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

H umans have long been fascinated by the dynamism of free-flowing waters. Yet we have expended great effort to tame rivers for transportation, water supply, flood control, agriculture, and power generation. It is now recognized that harnessing of streams and rivers comes at great cost: Many rivers no longer support socially valued native species or sustain healthy ecosystems that provide important goods and services (Naiman et al. 1995, NRC 1992).

/pdf/the-natural-flow-regime-3j2upj9j41.pdf

The Natural Flow Regime

The flow regime is regarded by many aquatic ecologists to be the key driver of river and floodplain wet- land ecosystems. We have focused this literature review around four key principles to highlight the important mech- anisms that link hydrology and aquatic biodiversity and to illustrate the consequent impacts of altered flow regimes: Firstly, flow is a major determinant of physical habitat in streams, which in turn is a major determinant of biotic com- position; Secondly, aquatic species have evolved life history strategies primarily in direct response to the natural flow regimes; Thirdly, maintenance of natural patterns of longitu- dinal and lateral connectivity is essential to the viability of populations of many riverine species; Finally, the invasion and success of exotic and introduced species in rivers is facilitated by the alteration of flow regimes. The impacts of flow change are manifest across broad taxonomic groups including riverine plants, invertebrates, and fish. Despite growing recognition of these relationships, ecologists still struggle to predict and quantify biotic responses to altered flow regimes. One obvious difficulty is the ability to distin- guish the direct effects of modified flow regimes from im- pacts associated with land-use change that often accom- panies water resource development. Currently, evidence about how rivers function in relation to flow regime and the flows that aquatic organisms need exists largely as a series of untested hypotheses. To overcome these problems, aquatic science needs to move quickly into a manipulative or experimental phase, preferably with the aims of restora- tion and measuring ecosystem response.

/pdf/basic-principles-and-ecological-consequences-of-altered-flow-4u5bupofua.pdf

Basic principles and ecological consequences of altered flow regimes for aquatic biodiversity.

Classification of streams and stream habitats is useful for research involving establishment of monitoring stations, determination of local impacts of land-use practices, generalization from site-specific data, and assessment of basin-wide, cumulative impacts of human activities on streams and their biota. This article presents a frame-work for a hierarchical classification system, entailing an organized view of spatial and temporal variation among and within stream systems. Stream habitat systems, defined and classified on several spatiotemporal scales, are associated with watershed geomorphic features and events. Variables selected for classification define relative long-term capacities of systems, not simply short-term states. Streams and their watershed environments are classified within the context of a regional biogeoclimatic landscape classification. The framework is a perspective that should allow more systematic interpretation and description of watershed-stream relationships.

https://faculty.washington.edu/cet6/pub/Temp/CFR521e/Frissell_etal_1986.pdf

A hierarchical framework for stream habitat classification: Viewing streams in a watershed context

Food webs in nature have multiple, reticulate connections between a diversity of consumers and resources. Such complexity affects web dynamics: it first spreads the direct effects of consumption and productivity throughout the web rather than focusing them at particular "trophic levels." Second, consumer densities are often donor controlled with food from across the trophic spectrum, the herbivore and detrital channels, other habitats, life-history omnivory, and even trophic mutualism. Although consumers usually do not affect these resources, increased numbers often allow consumers to depress other resources to levels lower than if donor-controlled resources were absent. We propose that such donor-controlled and "multichannel" omnivory is a general feature of consumer control and central to food web dynamics. This observation is contrary to the normal practice of inferring dynamics by simplifying webs into a few linear "trophic levels," as per "green world" theories. Such theories do not accommodate commo...

Food Web Complexity and Community Dynamics

A state-space model for the microbial and abiotic decomposition of detritus in a temperate zone woodland stream is developed. Detritus, defined as nonliving, particulate organic matter and its associated microbial populations, is classified according to particle size and extent of microbial colonization as reflected by community respiration. These categories form a matrix whose entries are detrital biomass; detritus processing in the stream is simulated using transition functions to move biomass through the categories. The model can be coupled to population models of stream invertebrates via removal of detritus from the matrix for detritivore feeding. Simulation results are presented and compared with field data.

https://www.jstor.org/stable/info/1935306

Toward a model of detritus processing in a

A state—space model for the microbial and abiotic decomposition of detritus in a temperate zone woodland stream is developed. Detritus, defined as nonliving, particulate organic matter and its associated microbial populations, is classified according to particle size and extent of microbial colonization as reflected by community respiration. These categories form a matrix whose entries are detrital biomass; detritus processing in the stream is simulated using transition functions to move biomass through the categories. The model can be coupled to population models of stream invertebrates via removal of detritus from the matrix for detritivore feeding. Simulation results are presented and compared with field data. See full-text article at JSTOR

Toward A Model of Detritus Processing in a Woodland Stream

The breakdown of allochthonous leaf litter in woodland streams occurs at the community level process which is patchily distributed. Two kinds of environmental patches were tested: types of bottom sediment and sizes of leaf pack. Four sediments, aligned along parallel environmental gradients (velocity and sediment complexity), were studied: rock, gravel, sand, and silt. Five pack sizes were studied: 1, 5, 10, 20, and 40 g. Preweighed packs of white ash (Fraxinus americana) leaflets were tied to bricks and set on the sediments. These were sampled weekly for 6 wk, and the percent dry weight lost was determined. This design was followed in each of the four seasons to test the seasonal variability in leaf litter breakdown. Analysis of variance and comparison of means show that, in all seasons, sediment and pack—size effects are highly significant (P < .001). Leaf packs of all sizes were broken down less in the silt than in the other sediments. The sediment patterns are consistent with the community level effects of physical heterogeneity and stability. Though the pack—size effects were highly variable from season to season, the degree of breakdown differentiated the leaf—pack sizes in every season, at least one size displaying major differences from the others. The seasonal patterns in breakdown reflect its temperature dependence, the breakdown increasing with increasing temperature. The community level process of leaf litter breakdown in streams is patchily distributed in space. This suggests a level of organization between the population and the community, namely the patch—specific component community.

Environmental patchiness and the breakdown of leaf litter in a woodland stream

To test the roles of coarse particulate organic matter (CPOM) loading and fish predation on benthic community structure and leafpack breakdown, CPOM and fish density were manipulated in a stream. Mt. Sinai Creek, a 3rd-order stream in Piedmont North Carolina, USA, was divided into twelve 30-m 2 segments with 0.5-m high weirs. CPOM was loaded and maintained at 0.01 ambient, ambient and 4 × ambient levels for 19 mo. Fish were excluded from half the segments and maintained at natural densities in the others, in a fully cross-classified design. Neither CPOM loading nor fish predation had significant effects on leafpack breakdown and macrobenthic species richness or diversity in leafpack and sediment samples on all dates. The total abundance of invertebrates was reduced by fish in sediment samples but not in leafpacks. Almost all species were not significantly affected by the CPOM or fish treatments. Only two taxa responded to each treatment in sediments throughout the study, and none responded in le...

Seth R. Reice

Papers

Toward a model of detritus processing in a

Toward A Model of Detritus Processing in a Woodland Stream

Environmental patchiness and the breakdown of leaf litter in a woodland stream

Effects of Detritus Loading and Fish Predation on Leafpack Breakdown and Benthic Macroinvertebrates in a Woodland Stream

Comparative leaf litter decomposition in temporary and permanent streams in semi-arid regions of Israel