0000000000416679
AUTHOR
W. Daniel Kissling
Spatial autocorrelation and the selection of simultaneous autoregressive models
Aim Spatial autocorrelation is a frequent phenomenon in ecological data and can affect estimates of model coefficients and inference from statistical models. Here, we test the performance of three different simultaneous autoregressive (SAR) model types (spatial error = SAR err , lagged = SAR lag and mixed = SAR mix ) and common ordinary least squares (OLS) regression when accounting for spatial autocorrelation in species distribution data using four artificial data sets with known (but different) spatial autocorrelation structures. Methods We evaluate the performance of SAR models by examining spatial patterns in model residuals (with correlograms and residual maps), by comparing model para…
Coefficient shifts in geographical ecology: an empirical evaluation of spatial and non-spatial regression
12 páginas, 4 figuras, 3 tablas.
Food plant diversity as broad-scale determinant of avian frugivore richness.
The causes of variation in animal species richness at large spatial scales are intensively debated. Here, we examine whether the diversity of food plants, contemporary climate and energy, or habitat heterogeneity determine species richness patterns of avian frugivores across sub-Saharan Africa. Path models indicate that species richness of Ficus (their fruits being one of the major food resources for frugivores in the tropics) has the strongest direct effect on richness of avian frugivores, whereas the influences of variables related to water–energy and habitat heterogeneity are mainly indirect. The importance of Ficus richness for richness of avian frugivores diminishes with decreasing sp…
Spatial patterns of woody plant and bird diversity: functional relationships or environmental effects?
Aim To understand cross-taxon spatial congruence patterns of bird and woody plant species richness. In particular, to test the relative roles of functional relationships between birds and woody plants, and the direct and indirect environmental effects on broad-scale species richness of both groups. Location Kenya. Methods Based on comprehensive range maps of all birds and woody plants (native species > 2.5 m in height) in Kenya, we mapped species richness of both groups. We distinguished species richness of four different avian frugivore guilds (obligate, partial, opportunistic and non-frugivores) and fleshy-fruited and non-fleshy-fruited woody plants. We used structural equation modelli…
Invasion ecology of the alien tussock grassNardus stricta(Poaceae) at Lake Pukaki, Canterbury, New Zealand
Abstract The European matgrass Nardus stricta has naturalised in New Zealand, often on damp soils within wetlands and grasslands. In this paper, we present for the first time field data on the ecology of this alien invader in New Zealand, from eight kettle‐hole wetlands on lateral moraine along the western side of Lake Pukaki, South Canterbury. The invaded wetland sites were all acidic but varied in other soil characteristics. Nardus stricta was the most dominant species within these wetland communities with 40% of all plots showing more than 50% coverage, and 21% having more than 90% cover. Species richness (including vascular plants and mosses) at some sites was relatively high (c. 40 spe…
The global distribution of frugivory in birds
Aim To examine patterns of avian frugivory across clades, geography and environments. Location Global, including all six major biogeographical realms (Afrotropics, Australasia, Indo-Malaya, Nearctic, Neotropics and Palaearctic). Methods First, we examine the taxonomic distribution of avian frugivory within orders and families. Second we evaluate, with traditional and spatial regression approaches, the geographical patterns of frugivore species richness and proportion. Third, we test the potential of contemporary climate (water–energy, productivity, seasonality), habitat heterogeneity (topography, habitat diversity) and biogeographical history (captured by realm membership) to explain geo…