Tropical Rainforest Research Articles

Global rarity of high-integrity tropical rainforests for threatened and declining terrestrial vertebrates

Structurally intact native forests free from major human pressures are vitally important habitats for the persistence of forest biodiversity. However, the extent of such high-integrity forest habitats remaining for biodiversity is unknown. Here, we quantify the amount of high-integrity tropical rainforests, as a fraction of total forest cover, within the geographic ranges of 16,396 species of terrestrial vertebrates worldwide. We found up to 90% of the humid tropical ranges of forest-dependent vertebrates was encompassed by forest cover. Concerningly, however, merely 25% of these remaining rainforests are of high integrity. Forest-dependent species that are threatened and declining and species with small geographic ranges have disproportionately low proportions of high-integrity forest habitat left. Our work brings much needed attention to the poor quality of much of the forest estate remaining for biodiversity across the humid tropics. The targeted preservation of the world's remaining high-integrity tropical rainforests that are currently unprotected is a critical conservation priority that may help alleviate the biodiversity crisis in these hyperdiverse and irreplaceable ecosystems. Enhanced efforts worldwide to preserve tropical rainforest integrity are essential to meet the targets of the Convention on Biological Diversity's 2022 Kunming-Montreal Global Biodiversity Framework which aims to achieve near zero loss of high biodiversity importance areas (including ecosystems of high integrity) by 2030.

The analysis of climate change and human activities in the Brazilian Amazon forest

In recent years, global warming has significantly altered weather patterns in many countries. Brazil, home to the biggest tropical rainforest on Earth the Amazon Forest, has experienced an uptick in extreme climate events, which has increasingly captured global attention. Human activities may contribute to phenomena such as the greenhouse effect, acid rain, and the depletion of the ozone layer. Additionally, the increasing frequency of extreme weather events has led to issues related to agricultural yield, infectious diseases, and other related problems. This article primarily explores the changes in climatic conditions of the Amazon Forest in Brazil and the measures the government ought to take. Through a review of the literature, this report examined the changes in temperature, precipitation, vegetation coverage, and fire in the Amazon Forest in Brazil in recent years, as well as the interconnections among these factors. Besides, this article also offers recommendations for addressing the more severe drought and frequent fires in the Brazilian Amazon Forest.

Effects of two Bacillus velezensis strains isolated from different sources on the growth of Capsicum annum

Microbial inoculants offer an environmentally friendly approach to enhance plant growth and control disease. In this study, two Bacillus velezensis strains, HKSSLJEBR3 (R3) and Ya-1 were isolated from pepper plant roots and tropical rainforest soil, respectively. Both strains exhibited strong antifungal activity against Fusarium oxysporum f. sp. capsici, with inhibition rates of 48.54 ± 0.66% for R3 and 49.35 ± 1.44% for Ya-1. In greenhouse trials, R3 significantly boosted pepper growth, with a 22.12% increase in plant height, 46.44% more leaves, and 56.29% greater fresh weight. These enhancements were likely due to the strong affinity between R3 and pepper plants. Both strains also improved soil quality, with R3 increasing available potassium (AK) by 5.13% and soil organic matter (SOM) by 4.03%, while Ya-1 showed more significant increases. Metagenomic analysis revealed that both strains altered the rhizosphere microbiome, with R3 promoting Pseudomonas and suppressing Fusarium. These results suggest that the R3 strain has strong potential for enhancing pepper growth, improving soil health, and reshaping the rhizosphere microbiome.

New Records and Ecological Observations of the Previously Unreported Small Long-fingered Bat (Miniopterus pusillus) in Kerala, India

This research contributes to the conservation efforts by shedding light on the presence of Miniopterus pusillus in Kerala, highlighting the need for continued habitat protection and species-specific studies. This study expands the bat species checklist of Kerala by documenting the previously unreported presence of Miniopterus pusillus. The study, conducted from 2016 to 2019 in the Idukki and Ernakulam districts of Kerala, India, covered three forest divisions: Malayattoor, Munnar, and Mankulam, characterized by diverse ecosystems, including tropical evergreen and semi-evergreen forests, moist deciduous forests, grasslands, and montane shola ecosystems. Morphologically, M. pusillus exhibits several distinct features that differentiate it from other insectivorous bats. These include a gracile skull, a slender jaw, a reduced coronoid process, a less developed sagittal crest, and a lower number of teeth. Miniopterus pusillus, commonly known as the Small long-fingered bat, is a rare species within the family Miniopteridae. This article emphasizes the potential for further research in the less-explored regions of the Western Ghats, underscoring the need for comprehensive biodiversity assessments in these areas.

Leaf warming in the canopy of mature tropical trees reduced photosynthesis due to downregulation of photosynthetic capacity and reduced stomatal conductance.

Tropical forests play a large role in the global carbon cycle by annually absorbing 30% of our annual carbon emissions. However, these forests have evolved under relatively stable temperature conditions and may be sensitive to current climate warming. Few experiments have investigated the effects of warming on large, mature trees to better understand how higher temperatures affect these forests in situ. We targeted four tree species (Endiandra microneura, Castanospermum australe, Cleistanthus myrianthus and Myristica globosa) of the Australian tropical rainforest and warmed leaves in the canopy by 4°C for 8 months. We measured temperature response curves of photosynthesis and respiration, and determined the critical temperatures for chloroplast function based on Chl fluorescence. Both stomatal conductance and photosynthesis were strongly reduced by 48 and 35%, respectively, with warming. While reduced stomatal conductance was likely in response to higher vapour pressure deficit, the biochemistry of photosynthesis responded to higher temperatures via reduced Vcmax25 (-28%) and Jmax25 (-29%). There was no shift of the Topt of photosynthesis. Concurrently, respiration rates at a common temperature did not change in response to warming, suggesting limited respiratory thermal acclimation. This combination of physiological responses to leaf warming in mature tropical trees may suggest a reduced carbon sink with future warming in tropical forests.

Drivers of biomass stocks and productivity of tropical secondary forests.

Young tropical secondary forests play an important role in the local and global carbon cycles because of their large area and rapid biomass accumulation rates. This study examines how environmental conditions and forest attributes shape biomass compartments and the productivity of young tropical secondary forests. We compared 36 young secondary forest stands that differed in the time since agricultural land abandonment (2.3-3.6 years) from dry and wet regions in Ghana. We quantified biomass stocks in living and dead stems, roots, and soil, and aboveground biomass and litter productivity. We used structural equation models to evaluate how macroclimate, soil nutrients (N, P), and forest attributes (structure, diversity, and functional composition) affect ecosystem functioning. After three years of succession, tropical wet forests stored on average 115 t biomass ha-1 (the sum of aboveground living and dead biomass, belowground fine root biomass, and soil organic matter), and dry forests stored 99 t ha-1. These values represent 31% (in the wet forest) and 39% (in the dry forest) of the biomass compared with neighboring old-growth forests. The majority of forest ecosystem biomass was stored in the soil (70%) and aboveground living vegetation (25%). Macroclimate strongly shaped forest attributes, which in turn determined biomass stocks and productivity. Soil phosphorus strongly increased litter production and soil organic matter, confirming that it is a limiting element in tropical ecosystems. Tree density and species diversity increased forest biomass stocks, suggesting crown packing and complementary resource use enhance forest functioning. A more conservative trait composition (high wood density) increased biomass stocks but reduced productivity, indicating that quantity, identity, and quality of species affect ecosystem functioning.

Tree species controls over nitrogen and phosphorus cycling in a wet tropical forest

AbstractWet tropical forests play an important role in the global carbon (C) cycle, but given current rates of land‐use change, nitrogen (N) and phosphorus (P) limitation could reduce productivity in regenerating forests in this biome. Whereas the strong controls of climate and parent material over forest recovery are well known, the influence of vegetation can be difficult to determine. We addressed species‐specific differences in plant traits and their relationships to ecosystem properties and processes, relevant to N and P supply to regenerating vegetation in experimental plantations in a single site in lowland wet forest in Costa Rica. Single‐tree species were planted in a randomized block design, such that climate, soil (an Oxisol), and land‐use history were similar for all species. In years 15–25 of the experiment, we measured traits regarding N and P acquisition and use in four native, broad‐leaved, evergreen tree species, including differential effects on soil pH, in conjunction with biomass and soil stocks and fluxes of N and P. Carbon biomass stocks increased significantly with increasing soil pH (p = 0.0184, previously reported) as did biomass P stocks (p = 0.0011). Despite large soil N pools, biomass P stocks were weakly dependent on traits associated with N acquisition and use (N2 fixation and leaf C:N, p < 0.09). Mass‐balance budgets indicated that soil organic matter (SOM) could supply the N and P accumulated in biomass via the process of SOM mineralization. Secondary soil P pools were weakly correlated with biomass C and P stocks (R = 0.47, p = 0.08) and were large enough to have supplied sufficient P in these rapidly growing plantations, suggesting that alteration of soil pH provided a mechanism for liberation of soil P occluded in organo‐mineral soil complexes and thus supply P for plant uptake. These results highlight the importance of considering species' effect on soil pH for restoration projects in highly weathered soils. This study demonstrates mechanisms by which individual species can alter P availability, and thus productivity and C cycling in regenerating humid tropical forests, and the importance of including traits into global models of element cycling.

Molecular Identification of Mosquitoes (Diptera: Culicidae) Using COI Barcode and D2 Expansion of 28S Gene

The purpose of this study is to improve the identification of Culicidae species from the Vale Ribeira region, São Paulo state, Brazil. Adults were collected in the municipalities of Cananeia and Pariquera-Açu and morphologically identified. Molecular analyses were performed on sequences of COI barcode and a fragment of the D2 expansion of the 28S ribosomal RNA gene generated from field collected mosquitoes. The analyses included species delimitation, phylogeny, and interspecific genetic distances using the Kimura 2-parameter model. Species included in the analyses were Aedes perventor, Aedes scapularis, Aedes serratus/Aedes nubilus, Aedes serratus s.s., Aedes terrens, Haemagogus capricornii, Haemagogus leucocelaenus, Haemagogus janthinomys, Kerteszia bellatrix, Kerteszia cruzii, Psorophora ferox, Psorophora forceps, Sabethes conditus, and Wyeomyia confusa. COI sequences from specimens collected at other localities were included in the analysis for comparison. Results of barcode RESL analysis showed that specimens of Ps. ferox and Hg. janthinomys split into three clusters for each species. Similarly, sequences of Ke. bellatrix and Ke. cruzii were recovered in two groups for each species. Distinct from other species included in analyses, Ps. ferox and Ps. forceps shared 100% similarity in the D2 fragment sequenced. Overall, the analysis of COI barcode sequences revealed the following key findings: (1) the presence of subclades within Hg. janthinomys, with its division into three groups suggests that this species may represent a species complex; (2) Ke. bellatrix from the Atlantic tropical rainforest shares 95.59% sequence similarity with a specimen from the type locality, indicating that specimens from Southeastern Brazil may belong to an unidentified species within the Ke. bellatrix complex; (3) Ke. cruzii also represents a species complex; and (4) D2 sequences successfully identified most species studied, apart from Ps. forceps and Ps. ferox.

Influence of climatic variables on biome transitions in the COLOMBIAN and PANAMANIAN Caribbean region

Disentangling the environmental determinants of tropical biomes is crucial for understanding their response to climate change. This study investigated the effect of climate and soil-related variables on biome transitions in the Caribbean region of Colombia and Panama, focusing on xerophytic forest (XF), tropical dry forest (TDF), and tropical rainforest (TRF). We analyzed the climatic variables at different time scales (daily, seasonal, and annual) and their interaction with soil properties. We performed an ordinal logistic regression to assess the combined effect of the most important variables in biome transitions. Our results showed that climate variables are major discriminators in our study region, particularly precipitation at a seasonal and annual scale. The ordinal logistic regression highlighted the significance of annual precipitation and dry-season length in biome transitions, with maximum temperature impacting TDF-TRF transitions. Soil differences, although present (e.g., higher sand content in XF), played a marginal role. Overall, our findings emphasize the dominance of climate over soil in shaping tropical biome distributions in the northern Caribbean part of South America. These findings contribute to a deeper understanding of tropical biome responses to climate change.

Taxonomy, systematics and conservation of the highly threatened and endemic Mexican genus Tridimeris (Annonaceae)

Tridimeris is the only genus of Annonaceae endemic to Mexico, and since its description more than 150 years ago, the genus has been largely ignored. Here, based on herbarium specimens and a comprehensive phylogenomic study involving hundreds of nuclear markers, the first taxonomic revision of the genus Tridimeris (Annonaceae, Malmeioideae, subtribe Sapranthinae) is presented. Ten species are recognized, six of which are newly described here. All the species are exclusively found in Mexico's most humid forests, particularly in the montane cloud forest and the tropical rainforest. The genus Tridimeris is morphologically distinguished from other neotropical genera of the Annonaceae by its leaves with pocket domatia present in the axils of the secondary veins, by its dimerous flowers (two sepals and four petals), basally fused sepals with ciliated margins, by a reduced number of carpels per flower (1–5) and by its large and fleshy fruits (monocarps) with numerous seeds. A highly resolved phylogenetic hypothesis provides strong support for the relationships among Tridimeris species, forming two well-supported clades. Consequently, two new sections are proposed, namely Tridimeris sect. Tridimeris and Tridimeris sect. Zoque. A detailed description of the morphology of the genus is presented, including the description of the pollen, domatia and its phylogenetic relationships. Taxonomic treatments of the species include synonyms, geographic and ecological notes, comparisons with similar species and a preliminary assessment of their conservation status. All species of the genus are potentially threatened with extinction and eight are assessed as Critically Endangered, which makes it the most threatened lineage of Mexican trees. This study emphasizes the importance of scientific collections as invaluable sources of data for current taxonomic revisions and conservation. It is a formal invitation to preserve and support the basic scientific research.

Resilience Indicators for Tropical Rainforests in a Dynamic Vegetation Model.

Tropical forests and particularly the Amazon rainforest have been identified as potential tipping elements in the Earth system. According to a dynamical systems theory, a decline in forest resilience preceding a potential shift to a savanna-like biome could manifest as increasing autocorrelation of biomass time series. Recent satellite records indeed exhibit such a trend and also show larger autocorrelation, indicative of reduced resilience, in drier forest regions. However, it is unclear which processes underlie these observational findings and on which scales they operate. Here, we investigate which processes determine tropical forest resilience in the stand-alone, state-of-the-art dynamic global vegetation model LPJmL. We find that autocorrelation is higher in dry climates than wet climates (approx. 0.75 vs. 0.2, for a lag of 10 years), which qualitatively agrees with observations. By constructing a reduced version of LPJmL and by disabling and enabling certain processes in the model, we show that (i) this pattern is associated with population dynamics operating on different time scales in different climates and (ii) that the pattern is sensitive to the allocation of carbon to different pools, especially in years of stress. Both processes are highly uncertain, oversimplified or even lacking in most Earth system models. Our results indicate that the observed spatial variations and trends in vegetation resilience indicators may be explained by local physiological and ecological mechanisms alone, without climate-vegetation feedbacks. In principle, this is consistent with the view that the Amazon rainforest is responding to climate change locally and does not necessarily need to approach one large-scale tipping point, although the latter cannot be ruled out based on our findings.

First report of Caloboletus guanyui (Boletaceae) in India: Taxonomic and phylogenetic insights from Mizoram

The family Boletaceae primarily consists of ectomycorrhizal fungi, which are essential for maintaining the health of forest ecosystems. These fungi form symbiotic relationships with trees, facilitating nutrient exchange and en?hancing plant growth. In the present study, specimens of Caloboletus guan?yui were collected from the Mizoram University campus during the rainy season of 2023. Identification was based on both morphological characteris?tics and molecular analysis of the ITS region of rDNA, with phylogenetic analysis further confirming the distinctiveness of Caloboletus guanyui from closely related species within the genus Caloboletus Vizzini. This medium?sized to large bolete is characterized by its dirty-white to pale-brown pileus and the basidiospores are elliptic-fusiform (spindle-shaped) to subfusiform 9.5–11.5 × 3.5–4.5 ?m. This study represents the first recorded occurrence of Caloboletus guanyui in the tropical moist deciduous forests of Mizoram, India, thereby expanding the known distribution of this species. These new findings enhance our understanding of bolete diversity in India, particularly within the unique forest ecosystems of Mizoram.

The effect of soil microbial functional groups, abiotic and biotic factors on plant functional groups: insights from a tropical rainforest in Southwest China

The effect of soil microbial functional groups, abiotic and biotic factors on plant functional groups: insights from a tropical rainforest in Southwest China

Gonadal Maturation and Reproductive Timing in Batch Spawning Tropical Cypriniform Fishes Lobocheilos ovalis, Rasbora argyrotaenia and Tor tambra

ABSTRACTThis study is the first to investigate the reproductive traits of Lobocheilos ovalis (n = 621), Rasbora argyrotaenia (n = 507) and Tor tambra (n = 138) through detailed gonad histology. We collected L. ovalis and R. argyrotaenia specimens from September 2017 to August 2019 and T. tambra from July 2018 to August 2019 from tropical rainforest streams in Ulu Temburong National Park Brunei Darussalam. In all three species, females were larger and attained sexual maturation at larger sizes than males. Gonad histology categorized five reproductive phases in the ovarian and testicular maturation cycle comprising the immature, developing, spawning capable, regressing and regenerating phases. Ovarian histological markers of the reproductive phases included increasing oocyte diameters and gradual changes in cytoplasmic and nuclear features. In testes, decreasing nuclear diameters, darkening nuclear stains and germinal epithelium continuity were significant histological markers. Monthly frequencies of reproductive phases showed that L. ovalis and R. argyrotaenia were reproductively active throughout the year, whereas T. tambra exhibited protracted spawning over several months. Gonad histology also revealed asynchronous ovarian development and batch spawning, facilitating these species’ year‐round and protracted spawning. This reproductive strategy may be an adaptation for these species to increase the survival of offspring in hillstream habitats where flash floods are common. The present study significantly fills existing knowledge gaps in Southeast Asian cypriniform fishes, providing a reference point for gonad histology to elucidate the reproductive traits and ecology, particularly for the Lobocheilos, Rasbora and Tor genera. Importantly, it provides practical insights for the conservation and management of the wild populations of these species.

The fight against malaria in Edo-North, Edo State, Nigeria: identifying risk factors for effective control.

This study investigated malaria epidemiology in Edo-North, Nigeria; a region within the equatorial rainforest belt that has lacked prior research on malaria prevalence. This research sought to investigate the prevalence of malaria and identify potential risk factors in Edo-North, Nigeria. Additionally, the study aimed to analyze trends in malaria cases to inform the development of effective malaria control measures. A cross-sectional study was conducted in six local government areas of Edo-North, Nigeria, between June and August 2023. Using systematic sampling, study zones, local governments, towns, villages, and households were selected. Data on sociodemographics and environmental risk factors were collected from 605 participants through questionnaires and blood samples. Blood smears were microscopically examined, binary and multivariate logistic regression was used for data analysis. Malaria disease rate trends were also analyzed from health records. Statistical analyses were performed using R software, with p-values less than 0.05 considered statistically significant. The overall malaria prevalence in the study area was 15.54%, with males more likely to be infected than females. Prevalence varied across localities, with Akoko-Edo having the highest rate. Children had the highest prevalence. Rural residents were more likely to have malaria than urban residents. Binary logistic regression identified several risk factors, including age, location, local government area, education, occupation, marital status, housing type, household size, water source, sanitation, surrounding environment, window net use, ceiling type, water storage, and parasite density. The multivariate logistic regression analysis identified several significant risk factors for malaria in the study population. Children, residents of Owan-East, individuals using pit latrines, and those not sleeping under LLINs were at significantly increased risk. Environmental factors such as proximity to bushes, streams/rivers, and storing water in open containers were also associated with higher malaria prevalence. History of malaria treatment at pharmacies and use of Chloroquine/Quinine medication were linked to recurrent infections. The study found a high average parasite density (5,146 parasites/μL) and low consistent LLIN use despite widespread ownership. Trend analysis from malaria records revealed a decline in malaria prevalence from 2020 to 2023. The study identified several demographic, environmental and behavioural factors associated with malaria risk in Edo North. Males, children, urban dwellers, those living in mud houses and those in large households, proximity to natural features such as bushes, rivers and streams and low LLIN were more likely to contract malaria. These findings highlight the importance of implementing targeted interventions to address these risk factors and reduce the burden of malaria.

Assessing multi-decadal climatic variability and its impact on cardamom cultivation in the Indian Cardamom Hills.

This study examines the multi-decadal variability and trends of surface air temperature and precipitation in the Indian Cardamom Hills (ICH), a degraded tropical rainforest area unique for cardamom cultivation. Utilizing observed long-term climatic data (1958-2017), statistical methods such as the Mann-Kendall test (MKT), Sen's Slope Estimator (SSE), and Incremental Trend Analysis (ITA) were applied to assess the impact of surface air temperature, rainfall, and the number of rainy days on cardamom yield. The analysis revealed a significant decline in annual rainfall by approximately 13.62mm per year, with pronounced seasonal declines 0.87mm for winter, 12.33mm for pre-monsoon, 24.93mm for southwest monsoon, and 18.10mm for post-monsoon. Simultaneously, the number of rainy days dropped by nearly 19.75days over the 40-year period. A noticeable increase in decadal minimum and average temperatures was observed, highlighting potential adverse effects on cardamom yield and irrigation water resources. The findings suggest that excessive rainfall during the southwest monsoon negatively correlates with cardamom yield, while slightly warmer temperatures show a weak positive correlation. The study also emphasizes the need for adaptive agricultural practices and climate-resilient policies to mitigate the effects of changing climatic conditions on cardamom production. This research contributes valuable insights for farmers and other stakeholders as well as policymakers aiming to ensure sustainable cardamom cultivation amidst climate change.

Finding Spalting Fungi in the Peruvian Tropical Premontane Cloud Forest on Peruvian Native Wood Species

Tropical montane and premontane forests are diverse, including fungi. However, little is known about spalting fungi (decay fungi that change the color of wood) in tropical regions despite the economic importance they could bring by enhancing wood esthetics. To increase the knowledge of the diversity of spalting fungi, a sampling of fallen logs, branches (exposing xylem to identify potential pigmenting and zone line-producing fungi), and fruiting bodies (on wood) was conducted in the premontane moist forest in the district of San Ramon, Junín, Peru. The fungi were collected, cultured, isolated, and sequenced. Also, the identified species were used in a novel test to confirm they were producing spalting on Guazuma crinita. The species found belong to the Ascomycota orders Xylariales and Diaporthales and the Basidiomycota orders Agaricales, Polyporales, and Russulales. The fungi collected produced bleaching, different colors of zone lines, and pigmentation in laboratory conditions. The results increase the database of spalted fungi in Peru, and the test used in this research could be the basis for a quick test to identify spalting fungi.

Biogeographical Origins of Caatinga Squamata Fauna

ABSTRACTAimSeveral lines of evidence have noted that open vegetation biomes in the Neotropics are younger than moist forests, leading us to question which historical processes shaped the current species distribution patterns in these new biome formations. Here we investigate the temporal patterns of speciation and colonisation from surrounding biomes (Amazonia, Atlantic Forest and Cerrado) in the Caatinga historical assembly of squamate species, to understand the role of geomorphological events and climate change in driving its diversification.LocationNeotropics.TaxonSquamata (snakes, lizards and amphisbaenians).MethodsWe used a phylogenetic tree and occurrence data for 459 squamate species distributed throughout four different biomes (Amazonia, Atlantic Forest, Cerrado and Caatinga) to reconstruct ancestral geographic ranges using the R package BioGeoBEARS. We used BAMM to estimate the rates of species diversification.ResultsOur results indicate that the current diversity patterns of squamates in the Caatinga were a result of pervasive faunal exchanges from adjacent biomes since the Paleogene, with similar numbers of dispersal events in each source area. The Neogene period was determinant in the diversification process, leading to the current assembly patterns of this group in the Caatinga.Main ConclusionsThe landscape transformation and climate change that increased aridity in northeastern Brazil probably shaped the diversification of dry‐adapted squamates in the Caatinga, like tropidurid lizards. However, the Pleistocene climatic fluctuations associated with the highly heterogeneous gradients of topography, geology, soils, climatic conditions, and different vegetation physiognomies could have facilitated faunal exchange with their neighbouring forested biomes, explaining the current presence of some typical forested lineages inside the Caatinga domain and help us to clarify the current distribution patterns of squamates in this region.

Spatiotemporal Correlation Analysis of Landscape Pattern and Habitat Quality in and Around China’s Tropical Rainforest National Park

With the establishment of the national park system in China, balancing ecological conservation within national parks and development in surrounding areas has become a critical issue. Despite its importance, studies on the scale effects of landscape fragmentation and its relationship with habitat quality (HQ) in these regions remain scarce. Therefore, this study focuses on the Hainan Tropical Rainforest National Park (HTRNP) in China and the surrounding nine cities and counties. The optimal scale for analyzing the spatiotemporal characteristics of landscape patterns, we assessed the best grain size and extent of landscape pattern indices using the regional information loss assessment model, area loss index, and semivariance function analysis. Based on this, the Fragstats and InVEST models analyzed the spatiotemporal evolution of landscape patterns and HQ from 1980 to 2020. Additionally, bivariate spatial autocorrelation theory was applied to examine the spatial correlation between the two. The results show that (1) the landscape indices in the study area vary with grain size and extent. The optimal grain size is 300 m, and the optimal extent is 2 km × 2 km. (2) Over the past 40 years, the landscape pattern of HTRNP has remained stable. In contrast, the surrounding areas exhibit notable spatial differentiation, with landscapes in coastal town centers becoming increasingly fragmented. (3) Over the past 40 years, the overall HQ in the study area has been relatively high, showing a spatial distribution pattern that decreases gradually from the center of HTRNP outward to rural areas, towns, and coastal regions. HTRNP has maintained a high and stable HQ, while the surrounding areas exhibited a decreasing trend in HQ, although the decline was relatively modest. (4) The spatial distribution of HQ aligns closely with landscape patterns, indicating a significant spatial correlation. The landscape connectivity of HTRNP remains high, with consistently superior HQ. In contrast, coastal town centers are characterized by highly fragmented landscapes and poor HQ. This study reveals the spatiotemporal dynamics of landscape patterns and HQ, along with their spatial associations. These findings provide a scientific basis for ecological conservation in national parks and the planning optimization of surrounding areas.

Regeneración natural de la selva alta perennifolia en cultivos abandonados de café (<i>Coffea arabica</i> L.) en Veracruz, México

Background: The tropical rain forest (TRF) has been transformed by the land use change. Coffee plantations are part of the landscape, and their abandonment can favor the original vegetation regeneration. Hypothesis: The abandoned coffee plantations protection in TRF favors natural regeneration, allowing the development of secondary forests in different succession phases. Study site: Colipa, Veracruz, Mexico. Two abandoned coffee plantations and a fragment of TRF. Methods: In 24 transects (50 × 2 m), diameters and heights of woody species (DBH ≥ 5 cm) were recorded and measured. In each transect, quadrants (2 × 2 m) were marked to record shrub and seedlings species. Regeneration status was evaluated through densities of seedlings, juveniles and adults. Results: 60 species were recorded. The highest number of species was present in the TRF and the nearby coffee plantation, they were the sites with the most shared species. The other coffee plantation (3 km away) had the highest density of trees while the TRF had the highest bushes and seedlings density. The 50 % of the species characteristic of TRF in the área are regenerating in coffee plantations, while cultivated species showed poor or no regeneration. Conclusions: After more than 25 years of abandonment, the structure and composition of species is similar to the TRF. Abandoned shade coffee plantations contribute to natural regeneration and function as reservoirs of native germplasm for the region.