Treesearch

With the aim of acquiring a better understanding of ecological growth and biomass allocation of Neotropical trees, I inoculated Inga vera Willd. (Leguminosae) plants from cuttings with Rhizobium spp. and arbuscular mycorrhizal fungi and grew them in a greenhouse for 8 months under varying light (L), phosphorus (P), and nitrogen (N) treatments. I obtained the following results: (1) L, P × N, and L × P × N treatments affected every response variable, but most increases occurred under full light; that is, light levels influenced growth of Inga vera to a greater extent than did P and N...

We combine mist-net data from 24 disturbance treatments taken from seven studies on the responses of understorey Amazonian birds to selective logging, single and recurrent wildfires, and habitat fragmentation. The different disturbance treatments had distinct effects on avian guild structure, and fire disturbance and the isolation of forest patches resulted in bird communities that were most divergent from those in continuous, undisturbed forest in terms of their species composition. Although low-intensity logging treatments had the least noticeable effects, the composition of understorey...

We report the effects of an invasive tree (Syzygium jambos, Myrtaceace) on species composition, plant diversity patterns, and forest regeneration in primary and secondary forest in the Luquillo Mountains of northeastern Puerto Rico, including the area in and around the Caribbean National Forest (CNF) and the Luquillo Long Term Ecological Research site (Luquillo LTER). Land use history was reconstructed using aerial photographs from 1936 to 1989 and study sites were categorized into four groups that corresponded to their status in 1936: unforested, young secondary, mature secondary, and...

Part B The pearly-eyed thrasher is a major nest predator and competitor for nest sites of the endangered Puerto Rican Parrot. In all aspects of its distribution and ecology, Margarops fuscatus is a classic example of an avian “supertramp.” It is a pugnacious, highly vagile species, i.e., a good disperser, with a propensity to fill vacant or underexploited niches at all elevations by adopting generalized nesting and foraging strategies, as well as a varied diet. Having evolved superior colonizing traits at the expense of strong competitive characters, it is confined to about 80 generally...

Puerto Rico has gone through significant land cover change, going from an island that was forested to one that was agrarian and then finally becoming an urban island. Coastal wetlands experienced dramatic changes as alterations occurred in land cover and an eco-systematic analysis of these changes leads to the proposal of the following five ecological lessons learned from this experience: 1. Coastal landscapes are dynamic and continually changing due to changes in sea level, natural disturbance, and human activity. As a result, changes in cover and the condition of coastal ecosystems are...

The effects and implications of invasive species in belowground terrestrial ecosystems are not well known in comparison with aboveground terrestrial and marine environments. The study of earthworm invasions in the tropics is limited by a lack of taxonomic knowledge and the potential for loss of species in native habitats due to anthropogenic land use change. Alteration of land use plays a major role in determining the abundance and community structure of earthworms and the establishment of exotic earthworms in areas previously inhabited by worms. Once an exotic species has become establishe...

We predicted the spatial pattern of hourly probability of cloud cover in the Luquillo Experimental Forest (LEF) in North-Eastern Puerto Rico using four different models. The probability of cloud cover (defined as “the percentage of the area covered by clouds in each pixel on the map” in this paper) at any hour and any place is a function of three topographic variables: aspect, slope and the difference between elevation and lifting condensation level.We chose the best models based on multiple statistics including the Akaike Information Criterion (AIC), scaled deviance and extra-dispersion...

An overview of the phylogeny of the Agaricales is presented based on a multilocus analysis of a six-gene region supermatrix. Bayesian analyses of 5611 nucleotide characters of rpb1, rpb1-intron 2, rpb2 and 18S, 25S, and 5.8S ribosomal RNA genes recovered six major clades, which are recognized informally and labeled the Agaricoid, Tricholomatoid, Marasmioid, Pluteoid, Hygrophoroid and Plicaturopsidoid clades. Each clade is discussed in terms of key morphological and ecological traits. At least 11 origins of the ectomycorrhizal habit appear to have evolved in the Agaricales, with possibly as...

Land-use change, mainly forest burning, harvest, or clearing for agriculture, may compose 15 to 40 percent of annual human-caused emissions of carbon (C) to the atmosphere. Spatially extensive data on forest C pools can validate and parameterize atmospheric and ecosystem models of those fluxes and quantify fluxes from forest change. Excellent evidence exists that light detection and ranging (lidar) waveforms can be scaled to estimate forest biomass and aboveground C pools. The Geoscience Laser Altimeter Systmem (GLAS) instrument provides satellite-based continuous return lidar data and may...