Biology subjects

Palmeirim, A. F.

Publications and source records attributed to Palmeirim, A. F..

7 recordsLinked to original sources

bioRxiv2025

Habitat use and diel activity of insectivorous bats across land-use types on an Afrotropical oceanic island

Tropical island biodiversity is declining at alarming rates. Yet, understanding how species are coping with such disturbance is largely limited for afro-tropical islands. Here we examined habitat use and diel activity of insectivorous bats across different land-use types covering the endemic-rich Principe Island, Central West Africa. We acoustically surveyed insectivorous bats across 48 sites throughout old-growth forests, secondary re-growth forests, cocoa shaded plantations, and horticultures. Based on 17,527 bat-passes, we were able to record all four insectivorous bat species known to occur on Principe, including the recently described Pseudoromicia principis, the most frequently recorded species. Taphozous mauritianus, a data deficient open-space forager, was the least recorded species. Species activity was lowest in old-growth forests, as well as the activity of the edge-forager P. principis. The activity of the open-space forager Mops pumilus was lowest in forest habitats, whereas Hipposideros ruber, a forest forager, was restricted to these habitats. Diel activity patterns of M. pumilus varied between forests and non-forest habitats, whereas those of P. principis remained similar. Interspecific activity overlap decreased towards more altered land-use types. Our findings emphasize that conserving the remaining forests, along with the current mosaic of land-uses, is needed to maintain Principes complete insectivorous bat assemblages.

ecology↗

bioRxiv2025

Forest conversion to cashew orchards delays the diel activity of diurnal mammals in West Africa

Land-use change is the main driver of biodiversity loss worldwide. However, less is known about how species adapt their behavior to persist in human-altered habitats. We addressed this gap by examining mammal responses in terms of habitat use and diel activity patterns to forest conversion into cashew orchards in West Africa. We surveyed mammals using camera-trapping in 12 forest sites and 12 cashew orchards in the Cantanhez National Park in southwest Guinea-Bissau, West Africa. We grouped mammals into (1) diurnal and cathemeral and (2) nocturnal species according to their diel activity periods and assessed their use and diel activity between habitat types. Based on 709 trap-days, we obtained 842 records of 12 diurnal or cathemeral species (18.3% of the records) and 13 nocturnal species (81.7%). Mammal habitat use was similar between forests and cashew orchards for both diurnal/cathemeral and nocturnal species. However, the peak of diurnal/cathemeral species shifted from the morning period ([~]11h00) in the forests to the afternoon period in the cashew orchards ([~]16h30), resulting in little overlap in activity of diurnal/cathemeral species between habitat types. No differences were observed in the diel activity of nocturnal mammals. Although mammals can make use of altered habitats, diurnal species are able to delay their activity, probably to avoid direct contact with humans. Our study highlights the ability of species in adapting their behaviour to persist in newly human-modified landscapes in the tropics.

ecology↗

bioRxiv2025

Mammal responses to habitat degradation induced by cashew expansion in West Africa

Tropical landscapes are perishing due to high rates of land-use change. In West Africa, Guinea-Bissau lost 77% of its closed-canopy forest over the last 25 years, mostly to the expansion of cashew monoculture. To date, understanding how species cope with such changes remains a conservation priority for the region. Here we examine mammal species composition, richness, and abundance, in addition to trophic-guild abundance across closed-canopy sub-humid forests and cashews orchards in the Cantanhez National Park, southwest Guinea-Bissau. Mammals were surveyed using one camera trap at each of the 24 sites, half in forest and half in cashew orchards, and their local and landscape-scale variables were measured. Based on 709 trap-nights, we collected 842 records from 25 mammal species. Local habitat structure--including canopy openness, floor obstruction, density of both lianas, palms and trees, tree species richness and height--sharply contrasted between forests and cashew orchards. As expected, mammal species composition differed between forests and cashew orchards, and the estimated, but not the observed, species richness declined towards cashew-like habitats. Although overall mammal abundance remained unaffected by the variables considered, carnivores were more abundant in cashew-like habitats, whereas insectivores and herbivores were more abundant in forest-like habitats. Human activity and distance to forest did not affect the response variables considered. Forest conversion into cashew orchards negatively affects mammals by profoundly changing the local habitat structure. Guild-level responses further unveiled specificity in their vulnerability to this form of land-use change, alerting for a potential disruption in the ecosystem functioning. We emphasize the need for policies that limit monoculture expansion, while safeguarding the remaining forests, thus maximising biodiversity persistence across the Afrotropics.

ecology↗

bioRxiv2024

Amphibian and reptile dataset across different land-use types in Guinea-Bissau, West Africa

West Africa is exceptionally biodiverse, yet its wildlife remains largely understudied despite the rapid and ongoing land-use changes. Large swaths of Guinea-Bissaus landscape were historically characterized by native forest-savanna mosaics. However, key areas of savannah habitats have been converted to rice agroecosystems, and forests are being transformed into cashew monocultures at unprecedented rates. Amphibians and reptiles (Testudines and Squamata) comprise some of the most threatened species by human-induced habitat change, and yet are not as studied as other vertebrate terrestrial taxa. Here, we provide two comprehensive datasets on amphibians and reptiles (classes Testudines and Squamata) from northern Guinea-Bissau: (1) a standardized survey dataset (encompassing sampling events and occurrences) in forest fragments, cashew orchards, and rice paddies, and (2) an opportunistic dataset reporting occurrences across the entire study area. Standardized surveys were carried across 21 sampling sites, seven in each habitat type, while opportunistic surveys include all other records. For standardized surveys, a total of 703 amphibian and 265 reptile (class Squamata) encounters are reported, corresponding to nine and 13 taxa, respectively. Opportunistically, we report 62 amphibian and 93 reptile encounters, corresponding to 10 amphibian taxa, 25 Squamata taxa, and two turtles (class Testudines). New informationBased on 126 sampling hours of both diurnal and nocturnal standardized surveys, in addition to opportunistic surveys, these datasets comprise the first overview for amphibians and reptiles in mainland Guinea-Bissau across two seasons and different habitat types. Each of the 968 standardized and 155 opportunistic occurrences corresponds to a genus or species and is accompanied by geographic coordinates, a timestamp, and, for standardized data, the land-use type. The datasets fill the distribution gaps in Guinea-Bissau of at least three species, including the frog Hildebrandtia ornata, the skink Trachylepis keroanensis and the snake Dendroaspis polylepis - and includes the rediscovery of the lizard Latastia ornata in Guinea-Bissau. Before this work, the L. ornata was only known from the 1938 holotype in Bafata (ca. 60 km away from the study area) and, in 2023, from Guinea-Conakry (ca. 700 km away from type specimen location).

ecology↗

bioRxiv2024

Unveiling how herpetofauna cope with land-use changes--insights from forest-cashew-rice landscapes in West Africa

Agricultural-induced land-use change comprises a key driver of biodiversity loss across tropical forests. Guinea-Bissau, in West Africa, was formerly occupied by native forest-savanna mosaics. While savannas have long gave place to traditional rice agroecosystems, forests are now being transformed into cashew monocultures at unprecedented rates. The ecological impact of such rapid change is largely unknown. Here, we examined how rarefied species richness, abundance, and composition of amphibians and reptiles varied across forest remnants, cashew orchards and rice paddies in northern Guinea-Bissau. To do so, visual encounter surveys were carried across 21 sampling sites, seven in each habitat type. A total of 703 amphibian and 266 reptile encounters was recorded from nine and 14 taxa, respectively. The results show class-specific responses to habitat type. Amphibian diversity in forest remnants and cashew orchards remained similar, but rice paddies harboured higher abundance and distinct composition compared to forest remnants. Reptile abundance was highest in cashew orchards, which comprised a distinct species composition, when compared to forest remnants. Rice paddies sustained lower reptile richness and abundance. Overall, our results do not support the expected detrimental impacts of cashew expansion, which might be due to the still high heterogeneity of habitat types within the landscape. Rice paddies proved particularly important for amphibians, and for open-habitat reptiles, boosting the landscape-scale species diversity. In face of the eminent habitat conversion, maintaining heterogeneous landscapes, including the persistence of both forest remnants and rice paddies, is critical to minimize biodiversity loss in West Africa.

ecology↗

bioRxiv2024

Indirect effects of habitat amount mediated by habitat configuration determine bat diversity at the landscape-scale in Peninsular Malaysia

The impacts of fragmentation are often overlooked in landscape studies investigating how habitat loss impacts biodiversity, despite the casual relationship linking both processes. As habitat loss is the primary cause of fragmentation, understanding the inter-related effects of these twin processes on biodiversity is key to minimise biodiversity loss. Here we assess how habitat amount and configuration influence insectivorous bat assemblages, considering both the direct effects of these processes, as well as the indirect effects of habitat amount mediated through configuration. Bats were acoustically surveyed along independent gradients of habitat amount (forest cover) and configuration (number of patches and edge density) across 28 insular landscapes embedded within a Malaysian hydroelectric reservoir. Using Structural Equation Modelling, the direct and indirect effects of habitat amount were examined on bat sonotype richness, total, and guild-specific activity (forest, edge and open-space foragers). Forest cover had a direct and positive effect on sonotype richness and forest forager activity. The quadratic relationship linking edge density and forest cover was strong and overall positive, but while below 30% of forest cover, increasingly forested landscapes had increasingly high edge densities, the opposite pattern was observed in more forested landscapes. On the other hand, increasingly forested landscapes consistently harboured less patches. Owing to the overall low habitat amount in our landscapes and negative edge effects, the indirect effects of forest cover (mediated through edge density) were therefore negative on sonotype richness, outweighing any positive direct effect. The number of patches had little effect on the bat assemblage, except on total activity which was higher in landscapes harbouring more forest patches. As a result, negative indirect effects of forest cover mediated through number of patches were only observed on total activity. Our results highlight that, in natural settings, habitat amount can hardly be altered without influencing habitat configuration, thereby preventing any independent management of these threats. Minimising habitat loss is therefore essential to balance the associated prevailing negative effects of fragmentation on insectivorous bats across tropical forests.

ecology↗

bioRxiv2023

Foraging guild modulates insectivorous bat responses to habitat loss and insular fragmentation in peninsular Malaysia

Despite mounting evidence on the ecological impacts of damming for biodiversity, little is known regarding its consequences in the hyper-diverse Southeast Asian tropical forests. Here we assess the effects of habitat loss and fragmentation on the diversity and activity of insectivorous bats within the hydroelectric Kenyir Lake in peninsular Malaysia. We surveyed bat assemblages on 26 islands and two mainland continuous forest sites using passive acoustic monitoring. Echolocation calls were classified into sonotypes, each corresponding to either one or multiple species, and grouped into foraging guilds. We then examined bat overall assemblage (sonotype richness, activity, and composition), guild- and sonotype-specific activity. From 9360 hours of recordings, we identified 16 bat sonotypes, including 10 forest (2854 bat passes), three edge (13 703) and three open-space foragers (3651). Sonotype richness increased towards denser forest structures (higher Normalized Difference Vegetation Index - NDVI), while species composition varied across the gradient of forest area. Forest foragers were positively affected by NDVI and negatively affected by distance to the closest neighbour, whereas edge foragers activity increased in smaller islands. Of the six sonotypes analysed, the activity of one forest sonotype increased with forest area, while that of one edge sonotype decreased. Ensuring habitat quality within insular forest remnants, in addition to their functional connectivity, maximises bat diversity, including the persistence of forest foraging species. Future hydropower development should therefore avoid the creation of a myriad of small, isolated, and habitat-degraded islands further characterised by altered levels of bat diversity and guild-level activity. HighlightsO_LIWe assessed the diversity of insectivorous bats in dam-induced islands in Malaysia C_LIO_LISpecies persistence was modulated by island size and habitat quality C_LIO_LIForest foragers were negatively affected by island isolation and degradation C_LIO_LIEdge foragers benefited from fragmentation, increasing in activity on smaller islands C_LIO_LIBy creating multiple small, isolated, degraded islands, damming erodes bat diversity C_LI

ecology↗