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Much of western North America is dominated by dense, monotypic, late seral stands of big sagebrush (Artemisia tridentata Nutt.). These stands often have depauperate understories with limited species richness, diversity, and herbaceous cover. The National Park Service at Dinosaur National Monument, Colorado, is using both strategic and natural prescribed fire in Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis Beetle and Young) communi- ties to foster intra-community (α-scale) and landscape diversity. This study analyzed an accumulated foliar cover data set between paired burn and control areas on 6 different sites during the last 20 years. Across the monitoring period, mean total vegetation cover of...
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Effects of annual additions of mineral N and P (100 kg ha-1) on plant species composition and annual aboveground net primary production (ANPP) were investigated during the first three years following disturbance in a semi-arid ecosystem. Additions of N reduced richness of perennial plant species during years 2 and 3, while P reduced the number of perennial species only in year 3. From year 1 to year 2, annual and biennial species richness declined in all treatments while ANPP of annual species increased greatly. Added N increased ANPP of annual species while it decreased ANPP of most perennial species relative to the unfertilized control treatment. Community similarities were higher for the control and native vegetation...
The Odonata fauna of the Grand Canyon ecoregion (GCE) on the southern Colorado Plateau includes 89 species (35 genera, seven families), including 49 Anisoptera species (25 genera, four families) and 40 Zygoptera species (10 genera, three families), and with 58 Odonata species in Grand Canyon (GC; 24 genera, seven families). Three biogeographic hypotheses account for this relatively high regional species richness: faunal affinity (origin), elevation effects on range, and landform impacts across spatial scale. The GCE Odonata assemblage is the result of mixing of taxa from adjacent Neotropical and Nearctic regions. Allochthonous taxa include 34.8% tropical (Mexican, Caribbean, Neotropical, or Pantropical) and 21.3%...
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Conclusions: Frogs and toad species were more abundant and diverse where habitat patch diversity was high or where there were forested wetland edges. Relative abundances of amphibian populations correlated positively with metrics such as the length of edge between forest and wetland, and negatively with the presence of agricultural and urban land. Thresholds/Learnings: Synopsis: This study examined landscape-level relationships for frogs and toads by measuring associations between relative abundance and species richness based on survey data derived from anuran calls and features of land cover maps for Iowa and Wisconsin. Relative abundances correlated positively with metrics such as the length of edge between forest...
Nitrogen (N) and phosphorus (P) availability limit plant growth in most terrestrial ecosystems. This review examines how variation in the relative availability of N and P, as reflected by N : P ratios of plant biomass, influences vegetation composition and functioning. Plastic responses of plants to N and P supply cause up to 50-fold variation in biomass N : P ratios, associated with differences in root allocation, nutrient uptake, biomass turnover and reproductive output. Optimal N : P ratios ? those of plants whose growth is equally limited by N and P ? depend on species, growth rate, plant age and plant parts. At vegetation level, N : P ratios <10 and >20 often (not always) correspond to N- and P-limited biomass...
There has been uncertainty in the national gap analysis program about including non-breeding birds in distribution models because of concerns that distributions of migrant and winter birds are difficult to predict and are not necessary to assess biodiversity patterns. New Mexico gap analysis included migrant and non-breeding birds assuming that distributions could be predicted using habitat associations, and that excluding non-breeding bird habitat from avian richness projections potentially underestimates community types important to birds. We compared biodiversity estimates including non-breeding birds (inclusive estimate - 324 species) to estimates including only breeding birds (breeding bird estimate - 257 species)...
Summary (from http://onlinelibrary.wiley.com/doi/10.1111/fwb.12807/abstract) Conservation of freshwater unionid mussels presents unique challenges due to their distinctive life cycle, cryptic occurrence and imperilled status. Relevant ecological information is urgently needed to guide their management and conservation. We adopted a modelling approach, which is a novel application to freshwater mussels to enhance inference on rare species, by borrowing data among species in a hierarchical framework to conduct the most comprehensive occurrence analysis for freshwater mussels to date. We incorporated imperfect detection to more accurately examine effects of biotic and abiotic factors at multiple scales on the occurrence...
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Shrub encroachment due to overgrazing has led to dramatic changes of savanna landscapes and is considered to be one of the most threatening forms of rangeland degradation e.g. via habitat fragmentation. Mammalian carnivores are particularly vulnerable to local extinction in fragmented landscapes. However, our understanding of how shrub encroachment affects mammalian carnivores is poor. Here we investigated the relative sensitivities of ten native carnivores to different levels of shrub cover ranging from low (<5%) to high shrub cover (>25%) in 20 southern Kalahari rangeland sites. Relative abundance of carnivores was monitored along 40 sand transects (5 m × 250 m) for each site. Our results show that increasing...
We attempted a complete review of the empirical literature on effects of roads and traffic on animal abundance and distribution. We found 79 studies, with results for 131 species and 30 species groups. Overall, the number of documented negative effects of roads on animal abundance outnumbered the number of positive effects by a factor of 5; 114 responses were negative, 22 were positive, and 56 showed no effect. Amphibians and reptiles tended to show negative effects. Birds showed mainly negative or no effects, with a few positive effects for some small birds and for vultures. Small mammals generally showed either positive effects or no effect, mid-sized mammals showed either negative effects or no effect, and large...
Conclusions:Over time, native species richness increased slightly, but dropped dramatically after several years of burning. Year-to-year change in community composition was found to be affected by time since fire and fluctuations in growing season temperature and rainfall. Examining successional trajectory showed that the restoration has been most successful at reducing exotic species and increasing species heterogeneity, but has largely failed to increase native species richness at the level of remnant prairies, largely due to interspecies resource competition.Thresholds/Learnings:
Arthropods living in the canopies of two woody shrub species (a sub-shrub (Gutierrezia sarothrae) and a large shrub (Prosopis glandulosa)) and perennial grasses plus associated herbaceous species, were sampled on 18, 0.5 hectare plots in a Chihuahuan Desert grassland for five consecutive years. Mesquite shrubs were removed from nine plots, six plots were grazed by yearling cattle in August and six plots were grazed in February for the last 3 years of the 5 year study. Arthropod species richness ranged between 154 and 353 on grasses, from 120 to 266 on G. sarothrae, and from 69 to 116 on P. glandulosa. There was a significant relationship between the number of families of insects on grass and G. sarothrae and growing...
Increasing demands on arid and semiarid ecosystems, which comprise one-third of Earth's terrestrial environment, create an urgent need to understand their biodiversity, function, and mechanisms of change. Sagebrush (Artemisia) steppe, the largest semiarid vegetation type in North America, is endangered because of losses to agriculture, excessive grazing, and invasive species. Establishment in 1950 of what is now designated as the Idaho National Engineering and Environmental Laboratory (southeastern Idaho, USA) created the largest existing reserve of this extensive vegetation type. We used cover, density, and frequency data for vascular plants sampled on 79 permanent plots nine times during 45 years to (1) assess...
We studied the associations of crayfish with reach-scale instream habitat and water quality variables and watershed-scale variables of riparian and watershed land cover, runoff, impervious surfaces, and hydrologic soil type in west-central Indiana. Crayfish assemblage was measured by abundance, species richness, and diversity (Shannon's H) at 180 sites. The western portion of the study area, within the Interior River Lowland ecoregion, has been heavily impacted by agriculture, while the eastern portion, within the Interior Plateau ecoregion, is more heavily wooded and less impacted. The ability of variables at each spatial extent to predict crayfish assemblage was assessed using multiple linear regression analysis....
Categories: Publication; Types: Citation; Tags: ASFA 1: Biological Sciences & Living Resources, Abundance, Agricultural development, Agriculture, Biology--Entomology, All tags...
Geospatial statistical modelling and thematic maps have recently emerged as effective tools for the management of natural areas at the landscape scale. Traditional methods for the collection of field data pertaining to questions of landscape were developed without consideration for the parameters of these applications. We introduce an alternative field sampling design based on smaller unbiased random plot and subplot locations called the pixel nested plot (PNP). We demonstrate the applicability of the PNP design of 15 m � 15 m to assess patterns of plant diversity and species richness across the landscape at Rocky Mountain National Park (RMNP), Colorado, USA in a time (cost)-efficient manner for field data collection....
Conclusions:Results indicate that breeding bird species richness patterns significantly increased with fragment size. Area-sensitive species required patches of suitable habitat at least 5-55 ha in size. Edge and vegetation-restricted species were more affected by overall habitat loss of habitat than reductions in average patch size.Thresholds/Learnings:Area-sensitive species required patches of suitable habitat at least 5-55 ha in size, and regularly avoided smaller grassland fragments even when they were composed of suitable habitat
We attempted a complete review of the empirical literature on effects of roads and traffic on animal abundance and distribution. We found 79 studies, with results for 131 species and 30 species groups. Overall, the number of documented negative effects of roads on animal abundance outnumbered the number of positive effects by a factor of 5; 114 responses were negative, 22 were positive, and 56 showed no effect. Amphibians and reptiles tended to show negative effects. Birds showed mainly negative or no effects, with a few positive effects for some small birds and for vultures. Small mammals generally showed either positive effects or no effect, mid-sized mammals showed either negative effects or no effect, and large...
The rank-abundance distribution (RAD) represents the manner in which species divide resources. Community-specific division rules that determine resource allocation among species, and thereby the shape of the RAD, have been hypothesized to account for observed stability of local species richness over time. While the shape of the RAD has been well studied, the temporal dynamics of this distribution have received much less attention. Here we assess changes in the shape of the RAD through time in a desert rodent community in Arizona (USA). Because energy use may be more appropriate for studying resource division than abundance, we also evaluate an energetic equivalent of the RAD. Significant, directional trends in the...
Conclusions:Patch area was shown to be an important determinant of species richness irrespective of habitat heterogeneity. Isolation in space was also a significant factors in determining the degree of species richness in a grassland landscape.Thresholds/Learnings:
    map background search result map search result map Vegetation response to prescribed fire in Dinosaur National Monument Plant community dynamics in a semi-arid ecosystem in relation to nutrient addition following a major disturbance Shrub encroachment affects mammalian carnivore abundance and species richness in semiarid rangelands Effects of landscape composition and wetland fragmentation on frog and toad abundance and species richness in Iowa and Wisconsin, USA. Vegetation response to prescribed fire in Dinosaur National Monument Plant community dynamics in a semi-arid ecosystem in relation to nutrient addition following a major disturbance Effects of landscape composition and wetland fragmentation on frog and toad abundance and species richness in Iowa and Wisconsin, USA. Shrub encroachment affects mammalian carnivore abundance and species richness in semiarid rangelands