Find research datasets worth reusing

openCC0Nov 2024View details →

Point-count bird censusing: long-term monitoring of bird abundance and diversity in central Arizona-Phoenix, ongoing since 2000

### project overview Over the past half-century, the greater Phoenix metropolitan area (GPMA) has been one of the fastest growing regions in the US, experiencing rapid urban expansion in addition to urban intensification. This backdrop provides an ideal setting to monitor biodiversity changes in response to urbanization, and the CAP LTER has been using a standardized point-count protocol to monitor the bird community in the GPMA and surrounding Sonoran desert region since 2000. The bird survey locations in this CAP LTER core monitoring program include six general site groupings: 1. ESCA. Forty bird survey locations were selected from a subset of the CAP LTER's Ecological Survey of Central Arizona (ESCA; formerly named Survey200) long-term monitoring sites. ESCA sites were located using a tessellation-stratified dual-density sampling design, and, as such, span a diversity of habitats including urban, suburban, rural, commercial areas, parks, agricultural fields, and native Sonoran desert. Earlier versions of this data package included data from the ESCA project that was intended to complement the bird data. However, while positioned in close proximity, the bird survey locations do not necessarily overlap with the 30m x 30m plot that constitutes an ESCA sampling location, and leveraging data from these two monitoring programs should be addressed carefully. ESCA data have corresponding survey location names, and those data are available through the CAP LTER and LTER network data portals. At the conclusion of the 2016 spring survey, fifteen of the ESCA-correlated sites were discontinued as the core monitoring program refocused its efforts on desert parks and PASS neighborhoods. Among the deleted locations were all agricultural and commercial sites, as well as sites where access had become restrictive. 2. North Desert Village (NDV). Additional bird survey locations were positioned in treatment areas of the North Desert Village (NDV). This was a site of intense study on t

Moose Foraging in Temperate Forests of Central Massachusetts 2005

The "re-wilding" of ecosystems with extirpated large mammals has become a focus of recent scientific and conservation initiatives; however, it is unclear how proposed re-introductions will influence systems that are often vastly different from those that occurred before these animals were extirpated. Moose, the northeast’s largest Holocene browser, have recently expanded across southern New England’s temperate forest landscape after an absence of 200 years, realizing a natural re-wilding experiment. Moose have been well-studied throughout the boreal forest biome; however, because they are rare today in temperate forests, almost nothing is known of their ecology, behavior, or potential impacts to these ecosystems. This study investigated patterns of winter moose browse in order to: (1) gain insight into the likely influences of this herbivore on the vegetation patterns of the region; and (2) to identify the most important habitat features influencing moose winter foraging activity at a landscape and site scale. Two large forested watersheds in Central Massachusetts were sampled for moose browse, habitat features, and disturbances including forest harvesting and human activity. Chi-square and t-tests were used to identify browse species preferences of moose, and step-wise multiple regression was used to identify habitat variables that are strong predictors of browse intensity. Hardwoods and hemlock were favored over white pine, and browse intensity was significantly and positively related to forest harvesting, elevation, swamps, and distance to human settlement. The results from this study suggest that in the winter months, moose populations are concentrating in remote, elevated areas that are broken by swamps and have intensive forest harvests. In areas that support high moose densities, selective browsing, particularly in regenerating harvests, could promote less favored species like white pine at the expense of hardwoods and hemlock. The strong association between

Impacts of Hemlock Harvesting in Central Massachusetts 2003-2009

The recent unimpeded infestation of the hemlock woolly adelgid (HWA; Adelges tsugae) across the northeastern U.S. is driving large-scale hemlock decline and mortality. HWA has already infested over 40% of the towns in Massachusetts and, as a result, many landowners are considering pre-emptively harvesting their eastern hemlock (Tsuga canadensis) stands. To examine the local impacts of this cutting activity, we examined stand and ecosystem dynamics in 10 hemlock-dominated sites on public and private lands where hemlocks were harvested between 1 to12 years ago with nearby uncut forests. Forty-two to ninety-seven percent of hemlock stems and basal area were removed from the harvested sites. Sapling densities of 10,500 to 24,000 stems ha-1 dominated the vegetation at older cuts and consisted primarily of black birch (Betula lenta), red maple (Acer rubrum), and white pine (Pinus strobus). Seedling densities averaged 5 m-2 across sites, peaked at 20 m-2 at 6 to 9 year old sites, and consisted of hemlock, white pine, black birch, and red maple. Additional understory species that were common in cuts sites included various raspberry (Rubus) species, often averaging 30% cover, hay-scented fern (Dennstaedtia punctilobula), and various sedge (Carex) species. Harvesting resulted in soils that were 3 to 5 (deg C) warmer and tended to be drier in recent vs. older cuts. Net nitrogen mineralization rates in organic soils averaged just over 10 kg N ha-1yr-1 in recent cuts and approx. 5 kg N ha-1yr-1 in older cuts. Mineral soil net mineralization rates were lower among all cuts, ranging from 2.1 to 3.5 kg N ha-1yr-1. Nitrification rates were low in both soil horizons at all harvest ages. Recent cuts had much higher nitrogen capture (NH4- + NO3+) on resin bags averaging around 1200 μg N g resin-1 vs. 300 to 600 μg N g resin-1 captured in older cuts. Nitrification rates and nitrate capture on resin bags were lower in Massachusetts sites than those reported on sites with a long history o

Eastern Redback Salamander Abundance in North Central Massachusetts 2005

Throughout the twentieth century several dominant tree species suffered severe decline in the eastern United States due to non-native pests and pathogens, yet little is known of the effects these losses have on ecosystem processes or associated wildlife populations (Orwig 2002). Eastern hemlock (Tsuga canadensis), an important late-successional tree species, is currently threatened throughout its range by the hemlock woolly adelgid (Adelges tsugae; HWA), an invasive insect pest native to Japan (Orwig and Foster 1998). The unique structure and microenvironment of hemlock-dominated forests create critical landscape level heterogeneity, providing habitat for numerous bird and mammal species several of which are strongly associated with hemlock stands in the Northeast (Yamasaki et al. 2000). The effects of hemlock loss on associated wildlife is largely unknown, but is of particular concern for terrestrial salamanders as they are sensitive to microclimatic conditions that are likely to change as hemlocks decline. In this study, populations of eastern red-backed salamanders (Plethodon cinereus), significant contributors to the overall vertebrate biomass in northeastern forests (Burton and Likens 1975a), are compared in hemlock-dominated and mixed deciduous forest. The objectives of this study was to 1) to determine whether the relative abundance, body condition, and size class structure of P. cinereus populations differ in hemlock-dominated forests versus mixed deciduous forests in north-central Massachusetts. A difference in age-class structure in the two forest types may suggest a difference in survivorship, while differences in body condition are driven by differences in the energy expenditure required to obtain food resources and can lead to differences in reproductive success 2) to evaluate how structure and microenvironment differ and determine which variables best predict the variation in relative abundance and body condition of P. cinereus in the two forest types.

Ungulate-Forest Interactions in Partially Harvested Oak-Pine Stands in Central Massachusetts 2009

Ungulates are attracted to forest openings created by natural disturbance and timber harvesting due to the abundance of high quality browse in these openings. Despite the increased activity and browsing of ungulates in forest openings, the importance of browsing relative to abiotic factors such as light on forest regeneration is often unclear. In southern New England, medium-intensity harvesting is the predominant forest disturbance attracting white-tailed deer and moose. Oaks are the foundation hardwood taxon and predominant timber tree in the region and are in decline. Hence, the effects of ungulate browsing on oak forests are of great interest to ecologists, conservationists and forest and wildlife managers. We sampled tree regeneration and ungulate foraging activity across a range of canopy disturbances (35-90% basal area removed) in 34 stands of the Quabbin and Ware River Watershed Forests. Browsing was very high across the plots with about 80% of red maple and oak stems browsed. Taller stems were generally browsed more frequently than shorter stems. Oak regeneration in the smaller size classes was generally lower in stands with higher percent cover of hay-scented fern. The proportion of browsed red maples and oaks generally increased with increasing density of these taxa. Despite intensive herbivory, oaks appear to be regenerating well with increased light in these partially harvested stands.

openCC0Mar 2024View details →

Leaf and Soil Nitrogen Following Lymantria dispar Defoliation in Central Massachusetts 2018-2019

In this study we investigated relationships between ecosystem nitrogen (N) cycling and tree defoliation during a recent 2015-2018 irruption of invasive Lymantria dispar caterpillars, which can cause tree stress and sometimes mortality following multiple years of defoliation. Nitrogen is a critical nutrient that limits the growth of caterpillars and plants in temperate forests. We assessed the associations between N concentrations, soil solution inorganic N availability, and defoliation intensity by L. dispar at the scale of individual trees in the Amherst, MA area and forest plots in the Quabbin Reservoir area.

openCC0Jan 2025View details →

Lymantria dispar Defoliation and Mortality Survey at the Quabbin Watershed in Central Massachusetts 2017-2022

For most of the 20th century, the invasive Lymantria dispar was the most serious insect threat to forests and shade trees in the northeastern United States, but outbreaks have been sporadic and light since 1989, after the successful establishment of a fungal pathogen, Entomophaga maimaiga. However, in 2016 a surprising new outbreak of Lymantria dispar began in southern New England, resulting in dramatic oak (Quercus spp.) mortality across thousands of forested hectares by 2018. In 2017, during the height of the outbreak, a rapid assessment of defoliation across 486 plots in six clusters (aka ‘hotspots’) across the Quabbin Watershed Forest in central Massachusetts was conducted. These sample points can be related to satellite-based defoliation estimates, and the tree and site data analyzed for predictors of defoliation severity. In 2022, we returned to 204 of these plots to assess oak mortality, understory vegetation, and oak regeneration.

Nonstructural Carbohydrates in Defoliated Oaks in Central Massachusetts 2019-2020

Carbon starvation posits that defoliation- and drought-induced mortality results from drawing down stored nonstructural carbohydrates (NSCs), but evidence is mixed and mortality is often observed prior to full drawdown of NSCs. We tested the relationship between defoliation severity, NSC drawdown, and tree mortality by measuring NSCs in mature oak trees defoliated by Lymantria dispar across a natural experimental gradient of defoliation severity. We collected stem and root samples from oaks (Quercus rubra and Q. alba) in interior forests (n=34) and forest edges (n=47) in central Massachusetts, USA. Total NSC (TNC; sugar + starch) stores were analyzed with respect to tree size, species, and defoliation severity, which ranged between 5 and 100%. Forest edge trees had higher TNC stores that were less sensitive to defoliation than interior forest trees. However, TNC stores declined significantly in both groups with increasingly severe defoliation. Furthermore, we observed a mortality threshold of 1.5% dry weight TNC. Our study draws a direct link between insect defoliation and TNC reserves and defines a TNC threshold below which mortality is highly likely. These findings advance understanding and improve model parametrization of tree response to insect outbreaks, an increasing threat with globalization and climate change.

Conservation Study in North Quabbin Region of Central Massachusetts 1900-1993

This study investigated the history of land protection in north central Massachusetts. For details on methods and results, please see the published paper (Golodetz, A.D. and D.R. Foster. 1997. History and importance of land use and protection in the North Quabbin region of Massachusetts (USA). Conservation Biology 11:227-235). The Abstract from the paper is reproduced below: "Evaluating the consequences and future of land protection requires broad temporal and spatial perspectives of ecological and cultural factors. We assessed the development of a system of protected areas comprising 37% of central Massachusetts in terms of changing rates and means of land protection. We compared protected areas to the surrounding matrix in terms of physical, biological, and historical features and used these results to raise issues concerning future planning. The rate, purpose, and means of land protection in the North Quabbin Region (168,312 ha) have been dynamic as a result of changes in cultural values and transformation of the landscape from predominantly agriculture to forest. Protected lands are managed by 25 federal and state agencies, private groups, and municipal departments and commissions and are physically and biologically typical of the regional landscape which results from (1) participation of diverse organizations with varied agendas; (2) predominance of large government acquisitions driven by landscape-scale criteria; and (3) absence of coordination among groups. The large area, relative homogeneity and largely undeveloped status of the North Quabbin Region suggest conservation goals distinct from those in the fragmented and extensively developed neighboring areas of the Connecticut River Valley and Cape Cod and Islands Region. Large tracts of forests, wetlands, and lakes in the North Quabbin Region provide (1) habitat for species requiring extensive, intact areas; (2) the opportunity to maintain broad-scale ecological processes; (3) connections to the regional con

openCC0Mar 2024View details →

Oak Forest Response to Lymantria dispar Defoliation in Central Massachusetts since 2019

Invasive forest insects are a major global change driver, and the Northeastern U.S. is an invasion hotspot. Lymantria dispar is one of the region’s most destructive defoliators. After thirty years of quiescence, a surprisingly severe outbreak began in 2015 in southern New England, and by 2018 had caused dramatic oak mortality across thousands of forested acres. Lymantria dispar is considered a generalist, but in New England, oaks (Quercus sp.) are its preferred host trees. Oaks are key overstory trees in eastern North America. In New England, they have been a dominant component of the forest for thousands of years, and play a leading role in providing habitat, timber, and carbon sequestration. However, oak prominence is declining throughout New England. The reasons for oak’s decreasing abundance are the subject of lively debate but the role of L. dispar is likely underappreciated. Therefore, we need to understand the causes and consequences of oak dieback and mortality to this disturbance event, so that we can better predict responses to future outbreaks. To address this need, we established a set of permanent plots in central Massachusetts, chosen to capture a range of defoliation severity.

Timber Harvesting Study in North Quabbin Region of Central Massachusetts 1984-2001

Although the northeastern U.S. includes extensive areas of aggrading forest, uncertainty regarding the intensity and pattern of forest harvesting hampers an understanding of important ecological processes and characteristics such as carbon and nitrogen storage, habitat quality, and forest dynamics, and impedes regional conservation and management planning. Due to the complex ownership pattern dominated by thousands of non-industrial private forest (NIPF) owners and the difficulty of detecting selective logging using remote sensing, details of the harvesting regime remain largely unknown to the scientific and policy communities. To examine the value of statewide regulatory data for Massachusetts as a unique source of this critical information, we analyzed 17 years of timber harvest data gathered for regulatory purposes for a 168,000-ha forested landscape in Massachusetts that is the focus of concerted conservation planning and intensive study of landscape and ecosystem pattern and process. The North Quabbin Region is heavily wooded with a complicated ownership pattern dominated by over 2,500 NIPF owners, three state agencies, and diverse conservation and municipal holdings. The extent and intensity of harvesting were surprising, with an annual disturbance rate of 1.5% and a mean intensity of 44.7 m3 ha-1 (approximately one-fourth of average stand volume). The predominant form of harvesting was selective removal of commercially valuable tree sizes, grades and species (e.g., Quercus rubra and Pinus strobus). The spatial pattern of logging was random with regards to major physical, biological, or cultural factors. However, logging was strongly related to landowner class. NIPF owners control 60% of the forest area and were responsible for 64.1% of harvest area, but the highest logging intensity (volume per area harvested; 69.3 m3 ha-1) among major landowners was conducted by the state agency responsible for managing southern New England's largest conservation property, t

Long-Term Dynamics of Oak and Chestnut in Central Massachusetts from 3500 BP to Present

Despite decades of study we have limited insights into the nature of the pre-European landscape of the northeastern USA and the forces and changes that shaped modern forest patterns. Information on such long-term forest dynamics would provide critical insights into the relationships among environmental change, land-use history and biotic responses and is greatly needed for conservation planning. To address these issues we used modern, historical, and paleoecological approaches to reconstruct the 3500-year history of a New England upland region dominated by oak and (formerly) chestnut forests and to interpret the interactions among climate change, natural and human disturbance, and site factors in controlling vegetation patterns and dynamics at different spatial scales. The results indicate that stand, landscape and regional forest dynamics were most strongly driven by climate, notably an apparent cooling and increase in moisture availability c. 1500 yr BP, and European land-use activities commencing 260 yr BP. However, the abundance of oak and chestnut (fire-tolerant, sprouting species) and the distribution of hemlock (fire-intolerant) at a stand to landscape scale were also influenced by fire, which, in turn, varied with climate and human activity. Despite, or perhaps as a consequence of ongoing disturbance by fire and presumably windstorms in this hurricane-prone region, the pre-European period was marked by two 1000+ year periods of remarkably stable forest composition, separated by an abrupt compositional shift. In contrast, over the past 260 years the vegetation has changed rather continuously in response to human activity, producing stand, landscape and regional patterns that are novel as well as recent in origin. Chestnut was a major component of some pre-European landscapes in New England, in part because of occasional fire, and that cultural and physical factors have interacted over millennia to control vegetation patterns and dynamics. Our analyses also su

Headwater Habitat Streams in Central Massachusetts 2002-2005

Headwater streams, particularly those that flow only during part of the year, are understudied and underprotected in Massachusetts. Research being conducted elsewhere suggests that these "Headwater Habitat Streams" are important both for aquatic biodiversity and for ecological function of lower stream reaches. We are carrying out baseline research, involving research scientists and volunteers, on hydrology and habitat characteristics in headwater streams in northern Worcester County, MA. We hypothesized that headwater streams exhibit a longitudinal gradient of hydrology, from (1) ephemeral channels that flow only in response to storms, through (2) intermittent sections that flow seasonally until the groundwater table falls below the channel and are dry the rest of the year, to (3) interstitial reaches that flow seasonally and retain pools connected by subsurface flow during the summer, to (4) the perennial stream. Results to date show a high degree of longitudinal heterogeneity in the study streams, with interspersion of perennially flowing reaches among low-gradient sections of vegetated wetland, high-gradient boulder piles, and braided channels. Perennial flow is found high up in some watersheds. We expect our methods and results will have implications throughout the Commonwealth for local conservation commissions and other municipal officials responsible for land-use planning and regulation, state agencies responsible for land management and the protection of wildlife, regulators reviewing projects affecting streams, watershed managers, teachers and their students, private land trusts, conservation advocates, and citizen-naturalists.

Stream Periphyton Response to Hemlock Mortality in Central Massachusetts 2006

The Hemlock Wooly Adelgid (HWA) invasion is expected to cause widespread mortality of eastern hemlock [Tsuga canadensis (L.) Carriere] throughout much of New England. Light levels in streams with hemlock riparian zones are anticipated to increase as hemlock are replaced by deciduous trees. We sought to: 1) quantify differences in light reaching streams with hemlock and deciduous riparian zones, 2) determine if increases in light result in higher periphyton biomass, and 3) explore the role of macroinvertebrate grazing on periphyton biomass as light increases in an attempt to help predict stream ecosystem responses to hemlock mortality. Light measurements were taken along 100-800m stream reaches with riparian zones of healthy hemlock and deciduous trees in MA and CT in order to document an integrated light profile for each stream. In addition, a 2 x 2 factorial experimental design with five replicates was executed on a deciduous reach of Egypt Brook in central MA, in which light (high light vs. low light) and grazing (high grazing vs. low grazing) were manipulated. Light measurements were significantly higher for streams with deciduous riparian zones than hemlock riparian zones. Controlled shading reduced chlorophyll a, while excluding grazing yielded inconclusive results. Periphyton biomass in Egypt Brook was found to be light limited, and grazing did not suppress periphyton biomass. As hemlocks die, in-stream light will be significantly augmented, and periphyton biomass will increase. A challenge for stream ecologists will be to incorporate multiple physical, chemical, and biological controls on biota in order to fully understand how regional hemlock mortality will alter stream periphyton biomass.

openCC (other)Mar 2025View details →

Soil nitrogen availability vs. acidification: effects on soil respiration, heterotrophic respiration, and soil physicochemical properties in mixed temperate forests in central New York, USA (2019-2022)

In 2011, an experimental nitrogen x pH manipulation study was initiated in mixed temperate forests in central New York, USA to disentangle the often-confounded roles of nitrogen (N) and soil pH in driving various ecosystem processes. This data package contains soil physicochemical properties (soil pH, resin available nitrogen), soil temperature, in situ soil respiration, and heterotrophic respiration measured from laboratory incubations of soils collected from experimental plots. Soil pH was measured both pre-treatment (2009-2010) and after 8 and 11 years of experimental treatment. All other properties were measured between 9 and 12 years after treatment initiation.

openCC0Jul 2021View details →

Long-term monitoring of ground-dwelling arthropods in central Arizona-Phoenix, ongoing since 1998 (Reformatted to the ecocomDP Design Pattern)

This data package is formatted as an ecocomDP (Ecological Community Data Pattern). For more information on ecocomDP see https://github.com/EDIorg/ecocomDP. This Level 1 data package was derived from the Level 0 data package found here: https://pasta.lternet.edu/package/metadata/eml/knb-lter-cap/41/16. The abstract below was extracted from the Level 0 data package and is included for context: The Central Arizona–Phoenix Long-Term Ecological Research (CAP LTER) program has been monitoring ground-dwelling arthropods (e.g., insects, ararchnids) at locations throughout the greater Phoenix metropolitan area (GPMA) and surrounding Sonoran desert region since 1998. Monitoring locations span a diversity of habitat types, including mesic and xeric residential yards, commercial areas, agricultural fields, desert locations within the GPMA (desert remnant), and undisturbed desert locations. Organisms are collected quarterly using unbaited pitfall traps, typically ten per location but with some variation, exposed for approximately seventy-two hours. Organisms are identified to the lowest practical taxonomic level and enumerated. Many of the sampling locations established at the beginning of the monitoring project were relocated in 2001-2002 to overlap with the CAP LTER’s Ecological Survey of Central Arizona (ESCA; formerly named Survey200) long-term monitoring sites, although within the same general landscape categories.

openCC0Sep 2024View details →

Fish Food on Floodplain Farm Fields, California Central Valley, Seasons 2019 and 2021

2019 Water Year (October 1, 2018 through September 30, 2019) In the winter and spring of 2018-2019, 5,000 acres of agricultural land in Yolo County, California was intentionally flooded. These “dry-side” rice fields, although on the former floodplain of the Sacramento River, are separated from the fish-bearing Sacramento River (the “wet-side”) by high flood levees. Today, levees cut off 95% of the Central Valley’s floodplains from river channels so that Central Valley aquatic ecosystems no longer recruit floodplain the food web resources needed to support robust aquatic food webs, create fish biomass and sustain abundant fish populations. In this experiment we asked whether floodplain food web resources “grown” in intentionally inundated “dry-side” agricultural fields could be exported back to the river via flood drainage infrastructure. If so, we were interested to know whether those resources could improve juvenile salmon foraging success and increase growth rates. In order to test these questions, we caged fish in the floodplain drainage canal, at the location where the floodplain drainage water entered the river and at locations both up- and downstream. We hypothesized that zooplankton abundance and fish growth rates would be elevated at the managed floodplain outfall location, relative to the upstream location. We measured water quality parameters, zooplankton species assemblage and abundance, and juvenile Chinook salmon growth rates with PIT tagged, hatchery-origin fish confined to enclosures at the study locations. The 5,000 acres of managed floodplain was drained over the coarse of 5 weeks in February and March, 2019 at a maximum rate of 1,000 cfs. The Sacramento River flow during the experiment ranged from 20,000-30,000 cfs. Fish growth rates at the floodplain outfall location were up to five times greater than growth rates upstream of the outfall and enclosure fish experienced growth rate benefits at least up to a mile downstream from the managed floodplai

openCC0Jul 2025View details →

CAP LTER weather stations at Papago Park and Lost Dutchman State Park in the greater Phoenix metropolitan area of central Arizona, USA, ongoing since 2010

The CAP LTER maintains two micrometeorological stations (10-m height) in the greater Phoenix metropolitan area, including at Lost Dutchman State Park and near the Desert Botanical Garden at Papago Park. The local terrain at both sites is flat or gently sloping Sonoran desert, and the vegetation canopy consists of patchy coverage of desert shrubs and trees. The dominant vegetation species include bursage (*Ambrosia deltoidea*) and creosote bush (*Larrea tridentata*), while minor species include palo verde (*Parkinsonia microphylla*) and saguaro cactus (*Carnegiea gigantea*). Wind speed and direction, incoming solar radiation, air temperature, relative humidity, and precipitation have been monitored nearly continuously since the fall of 2010. Each variable is measured every 5 seconds and the average (or total for precipitation and total solar radiation) saved to a data logger every 10 minutes.