scholarly journals Shifting cultivation and hunting across the savanna-forest mosaic in the Gran Sabana, Venezuela: facing changes

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11612
Author(s):  
Izabela Stachowicz ◽  
José R. Ferrer-Paris ◽  
Ada Sanchez-Mercado

Background Human encroachment and overexploitation of natural resources in the Neotropics is constantly increasing. Indigenous communities all across the Amazon, are trapped between a population rise and a hot debate about the sustainability of hunting rates. The Garden Hunting hypothesis states that shifting cultivation schemes (conucos) used by Amazon indigenous communities may generate favorable conditions, increasing abundance of small and medium wildlife species close to the ‘gardens’ providing game for indigenous hunters. Methods Here, we combined camera trap surveys and spatially explicit interview dataset on Pemón indigenous hunting scope and occurrence in a mosaic of savanna and forest in the Gran Sabana, Venezuela to evaluate to what extent the wildlife resource use corresponds to Garden Hunting hypothesis. We applied the Royle–Nichols model and binomial regression in order to: (1) assess whether abundance of small and medium wildlife species is higher close to conucos and (2) evaluate whether hunters select hunting localities based on accessibility to wildlife resources (closeness to conuco) more than wildlife abundance. Results We find mixed evidence supporting the Garden Hunting hypothesis predictions. Abundance of small and medium species was high close to conucos but the pattern was not statistically significant for most of them. Pemón seem to hunt in locations dominated by forest, where species abundance was predicted to be higher, than in close vicinity to conucos. Hunting scope was focused on the most abundant species located close to the conuco (Cuniculus paca), but also in less abundant and unavailable species (Crax alector, Tapirus terrestris and Odocoileus virginianus). Conclusions Our research provided the first attempt of a systematic sampling survey in the Gran Sabana, generating a quantitative dataset that not only describes the current pattern of wildlife abundance, but sets the base-line to monitor temporal and spatial change in this region of highland Amazon. We discuss the applicability of the estimates generated as a baseline as well as, environmental challenges imposed by economic, social and cultural changes such as mining encroachment for wildlife management.

Author(s):  
M. I. Dzhalalova ◽  
A. B. Biarslanov ◽  
D. B. Asgerova

The state of plant communities in areas located in the Tersko-Sulak lowland was studied by assessing phytocenotic indicators: the structure of vegetation cover, projective cover, species diversity, species abundance and elevated production, as well as automated decoding methods. There are almost no virgin soils and natural phytocenoses here; all of them have been transformed into agrocenoses (irrigated arable lands and hayfields, rice-trees and pastures). The long-term impact on pasture ecosystems of natural and anthropogenic factors leads to significant changes in the indigenous communities of this region. Phytocenoses are formed mainly by dry-steppe types of cereals with the participation of feather grass, forbs and ephemera, a semi-desert haloxerophytic shrub - Taurida wormwood. At the base of the grass stand is common coastal wormwood and Taurida wormwood - species resistant to anthropogenic influences. Anthropogenic impacts have led to a decrease in the number of species of feed-rich grain crops and a decrease in the overall productivity of pastures. Plant communities in all areas are littered with ruderal species. The seasonal dynamics of the land cover of the sites was estimated by the methods of automatic decoding of satellite images of the Landsat8 OLI series satellite for 2015, dated by the periods: spring - May 20, summer - July 23, autumn - October 20. Satellite imagery data obtained by Landsat satellite with a resolution in the multispectral image of 30 m per pixel, and in the panchromatic image - 10 m per pixel, which correspond to the requirements for satellite imagery to assess the dynamics of soil and vegetation cover. Lower resolution data, for example, NDVI MODIS, does not provide a reliable reflection of the state of soil and vegetation cover under arid conditions. In this regard, remote sensing data obtained from the Internet resource https://earthexplorer.usgs.gov/ was used.


Author(s):  
HE Dienye ◽  
OA Olopade ◽  
SA Toby

A study on the catch composition and diversity of cast net fisheries was conducted between May and August, 2017 in the New Calabar River, Rivers state, using cast net of varying mesh sizes (1.5mm and 2.5mm). Fish samples were collected from three sampling stations, viz. Station1- Aluu, Station 2- Choba and Station 3- Iwofe. The fish species recorded comprised of 26 species under 11 families, and one decapod crustacean. The three most abundant species were; Coptodon guineensis (25.11%), Coptodon zilli (18.56%) both from the Cichlidae family, and Penaeus nitialis (10.90%) from the Penaeidae family, while the least abundant species was Liza grandisquamis (0.13%) from the Mugilidae family. The diversity indices showed that station 2 recorded the highest number of species (21) while station 1 recorded the lowest with (12) species. Simpson’s indexes of diversity, Simpson’s reciprocal index, Shannon- weiner index, and Pielou’s evenness index, were estimated. This study serves as a base line data which will assist relevant bodies in the management and conservation of fisheries resources in the New Calabar River. It is therefore recommended that for an improved and sustainable exploitation and management of fisheries resources of the New Calabar River, proper monitoring and management for fish stock must be done.J. Biodivers. Conserv. Bioresour. Manag. 2018, 4(1): 19-26


Author(s):  
Tammy Heise

Since the early 19th century, the expansion of American empire has constrained Native American autonomy and cultural expression. Native American history simply cannot be told apart from accounts of violent dispossession of land, languages, and lifeways. The pressures exerted on Native Americans by U.S. colonialism were intense and far-reaching: U.S. officials sought no less than the complete eradication of Native cultures through the assimilation policies they devised in the 19th century and beyond. Their efforts, however, never went uncontested. Despite significant asymmetries in political power and material resources, Native Americans developed a range of strategies to ensure the survival of their communities in the complicated colonial context created by American expansion. Their activism meant that U.S. colonialism operated as a dynamic process that facilitated various forms of cultural innovation. With survival as their goal, Native American responses to U.S. colonialism can be mapped on a continuum of resistance in which accommodation and militancy exist as related impulses. Native Americans selectively deployed various expressions of resistance according to the particular political circumstances they faced. This strategy allowed them to facilitate an array of cultural changes intended to preserve their own cultural integrity by mitigating the most damaging effects of white rule. Because religion provided the language and logic of U.S. colonial expansion and Native American resistance, it functioned as a powerful medium for cross-cultural communication and exchange in the American colonial context. Religion facilitated engagement with white (mostly Protestant) Christian missionaries and allowed Native Americans to embrace some aspects of white American culture while rejecting others (even within the context of Native conversion to Christianity). It also allowed for flexible responses to U.S. consolidation policies intended to constrain Native autonomy still further by extending the reservation system, missionary oversight of indigenous communities, and land use in the late 19th century. Tribes that fought consolidation through the armed rebellions of the 1870s could find reasons to accept reservation life once continued military action became untenable. Once settled on reservations, these same tribes could deploy new strategies of resistance to make reservation life more tolerable. In this environment of religious innovation and resistance, new religious movements like the Ghost Dance and peyote religion arose to challenge the legitimacy of U.S. colonialism more directly through their revolutionary combinations of Native and Christian forms.


2020 ◽  
Vol 6 (29) ◽  
pp. eaaz9037
Author(s):  
Paula Villa Martín ◽  
Aleš Buček ◽  
Thomas Bourguignon ◽  
Simone Pigolotti

Oceans host communities of plankton composed of relatively few abundant species and many rare species. The number of rare protist species in these communities, as estimated in metagenomic studies, decays as a steep power law of their abundance. The ecological factors at the origin of this pattern remain elusive. We propose that chaotic advection by oceanic currents affects biodiversity patterns of rare species. To test this hypothesis, we introduce a spatially explicit coalescence model that reconstructs the species diversity of a sample of water. Our model predicts, in the presence of chaotic advection, a steeper power law decay of the species abundance distribution and a steeper increase of the number of observed species with sample size. A comparison of metagenomic studies of planktonic protist communities in oceans and in lakes quantitatively confirms our prediction. Our results support that oceanic currents positively affect the diversity of rare aquatic microbes.


2008 ◽  
Vol 68 (3) ◽  
pp. 519-528 ◽  
Author(s):  
MLT. Buschini ◽  
NA. Borba ◽  
AD. Brescovit

This study was carried out in the Parque Municipal das Araucárias, in the municipality of Guarapuava, southern Brazil. A total of 449 T. lactitarse nests were collected using trap-nests of different diameters. Fifty three species of spiders belonging to 7 families were captured by T. lactitarse. Araneidae was the most captured family and has been strongly represented by the genus Eustala. Through Bray-Curtis's coefficient and the unweighted pair group method average (UPGMA), the spiders species can be divided into 3 groups: the smaller group includes the most abundant species (Eustala sp1, Eustala sp2, Acacesia villalobosi, Alpaida sp1 and Araneus corporosus), the second group includes species with intermediate abundance (Wagneriana iguape, Araneus omnicolor, Eustala sp4, Alpaida grayi, Eustala sp3, Larinia t-notata, Mangora sp1 and Wagneriana iguape), and the third and largest group includes the least abundant species (Aysha gr. brevimana 1, Eustala sp5, Wagneriana eupalaestra, Alpaida scriba, Alpaida veniliae, Araneus aff. omnicolor, Araneus sicki, Eustala sp8, Mangora sp2, Mangora sp3, Wagneriana juquia, Alpaida sp2, Araneus blumenau, Eustala sp6, Eustala sp7 and Ocrepeira galianoae). Of 2,029 identified spiders, 1,171 were captured in the Araucaria forest, 612 in grassland areas and 246 in the swamp. Grassland and swamp areas evidenced greater similarity between them than to the Araucaria Forest, regarding presence-absence of spider species in T. lactitarse's diet, as well as regarding species abundance in these habitats. The juvenile number (56%) was significantly higher than the female (38%) and male (6%) percentages.


2020 ◽  
Vol 57 (6) ◽  
pp. 1913-1919
Author(s):  
Walter Santos de Araújo ◽  
Thallyta Maria Vieira ◽  
Guilherme Antunes de Souza ◽  
Isaque Clementino Bezerra ◽  
Paulo Henrique Costa Corgosinho ◽  
...  

Abstract Mosquitoes (Diptera: Culicidae) are one of the most important disease vector species in the world. Many species have a high degree of anthropophilia and are often found in human habitations. In the present study, we have inventoried the nocturnal mosquito assemblage in intra-, peri-, and extradomicile environments in four municipalities in Pará, Brazil. At each municipality, a residence was selected and the mosquitoes were sampled using the protected human attraction capture and Shannon trap methods in April (rainy season) and August 2018 (dry season). We have collected a total of 696 mosquito specimens belonging to 8 genera and 17 species. The most abundant species were Mansonia (Mansonoides) titillans (Walker) (366/696, 52.6%), Anopheles (Nyssorhynchus) albitarsis Lynch-Arribálzaga (97/696, 13.9%), and Culex (Culex) quinquefasciatus Say (93/696, 13.4%). Mosquito richness, abundance, and composition did not differ between intra-, peri-, and extradomicile environments suggesting limited habitat segregation among the different species. However, mosquito species richness and mosquito species abundance were significantly higher during the rainy season than during the dry season, suggesting increased mosquito activity during the rainy season. We detected several important vector species of human diseases including Aedes (Stegomyia) aegypti (Linnaeus), Anopheles (Nyssorhynchus) darlingi Root, Haemagogus (Conopostegus) leucocelaenus (Dyar and Shannon), Coquillettidia (Coquillettidia) venezuelensis (Theobald), and Culex (Culex) quinquefasciatus which are the main transmitters of dengue, malaria, yellow fever, mayaro, and oropouche fever, respectively. As inventories of disease-carrying mosquitoes in the region are very scarce, mainly in residential environments, our results suggest high potential for mosquito-borne disease transmission in Pará State.


2020 ◽  
Vol 55 (3) ◽  
pp. 329-343
Author(s):  
Kenneth W. McCravy ◽  
Jason E. Willand

Abstract The Carabidae is a diverse family of beetles with many species of interest in conservation and biological control. Carabid beetle adult seasonal activity patterns were studied in a west-central Illinois forest/reconstructed tallgrass prairie matrix over a 2-yr period using pitfall traps. We found a threefold or greater difference in carabid abundance between years. Despite lower abundance, a second year of sampling yielded seven previously undetected species. Abundance and species richness were greatest in May–July and lower in August–October. Relative abundance and species richness were consistent among months between years. Shannon diversity and effective number of species were lowest in June and July. Cyclotrachelus sodalis (LeConte) and Chlaenius platyderus Chaudoir were the two most abundant species, comprising 54.3% of total captures. These species were most abundant in July and June, respectively. Most species showed greatest abundance in spring or early summer, and declined thereafter. Collections of several species were suggestive of bimodal seasonal patterns. Carabid species composition differed significantly among months, but not between years. Our results document seasonal variation in carabid abundance and species composition, and show that sampling throughout the growing season, and multiple sampling years, provide substantial benefits for assessments of carabid diversity in this region.


2001 ◽  
Vol 36 (2) ◽  
pp. 114-121 ◽  
Author(s):  
John P. Smith ◽  
Thomas G. Floore

Twenty-nine species representing eight genera, numerous new county records and one state record, Mansonia titillans (Walker), were collected in a surveillance project conducted in 20 southern Georgia counties during the summer of 1997. A detailed report of species abundance and diversity is presented. Overall, as sampled by CO2 light traps, Culex quinquefasciatus Say was the most widely distributed species and Aedes vexans (Meigen) was the most abundant species followed closely by Aedes atlanticus Dyer and Knab.


2011 ◽  
Vol 6 (1) ◽  
pp. 118-129 ◽  
Author(s):  
Ivan Gelbič ◽  
Jiří Olejníček

AbstractEcological investigations of long-legged flies (Dolichopodidae) were carried out in wet meadow wetlands near České Budějovice, Czech Republic. Sampling was performed during the adult flies’ seasonal activity (March–October) in 2002, 2003 and 2004 using yellow pan traps, Malaise traps, emergence traps, and by sweeping. Altogether 5,697 specimens of 78 species of Dolichopodidae were collected, identified and analysed. The study examined community structure, species abundance, and diversity (Shannon-Weaver’s index - H’; Sheldon’s equitability index - E). Chrysotus cilipes, C. gramineus and Dolichopus ungulatus were the most abundant species in all three years. Species richness and diversity seem strongly affected by soil moisture.


2019 ◽  
Vol 4 (1) ◽  
pp. 1
Author(s):  
Dian Kartika Santoso ◽  
Antariksa Antariksa ◽  
Sri Utami

<p>ABSTRACT</p><p>People in Ngadas Village have enough time to live in their fields. Therefore, the community build farmhouses to help farming activities. However, as an agricultural landscape, cultivation in Ngadas Village has various dynamics. Changes that occur in the agricultural landscape can be traced through agricultural features formed by the type of agricultural land use. In addition, it can be traced through cultural features that are the result of interactions between human activities and the environment such as farmhouses. Therefore, this study aims to find out the implications of agricultural features on cultural features, especially space in farmhouses. The in-depth interview and observation methods were conducted to identify, then the data obtained were analysed by synchronous and diachronic methods. So, the changes that occur can be determined descriptively. The results of the study show that the culture of shifting cultivation that has become permanent causes the fields to develop along with the changes in the plants that have been planted, the addition of activities and intensity of plant management. More fixed location of the farm more developed and permanent farmhouses has been built. More activities carried out in the fields and the higher intensity of plant management, the wider and more space needed for the fields.</p><p>Keywords: Agrarian culture, Agricultural landscape, Farmhouses</p>


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