Masting effect on alpha and beta avian diversity in fragmented forests of relict-endangered Mexican Beech (Fagus grandifolia subsp. mexicana)

Background Tropical montane cloud forests are one of the most important hotspots on Earth and show presence of relict-endemic and endangered species, representing about 14% of the total tropical forest worldwide. Synchronous seed production or masting in tropical montane cloud tree species is a widespread reproductive strategy of deciduous and evergreen broad-leaved tree associations to decrease costs of reproduction and ensure offspring. Masting event maintains a high avian diversity, which can be modified by phenological process (seed production and non-seed production). Methods The main aim of this study was to assess alpha and beta avian diversity and whether the composition of the trophic guild modifies among phenological processes and between two fragmented relict-endangered Mexican Beech (Fagus grandifolia subsp. mexicana) forests (Medio Monte and El Gosco) in the Mexican state of Hidalgo. In addition, we evaluated beechnut production. Results We recorded 36 bird species, 11 of them included in some conservation risk status, and 5 endemic species. Alpha diversity values were dissimilar in avian richness (q = 0) among phenological processes and between fragmented beech forests. Avian communities among three phenological processes and between fragmented forests were structurally similar, dominated during immature seeds the Brown-backed Solitaire (granivores–insectivores–frugivores); during mature seeds the White-crowned Parrot (Pionus senilis, granivores–frugivores); and the Dwarf Jay (Cyanolyca nana, insectivores) was abundant during low seed quality. The complementarity index was high among phenological processes and low between forests. We found a high bird turnover value between immature seeds—mature seeds and during mature seeds—low seed quality. Furthermore, a similar pattern was recorded between the two study forests. Seed production showed a high number of undamaged beechnuts in Medio Monte, while in El Gosco beechnuts were attacked by insects. Conclusions Our results reflect that masting phenological process and contrasting study forests’ structure influence the shifts in alpha and beta diversity of seed and non-seed bird consumers. Our study reaffirms the importance of continuing studies throughout masting in all the Mexican Beech forests to address regional efforts in preserving the relict-ecological interactions.

Forest Fragmentation Slows the Decomposition of Coarse Woody Debris in a Subtropical Forest

Forest fragmentation is increasing rapidly around the world, and edge effects caused by fragmented forests can influence ecosystem functions and ecological processes, including coarse woody debris (CWD) decomposition. Understanding the influencing mechanisms of edge effect on CWD decomposition is needed to assess the effects of forest fragmentation on carbon cycling and storage. We measured rates of mass loss of CWD of Cinnamomum camphora (L.) Presl. and Pinus taiwanensis Hayata over two years at two distances (0−5 m versus 60 m) from a forest edge at two altitudes (215 and 1,400 m a.s.l.), in a subtropical forest. In addition, we determined the microbial community of each CWD segment and the soil beneath via phospholipid fatty acids (PLFAs). Mass loss of CWD 60 m from the forest edge was 15% greater than that at the edge (0–5 m). Mass loss was positively correlated with the abundance of microbial and fauna community and moisture content of the decaying CWD. Distance from edge explained 17.4% of the total variation of the microbial abundance in CWD. The results indicate that the reduced abundance of microbial and fauna communities and moisture content at forest edges influenced rates of decomposition of CWD. Long-term experiments with more tree species and more forest types are needed to better assess edge effects generally. Study Implications Forest fragmentation is increasing rapidly around the world, and edge effects caused by fragmented forests can influence ecosystem functions and ecological processes, including coarse woody debris (CWD) decomposition. Understanding the influencing mechanisms of edge effect on CWD decomposition is needed to assess the effects of forest fragmentation on carbon cycling and storage. The results of this study indicate that the reduced abundance of microbial and fauna communities and moisture content at forest edges reduced rates of decomposition of CWD. Long-term experiments with more tree species and more forest types are needed to assess the edge effect’s generality.

Roller dung beetles of dung piles suggest habitats are alike, but that of guarding pitfall traps suggest habitats are different

Roller dung beetles play a pivotal role in the nutrient distribution in soil and secondary dispersal of seeds. Dung beetles are sampled either using a dung-baited pitfall trap or an exposed dung pile on the ground. While the former method is useful for a rapid survey of dung beetles, information on the ecology and behaviour of dung beetles can be lost, which the latter method provides, but underestimates species diversity due to its inefficiency in trapping rollers. Efficiency of a new method for sampling rollers—installing guarding pitfall traps around dung piles—is assessed in three habitats—contiguous tropical rainforests, fragmented forests, and disturbed used home gardens—and two diel periods—day and night. Five guarding pitfall traps were installed at 50 cm radius around dung piles. About 98% of the total rollers were sampled in pitfall traps. The habitats were similar when the roller catches of only dung piles—conventional approach—were analyzed, but were different when the rollers of guarding pitfall traps were considered. The roller abundance was negatively affected by forest fragmentation and land-use change. About 98% of the rollers were collected at daytime. Using guarding pitfall traps around dung piles is highly recommended for dung beetle diversity studies.

Structure and tree species composition of forest fringe of a forest fragment in an oil palm plantation at Suai, Sarawak, Malaysian Borneo

Jana CL, Jusoh I. 2021. Structure and Tree Species Composition of Forest Fringe of A Forest Fragment in an Oil Palm Plantation at Suai, Sarawak, Malaysian Borne. Biodiversitas 22: 3013-3019. Forest fragments in oil palm plantations are remnants of the original forest tract with various sizes and shapes after clearing forested lands for crops and roads. Fragmented forests usually created forest fringe or edge habitats that differ in light intensity, temperature, humidity, heavy rainfall, and strong winds from its core. The study was aimed to determine the structure and tree species composition of the forest fringe of a fragmented forest in an oil palm plantation Suai, Sarawak. This study established a total of 24 sampling plots within the forest fringe. Tree enumeration and species identification were conducted in all sampling plots to all trees with a diameter at breast height 5 cm and higher. A total of 59 families comprised of 274 species and 948 trees individuals were recorded. The aboveground biomass stand at 260 Mg ha?¹. Species Elateriospermum tapos was predominant, and family Dipterocarpaceace dominated the forest fringe. Based on the calculated indices, species diversity and richness were considered high, while the dispersion of individual trees was random but unevenly distributed. Natural regeneration in the forest fringe is sustainable. The forest structure and species composition are intact, and without significant disturbance, the whole forest fragment is self-sustain.

Decline in Aboveground Biomass Due to Fragmentation in Subtropical Forests of China

Fragmentation has long been considered the primary cause for ecosystem degradation and biodiversity loss worldwide. Forest fragmentation affects ecosystem functioning and biodiversity in multiple ways. Here, we ask how forest fragmentation influences aboveground biomass storage (AGB) in sub-tropical forests in China. We established 207 20 m × 20 m plots within 69 forest fragments of varying size. Forest fragmentation process simulation was carried out via repeated quadrat sampling using different sized quadrats in two non-fragmented stands. AGB was estimated and compared across forest fragments and quadrats with different sizes within two non-fragmented stands. Our results indicate that AGB is significantly lower in forest fragments than in quadrats within two non-fragmented forests. In addition, species richness and abundance were lower in fragmented stands, respectively. In fragmented forests, the average diameter at breast height (DBH) increased with decreasing patch size, while declined for non-fragmented plots. Species richness, abundance, and mean DBH have strongly positive effects on AGB. This was the case both in forest fragments and quadrats within two non-fragmented forests. Forest fragmentation leads to lower richness, lower abundance, and higher mean DBH in forest fragments than in the two non-fragmented forests. Our results suggest that forest fragmentation increases edge habitats, which drastically decreases forests aboveground biomass storage. These results show that land degradation not only reduces the area of forests, but also reduces the aboveground biomass carbon density of forests.

Comparison between terrestrial mammals in evergreen forests and in seasonal dry forests in Western Ecuador: should efforts be focused on dry forests?

The Coast Region of Ecuador has been dramatically deforested, and most of the remaining natural vegetation is formed of fragmented patches, in which there is little knowledge of wild mammal populations. The objective of this study was to assess the presence and detection rate (DR) of medium and large-size mammals by using camera-traps in fragmented forests located outside the protected areas comparing the two main types of forest: seasonal dry and evergreen. We registered 18 different species, of which four had greater DRs in dry forests (Lycalopex sechurae, Odocoileus peruvianus, Simosciurus stramineus and Sylvilagus daulensis), four were more detected in evergreen forests (Cuniculus paca, Dasyprocta punctata, Dasypus novemcinctus and Procyon cancrivorus), and the remaining 10 species had no significant habitat preference. The mean species richness was similar in both ecosystems, but the number of detections was greater in the evergreen forests. Finally, two of the region’s four threatened species had higher DRs in dry forests. These results suggest that it is necessary to conserve both types of ecosystems to ensure the conservation of all mammals’ species. However, since dry forests are less protected and their threatened fauna suggests that conservation efforts should be particularly focused on them.

New Records of Polymita venusta (Gmelin, 1792) Populations in Northern Foothills of Sierra de Boniato, Santiago de Cuba Province

Three new localities of Polymita venusta are uncovered from the northern foothills of Sierra de Boniato in the Santiago de Cuba province. In those, five new populations inhabiting fragmented forests over karstic substratum were found between 238-405 meters above sea level. The rediscovery of a unique color form took place in one colony from the La Luz vicinity. These populations occupy a highly deforested area where the main activities are cattle grazing and agriculture, combined with other anthropic threats. Protected Areas planning for this human highly disturbed zone is nonexistent.