Soil Quality Restoration during the Natural Succession of Abandoned Cattle Pastures in Deforested Landscapes in the Colombian Amazon

Successional processes in abandoned pastures in the Amazon region have been well-documented for the floristic component; however, soil succession has been poorly studied. This study assessed the physical, chemical and biological responses of soils in the Amazon region during the natural succession process in two main landscapes of the Colombian Amazon. Soil data on soil physico–chemical (bulk density, macroaggregates, pH and minerals) and biological (soil macrofauna) composition were evaluated along chronosequence with four successional stages: (i) degraded pastures, (ii) young (10–20-year-old), (iii) middle-age (25–40-year-old) and (iv) mature forests, in two different landscapes (hill and mountain). Individual soil variables and a synthetic indicator of soil quality (GISQ) were evaluated as tools for natural succession monitoring. The results corroborated the negative impact that cattle ranching has on Amazon soils. After 10 years of natural succession, the physico–chemical and biological soil components were widely restored. Less soil compaction and organic carbon occurred in older successional stages. Soil macrofauna richness and density increased along the chronosequence, with an evident association between the macrofauna composition and the macroaggregates in the soil. None of the individual soil properties or the GISQ indicator discriminated among natural succession stages; therefore, new soil quality indicators should be developed to monitor soil quality restoration in natural successions.

Structure, composition and carbon stocks of woody plant community in assisted and unassisted ecological succession in a Tamaulipan thornscrub, Mexico

Background Ecological restoration is a process that helps the recovery of an ecosystem that has been degraded, damaged or destroyed. The success of restoration actions depend on the understanding of the processes, mechanisms and factors that guide vegetation dynamics. The restoration of plant communities can be made by unassisted (passive restoration, where the community recover by itself) and assisted (active restoration) ecological succession. It is imperative to know the scope of both types of activities to guide future restoration actions by evaluating the properties and functioning of the intervened communities. Methods Variance analysis of the carbon (C) stocks, basal area, canopy area, Shannon–Weaver index values, specific richness and abundance of three Tamaulipan thornscrub communities (assisted natural succession area, unassisted natural succession area and control area) was performed. Furthermore, a similarity analysis between the sampling areas using the floristic composition (abundance) was performed. Results In total, 11 families, 17 genera and 20 species of vascular plants were registered. The richness of species and abundance ranked as follows per area: assisted ecological natural succession > control > unassisted ecological natural succession. The species composition between sampling areas showed a low number of common species between plant communities. Conclusions The values of species richness, diversity, abundance, basal area, and canopy area of the assisted natural succession vegetal community was statistical similar to the control plan community. The values of C stocks showed that assisted ecological succession could recover not only structure and composition attributes but also this key ecosystem property.

Rapid Reclamation and Degradation of Suaeda salsa Saltmarsh Along Coastal China’s Northern Yellow Sea

Suaeda salsa saltmarshes are an important coastal wetland habitat of China’s northern Yellow Sea, which plays a critical role in sequestering carbon (blue carbon), protecting shorelines, maintaining biodiversity, and has substantial economic value (e.g., ecotourism). However, the area of S. salsa has been rapidly declining due to several different threats from reclamation and invasive species that impact its natural succession. Here, we map the changes in the distribution of the S. salsa saltmarshes along the northern Yellow Sea of China (NYSC) at 5-year intervals by applying the supervised maximum likelihood method to analyze Landsat images from 1988 to 2018 and investigate the potential impact of three important factors on habitat change by analyzing the temporal changes in S. salsa saltmarshes with other land covers. S. salsa saltmarsh areas have decreased by 63% (264 km2 ha to 99 km2), and the average loss of S. salsa saltmarshes was 5.5 km2/year along the NYSC over the past three decades. There have been many dramatic declines in the two main distribution areas of S. salsa saltmarshes with a 77% loss of habitat area in Liaodong Bay (from 112 km2 to 26 km2) and a 52% loss in the Yellow River Delta wetland-Guangli-Zhima estuarine wetland (from 137 km2 to 65 km2). Land reclamation is the most important impact factor in the loss of S. salsa saltmarshes, while there have been limited effects of natural succession and smooth cordgrass (Spartina alterniflora) invasion. In light of the important ecological services and economic value of the S. salsa habitat, emergency conservation actions (e.g., habitat restoration, strictly supervision) are needed to limit the rapid habitat loss, which should include the immediate cessation of extensive land reclamation along the NYSC.

Butterflies and moths (Insecta: Lepidoptera) of the Lokrum island, southern Dalmatia

In 2016 and 2017 a survey of the butterflies and moth fauna of the island of Lokrum, Dubrovnik was carried out. A total of 208 species were recorded, which, together with 15 species from the literature, raised the total number of known species to 223. The results of our survey can be used as a baseline for the study of future changes in the Lepidoptera composition on the island. In comparison with the literature records, eight butterfly species can be regarded as extinct from the island. The most probable reason for extinction is the degradation of the grassland habitats due to the natural succession as well as the introduction of the European Rabbit and Indian Peafowl. Their presence has probably had a tremendously detrimental effect on the native flora and fauna of the island. To conserve the Lepidoptera fauna of the island, and the still remaining biodiversity, immediate eradication of these introduced species is needed.

Agregação de solo em pastagens sob diferentes índices de qualidade e sua influência na infiltração de água

In Brazil, extensive livestock farming predominates, often in soils with low agricultural potential and susceptible to degradation, mainly in terms of physical aspects and water infiltration. Thus, this work aims to analyze the impact caused by the succession process in soil of different pasture areas, with an emphasis on their physical quality and physical-hydric characteristics, relating them to the role played by naturally observed ecosystem services. For this, 4 grazing areas were selected, in Red Ultisol, under different levels of natural succession: grazing in good visual conditions (PB); pasture under low scrub (CB); pasture under high scrub (CA); pasture under “capoeirão” (CAO), in the Ribeirão José Pereira microbasin (Itajubá - MG). The physical attributes were determined: soil density, porosity, size and stability of aggregates, as well as their classification as to the formation path. The infiltration analysis was carried out with the aid of a Guelph permeameter and the resistance to mechanical penetration of the soil with an impact penetrometer. For analysis of the results, analysis of variance and Tukey test at 5%, Pearson's correlation and multivariate statistics of main components were used. The natural succession in abandoned pastures improves the physical quality of the soil, with the production of larger, more stable aggregates and of biogenic formation over time. The areas could be classified according to their quality, in the following increasing order: PB < CB < CA < CAO, which respected the action of natural succession and, therefore, of ecosystem services.