Forest Islands Research Articles

Functional diversity and trait filtering of insectivorous bats on forest islands created by an Amazonian mega dam

Abstract Mega dams in lowland tropical forests often create large archipelagos, leading to biodiversity decay and disruption of ecosystem functioning in remnant habitat islands. We investigated the functional diversity and functional trait filtering of aerial insectivorous bats in both insular forest patches created by a vast ~30‐year‐old hydropower reservoir and the adjacent mainland continuous forest in Central Amazonia. Bats were surveyed using passive bat recorders across 34 forest sites. Based on a set of morphological traits derived for each species recorded, we estimated both the bat functional richness, functional evenness and functional dispersion at each surveyed site. We further assessed the effects of local vegetation, patch and landscape features on patterns of functional diversity. The interaction between functional traits, environmental characteristics, and species distribution was investigated using a combination of RLQ and fourth‐corner analyses. We found that mainland sites retained higher functional richness and lower functional evenness compared to forest islands, indicating a more complete functional assemblage in the mainland. Additionally, species composition was affected by local vegetation structure and forest area, with small isolated islands exhibiting pervasive loss of functional traits. RLQ and fourth‐corner analyses showed that larger understorey foraging species with greater dispersal capacity, constant frequency–frequency modulated calls, and higher frequency of maximum energy were associated with more isolated small islands. Conversely, forest subcanopy species, exhibiting quasi‐constant frequency calls and presenting low dispersal capacity were associated with continuous forests and islands with greater forest area, and were therefore more sensitive to habitat insularization. Our study calls attention to the pervasive impacts induced by large dams on the functional diversity of tropical insectivorous bats. We recommend that future assessments of the effects of habitat fragmentation on mammals should include traits linked to ecosystem services. In designing and licensing new dams, we suggest the creation of extensive protected areas surrounding mainland forests to minimize the detrimental impacts of small isolated islands and safeguard the full complement of key ecological functions provided by insectivorous bats. Read the free Plain Language Summary for this article on the Journal blog.

Holocene history of the lake and forest island ecosystem at and around Lake Seliger, Valdai Hills (East European Plain, Russia)

Holocene history of the lake and forest island ecosystem at and around Lake Seliger, Valdai Hills (East European Plain, Russia)

Begonia amparoi (Begoniaceae, section Baryandra) a new species from Linungaw Twin Islands, Surigao del Sur, Mindanao, Philippines

We describe Begonia amparoi, a new species of Begonia section Baryandra from Linungaw Twin Islands, Mindanao, Philippines. It grows on limestone and has a robust habit, with a thick rhizome and large leaves. Begonia amparoi is currently known only from the type locality in a coastal island forest of Tandag City, Province of Surigao del Sur. Based on IUCN red list criteria, B. amparoi is considered Vulnerable (VU).

Chew-cards can accurately index invasive rat densities in Mariana Island forests

Rats (Rattus spp.) are likely established on 80–90% of the world’s islands and represent one of the most damaging and expensive biological invaders. Effective rat control tools exist but require accurate population density estimates or indices to inform treatment timing and effort and to assess treatment efficacy. Capture-mark-recapture data are frequently used to produce robust density estimates, but collecting these data can be expensive, time-consuming, and labor-intensive. We tested a potentially cheaper and easier alternative, chew-cards, as a count-based (quantitative) index of invasive rat densities in tropical forests in the Mariana Islands, an archipelago in the western North Pacific Ocean. We trialed chew-cards in nine forest grids on two Mariana Islands by comparing the proportion of cards chewed to capture-mark-recapture density estimates and manipulated rat densities to test whether the relationship was retained. Chew-card counts were positively correlated with rat capture-mark-recapture density estimates across a range of rat densities found in the region. Additionally, the correlation between the two sampling methods increased with the number of days chew-cards were deployed. Specifically, when chew-cards were deployed for five nights, a 10% increase in the proportion of cards chewed equated to an estimated increase in rat density of approximately 2.4 individuals per ha (R2 = 0.74). Chew-cards can provide a valid index of rat densities in Mariana Island forests and are a cheaper alternative to capture-mark-recapture sampling when relative differences in density are of primary interest. New cost-effective monitoring tools can enhance our understanding and management of invaded islands while stretching limited resources further than some conventional approaches, thus improving invasive species management on islands.

The Genus Plagiochila (Dumort.) Dumort. (Marchantiophyta) in Madagascar

Plagiochila (Dumort.) Dumort. is one of the largest liverwort genera of Madagascar. A study of the rich Plagiochila holdings from Madagascar kept in the herbaria of Brussels, Eger and Paris leads to the recognition of 22 species, in six sections. One species, P. vandenberghenii Gradst., sp. nov., is new to science and P. bifaria (Sw.) Lindenb., P. macrostachya Lindenb. (synonym: P. granditexta Steph. syn. nov.) and P. simplex (Sw.) Lindenb., all three from the Neotropics, are recorded for the first time from Africa. Madagascar harbors about half of the African Plagiochilas and three species are endemic, P. fracta Pócs, P. sikorae Steph. and P. vandenberghenii Gradst., sp. nov. The high Plagiochila richness of Madagascar is explained by the large tracts on the island of humid tropical montane forest, being the preferred habitat of the genus. East African and Afro-American taxa prevail and four species, P. bifaria, P. macrostachya, P. simplex and P. stricta Lindenb., have a peri-Afro-American range being absent on the African mainland. A key to the Madagassan species of Plagiochila is provided and each species is described and illustrated, with data on types, synonyms, geographical distribution, habitat and differentiating characters.

Forests and Farmers: GIS Analysis of Forest Islands and Large Raised Fields in the Bolivian Amazon

The Llanos de Mojos of the Bolivian Amazon is a domesticated landscape with a long history of management by pre-Columbian communities. This paper uses a landscape approach to interpret the settlement patterns of pre-Columbian raised-field farmers in west central Mojos. The pre-Columbian landscape was reconstructed by mapping the distribution of three types of landscape features: forest islands, raised agricultural fields, and water systems (rivers, streams and wetlands). Previous research has identified four types of patterned clustering or ‘constellations’ of these landscape features in west central Mojos. These constellations and the immediate area of the landscape that surrounds them afforded Mojos farmers a specific set of tasks or activities to take part in as part of harnessing resources from the landscape. The mapping of landscape features and their associated tasks onto the landscape provides insight into the organization of the communities that constructed and managed them. It was found that the landscape of west central Mojos is organized into two distinct regional patterns. In the northern part of the region, evidence of large farming communities is dispersed along the banks of the permanent rivers with networks of landscape features extending off into remote areas of the savanna. In the southern part of the region, evidence for large farming communities is clustered closer together in remote areas of the savanna with networks of landscape features extending back towards the permanent rivers. The two regions are melded together by a transitional zone that implies a type of interaction between the regions rather than a distinct separation.

IDENTIFIKASI PEMANGKU KEPENTINGAN DAN PERANAN DALAM PENGELOLAAN HUTAN LINDUNG GUNUNG SIRIMAU, KOTA AMBON, PROVINSI MALUKU

Protected forest management is the responsibility of all stakeholders related to it. This study aims to identify stakeholders and their roles in protected forest management. The research was conducted in the Mount Sirimau Protection Forest Group, Maluku Province. Collecting data using questionnaires, in-depth interviews, observation and secondary data. Purposive sampling for agencies that have the main tasks and functions and the snow ball method for other stakeholders involved in protected forest management. Data analysis is descriptive qualitative. The results of the identification found the Technical Implementation Unit of the Ambon Island Forest Management Unit and the Lease Islands. Management of protected forests on Ambon Island is intervened by agencies and Technical Implementing Units within the scope of Forestry according to their main duties and functions. Other contributing stakeholders such as Community Social Institutions, Community Organizations, Religious Organizations, Academics, Agencies outside the scope of Forestry such as Public Works and People's Settlements in the Spatial Sector. The role of stakeholders as managers, intervenors, facilitators, participants, evaluators, expert teams, forest resource users and spatial planners.

GENOMIC CHARACTERIZATION OF MULTIDRUG-RESISTANT EXTENDED-SPECTRUM β-LACTAMASE-PRODUCING ESCHERICHIA COLI AND KLEBSIELLA PNEUMONIAE FROM CHIMPANZEES (PAN TROGLODYTES) FROM WILD AND SANCTUARY LOCATIONS IN UGANDA.

Farm and wild animals may serve as reservoirs of antimicrobial-resistant bacteria of human health relevance. We investigated the occurrence and genomic characteristics of extended spectrum β-lactamase (ESBL)-producing bacteria in Ugandan chimpanzees (Pan troglodytes) residing in two environments with or without close contact to humans. The ESBL-producing Escherichia coli and Klebsiella pneumoniae were isolated from fecal material of chimpanzees from Budongo Forest and Ngamba Island Chimpanzee Sanctuary in Uganda and were more commonly isolated from chimpanzees in Ngamba Island Chimpanzee Sanctuary, where animals have close contact with humans. Selected ESBL isolates (E. coli n=9, K. pneumoniae n=7) were analyzed by whole-genome sequencing to determine the presence of resistance genes, as well as sequence type and virulence potential; the blaCTX-M-15 gene was present in all strains. Additionally, the ESBL genes blaSHV-11 and blaSHV-12 were found in strains in the study. All strains were found to be multidrug resistant. The E. coli strains belonged to four sequence types (ST2852, ST215, ST405, and ST315) and the K. pneumoniae strains to two sequence types (ST1540 and ST597). Virulence genes did not indicate that strains were of common E. coli pathotype, but strains with the same sequence types as isolated in the current study have previously been reported from clinical cases in Africa. The findings indicate that chimpanzees in close contact with humans may carry ESBL bacteria at higher frequency than those in the wild, indicating a potential anthropogenic transmission.

Preliminary Study on the Distribution and Diversity of Diptera at Tuba Island Reserve Forest, Langkawi Malaysia

Abstract Insects, the ecologically important organisms, contribute most to the world’s biodiversity. A study on distribution to diversity of order Diptera was conducted in a selected area of Tuba Island Forest Reserve, Langkawi from 17th September to 21st September 2020 using Malaise traps. Three study sites which were forest fringe, middle forest and inner forest were chosen. A total of 5450 individuals of Diptera belonging to 18 families and 27 morphospecies were collected in this study. Diptera samples were highly abundant in the forest fringe with Mycetophilidae as the most abundant family recorded, while the least abundant family was Drosophilidae. The Shannon-Weiner Diversity Index (H’) showed that the forest fringe had the highest diversity value (H’=2.05), followed by the inner forest (H’=0.67) and middle forest (H’=0.45). The highest Evenness Index (E’) value was recorded from the inner forest with E’=0.66 while the highest value for Margalef Richness Index (R’) was from the forest fringe which was 1.91. The Kruskal-Wallis H test conducted indicates that there was a significant difference in the distribution of Dipteran across the three locations of the forest with P<0.05. Overall, this study suggested that the diversity of order Diptera was higher in the forest fringe compared to the middle and the inner forest. This study is important as it is helpful for future study of Diptera species in Tuba Island as well as for conservation measures in the island ecosystem.

Assessing local knowledge on the diversity and abundance of bushmeat species and hunting pressure in the fragmented forest islands of southern Benin (Dahomey Gap)

AbstractIllegal hunting of wildlife is one of the major issues in tropical ecosystems, especially when it occurs in highly degraded habitats with forest cover fragmentation. In this study, we assessed the impact of bushmeat hunting in a large forest patch (the Lama Natural Forest; LNF) and 11 nearby forest islands, using Traditional Ecological Knowledge from 240 interviewees across 16 villages. Thirty‐five species belonging to nine orders of mammals, birds and reptiles were mentioned by local communities. Rodentia were significantly more observed in the forest islands, whereas medium‐sized mammals belonging to Carnivora, Primates, Artiodactyla, Pholidota and Hyracoida were found predominantly in LNF. Approximately 57% of the species were reported to be rare in the forest islands, whereas c. 77% were listed as abundant in LNF, confirming the role of LNF as a refuge for forest species targeted by the bushmeat trade. Generalised linear models indicated that species sighting frequencies were positively correlated with perimeters of forest patches. We found hunting pressure to be greater in forest islands in the vicinity of LNF than those further away. Our results suggest that long‐term conservation of wildlife in southern Benin may require a ‘mainland‐islands’ approach including both LNF and its surrounding forest islands.

Soil aggregate stability of forest islands and adjacent ecosystems in West Africa

In the mesic savannas of West Africa, areas around villages of relatively tall and dense forest vegetation are often found. These ‘forest islands’ are presumably the direct outcome of human activity. To better understand these patches with relatively luxuriant vegetation, our study focused on how they influence soil aggregate stability- a key indicator of soil resilience to degradation through erosion. We compared the proportion of stable soil aggregates of the forest islands with nearby croplands and natural savanna vegetation across a precipitation transect in West Africa for which mean annual precipitation at the study sites ranges from 0.80 to 1.27 m a−1. Soil samples were taken from 0–5 cm and 5–10 cm depths and stability of soil aggregate groups with diameters: > 500 μm, 500–250 μm and 250–53 μm (viz. “macroaggregates”, “mesoaggregates” and “microaggregates” respectively) determined using the wet sieving method. The results showed significantly (p < 0.05) higher proportion of stable soil meso- and macro-aggregates in forest islands and natural savanna than in agricultural soils. Although there was no effect of land-use type on microaggregate stability, there was a strong tendency for the stable microaggregates across all land use types to increase with increasing precipitation. Soil organic carbon and iron oxides contents were the most important factors influencing meso and macro-aggregate stability in the West African ecosystems. We conclude that formation of stable soil microaggregates in the West African ecosystems was climate or precipitation driven whereas the more labile and larger-size groups of meso-and macro- aggregates was land-use driven. The study provides first insights in soil quality processes in a poorly studied but unique phenomenon of man-made forest islands in West Africa.

Taxonomic, structural diversity and carbon stocks in a gradient of island forests

Assessment of forest ecosystems and their services is seen as a key action for the advancement of biodiversity objectives, and to inform the development and implementation of related policies and planning. The Azorean forest is important for timber production, the protection of soil and water resources, and for its recreational and aesthetic value. However, its role in carbon accumulation has not been fully addressed. We assessed plant diversity, forest structure and carbon stocks in a gradient of three forest types (Natural Forest-NF; Exotic Woodland-EW and Production Forest-PF) in three of the Azores islands. We used biodiversity indices and found that NF harbored the highest plant diversity levels and PF the lowest. Diversity levels were lower for structural than for taxonomic data, particularly for PF. The highest tree carbon stock was found at EW in one of the islands, while PF consistently exhibited relatively high tree carbon stocks in the three islands. The largest soil carbon stocks were found at EW, while leaf litter carbon stocks were higher at PF. We concluded that NF play a fundamental role as plant diversity hotspots but have lower relevance as carbon stocks what might be associated with montane environmental conditions. PFs provide economic assets and act as carbon sinks, while EWs play a major role as carbon sinks in soil, but also at tree level in the oldest forests.

Effects of forest degradation on Amazonian ferns in a land‐bridge island system as revealed by non‐specialist inventories

Abstract Tropical forests have been rapidly deforested and degradation worldwide has outpaced biodiversity field sampling. No study to date has assessed the effects of insular habitats induced by hydroelectric dams on Amazonian understory plants. Fern community responses to anthropogenic effects on tropical forest islands can be revealed at a faster pace by using simple and cheap, yet informative, protocols that could be applied by non‐specialists. This study seeks to both understand the drivers of fern and lycophytes assemblages on forest islands and investigate the relative costs and effectiveness of a simplified sampling protocol that can be applied by non‐specialists. Fern species were sampled by a non‐specialist who photographed all ferns and lycophytes within seventeen 0.25‐ha plots on 10 forest islands at the lake of Balbina Hydroelectric dam, central Amazonia. Sampling was carried out opportunistically during a field expedition planned to conduct tree inventories. As predictors, we used locally measured or GIS‐derived descriptors of plot and landscape conditions. We used multivariate and linear models to further assess the influence of predictors on patterns of species richness and composition of ferns assemblages. A total of 286 photographed individual ferns or lycophytes represented at least 23 species and 14 genera. The average number of taxa per plot was 6.1 in the islands and 14.3 in the mainland. The species pool found on islands was a nested subset of the mainland fern community. Species richness was positively related to island size and negatively related to isolation and fire severity. Area, isolation and fire severity also significantly explained variation in community composition. The relative cost of the picture‐based fern protocol applied was very modest (only 4% of the total expedition budget), even compared to the typically low cost of alternative field campaigns. We conclude that fern community structure in this forest archipelago was primarily driven by island size, isolation and fire disturbance. Moreover, we show that a simple sampling protocol carried out by a non‐specialist can lead to inexpensive and highly reliable ecological data. This opens an avenue for crowdsourcing ecological fern data collections using a citizen science approach.

Preliminary study on hymenopteran distribution and abundance from island ecosystem of Tuba Island Forest Reserve, Langkawi

The study was performed to determine the diversity and distribution of Hymenoptera across the environmental gradient ranging from fringe forest, mid forest to inner forest. The study was conducted in a selected area of Tuba Island Forest Reserve from 17th to 21st September 2020 using Malaise trap, an insect capturing trap. During this study, a total of 133 individuals of Hymenoptera were sampled from 12 families and 27 morphospecies. Hymenoptera was most abundantly found in the forest fringe with 64 individuals (11 families, 25 morphospecies) and least abundant in the inner forest with 26 individuals (7 families, 8 morphospecies). The top three highest number of individuals recorded were Formicidae (43 individuals), Braconidae (28 individuals) and Ichneumonidae with 27 individuals. Shannon-Weiner Diversity Index (H') showed that the forest fringe had the highest diversity value with H'=1.80 while the lowest was recorded in the mid forest with H'=1.43. The Evenness Index (E’) was highest at mid forest (E’=0.81) and the Margalef Richness Index (R’) value recorded the highest at forest fringe indicating a high species richness with R’=2.40. Kruskal-Wallis test reveals that the distribution of Hymenopterans from the forest fringe to the inner forest did not differ significantly with P&gt;0.05. High similarities in microclimate variables (monsoon season, temperature, humidity, and light intensity), resources availability, forest features, hiding places, and the presence of predators are among the factors influencing the homogeneity of the composition and abundance of Hymenoptera in Tuba Island. This study is the first checklist of Hymenoptera in Tuba Island and can be utilised as a baseline dataset for further ecological research at Tuba Island.&#x0D;

Spatiotemporal Distribution of Herbivorous Insects Along Always-Green Mountaintop Forest Islands

Insects make up the bulk of terrestrial diversity and about half of insect species are herbivores that have direct relationships with their host plants and are the basis of the entire food chain, on which wildlife and humanity depend. Some herbivorous insect traits, such as their spatio-temporal distribution, are especially relevant in the current scenario of global changes, which are more pronounced in high elevation areas, helping to improve the effectiveness of conservation actions. Here we evaluated the influence that different spatiotemporal scales have on three free-feeding herbivorous insect guilds (fluid-feeding, leaf-chewing, and xylophagous insects) in montane forest islands immersed in a grassland-dominated matrix (campo rupestre). We assessed whether species turnover or nestedness was the main component determining both spatial and temporal species composition variation (β-diversity) of the herbivorous insect community. We also checked the temporal effect on herbivorous insect guilds composition between vertical strata. We sampled herbivorous insects during two summers and two winters in 14 forest islands of different sizes and shapes in a natural mountainous fragment located in southeastern Brazil. A total of 6597 herbivorous insects representing 557 morphospecies were sampled, 290 of which were fluid-feeding, 147 leaf-chewing and 120 xylophagous insects. We found a main contribution of time scale in the organization of the herbivorous insect composition sampled in this study, mainly by turnover, with small differences among guilds. Additionally, we could see that climate determined the local variation of species, corroborating that we have a highly variable always-green system over space and time where the understory community varies less in comparison to the canopy community. Our findings suggest that long-term ecological research on herbivorous community structure in relation to climatic variation is a key element for future investigations, which can be decisive for the conservation of herbivorous insect communities. We also suggest that the effects of anthropogenic pressures must be monitored in this system, since these forest islands may serve as warming refuges in a fragmented landscape holding an invaluable diversity of species that, without these old-growth forest reservoirs, would be doomed to disappear.

Size-related seed use by rodents on early recruitment of Quercus serrata in a subtropical island forest

Rodents are ubiquitous seed predators in nature and their size-related seed choice plays an important role in the plant’s community structure. However, to understand how size-related seed predation by rodents affects plant recruitment, it is fundamental to predict seed and seedling response to rodent predation. We assessed the interactive effects between seed size and rodent exclusion on seed germination and early seedling survival of Quercus serrata in 10 subtropical forested islands in Thousand Island Lake, China. We found that rodent exclusion significantly improved the proportion of seed germination but not for early seedling survival. The proportion of seed germination in rodent-accessed plots was lower than rodent-exclosure plots and such reduction was strengthened by seed size. The proportion of early seedling survival was similar in both treatments and both increased with seed size. Our study found a significant size-related seed choice by rodents at the seed germination stage and showed that seeds would experience conflicting selective pressures across life stages in the early recruitment. Our findings highlight that size-dependent seed use by rodents is a key biotic factor to limit the oak early recruitment.

Fragmentation and Connectivity of Island Forests in Agricultural Mediterranean Environments: A Comparative Study between the Guadalquivir Valley (Spain) and the Apulia Region (Italy)

Habitat loss and fragmentation are considered some the main threats to biodiversity. Original forests have suffered an accentuated fragmentation and agricultural homogenization, leaving only some areas of natural vegetation, relegated to strongly anthropized disconnected patches (island forests, IFs) in a hostile matrix. These patches of original vegetation could be the key for the design and management of ecological corridors to promote species migration, an essential strategy for meeting the consequences of Global Change. This study proposes a comparative analysis of the fragmentation and connectivity of IFs of Quercus in two typically Mediterranean areas of predominantly agricultural use: the Guadalquivir valley (Spain) and the Apulia region (Italy). A retrospective comparison is also carried out in the Guadalquivir valley. The aim is to develop an objective new methodology to locate the patches of most interest using quantitative and qualitative data. Reference cartography of current island forests of Quercus species was developed from several digital sources and validated with orthoimages and field observations. Fragmentation analysis was based on graph structures using the software Conefor 2.6, a reliable tool for assessment of the role of patches in the landscape. Area and distance were used as node and connector values. Dispersion distance was established as 500 m, based on the maximum dispersion of acorns. Results indicate that the Guadalquivir valley has suffered an intensive fragmentation in recent decades. Both the Guadalquivir and Apulia regions host some IFs with the relevant potential to contribute as core habitats in the creation of connections to other natural protected sites. Many residual IFs in the landscape could contribute as stepping stones in the design and management of ecological corridors. Our methodology highlights the value of IFs to develop assessment strategies using homogenized available digital cartography and common criteria for the dispersion distances in graph theory analysis. The application of this new methodology could help in the management of protected sites using highly fragmented areas to allow the species movement through inhospitable landscapes in a unique opportunity to connect the different protected areas.

Beyond order, beyond the human

Beyond order, beyond the human

Spatiotemporal effects on dung beetle activities in island forests-home garden matrix in a tropical village landscape

Insects in seasonal tropics experience a wide range of temperatures along seasons, habitats, and a day. Therefore, the thermal tolerance of the insects can be a major driver for their habitat preference, temporal patterns of activity, and formation of communities. We examined the dung beetle communities of eleven pairs of neighboring open (home gardens) and closed habitats (sacred groves) during dry and wet seasons and diel periods (day and night) to understand the dung beetle activities along a spatiotemporal gradient constituted by the sacred groves—home garden matrix on a tropical village landscape. We tested the following hypotheses: (i) closed habitats have greater activities of dung beetles over open habitats; (ii) the diurnal communities of dung beetles are different from the nocturnal communities; and (iii) the diurnal-nocturnal activities of dung beetles could be predicted by the habitat and season. We considered abundance, richness, total biomass, and Shannon diversity of overall beetles, abundance of different functional groups, and species composition in communities as the quantitative measures in the predictive statistical models. In total, 2727 dung beetles belonging to 38 species, ten genera, and three functional groups were collected. The open habitat supported more number of dung beetles (N = 2318) than the closed habitat (N = 409). The diurnal communities were different from nocturnal communities, particularly in open habitat, where the temperature was different between day and night. The dominant species of the diurnal communities of open habitat hardly used the closed habitat in any context including dry–wet seasons, but the nocturnal communities of the open habitat were closer to the communities of closed habitat. The diel period and habitat predicted the abundance activity of functional groups; season was a poor predictor of dung beetle activities. Given that the species composition has turned over across habitats, and the closed habitat supported remarkably lesser number of beetles than the open habitats, the closed habitat is unlikely to be a thermal refuge for the open habitat species in village landscapes that have island forests, such as sacred groves, and home gardens form a matrix.

Forest area predicts all dimensions of small mammal and lizard diversity in Amazonian insular forest fragments

ContextAlthough hydropower development is one of the primary drivers of habitat loss and insular fragmentation, its impacts on species identity and their functional and phylogenetic roles have often been overlooked.ObjectivesHere we use an integrative approach, considering taxonomic, functional and phylogenetic dimensions at multiple scales, to understand the processes underlying species (dis)assembly of two taxa exhibiting relatively low dispersal ability: small mammals and lizards.MethodsWe surveyed 26 islands within the Balbina Hydroelectric Reservoir, and adjacent continuous forest, in Central Amazonia. Each dimension of diversity was related to spatial and habitat variables. We also examined functional composition using community-weighted mean trait values, and community redundancy using functional uniqueness. β-diversity was partitioned into their richness (βrich) and replacement (βrepl) components.ResultsFunctional and phylogenetic α-diversities of both taxa mirrored the taxonomic dimension, all of which increased with forest area. Individual small mammal (body mass and matrix tolerance), and lizard traits (body length, heliothermic mode and habitat type) were also predicted by forest area. For both groups, functional uniqueness decreased with forest area, and all dimensions of β-diversity were predominantly partitioned in βrich.ConclusionsThe environmental filter created by forest area resulted in the low conservation value associated with small forest islands, only occupied by a small set of species comprised by generalist lizards and matrix-tolerant small mammals. On the other side, large forest sites ensured ecosystem resilience to disturbance. To maintain ecosystem integrity, creating myriad small islands over large expanses of floodwaters should be avoided in future hydropower development.