scholarly journals Marine Subsidies Produce Cactus Forests on Desert Islands

2021 ◽  
Author(s):  
Benjamin Wilder ◽  
Amanda Becker ◽  
David Dettman
Keyword(s):  
Gulf Of California ◽  
Terrestrial Ecosystems ◽  
Stable Isotope Ratio ◽  
Plant Production ◽  
Nutrient Cycle ◽  
Allochthonous Input ◽  
Terrestrial Plant ◽  
San Pedro ◽  
Marine Subsidies ◽  
Seabird Guano

Abstract Marine nutrient subsidies can shape terrestrial plant biodiversity. In island systems, nitrogen-rich seabird guano is a large component of such marine subsidies. In zones of nutrient upwelling such as the Gulf of California, copious seabird guano is commonplace on bird islands. Several bird islands host regionally unique cactus forests, especially of the large columnar cactus, cardón (Pachycereus pringlei). We propose that a chain of interactions across the land-sea interface yields an allochthonous input of nitrogen in the form of seabird guano, fueling the production of some of the densest cactus populations in the world. Fish, seabird, guano, soil, and cactus samples were taken from Isla San Pedro Mártir for nitrogen stable isotope ratio measurements, which were compared to soil and cactus samples from other seabird and non-seabird Gulf islands and terrestrial ecosystems throughout the range of the cardón. Isla San Pedro Mártir δ15N values of the food/nutrient cycle are distinctively high, ranging from fish +17.7, seabird +19.7, guano +14.8, soil +34.3 and cactus +30.3. These δ15N values are among the highest ever reported for plants. Seabird island soil and cactus δ15N values were consistently enriched relative to mainland and non-bird islands. Our findings demonstrate that seabird mediated marine nutrient deposits provide the source for solubilized N on desert islands, which stimulate terrestrial plant production in the cardón cactus significantly beyond that seen in either mainland ecosystems or non-seabird islands. These results elucidate the integral nature of nutrient movement across the land-sea interface.

Rock magnetic characterization and paleomagnetic directional analysis of Isla San Pedro Nolasco dikes, Gulf of California, Mexico

2021 ◽  
Vol 83 (8) ◽  
Author(s):  
Luis M. Alva-Valdivia ◽  
Jesús R. Vidal-Solano ◽  
Luis A. Velderrain-Rojas ◽  
José A. González-Rangel
Keyword(s):  
Gulf Of California ◽  
Magnetic Characterization ◽  
San Pedro ◽  
Directional Analysis

scholarly journals Tracking data and retrospective analyses of diet reveal the consequences of loss of marine subsidies for an obligate scavenger, the Andean condor

2018 ◽  
Vol 285 (1879) ◽  
pp. 20180550 ◽  
Author(s):  
Sergio A. Lambertucci ◽  
Joan Navarro ◽  
José A. Sanchez Zapata ◽  
Keith A. Hobson ◽  
Pablo A. E. Alarcón ◽  
...  
Keyword(s):  
Marine Mammals ◽  
Foraging Ecology ◽  
Average Distance ◽  
Isotope Analysis ◽  
Terrestrial Ecosystems ◽  
Mountain Range ◽  
Marine Subsidies ◽  
Nesting Sites ◽  
Foraging Pattern ◽  
Andean Condor

Over the last century, marine mammals have been dramatically reduced in the world's oceans. We examined evidence that this change caused dietary and foraging pattern shifts of the Andean condor ( Vultur gryphus ) in Patagonia. We hypothesized that, after the decrease in marine mammals and the increase in human use of coastlines, condor diet changed to a more terrestrial diet, which in turn influenced their foraging patterns. We evaluated the diet by means of stable isotope analysis ( δ 13 C, δ 15 N and δ 34 S) of current (last decade) and historical (1841–1933) feathers. We further evaluated the movement patterns of 23 condors using satellite tracking of individuals. Condors reduced their use of marine-derived prey in recent compared with historical times from 33 ± 13% to less than 8 ± 3% respectively; however, they still breed close to the coast. The average distance between the coast and nests was 62.5 km, but some nests were located close to the sea (less than 5 km). Therefore, some birds must travel up to 86 km from nesting sites, crossing over the mountain range to find food. The worldwide reduction in marine mammal carcasses, especially whales, may have major consequences on the foraging ecology of scavengers, as well as on the flux of marine inputs within terrestrial ecosystems.

scholarly journals Global meta-analysis shows pervasive phosphorus limitation of aboveground plant production in natural terrestrial ecosystems

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Enqing Hou ◽  
Yiqi Luo ◽  
Yuanwen Kuang ◽  
Chengrong Chen ◽  
Xiankai Lu ◽  
...  
Keyword(s):  
Meta Analysis ◽  
Terrestrial Ecosystems ◽  
Phosphorus Limitation ◽  
Plant Production

Presence of Dosidicus gigas paralarvae (Cephalopoda: Ommastrephidae) in the central Gulf of California, Mexico related to oceanographic conditions

2010 ◽  
Vol 91 (4) ◽  
pp. 807-814 ◽  
Author(s):  
Susana Camarillo-Coop ◽  
César A. Salinas-Zavala ◽  
Marlenne Manzano-Sarabia ◽  
Eugenio Alberto Aragón-Noriega
Keyword(s):  
Gulf Of California ◽  
Mantle Length ◽  
Dosidicus Gigas ◽  
Potential Fecundity ◽  
San Pedro ◽  
Jumbo Squid ◽  
Ecological Importance ◽  
Santa Rosalia ◽  
First Time ◽  
The Relationship

The jumbo squid Dosidicus gigas is the only ommastrephid commercially caught in Mexico. Despite the economic and ecological importance of this species, little is known about its early life stages. The relationship between the presence of paralarvae and mesoscale oceanic features was investigated for the first time in the central Gulf of California, Mexico in February, April, June and September of 2008. A total of 86 paralarvae were found only in June and September (summer season), in the well-stratified column water where the thermocline was evident and warm sea surface waters (27.7° to 29.4°C) dominated. The greatest abundance of D. gigas paralarvae was observed within 2.23 to 3.48 km of the main front. The mantle length of the smallest paralarvae corresponded with the mantle length at hatching. The San Pedro Mártir Island–Santa Rosalia transect and Santa Rosalia–Guaymas transect were determined as the main hatching localities in June and September respectively. The number of paralarvae found in this study contrast with the potential fecundity of mature females which are found throughout the year.

scholarly journals Global signal of top-down control of terrestrial plant communities by herbivores

2018 ◽  
Vol 115 (24) ◽  
pp. 6237-6242 ◽  
Author(s):  
Shihong Jia ◽  
Xugao Wang ◽  
Zuoqiang Yuan ◽  
Fei Lin ◽  
Ji Ye ◽  
...  
Keyword(s):  
Plant Communities ◽  
Meta Analysis ◽  
Terrestrial Ecosystems ◽  
Global Scale ◽  
Basic Site ◽  
Plant Interactions ◽  
Top Down ◽  
Plant Abundance ◽  
Terrestrial Plant ◽  
Positive Effects

The theory of “top-down” ecological regulation predicts that herbivory suppresses plant abundance, biomass, and survival but increases diversity through the disproportionate consumption of dominant species, which inhibits competitive exclusion. To date, these outcomes have been clear in aquatic ecosystems but not on land. We explicate this discrepancy using a meta-analysis of experimental results from 123 native animal exclusions in natural terrestrial ecosystems (623 pairwise comparisons). Consistent with top-down predictions, we found that herbivores significantly reduced plant abundance, biomass, survival, and reproduction (allP< 0.01) and increased species evenness but not richness (P= 0.06 andP= 0.59, respectively). However, when examining patterns in the strength of top-down effects, with few exceptions, we were unable to detect significantly different effect sizes among biomes, based on local site characteristics (climate or productivity) or study characteristics (study duration or exclosure size). The positive effects on diversity were only significant in studies excluding large animals or located in temperate grasslands. The results demonstrate that top-down regulation by herbivores is a pervasive process shaping terrestrial plant communities at the global scale, but its strength is highly site specific and not predicted by basic site conditions. We suggest that including herbivore densities as a covariate in future exclosure studies will facilitate the discovery of unresolved macroecology trends in the strength of herbivore–plant interactions.

History of Scientific Exploration in the Sea of Cortés

2002 ◽  
Author(s):  
George E. Lindsay ◽  
Iris H. W. Engstrand
Keyword(s):  
Gulf Of California ◽  
Ecological Change ◽  
Imperial Valley ◽  
Scientific Exploration ◽  
San Pedro ◽  
San Marcos ◽  
History Of ◽  
Sea Of Cortes ◽  
Western Side ◽  
Well Differentiated

The Sea of Cortés (el Mar de Cortés), also known as the Gulf of California, is the body of water that separates the California peninsula from the mainland of Mexico. It extends in a northwest-southeast axis for 1070 km, varying in width from 100 to 200 km. The gulf was formerly much longer, but sediments carried by the Colorado River created a delta and dammed off its upper end, forming what is now the Imperial Valley. The western side of the gulf is dotted with islands, the longest of which is Ángel de la Guarda, measuring 67 km long, up to 16 km wide, and 1315 m high (see app. 1.1 for a list of island names and measurements). Most of the islands are geological remnants of the peninsula's separation from the mainland, a continuing process that started 4 or more million years ago. One central gulf island, Tortuga, is an emerged volcano, whereas San Marcos Island to its west is largely gypsum, possibly precipitated from an ancient lake. The largest island in the gulf is Tiburón, with an area of approximately 1000 km2. It is barely separated from the mainland to the east and has a curiously mixed biota of peninsular and mainland species. One tiny island, San Pedro Nolasco, is only 13 km off shore in San Pedro Bay, Sonora, but has an unusual flora that includes a high percentage of endemics. The isolation of organisms that colonized or were established previously on the Sea of Cortés islands provided an opportunity for genetic and ecological change. In one plastic and rapidly evolving plant family, the Cactaceae, about one-half of the 120 species found on the islands are endemic. Similarly, populations isolated by climate on peninsular mountains are well differentiated. Because of the topographical diversity of the area and its effect on the disruption and integration of populations, the Sea of Cortes and its islands have been called a natural laboratory for the investigation of speciation.

Spawning by jumbo squid Dosidicus gigas in San Pedro Mártir Basin, Gulf of California, Mexico

2006 ◽  
Vol 313 ◽  
pp. 125-133 ◽  
Author(s):  
WF Gilly ◽  
CA Elliger ◽  
CA Salinas ◽  
S Camarilla-Coop ◽  
G Bazzino ◽  
...  
Keyword(s):  
Gulf Of California ◽  
Dosidicus Gigas ◽  
San Pedro ◽  
Jumbo Squid

scholarly journals Spatio-Temporal Variation in AOD and Correlation Analysis with PAR and NPP in China from 2001 to 2017

2020 ◽  
Vol 12 (6) ◽  
pp. 976 ◽  
Author(s):  
Xin Li ◽  
Hongyu Liang ◽  
Weiming Cheng
Keyword(s):  
Net Primary Productivity ◽  
Negative Impact ◽  
Positive Impact ◽  
Ground Surface ◽  
Terrestrial Ecosystems ◽  
Temporal Variations ◽  
Plant Production ◽  
Positive Correlation ◽  
Increasing Trend ◽  
Spatio Temporal

Atmospheric aerosols can elicit variations in how much solar radiation reaches the ground surface due to scattering and absorption, which may affect plant photosynthesis and carbon uptake in terrestrial ecosystems. In this study, the spatio-temporal variations in aerosol optical depth (AOD) are compared with that in photosynthetically active radiation (PAR) and net primary productivity (NPP) during 2001–2017 in China using multiple remote sensing data. The correlations between them are analyzed at different scales. Overall, the AOD exhibited a northeast-to-southwest decreasing pattern in space. A national increasing trend of 0.004 year−1 and a declining trend of −0.007 year−1 of AOD are observed during 2001–2008 and 2009–2017. The direct PAR (PARdir) and diffuse PAR (PARdif) present consistent and opposite tendency with AOD during two periods, respectively. The total PAR (PARtotal) shows a similar variation pattern with PARdir. In terms of annual variation, the peaks of AOD coincide with the peaks of PARdif and the troughs of PARdir, indicating that aerosols have a significant positive impact on PARdir and a negative impact on PARdif. Furthermore, the PARdir has a stronger negative association with AOD than the positive correlation between PARdif and AOD at national and regional scales, indicating that PARdir is more sensitive to aerosol changes. The NPP has higher values in the east than in the west and exhibits a significant increasing trend of 0.035 gCm−2day−1 after 2008. The NPP has a negative correlation (−0.4–0) with AOD and PARdif and a positive correlation (0–0.4) with PARdir in most areas of China. The area covered by forests has the highest NPP-PAR correlation, indicating that NPP in forests is more sensitive to the PAR than is the NPP in grasslands and croplands. This study is beneficial for interpreting the aerosol-induced PAR impact on plant growth and for predicting plant production on haze days.

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