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Black Urban Growers
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Black Urban Growers (BUGs) is committed to building networks and community support for growers in both urban and rural settings. Through education and advocacy around food and farm issues, we nurture collective Black leadership to support Black agrarianism and reimagine Black futures. Based in New York City, BUGs reach is national through its annual conference.
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Harvard University
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Evaluating the Effects and Effectiveness of Post-fire Seeding Treatments in Western Forests
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Key Findings• In studies that evaluated soil erosion in seeded versus unseeded controls, 78 percent revealed that seeding did not reduce erosion relative to unseeded controls. Even when seeding significantly increased vegetative cover, there was insufficient plant cover to stabilize soils within the first two years after fire. •Sixty percent of the studies reported that seeding deterred native plant recovery in the short-term. •Out of 11 papers that evaluated the ability of seeding to curtail non-native plant species invasions, 54 percent stated that seeding treatments were effective and 45 percent stated they were ineffective.• Forty papers and 67 Burned Area Reports dated between 1970 and 2006 revealed an increased use of native species and annual cereal grains/hybrids during seeding treatments over time, with native species dominating seed mixes. • From 2000 to 2007, total Burned Area Emergency Response (BAER) seeding expenditures have increased substantially, reaching an average of $3.3 million per year—a 192 percent increase compared to the average spent over the previous 30 years.
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Climate Change, Aboveground-Belowground Interactions, and Species’ Range Shifts
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Changes in climate, land use, fire incidence, and ecological connections all may contribute to current species’ range shifts. Species shift range individually, and not all species shift range at the same time and rate. This variation causes community reorganization in both the old and new ranges. In terrestrial ecosystems, range shifts alter aboveground-belowground interactions, influencing species abundance, community composition, ecosystem processes and services, and feedbacks within communities and ecosystems. Thus, range shifts may result in no-analog communities where foundation species and community genetics play unprecedented roles, possibly leading to novel ecosystems. Long-distance dispersal can enhance the disruption of aboveground-belowground interactions of plants, herbivores, pathogens, symbiotic mutualists, and decomposer organisms. These effects are most likely stronger for latitudinal than for altitudinal range shifts. Disrupted aboveground-belowground interactions may have influenced historical postglacial range shifts as well. Assisted migration without considering aboveground-belowground interactions could enhance risks of such range shift–induced invasions.
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Effects of tree mortality caused by a bark beetle outbreak on the ant community in the San Bernardino National Forest
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Ants are used as bioindicators of the effects of disturbance on ecosystems for several reasons. First, ants are generally responsive to alteration of the biomass and diversity of the local plant community (Kalif et al., 2001) and other environmental variables (Underwood & Fisher, 2006). Second, because they occupy fixed nest locations, ants are affected by conditions on a very small scale, so that their presence and abundance are a better indicator of local conditions than are the presence or abundance of more mobile animals (Stephens & Wagner, 2006; Underwood & Fisher, 2006). Ants play important ecosystem roles and are therefore often a relevant choice for monitoring (Ho ̈lldobler & Wilson, 1990). They make up a significant percentage of the animal biomass in many ecosystems, they can be crucial to processes such as soil mixing and nutrient transport (Gentry & Stiritz, 1972), and they are important players in nutrient cycling and energy flow. Ants can also strongly influence the plant community via seed dispersal and granivory (Christian, 2001; Barrow et al., 2007). While the diversity of a given taxon is often not a reliable indicator of the diversity of other groups (Lawton et al., 1998; Bennett et al., 2009; Maleque et al., 2009; Wike et al., 2010), ant diversity is known to reflect the diversity of other invertebrates in ecosystems recovering from a disturbance in some cases (Andersen & Majer, 2004).The use of ants as bioindicators must be undertaken with caution (Underwood & Fisher, 2006). Different ant communities do not always respond to a disturbance in the same way (Arnan et al., 2009). In addition, broad measures of a bioindicator taxon, such as species richness or abundance, are potentially misleading. For instance, while it is popular to measure the species richness of bioindicator groups, the ant species richness of different habitats has been observed to respond differently to similar disturbances (Farji-Brener et al., 2002; Ratchford et al., 2005; Barrow et al., 2007), and ant species richness often does not respond at all unless disturbances are extreme (Andersen & Majer, 2004).Nonetheless, changes in the ant community can provide useful information about the responses of the ecosystem as a whole.
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Disturbance−diversity models: what do they really predict and how are they tested?
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The intermediate disturbance hypothesis (IDH) and the dynamic equilibrium model (DEM) are influential theories in ecology. The IDH predicts large species numbers at intermediate levels of disturbance and the DEM predicts that the effect of disturbance depends on the level of productivity. However, various indices of diversity are considered more commonly than the predicted number of species in tests of the hypotheses. This issue reaches beyond the scientific community as the predictions of the IDH and the DEM are used in the management of national parks and reserves. In order to compare responses with disturbance among measures of biodiversity, we used two different approaches of mathematical modelling and conducted an extensive meta-analysis. Two-thirds of the surveyed studies present different results for different diversity measures. Accordingly, the meta-analysis showed a narrow range of negative quadratic regression components for richness, but not evenness. Also, the two models support the IDH and the DEM, respectively, when biodiversity is measured as species richness, but predict evenness to increase with increasing disturbance, for all levels of productivity. Consequently, studies that use compound indices of diversity should present logical arguments, a priori, to why a specific index of diversity should peak in response to disturbance.
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A-maize-ing Diversity
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Analysis of a new maize resource reveals that a large number of genetic loci with small effects may underlie the wide variation seen in traits such as flowering time.
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Assemblage Time Series Reveal Biodiversity Change but Not Systematic Loss
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The extent to which biodiversity change in local assemblages contributes to global biodiversity
loss is poorly understood. We analyzed 100 time series from biomes across Earth to ask how diversity
within assemblages is changing through time. We quantified patterns of temporal a diversity, measured
as change in local diversity, and temporal b diversity, measured as change in community composition.
Contrary to our expectations, we did not detect systematic loss of a diversity. However, community
composition changed systematically through time, in excess of predictions from null models.
Heterogeneous rates of environmental change, species range shifts associated with climate change,
and biotic homogenization may explain the different patterns of temporal a and b diversity.
Monitoring and understanding change in species composition should be a conservation priority.
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Ecologists Report Huge Storm Losses in China’s Forests
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From delicate orchids and magnolias to rare Chinese yews and Kwangtung pines, the flora of Guangdong
Nanling National Nature Reserve is considered so precious that ecologists call the reserve “a treasure trove of species.” But winter storms have reduced the biological hot spot to a splintered ruin. Snow, sleet, and ice laid waste to 90% of the 58,000- hectare reserve’s forests, says He Kejun, director of Guangdong Forestry
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‘As Earth’s testimonies tell’: wilderness conservation in a changing world
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Too often, wilderness conservation ignores a temporal perspective greater than the past
50 years, yet a long-term perspective (centuries to millennia) reveals the dynamic nature
of many ecosystems. Analysis of fossil pollen, charcoal and stable isotopes, combined
with historical analyses and archaeology can reveal how ongoing interactions between
climatic change, human activities and other disturbances have shaped today’s landscapes
over thousands of years. This interdisciplinary approach can inform wilderness
conservation and also contribute to interpreting current trends and predicting how
ecosystems might respond to future climate change. In this paper, we review literature
that reveals how increasing collaboration among palaeoecologists, archaeologists,
historians, anthropologists and ecologists is improving understanding of ecological
complexity. Drawing on case studies from forested and non-forested ecosystems in
Europe, the Americas, Africa and Australia, we discuss how this integrated approach can
inform wilderness conservation and ecosystem management.
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