Preface to the Princeton Landmarks in Biology Edition vii Preface xi Symbols Used xiii 1. The Importance of Islands 3 2. Area and Number of Speicies 8 3. Further Explanations of the Area-Diversity Pattern 19 4. The Strategy of Colonization 68 5. Invasibility and the Variable Niche 94 6. Stepping Stones and Biotic Exchange 123 7. Evolutionary Changes Following Colonization 145 8. Prospect 181 Glossary 185 References 193 Index 201

The Theory of Island Biogeography

A huge road network with vehicles ramifies across the land, representing a surprising frontier of ecology. Species-rich roadsides are conduits for few species. Roadkills are a premier mortality source, yet except for local spots, rates rarely limit population size. Road avoidance, especially due to traffic noise, has a greater ecological impact. The still-more-important barrier effect subdivides populations, with demographic and probably genetic consequences. Road networks crossing landscapes cause local hydrologic and erosion effects, whereas stream networks and distant valleys receive major peak-flow and sediment impacts. Chemical effects mainly occur near roads. Road networks interrupt horizontal ecological flows, alter landscape spatial pattern, and therefore inhibit important interior species. Thus, road density and network structure are informative landscape ecology assays. Australia has huge road-reserve networks of native vegetation, whereas the Dutch have tunnels and overpasses perforating road barriers to enhance ecological flows. Based on road-effect zones, an estimated 15‐20% of the United States is ecologically impacted by roads.

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Roads and their major ecological effects

Global declines in insects have sparked wide interest among scientists, politicians, and the general public. Loss of insect diversity and abundance is expected to provoke cascading effects on food webs and to jeopardize ecosystem services. Our understanding of the extent and underlying causes of this decline is based on the abundance of single species or taxonomic groups only, rather than changes in insect biomass which is more relevant for ecological functioning. Here, we used a standardized protocol to measure total insect biomass using Malaise traps, deployed over 27 years in 63 nature protection areas in Germany (96 unique location-year combinations) to infer on the status and trend of local entomofauna. Our analysis estimates a seasonal decline of 76%, and mid-summer decline of 82% in flying insect biomass over the 27 years of study. We show that this decline is apparent regardless of habitat type, while changes in weather, land use, and habitat characteristics cannot explain this overall decline. This yet unrecognized loss of insect biomass must be taken into account in evaluating declines in abundance of species depending on insects as a food source, and ecosystem functioning in the European landscape.

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More than 75 percent decline over 27 years in total flying insect biomass in protected areas.

Worldwide decline of the entomofauna: A review of its drivers

Climate change is predicted to become a major threat to biodiversity in the 21st century, but accurate predictions and effective solutions have proved difficult to formulate. Alarming predictions have come from a rather narrow methodological base, but a new, integrated science of climate-change biodiversity assessment is emerging, based on multiple sources and approaches. Drawing on evidence from paleoecological observations, recent phenological and microevolutionary responses, experiments, and computational models, we review the insights that different approaches bring to anticipating and managing the biodiversity consequences of climate change, including the extent of species' natural resilience. We introduce a framework that uses information from different sources to identify vulnerability and to support the design of conservation responses. Although much of the information reviewed is on species, our framework and conclusions are also applicable to ecosystems, habitats, ecological communities, and genetic diversity, whether terrestrial, marine, or fresh water.

Beyond Predictions: Biodiversity Conservation in a Changing Climate

We studied dispersal of Great Reed Warblers Acrocephalus arundinaceus, using a mark—resight model for dispersal. We assessed the relevance of ecological distance, defined as movement along reed edges, as opposed to straight line distance for predicting the distribution of dispersal. In a mark—resight study in the northern Netherlands, 1158 birds were ringed. 178 birds were resighted at least once, with 254 movements between known nesting locations in successive years. Dispersal was defined as movement between successive nesting sites, and modelled as an exponential function of ecological and geographical distances. To correctly model dispersal probabilities in the fragmented study area, the model discriminates between suitable habitat sections and intermediate gaps. Several nested models for dispersal were compared by means of the likelihood ratio test. Models incorporating ecological distance gave a better fit than models using geographical distance, although the difference was not large. To describe dis...

https://bioone.org/journals/ardea/volume-98/issue-3/078.098.0312/Modelling-Small-Scale-Dispersal-of-the-Great-Reed-Warbler-Acrocephalus/10.5253/078.098.0312.pdf

Modelling small-scale dispersal of the Great Reed Warbler Acrocephalus arundinaceus in a fragmented landscape

Disturbance by traffic as a threat to breeding birds: evaluation of the effect and considerations in planning and managing road corridors

Ecological corridors on a European scale: a typology and identification of target species

The increased variability in weather as a manifestation of climate change is expected to have negative impacts on population survival in wildlife species, because it will likely lead to increased variation in vital demographic rates (mortality and reproduction) in these populations. For the effective protection of biodiversity, adaptation measures are needed to compensate for the expected increase in weather variability and the negative interaction with habitat fragmentation. As a case study, we studied the fluctuations in Great Bittern numbers (Botaurus stellaris) from 28 monitoring plots scattered over the Netherlands to explore the interaction between the effect of weather and possible remediating effects of the landscape structure. Great Bittern habitat surrounding these plots differs with respect to area, quality, and degree of isolation of this habitat. In western Europe, Great Bitterns are found to be susceptible to continuous loss of suitable habitat due to vegetation succession and fragmentation. Moreover, year-to-year fluctuations in local Great Bittern populations can be caused by severe winter weather or other weather extremes. Our results show that severe winter weather has indeed a significant negative impact on Great Bittern population growth rates. Furthermore, we found that an increased carrying capacity and spatial cohesion (i.e. inverse of habitat fragmentation) contribute to an increase in mean growth rates over the years. As growth rates are higher in large, well-connected habitats, we argue that recovery from negative effects of, e.g. severe winters on Great Bittern population numbers is enhanced in these less-fragmented habitats. We derived generic adaptation measures for enhancing the recovery rate of populations of species in general: one should invest in more large, well-connected nature areas, not only to diminish the negative effects of habitat fragmentation on wildlife populations, but additionally to reduce the impacts of climatic variability.

Ruud P. B. Foppen

Papers

Modelling small-scale dispersal of the Great Reed Warbler Acrocephalus arundinaceus in a fragmented landscape

Disturbance by traffic as a threat to breeding birds: evaluation of the effect and considerations in planning and managing road corridors

Ecological corridors on a European scale: a typology and identification of target species

Population dynamics of Great Bittern (Botaurus stellaris) in the Netherlands: interaction effects of winter weather and habitat fragmentation

Wetzel et al. fail to identify the real gaps in European bird monitoring