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opencc-by-4.0Nov 2024View details →

Seasonal orographic effect of North American Mountain Range at different levels and its remote control on tropical climate

<a name="OLE_LINK36"></a><a name="OLE_LINK37"></a><a name="OLE_LINK81"></a><a name="OLE_LINK6"></a>Orography significantly influences global climate patterns. <a name="OLE_LINK32"></a><a name="OLE_LINK33"></a>Previous studies show the North American Mountain Range (NAMR) impacts regional climates seasonally but have not thoroughly illustrated the seasonally different atmospheric responses in the lower and upper troposphere, respectively. Using the Community Earth System Model version 1.2 with a slab ocean configuration, we investigate the NAMR’s seasonal impacts by simulating scenarios with and without the mountain range. Our findings reveal that the NAMR induces contrasting responses in sea surface temperature (SST) and precipitation off California in different seasons, indicating different underlying mechanisms. Through analysis of large-scale circulation and local energy budgets, we find that in summer, the NAMR reinforces the North Pacific High causing SST cooling and drying off California. This cooling propagates to the equatorial Pacific via anomalous northeasterlies, influencing the Intertropical Convergence Zone and initiating a climatic signal through the Pacific Meridional Mode, which crosses the equator and affects Southern Hemisphere temperatures. In winter, the NAMR reduces wind speed and evaporation, leading to SST warming off California, amplified by SST-cloud feedback. In the upper troposphere, we observe seasonal shifts in jet stream patterns: during winter, a weakened, equatorward-shifted jet over the Pacific and a strengthened, poleward-shifted branch over the Atlantic; in summer, the jet stream intensifies over and downstream of the mountains while weakening upstream. Our research highlights distinct seasonal mechanisms by which the NAMR influence climate patterns, linking mid-latitude climate variations to equatorial, cross-hemispheric and global changes.

opencc-by-4.0Jan 2022View details →

Data set: Land use and land cover change in a tropical mountain landscape of northern Ecuador: altitudinal patterns and driving forces

Tropical mountain ecosystems are threatened by land use pressures, compromising their capacity to provide multiple ecosystem services. The analysis of landscape changes and their proximate driving forces is often qualitative and sectorial oriented, although local patterns and numerous interactions among socio-economic, demographic, and biophysical factors shape these socio-ecological systems. We characterized land use land cover (LULC) dynamics using Markov-chain probabilities by elevation and geographic settings and then, implementing the DPSIR holistic approach, we integrated them with a variety of freely available geospatial and temporal data into a Generalized Additive Model (GAM) to uncover the factors driving such landscape dynamics in a sensitive region of the northern Ecuadorian Andes. Our results demonstrated a dynamic and clear geographical pattern of distinct LULC transitions through time, explained by different combination of socio-economic factors, demographic and infrastructure variables and environmental parameters, from which topographic variables were the main drivers of change in this landscape. We found that deforestation of remnant native forest and agricultural expansion still occur in higher elevations, while land conversion toward anthropic environments, particularly significant expansion of floriculture and urban areas were observed in lower elevations to the east of the studied territory. Our findings also revealed an unexpected stability trend of paramo and a successional recovery of previous agricultural land to the west and center of the territory, which could be explained by agricultural land abandonment. However, the very low probability of persistence of montane forests found overall, highlights the greater threat to permanently lose the already vulnerable mountain native biodiversity. The methodological approach and our findings, demonstrating dynamic patterns through space and time and their explanatory drivers, could help local authorities and stakeholder to improve sustainably resource land management in vulnerable landscapes such as the tropical Andes in northern Ecuador.

opencc-by-4.0Apr 2024View details →

Triple oxygen isotope variability of precipitation in a tropical mountainous region

Triple oxygen isotope data associated with monthly integrated precipitation and discrete (subsurface-sourced) tap water samples collected over one year from sites across Panama.

opencc-by-4.0Dec 2009View details →

Fig. 3 in How does diet influence the reproductive seasonality of tropical freshwater fish? A case study of a characin in a tropical mountain river

Fig. 3. Non-Metric Multi-Dimensional Scaling Ordination (NMDS) of monthly variations of the diet with respect to sex. Stress = 0.10. Filled symbols are the dry months.

opencc-by-4.0Dec 2009View details →

Fig. 2 in How does diet influence the reproductive seasonality of tropical freshwater fish? A case study of a characin in a tropical mountain river

Fig. 2. Monthly variation of prey types-IRI values. Rainfall follows a bimodal seasonal pattern (shadow on background). The asterisks show the months in which reproduction occurs.

opencc-by-4.0Dec 2009View details →

Fig. 1 in How does diet influence the reproductive seasonality of tropical freshwater fish? A case study of a characin in a tropical mountain river

Fig. 1. Ontogenetic and intersexual variation in the diet of Creagrutus guanes. Size classes correspond to standard length ranges: 3 = 21-30 mm; 4 = 31-40 mm; 5 = 41-50 mm; 6 = 51-60 mm; 7 = 61-70mm; 8 = 71-80mm.

Fig. 2 in Reproductive seasonality of Geophagus steindachneri Eigenmann & Hildebrand, 1922 (Perciformes: Cichlidae) in a tropical mountain river

Fig. 2. Monthly variation in adult females: (a) SL, standard length and WE, eviscerated weight, (b) liver and fat weight, and (c) ovary weight. Barplot behind the lines represents the rainfall pattern.

Fig. 5 in Reproductive seasonality of Geophagus steindachneri Eigenmann & Hildebrand, 1922 (Perciformes: Cichlidae) in a tropical mountain river

Fig. 5. Monthly variation in adult males: (a) SL, standard length and WE, eviscerated weight, (b) liver and fat weight, and (c) testis weight. Barplot behind the lines represents the rainfall pattern.

Fig. 3 in Reproductive seasonality of Geophagus steindachneri Eigenmann & Hildebrand, 1922 (Perciformes: Cichlidae) in a tropical mountain river

Fig. 3. Monthly variation in (a) the frequency of ovarian development stages and (b) the frequency of mouthbrooding females carrying embryos, larvae, or juveniles.

Fig. 1 in Reproductive seasonality of Geophagus steindachneri Eigenmann & Hildebrand, 1922 (Perciformes: Cichlidae) in a tropical mountain river

Fig. 1. Monthly variation of environmental variables: (a) rainfall pattern, (b) pH and temperature, and (c) conductivity and transparency.

Fig. 4 in Reproductive seasonality of Geophagus steindachneri Eigenmann & Hildebrand, 1922 (Perciformes: Cichlidae) in a tropical mountain river

Fig. 4. Differences between females that were not performing parental care and mouth-brooding females: (a) stage of ovary maturity, with circle size indicating number of females in each condition; (b) liver and ovary weight.

opencc-by-4.0Jun 2024View details →

Figure 1 in Limited thermal plasticity in high mountain tropical water bears

Figure 1. The environmental temperature is depicted in black while the moss temperature is shown in green. Temperatures were recorded every minute from October 18th to November 16th, 2023. Throughout the day, temperatures were not stable. The average environmental temperature was 14.7 °C, ranging from a minimum of 9.3 °C to a maximum of 25.6 °C. The average moss temperature was 14.6 °C, ranging from a minimum of 9.6 °C to a maximum of 23.1 °C.

Fig. A3 in Susceptibility of tropical mountain forests to biological invasions from the temperate and subtropical zone, exemplified by Zonitoides (Gastropoda: Gastrodontidae)

Fig. A3. Map of the occurrences of Zonitoides arboreus s.l. and Zonitoides nitidus used for the calculation of climatic suitability for the 20 km grid resolution.

Fig. A4 in Susceptibility of tropical mountain forests to biological invasions from the temperate and subtropical zone, exemplified by Zonitoides (Gastropoda: Gastrodontidae)

Fig. A4. Global climatic suitability for: (a) Zonitoides arboreus s.l.; and (b) Zonitoides nitidus based on Mahalanobis distances using the 20 km grid resolution. The higher the threshold, the more dissimilar are the climatic conditions to those of the majority of known occurrences, and>100% means that the climatic conditions are dissimilar to those of any other available record. Please note that the deserts of Africa, Arabia and Australia are unlikely places for a snail that inhabits (temperate) forests in its native range (Z. arboreus s.l.), and that the Great Lakes Region that seems well inhabited by Z. nitidus does not fully match its climate, what can only be explained from effects of averaging local climates at a larger grid scale.

Fig. A1 in Susceptibility of tropical mountain forests to biological invasions from the temperate and subtropical zone, exemplified by Zonitoides (Gastropoda: Gastrodontidae)

Fig. A1. Map of the occurrences of Zonitoides arboreus s.l. used for the calculation of climatic suitability for the 10 km grid resolution.

Fig. 4 in Susceptibility of tropical mountain forests to biological invasions from the temperate and subtropical zone, exemplified by Zonitoides (Gastropoda: Gastrodontidae)

Fig. 4. Position of the new locations (L1 and L2, enumeration for each species separately) in Sabah in relation to the Mahalanobis distances of climatic variables for: (a) Zonitoides arboreus s.l., and (b) Z. nitidus. Record ID refers to the order of the data entry.

Fig. 2 in Susceptibility of tropical mountain forests to biological invasions from the temperate and subtropical zone, exemplified by Zonitoides (Gastropoda: Gastrodontidae)

Fig. 2. Global climatic suitability for (a) Zonitoides arboreus s.l. and (b) Zonitoides nitidus based on Mahalanobis distances from the 10 km grid resolution. The higher the threshold, the more dissimilar are the climatic conditions to those of the majority of known occurrences, and>100 % means that the climatic conditions are dissimilar to those of any other available record.

Fig. 1 in Susceptibility of tropical mountain forests to biological invasions from the temperate and subtropical zone, exemplified by Zonitoides (Gastropoda: Gastrodontidae)

Fig. 1. Estimation of the phylogenetic relationships of the COI barcoding sequence from the Zonitoides specimens and two outgroups (labeled with their BOLD or GenBank accession numbers) using the Maximum Likelihood method based on the Tamura-Nei model. The tree with the highest log likelihood (−2138.3583) is shown. Branch lengths equal genetic distances in terms of the number of base substitutions per site. The percentage of replicate trees in which the associated taxa clustered together in the bootstrap test (500 replicates) are shown next to the branches. The tree was constructed in MEGA 6.0. Please note that the shell of (living) Z. nitidus is darkly pigmented, and that the extended animal of the depicted Z. nitidus started fading.

Fig. A2 in Susceptibility of tropical mountain forests to biological invasions from the temperate and subtropical zone, exemplified by Zonitoides (Gastropoda: Gastrodontidae)

Fig. A2. Map of the occurrences of Zonitoides nitidus used for the calculation of climatic suitability for the 10 km grid resolution.