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Opportunities to conduct large-scale field experiments are rare, but provide a unique opportunity to reveal the complex processes that operate within natural ecosystems. Here, we review the design of existing, large-scale forest fragmentation experiments. Based on this review, we develop a design for the Stability of Altered Forest Ecosystems (SAFE) Project, a new forest fragmentation experiment to be located in the lowland tropical forests of Borneo (Sabah, Malaysia). The SAFE Project represents an advance on existing experiments in that it: (i) allows discrimination of the effects of landscape-level forest cover from patch-level processes; (ii) is designed to facilitate the unification of a wide range of data types on ecological patterns and processes that operate over a wide range of spatial scales; (iii) has greater replication than existing experiments; (iv) incorporates an experimental manipulation of riparian corridors; and (v) embeds the experimentally fragmented landscape within a wider gradient of land-use intensity than do existing projects. The SAFE Project represents an opportunity for ecologists across disciplines to participate in a large initiative designed to generate a broad understanding of the ecological impacts of tropical forest modification.

Question: How does experimental habitat fragmentation of a temperate Australian eucalypt forest affect local population patterns of common plant species 22 yr after landscape transformation to a pine plantation? Location: Wog Wog Habitat Fragmentation Experiment, southeast Australia. Methods: We use occupancy—scale relationships to examine the patterns of community organization of common understorey plant species in fragmented forests (small: 0.25 ha; large: 3.062 ha) relative to an intact native forest. Results: Occupancy—scale patterns for intact forest and large-sized remnants were isotropic; slope (z) values ranged across all values, from aggregated to scattered. In the smallest remnants, however, mean and median z values, as well as their interquartile range, were significantly lower than expected. The convergence in occupancy—scale relationships in small remnants hints that many of the commonest plant species have become even more common (i.e. aggregated). Conclusions: The ecological assembly processes that influence common species in small-sized remnants differ from those in larger remnants and intact forest. Fragmentation effects on assembly processes are greater at smaller patch sizes because these habitats are likely altered by changed environmental filters more so than large patches. Such shifts may have implications for habitat structure, ecosystem function and food web interactions in small remnant forests.

Habitat conversion and fragmentation threaten biodiversity and disrupt species interactions. While parasites are recognized as ecologically important, the impacts of fragmentation on parasitism are poorly understood relative to other species interactions. This lack of understanding is in part due to confounding landscape factors that accompany fragmentation. Fragmentation experiments provide the opportunity to fill this knowledge gap by mechanistically testing how fragmentation affects parasitism while controlling landscape factors. In a large-scale, long-term experiment, we asked how fragmentation affects a host–parasite interaction between a skink and a parasitic nematode, which is trophically transmitted via a terrestrial amphipod intermediate host. We expected that previously observed amphipod declines resulting from fragmentation would result in decreased transmission of nematodes to skinks. In agreement, we found that nematodes were absent among skinks in the cleared matrix and that infections in fragments were about one quarter of those in continuous forest. Amphipods found in gut contents of skinks and collected from pitfall traps mirrored this pattern. A structural equation model supported the expectation that fragmentation disrupted this interaction by altering the abundance of amphipods and suggested that other variables are likely also important in mediating this effect. These findings advance understanding of how landscape change affects parasitism.

ContextEarth's forests are fragmented. Species' long-term persistence depends on their conservation in fragmented landscapes with remnants embedded in a matrix of human land use. This matrix influences species' persistence in fragments by determining their degree of isolation and the extent to which edge effects alter habitat. Matrix habitat is often dynamic, so its impact on persistence of remnant species changes over time.ObjectivesPrevious research showed that the abundance response of predatory beetle species to matrix habitat predicted their response in fragments with a log-response ratio of about 0.5. When abundance declined in the matrix, there was a smaller but predictable decline in fragments. However, the predictive utility of a fragment:matrix log-response ratio needs testing with functionally different species, more detailed data, and a focus on mechanism.MethodsIn the Wog Wog habitat fragmentation experiment, we follow a detritivorous amphipod 27 years after forest fragmentation.ResultsThe amphipod's response in habitat fragments was predicted by its response in the matrix with a log-response ratio of about 0.5, similar to predatory beetles. The amphipod's response was explained by its abiotic niche. The amphipod's short-term response did not predict its long-term response.ConclusionsThe log-response ratio might generalize across the invertebrate food web. For two groups within the Wog Wog experiment, a species' dynamic response in matrix habitat predicted its persistence in fragments. Future work should explore the generality of this finding. With knowledge of projected land use of matrix habitat, a species' matrix response could be used for management planning.

ContextIncreasing rates of habitat fragmentation globally underscore the importance of understanding the full spectrum of fragmentation’s ecological consequences. Fragmentation alters the thermal environment of fragments, which may alter the body size of ectothermic organisms and in turn impact survival and reproduction.ObjectivesTo determine whether experimental habitat fragmentation alters body size in the heliothermic, ground-dwelling common garden skink (Lampropholis guichenoti).MethodsWe use body size data spanning 29 years to experimentally test the prediction that lizards will experience morphological changes in forest fragments but not in non-fragmented controls.ResultsLizards were smaller in forest fragments relative to those in the non-fragmented controls after the fragmentation treatment was applied. For lizards within forest fragments, the greater the exposure to deforested areas, the greater the decline in body size. This pattern was strongest in the first 5 years following fragmentation and weakened or reversed over time as the pine plantation matrix surrounding the fragments matured. Using sampling site-scale temperature data for the most recent 5 years of the experiment, we show that temperature predicts lizard body size. Our findings are consistent with predictions made under the temperature-size rule that ectotherms will be smaller in fragmented landscapes because of temperature increases at newly created edges.ConclusionsOur results raise new concerns about the effects of fragmentation on organisms in remnant patches and offer new research priorities, as more evidence is needed to determine the generality of body size declines in fragmented landscapes. Our results also highlight that body size declines, often attributed to climate change, may be amplified by habitat fragmentation, which has been global in its impact.

This chapter contains sections titled: Habitats Habitats and resources in the landscape Habitat gradients for beetles Remnant habitat values: brownfield sites Islands and island habitats