Treesearch

Tropical secondary forests provide many products, environmental services, and recreation. These forests have a set of biological features, such as their high productivity and a uniform composition of dominant tree species. To understand the composition and structure of a secondary forest in the northern karst zone, we selected the Santa Ana Environmental Center (CASA by its Spanish acronym), Bayamón, Puerto Rico, in the San Juan metropolitan area. It lies within the subtropical moist forest zone according to the Holdridge classification system (Ewel and Whitmore 1973). The objective of...

An analysis of genetic structure and differentiation in cultivated walnut (Juglans regia) using 15 microsatellite loci revealed a considerable amount of genetic variation with a mild genetic structure indicating five genetic groups corresponding to the centers of diversity within the home range of walnut in Eurasia. Despite the narrow genetic differentiation among groups accounting for only 10 to 15% of the total variation, the groups differed significantly with respect to frequency and composition of alleles for different loci. Moderate to high genetic variability with mild genetic...

Many songbird species have experienced significant population declines, partly because of brood parasitism by the Brown-headed Cowbird (Molothrus ater), which is positively associated with increasing landscape forest cover in the midwestern United States. However, cowbirds are also experiencing long-term population declines, which should reduce parasitism pressure and thus increase productivity of host species. We used 20 years of nest monitoring data from five sites in Missouri across a gradient of landscape forest cover to assess temporal trends in the rate and intensity of brood...

Alterations in variance of riverine thermal regimes have been observed and are predicted with climate change and human development. We tested whether changes in daily or seasonal thermal variability, aside from changes in mean temperature, could have biological consequences by exposing Chinook salmon (Oncorhynchus tshawytscha) eggs to eight experimental thermal regimes. Thermal variance impacted both emergence timing and development at emergence. Further, genetics influenced the magnitude of that response. Ecological implications include: (1) changes in thermal variability, independent of...

Forest ecosystems are the most important terrestrial carbon (C) storage globally, and presently mitigate anthropogenic climate change by acting as a large and persistent sink for atmospheric CO2. Yet, forest C density varies greatly in space, both globally and at stand and landscape levels. Understanding the multi-scale drivers of this variation is a prerequisite for robust and effective climate change mitigation in ecosystem management. Here, we used airborne light detection and ranging (Lidar) and a novel high-resolution simulation model of landscape dynamics (iLand) to identify the...

Inexpensive remote temperature data loggers have allowed for a dramatic increase of data describing water temperature regimes. This data is used in understanding the ecological functioning of natural riverine systems and in quantifying changes in these systems. However, an increase in the quantity of yearly temperature data necessitates complex data management, efficient summarization, and an effective data-cleaning regimen. This note focuses on identifying events where data loggers failed to record correct temperatures using data from the Sauk River in Northwest Washington State as an...

The relationship between number of species and area observed has been described using numerous approaches and has been discussed for more than a century. The general objectives of our study were fourfold: (1) to evaluate the behaviour of species-area curves across geographic scales, (2) to determine sample sizes necessary to produce acceptably precise estimates of tree species diversity, (3) to evaluate relationships among estimates of tree species diversity for local to large geographic scales, and (4) to determine whether the proportion of native tree species may be precisely estimated...

Tree diameter and height are commonly measured forest structural variables, and indicators based on them are candidates for assessing forest diversity. We conducted our study on the uncertainty of estimates for mostly large geographic scales for four indicators of forest structural gamma diversity: mean tree diameter, mean tree height, and standard deviations of tree diameter and tree height. We had three objectives: to estimate the number of national forest inventory (NFI) plots whose data must be aggregated to obtain precise estimates of the indicators of gamma forest structural diversity...