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Most biological invasion literature—including syntheses and meta-analyses and the resulting theory—is reported from temperate regions, drawing only minimally from the tropics except for some island systems. The lack of attention to invasions in the tropics results from and reinforces the assumption that tropical ecosystems, and especially the continental tropics, are more resistant to invasions. We have critically assessed biological invasions in the tropics and compared them with temperate regions, finding relatively weak evidence that tropical and temperate regions differ in their invasibility and in the traits that determine invader success and impacts. Propagule pressure and the traits that promote adaptation to disturbances (e.g., high fecundity or fast growth rates) are generally favorable to invasions in both tropical and temperate regions. We emphasize the urgent need for greater investment and regional cooperation in the study, prevention, and management of biological invasions in the tropics.

Current policy is driving renewed impetus to restore forests to return ecological function, protect species, sequester carbon and secure livelihoods. Here we assess the contribution of tree planting to ecosystem restoration in tropical and sub-tropical Asia; we synthesize evidence on mortality and growth of planted trees at 176 sites and assess structural and biodiversity recovery of co-located actively restored and naturally regenerating forest plots. Mean mortality of planted trees was 18% 1 year after planting, increasing to 44% after 5 years. Mortality varied strongly by site and was typically ca 20% higher in open areas than degraded forest, with height at planting positively affecting survival. Size-standardized growth rates were negatively related to species-level wood density in degraded forest and plantations enrichment settings. Based on community-level data from 11 landscapes, active restoration resulted in faster accumulation of tree basal area and structural properties were closer to old-growth reference sites, relative to natural regeneration, but tree species richness did not differ. High variability in outcomes across sites indicates that planting for restoration is potentially rewarding but risky and context-dependent. Restoration projects must prepare for and manage commonly occurring challenges and align with efforts to protect and reconnect remaining forest areas. The abstract of this article is available in Bahasa Indonesia in the electronic supplementary material. This article is part of the theme issue 'Understanding forest landscape restoration: reinforcing scientific foundations for the UN Decade on Ecosystem Restoration'., Philosophical Transactions of the Royal Society B: Biological Sciences, 378 (1867), ISSN:0962-8436, ISSN:1471-2970, ISSN:0080-4622

How people relate to biodiversity and whether they are supportive of conservation programs and policies has implications on global and local biodiversity conservation efforts. Nature experiences in childhood has been shown to be strongly correlated to positive attitudes towards nature and wildlife in adulthood. In this study, we examined wildlife experience, attitudes and willingness to coexist with 26 vertebrates and invertebrates amongst residents in a highly urbanized tropical city, Singapore. A total of 1004 respondents were surveyed and their childhood nature experience and various socioeconomic variables were obtained. The animals were grouped by their likeability and preferred habitat from the respondents' answers. Three main groups of animals were discerned - unfavorable animals, mammals, and favorable animals. Singapore residents generally had high direct experiences of animals that are common in urban settings, for both favorable and unfavorable animals, such as butterflies, dragonflies, crows and bees, but low direct experiences of forest-dependent wildlife. Animals that were well-liked and acceptable near homes include the common urban ones and some forest-dependent ones, while animals that were disliked included stinging insects (bees and hornets) and reptiles (snakes and water monitors). Structured equation modelling showed that both childhood nature experience and wildlife experience had strong effects on wildlife likeability and habitat preference. The apparent mismatch between greening policies and people's willingness to coexist with wildlife may be problematic as urban development further encroaches on forest habitats, and this study highlights the importance of preserving forest habitats so that young children and adults have opportunities to be exposed to them.The online version contains supplementary material available at 10.1007/s11252-022-01280-1.

Species radiations have long fascinated biologists, but the contribution of adaptation to observed diversity and speciation is still an open question. Here, we explore this question using the clove genus, Syzygium, the world’s largest genus of tree species comprising approximately 1200 species. We dissect Syzygium diversity through shotgun sequencing of 182 distinct species and 58 additional as-yet unidentified taxa, and assess their genetic diversity against a chromosome-level reference genome of the sea apple, Syzygium grande. We show that Syzygium grande shares a whole genome duplication (WGD) event with other Myrtales. Genomic analyses confirm that Syzygium originated in Sahul (Australia-New Guinea), and later diversified eastward to the Hawaiian Islands and westward in multiple independent migration events. The migrations were associated with bursts of speciation events, visible by poorly resolved branches on phylogenies and networks, some of which were likely confounded by incomplete lineage sorting. Clinal genomic variation in some sublineages follows phylogenetic progression, which coupled with sympatric occurrences of distantly related species suggests that both geographic and ecological speciation have been important in the diversification of Syzygium. Together, these results point to a mixture of both neutral and adaptive drivers having contributed to the radiation of the genus.

Low vegetation cover in cities result in urbanites generally receiving less exposure to nature compared to people living in rural areas. Consequently, childhood experiences in a city tend to be less nature-oriented, leading to a detachment from nature in adulthood. However, some cities may have pockets of green spaces that harbour wildlife, and interactions between people and the wildlife around them may have an influence on wildlife conservation attitudes. To investigate the relationships between childhood nature experience and attitudes towards wildlife, we carried out a survey on 1004 Singapore residents about their attitudes and tolerance towards three types of wildlife commonly encountered in Singapore. Structured equation models (SEMs) were used to model the relationship between childhood experience, attitudes towards wildlife, and tolerance levels in three scenarios of increasing damage severity to humans. We found that most respondents had low childhood nature experience, and had neutral/negative attitudes towards all three types of wildlife. Childhood experience was the strongest predictor of wildlife attitude, which varied with age, gender, education level and type of wildlife. Attitude towards wildlife was the strongest predictor of tolerance in all scenarios, while tolerance decreased with increasing severity of damage. Our findings point to the importance of childhood nature experience in shaping adult perceptions of wildlife and their willingness to coexist with wildlife. Given that Singapore is continually developing on forested land for residential and commercial purposes, wildlife encounters are predicted to increase in the future. With proper planning and education, residents near wildlife habitats can learn to live with and appreciate the wildlife around them. Accepted version

A considerable extent of interspecific hybridization among dominant canopy dipterocarp species was recently found in a tropical rain forest fragment in Singapore. However, information about the fertility of the hybrids and the growth of their successive hybrids remains limited. We studied the flowering phenology of four dipterocarp species in the genus Shorea (S. curtisii, S. leprosula, S. parvifolia, and S. macroptera) and two hybrids (S. curtisii × S. leprosula and S. leprosula × S. parvifolia) and studied the performances of seedlings reproduced from them. We observed that S. macroptera bloomed first, without overlap with congeneric species, followed by the other Shorea species and the two first filial (F1) hybrids. S. curtisii and S. leprosula, the species forming hybrids are most likely to succeed in this forest, completely overlapped with their hybrids. Fruits collected from the hybrids were viable, and these hybrid seedlings showed greater survival and a higher growth rate than those from pure species under greenhouse conditions. They included various cross types such as a backcross with each parent species. These results may imply that successive hybrids and introgression spontaneously occur among Shorea species. It may be important to consider the risk of hybridization for the management of tropical forests, particularly in degraded tropical rainforests where mechanisms of ecological isolation between closely related species might be altered. Accepted version

Background: Fragmentation can fundamentally alter the structure of tropical forests. However, the impacts of fragmentation may vary significantly among regions and lead to different outcomes.Aims: We examined the structure, composition and dynamics of a forest fragment in Singapore to investigate reasons for the apparent resilience of this forest to long-term isolation.Methods: We conducted 5 censuses of 12,688 trees ≥1-cm dbh in a 2-ha plot on the edge of the fragment between 1993 and 2012.Results: Stem density and basal area were not significantly different between 1993 and 2012 and were typical of other south-east Asian forests. However, there were short-term decreases in both variables after droughts in 1997 and 2009, both followed by recovery. Total mortality rate over the 19 years was 3.3% year−1, considerably higher than other tropical forests in Asia, but it was balanced by high recruitment. The 10 most abundant species were primary forest species, pioneer species comprised

Based on collections focusing on Graphidaceae made in 2012 at Bukit Timah Nature Reserve (BTNR) in Singapore, seven new species are described: Astrochapsa sipmanii, differing from A. astroidea in the olive-brown thallus and thick and coarse apothecial pruina; Fissurina duplomarginata, differing from F. insidiosa by the double margin of the lirellae and the more greenish, rough thallus; Graphis bukittimaensis, differing from G. phaeospora in the erumpent lirellae with lateral thalline margin and the consistently 1-spored asci; G. singaporensis, differing from G. novopalmicola in the much smaller ascospores and in the immersed, densely branched lirellae with thin lateral thalline margin; Ocellularia subudupiensis, differing from O. udupiensis in the presence of three unknown secondary substances and in the comparatively rough thallus surface; O. gueidaniana, characterized by small, transversely septate, hyaline ascospores, prominent, carbonized but ecolumellate apothecia, and two unknown chemical substances resembling metabolites in the stictic acid chemosyndrome; and O. rivasplatana, differing from O. exigua in the larger, broad-pored apothecia with black-rimmed margin and filled with a black-topped columella. Nineteen species are recognized as new records for Singapore. The substantial diversity of Graphidaceae in this reserve suggests that many more taxa are awaiting discovery, even in such a highly urbanized location.

Understanding the structure and diversity of secondary tropical forests is important as they constitute an increasing proportion of tropical landscapes. However, few studies have investigated the long-term recovery of tropical forests following agricultural abandonment. We compared the physical structure and tree species composition of a 56-year-old 2-ha secondary forest plot with an adjacent 2-ha primary forest in Singapore. All trees ⩾ 1 cm in diameter were surveyed. We found that after 56 years of recovery, the secondary forest remains floristically and structurally distinct from the adjacent primary forest. The secondary forest plot had 30% of the stem density, 58% of basal area, 26% of species richness and 59% of the Shannon diversity as compared to the primary forest plot. Nonmetric multidimensional scaling analysis and partial Mantel tests showed that the floristic composition of the two plots was distinct, even after accounting for the underlying spatial gradient in composition. Nevertheless, some shade tolerant species such as Streblus elongatus and Calophyllum spp. were thriving in the secondary forest. Our findings suggest several possible mechanisms for the slow recovery of the secondary forest, including strong dispersal limitation and the presence of long-lived pioneer species.