This study evaluated the methane (CH4) production capacity of microbial consortia from three neotropical lakes at different altitudes: Mojanda (4,263 m.a.s.l., 10°C), Papallacta (3,250 m.a.s.l., 14°C), and Caimanes (510 m.a.s.l., 25°C). Specific methanogenic activity (SMA) and biochemical methane potential (BMP) from cellulose were assessed at two temperatures (the original lake temperature and 37°C) and three different inoculum-to-substrate ratios (ISR of 1, 2, and 4). The highest SMA values were observed at 37°C, being 0.021, 0.011, and 0.009 g COD/gVS·d for Caimanes, Papallacta, and Mojanda, respectively. At their original temperatures, only Mojanda and Caimanes showed activity (0.007 and 0.014 COD/gVS·d), which was significantly lower. Methane yields from cellulose were also highly temperature-dependent. The highest yield was achieved by the Caimanes consortium at 37°C (409 NmL CH4/gVS), while at its native 25°C, the yield was 147 NmL CH4/g VS. The Mojanda consortium, from the highest altitude, produced methane even at 10°C (26 NmL CH4/gVS), while at 37°C was 137 NmL CH4/gVS. No activity was detected for Papallacta at its original temperature (14°C) but 203 NmL CH4/gVS for 37°C. These results demonstrate the strong temperature dependence of these consortia and classify them as psychrotrophic rather than psychrophilic. This sensitivity suggests a potential for increased greenhouse gas emissions from these lakes under climate warming scenarios. Furthermore, the resilience and cellulolytic activity at low temperatures exhibited by these consortia highlight their potential for specialized applications in anaerobic digestion, such as bioaugmentation for the treatment of complex wastes.
The Sierra Norte of Oaxaca, M & eacute;xico, because of its high biodiversity, is a good candidate for studying the possible effects of climate change on its flora distribution. Currently, several modelling tools have been developed to facilitate the prediction of present and future species distribution. The objective of this study is to evaluate the impact of climate change on the distribution of four locally important medicinal plant species from the Asteraceae family (Heterotheca inuloides, Laennecia filaginoides, Pinaropappus roseus, and Tagetes lucida). The analysis was done using the maximum entropy algorithm under three different time periods: the present, 2050, and 2070, projected to the Representative Concentration Pathways (RCP 4.5 and RCP 8.5) future climate scenarios. Using a principal component analysis, we selected the variables that best explained each of the models. The modelling results showed that it is difficult to identify a consistent pattern of species distribution under the different scenarios and time periods since the species responses differed among time periods and scenarios. Laennecia filaginoides is the only species whose distribution increases by 2050 and 2070 under both scenarios analyzed. Our results may support future conservation strategies in the communities where species are distributed and utilized due to their demonstrated capacity to alleviate different illnesses.
The concept of a "community" as a form of organization for natural biological systems is both widespread and widely accepted within the ecological and biological sciences. Communities have been defined as groups of organisms that interact in ways that denote interdependence between individuals and taxa (e.g. as defined by "food webs") but they have also been defined as groups of co-occurring organisms that are assumed to interact by virtue of their shared spatiotemporal existence. The latter definition has been debated and challenged in the literature, with mounting evidence for co-occurrence being more indicative of coincident ecological niches in space and time rather than being evidence of ecological interaction or dependency. Using a dataset of 460 Costa Rican bird species divided into breeding and non-breeding season datasets, we empirically demonstrate the ways in which co-occurrence can create illusory communities based on similar occupied ecological niches and similar patterns of co-occurrence at different times of year. We discuss the importance of discerning coincidental co-occurrence from true ecological interactions that would manifest a true community, and further address the importance of differentiating communities of co-occurrence from communities of demonstrable ecological interaction. While co-occurrence is a necessary aspect of interspecific interactions, we discuss and demonstrate here that such co-occurrence does not make a community, nor should explicit patterns of co-occurrence be seen as evidence for evolutionarily important ecological interactions.
ABSTRACTAnimals endemic to tropical mountains are known to be especially vulnerable to climate change. The Cordillera de Talamanca (Costa Rica and Panama) is a geographically isolated mountain chain and global biodiversity hotspot, home to more than 50 endemic bird species. We used eBird community science observations to predict the distributions of a suite of 48 of these endemic birds in 2006-2015, and in 2070, under four climate change scenarios. Species distributions were predicted using program Maxent, incorporating elevation, satellite derived habitat data, and WorldClim climate variables. Model fit, as assessed by Area under the Receiver Operator Curve (AUC) was very high for most species, ranging from 0.877 to 0.992 (mean of 0.94). We found that most species are predicted to undergo range contractions by 2070, with a mean of 15% under modest climate change (RCP 2.6) up to a mean of 40% under more severe climate change (RCP 8.5). Most of the current ranges of these species are within existing protected areas (average of 59% in 2006-2015), and with prospective range contractions, the importance of these protected areas is forecast to increase. We suggest that these predicted range declines should elevate conservation concerns for this suite of species, and vigilance, in the form of better population monitoring, is urgently needed.
Plant survival in semi-arid climates depends on morphological, anatomical, and physiological adjustments that determine survival under limiting environmental conditions. In this study, anatomical and morphological characteristics of three herbaceous species with different growth habits were determined: a tall herb, Mesosphaerum suaveolens (tall), Stachytarpheta sanguinea (short), and Jacquemontia evolvuloides (climbing). Fully expanded leaves were collected from three sites in each of three different natural regeneration periods in a seasonally dry tropical forest. Leaf, specific leaf area, epidermis, cuticle, parenchyma, and mesophyll thicknesses; stomatal and trichome densities were measured. All three species have stomata and trichomes on both leaf surfaces and higher densities on the abaxial surface than the adaxial surface. M. suaveolens and S. sanguinea have unusual leaf morphological and anatomical adjustments, with a larger leaf area in the more open and youngest site, but thicker abaxial and adaxial epidermis and mesophyll in the oldest site which has the closest canopy stratum. J. evolvuloides has more usual adjustments, with a smaller specific leaf area and thinner epidermis and isobilateral parenchyma in the youngest site, being better acclimatized to low water availability and high light incidence. Therefore, M. suaveolens and S. sanguinea have unique acclimatization strategies for different environmental conditions.
Most of the species of the genus Philornis are obligate parasites of birds' nests, especially affecting small populations. However, research on factors influencing its distribution is scarce. This study focuses on analyzing some elements that facilitate the parasitism of this genus on several species of birds in continental Ecuador. From a sample obtained over two years (2019-2020) in five different locations on the country's coast, 693 nests of land birds and raptors were analyzed. Of these, 13% were parasitized. Two Philornis species already reported for Ecuador (Philornis downsi, P. niger) and two morphotypes not previously registered in the country were recorded, preliminarily classified as P. sp. nr. bellus and P. sp. nr. falsificus. The species with the highest proportion was P. downsi, both in terms of nest prevalence and intensity. Each species of the parasite showed an affinity for one or more families of birds and it was evidenced that the shape of the nest facilitates the prevalence of Philornis. The prevalence of Philornis decreases in higher places in the dry coastal forests. The probability of infection was also influenced by habitat alteration: nests from disturbed sites have a higher prevalence of parasites than nests with natural forest (P = 0.002). The present study strengthens the existing knowledge about different environmental factors that influence Philornis parasitism birds of continental Ecuador.
ABSTRACTMost of the species of the genus Philornis are obligate parasites of birds’ nests, especially affecting small populations. However, research on factors influencing its distribution is scarce. This study focuses on analyzing some elements that facilitate the parasitism of this genus on several species of birds in continental Ecuador. From a sample obtained over two years (2019-2020) in five different locations on the country’s coast, 693 nests of land birds and raptors were analyzed. Of these, 13% were parasitized. Two Philornis species already reported for Ecuador (Philornis downsi, P. niger) and two morphotypes not previously registered in the country were recorded, preliminarily classified as P. sp. nr. bellus and P. sp. nr. falsificus. The species with the highest proportion was P. downsi, both in terms of nest prevalence and intensity. Each species of the parasite showed an affinity for one or more families of birds and it was evidenced that the shape of the nest facilitates the prevalence of Philornis. The prevalence of Philornis decreases in higher places in the dry coastal forests. The probability of infection was also influenced by habitat alteration: nests from disturbed sites have a higher prevalence of parasites than nests with natural forest (P = 0.002). The present study strengthens the existing knowledge about different environmental factors that influence Philornis parasitism birds of continental Ecuador.
Seasonally dry tropical forests are ecosystems of high endemism and floristic diversity, but they have been relatively not well-studied ecosystems and are very much threatened by anthropic pressures. This study aimed to evaluate the dendrometric and horizontal structure characteristics of the population of 12 endemic plant species in the semideciduous forest of the Equatorial Pacific Coastal Cordillera of the Machalilla National Park, Manabi, Ecuador. This is one of the most extensive protected areas on the Ecuadorian coast, located in the Tumbes-Choco-Magdalena biogeographic region. It is considered one of the 25 hotspots worldwide. We selected 12 species that hypothetically co-exist in this semideciduous forest (Bursera graveolens, Eriotheca ruizii, Handroanthus chrysanthus, Ziziphus thyrsiflora, Geoffroea spinosa, Myroxylon balsamum, Priogymnanthus apertus, Melicoccus bijugatus, Nectandra reticulata, Simira ecuadorensis, Coccoloba ruiziana, Klarobelia lucida). We studied five 2500 m2 transects, where dendrometric variables (tree height, diameter at breast height-DBH, basal area, altimetric and diameter classes) were evaluated. We evaluated the horizontal structure variables of populations like absolute/relative abundance, dominance and frequency, and the importance value index (IVI and IVN). In 12,500 m2, the results identified 331 individuals. M. balsamum was the highest species (9.41 m), while E. ruizii had the highest DBH (21.03 cm) and the biggest basal area (0.05 m2). The species with the highest absolute/relative abundance and frequency were S. ecuadorensis and H. chrysanthus, and the latter had the highest absolute dominance (1.23 m2 center dot ha-1). S. ecuadorensis presented the highest importance value index based on 100 and 300, followed by H. chrysanthus and Z. thyrsiflora. P. apertus, M. balsamum, E. ruizii and C. ruiziana obtained intermediate values. The least ecological weight was for N. reticulata, K. lucida, M. bijugatus and G. spinosa. No B. graveolens individuals were observed in the studied transects in this forest because this species was found at altitudes < 240 m a.s.l. The results of the altimetric and diameter classes indicated that the studied sector corresponds to a relatively young secondary forest affected by natural and anthropic factors.
Traditional knowledge, much like scientific knowledge, is the product of observation and reflection from the relationship between people and their habitat. This paper documents the first inventory of native names and ethnozoological information of snakes in the language of the Shiwiar-Chicham (SC) and Kichwa (KW), for those territories located in the Pastaza and Napo basins, Amazonia of Ecuador. Additionally, we analyzed the diversity of native names with the Shannon-Wiener index (D). A total of 50 snake species are inventoried, where 36 species (80%) and 49 (100%) snakes possessed a name in the SC and KW languages, respectively. The KW language (D = 4.02) presented a greater diversity of names assigned to snakes, in comparison to the SC language (D = 3.04). The great cultural and linguistic diversity demonstrates that there is still a need to document and safeguard the ethnozoological knowledge related to snakes in the Amazon.
We report the first cases of leucism in Ceratophrys stolzmanni larvae. The leucistic individuals were recorded in an ex-situ population for conservation and research of the species, within the Conservation Initiative for Threatened Amphibians "Balsa de los Sapos" [Raft for Frogs] at the Pontificia Universidad Catolica del Ecuador. These individuals presented different color traits from those of the same cohort and as they grew older their uniform white coloration was defined. The leucistic individuals died as tadpoles, after time periods that exceeded the ones reported and recorded for ending metamorphosis in the species, suggesting a link between the absence of pigmentation and a potential malfunction of the thyroid gland.
Understanding the reproductive biology of birds is crucial for comprehending their natural history and implementing effective conservation practices. However, there is limited information available on the reproductive behavior of many bird species in Southern Ecuador. This manuscript contributes to the knowledge of the reproductive biology of 127 bird species from the region, providing detailed information on five species whose reproductive traits were previously undocumented (Urochroa leucura, Agriornis albicauda, Turdus maranonicus, Spinus olivaceus, and Stilpnia viridicollis), as well as reproductive data on 12 species for which information was scarce (Heliangelus viola, Chalcostigma stanleyi, Eriocnemis luciani, Coeligena iris, Megascops koepckeae, Conopophaga castaneiceps, Sclerurus obscurior, Leptasthenura andicola, Ochthoeca fumicolor, Geospizopsis unicolor, Catamenia inornata, and Sporophila castaneiventris). Furthermore, we include additional information on the reproductive biology of 110 species that have already been documented. This manuscript provides the most up-to-date inventory of the reproductive behavior of bird species in Southern Ecuador, which can aid in the development of better conservation strategies in the region.
The Trinidadian red-brocket deer (Mazama americana trinitatis) is the only species of deer in Trinidad and is classified as a unique subspecies of red-brocket deer. Despite the importance of the species in Trinidad, to date there have been no published studies on their densities. We report on the densities of this species at four different sites in Trinidad over a 3-year period, with the first 2 years sampled during a hunting moratorium. Diurnal surveys were conducted, with density estimates calculated using King's Estimator. Surveys were repeated in both the dry and rainy seasons. A total of 312 deer on 1131.4 km of transect were observed over the study. Density estimates varied between different sites (1-16 individuals/km(2)), and between one and eight individuals/km(2) island-wide. Overall, the estimated density of red-brocket deer increased in two of four sites during the study period, indicating that the institution of the moratorium may have had a positive impact on populations of deer. The fact that density estimates varied considerably across the island suggests that harvest levels may need to be tailored for different sites.
The elusive Greater Grison has been reported to predate mostly relatively small prey, with evidence of some larger items. Using observations from cell phones and social media, I report two separate predation events by Grison (Galictis vittata) upon its largest known prey to date, the Paca (Cuniculus paca); both events in Costa Rica. These observations of Paca, a nocturnal cavity dwelling rodent, being predated upon diurnally, suggest that Grison target the burrows of such species as a hunting strategy.
In Brazil, the number of animals killed by vehicle collision surpasses 475 millions/year, but the actual number may be even higher since roadkill data in the country is scarce and punctual. Using a standard protocol, the project Caminhos da Fauna monitored since 2006 the avifauna roadkill in the BR-040 (RJ/MG) highway, southeastern Brazil. Here, we present a checklist of the avifauna registered during the 10-year monitoring program, including the list of roadkills, indicating threatening status at regional, national, and global levels, and the number of records/species. We registered 1,317 individuals belonging to 180 species, 21 orders, and 48 families. Another 247 individuals could not be identified. For seven families roadkills were higher than 50 individuals: Thraupidae, Cuculidae, Strigidae, Tyrannidae, Psittacidae, Columbidae, and Turdidae. The most collected species were Crotophaga ani (n = 106; Cuculidae), followed by Psittacara leucophthalmus (n = 61; Psittacidae), Piaya cayana (n = 56; Cuculidae), and Asio clamator (n = 44; Strigidae). Five species were under threat: Penelope obscura, Primolius maracana, Pteroglossus bailloni, Ramphastos vitellinus, and Sicalis flaveola. Most species were geographically widespread, while other 13 (7.2%) were endemic. Given the considerable amount of data obtained, further efforts of the same motivation in other Brazilian roads and express transportation systems should be encouraged.
Nightjars (Family Caprimulgidae) are insectivorous birds with crepuscular and nocturnal habits. Their coloration and cryptic behavior make this group extremely difficult to register, being more easily heard than sighted. The rufous nightjar (Antrostomus rufus) is a widely distributed species from Southern Central America to Northern Argentina, but most aspects of its life history remain unknown. By the employment of an acoustic remote unit, we evaluated the vocal activity and environmental variables of vocalizations by rufous nightjars during a complete annual cycle at one site in the Yungas Andean Forests of Northwestern Argentina. The results, based on one sampled site, indicate that the vocal activity of this species is performed during the breeding season (between September and November). During these months, this species showed a peak of vocal activity at midnight (between 00:00 and 01:00 hs) and at dawn (06:00 hs). In addition, most vocalizations were recorded during full moon nights, and temperature was negatively related to the vocal activity. We highlight the importance of using passive acoustic monitoring as a tool for understanding the life history of nocturnal neotropical birds.
ABSTRACTClimatic seasons have been shown to determine the temporal fluctuations in species communities of different ecosystems. Here, we assessed the diversity of spider assemblages in dry, transition and rainy seasons in the “Guillermo Piñeres” Botanical Garden (GPBG), Turbaco, Colombia. We collected spider assemblages between June 2018 and April 2019 through standardized day and night sampling methods for tropical ecosystems: looking up, looking down, beating and leaf litter sieving. In total, we collected 1585 individuals, belonging to 28 families and 112 (morpho) species. We calculated the effective species richness (Hill numbers) to evaluate the changes in diversity across seasons and used clustering and ordination methods (Jaccard index-based nMDS) to identify differences in the composition of the assemblages. Also, we compared the abundance and species richness of predatory guilds of the three seasons. The transition season showed the highest diversity with 94 morphospecies, an effective number of species of 48.7 and a dominance of 32.4 effective species. The clustering and ordination methods grouped the sampling events into three groups, each corresponding to a climatic season. The most abundant guild was the orb web weavers, with the highest value in the rainy season, while “other hunters” were the most species rich. Our results indicate that the spider assemblages in GPBG present a seasonal variation in diversity, probably influenced by climatic conditions. Understanding how these seasonal changes occur is necessary to develop forest management strategies for monitoring and management projects on the conservation of species assemblages according to the Convention on Biological Diversity.
Owls (Strigiformes) play an important ecological role as predators that structure and organize biological communities. Specialized owl species dependent on old-growth forests have suffered declines because of forest loss or degradation by human activities. Few studies have been conducted on Neotropical owls, especially in the Piedmont Forest of Northwestern Argentina. The scarcity of information on habitat requirements and the effect of human impacts preclude the establishment of conservation and management activities. The human footprint index (HFI) is a tool for mapping human impacts on biodiversity that is used at global and regional scales, based on the estimated and standardized contribution of different human impact variables (e.g. road networks, urban centers, agricultural land, etc.). The objectives of this work were to: 1) Determine the call rate of five owl species in the Piedmont Forest of Northwestern Argentina, 2) relate forest structure to the call rate of owl species, and 3) relate human footprint index to the call rate of owls. We placed 28 automatic recorders in the Piedmont Forest, in sites with low and high Human influence, and characterized the forest structure around each recorder within a circular plot of 25 m diameter. We obtained 241 vocalizations in 168 intervals of 2 h for Ferruginous pygmy owl (Glaucidium brasilianum), Tropical screech-owl (Megascops choliba), Black-banded owl (Ciccaba huhula), Spectacled owl (Pulsatrix perspicillata), and Buff-fronted owl (Aegolius harrisii). We found that for Tropical screech-owl live tree basal area had a positive and diameter at breast height standard deviation had a negative influence on call rate. While for Black-banded owl, the dead tree density had a positive and human footprint index >1 had a negative influence on call rate. For Spectacled owl, dead tree density and human footprint index >1 had a negative influence on call rate. We provide first insights into the effects of forest structure and human influence on the call rate of owls in the Piedmont Forest of Northwestern Argentina, information that may guide forest management guidelines and conservation strategies.
ABSTRACTThere is a need for robust methodological approaches to improve our capacity to automatically detect plant species from seed samples tohelp support plant management strategies. In this study, we tested different neural network techniques to automatically detect native species from seeds from the Andean páramo region based on optic RGB images. Specifically, we compared i) simple feed-forward networks (SNNs), consisting of feed-forward nets with error back-propagation, holding one hidden layer with different number of neurons; and ii) deep convolutional neural networks (CNNs), which have their convolutional layers-built form multiple 3x3 kernels. First, we sampled 50 seeds from four common plant species in the La Rusia Páramo (Colombia): Espeletia congestiflora, Bucquetia glutinosa, Calamagrostis effusa and Puya santosii. We took RGB images of individual seeds for each species on contrasted white and black backgrounds, and then classified all images under both SNNs and CNNs. Under a double cross-validation scheme, the SNN approach with 14 neurons approached 88% of test accuracy, while CNN achieved 93%. Moreover, when increasing the image sample in the training dataset fed to models, CNN performed with 100% accuracy when used on testing and validation datasets. Overall, the neural network approach explored here suggests a promising methodology for species prediction from seeds based on optical RGB images, with potential for automatic seed recognition and counting on the field.
Domestic cats (Felis catus Linnaeus, 1758) can interact with and cause several negative impacts upon wildlife if unconstrained by their owners. These impacts occur especially because of their innate predatory behavior and, usually the lack of any natural predators, as well as due to their high abundances relative to native carnivores. Although these impacts are well studied in temperate countries, there are but a few records of species used as prey by these carnivores in Brazil. Here, we expand the knowledge of native species preyed upon by domestic cats in Brazil by presenting new records of this predator-prey interaction and reviewing records in the literature. Predation events were recorded through opportunistic encounters between 2016 and 2022. We recorded the predation of 14 native terrestrial vertebrate species (reptiles, amphibians, birds, and mammals) from the Cerrado and Atlantic Forest biomes. Our literature review recovered predation events by cats in the two aforementioned biomes plus in the Amazonia. Our results increase to 48 the number of wild species preyed upon by domestic cats in Brazil, which is probably an underestimation, as this number is much higher in other countries of comparable land size and species diversity. We suggest that cat population control measures should be carried out, especially in protected areas.
Telmatometra withei (Bergroth, 1908) is a common water strider found across the Neotropics. Although, the taxonomy of T. withei is relatively well known, the specie’s life cycle has not been characterized. We use field surveys and laboratory experiments to describe the life cycle of two populations of T. withei in the Pacific coast of Panama. Specifically, we compared the life cycle between fresh and brackish water populations known to show local adaptation to each environment. We also contrast the life cycle of T. withei with that of other water striders previously reported in the literature. We found that the average life cycle of T. withei is approximately 66.7 days, and this period did not vary significantly between fresh (65.0 days) and brackish (68.3 days) populations. However, these estimates were longer than those reported for other species of water strides. In addition, traits associated with reproductive success such as egg length and fecundity varied significantly between populations, with females from freshwater populations showing larger values. This suggests that salinity can have important consequences for reproductive traits in T. withei, even if the overall life cycle may not be affected by salinity. Thus, characterizing the life history of these Neotropical organisms is crucial to understand the rich freshwater biodiversity of this region, as well as its response to both natural and anthropogenic disturbances.
