Influence of reduced‐impact logging on Central Amazonian bats using a before‐after‐control‐impact design

Abstract

Tropical forests contain the highest concentration of species in terrestrial ecosystems. However, they are disappearing rapidly due to forest clearing to extract timber illegally. Reduced-impact logging (RIL) is one of the main sustainability proposals for earning profits while still promoting biodiversity conservation. In the present study, we test the impacts of RIL on biodiversity and use the results to draw conclusions regarding the capacity of RIL to deliver conservation goals whilst also enabling minimal biodiversity impacts. We used a before-after-control-impact (BACI) study to assess the effects of RIL on a bat assemblage in Central Amazon. We sampled unlogged (control) and RIL areas before and after timber extraction. We also tested the relationship between forest canopy openness and bat assemblage before and after logging. For 64 nights, we captured 706 individuals of 33 Phyllostomidae species. Sampling time influenced total bat composition and phytophagous bat composition, both in logged and control sites. The time 9 site interaction influenced animalivorous bat composition and reduced the abundance and richness of animalivorous species in RIL sites. Sampling time, site, and the time 9 site interaction did not influence the number of species, total abundance, or phytophague abundance. The canopy was, on average, 3.4 times more open after the RIL and influenced animalivorous composition. Our results indicate that species sensitive to environmental changes, such as animalivorous bats, respond rapidly to forest logging. In more opportunistic guilds, such as phytophagues, the temporal change in the species composition in control and logged sites indicate that other temporal factors, besides logging, may have influenced bat assemblages. We suggest that RIL timber certification stimulates the protection of primary forest without logging within the area under exploration, which is not the case in the area we studied. We also recommend the application of BACI designs and monitoring environmental metrics in RIL impact studies.

The impact of a run‐of‐the‐river hydroelectric dam on a non‐volant small‐mammal assemblage in Brazilian Amazonia

“…The importance of the flooded areas to regional population dynamics of the species involved will depend on the conservation of the unflooded areas, and the transport infrastructure associated with dam construction may increase regional deforestation (Fearnside, 2014). Therefore, we recommend conducting long‐term studies to monitor the medium‐ and long‐term impacts of hydropower projects and to include analyses of vegetation structure (canopy cover, vegetation obstruction and basal forest area), food availability (fruits and insects) and edaphic structure (soil nutrients, granulometry and water table depth) to understand the environmental mechanisms influencing the distribution and abundance of species in landscapes modified by hydroelectric dams (Castro et al, 2021).…”

Benign effects of logging on aerial insectivorous bats in Southeast Asia revealed by remote sensing technologies

“…(2) common species decline in abundance, becoming rare in logged forests; or (3) rare species are locally absent from logged forest. To date, logging-effect studies have found that bat responses to forest change are highly variable between different ensembles of species, particularly dietary guilds (Bicknell et al, 2015;Castro et al, 2021;Castro-Arellano et al, 2009;Clarke et al, 2005;Presley et al, 2008).…”

“…The majority have been undertaken in the American tropics where mist‐netting is more effective at capturing a larger portion of the overall bat community (e.g. Bicknell et al, 2015; Castro et al, 2021; Castro‐Arellano et al, 2009; Clarke et al, 2005). Far fewer studies have been undertaken in the Asian and African tropics as the bat fauna is dominated by aerial insectivorous species (i.e.…”

“…Presley et al (2008) outlined three potential demographic responses for bats in logged forests: (1) common species remain common but decrease in abundance; (2) common species decline in abundance, becoming rare in logged forests; or (3) rare species are locally absent from logged forest. To date, logging‐effect studies have found that bat responses to forest change are highly variable between different ensembles of species, particularly dietary guilds (Bicknell et al, 2015; Castro et al, 2021; Castro‐Arellano et al, 2009; Clarke et al, 2005; Presley et al, 2008). Small, common phytophagous species (i.e.…”

“…The majority have been undertaken in the American tropics where mist-netting is more effective at capturing a larger portion of the overall bat community (e.g. Bicknell et al, 2015;Castro et al, 2021;Castro-Arellano et al, 2009;Clarke et al, 2005).…”