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At least 865 records · Page 48Linked to original sources

USGS2021

Concentrations, loads, and associated trends of nutrients entering the Sacramento-San Joaquin Delta, California

Statistical modeling of water-quality data collected at the Sacramento River at Freeport and San Joaquin River near Vernalis, California, USA, was used to examine trends in concentrations and loads of various forms of dissolved and particulate nitrogen and phosphorus that entered the Sacramento–San Joaquin River Delta (Delta) from upstream sources between 1970 and 2019. Ammonium concentrations and loads decreased at the Sacramento River site from the mid-1970s through 1990 because of the consolidation of wastewater treatment and continuously reduced from the mid-1970s to 2019 at the San Joaquin River site. Current ammonium concentrations are mostly below 4 µM (0.056 mg N L –1 ) at both sites, a concentration above which reductions in phytoplankton productivity or changes in algal species composition may occur. The Sacramento River at Freeport site is located upstream of the Sacramento Regional County Sanitation District’s treatment facility’s discharge point; nutrient water quality there is representative of upstream sources. Inorganic nitrogen (nitrate plus ammonium) concentrations and loading differed at both sites. At the Sacramento River location, concentrations decrease in the summer agricultural season, reducing the molar ratios of nitrogen to phosphorus. In contrast, inorganic nitrogen concentrations increase in the San Joaquin River during the agricultural season as a result of irrigation runoff, increasing the molar ratio of nitrogen to phosphorus. This increase suggests a possible nitrogen limitation in the northern Delta and a phosphorus limitation in the southern Delta, as indicated by the molar ratios of bioavailable nitrogen to bioavailable phosphorus. Planned upgrades to the Sacramento Regional Wastewater Treatment Plant (SRWTP) will reduce inorganic nitrogen inputs to the northern Delta. Consequently, the supply of bioavailable nitrogen throughout the upper estuary should diminish. Source modeling of nitrogen and phosphorus identifies agriculture, atmospheric deposition, and wastewater effluent as sources of total nitrogen in the Central Valley. In contrast, geologic sources, agriculture, and wastewater discharge are the primary sources of phosphorus.

California↗

USGS1949

Trends in the lake trout fishery of Lake Huron through 1946

The production of lake trout, Cristivomer namaycush (Walbaum), in the United States waters of Lake Huron was highest in the earliest years for which there are statistical records, averaging 2,362,000 pounds in 1879–1894. The general level of yield was much lower but relatively stable in 1895–1939, during which period the catch averaged 1,685,000 pounds. The most recent years have seen a rapid and calamitous decline in the output; setting a new record low each year, the take decreased from 940,000 pounds in 1940 to only 38,000 pounds in 1946. The production of lake trout in the Canadian waters of Lake Huron was generally low from 1867 up to about 1883, apparently because the fishery was then in the process of development. After 1882 the yield was relatively high for 26 years and then fell away progressively as the following averages of production in pounds for different periods show: (1883–1908) Huron proper–1,749,000, Georgian Bay (including the North Channel)–2,475,000, Canadian total–4,224,000; (1909–1922) Canadian total (no data for regions within the lake)–3,753,000; (1923–1939) Huron proper–1,600,000, Georgian Bay–1,996,000, Canadian total–3,596,000. During more recent years the catch fell from 1,038,000 pounds in 1940 to 29,000 pounds in 1946 in Huron proper, from 1,688,000 to 702,000 pounds in Georgian Bay, and from 2,726,000 to 731,000 pounds in all Canadian waters. The tremendous decreases in production that have occurred in all parts of Lake Huron in recent years are generally believed to have been caused by a reduction in the abundance of lake trout resulting from attacks by the sea lamprey, which has become established and has multiplied rapidly in the upper Great Lakes. Data are available on the production of lake trout in six local regions or statistical districts of the United States waters of Lake Huron (boundaries shown in Fig. 1) in 1891–1908 and on production, fishing intensity, and the abundance of fish on the grounds in 1929–1946. The order of the districts with respect to their percentage contribution to the average annual production was the same in 1891–1908 and 1929–1943. Certain changes occurred, nevertheless, in all percentages. The northern districts (H-1, H-2) which contributed 70.3 percent of the take in 1891–1908 accounted for only 56.2 percent in 1929–1943 whereas the central (H-3, H-4) and southern (H-5, H-6) districts which yielded 18.7 and 11.0 percent, respectively, in the former period contributed 25.5 and 18.3 percent in the latter. The six districts were similar in 1929–1946 in that in all of them (1) most of the years of highest output and of most intensive fishing occurred in the early to middle 1930′s and (2) the earlier high levels were followed by declines that ultimately reduced production and fishing intensity to insignificance. The same (earlier high values followed by a decline) held for the abundance of lake trout in the northerly five districts, but the trends of fluctuation in the abundance in H-6 were opposite those in other areas. On the whole, the abundance of lake trout appeared to have little effect on fishing intensity for the species. Only in H-1 did the two exhibit significant positive correlation whereas in H-6 they showed highly significant negative correlation. Most of the factors that may counteract the expected influence of abundance on fishing intensity (economic conditions, weather, …) cannot be evaluated accurately. It was determined, however, that the collapse of the whitefish fishery in the middle and late 1930′s most probably exerted a significant depressing effect on the intensity of the gill-net fishery for lake trout in those districts (H-1, H-4, H-6) in which the two species are ordinarily captured together. The estimated abundance of lake trout in the United States waters of Lake Huron (all districts combined) had reached an extremely low level in 1946 (24 percent of the 1929–1943 average), and the complete collapse of the fishery in late years is a matter of record. The rate of decline in abundance, however, was much less rapid than the spectacular decreases in production might suggest. Although each year beginning with 1940 saw a new record low yield, the abundance was still 87 percent of average in 1942 and did not drop below 70 percent until 1944. This seeming paradox is explained by the fact that relative to average conditions, fishing intensity in 1941–1946 was lower and was decreasing much more rapidly than was abundance. PDF

Transactions of the American Fisheries Society↗

USGS2011

Trends in relative weight of walleye stocks in Wyoming reservoirs

The relative weight ( W r ) index of body condition provided insight into the stock dynamics of walleye Stizostedion vitreum in six reservoirs in the North Platte River drainage of Wyoming. The three most upstream reservoirs are managed as both walleye and trout ( Oncorhynchus spp. and Salmo spp.) fisheries; trout are stocked annually. The three downstream reservoirs are managed for coolwater and warmwater fishes, and walleye fry are stocked almost annually in two of the reservoirs. Positive relations between stocking densities of trout and W r of walleyes and between water levels and W r of walleyes were observed. Length-related trends in W r within walleye stocks over time were related to prey availability.

Wyoming↗

USGS2002

Double sampling to estimate density and population trends in birds

We present a method for estimating density of nesting birds based on double sampling. The approach involves surveying a large sample of plots using a rapid method such as uncorrected point counts, variable circular plot counts, or the recently suggested double-observer method. A subsample of those plots is also surveyed using intensive methods to determine actual density. The ratio of the mean count on those plots (using the rapid method) to the mean actual density (as determined by the intensive searches) is used to adjust results from the rapid method. The approach works well when results from the rapid method are highly correlated with actual density. We illustrate the method with three years of shorebird surveys from the tundra in northern Alaska. In the rapid method, surveyors covered ~10 ha h -1 and surveyed each plot a single time. The intensive surveys involved three thorough searches, required ~3 h ha -1 , and took 20% of the study effort. Surveyors using the rapid method detected an average of 79% of birds present. That detection ratio was used to convert the index obtained in the rapid method into an essentially unbiased estimate of density. Trends estimated from several years of data would also be essentially unbiased. Other advantages of double sampling are that (1) the rapid method can be changed as new methods become available, (2) domains can be compared even if detection rates differ, (3) total population size can be estimated, and (4) valuable ancillary information (e.g. nest success) can be obtained on intensive plots with little additional effort. We suggest that double sampling be used to test the assumption that rapid methods, such as variable circular plot and double-observer methods, yield density estimates that are essentially unbiased. The feasibility of implementing double sampling in a range of habitats needs to be evaluated.

The Auk↗

USGS2008

Trends in abundance of collared lemmings near Cape Churchill, Manitoba, Canada

Regular, multiannual cycles observed in the population abundance of small mammals in many arctic and subarctic ecosystems have stimulated substantial research, particularly among population ecologists. Hypotheses of mechanisms generating regular cycles include predator-prey interactions, limitation of food resources, and migration or dispersal, as well as abiotic factors such as cyclic climatic variation and environmental stochasticity. In 2004 and 2005, we used indirect methods to estimate trends in population size of Richardson's collared lemmings (Dicrostonyx richardsoni) retrospectively, and evaluated the extent of synchrony between lemming populations at 2 coastal tundra study areas separated by approximately 60 km near Cape Churchill, Manitoba, Canada. We collected scars on willow plants (Salix) resulting from lemming feeding. Ages of scars ranged from 0 to 13 years at both study areas. Scar-age frequency appeared cyclic and we used nonlinear Poisson regression to model the observed scar-age frequency. Lemming populations cycled with 2.8-year periodicity and the phase of the cycle was synchronous between the 2 study areas. We suggest that our approach could be applied in multiple settings and may provide the most efficient way to gather data on small mammals across both space and time in a diversity of landscapes. ?? 2008 American Society of Mammalogists.

Journal of Mammalogy↗

USGS2003

Estimating population trends with a linear model

We describe a simple and robust method for estimating trends in population size. The method may be used with Breeding Bird Survey data, aerial surveys, point counts, or any other program of repeated surveys at permanent locations. Surveys need not be made at each location during each survey period. The method differs from most existing methods in being design based, rather than model based. The only assumptions are that the nominal sampling plan is followed and that sample size is large enough for use of the t-distribution. Simulations based on two bird data sets from natural populations showed that the point estimate produced by the linear model was essentially unbiased even when counts varied substantially and 25% of the complete data set was missing. The estimating-equation approach, often used to analyze Breeding Bird Survey data, performed similarly on one data set but had substantial bias on the second data set, in which counts were highly variable. The advantages of the linear model are its simplicity, flexibility, and that it is self-weighting. A user-friendly computer program to carry out the calculations is available from the senior author.

The Condor↗

USGS2004

Estimating population trends with a linear model: Technical comments

Controversy has sometimes arisen over whether there is a need to accommodate the limitations of survey design in estimating population change from the count data collected in bird surveys. Analyses of surveys such as the North American Breeding Bird Survey (BBS) can be quite complex; it is natural to ask if the complexity is necessary, or whether the statisticians have run amok. Bart et al. (2003) propose a very simple analysis involving nothing more complicated than simple linear regression, and contrast their approach with model-based procedures. We review the assumptions implicit to their proposed method, and document that these assumptions are unlikely to be valid for surveys such as the BBS. One fundamental limitation of a purely design-based approach is the absence of controls for factors that influence detection of birds at survey sites. We show that failure to model observer effects in survey data leads to substantial bias in estimation of population trends from BBS data for the 20 species that Bart et al. (2003) used as the basis of their simulations. Finally, we note that the simulations presented in Bart et al. (2003) do not provide a useful evaluation of their proposed method, nor do they provide a valid comparison to the estimating- equations alternative they consider.

Condor↗

USGS2009

Mast and weather influences on population trends of a species of concern: The allegheny woodrat

Over the past 20-30 y. northern and western populations of the Allegheny woodrat (Neotoma magister) have experienced large declines. whereas populations in the core of the range are assumed to be stable. We examined population trends at two study areas in northcentral West Virginia along the western ridge of the central Appalachian Mountains. Temperature and precipitation parameters along with mast production were examined to determine if these environmental variables impacted the population. Based on a 5 y dataset. our results indicate a yearly decrease in the overall population. with adult females most affected. Hard and soft mast availability related to adult female capture rates. whereas temperatures significantly affected juvenile. adult female and overall capture rates. Juvenile summer capture rates increased with warmer temperatures the preceding winter. Female summer capture rates decreased with warmer temperatures the preceding spring suggesting that effects of warming should be added as a potential threat to the Allegheny woodrat.

American Midland Naturalist↗

USGS2014

Below the disappearing marshes of an urban estuary: historic nitrogen trends and soil structure

Marshes in the urban Jamaica Bay Estuary, New York, USA are disappearing at an average rate of 13 ha/yr, and multiple stressors (e.g., wastewater inputs, dredging activities, groundwater removal, and global warming) may be contributing to marsh losses. Among these stressors, wastewater nutrients are suspected to be an important contributing cause of marsh deterioration. We used census data, radiometric dating, stable nitrogen isotopes, and soil surveys to examine the temporal relationships between human population growth and soil nitrogen; and we evaluated soil structure with computer-aided tomography, surface elevation and sediment accretion trends, carbon dioxide emissions, and soil shear strength to examine differences among disappearing (Black Bank and Big Egg) and stable marshes (JoCo). Radiometric dating and nitrogen isotope analyses suggested a rapid increase in human wastewater nutrients beginning in the late 1840s, and a tapering off beginning in the 1930s when wastewater treatment plants (WWTPs) were first installed. Current WWTPs nutrient loads to Jamaica Bay are approximately 13 995 kg N/d and 2767 kg P/d. At Black Bank, the biomass and abundance of roots and rhizomes and percentage of organic matter on soil were significantly lower, rhizomes larger in diameter, carbon dioxide emission rates and peat particle density significantly greater, and soil strength significantly lower compared to the stable JoCo Marsh, suggesting Black Bank has elevated decomposition rates, more decomposed peat, and highly waterlogged peat. Despite these differences, the rates of accretion and surface elevation change were similar for both marshes, and the rates of elevation change approximated the long term relative rate of sea level rise estimated from tide gauge data at nearby Sandy Hook, New Jersey. We hypothesize that Black Bank marsh kept pace with sea level rise by the accretion of material on the marsh surface, and the maintenance of soil volume through production of larger diameter rhizomes and swelling (dilation) of waterlogged peat. JoCo Marsh kept pace with sea-level rise through surface accretion and soil organic matter accumulation. Understanding the effects of multiple stressors, including nutrient enrichment, on soil structure, organic matter accumulation, and elevation change will better inform management decisions aimed at maintaining and restoring coastal marshes.

New York↗

USGS2010

Spatial trends in tidal flat shape and associated environmental parameters in South San Francisco Bay

Spatial trends in the shape of profiles of South San Francisco Bay (SSFB) tidal flats are examined using bathymetric and lidar data collected in 2004 and 2005. Eigenfunction analysis reveals a dominant mode of morphologic variability related to the degree of convexity or concavity in the cross-shore profileindicative of (i) depositional, tidally dominant or (ii) erosional, wave impacted conditions. Two contrasting areas of characteristic shapenorth or south of a constriction in estuary width located near the Dumbarton Bridgeare recognized. This pattern of increasing or decreasing convexity in the inner or outer estuary is correlated to spatial variability in external and internal environmental parameters, and observational results are found to be largely consistent with theoretical expectations. Tidal flat convexity in SSFB is observed to increase (in decreasing order of significance) in response to increased deposition, increased tidal range, decreased fetch length, decreased sediment grain size, and decreased tidal flat width. ?? 2010 Coastal Education and Research Foundation.

Journal of Coastal Research↗

USGS2019

A 50-year Sr/Ca time series from an enclosed, shallow-water Guam coral: In situ monitoring and extraction of a temperature trend, annual cycle, and ENSO and PDO signals

Located on the northern edge of the West Pacific Warm Pool and having a developed economy and modern infrastructure, Guam is well positioned and equipped for obtaining natural records of the west Pacific maritime paleoclimate. This study was a proof of concept to explore whether useful climate proxy records might be obtained from coral at readily accessible, even if geochemically nonoptimal, coastal sites. A 50-year Sr/Ca record (1960–2010) was thus obtained from a shallow-water, near-shore Porites lutea colony at a recreational facility inside Guam's Apra Harbor and compared with local and regional meteorological records, including the El Niño–Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO) indices. The accessibility of the site enabled documentation of relevant environmental variables for 16 months (September 2009–December 2010): seawater δ 18 O, pH, seawater cations, and nitrate. Time series of seawater δ 18 O, pH, and cations show evidence of freshwater input from direct rainfall and stream discharge into the harbor. An anomalously higher mean and variable concentrations of Ba suggest the presence of river-borne, fine-grained terrigenous sediment. Nevertheless, the Sr/Ca time series reproduces a long-term warming trend seen in historical records of local air temperature and regional sea-surface temperature (SST) and closely tracks the ENSO and PDO indices over the entire 50-year record. The consistency of the results with Guam's historical instrumental records, previous coral δ 18 O results from Guam obtained by others, and previous Sr/Ca proxy results for SST in similar environments elsewhere demonstrate that accessible near-shore sites—where environmental conditions can be monitored—can produce useful Sr/Ca records of local and regional climate phenomena.

Journal of Coastal Research↗

USGS2017

Trends and traditions: Overview and synthesis

This paper provides an overview by the editors of a collection of 25 papers for the Studies of Western Birds, to be published in a single volume by Western Field Ornithologists. The title of the volume is: "Trends and traditions: Avifaunal change in western North America."

Book chapter↗

USGS2010

Trends and transformation of nutrients and pesticides in a Coastal Plain aquifer system, United States

Four local-scale sites in areas with similar corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] agriculture were studied to determine the effects of different hydrogeologic settings of the Northern Atlantic Coastal Plain (NACP) on the transport of nutrients and pesticides in groundwater. Settings ranged from predominantly well-drained soils overlying thick, sandy surficial aquifers to predominantly poorly drained soils with complex aquifer stratigraphy and high organic matter content. Apparent age of groundwater, dissolved gases, N isotopes, major ions, selected pesticides and degradates, and geochemical environments in groundwater were studied. Agricultural chemicals were the source of most dissolved ions in groundwater. Specific conductance was strongly correlated with reconstructed nitrate (the sum of N in nitrate and N gas) (R 2 = 0.81, p < 0.0001), and is indicative of the relative degree of agricultural effects on groundwater. Trends in nitrate were primarily related to changes in manure and fertilizer use at the well-drained sites where aquifer conditions were consistently oxic. Nitrate was present in young groundwater but completely removed over time through denitrification at the poorly drained sites where there were variations in chemical input and in geochemical environment. Median concentrations of atrazine (6-chloro-N-ethyl-N'-(1- methylethyl)-1,3,5-triazine-2,4-diamine), metolachlor (2-chloro-N-(2-ethyl-6- methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide), and some of their common degradates were higher at well-drained sites than at poorly drained sites, with concentrations of degradates generally higher than those of the parent compounds at all sites. An increase in the percentage of deethylatrazine to total atrazine over time at one well-drained site may be related to changes in manure application. Copyright ?? 2010 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. All rights reserved.

Journal of Environmental Quality↗

USGS2004

Goals and strategies for estimating trends in landbird abundance

Reliable estimates of trends in population size are critical to effective management of landbirds. We propose a standard for considering that landbird populations are adequately monitored: 80% power to detect a 50% decline occuning within 20 years, using a 2-tailed test and a significance level of 0.10, and incorporating effects of potential bias. Our standard also requires that at least two-thirds of the target region be covered by the monitoring program. We recommend that the standard be achieved for species' entire ranges or for any area one-third the size of the temperate portions of Canada and the United States, whichever is smaller. We applied our approach to North American Breeding Bird Survey (BBS) data. At present, potential annual bias for the BBS is estimated at ??0.008. Further, the BBS achieves the monitoring standard for only about 42% of landbirds for which the BBS is considered the most effective monitoring approach. Achieving the proposed monitoring target for ???80% of these species would require increasing the number of BBS - or similar survey - routes by several-fold, a goal that probably is impractical. We suggest several methods for reducing potential bias and argue that if our methods are implemented, potential bias would fall to ??0.003. The required number of BBS or similar routes would then be 5,106, about 40% more than in the current BBS program. Most of the needed increases are in 15 states or provinces. Developing a comprehensive land-bird monitoring program will require increased support for coordination of the BBS (currently 2 people) and new programs for species that are poorly covered at present. Our results provide a quantitative goal for long-term land-bird monitoring and identify the sample sizes needed, within each state and province, to achieve the monitoring goal for most of the roughly 300 landbird species that are well suited to monitoring with the BBS and similar surveys.

Journal of Wildlife Management↗

USGS2005

Estimation of density and population size and recommendations for monitoring trends of Bahama parrots on Great Abaco and Great Inagua

Once abundant and widely distributed, the Bahama parrot (Amazona leucocephala bahamensis) currently inhabits only the Great Abaco and Great lnagua Islands of the Bahamas. In January 2003 and May 2002-2004, we conducted point-transect surveys (a type of distance sampling) to estimate density and population size and make recommendations for monitoring trends. Density ranged from 0.061 (SE = 0.013) to 0.085 (SE = 0.018) parrots/ha and population size ranged from 1,600 (SE = 354) to 2,386 (SE = 508) parrots when extrapolated to the 26,154 ha and 28,162 ha covered by surveys on Abaco in May 2002 and 2003, respectively. Density was 0.183 (SE = 0.049) and 0.153 (SE = 0.042) parrots/ha and population size was 5,344 (SE = 1,431) and 4,450 (SE = 1,435) parrots when extrapolated to the 29,174 ha covered by surveys on Inagua in May 2003 and 2004, respectively. Because parrot distribution was clumped, we would need to survey 213-882 points on Abaco and 258-1,659 points on Inagua to obtain a CV of 10-20% for estimated density. Cluster size and its variability and clumping increased in wintertime, making surveys imprecise and cost-ineffective. Surveys were reasonably precise and cost-effective in springtime, and we recommend conducting them when parrots are pairing and selecting nesting sites. Survey data should be collected yearly as part of an integrated monitoring strategy to estimate density and other key demographic parameters and improve our understanding of the ecological dynamics of these geographically isolated parrot populations at risk of extinction.

Wildlife Society Bulletin↗

USGS1998

Status and trends of the ashy storm-petrel on Southeast Farallon Island, California, based upon capture-recapture analyses

We conducted a capture-recapture study on the population size and trends of the Ashy Storm-petrel ( Oceanodroma homochroa ) on Southeast Farallon Island (SEFI), California, based upon data collected in 1971, 1972, and 1992. From March through August, birds were lured to fixed-site sampling locations using taped vocalization playback. Using program JOLLY, we estimated population size and evaluated statistical models using goodness-of-fit and Likelihood Ratio tests. On the southwestern slope of Lighthouse Hill, amidst prime breeding habitat, numbers of breeding birds decreased from 1,271 ± 140 (x ± SE) in 1972 to 710 ± 117 in 1992, a decline of 44% (approximate 95% CI = 22-66% decline; λ = -2.8% per annum); for a variety of reasons, we consider this to be the most reliable indicator of population change. In 1971, on a portion of SEFI relatively disjunct from the sampling area in 1972, 2,131 ± 322 breeding birds were estimated. To produce an overall early 1970s estimate with which to compare to 1992, we summed population estimates from 1971 and 1972. An overall value of 6,461 birds, of which 3,402 (53%) were breeders, was obtained for the early period. In 1992, the overall population in roughly the same area was estimated at 4,284 ± 409 birds, of which 1,990 ± 408 (46%) were presumed breeders. These results, encompassing peripheral as well as more centrally located storm-petrel habitat, indicate an overall population decline of 34% and a comparable decline in breeding birds of 42% over the past two decades. However, oceanographic conditions varied between 1971-1972 and 1992, and reduced food availability in 1992 may have influenced colony attendance and breeding effort. Nonetheless, the apparent population decline over the past 20 years suggests that the species warrants management and/or additional protective status.

Condor↗

USGS1992

Power of sign surveys to monitor population trend

The urgent need for an effective monitoring scheme for grizzly bear (Ursus arctos) populations led us to investigate the effort required to detect changes in populations of low—density dispersed animals, using sign (mainly scats and tracks) they leave on trails. We surveyed trails in Glacier National Park for bear tracks and scats during five consecutive years. Using these data, we modeled the occurrence of bear sign on trails, then estimated the power of various sampling schemes. Specifically, we explored the power of bear sign surveys to detect a 20% decline in sign occurrence. Realistic sampling schemes appear feasible if the density of sign is high enough, and we provide guidelines for designs with adequate replication to monitor long—term trends of dispersed populations using sign occurrences on trails.

Ecological Applications↗

USGS1998

The ichnologic record of the continental invertebrate invasion; evolutionary trends in environmental expansion, ecospace utilization, and behavioral complexity

The combined study of continental trace fossils and associated sedimentary facies provides valuable evidence of colonization trends and events throughout the Phanerozoic. Colonization of continental environments was linked to the exploitation of empty or under-utilized ecospace. Although the nonmarine trace fossil record probably begins during the Late Ordovician, significant invasion of nonmarine biotopes began close to the Silurian-Devonian transition with the establishment of a mobile arthropod epifauna (Diplichnites ichnoguild) in coastal marine to alluvial plain settings. Additionally, the presence of vertical burrows in Devonian high-energy fluvial deposits reflects the establishment of a stationary, deep suspension-feeding infauna of the Skolithos ichnoguild. The earliest evidence of plant-arthropod interaction occurred close to the Silurian-Devonian boundary, but widespread and varied feeding patterns are known from the Carboniferous. During the Carboniferous, permanent subaqueous lacustrine settings were colonized by a diverse, mobile detritus-feeding epifauna of the Mermia ichnoguild, which reflects a significant palaeoenvironmental expansion of trace fossils. Paleozoic ichnologic evidence supports direct routes to the land from marginal marine environments, and migration to lakes from land settings. All nonmarine sedimentary environments were colonized by the Carboniferous, and subsequent patterns indicate an increase in ecospace utilization within already colonized depositional settings. During the Permian, back-filled traces of the Scoyenia ichnoguild record the establishment of a mobile, intermediate-depth, deposit-feeding in-fauna in alluvial and transitional alluvial-lacustrine sediment. Diversification of land plants and the establishment of ecologically diverse plant communities through time provided new niches to be exploited by arthropods. Nevertheless, most ot the evolutionary feeding innovations took place relatively early, during the Late Palaeozoic or early Mesozoic. A stationary deep unfauna, the Camborygma ichnoguild, was developed in Triassic transitional alluvial-lacustrinbe deposits. Terrestrial environments hosted the rise of complex social behavioral patterns, as suggested by the probable presence of hymenopteran and isopteran nests in Triassic paleosols. An increase in diversity of trace fossils is detected in Triassic-Jurassic eolian deposits, where the ichnofauna displays more varied behavioral patterns than their Paleozoic counterparts. Also, a mobile, intermediate-depth, deposit-feeding infauna, the Vagorichnus ichnoguild, was established in deep lake environments during the Jurassic. In contrast to Paleozoic permanent subaqueous assemblages typified by surface trails, Jurassic ichnocoenoses are dominated by infaunal burrows. High density of infaunal deposit-feeding traces of the Planolites ichnoguild caused major disruption of lacustrine sedimentary fabrics during the Cretaceous. Most insect mouthpart classes, functional feeding groups, and dietary guilds were established by the end of the Cretaceous. Diversification of modern insects is recorded by the abundance and complexity of structures produced by wasps, bees, dung-beetles, and termites in Cretaceous-Tertiary paleosols. The increase in bioturbation migrated from fluvial and lake-margin settings to permanent subaqueous lacustrine environments through time.

Palaios↗