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

Freshwater biodiversity is the over-riding conservation priority during the International Decade for Action - 'Water for Life' - 2005 to 2015. Fresh water makes up only 0.01% of the World's water and approximately 0.8% of the Earth's surface, yet this tiny fraction of global water supports at least 100000 species out of approximately 1.8 million - almost 6% of all described species. Inland waters and freshwater biodiversity constitute a valuable natural resource, in economic, cultural, aesthetic, scientific and educational terms. Their conservation and management are critical to the interests of all humans, nations and governments. Yet this precious heritage is in crisis. Fresh waters are experiencing declines in biodiversity far greater than those in the most affected terrestrial ecosystems, and if trends in human demands for water remain unaltered and species losses continue at current rates, the opportunity to conserve much of the remaining biodiversity in fresh water will vanish before the 'Water for Life' decade ends in 2015. Why is this so, and what is being done about it? This article explores the special features of freshwater habitats and the biodiversity they support that makes them especially vulnerable to human activities. We document threats to global freshwater biodiversity under five headings: overexploitation; water pollution; flow modification; destruction or degradation of habitat; and invasion by exotic species. Their combined and interacting influences have resulted in population declines and range reduction of freshwater biodiversity worldwide. Conservation of biodiversity is complicated by the landscape position of rivers and wetlands as 'receivers' of land-use effluents, and the problems posed by endemism and thus non-substitutability. In addition, in many parts of the world, fresh water is subject to severe competition among multiple human stakeholders. Protection of freshwater biodiversity is perhaps the ultimate conservation challenge because it is influenced by the upstream drainage network, the surrounding land, the riparian zone, and - in the case of migrating aquatic fauna - downstream reaches. Such prerequisites are hardly ever met. Immediate action is needed where opportunities exist to set aside intact lake and river ecosystems within large protected areas. For most of the global land surface, trade-offs between conservation of freshwater biodiversity and human use of ecosystem goods and services are necessary. We advocate continuing attempts to check species loss but, in many situations, urge adoption of a compromise position of management for biodiversity conservation, ecosystem functioning and resilience, and human livelihoods in order to provide a viable long-term basis for freshwater conservation. Recognition of this need will require adoption of a new paradigm for biodiversity protection and freshwater ecosystem management - one that has been appropriately termed 'reconciliation ecology'.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/96AA265E3D88C95FB802E7A73CCB4332/S1464793105006950a.pdf/div-class-title-freshwater-biodiversity-importance-threats-status-and-conservation-challenges-div.pdf

Freshwater biodiversity: importance, threats, status and conservation challenges

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

▪ Abstract Local habitat and biological diversity of streams and rivers are strongly influenced by landform and land use within the surrounding valley at multiple scales. However, empirical associations between land use and stream response only varyingly succeed in implicating pathways of influence. This is the case for a number of reasons, including (a) covariation of anthropogenic and natural gradients in the landscape; (b) the existence of multiple, scale-dependent mechanisms; (c) nonlinear responses; and (d) the difficulties of separating present-day from historical influences. Further research is needed that examines responses to land use under different management strategies and that employs response variables that have greater diagnostic value than many of the aggregated measures in current use. In every respect, the valley rules the stream.      H.B.N. Hynes (1975)

http://deq.idaho.gov/media/525804-Landscapes_Riverscapes_Influence_landuse_stream_ecosystems_Allan_2004.pdf

Landscapes and Riverscapes: The Influence of Land Use on Stream Ecosystems

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.

Aquatic invertebrate community structure was quantified from six sites, each located in distinctly different geomorphic reaches along the Tagliamento River (N.E. Italy). Quantitative samples of benthic invertebrates were collected quarterly over one year from six sites (from 5- 1100m above sea level), while physico-chemical data were collected monthly. Total abundance of benthic invertebrates was highly vari- able in space and time with a minimum density of 433 ± 158 individuals m -2 (± 1 standard deviation; n = 3) occurring in the main channel of an island-braided flood plain midway along the continuum after the autumnal floods (November 1998). At most sites, maximum densities (111,226 ± 45,395ind.m -2 ) were observed during late summer (August 1998). In August, insects comprised more than 87% of all taxa in each reach, with Chironomidae (Diptera) and Baetidae (Ephemeroptera) being the most abundant insect families. Abundance of Insecta, Crustacea (primarily copepods and amphipods), Oligochaeta, Nematoda, and Hydrachnidia all increased with distance downstream. In general, dominant insect taxa were represented by highly mobile forms with potential for multivoltinism (Chironomidae, Baetidae, Simuliidae). Non-insect taxa were also well represented by high mobility (e.g., Echinogammarus spp.) and ability to rapidly reproduce (e.g., Oligochaeta, Nematoda, Copepoda), life-cycle strate- gies critical for persistence in a highly dynamic and physically harsh environment. Temperature, substrate size, nutrient concentrations, benthic organic matter, and bio- mass of epilithic algae all exhibited distinct changes along the continuum. Changes in benthic invertebrate community structure (abundance and diversity) also occurred along the longitudinal gradient and these changes were correlated with spatial and tem- poral shifts in various environmental factors. Longitudinal patterns revealed by Co- Inertia analysis, corroborated diversity and abundance patterns by illustrating the dis-

Spatio-temporal patterns of benthic invertebrates along the continuum of a braided Alpine river

The influence of increased fluoride concentrations generated by a wastewater treatment plant on the spatial distribution and abundance of benthic larvae of Hydropsychidae (Insecta, Trichoptera) species in the Cache la Poudre River (Colorado) was examined. Acute lethal concentrations of fluoride ion (F−) to these species were determined in soft water (average value of hardness 40.2 mg CaCO3/L) by static toxicity bioassays. The wastewater treatment plant caused a significant (P<0.05) increase in the fluoride concentration at three downstream sampling sites (mean values 1.17, 0.84, and 0.56 mg F−/L at 0.1, 1.6, and 9.2 km downstream sites, respectively) compared with the upstream reference station (0.31 mg F−/L). The 48, 72, 96, 120, and 144-h LC50s (mg F−/L) were 52.6, 25.8, 17.0, 13.4, and 11.5 for Hydropsyche bronta Ross, 102.0, 53.5, 34.7, 27.0, and 21.4 for Hydropsyche occidentalis Banks, and 128.0, 73.2, 42.5, 31.9, and 24.2 for Cheumatopsyche pettiti (Banks). LC50 values for H. bronta were significantly (P<0.05) lower than LC50 values for the other two test species. Abundance and biomass of all hydropsychid species were significantly (P<0.05) lower at the 0.1 km downstream site than at the upstream reference site. H. occidentalis was usually the most abundant species at the reference and 9.2 km downstream stations, with highest abundances at the 9.2 km downstream site. C. pettiti was dominant at 0.1 and 1.6 km downstream sites, showing higher abundances at the 1.6 km downstream site than at the upstream reference site. H. bronta was never collected at 0.1 and 1.6 km downstream sites, but was abundant at the upstream reference site. It is concluded that the fluoride pollution is not a major factor in determining the spatial distribution and abundance of competing hydropsychid species in the Cache la Poudre River. However, the greater sensitivity of H. bronta larvae to fluoride ions could result in decreased abundances of this species at downstream sampling sites.

The relative sensitivity of competing hydropsychid species to fluoride toxicity in the Cache la Poudre River (Colorado)

Resource overlap in the scraper/collector-gatherer guild along temporal, trophic and microspatial niche dimensions was determined at two sites in the Upper Colorado River. The amount of resource overlap within the scraper/collector-gatherer guild in a predictable, benign regulated section of the river was compared with the amount of overlap within the scraper/collector-gatherer guild of a less predictable, frequently disturbed free-flowing section. Thirty years of daily flow records were used to determine predictability and frequency of disturbance events. Trophic, temporal and microspatial overlap between the two guilds was not significantly different. There was no evidence to support the hypothesis that resource overlap should be reduced or more regularly spaced in guilds inhabiting predictable benign environments.

https://www.jstor.org/stable/info/3565903

The influence of environmental predictability/disturbance characteristics on the structure of a guild of mountain stream insects

Leaf litter breakdown in streams receiving treated and untreated metal mine drainage

Larch (Larex decidua Mill.) is an early successional tree species of glacial sediments and valley side-slopes at treeline in the Swiss Alps. In such areas, the needles from this deciduous conifer are a dominant source of particulate organic matter to springs and streams of glacial floodplains. We examined the breakdown of larch needles in 5 stream types of a glacial floodplain in the Swiss Alps in relation to macroinvertebrates, aquatic fungi, and litter nutrient concentrations. The 5 streams ranged from a physically harsh pro-glacial (kryal) stream that lacked significant input of terrestrially derived particulate organic matter to a stable side-slope springbrook that flowed through a mixed larch/pine forest with alder also present in the riparian zone. We hypothesized that needle breakdown (as a surrogate of ecosystem function) would be significantly faster in the springbrook than in the other streams, reflecting differences in macroinvertebrate and fungal assemblages present among streams. Alth...

James V. Ward

Papers

Spatio-temporal patterns of benthic invertebrates along the continuum of a braided Alpine river

The relative sensitivity of competing hydropsychid species to fluoride toxicity in the Cache la Poudre River (Colorado)

The influence of environmental predictability/disturbance characteristics on the structure of a guild of mountain stream insects

Leaf litter breakdown in streams receiving treated and untreated metal mine drainage

Larch needle breakdown in contrasting streams of an alpine glacial floodplain