High Density Of Individuals Research Articles

Spatial and temporal variability of fouling communities on oyster spat collectors at Inhaca Island Southern Mozambique: Exploring the influence on recruitment of the oysters Pinctada capensis and Saccostrea cucullata

In the transition from pelagic larva to benthic adult, larvae likely encounter a diverse assemblage of resident invertebrates in their habitat, which may also compete for space during post-settlement periods. Fouling fauna in rocky and seagrass habitats on Inhaca Island, southern Mozambique, was evaluated over 4 months in each of two seasons on oyster collectors fixed at 2 cm above the bottom. As expected, two species of oysters recruited to tiles: the rock oyster Saccostrea cucullata in rocky habitats and the pearl oyster, Pinctada capensis in seagrass habitats. The composition and density of other fouling fauna varied among habitats, location, seasons and surfaces and depending on the duration of the deployment. In seagrass habitats, oysters and barnacles were generally less abundant, allowing other taxa to have higher relative abundance, while higher density of individuals was recorded in rocky habitat. Barnacles dominate among fouling fauna on collectors in both habitats. Despite evidence consistent with negative interactions between oysters and barnacles, the effects of other fouling fauna on oyster abundance appear modest up to 4 months after tiles are placed. Overall, the results help improve our general understanding of the environmental processes that affect the colonisation of intertidal invertebrates, particularly in the southwestern Indian Ocean.

First record of Bursatella leachii de Blainville, 1817 (Mollusca: Gastropoda: Aplysiidae) in Corsica (France, NW Mediterranean)

This study reports for the first time the occurrence of ragged sea hare Bursatella leachii de Blainville, 1817 in Corsica (France, NW Mediterranean Sea). The species has colonized the shallow waters (0.1–0.5 m depth) of Diana Lagoon mainly constituted of sandy-muddy bottoms and Cymodocea nodosa and Zostera noltei seagrass beds. A total of 166 individuals were inventoried in June 2023 during the survey carried out along more than 300 m of shoreline. The highest density of individuals (0.63 ind m−2) was mainly reported in very warm and sheltered water basins formed by the accumulation of woody debris (mean ± SE: 0.17 ± 0.06 ind m−2). Morphometric measurements of specimens showed an average body length of 54.3 ± 1.7 mm and weight of 14.7 ± 0.8 g. The introduction pathways of this species into this coastal lagoon may have resulted from the natural dispersal of larvae or juveniles or via the shellfish farming located in the lagoon. Extensive monitoring should be carried out along the coast of Corsica to shed light on the occurrence of the species and its spatio-temporal spread. A literature review on B. leachii has enabled us to update the existing dataset on the species distribution. The species is now confirmed from 21 out of 23 countries surrounding the Mediterranean basin.

Preliminary study of the population and reproductive dynamics of Echinaster sepositus (Spinulosida: Echinasteridae) in Cala del Racó

Introduction: The red starfish (Echinaster sepositus) is one of the most common asteroid species in the Mediterranean Sea. However, information about their biology or their role in benthic communities is scarce.
 Objective: This study aims to provide new information on the ecology of this species through the temporal characterization of the population of E. sepositus in Cala del Racó (Alicante, Spain) and the in situ monitoring of its reproductive cycle.
 Methods: For this purpose, three study areas were established at different depths. For each of the recorded starfish, data about the size, the substrate on which it was found, the area, the depth and the sex in the case of observing the reproduction were collected.
 Results: A total of 19 samplings have been carried out throughout a year of study. In this way, it has been possible to observe that the density of individuals increases in the shallower zone during autumn and winter, when the temperature drops to 14.13 ºC, while it decreases in spring and summer when the temperature rises to 27.17 ºC. Those results are reversed in the deepest part of the study. The highest density of individuals (0.51 ind/m2) occurred in October. Arborescent photophilic algae and crustose coralline algae were the substrates with the highest number of E. sepositus recorded. Medium to large specimens are located preferably on crustose coralline algae or arborescent photophilic algae, while smaller individuals were mostly located on Posidonia oceanica. No specimens of E. sepositus were observed spawning.
 Conclusions: Data leads to assume that there is a migration of starfishes towards more superficial areas when the water is at colder temperature and towards deeper areas when the temperature increases. It is valued the possibility that there is a change in the nutritional needs of E. sepositus throughout its development. According to our observations, the future reproduction studies should be concentrated between late-summer and early-autumn.

Polyandry contributes to Gonipterus platensis (Coleoptera: Curculionidae) rearing.

Gonipterus platensis Marelli, 1926 (Coleoptera: Curculionidae) is one of the main defoliating beetles in Eucalyptus plantations. Biological control with egg parasitoids is one of the main control strategies for this pest and a constant supply of fresh host eggs is required to rear the parasitoids. Polyandry can influence Gonipterus oviposition by increasing female fecundity and fertility; however, the high density of individuals in laboratory colonies can lead to male harassment, resulting in lower reproduction rate. The aim of this study was to measure the effects of monoandry and polyandry on the reproduction of G. platensis and the effects of male harassment on laboratory rearing conditions. Reproductive parameters were compared between three treatments: monoandry, where the female was allowed to mate daily with the same male; no choice polyandry, where the female was allowed to mate daily with a different male; and polyandry with choice, where the female was allowed to mate daily, but with a choice between five different males. Another experiment varying the density of males was conducted to evaluate the effect of male harassment. Polyandry with choice resulted in the longest period of oviposition, highest fecundity and highest number of eggs per egg capsules when compared to monoandrous females. No negative effect related to male harassment in the laboratory, such as decreased fertility, fecundity, or number of eggs per egg capsule, was detected. Polyandry contributes to mass rearing as it increases fecundity and oviposition period on females and there is no evidence of male harassment on G. platensis.

Flight capabilities of invasive yellowjacket Vespula germanica drones: the effect of kinship and nutrition

AbstractDispersal is a multifactorial process which may influence, among several others, population dynamics, inbreeding likelihood, and mate competition. For species that disperse by flight, many studies have suggested that life‐history traits, such as body size or nutritional condition, could promote variation in flight capabilities and, consequently, on dispersal behavior. Eusocial hymenopterans are likely to experience high densities of related reproductive individuals near their nests, thus increasing probabilities of inbred matings and kin competition. Spatial segregation resulting from differences in flight capabilities of Vespula germanica (Fabricius) (Hymenoptera: Vespidae) nestmate drones could reduce interactions with kin, thus decrease inbreeding and kin competition. Our aim was to characterize, in the laboratory, flight capabilities of sibling drones and elucidate traits that could affect it, focusing on the relevance of carbohydrate intake (diets with different sugar concentration) during early adulthood. Our results indicate that in tethered flight mill assays, V. germanica drones have highly variable flight capabilities within and between nests, with most drones likely to remain relatively close to their nest of origin. The observed flight capabilities are affected by nutrition, with those individuals better nurtured (i.e., with higher nutritional index), flying farther distances. Additionally, diets with variable carbohydrate concentration provided during early adulthood did not affect flight capabilities (only those exposed to a carbohydrate‐free diet had reduced flight distances and speeds), suggesting that nutrition during larval stages is determinant for flight. Our findings contribute to the understanding of the mechanisms underlying V. germanica drone dispersal behavior which, in turn, might influence inbreeding likelihood in the species.

Krmiva s povećanim sadržajem antocijanina u hranidbi životinja

The word anthocyanin comes from the Greek words Anthos, meaning flower, and kyanose, meaning blue. Anthocyanins give red, purple, and blue colors to plants. In acidic conditions, they appear as red pigments and in alkaline conditions, they appear as blue pigments. The intensive nature of agricultural (animal) production, with a high density of individuals in animal production facilities, very often contributes to the occurrence of disorders and diseases in animals that threaten this production. A major problem for the animal organism is the effects and consequences of oxidative stress or excessive production of free radicals, which are the main cause of metabolic disorders in cows in the transition period, and antioxidants can prevent or at least mitigate these conditions. Anthocyanins as a source of natural antioxidants play an important role in increasing the antioxidant potential that protects the cell against oxidative damage. Some anthocyanin species may have an enhancing effect on mRNA expression and superoxide dismutase activity. The bioavailability of anthocyanins is relatively low due to poor absorption in the digestive tract. In our region, colored corn, wheat, barley, and sorghum can be used as anthocyanin sources in the domestic animal diet, black soybean, rye, and black and red rice also have high anthocyanin content. Purple corn can accumulate much more anthocyanins than commercial corn varieties.

Diameter Distribution of Vouacapoua americana Aublet in the Brazilian Amazon

Vouacapoua americana Aublet was classified as endangered in 2013 and its extraction banned in 2014. Forest management allows conservation and sustainable production, but, for this, knowledge of diameter distribution is fundamental. This study aimed to characterize and analyze diameter distribution patterns of the species at different sites in the Brazilian Amazon. Data on trees with diameter ≥ 10 cm were acquired from continuous forest in permanent sample plots and preharvest forest inventories (PHFIs) of nine forest management areas. Absolute density, diameter distribution, and De Liocourt quotient (q) were calculated. Diameter distributions were fitted by a linearized Meyer type I distribution function, and the similarity between distributions was analyzed by the nonparametric Kruskal-Wallis test (H-test). The species showed high density (6.31 to 25.55 trees/ha). Mensrured diameters ranged from 10.00 to 127.32 cm. A decreasing behavior was observed in all diameter distributions, with few discontinuous distributions and mostly truncated distributions. The De Liocourt quotient (q) did not show constancy or proximity, with values ranging from 0.4 to 23.48. Diameter distributions did not differ by the Kruskal-Wallis test (H = 15.45, p = 0.3479). Diameter distributions fitted by the Meyer model resulted in an inverted “J”-like curve. The diameter structure showed a high density of individuals, a decreasing distribution from smaller to larger diameter classes, a characteristic inverted “J” pattern, and unbalanced diameter distributions.

EFEITO DA REMOÇÃO DE INDIVÍDUOS REGENERANTES NA DINÂMICA DO BANCO DE Plântulas EM COMUNIDADES DE VEGETAIS

ABSTRACT The use of forest seedling banks is recommended for producing seedlings of species essential for specific forest typologies for which propagation poses challenges. However, given the lack of understanding of how human intervention, such as the removal of regenerating individuals from the forest, influences the composition and structure of the plant community, there is a pressing need for further research. Our primary objective here was to identify the effects of seedling removal on natural regeneration in forest communities and to characterize seedling bank dynamics three years after anthropogenic intervention. A randomized block design was used for the experiment, consisting of five removal intensities (0, 25, 50, 75, and 100% removal), with evaluations conducted every three months for three years. All individuals of the shrub-arboreal component between 5-55 cm heights were measured. Collected data were analyzed to determine the impacts of the removal of individuals and the influence of environmental elements on the seedling community. We found that the shrub-arboreal component of the forest community exhibited marked resilience three years following the removal of regenerating individuals. Removal of up to 50% of regenerating individuals does not appear to interfere with plant community dynamics, suggesting species with a high density of individuals in the seedling bank are resilient to the impacts of human intervention. Although climatic seasonality also affects seedling bank dynamics in plant communities, this effect depends on the level of human intervention in an area and, therefore, has been omitted from the analysis.

AUTOECOLOGIA, DIVERSIDADE E ESTRUTURA GENÉTICA INTERNA DE Ocotea porosa (NEES & MART.) BARROSO: SUBSÍDIOS PARA A COLETA DE SEMENTES

ABSTRACT Ecological restoration mitigates the negative effects of fragmentation and habitat loss. This practice allows the conservation of key species, such as Ocotea porosa, a tree native to the Araucaria Forest and extremely endangered. A key point in restoration projects is the source of seeds, as well as guidelines for collection. When carried out under technical criteria, the collection allows the maintenance of genetic diversity and adaptive potential in restoration plantations. Given the importance of seed source, genetic diversity, and adaptive potential, this study aimed to define areas and criteria for collecting seeds by characterizing the demography, genetics, and reproductive phenology of an O. porosa population. A plot of 16 hectares was installed in the municipality of Passos Maia, Santa Catarina, Brazil, and a demographic survey of trees with diameter at breast height (DBH) > 15 cm was carried out. Indices of diversity and internal genetic structure (IGS) were estimated using allozyme markers. The reproductive phenology of 67 individuals was evaluated during 8 months. The studied population showed a high density of individuals (10.7 ind. ha-1) with normal diametric distribution. The phenological pattern of the species is regular, seasonal, and annual. The evaluated population showed high genetic diversity, high fixation index, and significant IGS up to 80 meters away. Based on these results, the evaluated fragment can be used as a seed collection area. It has high genetic diversity, density, and area size sufficient to contain several demes. In addition, it is highly recommended that the matrices be at least 80 meters apart to avoid the effects of significant IGS.

Variations in home range and core area of red-backed voles (Myodes regulus) in response to various ecological factors

The characteristics of animal distribution are determined by interactions between the resource requirements of animals and ecological factors. This study sought to evaluate the effects of diverse ecological factors on the home range and core area of red-backed voles (Myodes regulus) in a natural deciduous forest located on Mt. Gariwang, Pyeongchang and Jeongseon, South Korea. Our study focused on four types of ecological factors: topography, climate, cover, and demography. A total of 29 voles were radio-tracked from August to September 2021. Home range (95% utilization distribution; UD) and core area (50% UD) were calculated using the kernel density estimator (KDE). The home range (1659.49 m2) and core area (317.08 m2) were negatively affected by altitude. The lunar phase and temperature negatively and positively influenced the home range and core area, respectively. The home range was positively affected by understory vegetation, whereas the core area was not. The core area increased within microhabitats with a high density of conspecific individuals, with males having a larger home range (2006.19 m2) and core area (375.40 m2) than females (1043.13 m2 and 213.39 m2, respectively). These findings provide a deeper understanding of the diverse ecological factors affecting the distributions of animals, especially small rodents.

Rainfall effects on Anomalocardia flexuosa densities on the northeastern Brazilian coast using distributed lag models

In this study, the effects of precipitation on Anomalocardia flexuosa densities were analyzed from the perspective of temporal delays between the variables. The collections occurred bi-monthly between April 2016 and February 2018 at Mangue Seco beach, Pernambuco, Brazil. Total densities and densities according to the category of size (small, medium and large), and precipitation were analyzed with autocorrelation and cross-correlation functions, with a retrospective analysis of up to 12 months. Distributed lag models were used among the variables. The maximum density was found in June 2017 (378 ind.m2) for the medium-size category of individuals. Significant autocorrelations occurred for densities (total and average size) and precipitation. In cross-correlation functions, high precipitation for a given month was followed by high densities of total and average individuals for up to two months. Distributed lag models also showed significant values between densities (total and medium-sized) and precipitation, which explained more than 50% of the variability of these two groups. The effect of precipitation was responsible for the increase in the density of A. flexuosa for up to two months, mainly by increasing individuals with medium shell lengths.

Structure, floristic composition and environmental relationships of natural regeneration in a semideciduous seasonal forest

This paper aims to evaluate the floristic and structure of natural regeneration in a forest fragment located in the south of Espírito Santo State, as well as to verify the interaction between vegetation and environmental variables. The study was developed in Private Reserve of Nature Patrimony (RPPN) Cafundó, with twelve sample units (1 x 20m), where three classes based on size - Class 1 (plants between 0.1 and 1m high), Class 2 (plants between 1.1 and 3m high) and Class 3 (plants higher than 3m and less than 5cm DBH). This RPPN has a total area of 517ha, which approximately 358ha were used for allocation of experimental units. Individuals were classified according to ecological group and dispersion syndrome. Floristic diversity, equability, density and frequency of species were also calculated. Analysis of natural regeneration, floristic similarity between natural regeneration and the upper layer as well the regenerating layer interaction with environmental variables was performed through Canonical Correspondence Analysis. We found 678 individuals distributed in 73 morphospecies/species, with Actinostemon klotzschii and Goniorrhachis marginata being the most abundant. Sorensen's similarity between natural regeneration and the adult tree layer was 29%. The most dominant ecological groups were late secondary, while zoochory was the predominant dispersion syndrome among existing species. Shannon diversity index was 3.13 and equability 0.72. Goniorrhachis marginata, Actinostemon klotzschii and Psychotria carthagenensis species had correlation with carbon (C), phosphorus (P), declivity and canopy cover. We concluded that the natural regeneration component within studied area has a high richness and density of individuals when compared to studies developed in similar phytophysiognomies. The studied environmental variables seem to have little influence on the distribution of natural regeneration species in the RPPN, once only carbon, phosphorus, declivity and canopy cover have explained the species distribution within fragment.

Fibropapillomatosis Prevalence and Distribution in Immature Green Turtles (Chelonia mydas) in Martinique Island (Lesser Antilles).

Fibropapillomatosis (FP) threatens the survival of green turtle (Chelonia mydas) populations at a global scale, and human activities are regularly pointed as causes of high FP prevalence. However, the association of ecological factors with the disease's severity in complex coastal systems has not been well established and requires further studies. Based on a set of 405 individuals caught over ten years, this preliminary study provides the first insight of FP in Martinique Island, which is a critical development area for immature green turtles. Our main results are: (i) 12.8% of the individuals were affected by FP, (ii) FP has different prevalence and temporal evolution between very close sites, (iii) green turtles are more frequently affected on the upper body part such as eyes (41.4%), fore flippers (21.9%), and the neck (9.4%), and (iv) high densities of individuals are observed on restricted areas. We hypothesise that turtle's aggregation enhances horizontal transmission of the disease. FP could represent a risk for immature green turtles' survival in the French West Indies, a critical development area, which replenishes the entire Atlantic population. Continuing scientific monitoring is required to identify which factors are implicated in this panzootic disease and ensure the conservation of the green turtle at an international scale.

Soil macrofauna in areas with different successional vegetation stages after Eucalyptus grandis harvest in Brazil

The objective of this study was to evaluate the composition of soil macrofauna over different periods after the harvest of Eucalyptus grandis to understand the ecological restoration process. Data collection was carried out in each climatic season by the “Tropical Soil Biology and Fertility” Program. In general, 25,789 individuals were collected from the soil macrofauna and distributed in 26 taxonomic groups, with the Formicidae family being the most abundant. Of the individuals found, 7,418 were collected during autumn, 7,320 in summer, 5,553 in winter, and 5,498 in spring. The soil macrofauna was influenced by seasonality, with a higher density of individuals in autumn and summer. Regarding functional groups, social groups were dominant in all areas and seasons, comprising 74.50% of the total number of individuals. The detritivores group comprised 17.98% of the total individuals. Herbivores, snails, and slugs accounted for 3.98% of the total individuals. The functional groups detritivores, herbivores, and predators were more abundant in the litter, while the social groups were predominant in the soil depths of 0 to 30 cm. As the forest progressed, the richness of the macrofauna groups increased, demonstrating the influence of successional dynamics on the composition of the soil macrofauna.

Collective close calling mediates group cohesion in foraging meerkats via spatially determined differences in call rates

During group movements, many socially living and group-foraging animals produce contact calls. Contact calls typically function to coordinate and maintain cohesion among group members by providing receivers with information on the callers' location or movement-related motivation. Previous work suggests that meerkats, Suricata suricatta, also produce short-range contact calls, so-called ‘close calls’, while foraging to maintain group cohesion. Yet, the underlying mechanism of how meerkats coordinate cohesion via close calling is unclear. Using a combination of field observations and playback experiments we here show that foraging meerkats adjusted the call rates of their continuously produced close calls depending on their spatial position to group members. Specifically, meerkats called at higher rates when foraging at a closer distance to and when surrounded by conspecifics; however, the number of calling individuals or their call rates did not affect a subject's close call rate. Overall, close call playbacks elicited a call response in receivers and attracted them to the sound source. Our results suggest that differences in individual close call rates are determined by a meerkat's proximity to other group members, being assessed through their vocal interactions. We discuss how local differences in individual call rates may extrapolate to the group level, where emerging ‘vocal hotspots’ indicate areas of high individual density, in turn attracting and potentially guiding group members' movements. Hence, the described pattern illustrates a so far undocumented call mechanism where local differences in the call rates of continuously produced close calls can generate a group level pattern that mediates the cohesion of progressively moving animal groups.

Population size and habitat preference of the Omo River guereza (Colobus guereza guereza) in a multi-habitat matrix in the central highlands of Ethiopia.

Given the current rate of habitat degradation and loss in the tropics, data on primate population densities and habitat use are indispensable for assessing conservation status and designing feasible management plans for primates. The Omo River guereza (Colobus guereza guereza) is a subspecies of the eastern black-and-white colobus monkey endemic to the western Rift Valley forests of Ethiopia. Their restricted distribution along with habitat loss and hunting within their range render them vulnerable to local extirpation and extinction. Furthermore, there are no published data available on the population status and habitat use patterns of the Omo River guereza. We therefore aimed to assess the population size of Omo River guerezas in different habitats (Erica-Juniperus mixed forest, mixed plantation forest, undisturbed natural forest, disturbed natural forest) using transect surveys at Wof-Washa Natural State Forest (WWNSF) in central Ethiopia. Our surveys covered a cumulative distance of 88.5km in four different habitats, during which we recorded a total of 140 Omo River guereza groups. The average group density was 14.3 groups/km2, average individual density was 94.4 individuals/km2, and we estimated the total population size within WWNSF to be 2549 individuals. The sex ratio of the population was split evenly between males and females, though the age classes skewed strongly towards adults. Of the habitats surveyed, the highest group encounter rate (1.83 groups/km) occurred in the disturbed natural forest. However, the highest individual density (110.1 individuals/km2) was recorded in undisturbed natural forest. Still, sizable densities (group and individual) were recorded in three of the disturbed habitats (disturbed natural forest, mixed plantation forest, and to a lesser extent Erica-Juniperus mixed forest). Our study offers the first baseline information with which to compare future population density estimates and habitat use in the range of Omo River guerezas.

Foliar Fungal Endophytes in a Tree Diversity Experiment Are Driven by the Identity but Not the Diversity of Tree Species.

Symbiotic foliar fungal endophytes can have beneficial effects on host trees and might alleviate climate-induced stressors. Whether and how the community of foliar endophytes is dependent on the tree neighborhood is still under debate with contradicting results from different tree diversity experiments. Here, we present our finding regarding the effect of the tree neighborhood from the temperate, densely planted and 12-years-old Kreinitz tree diversity experiment. We used linear models, redundancy analysis, Procrustes analysis and Holm-corrected multiple t-tests to quantify the effects of the plot-level tree neighborhood on the diversity and composition of foliar fungal endophytes in Fagus sylvatica, Quercus petraea and Picea abies. Against our expectations, we did not find an effect of tree diversity on endophyte diversity. Endophyte composition, however, was driven by the identity of the host species. Thirteen endophytes where overabundant in tree species mixtures, which might indicate frequent spillover or positive interactions between foliar endophytes. The independence of the diversity of endophytes from the diversity of tree species might be attributed to the small plot size and the high density of tree individuals. However, the mechanistic causes for these cryptic relationships still remain to be uncovered.

Social Network Analysis Reveals the Subtle Impacts of Tourist Provisioning on the Social Behavior of a Generalist Marine Apex Predator

Shark dive ecotourism is a lucrative industry in many regions around the globe. In some cases, sharks are provisioned using bait, prompting increased research on how baited dives influence shark behavior and yielding mixed results. Effects on patterns of habitat use and movement seemly vary across species and locations. It is unknown, however, whether wide-ranging, marine apex predators respond to provisioning by changing their patterns of grouping or social behavior. We applied a tiered analytical approach (aggregation-gregariousness-social preferences) examining the impact of provisioning on the putative social behavior of tiger sharks (Galeocerdo cuvier) at a dive tourism location in The Bahamas. Using network inference on three years of acoustic tracking data from 48 sharks, we tested for non-random social structure between non-provisioned and provisioned monitoring sites resulting in 12 distinct networks. Generally considered a solitary nomadic predator, we found evidence of sociality in tiger sharks, which varied spatiotemporally. We documented periods of both random (n = 7 networks) and non-random aggregation (n = 5 networks). Three of five non-random aggregations were at locations unimpacted by provisioning regardless of season, one occurred at an active provisioning site during the dry season and one at the same receivers during the wet season when provision activity is less prevalent. Aggregations lasted longer and occurred more frequently at provisioning sites, where gregariousness was also more variable. While differences in gregariousness among individuals was generally predictive of non-random network structure, individual site preferences, size and sex were not. Within five social preference networks, constructed using generalized affiliation indices, network density was lower at provisioning sites, indicating lower connectivity at these locations. We found no evidence of size assortment on preferences. Our data suggest that sociality may occur naturally within the Tiger Beach area, perhaps due to the unusually high density of individuals there. This study demonstrates the existence of periodic social behavior, but also considerable variation in association between tiger sharks, which we argue may help to mitigate any long-term impacts of provisioning on this population. Finally, we illustrate the utility of combining telemetry and social network approaches for assessing the impact of human disturbance on wildlife behavior.

Edge influence on the microclimate and vegetation of fragments of a north Amazonian forest

There are multiple pressures on Amazon forests due to, anthropic activities such as extensive cattle ranching, logging, and legal and illegal crops. These pressures generate highly fragmented landscapes that leads to an increase in forest edges. Thus, forest vegetation exposed to the surrounding open environment generates a series of direct effects that extend into the interior of the forest. Changes in the microclimate are among the most notable effects, and these can impact the composition and structure of the vegetation and affect the alteration of multiple ecological processes and ecosystem services. To better understand these consequences, we evaluated the distance of the edge influence on the microclimate, the composition of the vegetation, and the forest structure in the northern Amazon. We considered two types of edges according to adjacent cover: grasslands dedicated to extensive cattle ranching and rubber plantations (Hevea brasiliensis (Willd. ex A.Juss.) Müll.Arg.). We recorded significant differences in the composition and abundance of plants of all size categories. We found less richness and dominance of generalist species, that are characteristic of disturbed environments, in the forest sector adjacent to pastures. These edges had also lower humidity and higher temperatures than rubber plantations ones. The distance from the edge to the interior also affected the structure of the vegetation, with a higher density of individuals in the interior of the forest and significant differences in the diameter and height of individuals. We argue that the rubber plantations could be used as a forest management strategy of drought adaptation since it forms a less abrupt border and has a buffer function, keeping higher humidity values and lower temperatures than forest edges adjacent to pastures.

Mass occurrence of small isopodan crustaceans in 100-million-year-old amber: an extraordinary view on behaviour of extinct organisms

Within Isopoda (woodlice and relatives), there are lineages characterised by a parasitic lifestyle that all belong to Cymothoida and likely form a monophyletic group. Representatives of Epicaridea (ingroup of Cymothoida) are parasitic on crustaceans and usually go through three distinct larval stages. The fossil record of Epicaridea is sparse and thus little is known about the palaeoecology and the origin of the complex life cycle of modern epicarideans. We present an assemblage of over 100 epicarideans preserved in a single piece of Late Cretaceous Myanmar amber. All individuals are morphologically similar to cryptoniscium stage larvae. The cryptoniscium stage usually constitutes the third and last larval stage. In modern representatives of Epicaridea, the cryptoniscium larvae are planktic and search for suitable host animals or adult females. These fossil specimens, though similar to some extant species, differ from other fossil epicaridean larvae in many aspects. Thus, a new species (and a new genus), Cryptolacruma nidis, is erected. Several factors can favour the preservation of multiple conspecific animals in a single piece of amber. However, the enormous density of epicarideans in the herein presented amber piece can only be explained by circumstances that result in high local densities of individuals, close to the resin-producing tree.