Montoya-Pfeiffer, P. M., C. E. Sarmiento, A. Montoya, E. Buenaventura, and J. A. Rodríguez-Rodríguez. “Mangrove Pollinator Functional Diversity Decreases with Patch Size and Landscape Anthropization.” Biotropica 57.5 (2025): e70084.
The y-axis labels in plots for Figure 2e–f are incorrect: They should read “Diversity” instead of “Richness”. The corrected figure is presented here.
Bromeliads provide key microhabitats for many tropical anurans, offering water reservoirs for reproduction and shelter from predators. We investigated the factors influencing anuran occupancy in bromeliad patches in the Atlantic Forest of northeastern Brazil. Over 13 months, we surveyed 100 bromeliad patches, each consisting of 4–104 individual plants, and recorded eight anuran species, all bromelicolous. Contrary to expectations, morphological traits of bromeliads—including species, size, and spatial arrangement—had no significant effect on anuran richness or abundance. Likewise, canopy cover did not significantly influence anuran richness or abundance, and temperature and humidity were excluded from analysis due to low variation across sampling sites. Despite favorable structural conditions, overall species diversity was low. In contrast, the presence of the predatory theraphosid spider Pachistopelma rufonigrum had a strong negative effect on anuran occupancy, emerging as the most influential factor in our models. This predator–prey interaction may contribute to the apparent absence of bromeligenous frog species in the study area. Our findings highlight the role of biotic interactions—rather than habitat structure—in shaping anuran assemblages in bromeliad microhabitats.
Biotropica is pleased to announce its ninth editor, Professor Rhett D. Harrison. Professor Harrison is a senior scientist at CIFOR-ICRAF based in Zambia. He received his PhD from Kyoto University in 2000, studying fig–fig wasp interactions in Borneo, and did postdocs at the Smithsonian Tropical Research Institute, the Research Institute for Humanity & Nature, and the Forest Research Institute Malaysia before taking a position at Xishuangbanna Tropical Botanical Garden in 2009. In 2013, he moved to the Kunming Institute of Botany to head up their laboratory of tropical forest conservation, before moving to Zambia in 2016 with World Agroforestry (ICRAF). He brings a wealth of experience in tropical biology and conservation, studying questions in the fields of landscape ecology, conservation biology, biodiversity, agroecology, and restoration. Through his research, which is invariably transdisciplinary, he has collaborated with a wide variety of people and institutions. Current projects include developing methods for community conservation monitoring in Papua New Guinea and DRC, community forestry in Zambia, Cocoa Agroforestry in Sierra Leone, and agroecological approaches to pest management in southern Africa. In 2006, he set up the Asia-Pacific Chapter of the Association for Tropical Biology & Conservation (ATBC). He has previously served as a subject editor for Ecological Research and the Journal of Plant Research, and Editor-in-Chief for the Malayan Nature Journal. We welcome Dr. Harrison and look forward to his leadership.
Tropical agricultural landscapes can support biodiversity, including forest spill-over species, shaped by habitat factors operating at multiple scales. Understanding these factors is crucial for conserving biodiversity and maintaining ecosystem services. Using mist-netting data, this study examined how land-cover changes influence understorey birds and identified key factors at stand and landscape levels, along with a site-specific feature, affecting bird assemblages in agroforestry orchards, rubber tree, and oil palm plantations in Peninsular Malaysia. We captured 39 species over 9900 netting hours, with forest-associated species comprising 33% of the total. Agricultural type emerged as a primary driver of bird diversity, with agroforestry orchards supporting greater species richness and abundance. Canopy cover negatively influenced species richness, total abundance, and the occurrence of carnivorous/insectivorous and granivorous/frugivorous birds. Understorey vegetation height positively impacted bird total abundance. Elevation negatively influenced bird abundance and the occurrence of omnivores but positively affected forest-associated species. Distance to forest was negatively correlated with bird abundance and the occurrence of omnivorous birds. Our findings highlight agroforestry orchards as avian refuges and biological corridors that enhance landscape connectivity and ecosystem functioning in agricultural areas. Specifically, in our region, dense canopy cover in monoculture plantations reduced bird richness and abundance, likely due to reduced sunlight suppressing understorey vegetation and limiting resource availability. Conversely, agroforestry orchards with more open canopies and structurally complex vegetation supported a greater diversity of feeding guilds, including certain forest-associated species. These results underscore the importance of managing tropical farmland by maintaining understorey growth, increasing canopy heterogeneity, and reducing isolation from forest remnants.
El Niño events can significantly disrupt ecosystem dynamics by altering species distribution, population size, and food web interactions, often leading to biodiversity losses and imbalances in ecological relationships. Although an understanding of El Niño-associated climate and weather changes is critical, their impact on ecological interactions in the tropics remains understudied. We investigated differences in the predation rate of lepidopteran larvae across El Niño phases within an urban-agricultural landscape in Southcentral Mindanao, the Philippines. Our results demonstrate notable variations throughout the El Niño phases. Predation rates were considerably higher in the pre-El Niño phase (mean ± SD = 18.24% ± 13.48%) than during the peak of the El Niño phase (mean ± SD = 6.41% ± 10.20%) and showed a slight, yet statistically insignificant, rise in the post-El Niño phase (mean = 9.48% ± 17.66%). Although predation by arthropods on herbivorous preys remained predominant during all periods, vertebrate predation was related to the warmer and drier conditions of El Niño associated with the 2023 ENSO. Our study provides initial insights into how El Niño events shape prey–predator relationships and sustain key ecological functions through species interactions, laying a crucial foundation for future research on the ecological impacts of El Niño droughts in tropical agro-urban systems. We highlight the importance of considering climate variability in predator–prey dynamics and recommend future studies on long-term recovery, habitat restoration, and climate-adaptive strategies to strengthen ecosystem resilience.
Mycorrhizae can impact soil nutrient cycling, with reduced nitrogen availability and increased litter depth beneath ectomycorrhizal Fagales. The presence of Fagales-dominated montane forests in parts of Asia and Central America could impose a significant barrier to the upslope migration of lowland arbuscular mycorrhizal tree species migrating under climate change.
Tree water use is a critical component of the forest water cycle and is influenced by global climate changes, such as shifts in precipitation patterns. These changes may disproportionately affect forest runoff depending on how sensitive tree water use is to environmental conditions. Therefore, understanding the water-use strategies of different tree species is essential for predicting how forests will respond to environmental change. This study investigated how daily sap flux density (Js), which represents water flow per unit of sapwood area, varies with environmental factors in common tree species in successional tropical forests in Thailand. Using thermal dissipation probes, we measured Js in both an old-growth forest (OF) and a young forest (YF). Results indicated that trees in the OF were highly sensitive to rising vapor pressure deficit (VPD) under low soil moisture, indicating a response to atmospheric demand, while trees in the YF could maintain their water use rate regardless of changes in VPD. In addition, species-specific patterns were observed across varying soil moisture conditions at both sites. In OF, Syzygium syzygoides and Cinnamomum subavenium exhibited conservative water use under low soil moisture, which might protect them from negative effects of droughts. In YF, Adinandra integerrima saturated its Js earlier than other species under low soil moisture, likely to save water, indicating greater drought tolerance compared to others at this site. These findings provide valuable insights into species-specific water-use patterns across different successional stages, helping to predict how tropical forests may respond to environmental changes.
Perubahan pada komposisi dan kepelbagaian spesies dalam konteks kecerunan altitud masih kurang difahami bagi banyak takson tropika. Kajian ini, bertujuan untuk memahami taburan mamalia bersaiz sederhana hingga besar di sepanjang kecerunan altitud di kawasan barat laut Pulau Borneo. Perangkap kamera yang dipasang di 209 stesen dengan menggunakan kaedah pensampelan berstrata merentasi tujuh kategori altitud di enam kawasan terlindung dari tahun 2014 hingga 2017 telah merekodkan 33 spesies mamalia. Bilangan spesies tidak berkait secara signifikan dengan altitud, tetapi komposisinya berubah dengan kesan altitud mengikut takson. Tiada spesies yang direkod di kawasan tanah rendah sahaja, namun kehadiran musang pandan (Paradoxurus hermaphroditus), dua spesies landak (Hystrix crassispinis dan fasciculata) adalah tinggi di altitud rendah. Sebaliknya, kehadiran musang lamri (Paguma larvata), beruk (Macaca nemestrina) dan pulasan tanah (Mustela nudipes) meningkat dengan altitud, manakala musang Hose (Diplogale hosei) dan harimau dahan Sunda (Neofelis diardi) hanya dikesan di kawasan tanah tinggi (> 700 m). Perbezaan aktiviti bagi sesetengah spesies antara hutan altitud rendah dan tinggi adalah kecil. Secara amnya kebanyakan spesies yang di kesan mempunyai julat altitud yang luas. Walau bagaimanapun, perlindungan hutan di sepanjang kecerunan altitud tersebut adalah penting dalam menghadapi perubahan iklim, dimana kesinambungan habitat tersebut adalah perlu sekiranya spesies terpaksa berhijrah dari tanah rendah ke altitud yang lebih tinggi.
Scaling relationships between different axes of tree size, such as height, crown radius, crown depth, and stem diameter, play a direct role in shaping forest structure and function. Theoretical models such as metabolic scaling theory postulate that they are optimized for biomechanical stability and hydraulic sap distribution. However, empirical data often show that such models are only good enough as first-order approximations because they do not account for differences in species traits and environmental conditions where trees grow. Nevertheless, the vast majority of research has focused on temperate ecosystems or tropical rainforests, so we continue to lack a full understanding of what factors shape allometries of trees in tropical dry forests. Here, we compile data on tree height, diameter, crown radius, and depth from miombo woodlands across Zambia and use a Bayesian hierarchical modeling framework to explore how allometric scaling relationships are shaped by climate and competition. Similar to previous studies, our results revealed that allometric scaling relationships deviate substantially from theoretical expectations. We found that competition, precipitation, and temperature all affect crown allometric scaling relationships, with trees becoming more slender where neighborhood competition was greater, while crowns were wider and deeper in warmer and wetter climates. Our study highlights how the structure and function of miombo woodlands is shaped by more than just water availability. Moreover, by developing improved crown allometric models for miombo woodlands, we provide new tools to aid the estimation of aboveground biomass and calibration of remote sensing products in these critically important dry forest ecosystems.
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