The Huarango in the Desert Riparian and Agricultural Ecosystem

Author(s):  
David Beresford-Jones

This chapter considers the subtler role of Prosopis in underpinning a fragile desert ecology. It is perhaps difficult to exaggerate the dominance of this genus within its desert environments, especially on the coast of Peru, where rather few tree species occur naturally. It is shown that no other desert tree has as pervasive an influence upon the soil's physical, chemical, biological, and moisture properties; the sub-canopy microclimate; the neighbouring vegetation; and the wildlife and insect populations. The huarango integrates diverse parts of the desert ecosystem. In modifying the environmental extremes characteristic of deserts, especially one as arid as the Peruvian south coast, Prosopis makes what would otherwise be inhospitable lands habitable for other species, including humankind. In other words, if we are to lay bare the ecological consequences of deforestation on the south coast, we need to understand why, here, the huarango is what ecologists term a ‘keystone species’.

Author(s):  
David Beresford-Jones

This book began with the archaeology of the Ullujaya and Samaca basins of the lower Ica Valley on the south coast of Peru. The archaeological investigations described here were undertaken to answer the following questions. Were these basins ever significantly more productive and vegetated landscapes? If so, when and how did change take place, and why? And how did these ecological and landscape changes correlate with cultural ones? The second part of the book conducted a thorough review of the botanical and agroforestry literature, together with the researchers' own observations, on the ecological keystone species of the region, the huarango — a tree of the genus Prosopis — to show how important a role this genus plays in the desert ecosystem of the south coast of Peru. This concluding chapter seeks to achieve a synthesis between these two parts to offer answers to those aforementioned questions posed by today's austere landscape of the lower Ica Valley. In so doing, it proposes a model for geomorphological, ecological, and land-use changes through time for the basins of the lower Ica Valley. It also aims to relate this model to cultural trajectories.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Carl L. Rosier ◽  
Shawn W. Polson ◽  
Vincent D’Amico ◽  
Jinjun Kan ◽  
Tara L. E. Trammell

AbstractThe soil microbial community (SMC) provides critical ecosystem services including organic matter decomposition, soil structural formation, and nutrient cycling. Studies suggest plants, specifically trees, act as soil keystone species controlling SMC structure via multiple mechanisms (e.g., litter chemistry, root exudates, and canopy alteration of precipitation). Tree influence on SMC is shaped by local/regional climate effects on forested environments and the connection of forests to surrounding landscapes (e.g., urbanization). Urban soils offer an ideal analog to assess the influence of environmental conditions versus plant species-specific controls on SMC. We used next generation high throughput sequencing to characterize the SMC of specific tree species (Fagus grandifolia [beech] vs Liriodendron tulipifera [yellow poplar]) across an urban–rural gradient. Results indicate SMC dissimilarity within rural forests suggests the SMC is unique to individual tree species. However, greater urbanization pressure increased SMC similarity between tree species. Relative abundance, species richness, and evenness suggest that increases in similarity within urban forests is not the result of biodiversity loss, but rather due to greater overlap of shared taxa. Evaluation of soil chemistry across the rural–urban gradient indicate pH, Ca+, and organic matter are largely responsible for driving relative abundance of specific SMC members.


2021 ◽  
Vol 13 (12) ◽  
pp. 6660
Author(s):  
Marco Ferrante ◽  
Anuma Dangol ◽  
Shoshana Didi-Cohen ◽  
Gidon Winters ◽  
Vered Tzin ◽  
...  

Vachellia (formerly Acacia) trees are native to arid environments in Africa and the Arabian Peninsula, where they often support the local animal and plant communities acting as keystone species. The aim of this study was to examine whether oil pollution affected the central metabolism of the native keystone trees Vachellia tortilis (Forssk.) and V. raddiana (Savi), as either adults or seedlings. The study was conducted in the Evrona Nature Reserve, a desert ecosystem in southern Israel where two major oil spills occurred in 1975 and in 2014. Leaf samples were collected to analyze the central metabolite profiles from oil-polluted and unpolluted adult trees and from Vachellia seedlings growing in oil-polluted and unpolluted soils in an outdoor setup. We found that oil pollution had a stronger effect on one-year-old seedlings than on adult trees, reducing the levels of amino acids, sugars, and organic acids. While adult trees are mildly affected by oil pollution, the effects on young seedlings can cause a long-term reduction in the population of these keystone desert trees, ultimately threatening this entire ecosystem.


Plant Ecology ◽  
2021 ◽  
Author(s):  
Emma-Liina Marjakangas ◽  
Otso Ovaskainen ◽  
Nerea Abrego ◽  
Vidar Grøtan ◽  
Alexandre A. de Oliveira ◽  
...  

AbstractSpecies co-occurrences in local communities can arise independent or dependent on species’ niches. However, the role of niche-dependent processes has not been thoroughly deciphered when generalized to biogeographical scales, probably due to combined shortcomings of data and methodology. Here, we explored the influence of environmental filtering and limiting similarity, as well as biogeographical processes that relate to the assembly of species’ communities and co-occurrences. We modelled jointly the occurrences and co-occurrences of 1016 tropical tree species with abundance data from inventories of 574 localities in eastern South America. We estimated species co-occurrences as raw and residual associations with models that excluded and included the environmental effects on the species’ co-occurrences, respectively. Raw associations indicate co-occurrence of species, whereas residual associations indicate co-occurrence of species after accounting for shared responses to environment. Generally, the influence of environmental filtering exceeded that of limiting similarity in shaping species’ co-occurrences. The number of raw associations was generally higher than that of the residual associations due to the shared responses of tree species to the environmental covariates. Contrary to what was expected from assuming limiting similarity, phylogenetic relatedness or functional similarity did not limit tree co-occurrences. The proportions of positive and negative residual associations varied greatly across the study area, and we found a significant tendency of some biogeographical regions having higher proportions of negative associations between them, suggesting that large-scale biogeographical processes limit the establishment of trees and consequently their co-occurrences.


2022 ◽  
Vol 503 ◽  
pp. 119789
Author(s):  
Alex Josélio Pires Coelho ◽  
Pedro Manuel Villa ◽  
Fabio Antônio Ribeiro Matos ◽  
Gustavo Heringer ◽  
Marcelo Leandro Bueno ◽  
...  

2011 ◽  
Vol 11 (4) ◽  
pp. 373-376 ◽  
Author(s):  
Raul Costa-Pereira ◽  
Francisco Severo-Neto ◽  
Tamires Soares Yule ◽  
Ana Paula Tinti Pereira

The role of fish as frugivorous and its ecological consequences are often neglected in ecological studies. However, the importance of the interaction between fish and plants is gaining force in scientific literature, and fish has been considered effective seed dispersers. The fruit-eating fish assemblage of Banara arguta (Salicaceae) was evaluated in Southern Pantanal wetlands. Nine species were reported consuming fruits, with different strategies to capture them. The distribution of B. arguta associated with the Pantanal floodplain and the presence of several species of fruit-eating fish, suggest that ichthyochory can be an important seed dispersal strategy to B. arguta.


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