Influence of scattered trees in grazing areas on soil properties in the Piedmont region of the Colombian Amazon

Trees dispersed in grazing areas are contribute to the sustainability of livestock systems. The interactions between trees and soil are ecological processes that allow the modification of the biology, fertility, and physics of the soil. This study was aimed to assess the influence of dispersed trees in pastures on soil properties in grazing areas for dual-purpose cattle systems in the Piedmont region of the Colombian Amazon. The work was done in grazing areas with scattered trees at the Centro de Investigaciones Amazónicas CIMAZ–Macagual in Florencia—Caquetá—Colombia. We evaluated the effect of five tree species, Andira inermis, Bellucia pentámera, Guarea Guidonia, Psidium guajava and Zygia longifolia, on soil properties (up to 30 cm soil depth) under and outside the influence of the crown. Under the tree crown, three points were systematically taken in different cardinal positions. This was done at a distance corresponding to half the radius of the tree crown. The sampling points in the open pasture area (out of crown) were made in the same way, but at 15 m from the crown border. The ANOVA showed significant interaction (P < 0.0001) between tree species and location for macrofauna abundance up to 30 cm soil depth. For this reason, we performed the comparison between locations for each tree species. Chemical soil variables up to 10 cm soil depth only showed interaction of tree species-location for exchangeable potassium (P = 0.0004). Soil physical soil characteristics up to 30 cm soil depth only showed interaction of tree species-location at 20 cm soil depth (P = 0.0003). The principal component analysis for soil properties explained 61.1% of the total variability of the data with the two first axes. Using Monte Carlo test, we found crown effect for all species. Trees help to control exchangeable mineral elements that can affect the soil, potentiate basic cations such as magnesium and potassium, increase the abundance of soil macrofauna; but some trees with high ground level of shade in grazing areas could increase soil compaction due to the greater concentration of cattle in these areas.

Capturing and Evaluating the Effects of the Expansive Species Ailanthus altissima on Agro-Ecosystems on the Ionian Islands

There is a significant number of agricultural systems with rich and special biodiversity, characterized as high-nature-value farming systems (HNV) in the Ionian Islands region. These agro-ecosystems cover a significant area in this region and are divided in olive groves and vineyards which, in some cases, cover a significant part of the protected areas (Natura 2000 and SPA). There are solid olive groves but also a large number of scattered trees or clusters, as well as vineyards, which are largely identified as high-quality wine producers. Finally, there are smaller but extremely important examples of HNV, such as the Englouvi plateau in Lefkada. In this study, we propose a method to survey the spread of Ailanthus altissima in olive groves and vineyards (HNV areas) with the scope of evaluating the considered agro-ecosystems, based on the importance of ecosystems and ecosystem services they provide, and preparing a management plan for HNV areas.

Effects of scattered Faidherbia albida and Cordia africana Tree on Soil Properties under their Canopies in Fedis District, Easte Hararghe Zone, Oromia

The study was conducted to investigate the effect of scattered trees under their canopies on soil fertility status at Fedis district, East Hararghe Zone, oromia, Ethiopia. Accordingly, six isolated and nearly identical Faidherbia albida and Cordia africana trees were selected and the canopy coverage of each tree was divided into four radial transects. Soil samples from three horizontal distances levels: 2.5m, 5m and 25m with two soil depths levels (0–20cm and 20-40cm) were taken for analysis of soil physical and chemical properties and tree species with two levels with factorial arrangement in RCBD replicated six times were employed. The result revealed soil texture was not influenced significantly (P>0.05) by tree species. Soil bulk density was significantly (p<0.05) influenced by both tree species. Soil moisture was significantly (p<0.05) higher under canopy of trees than open field and in surface than in subsurface soils. Soil chemical properties;- electric conductivity, organic carbon, organic matter, soil carbon stock, total nitrogen, available phosphorus and exchangeable cation (Mg, Ca, Na and K) for surface and subsurface soil layers of under F.albida and C. africana trees were significantly (p<0.05) higher in canopy than open field and in surface than subsurface. Soil pH was not significantly (p>0.05) influenced by both tree species. It can be concluded that these tree species have the potential to improve soil fertility beneath its canopy. This may be important for the agricultural landscape health and demonstrated the scattered trees to retain on crop fields to improve soil fertility status under its canopy and on farm biodiversity conservation in agricultural landscapes conditions.

Scattered Trees as Crucial Elements in Maintaining Urban Diversity: A Case Study with Canopy ants in a Biodiversity Hotspot

Urban environments are under a high degree of human disturbance, which profoundly changes their abiotic characteristics, affecting the biotic communities. A conspicuous element in cities are scattered trees, often included in urban planning around the world. These trees are key elements for urban ecological processes and services and act as islands of resources (i.e., food and shelter) for a considerable arthropod’s diversity, such as ants. Studies involving ants in urban environments often focus on ground-dwelling ants, and few studies seek to glimpse the ants that occupy scattered trees and, even less, how these ants and trees interact within cities. This study aimed to investigate the ant communities foraging day and night on trees in an urban area inside a biodiversity hotspot, the Brazilian Atlantic Forest. Specifically, we investigated how tree characteristics (tree size, tree isolation, presence of extrafloral nectaries, and the tree origin, i.e., native and exotic) modulate ant diversity and ant-plant interactions. We found that the species composition is different between day and night, as well as the central core of generalist ant species of day and night interaction networks. The tree size increases beta-diversity among trees only of the nocturnal ant community, while none of the tree characteristics shaped the ant community. This study is the first to address the role of scattered trees in maintaining the diversity of arboreal ants in urban landscapes, focusing on species diversity and their interaction networks. Overall, we provide insights supporting the conservation value of scattered trees in maintaining urban biodiversity.

Terrestrial Medium and Large-Sized Mammalian Species Diversity in Michole Community Protected Forest, Southern Ethiopia

Study on medium and large size mammalian species diversity and distribution is important for conservation efforts in the different protected areas of Ethiopia. The study aimed to assess the species diversity of medium and large-sized mammalian fauna between October 2019 and July 2020 in Michole Community Protected Forest, southern Ethiopia. The study was conducted by stratification of the study area into three habitat types riverine forest (3.37 km2), woodland (4.14 km2), and grassland with scattered trees (2.33 km2) based on the vegetation cover. A diurnal transect survey method was implemented to record the mammalian species diversity. A total of 18 representative sample transect lines (six in riverine forest, four in grassland with scattered trees, and eight in the woodland habitats) which varied in length and width were used. A total of 17 species of medium and large-sized mammalian species were identified and recorded in the study area. Accordingly, order Carnivora and Primates constitutes a large proportion of abundance, while order Lagomorpha was the least. Anubis baboon (Papio anubis) was the most abundant species (15.14%) followed by Spotted hyena (12.98%), Porcupine (12.51%), Vervet monkey (10.35%), Common duiker (8.80%), and Giant root-rat (8.65%). The distributions of mammals among the three habitat types were comparable. Riverine forest harbored the highest mammalian diversity index (H’=2.35) followed by the woodland (H’=2.32), and the grassland with scattered trees (H’=2.30), respectively. The greatest species similarity was recorded in woodland (0.902). The study area harbors considerable mammalian species that are threatened by interacting anthropogenic factors. So, urgent conservation measures by concerned sectors are needed to safeguard these animals and their habitat.

Seasonal SUHI Analysis Using Local Climate Zone Classification: A Case Study of Wuhan, China

The surface urban heat island (SUHI) effect poses a significant threat to the urban environment and public health. This paper utilized the Local Climate Zone (LCZ) classification and land surface temperature (LST) data to analyze the seasonal dynamics of SUHI in Wuhan based on the Google Earth Engine platform. In addition, the SUHI intensity derived from the traditional urban–rural dichotomy was also calculated for comparison. Seasonal SUHI analysis showed that (1) both LCZ classification and the urban–rural dichotomy confirmed that Wuhan’s SHUI effect was the strongest in summer, followed by spring, autumn and winter; (2) the maximum SUHI intensity derived from LCZ classification reached 6.53 °C, which indicated that the SUHI effect was very significant in Wuhan; (3) LCZ 8 (i.e., large low-rise) had the maximum LST value and LCZ G (i.e., water) had the minimum LST value in all seasons; (4) the LST values of compact high-rise/midrise/low-rise (i.e., LCZ 1–3) were higher than those of open high-rise/midrise/low-rise (i.e., LCZ 4–6) in all seasons, which indicated that building density had a positive correlation with LST; (5) the LST values of dense trees (i.e., LCZ A) were less than those of scattered trees (i.e., LCZ B) in all seasons, which indicated that vegetation density had a negative correlation with LST. This paper provides some useful information for urban planning and contributes to the healthy and sustainable development of Wuhan.

Ecological connectivity in fragmented agricultural landscapes and the importance of scattered trees and small patches

Background Fragmentation and habitat loss can restrict species movement and reduce connectivity, negatively impacting biodiversity. Characterising the overall connectivity of an area can inform better management of human modified landscapes. Contemporary connectivity modelling methods seldom incorporate fine-scale movement patterns associated with movement between fine-scaled structural connectivity elements such as scattered trees, roadside corridors and small patches of habitat. This study aims to characterise connectivity within the Karuah-Myall catchments, a typical woodland ecosystem that is fragmented by agriculture, using least-cost path analysis and a graph-theoretic approach; it focuses on how fine-scaled vegetation such as scattered trees support connectivity. We mapped scattered (and paddock) trees within this agricultural landscape where the main human modified land use was pasture. We modelled connectivity for a general representative woodland species using an interpatch dispersal distance and gap crossing threshold, and resistance from different land cover types. The gap crossing distance threshold was used to model movement between fine-scaled vegetation features. We compared the least-cost paths modelled with and without scattered trees. Results Our results show that by excluding scattered trees, least-cost paths across the cleared pasture landscape did not reflect the types of movement patterns typically observed from field studies, such as those associated with a foray-search strategy used by small and medium mammals and birds. The modelling also shows that the Karuah-Myall catchments are well connected and provide value to biodiversity beyond the catchment borders, by connecting coastal vegetation to the Great Eastern Ranges national wildlife corridor initiative. Conclusion Connectivity models that exclude fine-scale landscape features such as scattered trees and small, linear patches risk misrepresenting connectivity patterns. Models of regional-scale connectivity can be influenced by the presence or absence of even the smallest features, such as scattered trees.

Trees Increase Ant Species Richness and Change Community Composition in Iberian Oak Savannahs

Iberian man-made oak savannahs (so called dehesas) are traditional silvopastoral systems with a high natural value. Scattered trees provide shelter and additional food to livestock (cattle in our study sites), which also makes possible for animals depending on trees in a grass-dominated landscape to be present. We compared dehesas with nearby treeless grasslands to assess the effects of oaks on ant communities. Formica subrufa, a species associated with decayed wood, was by far the most abundant species, especially in savannahs. Taxa specialized in warm habitats were the most common both in dehesas and grasslands, as expected in areas with a Mediterranean climate. Within dehesas, the number of species was higher below oak canopies than outside tree cover. Compared to treeless grasslands, the presence of oaks resulted in a higher species richness of aphid-herding and predator ants, probably because trees offer shelter and resources to predators. The presence of oaks changed also the species composition, which differed between grasslands and dehesas. In self-standing scattered oaks, ant communities did not differ between the trunks and soil below canopies. These results stress the conservation value of trees in dehesas; within grasslands, they offer an additional microhabitat for species that would otherwise be scarce or absent.