Montane Wet Forest Research Articles

Nasa ojedae (Loasaceae): A new species from the montane forests of Reserva El Corazón, western Andes of Ecuador

Nasa ojedae (Loasaceae), a new species of the Neotropical genus Nasa is here formally described from the fragmented montane wet forests of Reserva El Corazón, on the western slopes of the central Andes of Ecuador. It is one of the few, yellow-flowered, species of the Nasa grandiflora group and one of the few, coarse, biennial herbs in this otherwise shrubby or rhizomatous group. The new species is illustrated and the relationships with morphologically similar species are discussed. Based on IUCN categories and criteria, Nasa ojedae is categorized as critically endangered.

Inconsistent recovery of nitrogen cycling after feral ungulate removal across three tropical island ecosystems

Non-native ungulates (sheep, goats, and pigs) have significant negative impacts on ecosystem biodiversity, structure, and biogeochemical function throughout the Pacific Islands. Elevated nitrogen (N) availability associated with ungulate disturbance has been shown to promote the success of resource-exploitive invasive plants. While ungulate removal is a common restoration intervention, evaluations of its efficacy typically focus on vegetation responses, rather than underlying nutrient cycling. We used multiple chronosequences of ungulate exclusion (10–24 years duration) in three Hawaiian ecosystems (montane wet forest, dry forest, and dry shrubland) to determine N cycle recovery by characterizing gross mineralization and nitrification, soil inorganic N concentrations and leaching, N2O emissions, and plant tissue δ15N. Ungulate removal led to a 1–2 ‰ decline in foliar δ15N in most species, consistent with a long-term decrease in N fractionation via ecosystem N losses, or a shift in the relative turnover of N forms. This interpretation was supported by significant (dry forest) or trending (wet forest) increases in mineralization and decreases in nitrification, but conflicts with lack of observed change in inorganic N pool sizes or gaseous losses, and increased leaching in the dry forest. While results could indicate that ungulate invasions do not strongly impact N cycling in the first place (no uninvaded control sites exist in Hawai’i to test this hypothesis), this would be inconsistent with observations from other sites globally. Instead, impacts may be spatially patchy across the landscape, or ungulate invasions (possibly in combination with other disturbances) may have permanently shifted biogeochemical function or decoupled elemental cycles. We conclude that eliminating ungulate disturbance alone may not achieve restoration goals related to N cycling within the timeframe examined here.

Anthurium dairon-cardenasii, a New Species of Anthurium sect. Belolonchium (Araceae) for Colombia

A new species of Anthurium Schott (Araceae) is described, belonging to section Belolonchium (Schott) Engl. Anthurium dairon-cardenasii López-Flor., Croat & Marco Correa is dedicated in honor of the great botanist Dairon Cardenas López, who dedicated his life to the study of the Amazon. The species was recorded in Caquetá, Colombia, in a lower montane wet forest in the framework of the Caquetá BIO project.

Eriothecapaganuccii (Bombacoideae, Malvaceae), a new endangered species from montane forests in the Atlantic Forest of Bahia, northeastern Brazil.

A new species of Eriotheca (Bombacoideae, Malvaceae) from montane wet forests in the Atlantic Forest of Bahia, northeastern Brazil, is described and illustrated. It is known from only three populations situated between 750 m and 850 m in elevation on mountain summits and categorized as Endangered (EN) based on IUCN criteria. Eriothecapaganuccii is distinct from all congeners by the combination of coriaceous to strongly coriaceous leaves and remarkable few-seeded, globose to subglobose woody capsules that contain scanty kapok and the largest seeds known in the genus to date. The affinities of E.paganuccii to morphologically similar species as well as the importance of obtaining phenologically complete collections are discussed.

Feral pig (Sus scrofa) disturbance facilitates establishment of resource‐acquisitive species in Hawaiian forest understories

Abstract Invasive mammals exert pervasive effects on vegetation communities in island systems through several pathways, including by introducing novel disturbances. In Hawai‘i, feral pigs pose a particular threat to endemic species that evolved in the absence of native ungulates. The effects of pig soil disturbance on understory vegetation are contingent on the distribution and density of disturbed patches and subsequent species responses influenced by traits conferring growth and reproductive strategies. However, little is known about how these traits influence native‐ non‐native species turnover in response to pig disturbance, or how such disturbances affect trait‐mediated responses to other environmental variables. Here we quantify the effects of leaf traits and dispersal attributes on species responses to pig soil disturbance at two spatial scales—0.5 m2 patches embedded along 20 m transects within sites—across a gradient of pig density in a Hawaiian montane wet forest using Bayesian mixed models. Native and non‐native species demonstrated divergent responses, with increasing presence and abundance of non‐native species in the understory as soil disturbance within patches and sites increased. Dominant patterns in measured traits tracked the leaf economic spectrum (LES), with non‐native species tending toward resource‐acquisitive traits. Species with resource‐acquisitive traits, regardless of identity, were favoured with disturbance and responded positively to light availability in disturbed sites. Models showed species primarily dispersed by wind were more prevalent in disturbed patches and sites than those dispersed by endozoochory, while seed mass had no effect. Our results suggest pig activity influences community composition and favours non‐native species establishment, and these effects are mediated in part by traits conferring rapid resource acquisition. We also show that the extent of disturbance at the site‐scale is relevant for the influence of leaf architecture on understory responses to light availability, demonstrating how the effects of disturbance are scale‐dependent and can influence species sorting along independent environmental gradients. Read the free Plain Language Summary for this article on the Journal blog.

Rhizobiome of ‘Ōhi‘a Lehua (Metrosideros polymorpha) Offers Insight into Plant-Microbe-Invertebrate Interactions in the Subsurface

Roots are common features in basaltic lava tube caves on the island of Hawai‘i. For the past 50 years, new species of cave-adapted invertebrates, including cixiid planthoppers, crickets, thread-legged bugs, and spiders, have been discovered from root patches in lava tubes on different volcanoes and across variable climatic conditions. Assessing vegetation on the surface above lava tube passages, as well as genetic characterization of roots from within lava tubes, suggest that most roots belong to the native pioneer tree, ‘ōhi‘a lehua (Metrosideros polymorpha). Planthoppers are the primary consumers of sap at the base of the subsurface food web. However, root physicochemistry and rhizobiome microbial diversity and functional potential have received little attention. This study focuses on characterizing the ‘ōhi‘a rhizobiome, accessed from free-hanging roots inside lava tubes. Using these results, we can begin to evaluate the development and evolution of plant-microbe-invertebrate relationships. We explored lava tubes formed in flows of differing elevations and ages, from about 140 to 3000 years old, on Mauna Loa, Kīlauea, and Hualālai volcanoes on Hawai‘i Island. Invertebrate diversity was evaluated from root galleries and non-root galleries, in situ fluid physicochemistry was measured, and root and bare rock fluids (e.g., water, sap) were collected to determine major ion concentrations, as well as non-purgeable organic carbon (NPOC) and total nitrogen (TN) content. To verify root identity, DNA was extracted, and three sets of primers were used. After screening for only Metrosideros spp., the V4 region of the 16S rRNA gene was sequenced and taxonomy was assigned. Root fluids were viscous and ranged in color from clear to yellow to reddish orange. Root fluids had 2X to 10X higher major ion concentrations compared to rock water. The average root NPOC and TN concentrations were 192 mg/L and 5.2 mg/L, respectively, compared to rock water that had concentrations of 6.8 mg/L and 1.8 mg/L, respectively. Fluids from almost 300 root samples had pH values that ranged from 2.2 to 5.6 (average pH 4.63) and were lower than rock water (average pH 6.39). Root fluid pH was comparable to soil pH from montane wet forests dominated by ‘ōhi‘a (Selmants et al. 2016), which can grow in infertile soil with pH values as low as 3.6. On Hawai‘i, rain water pH averages 5.2 at sea level and systematically decreases with elevation to pH 4.3 at 2500 m (Miller and Yoshinaga 2012), but root fluid pH did not correlate with elevation, temperature, relative humidity, inorganic and organic constituents, or age of flow. Root fluid acidity is likely due to concentrated organic compounds, sourced as root exudates, and this habitat is acidic for the associated invertebrates. From 62 root samples, over 66% were identified to the genus Metrosideros. A few other identifications of roots from lava tube systems where there had been extensive clear-cutting and ranching included monkey pod tree, coconut palm, Ficus spp., and silky oak. The 16S rRNA gene sequence surveys revealed that root bacterial communities were dominated by few groups, including Burkholderiaceae, as well as Acetobacteraceae, Sphingomonadaceae, Acidobacteriaceae, Gemmataceae, Xanthobacteraceae, and Chitinophagaceae. However, most of the reads could not be classified to a specific genus, which suggested that the rhizobiome harbor novel diversity. Diversity was higher from wetter climates. The root communities were distinct from those described previously from ‘ōhi‘a flowers and leaves (Junker and Keller 2015) and lava tube rocky surfaces (Hathaway et al. 2014) where microbial groups were specifically presumed capable of heterotrophy, methanotrophy, diazotrophy, and nitrification. Less can be inferred for the rhizobiome metabolism, although most taxa are likely aerobic heterotrophs. Within the Burkholderiaceae, there were high relative abundances of sequences affiliated with the genus Paraburkholderia, which includes known plant symbionts, as well as the acidophilic genera Acidocella and Acidisoma from the Acetobacteraceae, which were retrieved predominately from caves in the oldest lava flows that also had the lowest root pH values. It is likely that the bacterial groups are capable of degrading exudates and providing nutritional substrates for invertebrate consumers that are not provided by root fluids (i.e., phloem) alone. As details about the biochemistry of ‘ōhi‘a have been missing, characterizing the rhizobiome from lava tubes will help to better understand potential plant-microbe-invertebrate interactions and ecological and evolutionary relationships through time. In particular, the microbial rhizobiome may produce compounds used by invertebrates nutritionally or that affect their behavior, and changes to the rhizobiome in response to environmental conditions may influence invertebrate interactions with the roots, which could be important to combat climate change effects or invasive species introductions.

A new species of Schlegelia (Schlegeliaceae) from wet montane forest of Colombia and a key for the species of the genus.

In this paper we describe and illustrate Schlegelialongirachis a new species from montane forest remnants (1200--1900 m) in the Western slope of the Eastern Cordillera of Colombia ("Serranía de Las Quinchas" and Virolín county) in the Departments of Boyacá and Santander. A root-climbing liana, the new species is contrasted to S.fuscata, S.monachinoi and S.parviflora, the three most morphologically similar species of Schlegelia. This new species is differentiated from its putative close relatives by vegetative (texture, colour, pubescence and shape in leaves, bracts, bracteoles pedicel, calyx and corolla), inflorescences as well as floral characters (staminode absent). We provide an updated key to 24 known species of Schlegelia. For the identification key, S.fuscata and S.roseiflora are regarded here as different from S.parviflora. S.urbaniana is considered a synonym of S.axillaris, whereas S.fastigiata is separated from S.sulphurea as a recognizable species. Schlegelia has its center of distribution in Colombia, where 17 of the species are known to occur.

A new species of Piper (Piperaceae) with peltate leaves from Serranía de las Quinchas, Colombia.

Piperquinchasense is described and illustrated as a new species occurring in the understory of wet montane forest of the middle Magdalena Valley in Colombia, the easternmost portion of the Chocó Region. Its relationships are discussed with related taxa from the Macrostachys clade. An identification key for 35 Neotropical Piper species with peltate leaves is provided.

Population Genetic Structure and Diversity of Cryptic Species of the Plant Genus Macrocarpaea (Gentianaceae) from the Tropical Andes.

The Pleistocene climatic oscillations (PCO) that provoked several cycles of glacial-interglacial periods are thought to have profoundly affected species distribution, richness and diversity around the world. While the effect of the PCO on population dynamics at temperate latitudes is well known, considerable questions remain about its impact on the biodiversity of neotropical mountains. Here, we use amplified fragment length polymorphism molecular markers (AFLPs) to investigate the phylogeography and genetic structure of 13 plant species belonging to the gentian genus Macrocarpaea (Gentianaceae) in the tropical Andes. These woody herbs, shrubs or small trees show complex and potentially reticulated relationships, including cryptic species. We show that populations of M. xerantifulva in the dry system of the Rio Marañón in northern Peru have lower levels of genetic diversity compared to other sampled species. We suggest that this is due to a recent demographic bottleneck resulting from the contraction of the montane wet forests into refugia because of the expansion of the dry system into the valley during the glacial cycles of the PCO. This may imply that the ecosystems of different valleys of the Andes might have responded differently to the PCO.

Impacts of insect frass and cadavers on soil surface litter decomposition along a tropical forest temperature gradient.

Insect herbivores play important roles in shaping many ecosystem processes, but how climate change will alter the effects of insect herbivory are poorly understood. To address this knowledge gap, we quantified for the first time how insect frass and cadavers affected leaf litter decomposition rates and nutrient release along a highly constrained 4.3°C mean annual temperature (MAT) gradient in a Hawaiian montane tropical wet forest. We constructed litterbags of standardized locally sourced leaf litter, with some amended with insect frass + cadavers to produce treatments designed to simulate ambient (Control = no amendment), moderate (Amended‐Low = 2 × Control level), or severe (Amended‐High = 11 × Control level) insect outbreak events. Multiple sets of these litterbags were deployed across the MAT gradient, with individual litterbags collected periodically over one year to assess how rising MAT altered the effects of insect deposits on litter decomposition rates and nitrogen (N) release. Increased MAT and insect inputs additively increased litter decomposition rates and N immobilization rates, with effects being stronger for Amended‐High litterbags. However, the apparent temperature sensitivity (Q 10) of litter decomposition was not clearly affected by amendments. The effects of adding insect deposits in this study operated differently than the slower litter decomposition and greater N mobilization rates often observed in experiments which use chemical fertilizers (e.g., urea, ammonium nitrate). Further research is required to understand mechanistic differences between amendment types. Potential increases in outbreak‐related herbivore deposits coupled with climate warming will accelerate litter decomposition and nutrient cycling rates with short‐term consequences for nutrient cycling and carbon storage in tropical montane wet forests.

Butterflies of Eravikulam National Park and its environs in the Western Ghats of Kerala, India

The Eravikulam National Park (ENP) holds the largest remaining pristine patches of southern montane wet temperate forests and southern montane wet temperate grasslands of peninsular India. The study shows that ENP harbours 198 species of butterflies, constituting 60.73% of the butterflies recorded from Kerala and 59.10% of butterflies observed in Western Ghats (WG). Thirty-five species of butterflies seen in ENP have some level of endemicity associated with them and 22 of them (52.38%) are strictly endemic to WG. Twenty-seven species are under the schedules of Indian Wildlife Act 1972 (WPA) and its amendments. This National Park has montane grassland-Shola dependent super-endemics like Neptis palnica and Telinga davisoni. ENP also holds Parantica nilgiriensis a Near Threatened species and another 11 Western Ghats endemics, namely, Telinga davisoni, T. oculus, Ypthima chenu, Y. ypthimoides, Arnetta mercara, Baracus hampsoni, B. subditus, Thoressa astigmata, T. evershedi, Oriens concinna, and Caltoris canaraica, which are primary grass feeders. Eravikulam, on the Anamalai–High Range–Palni landscape, lies on a major path of the return migration of butterflies to Western Ghats before the north-east monsoons. Although well-protected, the ENP has anthropogenic pressures from tea estates surrounding it, mammal-oriented management practices like controlled burning of primary grasslands, and natural forest fires, that can significantly affect the invertebrate fauna especially montane grassland shola-dependent butterflies.

Multi-Stemmed Habit in Trees Contributes Climate Resilience in Tropical Dry Forest

Understanding how environmental adaptations mediate plant and ecosystem responses becomes increasingly important under accelerating global environmental change. Multi-stemmed trees, for example, differ in form and function from single-stemmed trees and may possess physiological advantages that allow for persistence during stressful climatic events such as extended drought. Following the worst drought in Hawaii in a century, we examined patterns of stem abundance and turnover in a Hawaiian lowland dry forest (LDF) and a montane wet forest (MWF) to investigate how multi-stemmed trees might influence site persistence, and how stem abundance and turnover relate to key functional traits. We found stem abundance and multi-stemmed trees to be an important component for climate resilience within the LDF. The LDF had higher relative abundance of multi-stemmed trees, stem abundance, and mean stem abundance compared to a reference MWF. Within the LDF, multi-stemmed trees had higher relative stem abundance (i.e., percent composition of stems to the total number of stems in the LDF) and higher estimated aboveground carbon than single-stemmed trees. Stem abundance varied among species and tree size classes. Stem turnover (i.e., change in stem abundance between five-year censuses) varied among species and tree size classes and species mean stem turnover was correlated with mean species stem abundance per tree. At the plot level, stem abundance per tree is also a predictor of survival, though mortality did not differ between multiple- and single-stemmed trees. Lastly, species with higher mean stem abundance per tree tended to have traits associated with a higher light-saturated photosynthetic rate, suggesting greater productivity in periods with higher water supply. Identifying the traits that allow species and forest communities to persist in dry environments or respond to disturbance is useful for forecasting ecological climate resilience or potential for restoration in tropical dry forests.

A new species of Andean mouse of the genus Thomasomys (Cricetidae, Sigmodontinae) from the eastern Andes of Ecuador

We name and describe a new species of Andean mouse from the eastern slope of the Andes of central Ecuador (Sangay National Park). This rodent is large-bodied (head-body length 167–184 mm) inhabiting the wet montane forest between 3,400–3,900 m in elevation. A molecular phylogeny based on mitochondrial genes resolved the new species as a member of the “aureus” group, closely related to an undescribed species from north Ecuador. This finding increases the diversity of Thomasomys to 48 species, of which 18 species inhabit Ecuador. In addition, the species described herein is the largest species of the genus described in Ecuador.

Annotated checklist of the vascular plants of Mount Kenya, East Africa

Mount Kenya, with its rich plant diversity, is among the famous tropical mountains in the world, and is the second highest mountain in Africa after Mount Kilimanjaro. An annotated checklist of the vascular plants of Mount Kenya was compiled through several approaches including our own collections from 2009 to 2018. A total of 1 545 vascular plants are found on Mount Kenya, including 1 481 indigenous and 64 exotics. The indigenous species are represented by nine lycophytes (five genera, two families), 129 ferns (56 genera, 20 families), three gymnosperms (three genera, two families), and 1 340 angiosperms (624 genera, 132 families). Trees constitute 9.92% of the flora, shrubs 15.99%, lianas 3.10%, climbers 4.45%, herbs 57.22%, lycophytes 0.61%, and ferns 8.70%. The two types of forest vegetation (lower montane wet forest and lower montane dry forest) have the highest and nival zone have the lowest species richness. In total, 18.96% of the species are distributed in Africa and other continents, 60.26% are endemic to Africa, 12.17% are endemic to Tropical East Africa, 3.17% are endemic to Kenya, 1.29% are endemic to Mount Kenya, and 4.14% are exotic plants. These results provide foundational data for further studies, and also provided support for the local government to formulate conservation policies.

Coarse woody debris density and carbon concentration by decay classes in mixed montane wet tropical forests

AbstractThe role of coarse woody debris (CWD) in the global carbon (C) cycle is growing under increasing tree mortality driven by climate variability and disturbances. Quantifying C in CWD critically depends on accurate estimates of CWD density and C concentration in CWD. This study considered the main decomposition pathways (the proportions of CWD decomposed by fungi vs. invertebrates; fungal decay types) and the relationships between decay class, wood density, moisture, and C content of CWD in old‐growth mixed monsoon montane tropical forests in Vietnam based on the inventory of 359 CWD pieces. The bulk density of wood of the 1st, 2nd, 3rd, 4th, and 5th decay classes averaged 0.56, 0.49, 0.37, 0.28, and 0.15 g cm−3, respectively. The density reduction across decay classes did not significantly differ for snags, stumps, branches, leaning, and lying logs. Wood density was negatively related to wood moisture. The wood mass loss averaged 0%, 20%, 37%, 54%, and 74% in the CWD of the 1st, 2nd, 3rd, 4th, and 5th decay classes, respectively. Signs of invertebrate activity were recorded on 3% of CWD pieces. Among CWD samples with identifiable decay type, 88% were decomposed by white‐rot, 8% were decomposed as brown‐rot, and 4% of pieces contained both white‐ and brown‐rot patches. The mean C concentration in wood was 46.5%. It did not change with decay class. Our research provides an empirical basis for future inventories of CWD carbon stocks in Asian montane tropical mixed forests.

Site fidelity and other attributes of infrequently trapped bats over two decades in a montane wet sclerophyll forest

A long-term perspective on bat populations is lacking in most ecosystems. We describe fluctuations in capture rate, sex ratio, body condition, site fidelity and longevity of banded bats over two decades as part of an annual banding study in a montane forest. We focus on five species previously omitted from mark–recapture analyses because band returns were too low. Each species was infrequently trapped and/or retrapped, though this was often highly variable. A degree of site fidelity was recorded for all species, even those where trap success was low. We recorded maximum longevity (likely an underestimate) of at least 5 years for eastern falsistrelle Falsistrellus tasmaniensis and 7 years for Gould’s long-eared bat Nyctophilus gouldi and golden-tipped bat Phoniscus papuensis. Although N. gouldi was assumed to be highly detectable in harp traps, recaptures were few and none were retrapped more than once. No female greater-broad-nosed bat Scoteanax rueppellii were captured, a minor male bias was evident for F. tasmaniensis and sex ratios were close to parity for N. gouldi, P. papuensis and eastern horseshoe bat Rhinolophus megaphyllus. Body condition and mass were mostly stable over the study and were not related to periods of drought (except perhaps F. tasmaniensis in 2019) or higher rainfall. Although we recorded some degree of site fidelity among years, the extent of any seasonal or nomadic movements remains largely unknown.

Nest Site Characteristics of Two Endangered Seabirds in Montane Wet Forests on the Island of Kaua‘i, Hawai‘i, USA

The nest site characteristics of two endangered seabird species–the Hawaiian Petrel Pterodroma sandwichensis and Newell's Shearwater Puffinus newelli–on Kaua‘i were considered. Burrows of both species were predominantly found under tree roots or small caves on steep slopes and were associated with native plants, both in the canopy (particularly Metrosideros polymorpha) and the understory (particularly Dicranopteris linearis). There were, however, marked differences between the two species. Hawaiian Petrels were found at higher elevations with a shorter, patchy canopy and more open understory. Models using microhabitat variables were better able to classify burrows than those using landscape topographic metrics, suggesting that metrics describing the immediate area around the burrow are more important to burrow selection. A comparative model indicated that elevation and maximum vegetation height were the strongest variables in classifying between the two species. Understanding microhabitat needs for these species is important for locating new colonies and for the successful implementation of management actions such as colony creation through social attraction. Furthermore, with the spread of Rapid’Ōhi’a Death canker disease Ceratocystis huliohia on Kaua‘i, the heavy reliance by both species on forest dominated by M. polymorpha (the tree killed by this disease) should be of increasing consideration for conservation efforts targeting these species.

Hawaiian Paratachys Casey (Coleoptera, Carabidae): small beetles of sodden summits, stony streams, and stygian voids.

Five Hawaiian species of Paratachys Casey are revised, including four newly described: Paratachys terryli from Kauai; P. perkinsi from Moloka‘i; P. haleakalae from Maui; and P. aaa from Hawai‘i Island. A lectotype is designated for the fifth Hawaiian species currently combined with Paratachys, Tachys arcanicola Blackburn, 1878 of Oahu. Hawaiian Paratachys spp. known from more than one specimen exhibit some degree of ocular polymorphism, that variation being extreme in P. terryli where individuals range in ocular development from macrophthalmic with broadly convex eyes to microphthalmic with small, flat eyes. All Hawaiian Paratachys species comprise individuals with vestigial wings, with the exception of P. terryli, where a single macropterous, macrophthalmic female complements the other 18 brachypterous specimens. Based on a transformation series of characters from the male aedeagus, the biogeographic history of Hawaiian Paratachys is consistent with progressive colonization of the Hawaiian Island chain. Three of the species do not appear to represent species of conservation concern, with P. terryli and P. haleakalae known from terrestrial deep soil, litter, and streamside microhabitats in montane wet rain forest, and the troglobitic P. aaa occupying the dark zone of numerous, recently developed lava tube caves within the Mauna Loa and Kilauea volcanic massifs. The conservation status of the other two species is much more dire, with P. arcanicola of O‘ahu not seen in nature since the early 20th Century, and P. perkinsi known only from a single specimen fortuitously collected in 1894 near sea level on Moloka‘i.

Interannual variation in rainfall modulates temperature sensitivity of carbon allocation and flux in a tropical montane wet forest.

Tropical forests exert a disproportionately large influence on terrestrial carbon (C) balance but projecting the effects of climate change on C cycling in tropical forests remains uncertain. Reducing this uncertainty requires improved quantification of the independent and interactive effects of variable and changing temperature and precipitation regimes on C inputs to, cycling within and loss from tropical forests. Here, we quantified aboveground litterfall and soil-surface CO2 efflux ("soil respiration"; FS ) in nine plots organized across a highly constrained 5.2°C mean annual temperature (MAT) gradient in tropical montane wet forest. We used five consecutive years of these measurements, during which annual rainfall (AR) steadily increased, in order to: (a) estimate total belowground C flux (TBCF); (b) examine how interannual variation in AR alters the apparent temperature dependency (Q10 ) of above- and belowground C fluxes; and (c) quantify stand-level C allocation responses to MAT and AR. Averaged across all years, FS , litterfall, and TBCF increased positively and linearly with MAT, which accounted for 49, 47, and 46% of flux rate variation, respectively. Rising AR lowered TBCF and FS , but increased litterfall, with patterns representing interacting responses to declining light. The Q10 of FS , litterfall, and TBCF all decreased with increasing AR, with peak sensitivity to MAT in the driest year and lowest sensitivity in the wettest. These findings support the conclusion that for this tropical montane wet forest, variations in light, water, and nutrient availability interact to strongly influence productivity (litterfall+TBCF), the sensitivity of above- and belowground C fluxes to rising MAT (Q10 of FS , litterfall, and TBCF), and C allocation patterns (TBCF:[litterfall+TBCF]).

Redescription of the snake Lachesis melanocephala (Squamata: Viperidae): Designation of a neotype, natural history, and conservation status

Introduction: The Black-headed Bushmaster (Lachesis melanocephala) is a large venomous snake that inhabits tropical moist forest, wet forest, montane and premontane wet forest in Southwestern Costa Rica and extreme Western Panama. Objective: We assign a neotype for the species due to the loss of the original holotype and update the information on its geographical distribution, natural history, and conservation status. Methods: To determine the conservation status of L. melanocephala, we modeled its potential distribution using the species` locality records and distribution modeling analysis implemented in MaxEnt. Based on the species’ potential distribution, we evaluate the loss of its original habitat and estimate the percentage of its distribution area that is currently protected by the country’s protected area system. Results: The potential distribution of the species was estimated at 10 139 km2, including areas where the species currently occurs and historical areas where the species has been registered but is nowadays considered locally extinct. About 29 % of that potential distribution overlaps with protected wild areas, so less than a third of the potential distribution of the species is under protection. Conclusions: During the last decade, accelerated habitat loss and growing evidence of declining natural populations indicate the need for urgent protective measures to prevent the extinction of this species in the foreseeable future.