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99 results for “Chronosequence”
From bottom-up to top-down control of invertebrate herbivores in a retrogressive chronosequence
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Data from: Quantifying seed rain patterns in a remnant and a chronosequence of restored tallgrass prairies in north central Missouri
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Lichen abundance and biodiversity along a chronosequence from young managed stands to ancient forest, 1993 (Neitlich thesis)
The diversity of epiphytic lichens in old growth forests has stimulated considerable research (e.g., Howe 1978, Pike et al. 1975; Hoffman and Kazmierski 1969). We possess few data on the lichen communities of younger stands or the manner in which they develop as the forest ages. As our society grapples with the consequences of habitat loss and pressure on existing natural populations, such data are acutely needed (FEMAT 1993). This paper seeks to describe the relationship between forest age and the abundance and diversity of lichens in one region, and in doing so, to invite more rigorous assessment of the conservation needs of lichens with respect to forest management. Moveover, that documenting these patterns will facilitate research into age- related processes directly influencing lichen abundance and diversity.
Spatial patterns of understory vegetation and soil in an Alaskan upland boreal forest fire chronosequence. Three sites located in Delta Junction Alaska. Soil sampled during summer 2007
In this study we used geostatistics to characterize the spatial heterogeneity of soil carbon and nitrogen pools, microbial respiration, microbial biomass, nitrogen mineralization, soil moisture, soil pH, depth of organic horizon and forest floor covers and understory vegetation abundances in three sites (1999, 1987 and 1920 wildfires) of a boreal forest chronosequence of Interior Alaska (near Delta Junction). Soil sampling and vegetation measurements occured during summer 2007.
A Chronosequence of Biomass and Carbon and Nitrogen Stocks Across Boreal Deciduous, Mixed, and Black Spruce Forests in Interior Alaska
This dataset contains forest structure data and estimates of above- and belowground carbon and nitrogen pools for a chronosequence of sites that vary in time after fire. Sites are spread throughout interior Alaska and were selected to represent the range of forest composition, from black spruce (Picea mariana) dominance, to deciduous tree dominance (Betula neoalaskana and Populus tremuloides). Multiple transects were measured in each site
Core Old Field Grasshopper Sampling:Successional Dynamics on a Resampled Chronosequence
The purpose of this observational study is to describe the dynamics of ecosystem succession. The change in the number, type, and amount of plant and grazing animal species is monitored in more than 20 fields. These fields were previously cultivated, but then abandoned from agriculture at various times in the past. The fields were left undisturbed for plants to develop from seeds within the soil or brought into the fields by wind or animals. Permanent transects have been established in these abandoned fields for purposes of sampling in a consistent location from year to year. Permanent plots along these transects have been used to sample soil nutrients, (in particular, nitrogen) abundance of vegetation, species composition and herbivore populations. The sampling occurs approximately every 6 years. In the initial survey, 100 quadrats of size 1 by 0.5 m were sampled per field in 23 different fields. Abandoned fields included in E014 are 4, 5, 10, 21, 24, 26, 27, 28, 32, 35, 39, 40, 41, 44, 45, 47, 53, 70, 72, 76, 77. Fields 22(B), 29(A), and 69(C) were originally included in E014 but used for other purposes shortly after the start of the study. This experiment was established in 1983 and 1989 by principal investigators Johannes Knops and David Tilman. Past work at CDR and elsewhere has demonstrated an overriding influence of fire frequency in maintaining prairie openings and oak savanna at the prairie-forest border. Fire regimes harm some types of species while favoring others and drive light and nutrient dynamics, which in turn drive community functional attributes and diversity levels. Ultimately, fire frequency interacts with climate, N deposition, land use, and biotic invasion to determine the outcomes of tree-grass interactions and the dynamics of vegetation at ecotones such as the prairie-forest border in Minnesota. In 2006 each field was divided in half, and one half randomly chosen for periodic prescribed burning (a fire every other year). We anticipate that th
Supplemental Old Field Grasshopper Sampling:Successional Dynamics on a Resampled Chronosequence
The purpose of this observational study is to describe the dynamics of ecosystem succession. The change in the number, type, and amount of plant and grazing animal species is monitored in more than 20 fields. These fields were previously cultivated, but then abandoned from agriculture at various times in the past. The fields were left undisturbed for plants to develop from seeds within the soil or brought into the fields by wind or animals. Permanent transects have been established in these abandoned fields for purposes of sampling in a consistent location from year to year. Permanent plots along these transects have been used to sample soil nutrients, (in particular, nitrogen) abundance of vegetation, species composition and herbivore populations. The sampling occurs approximately every 6 years. In the initial survey, 100 quadrats of size 1 by 0.5 m were sampled per field in 23 different fields. Abandoned fields included in E014 are 4, 5, 10, 21, 24, 26, 27, 28, 32, 35, 39, 40, 41, 44, 45, 47, 53, 70, 72, 76, 77. Fields 22(B), 29(A), and 69(C) were originally included in E014 but used for other purposes shortly after the start of the study. This experiment was established in 1983 and 1989 by principal investigators Johannes Knops and David Tilman. Past work at CDR and elsewhere has demonstrated an overriding influence of fire frequency in maintaining prairie openings and oak savanna at the prairie-forest border. Fire regimes harm some types of species while favoring others and drive light and nutrient dynamics, which in turn drive community functional attributes and diversity levels. Ultimately, fire frequency interacts with climate, N deposition, land use, and biotic invasion to determine the outcomes of tree-grass interactions and the dynamics of vegetation at ecotones such as the prairie-forest border in Minnesota. In 2006 each field was divided in half, and one half randomly chosen for periodic prescribed burning (a fire every other year). We anticipate that th
In situ soil N mineralization in gopher mounds and soil under gopher mounds:Experiment 014 - Successional Dynamics on a Resampled Chronosequence
The purpose of this observational study is to describe the dynamics of ecosystem succession. The change in the number, type, and amount of plant and grazing animal species is monitored in more than 20 fields. These fields were previously cultivated, but then abandoned from agriculture at various times in the past. The fields were left undisturbed for plants to develop from seeds within the soil or brought into the fields by wind or animals. Permanent transects have been established in these abandoned fields for purposes of sampling in a consistent location from year to year. Permanent plots along these transects have been used to sample soil nutrients, (in particular, nitrogen) abundance of vegetation, species composition and herbivore populations. The sampling occurs approximately every 6 years. In the initial survey, 100 quadrats of size 1 by 0.5 m were sampled per field in 23 different fields. Abandoned fields included in E014 are 4, 5, 10, 21, 24, 26, 27, 28, 32, 35, 39, 40, 41, 44, 45, 47, 53, 70, 72, 76, 77. Fields 22(B), 29(A), and 69(C) were originally included in E014 but used for other purposes shortly after the start of the study. This experiment was established in 1983 and 1989 by principal investigators Johannes Knops and David Tilman. Past work at CDR and elsewhere has demonstrated an overriding influence of fire frequency in maintaining prairie openings and oak savanna at the prairie-forest border. Fire regimes harm some types of species while favoring others and drive light and nutrient dynamics, which in turn drive community functional attributes and diversity levels. Ultimately, fire frequency interacts with climate, N deposition, land use, and biotic invasion to determine the outcomes of tree-grass interactions and the dynamics of vegetation at ecotones such as the prairie-forest border in Minnesota. In 2006 each field was divided in half, and one half randomly chosen for periodic prescribed burning (a fire every other year). We anticipate that th
Aboveground biomass on and around gopher mounds 2017:Experiment 014 - Successional Dynamics on a Resampled Chronosequence
The purpose of this observational study is to describe the dynamics of ecosystem succession. The change in the number, type, and amount of plant and grazing animal species is monitored in more than 20 fields. These fields were previously cultivated, but then abandoned from agriculture at various times in the past. The fields were left undisturbed for plants to develop from seeds within the soil or brought into the fields by wind or animals. Permanent transects have been established in these abandoned fields for purposes of sampling in a consistent location from year to year. Permanent plots along these transects have been used to sample soil nutrients, (in particular, nitrogen) abundance of vegetation, species composition and herbivore populations. The sampling occurs approximately every 6 years. In the initial survey, 100 quadrats of size 1 by 0.5 m were sampled per field in 23 different fields. Abandoned fields included in E014 are 4, 5, 10, 21, 24, 26, 27, 28, 32, 35, 39, 40, 41, 44, 45, 47, 53, 70, 72, 76, 77. Fields 22(B), 29(A), and 69(C) were originally included in E014 but used for other purposes shortly after the start of the study. This experiment was established in 1983 and 1989 by principal investigators Johannes Knops and David Tilman. Past work at CDR and elsewhere has demonstrated an overriding influence of fire frequency in maintaining prairie openings and oak savanna at the prairie-forest border. Fire regimes harm some types of species while favoring others and drive light and nutrient dynamics, which in turn drive community functional attributes and diversity levels. Ultimately, fire frequency interacts with climate, N deposition, land use, and biotic invasion to determine the outcomes of tree-grass interactions and the dynamics of vegetation at ecotones such as the prairie-forest border in Minnesota. In 2006 each field was divided in half, and one half randomly chosen for periodic prescribed burning (a fire every other year). We anticipate that th
Gopher mounds coordinates on a Resampled Chronosequence
Soil carbon (C) sequestration rates vary widely in abandoned agricultural lands, and factors determining this variation, beyond climate, soil type, and productivity, are poorly understood. One such factor is soil disturbance by burrowing mammals. Despite being ubiquitous in all grasslands, the impact of burrowing mammals on soil C dynamics is not well understood. We quantified the major ecosystem processes that are influenced by one such burrowing mammal, plains pocket gophers (Geomys bursarius), in old field ecosystems located in east-central Minnesota, USA. We found pocket gopher abundance varied among old fields, and newly formed gopher mounds covered up to 6% of the soil surface annually. We first measured short-term C pools and fluxes changes induced by gopher activities. Soil N mineralization did not differ between the soil in gopher mounds and undisturbed soil. However, for the soil under gopher mounds, N mineralization was 30% lower as compared to the undisturbed soil. We developed a process model to simulate the long-term gopher disturbance impact on old field soil C accumulation. This simulation showed that pocket gophers reduce both the rate of soil C accumulation and the total C pool. This reduction is primarily driven by reduced plant C input due to the time it requires for the vegetation to recolonize gopher mounds. Soil organic matter (SOM) decomposition changes had only a minor impact. The process model showed that the depth from which burrowing mammals redistribute soil to the surface is a key factor determining the overall impact on SOM. In total, our study indicates that soil disturbance by burrowing animals can significantly reduce C storage in old field ecosystems when the mammals are mostly active in surface soil and can be a significant factor in decreasing overall C sequestration after land abandonment. However, at our study site, gopher abundance decreases with abandonment age, likely cause by successional vegetation changes, thus the gopher
Fine root production on Hog Island chronosequence at the Virginia Coast Reserve . 1991
The data include live fine roots (less than or equal to 2 mm diameter). Root growth was sampled at 10, 20, 30 and 40 cm depth. All data are in g/meter square/year. Fine roots were extracted along a chronosequence of barrier island and dune communities.
Photosynthetic capacity and electron transport rate for a chronosequence of shrub thickets on Hog Island, VA , 2012
Photosynthetic capacity and electron transport rate (ETR) was assessed for Morella cerifera shrubs at 4 sites ranging in age from 10 to 50 years on Hog Island, VA during June and July 2012 using a pulse amplitude modulated (PAM) leaf fluorometer.
Fine Root Biomass on North Hog Chronosequence, Virginia Coast Reserve, 1991-1992
A sequential coring method was used to determine live fine-root biomass (LFRB) along a barrier island dune and swale chronosequence on Hog Island, VA, between February 1991 and February 1992.
A 249-year chronosequence of forest plots from eight successive fires in the eastern Canada boreal mixedwoods
<p>A combination of wildfires and defoliating insect outbreaks play an important role in the natural successional dynamics of North American boreal forests, which, in the long term, change the post-disturbance composition and structure of forest stands. After stand-replacing disturbances (mainly wildfires), early successional hardwoods typically dominate the affected areas in boreal forests. Provided sufficient time following disturbances, the increasing recruitment of mid- to late-successional softwoods as well as the mortality of hardwoods gradually change forest composition from hardwoods to admixtures of hardwood-conifer species and conifer-dominated stands in mid and late successional stages, respectively. Such mixed woods are abundant across the southern Canadian boreal forest. In boreal Canada, mixed woods are the most structurally heterogeneous forest ecosystems, are highly productive, and form an important source of timber supply. Here we present the EASTERN BOREAL MIXEDWOODS CANADA dataset, which documents the changes in composition and structure of stands originating from eight successive wildfires representing a chronosequence of 249 years in eastern Canada. This dataset has been used in several different projects to study and model the influence of natural (e.g., insect outbreaks) and anthropogenic disturbances (e.g., harvesting) on the dynamics of post-fire stands. The data covers a high range of variability in stand composition and structure, explained by species establishment, dominance and mixture. It thus constitutes a useful source of information to trace the dynamics of the main boreal tree species of eastern north America, from their establishment to their replacement at different spatial scales (e.g., from stand to landscape level).</p>
Data from: High specialization and limited structural change in plant‐herbivore networks along a successional chronosequence in tropical montane forest
Secondary succession is well‐understood, to the point of being predictable for plant communities, but the successional changes in plant‐herbivore interactions remains poorly explored. This is particularly true for tropical forests, despite the increasing importance of early successional stages in tropical landscapes. Deriving expectations from successional theory, we examine properties of plant‐herbivore interaction networks while accounting for host phylogenetic structure along a succession chronosequence in montane rainforest in Papua New Guinea. We present one of the most comprehensive successional investigations of interaction networks, equating to >40 person years of field sampling, and one of the few focused on montane tropical forests. We use a series of nine 0.2ha forest plots across young secondary, mature secondary and primary montane forest, sampled almost completely for woody plants and larval leaf chewers (Lepidoptera), using forest felling. These networks comprised of 12,357 plant‐herbivore interactions and were analysed using quantitative network metrics, a phylogenetically controlled host‐use index and a qualitative network beta diversity measure. Network structural changes were low and specialisation metrics surprisingly similar throughout succession, despite high network beta diversity. Herbivore abundance was greatest in the earliest stages, and hosts here had more species‐rich herbivore assemblages, presumably reflecting higher palatability due to lower defensive investment. All herbivore communities were highly specialised, using a phylogenetically narrow set of hosts, while host phylogenetic diversity itself decreased throughout the chronosequence. Relatively high phylogenetic diversity, and thus high diversity of plant defenses, in early succession forest may result in herbivores feeding on fewer hosts than expected. Successional theory, derived primarily from temperate systems, is limited in predicting tropical host‐herbivore interactions. All succession stages harbour diverse and unique interaction networks, which together with largely similar network structures and consistent host use patterns, suggests general rules of assembly may apply to these systems.
Plant trait matrix for fire-prone Mediterranean chronosequences
<p>A database of 23 traits for 117 Mediterranean plant species. It includes three groups of traits: i) four whole-plant traits (bud height, sclerophylly, xerophily and resprouting ability), ii) ten above-ground traits (plant height, flowering time and span, leaf size, area, weight, thickness, specific leaf area, seed size and dispersal distance), and iii) nine below-ground traits (root length, depth, laterality, root depth:laterality ratio, root weight, specific root length, root C and N concentration and the root CN ratio).</p>
Raw data: Stable isotopes of Hawaiian spiders reflect substrate properties along a chronosequence
<p>Data sets used to analyze N and C stable isotope ratios in spider tissues, leaf litter, and plant leaves originating from three sites along a substrate age gradient in Hawaii.</p>
Cryoturbation leads to iron-organic carbon associations along a permafrost soil chronosequence in northern Alaska
<p>In permafrost soils, substantial amounts of organic carbon (OC) are potentially protected from microbial degradation and transformation into greenhouse gases by association with reactive iron (Fe) minerals. As permafrost environments respond to climate change, increased drainage of thaw lakes in permafrost regions is predicted. Soils will subsequently develop on these drained thaw lakes, but the role of Fe-OC associations in future OC stabilization during this predicted soil development is unknown. To fill this knowledge gap, we have examined Fe-OC associations in organic, cryoturbated and mineral horizons along a 5500-year chronosequence of drained thaw lake basins in Utqiaġvik, Alaska. By applying chemical extractions, we found that ~17 % of the total OC content in cryoturbated horizons is associated with reactive Fe minerals, compared to ~10 % in organic or mineral horizons. As soil development advances, the total stocks of Fe-associated OC more than double within the first 50 years after thaw lake drainage, because of increased storage of Fe-associated OC in cryoturbated horizons (from 8 to 75 % of the total Fe-associated OC stock). Spatially-resolved nanoscale secondary ion mass spectrometry showed that OC is primarily associated with Fe(III) (oxyhydr)oxides which were identified by <sup>57</sup>Fe Mössbauer spectroscopy as ferrihydrite. High OC:Fe mass ratios (>0.22) indicate that Fe-OC associations are formed via co-precipitation, chelation and aggregation. These results demonstrate that, given the proposed enhanced drainage of thaw lakes under climate change, OC is increasingly incorporated and stabilized by the association with reactive Fe minerals as a result of soil formation and increased cryoturbation.</p>
Sequencing data for: Chronosequence of invasion reveals minimal losses of population genomic diversity, niche expansion, and trait divergence in the polyploid, leafy spurge
<p>Rapid evolution may play an important role in the range expansion of invasive species and modify forecasts of invasion, which are the backbone of land management strategies. However, losses of genetic variation associated with colonization bottlenecks may constrain trait and niche divergence at leading range edges, thereby impacting management decisions that anticipate future range expansion. The spatial and temporal scales over which adaptation contributes to invasion dynamics remain unresolved. We leveraged detailed records of the ~130-year invasion history of the invasive polyploid plant, leafy spurge (<em>Euphorbia</em> <em>virgata</em>), across ~500km in Minnesota, U.S.A. We examined the consequences of range expansion for population genomic diversity, niche breadth, and the evolution of germination behavior. Using genotyping-by-sequencing, we found some population structure in the range core, where introduction occurred, but panmixia among all other populations. Range expansion was accompanied by only modest losses in sequence diversity, with small, isolated populations at the leading edge harboring similar levels of diversity to those in the range core. The climatic niche expanded during most of the range expansion, and the niche of the range core was largely non-overlapping with the invasion front. Ecological niche models indicated that mean temperature of the warmest quarter was the strongest determinant of habitat suitability and that populations at the leading edge had the lowest habitat suitability. Guided by these findings, we tested for rapid evolution in germination behavior over the time course of range expansion using a common garden experiment and temperature manipulations. Germination behavior diverged from early to late phases of the invasion, with populations from later phases having higher dormancy at lower temperatures. Our results suggest that trait evolution may have contributed to niche expansion during invasion and that distribution models, which inform future management planning, may underestimate invasion potential without accounting for evolution.</p>
Setting the benchmark: Patterns of forest structure after wildfire in temperate, montane forests across a multi-century chronosequence
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