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Food Web of Sarracenia Purpurea in United States and Canada 1999-2011

How food webs are structured and how their structure and dynamics vary through time and space is a central focus of research in community ecology. We documented structural variation in the aquatic food web inhabiting pitcher-shaped leaves of the carnivorous pitcher plant Sarracenia purpurea across the geographic range of the plant (from Florida north to Labrador and west to British Columbia); examined temporal variation in this food web with detailed experiments in Massachusetts and Vermont; experimentally manipulated top-down and bottom-up processes in this food web in Massachusetts; and developed a dynamic simulation model of this food web that incorporates metacommunity dynamics.

Assessing Plant Phenological Character Displacement Across the Eastern United States Since 1895

Reproductive character displacement has long been hypothesized to be a key determinant of speciation and co-existence in flowering plants. A central tenet of this hypothesis is that reproductive traits of close relatives growing in sympatry diverge more than they do where close relatives do not grow together. However, this idea remains untested across taxa and at large spatial scales. Here, we use data collected from tens of thousands of herbarium specimens to examine evidence for character displacement in flowering time for 91 closely-related pairs of animal-pollinated angiosperm species in the eastern USA. We see no evidence for overall phenological divergence in sympatry across regions, clades, or life histories. Rather our results indicate widespread convergence of flowering times in sympatry for species pairs that generally tend to flower close in time. We also find that climate change could alter the nature of these convergent flowering events by shifting them further apart in a majority species pair comparisons. Specifically, congeneric species in New England and the Atlantic Coastal Plain are projected to flower 2–4 days further apart, on average, by the mid-21st century as warming temperatures drive species-specific phenological shifts within genera. This may have significant consequences for species interactions and gene flow, especially if current sympatric convergence in flowering times has resulted from facilitative interactions between species.

Tree Ring Data from Goose Egg State Forest NY 1681-2014

Is it possible to reconstruct aboveground carbon/biomass from tree rings? If so, how far back in time can researchers go when using tree-ring data in the reconstruction of past biomass? Answers to these questions will have a significant impact on our understanding of dynamics in the terrestrial carbon sink. Long tree-ring records of biomass can reveal intra-annual to annual to multidecadal variations that cannot be resolved by forest census data that is not conducted at annual time steps. Additionally, while these dynamics might be resolved using remote sensing, most remotely-sensed products are only two decades or less in length. By having long records of carbon biomass, we can then identify not only the dominant drivers of biomass, but how the importance of these drivers might change during different eras as environmental factors change (e.g., climate, air pollution, disturbance). To test these and other questions, we collected tree-ring records from three 30m radius plots set in Goose Egg State Forest in New York State. We chose this location because it has old oak dominated forests that can be compared to the long-term forests being studied for carbon dynamics at the Harvard Forest. We can convert these data to biomass using allometric equations and compare tree-ring inferred aboveground biomass to the census data going back in time to understand forest recovery and carbon dynamics in a heavily disturbance forest. Recruitment dates for some of the trees from these plots have been published in Pederson et al. (2017). Pederson, N., Young, A. B., Stan, A. B., Ariya, U., Martin-Benito, D. 2017. Low-Hanging DendroDynamic Fruits Regarding Disturbance in Temperate, Mesic Forests. In: Amoroso, M. M., Daniels, L. D., Baker, P. J., Camarero, J. J., Dendroecology: Tree-Ring Analyses Applied to Ecological Studies, Springer, Cham., Switzerland.

Tree Ring Data from North Round Pond in Pisgah State Forest NH 1754-2015

Is it possible to reconstruct aboveground carbon/biomass from tree rings? If so, how far back in time can researchers go when using tree-ring data in the reconstruction of past biomass? Answers to these questions will have a significant impact on our understanding of dynamics in the terrestrial carbon sink. Long tree-ring records of biomass can reveal intra-annual to annual to multidecadal variations that cannot be resolved by forest census data that is not conducted at annual time steps. Additionally, while these dynamics might be resolved using remote sensing, most remotely-sensed products are only two decades or less in length. By having long records of carbon biomass, we can then identify not only the dominant drivers of biomass, but how the importance of these drivers might change during different eras as environmental factors change (e.g., climate, air pollution, disturbance). To test these and other questions, we collected tree-ring records from four 30m radius plots set in the vicinity of North Round Pond in Pisgah State Forest, New Hampshire. Two plots are set in broadleaf-dominated forests while two are set in oak-mixed conifer dominated forests. We can convert these data to biomass using allometric equations and compare tree-ring inferred aboveground biomass to the census data going back in time. While a strong hurricane in September 1938 knocked down 80% of a stand ca 3.5 km SSE of these stands and the stands in the vicinity of the North Round Pond are set on N- and NW-facing slopes, and thus potentially shielded by the strong tropical winds, they, too, were disturbed by the hurricane of 1938. However, there are some very old trees and patches of trees in this landscape, while, at the same time, we suspect some logging impacted parts of some of these plots in the 1960s, like in North Round Pond Plot 1. The forest stands have since regrown and the plots we installed can be used to understand forest recovery and carbon dynamics in a heavily disturbance for

Tree Ring Data from the Harvard Tract in Pisgah State Forest NH 1675-2015

Is it possible to reconstruct aboveground carbon/biomass from tree rings? If so, how far back in time can researchers go when using tree-ring data in the reconstruction of past biomass? Answers to these questions will have a significant impact on our understanding of dynamics in the terrestrial carbon sink. Long tree-ring records of biomass can reveal intra-annual to annual to multidecadal variations that cannot be resolved by forest census data that is not conducted at annual time steps. Additionally, while these dynamics might be resolved using remote sensing, most remotely-sensed products are only two decades or less in length. By having long records of carbon biomass, we can then identify not only the dominant drivers of biomass, but how the importance of these drivers might change during different eras as environmental factors change (e.g., climate, air pollution, disturbance). To test these and other questions, we collected tree-ring records from two 30m radius plots set within Harvard’s Pisgah Tract in Pisgah State Forest, New Hampshire. We can convert these data to biomass using allometric equations and compare tree-ring inferred aboveground biomass to the census data going back in time. Famously, 80% of this tract was knocked down in September 1938 by a strong hurricane. The forest has sine regrown and the plots we installed can be used to understand forest recovery and carbon dynamics in a heavily disturbance forest. Given that this was a known/decently documented event, these data were used by Trotsiuk et al. (2018) to test various growth release methods as applied to tree-ring data. Trotsiuk, V., Pederson, N., Druckenbrod, D. L., Orwig, D. A., Bishop, D. A., Barker Plotkin, A., Fraver, S., Martin-Benito, D. 2018. Testing the efficacy of tree-ring methods for detecting past disturbances. Forest Ecology and Management 425: 59-67.

Tree Ring Data from Rooster Hill in Adirondack State Park NY 1828-2015

Is it possible to reconstruct aboveground carbon/biomass from tree rings? If so, how far back in time can researchers go when using tree-ring data in the reconstruction of past biomass? Answers to these questions will have a significant impact on our understanding of dynamics in the terrestrial carbon sink. Long tree-ring records of biomass can reveal intra-annual to annual to multidecadal variations that cannot be resolved by forest census data that is not conducted at annual time steps. Additionally, while these dynamics might be resolved using remote sensing, most remotely-sensed products are only two decades or less in length. By having long records of carbon biomass, we can then identify not only the dominant drivers of biomass, but how the importance of these drivers might change during different eras as environmental factors change (e.g., climate, air pollution, disturbance). To test these and other questions, we collected tree-ring records from two 30m radius plots set Rooster Hill in New York State. We chose this location because it has oak dominated mixed forests that can be compared to the long-term forests being studied for carbon dynamics at the Harvard Forest. We can convert these data to biomass using allometric equations and compare tree-ring inferred aboveground biomass to the census data going back in time to understand forest recovery and carbon dynamics in a heavily disturbance forest.

openCC (other)May 2024View details →

Annual precipitation and photo-derived vegetation and litter cover (2013-2021) used for analysis in the manuscript “Growing grasses in the desert: Multi-scale Interactions and State Change Reversal in Drylands”

This dataset contains water year precipitation collected from meteorological stations, litter and vegetation cover values derived from overhead photos, and litter and soil accumulation in lateral photos in a long-term experiment (2013-2021) of cross-scale interactions (CSIs) at the Jornada Basin LTER site in southern New Mexico, U.S.A. Manipulations were initiated in 2013 at 15 experimental blocks, each with 4 treatment plots: plant-scale herbicide of mesquite shrubs, patch-scale connectivity modifiers (ConMods), herbicide + ConMods, control without manipulations. Litter, soil, and vegetation cover were estimated using repeat overhead photographs of microplots within treatment and control plots. Litter and soil accumulation were estimated from lateral photos of ConMods. This dataset utilized QuickBird imagery from 2011 to assess ground cover classes within the Jornada Basin, focusing on bare ground, herbaceous, and shrub cover. Daily precipitation data collected from 13 meteorological stations were used to calculate water year (1 October-30 September) precipitation from 2013 through 2021. This dataset provides supporting data for the manuscript "Growing grasses in the desert: Multi-scale Interactions and State Change Reversal in Drylands" by Peters et al.

openCC0Jun 2025View details →

Harmonized Palmer Drought Severity Indices throughout the Contiguous United States for HydroBASINS basins

In times of a changing hydroclimate and growing human population, there is a need to assess how various climatic and demand conditions influence water availability on the landscape. Tendency for drought conditions is a prime example of a key hydroclimatic metric that is useful for understanding water retention in the surrounding landscape. However, merging drought climatological data with co-located aquatic data is challenging. To facilitate national-scale analyses of basin-level drought conditions (i.e., Palmer Drought Severity Index; PDSI) with co-located water quality data, we present aggregated PDSI data for the contiguous United States. Data are aggregated using the HydroBASINS basin shapefiles. HYBAS_ID is retained to enable merging with HydroBASINS parent datasets.

openCC0Jun 2025View details →

Harmonized Soil Organic Carbon and Phosphorus Data for the Contiguous United States

Soil organic carbon (SOC) and soil phosphorus can strongly influence adjacent water quality by introducing nutrients into aquatic ecosystems and also altering the light environment of those ecosystems. However, national-scale data are uncommon, and even when available, they are usually not aggregated in a manner that is expeditiously merged with basin-level data. To facilitate national-scale analyses of soil data with co-located water quality data, we present aggregated SOC and soil phosphorus data for the Contiguous United States. Data are aggregated using the HydroBASINS basin shapefiles. HYBAS_ID is retained to enable merging with HydroBASINS parent datasets.

openCC0Nov 2025View details →

Juvenile Salmonid Emigration Monitoring in the Stanislaus River at Caswell Memorial State Park, California, 2017-2025

Overview Operation of rotary screw traps on the lower Stanislaus River at Caswell Memorial State Park is part of the U.S Fish and Wildlife Service’s Anadromous Fish Restoration Program and Comprehensive Assessment and Monitoring Program under the National Marine Fisheries Service Reasonable and Prudent Alternatives actions and Central Valley Project Improvement Act. The primary objectives of the study are to collect data that can be used to estimate the passage of juvenile fall-run Chinook Salmon Oncorhynchus tshawytscha and to quantify the raw catch of steelhead Oncorhynchus mykiss. Secondary objectives of the trapping operations focus on collecting biological data on juvenile salmonids and gathering environmental data that will be used to develop models that correlate environmental parameters with salmonid size, temporal presence, abundance, and production. The data package contains seven datasets including: raw catch, trap operation, environmental, and trap efficiency data. Raw Catch – Chinook Dataset This dataset covers ALL Chinook Salmon captured by the rotary screw traps. This spreadsheet includes biological data on: 1) unmarked fall- and spring-run Chinook Salmon 2) recaptured marked fall-run (BBY OR "Pigment / Dye", Photonic Dye, Fin Clip, and VIE OR "Elastomer") Chinook Salmon utilized in trap efficiency trials. Raw Catch – Steelhead Dataset This dataset covers ALL steelhead captured by the rotary screw traps. All steelhead captured are unmarked and presumed to be natural origin steelhead. Raw Catch – ByCatch Dataset This dataset provides biological data on ALL catch (EXCLUDING Chinook Salmon or steelhead) captured by the rotary screw traps. All catch in this table is of natural origin. Trap Operations Dataset This dataset provides trap operation data for each trap visit. Specifically, it includes data on the visit type, trap functioning status, start and end sampling dates and times, total revolutions and instantaneous revolution speeds, livewell intake st

Proteolytic Enzyme Activity in Temperate Forest Soils at Harvard Forest and Pisgah State Forest 2007-2010

The objective of this research is to investigate the processes that limit or promote the activity and production of proteolytic enzymes in temperate forest soils. To meet this objective, we performed a series of integrated observations and experiments to investigate a conceptual model of proteolytic enzyme activity whereby activity is a function of the interaction between four parameters: soil temperature and moisture, substrate concentration, and the enzyme pool size. We used four dominant temperate forest tree species that differ in SOM chemistry and the enzymatic capabilities of their fungal symbionts as a model system. These four species differed in mycorrhizal association, with white ash (Fraxinus americana) and sugar maple (Acer saccharum) supporting arbuscular mycorrhizal (AM) fungi and eastern hemlock (Tsuga canadensis) and American beech (Fagus grandifolia) supporting ectomycorrhizal (ECM) fungi. Further, the ECM associated species have leaf litter and SOM that is characterized by higher ratios of C:N than the AM associated. Soil samples were collected two sites, one located at the Prospect Hill Tract of the Harvard Forest and the other at the Pisgah State Forest. The sites have similar land use history and stand age. Soils at both sites are inceptisols classified as Typic Dystrochrepts derived from glacial till overlying granite-schist-gneiss bedrock. Experimental plots dominated by one of four target tree species were established at each site. Stands of sugar maple (Acer saccharum) and American beech (Fagus grandifolia) were located in Pisgah. Stands of Eastern hemlock (Tsuga canadensis) and white ash (Fraxinus americana) were located in Harvard Forest. At a later date, plots were also established in a red oak (Quercus rubra) stand on Prospect Hill in the MES tower footprint. At each site we located six replicate, 8 m radius, monodominant plots that were based on the following criteria: (1) more than 80% of the standing basal area was composed of the targ

Extracellular Enzyme Activity in Rhizosphere Soil at Harvard Forest and Pisgah State Forest 2010

The exudation of carbon (C) by tree roots stimulates microbial activity and the production of extracellular enzymes in the rhizosphere. Here, we investigated whether the strength of rhizosphere processes differed between temperate forest trees that vary in soil organic matter (SOM) chemistry and associate with either ectomycorrhizal (ECM) or arbuscular mycorrhizal (AM) fungi. We measured rates of microbial and extracellular enzyme activity, and nitrogen (N) availability in samples of rhizosphere and bulk soil influenced by four temperate forest tree species (i.e., to estimate a rhizosphere effect). The magnitude of the rhizosphere effects could not be easily characterized by mycorrhizal associations or SOM chemistry. Ash had the lowest rhizosphere effects and beech had the highest rhizosphere effects, representing one AM and one ECM species, respectively. Hemlock and sugar maple had equivalent rhizosphere effects on enzyme activity. However, the form of N produced in the rhizosphere varied with mycorrhizal association. Enhanced enzyme activity primarily increased amino acid availability in ECM rhizospheres and increased inorganic N availability in AM rhizospheres. These results show that the exudation of C by roots can enhance extracellular enzyme activity and soil-N cycling. This work suggests that global changes that alter belowground C allocation have the potential to impact the form and amount of N to support primary production in ECM and AM stands.

Life History of a Climax Forest in Pisgah State Forest in Winchester NH 1929-1930

Old-growth forest is uncommon across the northeastern United States, as most areas have been historically cleared for agriculture or harvested for timber. This study provides rare direct insight into the overstory and midstory dynamics across a semi-contiguous old-growth landscape in New England. Pisgah State Park in southwestern New Hampshire comprises 5300 ha of Hardwoods-Hemlock-White Pine forest, all but 300 ha of which was cutover by the 1880s. To protect a high-quality, old-growth stand from harvest, Harvard Forest purchased a 10 ha tract (the Harvard Tract) in 1927. In 1929 and 1930, Branch, Daley, and Lotti located and sampled all of the known remaining old-growth stands in the Pisgah area. This included 74 0.04 ha old-growth stands, 14 of which were located the Harvard Tract. They also surveyed 27 0.04 ha stands that had been cut just prior to the study (stump plots), where stumps as well as the remaining overstory trees were recorded. Note that only 61 old-growth plots and 23 stump plots have valid measurements. Species, diameter class, and position (overstory or midstory) were recorded for each tree; cover type, elevation, and location was described for each plot. Dead and downed trees were also recorded.

Assessing Plant Phenological Patterns in the Eastern United States Over the Last 120 Years

Phenology is a key biological trait of an organism’s success and is one of the best indicators of its response to recent climate change. Plants are among the most well-studied organisms in this regard, but observational data bearing on this topic are largely restricted to woody species of the northern hemisphere, mostly from ca. the last three decades. Recent research has demonstrated that mobilized online herbarium specimens provide important, albeit mostly neglected, information on plant phenology. Here, we use the web tool CrowdCurio to crowdsource phenological data from more than 10,000 herbarium specimens representing 30 flowering plant species broadly distributed across the eastern United States. Our results, spanning 120 years and generated from over 2,000 crowdsourcers, clarify numerous aspects of plant phenology. First, they reveal that plant reproductive phenology is significantly advancing in response to warming, which is consistent with previous studies. Second, among those species with broad latitudinal ranges, populations from more southern latitudes are significantly more phenologically sensitive to temperature than those from northern populations. Last, contrary to some recent findings, plants in warmer, less variable climates may be much more dynamic, on average, in their phenological sensitivity. Our results are robust to a variety of confounding factors and span large phylogenetic distances and myriad life histories. These may represent more global trends in the latitudinal gradient of phenological response with myriad potential ecological and evolutionary consequences, and leads us to hypothesize that phenological sensitivity across species' ranges is driven by adaptation to local climates.

Legacies of Historical Clearcutting, Wind and Salvage Logging in Pisgah State Forest 2016

Disturbance events affect forest composition and structure across a range of spatial and temporal scales, and subsequent forest development may differ after natural, anthropogenic, or compound disturbances. Following large, natural disturbances, salvage logging is a common and often controversial management practice in many regions of the globe. Yet, while the short-term impacts of salvage logging have been studied in many systems, the long-term effects remain unclear. We capitalized on over eighty years of data following an old-growth Tsuga canadensis-Pinus strobus forest in southwestern New Hampshire, USA after the 1938 hurricane, which severely damaged forests across much of New England. To our knowledge, this study provides the longest evaluation of salvage logging impacts, and it highlights developmental trajectories for Tsuga canadensis-Pinus strobus forests under a variety of disturbance histories. Specifically, we examined development from an old-growth condition in 1930 through 2016 across three different disturbance histories: (1) clearcut logging prior to the 1938 hurricane with some subsequent damage by the hurricane (“logged”), (2) severe damage from the 1938 hurricane (“hurricane”), and (3) severe damage from the hurricane followed by salvage logging (“salvaged”). At each site, 2-4 0.05 ha plots were established, and DBH, species, and distance and direction from plot center were recorded for each tree over 10 cm DBH. Stumps and snags were also measured. From the site center, coarse woody material was measured along three 34-m transects using the line-intersect method. Finally, a 1-ha plot was established around the site center, within which all pit-and-mound structures and stumps were recorded as well as boles associated with these structures.

Historical and Ecological GIS Data from Manuel F. Correllus State Forest on Martha’s Vineyard 1830-1994

Sand-plain ecosystems are a priority for conservation because they are uncommon, support numerous rare or uncommon plant and animal species, serve as groundwater recharge areas, and are threatened by land development. The 5,200-acre Manuel F. Correllus State Forest, in the central part of Martha’s Vineyard, is part of one of the larger sand-plain ecosystems in New England. This GIS data package was created as part of a study on the history and ecology of Martha’s Vineyard and the state forest as part of an effort to understand sandplain landscapes and make management recommendations for their maintenance.

Lake Sediment Pollen from Spruce Pond in Harriman State Park NY from 13778 BP to Present

Aim We analyzed a dataset composed of multiple palaeoclimate and lake-sediment pollen records from New England to explore how postglacial changes in the composition and spatial patterns of vegetation were controlled by regional-scale climate change, a subregional environmental gradient, and landscape-scale variations in soil characteristics. Location The 120,000-km2 study area includes parts of Vermont and New Hampshire in the north, where sites are 150-200 km from the Atlantic Ocean, and spans the coastline from southeastern New York to Cape Cod and the adjacent islands, including Block Island, the Elizabeth Islands, Nantucket, and Martha’s Vineyard. Results Boreal forest featuring Picea and Pinus banksiana was present across the region when conditions were cool and dry 14,000-12,000 calibrated 14C yrs before present (ybp). Pinus strobus became regionally dominant as temperatures increased between 12,000 and 10,000 ybp. The composition of forests in inland and coastal areas diverged in response to further warming after 10,000 ybp, when Quercus and Pinus rigida expanded across southern New England, while conditions remained cool enough in inland areas to maintain Pinus strobus. Increasing precipitation allowed Tsuga canadensis, Fagus grandifolia, and Betula to replace Pinus strobus in inland areas during 9000-8000 ybp, and also led to the expansion of Carya across the coastal part of the region beginning at 7000-6000 ybp. Abrupt cooling at 5500-5000 ybp caused sharp declines in Tsuga in inland areas and Quercus at some coastal sites, and the populations of those taxa remained low until they recovered around 3000 ybp in response to rising precipitation. Throughout most of the Holocene, sites underlain by sandy glacial deposits were occupied by Pinus rigida and Quercus. Main conclusions Postglacial changes in the composition and spatial pattern of New England forests were controlled by long-term trends and abrupt shifts in temperature and precipitation, as well as by

openCC0Jan 2025View details →

Permanent Plots at Pisgah State Forest in Winchester NH since 1984

There are relatively few studies that have examined forest structure and composition both before and after a catastrophic wind disturbance has altered the forest. On a twenty acre parcel of old-growth forest located in the Pisgah State Forest in southwest New Hampshire, the collection of a long term data set from 1907-1995 has made it possible to consider how the hurricane of 1938 altered forest structure, species composition, and subsequent forest development in the stand. Various types of information were gathered throughout the century that allowed the quantification of forest structure and composition: species identification, diameter measurements, tree status (living or dead), tree cores, and individual tree growth and mortality have recently been tracked. The old-growth forest before 1938 was dominated by a Pinus-Tsuga-Hardwood mix. The hurricane left the forest devastated and incredibly altered. The total basal area of the forest was drastically reduced from approximately 70m2/ha to about 5m2/ha after the disturbance. White pine was effectively lost from the stand while many large Tsuga were also blown down. A large increase in density was subsequently recorded as many post-disturbance species took advantage of the resources that had been made available, especially light. Although there was a high level of destruction, a good amount of Tsuga and Fagus that had previously existed in the understory was released from suppression and grew to fill in parts of the overstory. Both the forest structure and the species composition changed from a relatively homogeneous state before the hurricane to an extremely heterogeneous one after the hurricane. The overall development of the stand followed the typical path of a recently disturbed area: after the initial increase in density in the few years after the storm, basal area has been steadily increasing while density has steadily decreased. It has also been possible to observe differences in the ability of individual spec

Using Phenology to Forecast Species Distributions across the Eastern United States in the 2070s

Studies that use species distribution models (SDMs) to document the relationship between species’ geographic range and environmental conditions rarely consider functional traits, such as phenology, that strongly affect species’ demography and fitness. Using more than 120,000 herbarium specimens representing 360 plant species across the eastern United States, we created a novel “phenology-informed” SDM that integrates dynamic phenological responses to changing climates. Compared to standard SDMs based only on abiotic variables, our phenology-informed SDMs forecast significantly lower species habitat loss, and less species turnover within communities under climate change. These results suggest that phenotypic plasticity and/or local adaptation in phenology may help many species adjust their ecological niches and persist in their habitats during periods of rapid environmental change. By modeling historical data that link phenology, climate and species distributions, our findings reveal how species’ reproductive phenology mediates their geographic distributions along environmental gradients and affect regional biodiversity patterns under future climate changes. More importantly, our newly developed model also circumvents the need for mechanistic models that explicitly link traits to occurrences for each species, and could thus facilitate the deployment of trait-based SDMs across unprecedented spatial and taxonomic scales.