Elisabeth K. V. Kalko

Bio: Elisabeth K. V. Kalko is an academic researcher from University of Ulm. The author has contributed to research in topics: Human echolocation & Frugivore. The author has an hindex of 59, co-authored 171 publications receiving 11511 citations. Previous affiliations of Elisabeth K. V. Kalko include Smithsonian Tropical Research Institute.

Averting biodiversity collapse in tropical forest protected areas

Abstract: The rapid disruption of tropical forests probably imperils global biodiversity more than any other contemporary phenomenon(1-3). With deforestation advancing quickly, protected areas are increasingly becoming final refuges for threatened species and natural ecosystem processes. However, many protected areas in the tropics are themselves vulnerable to human encroachment and other environmental stresses(4-9). As pressures mount, it is vital to know whether existing reserves can sustain their biodiversity. A critical constraint in addressing this question has been that data describing a broad array of biodiversity groups have been unavailable for a sufficiently large and representative sample of reserves. Here we present a uniquely comprehensive data set on changes over the past 20 to 30 years in 31 functional groups of species and 21 potential drivers of environmental change, for 60 protected areas stratified across the world's major tropical regions. Our analysis reveals great variation in reserve 'health': about half of all reserves have been effective or performed passably, but the rest are experiencing an erosion of biodiversity that is often alarmingly widespread taxonomically and functionally. Habitat disruption, hunting and forest-product exploitation were the strongest predictors of declining reserve health. Crucially, environmental changes immediately outside reserves seemed nearly as important as those inside in determining their ecological fate, with changes inside reserves strongly mirroring those occurring around them. These findings suggest that tropical protected areas are often intimately linked ecologically to their surrounding habitats, and that a failure to stem broad-scale loss and degradation of such habitats could sharply increase the likelihood of serious biodiversity declines.

Echolocation by insect-eating bats

Abstract: B (order Chiroptera) are ecologically more diverse than any other group of mammals. Numerous morphological, physiological, and behavioral adaptations of sensory and motor systems permit bats access to a wide range of habitats and resources at night. The more than 750 species of the suborder Microchiroptera occupy most terrestrial habitats and climatic zones and exploit a great variety of foods, ranging from insects and other arthropods, small vertebrates, and blood to fruit, leaves, nectar, flowers, and pollen. Echolocation is one of the adaptations that make bats so successful. Echolocating animals emit signals of high frequency (mostly ultrasonic) and analyze the returning echoes to detect, characterize, and localize the reflected objects. Sophisticated echolocation systems have evolved only in the bat suborder Microchiroptera and in dolphins. Less efficient systems have been reported for a few species of the bat suborder Megachiroptera and for some birds (Henson and Schnitzler 1980). Bats use echolocation for orientation in space, that is, for determining their position relative to the echo-producing environment. In addition, many bats, especially those that hunt for flying insects, use echolocation to detect, identify, and localize prey. Bats use a wide variety of species-specific signal types differing in frequency structure, duration, and sound pressure level (SPL). In addition, signal structure varies depending on the echolocation task confronting the bat. Search signals that are emitted when bats search for prey differ from approach signals that are emitted when they approach prey. The echolocation signals and hearing systems of bats are well adapted for gathering behaviorally relevant information (e.g., Schnitzler and Henson 1980, Neuweiler 1989, Fenton 1990, Denzinger et al. forthcoming). In this article we describe the echolocation behavior of insect-eating bats and show how differing circumstances such as habitat type, foraging mode, and diet favor different signal types. To demonstrate relationships between echolocation and ecological conditions, we outline the perceptual tasks that must be performed by foraging bats and discuss the suitability of typical elements of echolocation signals for solving such problems. We then define habitat types according to the problems they impose on bats and relate the observed variability in signal structure to ecological constraints set by habitat type and foraging mode. Perceptual problems for foraging bats Foraging bats confront a multitude of problems when flying to their hunting grounds and searching for prey. These problems differ depending on where bats hunt, what they eat, and how they acquire their food. For example, bats hunting for insects in the open encounter conditions different from those that search for prey near the edges of vegetation, in vegetation gaps, in dense forest, or near the ground. The problems also differ depending upon whether they capture moving prey in flight (aerial mode) or mostly stationary prey from surfaces such as leaves or ground (gleaning mode) or water (trawling mode). Foraging bats must detect, classify, and localize an insect and discriminate between echoes of prey and echoes of unwanted targets such as twigs, foliage, or the ground, referred to as clutter echoes, or simply “clutter.”For many bats echolocation delivers all of the information they need to catch an insect.

Corrigendum: Bats host major mammalian paramyxoviruses.

Abstract: Nature Communications 3: Article number: 796 (2012); Published: 24 April 2012; Updated: 23 January 2014. The authors inadvertently omitted Veronika M. Cottontail and Mirjam Knornschild, who collected samples in Panama and Costa Rica, from the author list. This has now been corrected in both the PDF and HTML versions of the Article.

Citation classic - optimal foraging - a selective review of theory and tests

Abstract: Beginning with Emlen (1966) and MacArthur and Pianka (1966) and extending through the last ten years, several authors have sought to predict the foraging behavior of animals by means of mathematical models. These models are very similar,in that they all assume that the fitness of a foraging animal is a function of the efficiency of foraging measured in terms of some "currency" (Schoener, 1971) -usually energy- and that natural selection has resulted in animals that forage so as to maximize this fitness. As a result of these similarities, the models have become known as "optimal foraging models"; and the theory that embodies them, "optimal foraging theory." The situations to which optimal foraging theory has been applied, with the exception of a few recent studies, can be divided into the following four categories: (1) choice by an animal of which food types to eat (i.e., optimal diet); (2) choice of which patch type to feed in (i.e., optimal patch choice); (3) optimal allocation of time to different patches; and (4) optimal patterns and speed of movements. In this review we discuss each of these categories separately, dealing with both the theoretical developments and the data that permit tests of the predictions. The review is selective in the sense that we emphasize studies that either develop testable predictions or that attempt to test predictions in a precise quantitative manner. We also discuss what we see to be some of the future developments in the area of optimal foraging theory and how this theory can be related to other areas of biology. Our general conclusion is that the simple models so far formulated are supported are supported reasonably well by available data and that we are optimistic about the value both now and in the future of optimal foraging theory. We argue, however, that these simple models will requre much modification, espicially to deal with situations that either cannot easily be put into one or another of the above four categories or entail currencies more complicated that just energy.

Global effects of land use on local terrestrial biodiversity

Abstract: Human activities, especially conversion and degradation of habitats, are causing global biodiversity declines. How local ecological assemblages are responding is less clear--a concern given their importance for many ecosystem functions and services. We analysed a terrestrial assemblage database of unprecedented geographic and taxonomic coverage to quantify local biodiversity responses to land use and related changes. Here we show that in the worst-affected habitats, these pressures reduce within-sample species richness by an average of 76.5%, total abundance by 39.5% and rarefaction-based richness by 40.3%. We estimate that, globally, these pressures have already slightly reduced average within-sample richness (by 13.6%), total abundance (10.7%) and rarefaction-based richness (8.1%), with changes showing marked spatial variation. Rapid further losses are predicted under a business-as-usual land-use scenario; within-sample richness is projected to fall by a further 3.4% globally by 2100, with losses concentrated in biodiverse but economically poor countries. Strong mitigation can deliver much more positive biodiversity changes (up to a 1.9% average increase) that are less strongly related to countries' socioeconomic status.

Habitat fragmentation and its lasting impact on Earth’s ecosystems

Abstract: We conducted an analysis of global forest cover to reveal that 70% of remaining forest is within 1 km of the forest’s edge, subject to the degrading effects of fragmentation. A synthesis of fragmentation experiments spanning multiple biomes and scales, five continents, and 35 year sd emonstrates that habitatfragmentation reduces biodiversity by 13 to 75% and impairs key ecosystem functions by decreasing biomass and altering nutrient cycles. Effects are greatest in the smallest and most isolated fragments, and they magnify with the passage of time. These findings indicate an urgent need for conservation and restoration measures to improve landscape connectivity, which will reduce extinction rates and help maintain ecosystem services.

Supplementary Materials for Habitat fragmentation and its lasting impact on Earth's ecosystems

Abstract: Urgent need for conservation and restoration measures to improve landscape connectivity. We conducted an analysis of global forest cover to reveal that 70% of remaining forest is within 1 km of the forest’s edge, subject to the degrading effects of fragmentation. A synthesis of fragmentation experiments spanning multiple biomes and scales, five continents, and 35 years demonstrates that habitat fragmentation reduces biodiversity by 13 to 75% and impairs key ecosystem functions by decreasing biomass and altering nutrient cycles. Effects are greatest in the smallest and most isolated fragments, and they magnify with the passage of time. These findings indicate an urgent need for conservation and restoration measures to improve landscape connectivity, which will reduce extinction rates and help maintain ecosystem services.

The performance and potential of protected areas

Abstract: Originally conceived to conserve iconic landscapes and wildlife, protected areas are now expected to achieve an increasingly diverse set of conservation, social and economic objectives. The amount of land and sea designated as formally protected has markedly increased over the past century, but there is still a major shortfall in political commitments to enhance the coverage and effectiveness of protected areas. Financial support for protected areas is dwarfed by the benefits that they provide, but these returns depend on effective management. A step change involving increased recognition, funding, planning and enforcement is urgently needed if protected areas are going to fulfil their potential.