After many years of collaborative field science, lab experiments and analysis, computer modeling, a chapter of my PhD dissertation, and Lydia and Melissa’s Master’s theses, colleagues and I just published a paper describing the continual decomposition of the soil in Tuolumne Meadows. Today’s plant community isn’t productive enough to maintain the high-carbon content of the soil. There’s lots of bare ground in the meadow and very few sedge plants that we’d expect to see in a place like this with such a carbon-rich soil. We grew and transplanted those expected sedges to see if we could restore carbon balance to the meadow. The plants are surviving and growing strong root systems, but haven’t yet spread and become productive enough to stem the loss of carbon. Reversing years of impact and carbon loss is a slow process in short subalpine summers. I’ll revisit Tuolumne Meadows in a few years to check its carbon pulse. Hopefully I’ll find that the plants are growing strong and building back the decades of lost soil. Newsweek wrote a nice piece summarizing our study.
Happy Darwin Day, 2026
Charles Darwin was born 217 years ago today and he went on to develop the most important concept in biology and ecology: Evolution. I recently listened to a wonderful talk, sponsored by Bay Nature, about the evolution of a weird little animal that I’ve only seen once in the wild, the mountain beaver, Aplodontia rufa. These burrowing rodents live along the margins of Sierra Nevada wetlands and I’ve often seen their tunnels draining water from flooded areas to lower, drier erosion gullies.
Dr. Samantha Hopkins, paleontologist at the University of Oregon, described the fossil evidence for the 40 million year old lineage that has left A. rufa as the only living representative. Dr. Hopkins highlighted one of the odd things about modern mountain beavers: they have no loops of Henle in their kidneys. The loops allow for more concentrated urine and reuse of water. Without the loops, mountain beavers lose a lot of water in their urine and thus have a high water demand. Which is why they hang out near wetlands! Researchers have assumed that this lack of loops is a primitive trait, inherited from a long-extinct ancestor that the Aplodontia line shared with other rodents.
However, Dr. Hopkins’ lab is using isotopic analyses of fossil teeth to show that extinct ancestors probably did possess the ability to concentrate urine, and the lack of loops in modern mountain beavers is not an inherited “primitive” trait, but rather a more recently evolved one. Evolution works in weird and wonderful ways. The water-inefficient kidneys of the mountain beaver probably have some benefit for survival. At the very least, they keep the little animals close to some of the most beautiful places on earth!
World Wetlands Day 2026
Wetlands are wonderful places, as people have known for thousands of years. Their rich soil and abundant water make for excellent crop land, usually once some of the abundance of water has been drained away. At Halstead Meadow, a wetland in Sequoia National Park, a group of crop plants sprouted out from the ashes in patches burned in the 2021 KNP Complex wildfire. These agricultural plants – wheat, sunflower, millet, sorghum, and corn – grew only in the summer of 2022, and only in areas where the KNP fire had burned away the top 4-6 inches of organic wetland soil. The seeds had probably been lying dormant, buried under wetland soil, since they were planted over a century ago before Sequoia National Park existed. Back then a cattleman named Sam Halstead had used this meadow for grazing, and apparently for growing a few crops! I collected leaf and seed samples from each of these plants and they’re sitting in my freezer. I’m hoping to find a expert in crop varieties who would be willing to analyze the genetics of these plants to see if they belong to old crop lineages. Wetlands preserve a wealth of fascinating stories.
Restore wetlands to improve grazing lands
A recent review of research into how best to enhance carbon storage on grazed lands in the US identified wetland restoration as one of the most effective practices. Almost all of the wetland research and restoration projects that I have worked on were impacted by grazing, so the broad findings from this paper correspond well to my focused experience.
Making hay with scythes to restore wilderness meadows
Restoring Halstead Meadow, Sequoia NP
Thanks to the Northern California Botanists for inviting me to speak about Halstead Meadow, Sequoia and Kings Canyon National Parks at last month’s annual meeting in Chico. See the whole talk here:
Hot off the press: 20 years of research in Yellowstone
I started my professional ecological research with my Masters project in Yellowstone National Park more than two decades ago. During that project I helped establish the long-term research plots and data collection methods that led to this just-published summary of what happens when willows are protected from browsing and have extra water provided by simulated beaver dams.
As we hypothesized, the small streams in Yellowstone that used to support resident beaver for centuries, but lost them in the 1920s-1930s, have not seen a rapid recovery of willow just because wolves were reintroduced in the 1990s. Nor have the beavers returned in significant numbers. The impacted ecosystem, where streams eroded through the long-abandoned beaver dams and dried out conditions for willows, needs more than just reduced browsing pressure to recover.
Here’s a TikTok-er doing a good job summarizing our paper: https://www.tiktok.com/@natureexperienced/video/7331856319521017119
Click image below to go to free online paper:
Holocene stratigraphy and chronology of mountain meadows, Sierra Nevada, California
Spencer Hoffman Wood
CITATION
Wood, SH (1975) Holocene stratigraphy and chronology of mountain meadows, Sierra Nevada, California. PhD dissertation, California Institute of Technology, Pasadena, CA
FIGURE 2-1
WRITTEN SUMMARY
Valley-fill deposits, exposed by Twentieth-Century dissection of a number of meadows on the west slope of the southern Sierra Nevada, contain a stratigraphic record strongly affected by secular variations in watershed hydrology during the Holocene. Meadows are situated in low gradient reaches, adequately supported by seepage water, where fine textured materials accumulate under present hydrologic conditions· Meadows do not necessarily owe their origin to glacial modification of drainage. Many meadows have formed in both glaciated and unglaciated valleys by a water table rise in valley-fill deposits.
Ground water in any meadow drainage basin is annually recharged by snowmelt. Significant evapotranspiration by meadow plants causes diurnal fluctuations of growing-season water tables on the order of 0.2 to 0.5 ft and seasonal fluctuations of 2 to 4 ft. Growing-season water-table depths are characteristically different for the two major plant communities, being usually shallower than 2 feet for meadows, and deeper than 4 ft for conifer forests. This relationship and a ground-water model are used to interpret paleohydrologic variations recorded in valley-fill stratigraphy.
Stratigraphy, radiocarbon dating, and tephrachronology indicate the following sequence in upper tributary valleys of the montane belt. Pre-Holocene cobbly alluvium rests upon bedrock. A paleosol developed upon this alluvium between 10,200 and 8700 radiocarbon years B.P., records an early post-glacial climatic interval that established forests in the present upper montane belt. The overlying sequence of coarse loamy materials associated with in situ conifer stumps indicates one or more intervals of good soil drainage and dry valley-bottom conditions between 8700 and 1200 years B.P. At some sites there is an abrupt change from forest soils to overlying wet-meadow deposits dated 2500 years at some sites and 1200 years at others, suggesting many meadows originated coincidentally with neoglaciation in the Sierras. A water-table rise of a few feet, resulting from late melting snows, could cause the change from forest to meadow conditions. Meadow deposits are composed of organic-rich, sandy-loam, topsoil layers intercalcated with sheets of well-sorted sandy gravels deposited by flood flows with recurrence intervals greater than 50 years.
A plot of upstream catchment area and valley gradient for dissected and undissected meadows indicates the geomorphic domain of unstable meadows subject to gully erosion under present hydrologic conditions on the Sierra west slope.
Two pumiceous tephra layers, widespread in meadow topsoils of the southern Sierra, are radiocarbon dated and attributed to tephra-ringed eruptive centers at opposite ends of the Mono-Inyo Crater chain of eastern California. Tephra 1, characterized by sanidine microphenocrysts and Sr content of 215 ppm, erupted 720 years B.P. Distribution of this tephra is confined to a south trending lobe extending 120 miles over the Sierra from the upper San Joaquin drainage to the Little Kern drainage. Trace element analysis of tephra 1 best match those of the tephra-ringed obsidian flow just south of Deadman Creek in the Inyo Craters. Tephra 2, characterized by a lack of microphenocrysts and Sr contents less than 20 ppm erupted from one of the northern Mono Craters eruptive centers. These two tephras appear to represent the most recent explosive eruptions of magma from this 40-km long chain of Holocene volcanoes.
Animal life in the Yosemite; an account of the mammals, birds, reptiles, and amphibians in a cross-section of the Sierra Nevada.
Joseph Grinnell and Tracy Irwin Storer
CITATION
Grinnell, J, and TI Storer (1924) Animal life in the Yosemite: an account of the mammals, birds, reptiles, and amphibians in a cross-section of the Sierra Nevada. University of California Press.
FIGURE 39
WRITTEN SUMMARY
Of the thousands who each year visit the Yosemite Valley and its environs, a certain proportion are already interested in natural history; and anyone who leaves the region without gathering some definite knowledge of its natural history has failed to get adequate gain from his opportunities. The geology, topography, and botany of the Yosemite have been studied with some care; and there are instructive and stimulating manuals available dealing with these subjects. But heretofore only a few brief accounts have appeared in print concerning the bird life of the region, and practically nothing has been made available regarding its mammals, reptiles, and amphibians. It was in an effort to supply this deficiency that a survey of the vertebrate natural history of the Yosemite region was undertaken by the California Museum of Vertebrate Zoology. The present volume deals with the results of that survey.
The principal objects in view in undertaking the survey were: To find out what species of mammals, birds, reptiles, and amphibians exist, or have within modern times existed, in the circumscribed area selected for study; to learn as much as possible concerning the local distribution of each of these species, and to map out the general life areas within the region; to learn as much as time permitted of the food relations, the breeding habits, and the behavior, individually, of each of the species; and finally to put all this information on permanent record, in a form accessible to, and generally assimilable by, the public, both lay and scientific.
In attempting the achievement of this last aim the authors have brought together their materials with every precaution to insure accuracy of fact and correctness of inference. No sacrifice of precision has been made consciously with the end merely of affording ‘attractive reading.’ At the same time, technical terms, where the same ideas could be expressed in words familiar to every reader of fair education, have heen avoided. Ideally, we have tried to present our science, perfectly good science, in straightforward, readable form.