Tag Archives: ecology

February 2018 in Review

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Most frightening stories:

  • A general rule across many types of wildlife is that their range after urbanization decreases to between one-half and one-third of what it was before urbanization.
  • The Cuban sonic attacks are real. At least, the people who experienced them have real brain damage, even if we still don’t know what technology did the damage.
  • Cape Town will probably not be the last major city to run out of water.

Most hopeful stories:

Most interesting stories, that were not particularly frightening or hopeful, or perhaps were a mixture of both:

mapping urban vegetation on a fine scale

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This is an interesting paper about mapping urban vegetation on a fine scale based on photos.

Mapping vegetation functional types in urban areas with WorldView-2 imagery: Integrating object-based classification with phenology

Mapping urban vegetation is a prerequisite to accurately understanding landscape patterns and ecological services provided by urban vegetation. However, the uncertainties in fine-scale vegetation biodiversity mapping still exist in capturing vegetation functional types efficiently at fine scale. To facilitate the application of fine-scale vegetation spatial configuration used for urban landscape planning and ecosystem service valuation, we present an approach integrating object-based classification with vegetation phenology for fine-scale vegetation functional type mapping in compact city of Beijing, China. The phenological information derived from two WorldView-2 imagery scenes, acquired on 14 September 2012 and 26 November 2012, was used to aid in the classification of tree functional types and grass. Then we further compared the approach to that of using only one WorldView imagery. We found WorldView-2 imagery can be successfully applied to map functional types of urban vegetation with its high spatial resolution and relatively high spectral resolution. The application of the vegetation phenology into classification greatly improved the overall accuracy of classification from 82.3% to 91.1%. In particular, the accuracies of vegetation types was improved by from 10% to 13.26%. The approach integrating vegetation phenology with high-resolution remote sensed images provides an efficient tool to incorporate multi-temporal data into fine-scale urban classification.

habitat complexity doesn’t affect biodiversity?

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There’s theory, and then there is collecting actual evidence to support a theory, which tends to be messy. In this case, the theory is that more complex habitats should support more diversity. They didn’t at least in this study of insects and spiders in Sydney.

Habitat complexity does not affect arthropod community composition in roadside greenspaces

Urban greenspaces including remnant patches of vegetation, backyard gardens and public parks provide important habitat for wildlife conservation. Maintaining and enhancing the conservation value of these spaces requires both an understanding of the biodiversity they support, and the factors, including habitat traits, influencing species occurrence. Roadside greenspaces, including road verges and median strips are often overlooked in current greenspace biodiversity studies. We quantified arthropod community assemblages in roadside and public park greenspaces, and determined if habitat complexity was an important trait influencing species composition in these areas. Using pitfall traps, we sampled ground dwelling arthropods along five major roads in the greater Sydney Region and in public parks. Whilst roadside greenspaces (road verges and median strips) and public parks supported significantly different arthropod assemblages, habitat complexity had no impact on community assemblage and neither factor affected the assemblage of key arthropods taxa including ants, beetles and spiders. Additionally, in public parks but not road side greenspaces we found an effect of habitat complexity on arthropod abundance; arthropods were more abundant in high complexity park sites. Our results highlight the unique arthropod community assemblage supported by roadside greenspaces, and suggest management practices like increasing habitat complexity may be important in some but not all urban greenspace types.

evidence-based restoration

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If ecosystem restoration hasn’t been based on evidence in the past, what has it been based on?

Evidence-based restoration in the Anthropocene—from acting with purpose to acting for impact

The recognition that we are in the distinct new epoch of the Anthropocene suggests the necessity for ecological restoration to play a substantial role in repairing the Earth’s damaged ecosystems. Moreover, the precious yet limited resources devoted to restoration need to be used wisely. To do so, we call for the ecological restoration community to embrace the concept of evidence-based restoration. Evidence-based restoration involves the use of rigorous, repeatable, and transparent methods (i.e. systematic reviews) to identify and amass relevant knowledge sources, critically evaluate the science, and synthesize the credible science to yield robust policy and/or management advice needed to restore the Earth’s ecosystems. There are now several examples of restoration-relevant systematic reviews that have identified instances where restoration is entirely ineffective. Systematic reviews also serve as a tool to identify the knowledge gaps and the type of science needed (e.g. repeatable, appropriate replication, use of controls) to improve the evidence base. The restoration community, including both scientists and practitioners, needs to make evidence-based restoration a reality so that we can move from best intentions and acting with so-called “purpose” to acting for meaningful impact. Doing so has the potential to serve as a rallying point for reframing the Anthropocene as a so-called “good” epoch.

quantifying ecological functions

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Here is an interesting article on quantifying ecological functions. The main application appears to be wetland mitigation but the theory seems more general and could maybe be adapted to a variety of ecosystem restorations or creations.

Landscape consequences of aggregation rules for functional equivalence in compensatory mitigation programs

Mitigation and offset programs designed to compensate for ecosystem function losses due to development must balance losses from affected ecosystems and gains in restored ecosystems. Aggregation rules applied to ecosystem functions to assess site equivalence are based on implicit assumptions about the substitutability of functions among sites and can profoundly influence the distribution of restored ecosystem functions on the landscape. We investigated the consequences of rules applied to aggregation of ecosystem functions for wetland offsets in the Beaverhill watershed in Alberta, Canada. We considered the fate of 3 ecosystem functions: hydrology, water purification, and biodiversity. We set up an affect-and-offset algorithm to simulate the effect of aggregation rules on ecosystem function for wetland offsets. Cobenefits and trade-offs among functions and the constraints posed by the quantity and quality of restorable sites resulted in a redistribution of functions between affected and offset wetlands. Hydrology and water-purification functions were positively correlated and negatively correlated with biodiversity function. Weighted-average rules did not replace functions in proportion to their weights. Rules prioritizing biodiversity function led to more monofunctional wetlands and landscapes. The minimum rule, for which the wetland score was equal to the worst performing function, promoted multifunctional wetlands and landscapes. The maximum rule, for which the wetland score was equal to the best performing function, promoted monofunctional wetlands and multifunctional landscapes. Because of implicit trade-offs among ecosystem functions, no-net-loss objectives for multiple functions should be constructed within a landscape context. Based on our results, we suggest criteria for the design of aggregation rules for no net loss of ecosystem functions within a landscape context include the concepts of substitutability, cobenefits and trade-offs, landscape constraints, heterogeneity, and the precautionary principle.

more on movement ecology

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I’m still digging into movement ecology, which has always fascinated me. Here is a comprehensive recent literature review on the subject.

Trends and missing parts in the study of movement ecology

Movement is important to all organisms, and accordingly it is addressed in a huge number of papers in the literature. Of nearly 26,000 papers referring to movement, an estimated 34% focused on movement by measuring it or testing hypotheses about it. This enormous amount of information is difficult to review and highlights the need to assess the collective completeness of movement studies and identify gaps. We surveyed 1,000 randomly selected papers from 496 journals and compared the facets of movement studied with a suggested framework for movement ecology, consisting of internal state (motivation, physiology), motion and navigation capacities, and external factors (both the physical environment and living organisms), and links among these components. Most studies simply measured and described the movement of organisms without reference to ecological or internal factors, and the most frequently studied part of the framework was the link between external factors and motion capacity. Few studies looked at the effects on movement of navigation capacity, or internal state, and those were mainly from vertebrates. For invertebrates and plants most studies were at the population level, whereas more vertebrate studies were conducted at the individual level. Consideration of only population-level averages promulgates neglect of between-individual variation in movement, potentially hindering the study of factors controlling movement. Terminology was found to be inconsistent among taxa and subdisciplines. The gaps identified in coverage of movement studies highlight research areas that should be addressed to fully understand the ecology of movement.

An idea that has always fascinated me is the idea that when designing a development or an even an entire urban area, you could actually lead with ecology, then layer hydrology, infrastructure, housing, and the other human elements on top of that. Sadly, I don’t think I know a single engineer or urban planner who would be particularly open minded to this idea.

models for movement and population ecology

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This page has links to some academic/professional models of movement ecology and population ecology, such as predator-prey interactions. It’s something that interests me because with an accurate theory of how animals and plants function and interact in ecosystems over time, it should in principle be possible to design networks of urban, industrial, and agricultural areas that maximize ecological function.

Developing this knowledge would be step one. Of course, there would still be the small matter of our civilization deciding this is something it would like to do.

What are the trends in ecology and evolution for 2018?

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The journal Trends in Ecology and Evolution does an annual “Horizon Scan of Emerging Issues for Global Conservation and Biological Diversity”. I can only see the abstract so here is the one sentence describing the trends:

The issues highlighted span a wide range of fields and include thiamine deficiency in wild animals, the geographic expansion of chronic wasting disease, genetic control of invasive mammal populations and the effect of culturomics on conservation science, policy and action.

I was new to the term culturomics, and thought it might have something to do with synthesizing new compounds in giant vats of yogurt. But no, according to Wikipedia it is not that kind of culture, but relates to search and synthesis algorithms for scientific articles, which does indeed seem to be a recurring theme on this blog lately.

Culturomics is a form of computational lexicology that studies human behavior and cultural trends through the quantitative analysis of digitized texts.[1][2] Researchers data mine large digital archives to investigate cultural phenomena reflected in language and word usage.[3] The term is an American neologism first described in a 2010 Science article called Quantitative Analysis of Culture Using Millions of Digitized Books, co-authored by Harvard researchers Jean-Baptiste Michel and Erez Lieberman Aiden.[4]

At that point, I just needed to figure out what a neologism was, so I looked it up in Webster’s 1913 which some people say is the most artfully written dictionary:

Ne*ol”o*gism (?), n. [Cf. F. néologisme.]

1. The introduction of new words, or the use of old words in a new sense. Mrs. Browning.

2. A new word, phrase, or expression.

3. A new doctrine; specifically, rationalism.

Mrs. Browning? Elizabeth Barrett Browning wrote a long poem called Aurora Leigh which contains the word. And no, I wouldn’t have learned that if I had looked up neologism in the New Oxford American Dictionary.

I learnt my complement of classic French
(Kept pure of Balzac and neologism,)
And German also, since she liked a range
Of liberal education,–tongues, not books.
I learnt a little algebra, a little
Of the mathematics,–brushed with extreme flounce
The circle of the sciences, because
She misliked women who are frivolous.

It goes on like that. Forever.

Oh okay, one more, here is the definition of flounce in Webster’s 1913:

Flounce, v. t. To deck with a flounce or flounces; as, to flounce a petticoat or a frock.

Flounce, n. [Cf. G. flaus, flausch, a tuft of wool or hair; akin to vliess, E.fleece; or perh. corrupted fr. rounce.] An ornamental appendage to the skirt of a woman’s dress, consisting of a strip gathered and sewed on by its upper edge around the skirt, and left hanging.

Flounce (?), v. i. [imp. & p. p.Flounced (flounst); p. pr. & vb. n.Flouncing(?).] [Cf. OSw. flunsa to immerge.] To throw the limbs and body one way and the other; to spring, turn, or twist with sudden effort or violence; to struggle, as a horse in mire; to flounder; to throw one’s self with a jerk or spasm, often as in displeasure.

To flutter and flounce will do nothing but batter and bruise us.

Barrow.

With his broad fins and forky tail he laves
The rising sirge, and flounces in the waves.

Addison.

“Sirge” I think is an old-timey spelling of “surge”. And if you look up “surge” in this dictionary, its usage is quite interesting and you want to go on. But that’s it for me.

 

game of (bee) thrones

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Queen bees demand, and receive, absolute loyalty from their hives. When they are nearing the end of their reigns, they try to arrange to keep their family in power and have one of their daughters assume the throne. But that doesn’t always work out and the struggle over succession can be pretty brutal. This might give George R.R. Martin some ideas.

As far as I can tell, my queen died sometime in the spring. Queens typically live for about four or five years, so this caught me by surprise. A new queen, however, is a regular event in the life of a hive. Beekeepers frequently replace their queens every year or two to introduce genetic variety and ensure that the hive has a strong monarch who can lay enough eggs to keep the population up. Bees can also raise their own queen, and when I did an inspection early that spring, I was pleased to see that mine had taken the initiative. Before she died, my old queen must have laid a few fertilized eggs that worker bees raised as replacements. They would have selected six or seven fertilized (female) eggs and fed them only royal jelly. When the first queen hatched, she would have immediately killed any unhatched competition and ideally flown a few mating flights, storing enough semen in her abdomen to spend the rest of her life laying eggs.

While a newborn queen may seem ruthless, the success of a beehive hinges on allegiance to its queen. Though she can mate with an average of 12 different drones, there is only one queen, which makes for a hive of closely related bees. As a new queen begins to produce her own pheromones, the hive slowly aligns with her as the old bees die and new workers hatch. In a sense, the hive is genetically wired to be loyal to the monarchy. If the hive was to raise multiple queens, or if the workers were to start laying eggs, the interests of the population would slowly fracture…

Bees have about 165 pheromone receptors on their antennae and though it’s not entirely clear how workers “decide” what to do and when (the question of agency is still very much up for debate), it is certain that the queen’s pheromones prompt them to go about their business. When the reigning monarch dies or stops laying eggs in her old age, the change in her pheromones prompts the hive to raise a replacement, as my hive had done. Similarly, if a new queen arrives and releases her pheromones before those of the old queen have dispersed, the hive will consider the new queen an invader, and kill her. Above all, they are loyal to their queen. I did not fully grasp this fact. Because I waited only six hours between queens, the worker bees probably stung my new queen to death within an hour.

a prosperous way down

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This paragraph caught my eye in the blog A Prosperous Way Down:

The environment is not an element (subsystem) of the economy/finance role-playing game. The economy is actually a subsystem of society, which is embedded in the geobiosphere, its super-system. From a systems perspective, any rearrangement of the geobiosphere as a result of new driving forces, including anthropogenic emissions, affects the behavior, the stability and the sustainability of the global economy as a subsystem. Economically based choices do impact the environment, but the geobiosphere then readjusts its operation (somewhat unpredictably) and impacts the behavior of the global economy itself. Any hope to make significant changes to the global environment (the super-system) while at the same time keeping the operation of our economy fixed or expanding is inconsistent with systems thinking. But this seems to be exactly what people are trying to do, by trying to freeze the current status of the environment as a provider of raw material and ecosystem services that can guarantee economic growth.

If you think about it enough, it becomes fairly obvious that humans are not that different than other animals trying to gain an advantage by exploiting finite energy and other resources in our environment. We are such ingenious exploiters that we have been able to pretend the environment isn’t there, but it seems clear that the environment may finally be catching up with us. Reorienting the principles of economics in an ecological framework seems like an obvious and clear thing to do.