to primary forests.…”

“…Therefore, a loss of EcM fungal inoculum from soils may impede the regeneration of these forests [36], which will lead to cascading extinctions across other trophic groups dependent on dipterocarp forests for survival. Dipterocarp trees are economically valuable for timber, and, consequently, logging has been a major contributor to forest degradation in this region [37] with Malaysia accounting for a significant portion to the global total of tropical timber exports [38]. The most obvious alteration to primary forest by logging is the removal of large, commercially valuable trees, which will adversely affect hostspecialist mycorrhizal fungi and substrate-specific fungal decomposers.…”

Biogeography and conservation in Southeast Asia: how 2.7 million years of repeated environmental fluctuations affect today’s patterns and the future of the remaining refugial-phase biodiversity

“…More detailed projections for three forest types under this and other paleoclimatic models are provided by Cannon et al (2009) In Southeast Asia temperature variation is less significant in determining the growing season and the natural vegetation than rainfall and its seasonality. The region's characteristic seasonal (monsoonal) climate developed after the rise of the Tibetan plateau (*30 Ma) and the closure of the seaway between the Australian and Asian plates (*15 Ma) and intensified *10 Ma (Morley 2007;Berger 2009). The frequent interruption of this seasonality by ENSOs became significant 3-5 Mya.…”

“…Plant distribution and phenology is associated with rainfall seasonality and variability, and animals in turn tend to track plant productivity (see Brockelman 2010 for a recent discussion of the implications of seasonality at one site). This annual monsoonal pattern has been disrupted by ENSO events every 4-6 years (during in the 20th century) that are associated with drought and increased fire frequency (e.g., 1997-8, 2006-7) (Berger 2009;Taylor 2010). There are also super-droughts, some associated with *40 year global drought cycles and others with 10-15 years concordance of ENSO and Indian Ocean dipole cycles.…”

Functional structure of ant and termite assemblages in old growth forest, logged forest and oil palm plantation in Malaysian Borneo

“…Berry et al 2010;Edwards et al 2011) many taxa are strongly affected by disturbance. For example, a review of bird responses to tropical forest disturbance (Gray et al 2007) found significant declines in richness and abundance of insectivores, omnivores and frugivores, although increases in granivores.…”