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

The management and conservation of the world's oceans require synthesis of spatial data on the distribution and intensity of human activities and the overlap of their impacts on marine ecosystems. We developed an ecosystem-specific, multiscale spatial model to synthesize 17 global data sets of anthropogenic drivers of ecological change for 20 marine ecosystems. Our analysis indicates that no area is unaffected by human influence and that a large fraction (41%) is strongly affected by multiple drivers. However, large areas of relatively little human impact remain, particularly near the poles. The analytical process and resulting maps provide flexible tools for regional and global efforts to allocate conservation resources; to implement ecosystem-based management; and to inform marine spatial planning, education, and basic research.

/pdf/a-global-map-of-human-impact-on-marine-ecosystems-1r5xgg00oe.pdf

A Global Map of Human Impact on Marine Ecosystems

Summary 1 Ecologists use statistical models for both explanation and prediction, and need techniques that are flexible enough to express typical features of their data, such as nonlinearities and interactions 2 This study provides a working guide to boosted regression trees (BRT), an ensemble method for fitting statistical models that differs fundamentally from conventional techniques that aim to fit a single parsimonious model Boosted regression trees combine the strengths of two algorithms: regression trees (models that relate a response to their predictors by recursive binary splits) and boosting (an adaptive method for combining many simple models to give improved predictive performance) The final BRT model can be understood as an additive regression model in which individual terms are simple trees, fitted in a forward, stagewise fashion 3 Boosted regression trees incorporate important advantages of tree-based methods, handling different types of predictor variables and accommodating missing data They have no need for prior data transformation or elimination of outliers, can fit complex nonlinear relationships, and automatically handle interaction effects between predictors Fitting multiple trees in BRT overcomes the biggest drawback of single tree models: their relatively poor predictive performance Although BRT models are complex, they can be summarized in ways that give powerful ecological insight, and their predictive performance is superior to most traditional modelling methods 4 The unique features of BRT raise a number of practical issues in model fitting We demonstrate the practicalities and advantages of using BRT through a distributional analysis of the short-finned eel ( Anguilla australis Richardson), a native freshwater fish of New Zealand We use a data set of over 13 000 sites to illustrate effects of several settings, and then fit and interpret a model using a subset of the data We provide code and a tutorial to enable the wider use of BRT by ecologists

/pdf/a-working-guide-to-boosted-regression-trees-cc9f0o7zb4.pdf

A working guide to boosted regression trees

Sea temperatures in many tropical regions have increased by almost 1 degrees C over the past 100 years, and are currently increasing at similar to 1-2 degrees C per century. Coral bleaching occurs when the thermal tolerance of corals and their photosynthetic symbionts (zooxanthellae) is exceeded. Mass coral bleaching has occurred in association with episodes of elevated sea temperatures over the past 20 years and involves the loss of the zooxanthellae following chronic photoinhibition. Mass bleaching has resulted in significant losses of live coral in many parts of the world. This paper considers the biochemical, physiological and ecological perspectives of coral bleaching. It also uses the outputs of four runs from three models of global climate change which simulate changes in sea temperature and hence how the frequency and intensity of bleaching events will change over the next 100 years. The results suggest that the thermal tolerances of reef-building corals are likely to be exceeded every year within the next few decades. Events as severe as the 1998 event, the worst on record, are likely to become commonplace within 20 years. Most information suggests that the capacity for acclimation by corals has already been exceeded, and that adaptation will be too slow to avert a decline in the quality of the world's reefs. The rapidity of the changes that are predicted indicates a major problem for tropical marine ecosystems and suggests that unrestrained warming cannot occur without the loss and degradation of coral reefs on a global scale.

/pdf/climate-change-coral-bleaching-and-the-future-of-the-world-s-1z4g0rwyaf.pdf

Climate change, coral bleaching and the future of the world's coral reefs

The impact of anthropogenic climate change on terrestrial organisms is often predicted to increase with latitude, in parallel with the rate of warming. Yet the biological impact of rising temperatures also depends on the physiological sensitivity of organisms to temperature change. We integrate empirical fitness curves describing the thermal tolerance of terrestrial insects from around the world with the projected geographic distribution of climate change for the next century to estimate the direct impact of warming on insect fitness across latitude. The results show that warming in the tropics, although relatively small in magnitude, is likely to have the most deleterious consequences because tropical insects are relatively sensitive to temperature change and are currently living very close to their optimal temperature. In contrast, species at higher latitudes have broader thermal tolerance and are living in climates that are currently cooler than their physiological optima, so that warming may even enhance their fitness. Available thermal tolerance data for several vertebrate taxa exhibit similar patterns, suggesting that these results are general for terrestrial ectotherms. Our analyses imply that, in the absence of ameliorating factors such as migration and adaptation, the greatest extinction risks from global warming may be in the tropics, where biological diversity is also greatest.

https://www.pnas.org/content/pnas/105/18/6668.full.pdf

Impacts of climate warming on terrestrial ectotherms across latitude.

Summary
1. We examined published studies relating resting oxygen consumption to body mass and temperature in post-larval teleost fish. The resulting database comprised 138 studies of 69 species (representing 28 families and 12 orders) living over a temperature range of c. 40 °C.

2. Resting metabolic rate (Rb; mmol oxygen gas h–1) was related to body mass (M; wet mass, g) by Rb = aMb, where a is a constant and b the scaling exponent. The model was fitted by least squares linear regression after logarithmic transformation of both variables. The mean value of scaling exponent, b, for the 69 individual species was 0·79 (SE 0·11). The general equation for all teleost fish was 1nRb = 0·80(1nM) – 5·43.

3. The relationship between resting oxygen consumption and environmental temperature for a 50-g fish was curvilinear. A typical tropical fish at 30°C requires approximately six times as much oxygen for resting metabolism as does a polar fish at 0°C. This relationship could be fitted by several statistical models, of which the Arrhenius model is probably the most appropriate. The Arrhenius model for the resting metabolism of 69 species of teleost fish, corrected to a standard body mass of 50 g, was 1nRb = 15·7 – 5·02.T–1, where T is absolute temperature (103 × K).

4. The Arrhenius model fitted to all 69 species exhibited a lower thermal sensitivity of resting metabolism (mean Q10 = 1·83 over the range 0–30 °C) than typical within-species acclimation studies (median Q10 = 2·40, n = 14). This suggests that evolutionary adaptation has reduced the overall thermal sensitivity of resting metabolism across species. Analysis of covariance indicated that the relationships between resting metabolic rate and temperature for various taxa (orders) showed similar slopes but significantly different mean rates.

5. Analysis of the data for perciform fish provided no support for metabolic cold adaptation (the hypothesis that polar fish show a resting metabolic rate higher than predicted from the overall rate/temperature relationship established for temperate and tropical species).

6. Taxonomic variation in mean resting metabolic rate showed no relationship to phylogeny, although the robustness of this conclusion is constrained by our limited knowledge of fish evolutionary history.

https://besjournals.onlinelibrary.wiley.com/doi/pdf/10.1046/j.1365-2656.1999.00337.x

Scaling of metabolic rate with body mass and temperature in teleost fish

It is now clear that hydrogen peroxide (H(2)O(2)) and nitric oxide (NO) function as signalling molecules in plants. A wide range of abiotic and biotic stresses results in H(2)O(2) generation, from a variety of sources. H(2)O(2) is removed from cells via a number of antioxidant mechanisms, both enzymatic and non-enzymatic. Both biotic and abiotic stresses can induce NO synthesis, but the biosynthetic origins of NO in plants have not yet been resolved. Cellular responses to H(2)O(2) and NO are complex, with considerable cross-talk between responses to several stimuli. In this review the potential roles of H(2)O(2) and NO during various stresses and the signalling pathways they activate are discussed. Key signalling components that might provide targets for enhancing crop production are also identified.

Hydrogen peroxide and nitric oxide as signalling molecules in plants

http://www.bio-nica.info/Biblioteca/Meudt2007AFLPApplicationAnalysis.pdf

Almost forgotten or latest practice? AFLP applications, analyses and advances.

At a fundamental level, all of ecology is underpinned by the laws of thermodynamics, the conservation of matter and the general physical principles that dictate how gases and liquids move. Taken altogether, this indicates that there is nothing special about the way organisms function; physiology and ecology are simply physics and chemistry writ complex. In a stimulating review, Lawton (1999) argued that ecology has no laws comparable to physics, but does have what he called widely observable tendencies. These provide a structure for ecology, but they cannot be deduced from first principles. The complication here is scale. At small scales organisms do things that can be analysed, understood and relatively easily predicted. At very large scales (typically continental or global) patterns emerge that can be described statistically; explanations for these global patterns are proving more elusive and this is the challenge of the rapidly developing field of macroecology (Brown 1995). At intermediate scales we are faced with a mixture of contingent case studies and weak generalizations (Lawton 1999). The emerging field of complexity has much to offer here (Maurer 1999), but as yet its impact on mainstream ecology has been small. Organism size has long been recognized as a major factor in ecology and in the 1980s a number of attempts were made to use allometric or scaling techniques to provide a theoretical framework for understanding ecology (Peters 1983; Calder 1984; Schmidt-Nielsen 1984). Despite the stronger claims that allometry provided a theory of size (Peters 1983), the field of scaling has not provided the conceptual framework that is needed, although it has supplied useful analytical tools for studies of energy flow through aquatic food webs (Kerr & Dickie 2001). The problem we face is that a statistical description of phenomena is of limited use if we do not also have a sound understanding of the underlying processes that produce the patterns we observe and describe.

/pdf/why-does-metabolism-scale-with-temperature-10stler6if.pdf

Why does metabolism scale with temperature

Species lists have been compiled for all the major groups of Southern Ocean benthic
marine invertebrates, eliminating synonymies where possible and providing a subjective estimate of completeness and reliability for each group Antarctic marine diversity (pelagic and
benthic) is relatively high at the phylum and class level, with the gaps mostly comprising minor,
meiofaunal or parasitic groups Most benthic diversity data come from the continental shelves,
with relatively few samples from deeper water Even for the continental shelves, however, sampling is highly patchy with some areas hardly investigated at all Over 4100 benthic species
have been reported from the Southern Ocean, with the most speciose groups being polychaetes,
gastropods and amphipods Comparison with tropical and temperate regions suggest that
decapods, bivalves and teleost ﬁshes are poorly represented in the Southern Ocean benthic
marine fauna, whereas pycnogonids, echinoderms and many suspension feeding groups are rich
and diverse Some groups that are currently low in diversity were previously well represented in
the Antarctic shallow water marine fauna, notably decapods and many ﬁshes Other groups have
undergone marked radiations in the Southern Ocean, including pycnogonids, amphipods,
isopods and teleost ﬁshes; in all cases, however, it is only some lineages that have diversiﬁed
This indicates that evolutionary questions concerning the origin, diversiﬁcation or extinction of
the Southern Ocean marine fauna will have no single answer; the evolutionary history of each
group appears to reﬂect a different response to the tectonic, climatic and oceanographic changes
to which they have been subject through history The disposition of southern hemisphere continents makes it difﬁcult to assess whether there is a latitudinal cline in shallow-water marine
diversity to mirror that known from the northern hemisphere Within Antarctica, many species
appear to have circumpolar distributions, and the long established biogeographical division into
continental Antarctic, Antarctic Peninsula and sub-Antarctic regions have not been challenged
by recent sampling For most groups the frequency distribution of species per genus ratios is
typical, though none is well described by the predictions from current evolutionary or null
models Where data are available, size spectra indicate that many Southern Ocean taxa are
small, a few spectacular examples of gigantism notwithstanding, and species abundance plots
are normal Knowledge of the Southern Ocean benthic marine fauna has reached a stage where
we can now ask powerful evolutionary questions, and the development of new molecular techniques provides the mechanism for answering them

Andrew Clarke

Papers

Scaling of metabolic rate with body mass and temperature in teleost fish

Hydrogen peroxide and nitric oxide as signalling molecules in plants

Almost forgotten or latest practice? AFLP applications, analyses and advances.

Why does metabolism scale with temperature

Antarctic marine benthic diversity