Biodiversity in tropical plantations is influenced by surrounding native vegetation but not yield: A case study with dung beetles in Amazonia

Abstract

Human-modified forests, including plantations and managed forest, will be a major component of tropical landscapes in the near future. To conserve biodiversity across modified tropical landscapes we must first understand what influences diversity in planted areas. We studied dung beetle communities in Eucalyptus plantations to assess the influence of local (canopy openness and soil texture) and landscape factors (surrounding native forest cover) on taxonomic and functional diversity, and to determine whether biodiversity in plantations is affected by timber production. Dung beetle community composition in Eucalyptus plantations was largely explained by the surrounding native forest cover, as Simpson's diversity and functional diversity (Rao's quadratic entropy) increased with the extent of native forest in buffer areas. However, the abundance of dung beetle species associated with undisturbed forest was not explained by any of the explanatory variables. The coarse sand content of the soil explained much of the functional similarity between plantations and native forests, as well as variation in dung beetle community structure. The total abundance of dung beetles in plantations increased with coarse sand content, whereas body mass declined, and dung beetle abundance and functional originality decreased with canopy openness. Timber production intensity did not explain the variation in any of the measured diversity parameters. If enhancing biodiversity in plantations is a management goal, then these results highlight the importance of restoring or retaining native forest areas in modified landscapes. They also suggest that integrated management could improve biodiversity in Eucalyptus plantations without reducing timber production.

Primary forest loss and degradation reduces biodiversity and ecosystem functioning: A global meta‐analysis using dung beetles as an indicator taxon

“…These findings agree with investigations based on different faunal taxa that demonstrate the loss of species richness and abundance in response to undisturbed primary forest conversion (see Barlow et al, 2007; Castaño‐Villa et al, 2019; Gibson et al, 2011). Undisturbed primary forest conversion and consequent creation of degraded primary forest, secondary forest, forestry plantations or forestry restoration drives different micro‐habitat characteristics to those of undisturbed primary forests, such as a reduced basal area and increased canopy opening (Audino et al, 2017; Barlow et al, 2007; Beiroz et al, 2019; Culot et al, 2013; Parry et al, 2007), a larger percentage of coarse sand in the soil (associated with the degree of soil compaction), lower soil moisture content and higher temperatures (Beiroz et al, 2019; Senior et al, 2017). Furthermore, these coverages may have lower excrement availability due to large vertebrates' defaunation compared to undisturbed primary forests (Barlow et al, 2007; Fuzessy et al, 2021; Parry et al, 2007).…”

Evaluating Plantation Forest vs. Natural Forest Regeneration for Biodiversity Enhancement in Hong Kong

“…In tropical and sub-tropical Australia, plantations, whether of single or mixed species, were considered to have strongly positive consequences for restoring biodiversity in heavily cleared landscapes [19]. However, this viewpoint is countered by another study in tropical Australia, where dung beetles, considered to be useful environmental indicators, showed lower species diversity and numbers, in plantations than in native forest [20]. Furthermore, in a summary of research papers on south-east Asia, where plantation forests have increased by approximately 1.3% annually since 2010 [1], all types of non-oil palm plantations were shown to be inferior to naturally regenerating forest in species richness and abundance [21].…”

Tropical forest dung beetle–mammal dung interaction networks remain similar across an environmental disturbance gradient

“…Dung beetle community responses to forest disturbance have been well documented (Nichols et al., 2007; Nichols, Uriarte, Bunker, et al., 2013). They tend to be minimally affected by selective, low‐intensity logging (Franca et al., 2017; Slade et al., 2011), but to undergo altered community composition and the loss of certain functional groups in monocultural plantations (Beiroz et al., 2019; Gray et al., 2014). Indeed, land‐use changes and defaunation have strong effects on dung beetle communities globally, reducing overall abundance, richness, diversity and mean body size (Fuzessy et al., 2021).…”