Whilst Island Biogeography Theory originally led many to believe that larger, more connected patches of habitat are more important for species conservation, new research suggests that overlooking smaller patches could be dangerous (Image Credit: LuxTonnerre, CC BY 2.0, Image Cropped)
Global synthesis of conservation studies reveals the importance of small habitat patches for biodiversity (2019) Wintle et al., PNAS, https://doi.org/10.1073/pnas.1813051115
Human land use over the past millenia has divided species habitats into smaller and smaller patches – a practice which often leaves conservationists with the tough choice of which remaining patches they should focus their efforts on. Traditional practice has seen the prioritisation of large patches that are well connected to other, with this preference often meaning that smaller more isolated patches are neglected, and often cleared.
This week’s paper authors wanted to check whether this was really the best way of doing things, by looking at the relative conservation value of a variety of habitat patches.
Image Credit: Pete, CC BY-NC 2.0
Increased reproductive success through parasitoid release at a range margin: Implications for range shifts induced by climate change (2020) MacKay, Gross, & Ryder, Journal of Biogeography, https://doi.org/10.1111/jbi.13795
Predicting the response of organisms to climate change is a challenge for ecologists and wildlife managers alike. Fortunately, some responses are common enough that it is still possible to make fairly accurate predictions about them without too much information. One common response is that of the range shift, whereby a population of organisms facing some alteration (eg. climate change) in their current habitat, making it unfavorable, begin to move to another location. This allows them to track favorable environmental conditions and possibly mitigate any negative effects of climate change.
Sounds easy, right? Just pack it all up and move when things get hard? Well, for some organisms it may be that simple (looking at you, birds), but for others (like trees) it is significantly harder to do so. Trees (and other plants) are limited in that they depend on other organisms or things like wind to help disperse their seeds. Making things even more difficult are plant species that depend on specific pollinators, and in order for a successful range shift to happen trees AND their pollinators have to make the move. Today’s authors wanted to study how relationships between trees and their pollinators changed at the leading edge of a range shift, allowing them to understand how and why trees succeed during a range shift.
Birds like this American tree sparrow are declining rapidly, shows a study which looks at huge declines in North American bird populations (Image Credit: Ryan Hodnett, CC BY-SA 4.0, Image Cropped)
Decline of the North American avifauna (2019) Rosenberg et al., Science, DOI: 10.1126/science.aaw1313
When we talk about species loss, we generally focus on extinctions. Too often, when we start to rally around a species, it’s because there are a particularly low number of that species left. In many cases, they’ve often crossed a threshold, from which it’s impossible to pull them back from the brink of extinction.
Often this draws attention away from non-threatened species. Often that’s fine – they’re non-threatened right? But downward population trajectories in these species can still damage ecosystems by lessening the impact of their ecological function, lead to local (if not total) extinctions, and of course, leading them to eventually be threatened.
This week’s authors wanted to look at bird population declines in America, but from the perspective of total abundance, as opposed to a more species-specific view.
Image Credit: Francesco Veronesi, CC BY-SA 2.0, Image Cropped
Macroevolutionary convergence connects morphological form to ecological function in birds (2020) Pigot et al, Nature Ecology & Evolution, https://doi.org/10.1038/s41559-019-1070-4
There are an astounding amount of different forms that the animals on our planet take. Likewise, there are a multitude of diverse functions that animals serve in the environment, such as that of a herbivore, a predator, or scavenger. In some cases it’s a clear link between the form of a given animal and its function in the environment, like that of the beak of a hummingbird that allows it to feed on nectar and their role as a pollinator. But whether or not there is a reliable way to predict the function of an animal based off of its form is has been the subject of considerable controversy.
Deciding on how many morphological traits to use to predict ecological function is a difficult prospect. One could argue that it’s impossible to pick a finite number of traits, as there are infinite possible niches that organisms can fill so there’s no way that a set of traits could fill those infinite possible niches. Mapping animal form to function has major implications for quantifying and and conserving biodiversity, and the authors of today’s paper wanted to to determine just how many traits are needed to do that.
The Amazon rainforest, which houses the largest area of intact forest landscape which lies within indigenous lands (Image Credit: David Evers, CC BY 2.0, Image Cropped)
Importance of Indigenous Peoples’ lands for the conservation of Intact Forest Landscapes (2020) Fa et al., Frontiers in Ecology and the Environment, https://doi.org/10.1002/fee.2148
Pristine forests remain not only a home for a huge range of biodiversity, they are also important resources for carbon storage, meaning their protection will become crucial as temperatures rise globally. Yet the term ‘pristine forest’ can be subjective. With this in mind, Peter Popatov et al., defined an IFL (Intact Forest Landscape) as a seamless mosaic of forest and associated treeless ecosystems that do not display obvious human activity or fragmentation. These areas are capable of housing entire species, including those that have expansive ranges.
The intent of this paper was to try and determine what proportion of that land intersects with land owned by Indigenous Peoples, to see how significant a role Indigenous Peoples could play in both conservation of biodiversity and the mitigation of climate change.
Image Credit: Kevin Pluck, CC BY 2.0, Image Cropped
Brain expansion in early hominins predicts carnivore extinctions in East Africa (2020) Faurby et al, Ecology Letters, https://doi.org/10.1111/ele.13451
We’ve covered humans and their harmful effects many times here on Ecology for the Masses (see my recent breakdown from last month). Despite all of the colorful examples of our current effects on the wildlife of our planet, a significant amount of research has implicated Homo sapiens as the driver of the extinction of some of the megafauna of the prehistoric world, events that happens millions of years ago. Another possibility is that we as organisms (hominins, not Homo sapiens specifically) have been impacting other species for a very, very long time.
Today, East Africa is home to the most diverse group of large carnivores on the planet (though it is still less diverse than what was once seen in North America and Eurasia). Millions of years ago East Africa had an even more diverse assemblage of large carnivores, including bears, dogs, giant otters, and saber-toothed cats. The change in climate since that time may have caused the decline in large carnivore diversity, but another explanation is the rise of early hominins (our ancestors). Using fossil data, the authors of today’s paper wanted to figure out if it was indeed early hominins that drove many large carnivores extinct.
Image Credit: Manfred Antranias Zimmer, Pixabay licence, Image Cropped
Invasion of freshwater ecosystems is promoted by network connectivity to hotspots of human activity (2019) Chapman et al., Global Ecology and Biogeography, https://doi.org/10.1111/geb.13051
The spread of invasive species throughout freshwater ecosystems is a topic we’ve looked at before on Ecology for the Masses. In a previous paper breakdown we talked about how recreational is heavily responsible for the presence of non-native fish at a European scale.
Our paper this week takes a more local approach. Can we predict the presence of non-native birds, invertebrates and fish by looking at the presence of human activity, and where that human activity is present?