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Background: Lycianthes moziniana (Capsiceae, Solanaceae) is an endemic and widespread species in Mexico. Morphological and molecular evidence suggested three varieties (L. moziniana var. margaretiana, L. moziniana var. moziniana and L. moziniana var. oaxacana). Hypotheses: Lycianthes moziniana is integrated by differentiated lineages corresponding to the three varieties identified. Studied species: Lycianthes moziniana (Dunal) Bitter. Study sites and dates: Mexico from 2017 to 2021. Methods: We measured 11 morphological characters based on 207 herbarium specimens. Discriminant Canonical Analysis (DCA), Mahalanobis Square Distance (MD) and Canonical Classificatory Analysis (CCA) were used to uncover the differences among varieties. For geographic and climatic preferences and divergence, we used 288 records and four climatic layers. Results: Two canonical functions explained 100 % of the morphological variation and seven characters had the highest discriminatory power. In addition, MD was statistically significant. Meanwhile, the CCA recovered three groups at 77 %. The morphological evidence demonstrated the distinctiveness of L. moziniana var. moziniana. In contrast, L. moziniana var. margaretiana and L. moziniana var. oaxacana were morphologically similar. The identity test showed significant differences among Ecological Niche Models (ENMs). The evidence indicates geographic and climatic isolation among the varieties. Lycianthes moziniana var. moziniana is widespread and has intermediate overlap with the other two varieties. Lycianthes moziniana var. margaretiana and L. moziniana var. oaxacana were isolated in different biogeographical provinces and showed the lowest overlap. Conclusions: Morphological and geographic data indicates incipient speciation is occurring.

Neotropical savannas have undergone continuous processes of landscape transformation (e.g., agriculture, oil, gas, and hydrocarbon industry) and very little is known about the ecology and natural history of key biological groups such as terrestrial mammals while the information on behavioral aspects of mammalian species in these ecosystems is very scarce. Here, we aimed to describe the activity patterns of medium and large mammals in two savanna ecosystems in the Colombian Llanos. A set of 60 camera traps was installed in the two ecosystems for 35 days (2100 camera days). We described the activity patterns of nine predominantly nocturnal species. We found no difference in circadian distributions of mammals between ecosystems. Cuniculus paca Linnaeus 1758 and Dasyprocta fuliginosa Wagler 1832 showed patterns of exclusion probably due to competition whereas other species like Tamandua tetradactyla Linnaeus1758 and Myrmecophaga tridactyla Linnaeus 1758 displayed similar activity patterns. We highlight the importance of savannas for the conservation of these species and discuss the relevance of studies on activity patterns for mammal ecology and conservation in Neotropical savannas.

Background: Zelkova schneideriana Hand.-Mazz., is an endangered species mainly distributed in subtropical China. Currently, little is known about its niche and interspecific association. Questions: What are the niche characteristics of Z. schneideriana and other associated species? What are the interspecific associations between these species? Study sites and dates: Z. schneideriana communities in Jiangsu, China in 2019. Methods: Twenty-one 400 m2 plots were studied for importance value, niche breadth and overlap, interspecific association of Z. schneideriana communities. Results: In 39 species of tree layer, Z. schneideriana had the greatest importance value and niche breadth. For the first 10 dominant species, a considerable difference was detected by the Levins index (1.75 - 19.84) and Shannon-Wiener index (0.77 - 3.02). Forty-four out of the 45 species pairs had the value of niche similarity indices ≤ 0.5; 38 species pairs had the value of niche overlap indices ≤ 0.5. Overall interspecific association was not a significantly negative association for variance ratio < 1. χ2 test and Spearman’s correlation coefficient further revealed that above 60 % of species pairs had negative associations, suggesting most dominant species were slightly associated with other species or even independent. Conclusions: Z. schneideriana was a constructive species. Dissimilarity in environmental requirements was found among most dominant tree species, thus decreasing competition. This is likely due to the unstable community in the early stage of succession.

Abstract: The objective of this work was to estimate an index of the relative biomass per species, in a medium to large-sized mammal community, as well as to determine how the introduced wild boar (Sus scrofa) fits into this index, and to verify if the occupancy of sites by domestic dogs interferes with those of wild boars and how much the periods of dogs’ activity overlap those of wild boars. The biomass/effort index was measured for each native mammal species and for the introduced wild boar, in two surveyed farms in Brazil’s Western Atlantic Forest range, through the use of camera trappings that were also used to verify if dogs and wild boar overlap in space and activity time. Wild boars seem to dominate the community, just a few years after their presence was first recorded in the region. Surprisingly, several native endangered mammal species persist in the highly modified landscape of the studied areas, but their population trends are still unknown. Wild boars and dogs generally occupy the same areas; however, they do not overlap in activity time, which is an indicative that it is unlikely that the dogs can effectively protect the crops.

Background: Tetracentron sinense Oliv., is an endangered, broad-leaved tree distributed in south-central China. Structural characteristics of the community and dominant tree population niches in T. sinense communities are currently unclear. Questions: (1) What is the status of T. sinense populations in the community? (2) What are the interspecies interactions between T. sinense populations and its associated species. Study sites and dates: T. sinense communities in Meigu Dafengding Nature Reserve in southwest China in 2014. Methods: Six sites of 400 m2 were studied for importance value, special diversity, niche breadth, and overlap of dominant tree populations. Results: There were 80 species, 67 genera, and 41 families of vascular plants. Sixty-one genera of seed plants in T. sinense communities were classified into 9 types. The North Temperate genus was the largest, accounting for 44.26 %. Species richness, species diversity, and evenness indexes were all low. There were 6 dominant tree populations in T. sinense communities, and the importance values and niche breadths of T. sinense populations were significantly higher than other species. Horizontal niche overlaps between T. sinense and Pterocarya stenoptera, Acer pictum subsp. mono, and Cercidiphyllum japonicum were high; the vertical niche overlaps between T. sinense and these species were all greater than 0.7. Conclusions: T. sinense communities have North Temperate character, and are immature and unstable communities, still in the early stage of succession. T. sinense is the edificator tree in the communities. A high similarity of habitat demand and strong interspecific competition for light exist between T. sinense and its associated trees.

Foram examinados 1.069 indivíduos de 13 espécies de membracídeos coletados em suas plantas hospedeiras, entre agosto de 2004 e setembro de 2005, em uma região do semi-árido da Paraíba, Nordeste do Brasil. Enchenopa concolor (Fairmaire, 1846) (31,6%) e E. euniceae Creão-Duarte & Rothéa, 2006 (24,8%) foram as espécies mais abundantes. Cinco famílias de plantas hospedeiras abrigaram esses insetos. Entre essas famílias, Fabaceae apresentou maior riqueza (12) e abundância (70,3%) de membracídeos. Darnis olivacea Fabricius, 1803, Hygris beckeri Sakakibara, 1998 e Sundarion flavum (Fairmaire, 1846) apresentaram os maiores valores de amplitude de nicho. Entre as espécies mais abundantes, E. minuta Creão-Duarte & Rothéa, 2006 e Micrutalis binaria (Faimaire, 1846) mostraram a maior sobreposição de nicho trófico, mas a sobreposição temporal entre elas foi relativamente baixa. Os resultados revelaram possíveis estratégias desenvolvidas pelas espécies para coexistência e exploração de recursos na Caatinga.We examined 1,069 individuals of 13 species of membracids collected on their host plants, between August 2004 and September 2005, in a semi-arid region, State of Paraíba, Northeastern Brazil. Enchenopa concolor (Fairmaire, 1846) (31.6%) and E. euniceae Creão-Duarte & Rothéa, 2006 (24.8%) were the most abundant species. Five families of host plants harbored these insects. Amongst these families, Fabaceae showed the highest richness (12) and abundance (70.3%) of membracids. Darnis olivacea Fabricius, 1803, Hygris beckeri Sakakibara, 1998 and Sundarion flavum (Fairmaire, 1846) showed the highest values of niche breadth. Amongst the most abundant species, E. minuta Creão-Duarte & Rothéa, 2006 and Micrutalis binaria (Faimaire, 1846) showed the highest trophic niche overlap, but the temporal overlap between them was relatively low. The results revealed possible strategies developed by the species for coexistence and utilization of resources in Caatinga.

The pampas deer (Ozotoceros bezoarticus Linnaeus, 1758) was in the recent past one of the most characteristic species in the Uruguayan grasslands. However, today the species is very rare, with small relict populations inhabiting in few ranches. To improve our understanding of pampas deer habitat use in modified ecosystems and propose management guidelines we analyzed the pampas deer feeding ecology at Los Ajos ranch. We performed an annual vegetation survey with the purpose to identify the main components of pampas's deer diet and the spatial overlap with livestock. Vegetation offer was characterized by predominance of monocotyledon plants; in three of the four sample periods. The preference values for the crops were positive for ryegrass in winter (0.24) and spring (0.54), the moments of greatest productivity of this pasture; while the rice crops values were negative all year round. The spatial overlap indexes with sheep show a complete exclusion, whereas with cattle the indexes gave values of 0.95 in spring to 0.14 in summer. The niche amplitude was significantly correlated with the spatial overlap levels with cattle. Pampas deer foraging behaviour is opportunistic, typical of mixed feeders. Conservation efforts should focus on implementation of management guidelines of agriculture and cattle breeding activities.El venado de campo (Ozotoceros bezoarticus Linnaeus, 1758) fue en el pasado reciente una especie focal de las pasturas uruguayas. Sin embargo, hoy día es una especie rara, con pequeñas poblaciones aisladas que ocupan establecimientos agropecuarios. En este trabajo se analizan aspectos de la ecología trófica en una población de venado de campo. El objetivo es: comprender la interacción entre esta especie y un ecosistema modificado por la actividad agrícola-ganadera. Se busca así proponer medidas de manejo de la población y del ambiente que ocupa. En este trabajo se identifican los principales componentes de la dieta y el grado de solapamiento espacial con el ganado doméstico, para ello se realizó un muestreo anual de la vegetación, se colectaron fecas de venado de campo y se analizó la distribución espacial de los distintos herbívoros que ocupan el establecimiento agropecuario. La oferta de vegetación se caracterizó, en tres de cuatro períodos de muestreo, por una predominancia de plantas monocotiledóneas. Los valores de preferencia para los cultivos fueron positivos para el ryegrass en invierno (0.24) y primavera (0.54), los momentos de mayor productividad de esta pastura; mientras que el cultivo de arroz mostró valores negativos de preferencia a lo largo de todo el año de estudio. Los índices de solapamiento espacial mostraron una completa exclusión con el ganado ovino, mientras que con el ganado bovino se obtuvieron índices de 0.95 en primavera a 0.14 en el verano. La amplitud de nicho tuvo una correlación significativa con el nivel de solapamiento espacial con el ganado vacuno. El comportamiento de forrajeo del venado de campo es oportunista, típico de los rumiantes de tipo intermedio (mixed feeders). Los esfuerzos de conservación deben focalizarse en la implementación de lineamientos de manejo de las actividades agrícolas-ganaderas.

Ecological parameters such as trophic niche overlap and niche breadth were computed from the frequency of all drosophilid species collected in 2001 and 2002, in the urban area of Porto Alegre city, Brazil. Independently of place, drosophilids community composition and components breeding or feeding sites, the highest frequencies of Zaprionus indianus (Gupta, 1970) were obtained during seasons with higher average temperatures, especially during summer. From a total of the 19,146 individuals of Z. indianus sampled, 80% were found in this season. The data of trophic niche breadth suggest a higher opportunism of adult flies in feeding substrate use, but the females are still selective in oviposition substrate choice. For the values of niche overlap, only for some species, did we find any correlation between these and species richness and/or number of resources, and the most of the correlation values considering breeding and feeding sites were positive. The colonization of Z. indianus in Porto Alegre could be leading to adjustments in the survival strategies of the resident species, but it is possible that many species have conditions for coexisting with the invader.Parâmetros ecológicos tais como sobreposição e amplitude de nicho trófico foram aplicados a partir da freqüência de todas as espécies de drosofilídeos coletados em 2001 e 2002 na área urbana da cidade de Porto Alegre, Brasil. Independentemente do local, da composição da comunidade de drosofilídeos e dos componentes sítios de ovoposição e alimentação, as maiores freqüências de Zaprionus indianus (Gupta, 1970) foram obtidas durante as estações com médias de temperatura maiores, especialmente durante o verão. De um total de 19.146 indivíduos de Z. indianus amostrados, 80 % foram coletados nesta estação. Os dados de amplitude de nicho trófico sugerem um maior oportunismo de moscas adultas no uso de substratos para alimentação, mas as fêmeas permanecem seletivas na escolha dos substratos para ovoposição. Para os valores de sobreposição de nicho, somente para algumas espécies, encontramos correlação entre estes e a riqueza de espécies e/ou número de recursos, e a maioria dos valores de correlação considerando sítios de ovoposição e alimentação foram positivos. A colonização de Z. indianus em Porto Alegre pode estar levando a ajustes nas estratégias de sobrevivência de espécies residentes, mas é possível que muitas espécies tenham condições de coexistir com a invasora.

Los sistemas fluviales de la zona central de Chile presentan variaciones estacionales en: caudal, temperatura y conductividad. Esto ha influenciado a la fauna íctica nativa la que ha sido caracterizada como primitiva, representada por un bajo número de géneros y especies. La coexistencia de especies nativas e introducidas en el río Maule, Chile (35°43°S;71°05°W), se remonta a comienzos del siglo XX, sistema en el cual las interacciones ecológicas entre estas especies no han sido suficientemente evaluadas. Para ello, se seleccionaron cuatro estaciones de trabajo en el sector andino del río Maule y sus tributarios, en dos periodos del año 1988. La fauna íctica se obtuvo realizando censo total, con un equipo de pesca eléctrica, analizándose el contenido estomacal de 142 ejemplares de Oncorhynchus mykiss, Basilichthys australis y Salmo trutta. La dieta de la mayoría de los peces analizados estuvo compuesta de organismos bentónicos, donde los taxa predominantes fueron Chironomidae, Ephemeroptera y Trichoptera. Se utilizó el índice de Horn para comparar la sobreposición de nicho trófico entre las diferentes especies, encontrándose un alto grado de sobreposición de nicho trófico en todas las estaciones y localidades. La sobreposición de nicho trófico y la diversidad bentónica se asociaron negativamente, lo que podría indicar cambios en la intensidad de las interacciones ecológicas causadas por cambios en el gradiente de recursos.Fluvial systems of central Chile show seasonal variations in: caudal, temperature and conductivity. This has influenced the ichthic native fauna, which has been characterized as primitive, with a low number of genera and species. The coexistence on native and exotic fishes in the Maule river, Chile (35°43°S;71°05°W), is registered since the beginning of the XX century; system in which the ecological interactions between these species have not been adequately evaluated. For this, in between two different seasons of the year 1988, four different locations were selected in the Andean zone of the Maule river and its tributaries. The ichthic fauna was obtained using total census, with electrofishing equipment, stomach contents of 142 specimens of Oncorhynchus mykiss, Basilichthys australis and Salmo trutta were analized. The principal diet of the fishes analysed was basically benthic organisms, where Chironomidae, Ephemoroptera and Trichoptera were the predominant. Horn°s index was used to compare trophic niche overlap among species, finding a high overlap index in all seasons and locations. Niche overlap and benthic diversity showed a negative relationship, this may indicate changes in the intensity of ecological interactions caused by changes in the gradient of resources

ABSTRACT The coexistence of species with similar ecological requirements (food, space, time) has typically drawn attention of researchers because competition for resources is expected to be high. The diet and microhabitat occupation of two morphologically and ecologically similar species of Hylidae (Anura), Dendropsophus microcephalus and Scarthyla vigilans, were analyzed at a locality in north-western Venezuela, with the aim of addressing the potential for space and food competition between them. Diet was estimated through the analysis of stomach contents and microhabitat occupation was estimated through recordings of perch type, height and horizontal distance to water. Thirty-six prey categories (32 families, 4 orders) of arthropods were identified: 30 categories in D. microcephalus and 21 categories in S. vigilans. The most important prey (RII) in D. microcephalus were Agelenidae (11.1%), Tachinidae (9.32%) and Lepidoptera-larvae (7.96%). Gryllidae (14.13%), Cicadidae (9.1%), Cicadellidae (8.3%) and Delphacidae (8.02%) were the most important in S. vigilans. Diet overlap was relatively low (0.32). Both species have relatively generalist diets. Both species occupied the same type of perches (leaves and stems of Dicotyledons and Monocotyledons) and heights (average: S. vigilans, 24 ± 16.2 cm; D. microcephalus, 22.7 ± 9.5 cm). The potential for space competition is high if perches are limited and food competition is expected to be low.